https://microbewiki.kenyon.edu/api.php?action=feedcontributions&user=Jsamore&feedformat=atommicrobewiki - User contributions [en]2024-03-28T14:46:44ZUser contributionsMediaWiki 1.39.6https://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=18132Lactobacillus acidophilus2007-06-05T16:19:14Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Ecology see Ecology]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Probiotic Effects Beyond the GI Tract===<br />
<br />
''L. acidophilus'' has long been considered a probiotic conferring digestive benefits to its host. Now research is beginning to examine ''L. acidophilu's'' potential probiotic effect in combating vulvovaginal candidiasis (VVC). VVC is associated with a low number of ''Lactobacilli'' in the vagina or with peroxide-non-producing vaginal ''Lactobacilli''. A review of the literature shows no clear indication of whether or not ''L. acidophilus'' is effective in all VVC cases. The studies are preliminary and had methodological problems such as small sample size, lacked a control group and included women without confirmed VVC. Further studies are necessary with appropriate experimental design. Additionally, studies regarding oral or intravaginal dosage are necessary to determine a more efficient administration of the probiotics. [http://jac.oxfordjournals.org/cgi/content/full/58/2/266 (5)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential display; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
5. [http://jac.oxfordjournals.org/cgi/content/full/58/2/266 Falagas, M.E., Betsi, G.I. and Athanasiou, S. "Probiotics for prevention of recurrent vulvovaginal candidiasis: a review". ''Journal of Antimicrobial Chemotherapy''. 2006. Volume 58. Pages 266-272.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=18130Lactobacillus acidophilus2007-06-05T16:18:54Z<p>Jsamore: /* Current Research */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Ecology see Ecology]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Probiotic Effects Beyond the GI Tract===<br />
<br />
''L. acidophilus'' has long been considered a probiotic conferring digestive benefits to its host. Now research is beginning to examine ''L. acidophilu's'' potential probiotic effect in combating vulvovaginal candidiasis (VVC). VVC is associated with a low number of ''Lactobacilli'' in the vagina or with peroxide-non-producing vaginal ''Lactobacilli''. A review of the literature shows no clear indication of whether or not ''L. acidophilus'' is effective in all VVC cases. The studies are preliminary and had methodological problems such as small sample size, lacked a control group and included women without confirmed VVC. Further studies are necessary with appropriate experimental design. Additionally, studies regarding oral or intravaginal dosage are necessary to determine a more efficient administration of the probiotics. [http://jds.fass.org/cgi/reprint/84/2/319 (5)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential display; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
5. [http://jac.oxfordjournals.org/cgi/content/full/58/2/266 Falagas, M.E., Betsi, G.I. and Athanasiou, S. "Probiotics for prevention of recurrent vulvovaginal candidiasis: a review". ''Journal of Antimicrobial Chemotherapy''. 2006. Volume 58. Pages 266-272.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=18127Lactobacillus acidophilus2007-06-05T16:18:24Z<p>Jsamore: /* References */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Ecology see Ecology]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Probiotic Effects Beyond the GI Tract===<br />
<br />
''L. acidophilus'' has long been considered a probiotic conferring digestive benefits to its host. Now research is beginning to examine ''L. acidophilu's'' potential probiotic effect in combating vulvovaginal candidiasis (VVC). VVC is associated with a low number of ''Lactobacilli'' in the vagina or with peroxide-non-producing vaginal ''Lactobacilli''. A review of the literature shows no clear indication of whether or not ''L. acidophilus'' is effective in all VVC cases. The studies are preliminary and had methodological problems such as small sample size, lacked a control group and included women without confirmed VVC. Further studies are necessary with appropriate experimental design. Additionally, studies regarding oral or intravaginal dosage are necessary to determine a more efficient administration of the probiotics.<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential display; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
5. [http://jac.oxfordjournals.org/cgi/content/full/58/2/266 Falagas, M.E., Betsi, G.I. and Athanasiou, S. "Probiotics for prevention of recurrent vulvovaginal candidiasis: a review". ''Journal of Antimicrobial Chemotherapy''. 2006. Volume 58. Pages 266-272.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=18119Lactobacillus acidophilus2007-06-05T16:15:22Z<p>Jsamore: /* References */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Ecology see Ecology]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Probiotic Effects Beyond the GI Tract===<br />
<br />
''L. acidophilus'' has long been considered a probiotic conferring digestive benefits to its host. Now research is beginning to examine ''L. acidophilu's'' potential probiotic effect in combating vulvovaginal candidiasis (VVC). VVC is associated with a low number of ''Lactobacilli'' in the vagina or with peroxide-non-producing vaginal ''Lactobacilli''. A review of the literature shows no clear indication of whether or not ''L. acidophilus'' is effective in all VVC cases. The studies are preliminary and had methodological problems such as small sample size, lacked a control group and included women without confirmed VVC. Further studies are necessary with appropriate experimental design. Additionally, studies regarding oral or intravaginal dosage are necessary to determine a more efficient administration of the probiotics.<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential display; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
5. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Probiotics for prevention of recurrent vulvovaginal candidiasis: a review". ''Journal of Antimicrobial Chemotherapy''. 2006. Volume 58. Pages 266-272.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=18114Lactobacillus acidophilus2007-06-05T16:13:22Z<p>Jsamore: /* Probiotic Effects Beyond the GI Tract */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Ecology see Ecology]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Probiotic Effects Beyond the GI Tract===<br />
<br />
''L. acidophilus'' has long been considered a probiotic conferring digestive benefits to its host. Now research is beginning to examine ''L. acidophilu's'' potential probiotic effect in combating vulvovaginal candidiasis (VVC). VVC is associated with a low number of ''Lactobacilli'' in the vagina or with peroxide-non-producing vaginal ''Lactobacilli''. A review of the literature shows no clear indication of whether or not ''L. acidophilus'' is effective in all VVC cases. The studies are preliminary and had methodological problems such as small sample size, lacked a control group and included women without confirmed VVC. Further studies are necessary with appropriate experimental design. Additionally, studies regarding oral or intravaginal dosage are necessary to determine a more efficient administration of the probiotics.<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17941Lactobacillus acidophilus2007-06-05T15:07:15Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Ecology see Ecology]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Probiotic Effects Beyond the GI Tract===<br />
<br />
''L. acidophilus'' has long been considered a probiotic conferring digestive benefits to its host. Now research is turning to examine ''L. acidophilu's'' potential probiotic effect in combating vulvovaginal candidiasis (VVC). VVC is associated with a low number of ''Lactobacilli'' in the vagina or with peroxide-non-producing vaginal ''Lactobacilli''. A review of the literature shows no clear indication whether or not ''L. acidophilus'' is effective in all VVC cases. The studies are preliminary, but are promising. <br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17878Lactobacillus acidophilus2007-06-05T14:22:28Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Ecology see Ecology]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17877Lactobacillus acidophilus2007-06-05T14:21:38Z<p>Jsamore: /* Application */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17874Lactobacillus acidophilus2007-06-05T14:20:24Z<p>Jsamore: /* Species */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''Lactobacillus acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17873Lactobacillus acidophilus2007-06-05T14:20:10Z<p>Jsamore: /* Higher order taxa */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17810Lactobacillus acidophilus2007-06-05T12:47:48Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. <br />
<br />
''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17802Lactobacillus acidophilus2007-06-05T12:41:12Z<p>Jsamore: /* Innate Antimicrobial Activity */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium'', and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17800Lactobacillus acidophilus2007-06-05T12:40:22Z<p>Jsamore: /* Genome structure */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Proteins that allow for ''L. acidophilus's'' unique metabolic functions and ability to survive acid conditions were also identified. These include gene clusters that allow for transport of a diverse group of carbohydrates, such as fructooligosaccharides and raffinose, and were often associated with transcriptional regulators. Coupled regulatory systems between acid tolerance and bacteriocin production are predicted in 9 locations. Overall these genes enable ''L. acidophilus'' to survive in the harsh GI conditions and promote interaction with the intestinal mucosa and microbiota. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17791Lactobacillus acidophilus2007-06-05T12:34:36Z<p>Jsamore: /* Current Research */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17790Lactobacillus acidophilus2007-06-05T12:34:12Z<p>Jsamore: /* Innate Antimicrobial Activity */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''.<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17789Lactobacillus acidophilus2007-06-05T12:33:58Z<p>Jsamore: /* Application */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''.<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17787Lactobacillus acidophilus2007-06-05T12:33:35Z<p>Jsamore: /* Cell structure and metabolism */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (4)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''.<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17786Lactobacillus acidophilus2007-06-05T12:33:20Z<p>Jsamore: /* Genome structure */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (3)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''.<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17784Lactobacillus acidophilus2007-06-05T12:32:58Z<p>Jsamore: /* References */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''.<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
4. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17781Lactobacillus acidophilus2007-06-05T12:32:14Z<p>Jsamore: /* Genome structure */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. No complete prophages were found, but 9 phage-related integrases are predicted to remain as remnants. Additionally, 3 unique regions classified as potential autonomous units (PAUs) were identified. PAUs have unique characteristics that suggest that they are phage or plasmid remnants, but have not be further classified at this point. A unique signature sequence was noted. It is composed of 32 repeats of 29 base pairs (bps). [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''.<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17773Lactobacillus acidophilus2007-06-05T12:22:09Z<p>Jsamore: /* Current Research */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''.<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=17771Lactobacillus acidophilus2007-06-05T12:20:57Z<p>Jsamore: /* Current Research */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
Adherence to the epithelium of the GI tract is thought to play an important role in the probiotic effect of ''L. acidophilus''. Stuies show that the exact mechanism of adherence varies from strain to strain. Possible mechanisms include protein and carbohydrate mediated adherence. Although both types of mechanisms have been demonstrated ''in vitro'' neither has successfully been demonstrated ''in vivo''. Because the GI tract is a constantly changing environment it is difficult to mimic the environment ''in vitro''. Further studies with biopsies of intestinal tissues are necessary to confirm adherence and retention of ''L. acidophilus'' in the GI tract. However, studies that include such biopsies are rare. ''In vitro'', NCFM specifically shows a protein mediated response. The NCFM that demonstrated adherence did not appear to have a polysaccharide layer, which may be significant to its ability to adhere. Further study is needed to confirm mechanisms ''in vivo''.<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
===More About the Probiotic Effects of ''L. acidophilus''===<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16830Lactobacillus acidophilus2007-06-05T07:44:00Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM produces a bacteriocin, called lactacin B that demonstrates antimicrobial activity against other ''Lactobacilli'' and ''Enterococcus faecalis''. The molecular mass of lactacin B is 6500 Daltons and is sensitive to proteinase K and pronase. It is stable between temperatures ranging from 121˚C to -20˚C. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
===More About the Probiotic Effects of ''L. acidophilus''===<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16809Lactobacillus acidophilus2007-06-05T07:39:16Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect). In the laboratory strain NCFM demonstrated antagonistic activity against common foodborne disease agents such as ''Staphylcoccus aureus'', ''Salmonella typhimurium", and enteropathogenis ''Escherichia coli''. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
===More About the Probiotic Effects of ''L. acidophilus''===<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16788Lactobacillus acidophilus2007-06-05T07:35:13Z<p>Jsamore: /* Innate Antimicrobial Activity */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
When ''L. acidophilus'' is co-cultivated with other organisms, ''L. acidophilus'' has repeatedly been shown to inhibit the growth of competing microbes. It is thought that ''L. acidophilus'' produces a variety of antimicrobial compounds including organic acids, hydrogen peroxide, diacetyl and bacteriocins. The activity of these compounds is evident in the laboratory, but the ''in vivo'' role of these compounds is less clear. This is an area of active research. For instance, human fecal samples show a correlation between a reduction in pH and an increase in short chain fatty acids with higher fecal counts of ''Lactobacilli'' and ''bifidobacteria'' (which is another species that exhibits a probiotic effect).<br />
<br />
===More About the Probiotic Effects of ''L. acidophilus''===<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16743Lactobacillus acidophilus2007-06-05T07:26:25Z<p>Jsamore: /* Strains */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory:</b> NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human:</b>HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig:</b> PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken:</b> C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
===More About the Probiotic Effects of ''L. acidophilus''===<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16736Lactobacillus acidophilus2007-06-05T07:25:24Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
===Innate Antimicrobial Activity===<br />
<br />
===More About the Probiotic Effects of ''L. acidophilus''===<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16729Lactobacillus acidophilus2007-06-05T07:24:07Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
===Protein Mediated Adherence===<br />
<br />
===Bacteriocins===<br />
<br />
===More About the Probiotic Effects of ''L. acidophilus''===<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16717Lactobacillus acidophilus2007-06-05T07:21:30Z<p>Jsamore: /* Application */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability to adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population in favor of the host's health. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16712Lactobacillus acidophilus2007-06-05T07:20:44Z<p>Jsamore: /* Cell structure and metabolism */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and as a result are unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16709Lactobacillus acidophilus2007-06-05T07:20:19Z<p>Jsamore: /* Description and Significance */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles in industry. They contribute to the production of some cheeses, yogurt, and other products. The lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product in these products. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. Since then ''L. acidophilus'' has been further characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16499Lactobacillus acidophilus2007-06-05T06:54:14Z<p>Jsamore: /* Genome structure */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16493Lactobacillus acidophilus2007-06-05T06:53:56Z<p>Jsamore: /* Application */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16487Lactobacillus acidophilus2007-06-05T06:53:21Z<p>Jsamore: /* Application */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
''L. acidophilus'' is best known as a probiotic. The exact mechanism of the probiotic effect is still under investigation. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research])<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16480Lactobacillus acidophilus2007-06-05T06:52:34Z<p>Jsamore: /* Cell structure and metabolism */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that the only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16476Lactobacillus acidophilus2007-06-05T06:52:10Z<p>Jsamore: /* Description and Significance */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), is homofermentative and has optimal growth at temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16449Lactobacillus acidophilus2007-06-05T06:49:23Z<p>Jsamore: /* Description and Significance */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, was isolated from a human in 1970 and characterized at North Carolina State University. NCFM has been commercially available in the United States as a probiotic strain since the mid-1970s. NCFM is also used for formula, yogurt and fluid milk production. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16431Lactobacillus acidophilus2007-06-05T06:46:35Z<p>Jsamore: /* Genome structure */</p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,864 open reading frames (ORFs) and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16382Lactobacillus acidophilus2007-06-05T06:42:20Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16379Lactobacillus acidophilus2007-06-05T06:42:05Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16373Lactobacillus acidophilus2007-06-05T06:41:37Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". For further information about ''L. acidophilus''as a probiotic refer to the applications section below ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Application see Application]). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=16356Lactobacillus acidophilus2007-06-05T06:39:39Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' is the largest genus of the lactic acid bacteria group and includes over 50 species. ''Lactobacilli'' commonly inhabit the gastrointestinal (GI) tract, oral, and vaginal regions of humans and animals. ''Lactobacilli'' have many important roles: in industry they contribute to the production of some cheeses, yogurt, and other products. In these products, the lactic acid produced by ''Lactobacilli'' inhibits the growth of other organisms and lowers the pH of the product. The starter cultures for such products are carefully cultivated and maintained because their metabolic end products contribute to the flavor of the final food product. Additionally, some of ''Lactobacilli's'' metabolic reactions are intentionally manipulated to breakdown milk proteins during cheese production. <br />
<br />
Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C. Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. The World Health Organization defines a probiotic as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host". For further information about ''L. acidophilus''as a probiotic refer to the applications section below. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=15911Lactobacillus acidophilus2007-06-05T05:24:29Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' inhabit the gastrointestinal (GI) tract of humans and animals. ''Lactobacilli'' are considered to have a probiotic effect that contributes to overall health and well being.<br />
<br />
Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C.[http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Application==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=15580Lactobacillus acidophilus2007-06-05T04:01:45Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' inhabit the gastrointestinal (GI) tract of humans and animals. ''Lactobacilli'' are considered to have a probiotic effect that contributes to overall health and well being.<br />
<br />
Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short Gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C.[http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Pathology==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=11998Lactobacillus acidophilus2007-05-31T03:55:14Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' inhabit the gastrointestinal (GI) tract of humans and animals. ''Lactobacilli'' are considered to have a probiotic effect that contributes to overall health and well being.<br />
<br />
Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C.[http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7). [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Pathology==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]). [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545.]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331.]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=11997Lactobacillus acidophilus2007-05-31T03:53:51Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' inhabit the gastrointestinal (GI) tract of humans and animals. ''Lactobacilli'' are considered to have a probiotic effect that contributes to overall health and well being.<br />
<br />
Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C.[http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 (1)]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally.[http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906 (2)]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only.[http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7).[http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x (3)]<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Pathology==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]).[http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract.[http://jds.fass.org/cgi/reprint/84/2/319 (4)]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545. ]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331. ]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=11995Lactobacillus acidophilus2007-05-31T03:51:55Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' inhabit the gastrointestinal (GI) tract of humans and animals. ''Lactobacilli'' are considered to have a probiotic effect that contributes to overall health and well being.<br />
<br />
Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C.[http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 1]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally.[http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only.[http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7).[http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Pathology==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]).[http://jds.fass.org/cgi/reprint/84/2/319]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract.[http://jds.fass.org/cgi/reprint/84/2/319]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545. ]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331. ]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=11993Lactobacillus acidophilus2007-05-31T03:51:11Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' inhabit the gastrointestinal (GI) tract of humans and animals. ''Lactobacilli'' are considered to have a probiotic effect that contributes to overall health and well being.<br />
<br />
Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C.[http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162]<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally.[http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
''L. acidophilus'' NCFM contains no plasmids. [http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only.[http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x]<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7).[http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Pathology==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. [http://jds.fass.org/cgi/reprint/84/2/319]<br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]).[http://jds.fass.org/cgi/reprint/84/2/319]<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract.[http://jds.fass.org/cgi/reprint/84/2/319]<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545. ]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331. ]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=11991Lactobacillus acidophilus2007-05-31T03:47:15Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' inhabit the gastrointestinal (GI) tract of humans and animals. ''Lactobacilli'' are considered to have a probiotic effect that contributes to overall health and well being.<br />
<br />
Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C.[http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162]<br />
<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally.<br />
<br />
''L. acidophilus'' NCFM contains no plasmids.<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only.<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7).<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
<br />
==Pathology==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. <br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]).<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract.<br />
<br />
==Application to Biotechnology==<br />
<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545. ]<br />
<br />
2. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331. ]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamorehttps://microbewiki.kenyon.edu/index.php?title=Lactobacillus_acidophilus&diff=11990Lactobacillus acidophilus2007-05-31T03:45:49Z<p>Jsamore: </p>
<hr />
<div>{{Biorealm Genus}}<br />
<br />
==Classification==<br />
<br />
===Higher order taxa===<br />
<br />
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus<br />
<br />
===Species===<br />
<br />
''L. acidophilus''<br />
{|<br />
| height="10" bgcolor="#FFDF95" |<br />
'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1579 Taxonomy][http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=82 Genome]'''<br />
|}<br />
<br />
==Strains==<br />
<br />
<b>Laboratory</b>: NCFM, 4962, CNRZ216, CNRZ218<br />
<br />
<b>Human</b>: HA1, HA2, HA3, HM2, HM6<br />
<br />
<b>Pig</b>: PA3, PA12, PA19, P18, P47<br />
<br />
<b>Chicken</b>: C1, C2, C3, C7, C11<br />
<br />
==Description and Significance==<br />
<br />
In general, ''Lactobacilli'' inhabit the gastrointestinal (GI) tract of humans and animals. ''Lactobacilli'' are considered to have a probiotic effect that contributes to overall health and well being.<br />
<br />
Of the ''Lactobacillus'' species, ''L. acidophilus'' is the most well known and is commercially distributed as a probiotic. Early studies of ''L. acidophilus'' were performed on strains isolated from fecal material of humans, pigs and chickens. It has been characterized as a short gram-positive rod (2-10μm), homofermentative and optimal growth temperatures of 37˚C-42˚C.<br />
<br />
Further isolation and investigation into the physiological, biochemical, genetic, and fermentative properties have been widely explored in both humans and animals. The ''L. acidophilus'' strain, NCFM, has been commercially available in the United States as a probiotic strain since the mid-1970s. [http://www.pnas.org/cgi/content/full/102/11/3906]<br />
<br />
==Genome structure==<br />
The complete circular genome of the NCFM strain of ''L. acidophilus'' contains 1,993,564 nucleotides. The DNA GC content was determined to be 34.71%. There are 1,7864 ORFs and 72.5% have been classified functionally.<br />
<br />
''L. acidophilus'' NCFM contains no plasmids.<br />
<br />
==Cell structure and metabolism==<br />
<br />
<br />
''L. acidophilus'' grows in low pH (<3.5), anaerobic conditions and undergoes fermentation only.<br />
<br />
In 1999, an H<sup>+</sup> induced ATPase was identified in ''L. acidophilus''. Based on primary structure and the genetic organization, it was further classified as a F<sub>1</sub>F<sub>0</sub>-type ATPase. Its similarity to the streptococcal ATPase and the H<sup>+</sup> inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH (~7).<br />
<br />
''L. acidophilus'' lack cytochromes, porphyrins, and respiratory enzymes and are therefore unable to undergo any oxidative phosphorylation or respiration. Because they utilize sugars as their substrates for fermentation, they inhabit environments with high sugar abundance, such as the GI tract in humans and animals. More specifially, ''L. acidophilus'' is homofermentative which means that they only byproduct it forms from fermentation is lactic acid. For every one glucose molecule that undergoes fermentation in ''L. acidophilus'', the energy yield is two ATPs. As a result, homofermentative microbes must catabolize large amounts of substrate to generate enough energy for growth. In addition to glucose, ''L. acidophilus'' utilizes aesculin, cellobiose, galactose, lactose, maltose, salicin, sucrose, and trehalose for fermentation.<br />
<br />
==Ecology==<br />
<br />
<br />
==Pathology==<br />
<br />
The exact mechanism of the probiotic effect is still under investigation.<br />
<br />
Adherence and colonization is one of many suggested mechanisms responsible for the probiotic effect of ''L. acidophilus''. Adherence and colonization of the intestinal epithelium can act in two ways: (1) competition for space in on the epithelium and (2) interaction with enterocytes. There is some evidence that ''L. acidophilus'' NCFM has the ability adhere through a protein mediated mechanism. ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]) After ''L. acidophilus'' has colonized the GI tract, as a probiotic bacteria it has the potential to influence the existing microbial population. <br />
<br />
Antimicrobial activity is a considered an important mechanism by which probiotic bacteria act to inhibit a range of microbes that have potentially detrimental effects. It is suggested that ''L. acidophilus'' produces bacteriocins (proteins that are active against other bacteria). This specific mechanism is currently being researched ([http://microbewiki.kenyon.edu/index.php/Lactobacillus_acidophilus#Current_Research see Current Research]).<br />
<br />
''L. acidophilus'' has been suggested as a supplement for lactose intolerant individuals. When taken orally and in sufficient dosages, there is evidence for a decrease in symptoms of lactose maldigestion. Presumably, the ''L. acidophilus'' colonizes the GI tract and contributes to the metabolism of lactose during digestion and transit through the GI tract.<br />
<br />
==Application to Biotechnology==<br />
<br />
<br />
==Current Research==<br />
<br />
<br />
==References==<br />
1. [http://www.pnas.org/cgi/content/full/102/11/3906 Altermann, E., Russell, W.M., Azcarate-Peril, M.A., et al. "Complete genome sequence of the probiotic lactic acid bacterium ''Lactobacillus acidophilus'' NCFM". ''Proceedings of the National Academy of Sciences of the United States''. 2005. Volume 102. No. 11.]<br />
<br />
2. [http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=811162 Gilliland, S.E., Speck M.L. and Morgan, C.G. "The Detection of ''Lactobacillus acidophilus'' in Feces of Humans, Pigs and Chickens". ''Applied Microbiology''. October 1975. Pages 541-545. ]<br />
<br />
3. [http://www.blackwell-synergy.com/doi/full/10.1046/j.1365-2958.1999.01557.x Kullen, MJ and Klaenhammer, T.R. "Identification of the pH-inducible, proton-translocating F<sub>1</sub>F<sub>0</sub>ATPase (atpBEFHAGDC) operon of ''Lactobacillus acidophilus'' by differential disply; gene structure, cloning and characterization". ''Molecular Biology''. 1999. Volume 33. Pages 1152-1161.]<br />
<br />
4. [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E. and Klaenhammer, T.R. "The Scientific Basis of ''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331. ]<br />
<br />
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano</div>Jsamore