Lactobacillus acidophilus: Difference between revisions
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[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. ] | [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. ] | ||
[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.] | [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.] | ||
[http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E., Klaenhammer, T.R. "The Scientific Basis of''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331. ] | [http://jds.fass.org/cgi/reprint/84/2/319 Sanders, M.E., Klaenhammer, T.R. "The Scientific Basis of''Lactobacillus acidophilus'' NCFM Functionally as a Probiotic". ''Journal of Dairy Sciences''. 2001. Volume 84. Pages 319-331. ] | ||
Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano | Edited by [mailto:jennbs4@yahoo.com Jennifer B. Samore], student of [mailto:ralarsen@ucsd.edu Rachel Larsen] and Kit Pogliano |
Revision as of 04:36, 3 May 2007
Classification
Higher order taxa
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus
Species
Lactobacillus acidophilus
Strains
Laboratory: NCFM, 4962, CNRZ216, CNRZ218
Human: HA1, HA2, HA3, HM2, HM6
Pig: PA3, PA12, PA19, P18, P47
Chicken: C1, C2, C3, C7, C11
Description and significance
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.
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.
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.
Genome structure
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.
L. acidophilus NCFM contains no plasmids.
Cell structure and metabolism
L. acidophilus grows in low pH and anaerobic conditions.
An acid induced ATPase was identified in L. acidophilus. Based on primary structure and the genetic organization, it was further classified as a F1F0-type ATPase. Its similarity to the streptococcal ATPase and the H+ inducibility of the operon suggests that it is responsible for an ATP-dependent exclusion of protons in order to maintain cytoplasmic pH.
Ecology
Pathology
The exact mechanism of the probiotic effect is still under investigation.
One mechanism is based on competition for space in the GI tract. L. acidophilus has the ability to form a strong adherence to the GI tract which inhibits the adherence of other potentially harmful microbes.
Application to Biotechnology
Current Research
References
Edited by Jennifer B. Samore, student of Rachel Larsen and Kit Pogliano