Lactobacillus brevis
A Microbial Biorealm page on the genus Lactobacillus brevis
Classification
UNDER CONSTRUCTION
Higher order taxa
Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae; Lactobacillus
(domain; phylum; class; order; family; genus) NCBI
Species
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NCBI: Taxonomy |
Lactobacillus brevis
Description and significance
Describe the appearance, habitat, etc. of the organism, and why it is important enough to have its genome sequenced. Describe how and where it was isolated. Include a picture or two (with sources) if you can find them.
As a general overview, lactic acid bacteria which include the species Lactobacillus, are all Gram-positive organisms whose main metabolic pathway involves fermenting hexose sugars to produce lactic acid.
The significance of all lactic acid bacteria throughout history and until today is their metabolism which is used for preservations of foods and beverages. When strains of this bacteria were domesticated, their metabolic simplicity resulted in the ability to carry out fermentations for many of our modern foods. In fact, this bacteria plays a prominent part in the worlds food supply and production of some beers and wine.
Lactobacillus brevis is rod-shaped strain of lactic acid bacteria that can be found mainly in the intestinal flora and in soil. In general Lactobacilli are gram-positive and in nonsporeforming rods. Along with other lactic acid-producing bacteria, L. brevis plays an integral role in the fermentation of certain foods such as sauerkraut and pickles and is likewise the most common cause of spoiled beer. L. brevis can be isolated from the food sources in inhabits, one example being kimchi.
Genome structure
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?
Whole-genome sequencing was conducted at the U.S. Department of Energy for eight other species of Lactic acid bacteria the method used was shotgun sequencing, where different parts of a genome are sequenced and then the pieces were assembled. The completed genome of L. brevis shows that this bacteria is circular and has one chromosome with a length of 2.3 Mbp containing 2185 proteins and 82 RNAs. Two plasmids are also sequenced, much smaller in length, and have 11 and 12 proteins.
The evolution of Lactobacillales reveals a lot about the heritage of species and the ancestrol gene losses, and may suggest where duplications and the addidtion of new and unique genes occurred. One notable difference in L. brevis from the other species in this order, includes the loss of genes that carry out the biosynthesis of arginine and aromatic amino acids.
Cell structure and metabolism
Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.
L. brevis is a Gram-positive bacteria, thus implying a thick cell wall and an inner membrane in its rod shape. Although the sequenced genome of L. brevis is relatively small, the lactic acid bacteria can encode a multitude of different transporters to fulfill the needs of both prototrophic and auxotrophic strains.
Fermentation is the one most common pathway in L. brevis. The final product, lactic acid, is involved in the production of lactic acid, which contributes to production of such foods as cheese yogurt, fermented milks and others by inhibiting the growth of other organisms and lowering the pH of the products. Along the pathway, many metabolic reactions occur, one of them being the breakdown of milk products for cheese production. L. brevis specifically is used in industrial production to act as a starter culture for several types of beer and sourdough bread.
Ecology
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
One of the most interesting interaction is that with the human intestinal flora. Lactobacillus, when ingested, has probiotic effects as it improves the immune system. Most commonly however, this bacteria lives in the foods where it performs its metabolic pathways.
Pathology
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
L. brevis is not a pathogen and there are no cases where it has caused or contributed to disease in humans. In fact, it is the other way around. This bacteria is probiotic, and improves the human immune system.
Application to Biotechnology
Does this organism produce any useful compounds or enzymes? What are they and how are they used?
Current Research
Enter summaries of the most recent research here--at least three required
References
•http://img.jgi.doe.gov/cgi-bin/pub/main.cgi?section=TaxonDetail&page=taxonDetail&taxon_oid=639633027
•Proc Natl Acad Sci U S A. 2006 Oct 17;103(42):15611-6. Epub 2006 Oct 9.
•http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Retrieve&dopt=Overview&list_uids=404
•BIOLOGICAL SCIENCES / MICROBIOLOGY; Comparative genomics of the lactic acid bacteria. K. Makarovaa, A. Slesarevb, Y. Wolfa, A. Sorokina, B. Mirkinc, E. Koonina,d, A. Pavlovb, N. Pavlovab, V. Karamychevb, N. Polouchineb, V. Shakhovab, I. Grigorieve, Y. Loue, D. Rohksare, S. Lucase, K. Huange,f, D. M. Goodsteine, T. Hawkinse,f, V. Plengvidhyaf,g,h, D. Welkeri, J. Hughesi, Y. Gohj, A. Bensonj, K. Baldwink, J.-H. Leek, I. Díaz-Muñizf,l, B. Dostil, V. Smeianovl, W. Wechterf,l, R. Barabotem, G. Lorcaf,m, E. Altermannf,g, R. Barrangouf,g, B. Ganesann,o, Y. Xief,n,o, H. Rawsthornef,p, D. Tamirf,p,, C. Parkerf,p,, F. Breidtg,h, J. Broadbento, R. Hutkinsj, D. O'Sullivank, J. Steelel, G. Unluq, M. Saierm, T. Klaenhammerd,g, P. Richardsone, S. Kozyavkinb, B. Weimerd,n,o, and D. Millsd,p
• Wikipedia
• Bioresour Technol. 2007 May;98(8):1675-9. Epub 2006 Oct 18 [Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500. Edited by Ekaterina Magonova of Rachel Larsen and Kit Pogliano
