Lactobacillus johnsonii NCC 533

Lactobacilli produce lactic acid and are used for many different things, including yogurt production and the maintenance of healthy intestinal microflora. Lactobacilli are commonly associated with the gastrointestinal tract of humans. The genome of the Lactobacillus plantarum has been sequenced and the genomes of several other Lactobacilli are underway. The goal of researchers is to better understand the roles, capabilities, and interactions of Lactobacilli.The genome of Lactobacillus plantarum has been sequenced. The genome is 3,308,274 bp long with 3,052 open-reading frames, and a G+C content of 44.5%. L. plantarum occupies many different niches in the environment including the human gastrointestinal tract. L. plantarum is very ecologically flexible as is reflected in the fact that it has one of the largest genomes of any of the lactic acid bacteria.The genome of Lactobacillus bulgaricus, which is currently in progress, is about 2.3 Mbp long with a G+C content of 50%. L. bulgaricus is one of the two bacteria required for the production of fermented milk and yogurt. The complete sequence of this genome will provide better understanding and control of this bacterium in the fermentation process.Lactobacilli are rod-shaped, Gram-positive, fermentative, organotrophs. They are usually straight, although they can form spiral or coccobacillary forms under certain conditions. They are often found in pairs or chains of varying length. Lactobacilli are classified as lactic acid bacteria, and derive almost all of their energy from the conversion of glucose to lactate during homolactic fermentation. In this process 85-90% of the sugar utilized is converted to lactic acid. They generate ATP by nonoxidative substrate-level phosphorylation.Lactobacilli are commonly associated with plant herbage. They have a generation time ranging from 25 minutes to several hundred minutes, and grow optimally between the temperatures of 30 and 40 degrees Celsius, although thermophilic strains can be comfortable at temperatures as high as 45 degrees Celsius. They are also commonly associated with the gastrointestinal tract of animals and humans. As natural GI microflora they are believed to perform several beneficial roles including immunomodulation, interference with enteric pathogens, and maintenance of healthy intestinal microflora. Lactobacillus gasseri appears to be the main species of lactobacilli that inhabits the human gastrointestinal tract. (From http://microbewiki.kenyon.edu/index.php/Lactobacillus) (MicrobeWiki: Lactobacillus)