Query: NC_007576:471500 Lactobacillus sakei subsp. sakei 23K, complete genome
Lineage: Lactobacillus sakei; Lactobacillus; Lactobacillaceae; Lactobacillales; Firmicutes; Bacteria
General Information: This strain (23K) was originally isolated from a French sausage. They are commonly found in the oral, vaginal, and intestinal regions of many animals. They are important industrial microbes that contribute to the production of cheese, yogurt, and other products such as fermented milks, all stemming from the production of lactic acid, which inhibits the growth of other organisms as well as lowering the pH of the food product. Industrial production requires the use of starter cultures, which are carefully cultivated, created, and maintained, which produce specific end products during fermentation that impart flavor to the final product, as well as contributing important metabolic reactions, such as the breakdown of milk proteins during cheese production. The end product of fermentation, lactic acid, is also being used as a starter molecule for complex organic molecule syntheses. Lactobacillus sakei is the predominant lactic acid bacteria found on fresh meat. This organism is used as a starter in the production of fermented meat products, and plays a major role in preserving meat products by inhibiting the growth of other bacteria.
Subject: NC_010723:485874 Clostridium botulinum E3 str. Alaska E43, complete genome
Lineage: Clostridium botulinum; Clostridium; Clostridiaceae; Clostridiales; Firmicutes; Bacteria
General Information: This strain was probably isolated from salmon eggs associated with a foodborne case of botulism in Alaska, however the exact details are not available. This genus comprises about 150 metabolically diverse species of anaerobes that are ubiquitous in virtually all anoxic habitats where organic compounds are present, including soils, aquatic sediments and the intestinal tracts of animals and humans. This shape is attributed to the presence of endospores that develop under conditions unfavorable for vegetative growth and distend single cells terminally or sub-terminally. Spores germinate under conditions favorable for vegetative growth, such as anaerobiosis and presence of organic substrates. It is believed that present day Mollicutes (Eubacteria) have evolved regressively (i.e., by genome reduction) from gram-positive clostridia-like ancestors with a low GC content in DNA. This organism produces one of the most potent and deadly neurotoxins known, a botulinum toxin that prevents the release of acetylcholine at the neuromuscular junction, thereby inhibiting muscle contraction and causing paralysis. In most cases the diseased person dies of asphyxiation as a result of paralysis of chest muscles involved in breathing. The spores are heat-resistant and can survive in inadequately heated, prepared, or processed foods. Spores germinate under favorable conditions (anaerobiosis and substrate-rich environment) and bacteria start propagating very rapidly, producing the toxin.Botulinum toxin, and C. botulinum cells, has been found in a wide variety of foods, including canned ones. Almost any food that has a high pH (above 4.6) can support growth of the bacterium. Honey is the most common vehicle for infection in infants. Food poisoning through C. botulinum is the most frequent type of infection caused by this bacterium. The wound botulism that occurs when C. botulinum infects an individual via an open wound is much rarer and is very similar to tetanus disease. There are several types of botulinum toxin known (type A through type F), all of them being neurotoxic polypeptides. The most common and widely distributed are strains and serovars of C. botulinum that produce type A toxin.