Query: NC_010475:2896000 Synechococcus sp. PCC 7002, complete genome
Lineage: Synechococcus; Synechococcus; Synechococcaceae; Chroococcales; Cyanobacteria; Bacteria
General Information: The cyanobacterium Synechococcus sp. PCC 7002 (formerly known as Agmenellum quadruplicatum strain PR-6) was originally isolated in 1961 by Chase Van Baalen from an onshore, marine mud flat sample derived from fish pens on Maguyes Island, La Parguera, Puerto Rico. The organism grows in brackish (euryhaline/marine) water and is unicellular but tends to form short filaments of two to four cells during exponential growth at the temperature optimum of 38 degrees C. The strain is extremely tolerant of high light intensities and has been grown at light intensities equivalent to two suns. This unique combination of physiological and genetic properties have long made this strain an important model system to studies of the oxygenic photosynthetic apparatus, the regulation of carbon and nitrogen metabolism, and other aspects of cyanobacterial physiology and metabolism.
Subject: NC_010674:3674739 Clostridium botulinum B str. Eklund 17B, complete genome
Lineage: Clostridium botulinum; Clostridium; Clostridiaceae; Clostridiales; Firmicutes; Bacteria
General Information: Clostridium botulinum B str. Eklund 17B is a nonproteolytic botulism neurotoxin B strain. This strain was isolated from marine sediments taken off the coast of Washington, USA and was not associated with botulism. 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.