Query: NC_017379:1035464 Helicobacter pylori Puno135 chromosome, complete genome
Lineage: Helicobacter pylori; Helicobacter; Helicobacteraceae; Campylobacterales; Proteobacteria; Bacteria
General Information: This genus consists of organisms that colonize the mucosal layer of the gastrointestinal tract or are found enterohepatically (in the liver). It was only recently discovered (1983) by two Australians (Warren and Marshall) that this organism was associated with peptic ulcers. It is one of the most common chronic infectious organisms, and is found in half the world's population. This organism attacks the gastric epithilial surface, resulting in chronic gastritis, and can cause more severe diseases including those that lead to gastric carcinomas and lymphomas, peptic ulcers, and severe diarrhea. It is an extracellular pathogen that persists in the gastric environment, which has a very low pH, by production of the urease enzyme, which converts urea to ammonia and carbon dioxide, a process which can counteract the acidic environment by production of a base. The toxins include cytolethal distending toxin, vacuolating cytotoxin (VacA) that induces host epithelial cell apopoptosis (cell death), and the cytotoxin associated antigen (CagA) which results in alteration to the host cell signalling pathways. The CagA protein is translocated into host cells by a type IV secretion system encoded by the cag pathogenicity island.
Subject: NC_007952:1293024 Burkholderia xenovorans LB400 chromosome 2, complete sequence
Lineage: Burkholderia xenovorans; Burkholderia; Burkholderiaceae; Burkholderiales; Proteobacteria; Bacteria
General Information: Originally identified as Pseudomonas sp. LB400 that was found in contaminated soil in upstate New York, USA, this organism is now classified in the genus Burkholderia. Polychlorinated biphenyl-degrading bacterium. Member of the genus Burkholderia are versatile organisms that occupy a surprisingly wide range of ecological niches. These bacteria are exploited for biocontrol, bioremediation, and plant growth promotion purposes. Burkholderia xenovorans has been found on fungi, animals, and from human clinical isolates such as from cystic fibrosis (CF) patients. It may be tightly associated with white-rot fungus, as the degadation of lignin by the fungus results in aromatic compounds the bacterium can then degrade. This organism is exceptionally capable of degradation of polychlorinated biphenyls (PCBs), which are environmental pollutants, and thus it may play a role in bioremediation of polluted and toxic sites and is studied as a model bioremediator. PCBs can be utilized as the sole carbon and energy source by this organism. The pathways for degradation of PCBs have been extensively characterized at both the genetic and the molecular level and have become a model system for the bacterial breakdown of these very persistent environmental contaminants.