Query: NC_001263:2236777 Deinococcus radiodurans R1 chromosome 1, complete sequence
Lineage: Deinococcus radiodurans; Deinococcus; Deinococcaceae; Deinococcales; Deinococcus-Thermus; Bacteria
General Information: This red-pigmented organism's name means "strange berry that withstands radiation", marking the fact that this organism is one of the most radiation-resistant known. It can tolerate radiation levels at 1000 times the levels that would kill a human and it was originally isolated in 1956 from a can of meat that had been irradiated with X-rays. The resistance to radiation may reflect its resistance to dessication, which also causes DNA damage. This organism may be of use in cleaning up toxic metals found at nuclear weapons production sites due to the radiation resistance. This bacterium is also a highly efficient transformer, and can readily take up exogenous DNA from the environment, which may also aid DNA repair. This organism carries multiple copies of many DNA repair genes, suggesting a robust system for dealing with DNA damage. The recombination system may rely on multiple copies of various repeat elements found throughout the genome.
Subject: NC_015571:2273503 Porphyromonas gingivalis TDC60, complete genome
Lineage: Porphyromonas gingivalis; Porphyromonas; Porphyromonadaceae; Bacteroidales; Bacteroidetes; Bacteria
General Information: This organism is associated with severe and chronic periodontal (tissues surrounding and supporting the tooth) diseases. Progression of the disease is caused by colonization by this organism in an anaerobic environment in host tissues and severe progression results in loss of the tissues supporting the tooth and eventually loss of the tooth itself. The black pigmentation characteristic of this bacterium comes from iron acquisition that does not use the typical siderophore system of other bacteria but accumulates hemin. Peptides appear to be the predominant carbon and energy source of this organism, perhaps in keeping with its ability to destroy host tissue. Oxygen tolerance systems play a part in establishment of the organism in the oral cavity, including a superoxide dismutase. Pathogenic factors include extracellular adhesins that mediate interactions with other bacteria as well as the extracellular matrix, and a host of degradative enzymes that are responsible for tissue degradation and spread of the organism including the gingipains, which are trypsin-like cysteine proteases.