Query: NC_010513:2452811 Xylella fastidiosa M12 chromosome, complete genome
Lineage: Xylella fastidiosa; Xylella; Xanthomonadaceae; Xanthomonadales; Proteobacteria; Bacteria
General Information: Causal agent of citrus variegated chlorosis. This organism was first identified in 1993 as the causal agent of citrus variegated chlorosis, a disease that affects varieties of sweet oranges. This disease was first noticed in Brazil in 1987, and it greatly affects commercial orchards resulting in crop devastation worldwide. Other strains of this species cause a range of diseases in mulberry, pear, almond, elm, sycamore, oak, maple, pecan and coffee which collectively result in multimillion dollar devastation of economically important plants. The bacteria are transmitted from the gut of the insect vector (sharpshooter leafhopper) to the plant xylem (water conducting system) when the insect feeds. Xylella fastidiosa is similar to Xanthomonas campestris pv. campestris in that it produces a wide variety of pathogenic factors for colonization in a host-specific manner including a large number of fimbrial and afimbrial adhesins for attachment. It does not contain a type III secretion system, but possesses genes for a type II secretion system for export of exoenzymes that degrade the plant cell wall and allow the bacterium to colonize the plant xylem. The cell produces an exopolysaccharide that is similar to the xanthan gum produced by Xanthomonas campestris pv. campestris.
Subject: NC_008593:2527064 Clostridium novyi NT, complete genome
Lineage: Clostridium novyi; Clostridium; Clostridiaceae; Clostridiales; Firmicutes; Bacteria
General Information: This strain (NT) was created so that it lacks the lethal toxin. Injection of spores of this organism into mice harboring tumors resulted in an increased immune response and destruction of the tumor tissue in a method known as COBALT (combination bacteriolytic therapy) when the spores along with chemotherapeutic agents or radiation are co-administered. The anaerobic bacteria preferentially target hypoxic cancer tissue and stimulate immune responses to that tissue. 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. Some species are capable of producing organic solvents (acetone, ethanol, etc,), molecular hydrogen and other useful compounds. Clostridium novyi is an anaerobic bacterium found in soil, aquatic sediments, and intestinal tract of both animals and humans. Some types produce lethal toxins.