Query: NC_014228:3022903 Xenorhabdus nematophila ATCC 19061, complete genome
Lineage: Xenorhabdus nematophila; Xenorhabdus; Enterobacteriaceae; Enterobacteriales; Proteobacteria; Bacteria
General Information: This genus is a group of insect pathogens which live in a mutualistic relationship with the soil nematode family, Steinernematidae. Free-living, juvenile Steinernema spp. enter insect larvae through the digestive tract. They penetrate the larvae body cavity and release Xenorhabdus spp. into the hemolymph (blood). The bacteria multiply rapidly, killing the larvae, and providing suitable nutrient conditions for the growth and reproduction of the Steinernema spp. The nematode matures and reproduces. The new juveniles reassociate with Xenorhabdus spp. and are released into the soil. Unlike Xenorhabdus bovienii, which is found in different Steinernema spp., Xenorhabdus nematophila is associated specifically with Steinernema carpocapsae and can be used as a model for studying host specificity.
Subject: NC_012560:3771861 Azotobacter vinelandii DJ, complete genome
Lineage: Azotobacter vinelandii; Azotobacter; Pseudomonadaceae; Pseudomonadales; Proteobacteria; Bacteria
General Information: This organism was first isolated from the soil in Vineland, New Jersey, although it is found worldwide. It is a large obligate aerobe that has one of the highest respiratory rates of any organism. Azotobacter vinelandii also produces a number of unusual nitrogenases which allow it to fix atmospheric nitrogen to ammonia, a compound it can then use as a nitrogen source. It protects the oxygen-sensitive nitrogenase enzymes through its high respiratory rate, which sequesters the nitrogenase complexes in an anoxic environment. This organism has a number of unusual characteristics. Under extreme environmental conditions, the cell will produce a cyst that is resistant to dessication and is surrounded by two capsular polysaccharide layers. This organism produces two industrially important polysaccharides, poly-beta-hydroxybutyrate (PHB) and alginate. PHB is a thermoplastic biopolymer, and alginate is used in the food industry. Alginate is also used by the pathogen Pseudomonas aeruginosa to infect the lungs of cystic fibrosis patients.