Query: NC_010337:2339056 Heliobacterium modesticaldum Ice1, complete genome
Lineage: Heliobacterium modesticaldum; Heliobacterium; Heliobacteriaceae; Clostridiales; Firmicutes; Bacteria
General Information: Heliobacterium modesticaldum strain Ice1, the type strain of this species, was isolated from Icelandic hot spring volcanic soils. It grows optimally above 50 degrees Celsius, grows best photoheterotrophically, but can grow in the dark chemotrophically on pyruvate. Phototrophic thermophile. This organism is an anoxygenic phototroph isolated from hot spring microbial mats and volcanic soil. Cell wall structure, the ability to form endospores, and 16S ribosomal RNA analysis place Heliobacterium modesticaldum in a family of phototrophic bacteria related to the Clostridia. Heliobacterium modesticaldum is able to fix nitrogen and may contribute significantly to the nitrogen availability in microbial mats.
Subject: NC_010117:1461502 Coxiella burnetii RSA 331, complete genome
Lineage: Coxiella burnetii; Coxiella; Coxiellaceae; Legionellales; Proteobacteria; Bacteria
General Information: This strain (RSA 331; Hentzerling) is associated with acute Q fever and was isolated from the blood of an infected patient in northern Italy in 1945. This organism is widely distributed in nature and can cause infections in reptiles, birds, and mammals. It causes Q fever, or 'query' fever, an atypical pneumonia first associated with abattoir workers in Australia. Transmission may be through insect vectors such as ticks that have bitten an infected wild or domesticated animal, or through an aerosol produced by domesticated animals such as sheep or cattle. The presence of a plasmid is believed to be associated with virulence and pathogenicity, however C. burnetii isolates containing plasmid QpDG are avirulent in guinea pigs and plasmidless isolates have been associated with endocarditis in humans. Coxiella burnetii has a developmental life cycle, and can grow vegetatively through binary fission, or asymmetrically and produce a spore-like cell. The spore-like cell may enable the organism to exist extracellularly for small amounts of time. This bacterium is an obligate intracellular pathogen. It is endocytosed by a host cell, a macrophage for example, and lives and replicates inside the phagolysozome, a unique property of this organism. The genome encodes proteins that have a higher than average pI, which may enable adaptation to the acidic environment of the phagolysozome. The chromosome also contains genes for a number of detoxification and stress response proteins such as dismutases that allow growth in the oxidative environment. The type IV system is similar to the one found in Legionella, which may be important for intracellular survival. This organism produces numerous ankyrin-repeat proteins that may be involved in interactions with the host cell. The genome has 83 pseudogenes, which may be a result of the typical genome-wide degradation observed with other intracellular organisms and also has a group I intron in the 23S ribosomal RNA gene.