Query: NC_017066:243913 Rickettsia typhi str. TH1527 chromosome, complete genome
Lineage: Rickettsia typhi; Rickettsia; Rickettsiaceae; Rickettsiales; Proteobacteria; Bacteria
General Information: This genus, like other Rickettsial organisms such as Neorickettsia and Anaplasma, is composed of obligate intracellular pathogens. The latter is composed of two organisms, Rickettsia prowazekii and Rickettsia typhi. The bacteria are transmitted via an insect, usually a tick, to a host organism, in this case humans, where they target endothelial cells and sometimes macrophages. They attach via an adhesin, rickettsial outer membrane protein A, and are internalized where they persist as cytoplasmically free organisms. Transovarial transmission (from mother to offspring) occurs in the invertebrate host. This organism causes murine typhus and is an obligate intracellular pathogen that infects both the flea vector and hosts such as human, rat, and mouse. R. prowazekii, and genomic comparisons demonstrate colinearity and similarity to the genome of that organism except for two independent inversions near the origin and terminus. In the flea vector, the bacterium penetrates the gut epithelial barrier and is found in the feces which become infective.
Subject: NC_011959:972798 Thermomicrobium roseum DSM 5159, complete genome
Lineage: Thermomicrobium roseum; Thermomicrobium; Thermomicrobiaceae; Thermomicrobiales; Chloroflexi; Bacteria
General Information: Thermomicrobium roseum DSM 5159 was isolated from Yellowstone National Park, USA. Obligate thermophile with unusual cell wall structure. Thermomicrobium roseum is a red-pigmented, rod-shaped, Gram-negative extreme thermophile that possesses both an atypical cell wall composition and an unusual cell membrane that is composed entirely of long-chain 1,2-diols. Analyses of environmental sequences from hot spring environments show that T.roseum displays a low quantity but ubiquitous presence in top layers of microbial mats. Few standard housekeeping genes are found on the megaplasmid, however, it does encode a complete system for chemotaxis including both chemosensory components and an entire flagellar apparatus. T. roseum oxidizes CO aerobically, making it the first thermophile known to do so. In addition, is is propose that glycosylation of its carotenoids plays a crucial role in the adaptation of the cell membrane to this bacterium's thermophilic lifestyle. Because T. roseum is a deep-branching member of this phylum, eventhough this species is not photosynthetic, analysis of the genome provides some insight into the origins of photosynthesis in the Chloroflexi.