Query: NC_006142:140853 Rickettsia typhi str. Wilmington, 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. Rickettsia typhi causes murine typhus and is an obligate intracellular pathogen that infects both the flea vector and hosts such as human, rat, and mouse. In the flea vector, the bacterium penetrates the gut epithelial barrier and is found in the feces which become infective.
Subject: NC_012416:4973 Wolbachia sp. wRi, complete genome
Lineage: Wolbachia; Wolbachia; Anaplasmataceae; Rickettsiales; Proteobacteria; Bacteria
General Information: Endosymbiont. Obligate intracellular bacterium infects around 20% of all insect species. Naturally infects Drosophila simulans and induces almost complete cytoplasmic incompatibility in its host. Wolbachia sp. subsp. Drosophila simulans (strain wRi) is an intracellular proteobacterium that infect insects as well as isopods, spiders, scorpions, mites, and filarial nematodes. It is maternally inherited and induces reproductive alterations of insect populations by male killing, feminization, parthenogenesis, or cytoplasmic incompatibility. In insect populations, Wolbachia sp. induce reproductive manipulations to enhance their own spreading. The most frequently observed reproductive abnormality is cytoplasmic incompatibility, where uninfected females are unable to produce offspring with infected males, whereas infected females can produce offspring with both infected and uninfected males, thus creating a reproductive advantage for infected females. Other spectacular effects of Wolbachia sp. infections are male embryo killing, feminization, and parthenogenesis induction.