Query: NC_016929:851044 Rickettsia canadensis str. CA410 chromosome, complete genome
Lineage: Rickettsia canadensis; Rickettsia; Rickettsiaceae; Rickettsiales; Proteobacteria; Bacteria
General Information: Members of this genus, like other Rickettsial organisms such as Neorickettsia and Anaplasma, are obligate intracellular pathogens. In both groups, the bacteria are transmitted via an insect, usually a tick, to a host organism 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. This organism was originally thought to be a member of the typhus group of Rickettsiales, however, it is now thought to represent a distict group with the rickettsia.
Subject: NC_019771:2816732 Anabaena cylindrica PCC 7122, complete genome
Lineage: Anabaena cylindrica; Anabaena; Nostocaceae; Nostocales; Cyanobacteria; Bacteria
General Information: Country: United Kingdom; Environment: Ponds; Isolation: Water, most likely pond, Cambridge, UK, 1939; Temp: Mesophile. They form long filaments and can be found worldwide in various aquatic environments as well as some terrestrial ones. These bacteria can form a variety of differentiated cell types, including spore-like cells (akinetes), small motile filaments (hormongia) and most importantly, heterocysts that are nitrogen-producing cells. The heterocyst produces multiple layers outside of its cell wall, shuts down photosystem II in order to inhibit oxygenic photosynthesis and ramps up metabolism in order to use up the oxygen present. Heterocysts donate fixed nitrogen compounds as amino acids to neighboring cells and in return receive a photosynthetically produced carbon source such as sucrose. These organisms produce toxic blooms in aquatic environments that are harmful or fatal to animals and humans due to the various cyanotoxins they produce.