Query: NC_011026:1284966 Chloroherpeton thalassium ATCC 35110, complete genome
Lineage: Chloroherpeton thalassium; Chloroherpeton; Chlorobiaceae; Chlorobiales; Chlorobi; Bacteria
General Information: Chloroherpeton thalassium is a non-filamentous, flexing and gliding green sulfur bacterium isolated from marine sources off the North East coast of the USA in the 1980s. This organism is the most distant member of the green sulfur bacteria and is commonly found in aquatic microbial mats. Chloroherpeton thalassium is distinct from the other green sulfur bacteria in that it grows as a filamentous rod and is capable of gliding motility. Chloroherpeton thalassium is a photolithotroph, obtaining energy by anoxygenic photosynthesis using sulfide or sulfur as the electron donor. The photosynthetic apparatus consist of membrane-bound iron/sulfur reaction center associated with a light absorbing organelle, the chlorosome.
Subject: NC_004061:540354 Buchnera aphidicola str. Sg (Schizaphis graminum), complete genome
Lineage: Buchnera aphidicola; Buchnera; Enterobacteriaceae; Enterobacteriales; Proteobacteria; Bacteria
General Information: This strain is the symbiont of the aphid Schizaphis graminum and contains a large circular chromosome. Aphid endosymbiont. Almost all aphids contain maternally transmitted bacteriocyte cells, which themselves contain bacteria called Buchnera. The aphids live on a restricted diet (plant sap), rich in carbohydrates, but poor in nitrogenous or other essential compounds. It is believed that the Buchnera provide the essential nutrients the host lacks. Besides a nutritional co-dependence, due to a co-existence of millions of years, Buchnera have lost the ability to produce cell surface components such as lipopolysaccharides. This makes for an obligate endosymbiont relationship between host and Buchnera. Buchnera are prokaryotic cells which belong to the gamma-Proteobacteria, closely related to the Enterobacteriaceae family. Phylogenetic studies using 16S rRNA indicate that the symbiotic relationship was established around 200-250 million years ago. Since Buchnera are closely related to Escherichia coli and Haemophilus influenzae, comparative genomic studies can shed light on the evolutionary mechanisms of intracellular endosymbiosis as well as the different underlying molecular basis between organisms with parasitic behavior and symbionts.