Query: NC_014034:1507047 Rhodobacter capsulatus SB1003 chromosome, complete genome
Lineage: Rhodobacter capsulatus; Rhodobacter; Rhodobacteraceae; Rhodobacterales; Proteobacteria; Bacteria
General Information: This strain is a derivative strain isolated in the laboratory of Barry Marrs from the classical progenitor strain B10. It is rifampicin-resistant, produces GTA, and is capable of growing under high illumination (resistant to photooxidative killing). Bacteria belonging to the Rhodobacter group are metabolically versatile as they are able to use photosynthesis and usually can grow under both anaerobic and aerobic conditions. This organism is a facultatively phototrophic purple non-sulfur bacterium and the type species of the Rhodobacter group. The colony's color depends largely on the amount of oxygen present in its environment. While it is able to produce cellular energy in a number of different ways, it can rely on anoxygenic photosynthesis under anaerobic conditions in the presence of light. Some strains produce the Gene Transfer Element (GTA), a pro-phage particle capable of transferring genetic material between strains.
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.