Query: NC_010162:573709 Sorangium cellulosum 'So ce 56', complete genome
Lineage: Sorangium cellulosum; Sorangium; Polyangiaceae; Myxococcales; Proteobacteria; Bacteria
General Information: Sorangium cellulosum 'So ce 56' produces a large number of bioactive compounds, such as, the antifungal soraphen and the anticancer agent epothilone. This organism, like other myxobacteria, undergoes a complex development and differentiation pathway. When cell density increases, the organism switches to "social motility" where aggregates of cells can gather together into masses termed fruiting bodies that may consist of up to 100 000 cells. The motility system is not dependent on flagella like most bacteria, but instead relies on twitching pili: short extracellular appendages that may function analogously to oars in a rowboat. The myxobacteria have proved to be a rich source of novel natural products. Sorangium cellulosum produces a number of antibacterial, antifungal and cytotoxic substances which are being studies for therapeutic applications.
Subject: NC_004061:31500 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.