Query: NC_006055:689956 Mesoplasma florum L1, complete genome
Lineage: Mesoplasma florum; Mesoplasma; Entomoplasmataceae; Entomoplasmatales; Tenericutes; Bacteria
General Information: Isolated from the surface of the lemon tree flower. Bacterium which lacks a cell wall. This organism is a member of the Mollicutes which are bacteria that lack a cell wall and are obligately parasitic on a number of organisms including mammals, insects, and plants. Mesoplasma florum is a nonpathogenic organism and is nonmotile and is not closely related to Mycoplasma genitalium and Mycoplasma pneumoniae. Unlike other Mollicutes, this species does not require sterol to be supplied in the media for growth.
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.