Query: NC_000912:107273 Mycoplasma pneumoniae M129, complete genome
Lineage: Mycoplasma pneumoniae; Mycoplasma; Mycoplasmataceae; Mycoplasmatales; Tenericutes; Bacteria
General Information: This strain is a clinical isolate from a patient with atypical pneumonia. This genus currently comprises more than 120 obligate parasitic species found in a wide spectrum of hosts, including humans, animals, insects and plants. The primary habitats of human and animal mycoplasmas are mucous membranes of the respiratory and urogenital tracts, eyes, mammary glands and the joints. Infection that proceeds through attachment of the bacteria to the host cell via specialized surface proteins, adhesins, and subsequent invasion, results in prolonged intracellular persistence that may cause lethality. Once detected in association with their eukaryotic host tissue, most mycoplasmas can be cultivated in the absence of a host if their extremely fastidious growth requirements are met.
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.