Query: NC_004842:62000 Anaplasma marginale str. St. Maries, complete genome
Lineage: Anaplasma marginale; Anaplasma; Anaplasmataceae; Rickettsiales; Proteobacteria; Bacteria
General Information: This strain was recovered from an acutely infected cow from Northern Idaho, USA and bears an msp1a genotype of JBB. This strain is transmitted by ticks and is known to be virulent. This organism is the causative agent of bovine anaplasmosis and is an obligate intracellular pathogen. Transmission occurs via an arthropod vector (tick) and is a major problem in tropical regions where it causes severe morbidity in cattle populations. The bacterium lives intracellularly within membrane-bound vesicles in the host erythrocyte, a cell type which it specifically targets, resulting in severe anemia for the host organism.
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.