Query: NC_006933:1051873 Brucella abortus biovar 1 str. 9-941 chromosome II, complete
Lineage: Brucella abortus; Brucella; Brucellaceae; Rhizobiales; Proteobacteria; Bacteria
General Information: Causes bovine brucellosis. They are highly infectious, and can be spread through contact with infected animal products or through the air, making them a potential bioterrorism agent. Once the organism has entered the body, it can become intracellular, and enter the blood and lymphatic regions, multiplying inside phagocytes before eventually causing bacteremia (spread of bacteria through the blood). Once the organism has entered the body, it can become intracellular, and enter the blood and lymphatic regions, multiplying inside phagocytes before eventually causing bacteremia (spread of bacteria through the blood). Virulence may depend on a type IV secretion system which may promote intracellular growth by secreting important effector molecules. This organism was first noticed on the island of Malta. It is the primary cause of bovine brucellosis, which results in enormous (billions of dollars) economic losses due primarily to reproductive failure and food losses. In man, it causes undulant fever, a long debilitating disease that is treated by protracted administration of antibiotics.
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.