Query: NC_008787:1463696 Campylobacter jejuni subsp. jejuni 81-176, complete genome
Lineage: Campylobacter jejuni; Campylobacter; Campylobacteraceae; Campylobacterales; Proteobacteria; Bacteria
General Information: This strain (81-176; Penner serotype 23/36) was isolated during an outbreak of campylobacteriosis in Minnesota, USA, due to the consumption of contaminated milk. This organism is the leading cause of bacterial food poisoning (campylobacteriosis) in the world, and is more prevalent than Salmonella enteritis (salmonellosis). Found throughout nature, it can colonize the intestines of both mammals and birds, and transmission to humans occurs via contaminated food products. This organism can invade the epithelial layer by first attaching to epithelial cells, then penetrating through them. Systemic infections can also occur causing more severe illnesses.
Subject: NC_004061:166375 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.