Query: NC_016933:1481000 Francisella tularensis TIGB03 chromosome, complete genome
Lineage: Francisella tularensis; Francisella; Francisellaceae; Thiotrichales; Proteobacteria; Bacteria
General Information: This organism was first identified by Edward Francis as the causative agent of a plague-like illness that affected squirrels in Tulare county in California in the early part of the 20th century. The organism now bears his name. The disease, which has been noted throughout recorded history, can be transmitted to humans by infected ticks or deerflies, infected meat, or by aerosol, and thus is a potential bioterrorism agent. This organism has a high infectivity rate, and can invade phagocytic and nonphagocytic cells, multiplying rapidly. Once within a macrophage, the organism can escape the phagosome and live in the cytosol. It is an aquatic organism, and can be found living inside protozoans, similar to what is observed with Legionella.
Subject: NC_004545:96422 Buchnera aphidicola str. Bp (Baizongia pistaciae), complete genome
Lineage: Buchnera aphidicola; Buchnera; Enterobacteriaceae; Enterobacteriales; Proteobacteria; Bacteria
General Information: This organism is found in the aphid Baizongia pistaciae. Aphid endosymbiont. 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.