Query: NC_007205:1059684 Candidatus Pelagibacter ubique HTCC1062, complete genome
Lineage: Pelagibacter ubique; Pelagibacter; Pelagibacteraceae; Rickettsiales; Proteobacteria; Bacteria
General Information: They were originally named SAR11 and known only from their rRNA genes, which were first identified in environmental samples from the Sargasso Sea in 1990. P. ubique are possibly the most numerous bacteria in the world.
Subject: NC_004545:15650 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.