Query: NC_008555:2628858 Listeria welshimeri serovar 6b str. SLCC5334, complete genome
Lineage: Listeria welshimeri; Listeria; Listeriaceae; Bacillales; Firmicutes; Bacteria
General Information: Nonpathogenic bacterium. This organism is a nonpathogenic Listeria found in soil, water, food, and sewage. First isolated from decaying plants. L. welshimeri bacteria are small (0.5 to 2.0 μm), non-spore-forming, gram-positive rods which are motile below 30°C by means of peritrichous flagella.
Subject: NC_015662:385461 Buchnera aphidicola (Cinara tujafilina) chromosome, complete
Lineage: Buchnera aphidicola; Buchnera; Enterobacteriaceae; Enterobacteriales; Proteobacteria; Bacteria
General Information: 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.