Complete genome of a new Firmicutes species belonging to the dominant human colonic microbiota (‘Ruminococcus bicirculans’) reveals two chromosomes and a selective capacity to utilize plant glucans

摘要: The recently isolated bacterial strain 80/3 represents one of the most abundant 16S rRNA phylotypes detected in healthy human large intestine and belongs to Ruminococcaceae family Firmicutes. completed genome sequence reported here is first for a member this important bacteria from colon. comprises two chromosomes 2.24 0.73 Mbp, leading us propose name Ruminococcus bicirculans new species. Analysis carbohydrate active enzyme complement suggests an ability utilize certain hemicelluloses, especially β-glucans xyloglucan, growth that was confirmed experimentally. enzymatic machinery enabling degradation cellulose xylan by related cellulolytic ruminococci however lacking While indicated capacity synthesize purines, pyrimidines all 20 amino acids, only genes synthesis nicotinate, NAD+, NADP+ coenzyme A were among essential vitamins co-factors, resulting multiple requirements. In vivo, these factors must be supplied diet, host or other gut microorganisms. Other features ecological interest include type IV pilins, extracytoplasmic function-sigma factors, urease bile salt hydrolase.