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Roseburia inulinivoransRANK: SpeciesTAXONOMY: Terrabacteria group -> Firmicutes -> Clostridia -> Clostridiales -> Lachnospiraceae -> Roseburia -> Roseburia inulinivorans OVERVIEW: N.L. n. inulinum, inulin; L. part. adj. vorans, devouring; N.L. part. adj. inulinivorans, inulin-devouring, referring to the ability to use inulin as a growth substrate. Identified as constituent of vaginal microbiome. [PMID:23282177] Roseburia inulinivorans is a recently identified motile representative of the Firmicutes that contributes to butyrate formation from a variety of dietary polysaccharide substrates in the human large intestine. A cluster of fructo-oligosaccharide/inulin utilization genes induced during growth on inulin included one encoding a β-fructofuranosidase protein that was prominent in the proteome of inulin-grown cells. This cluster also included a 6-phosphofructokinase and an ABC transport system, whereas a distinct inulin-induced 1-phosphofructokinase was linked to a fructose-specific phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS II transport enzyme). Real-time PCR analysis showed that the β-fructofuranosidase and adjacent ABC transport protein showed greatest induction during growth on inulin, whereas the 1-phosphofructokinase enzyme and linked sugar phosphotransferase transport system were most strongly up-regulated during growth on fructose, indicating that these two clusters play distinct roles in the use of inulin. The R. inulinivorans β-fructofuranosidase was overexpressed in Escherichia coli and shown to hydrolyze fructans ranging from inulin down to sucrose, with greatest activity on fructo-oligosaccharides. Genes induced on starch included the major extracellular α-amylase and two distinct α-glucanotransferases together with a gene encoding a flagellin protein. The latter response may be concerned with improving bacterial access to insoluble starch particles. [PMID: 20679207] At the species level, butyrate-producing bacterial species, such as Blautia faecis, Roseburia inulinivorans, Ruminococcus torques, Clostridium lavalense, Bacteroides uniformis and Faecalibacterium prausnitzii were significantly reduced in Crohn's disease patients as compared to healthy individuals (p < 0.05). [PMID: 26789999 ] This species has been identified as a resident in the human gastrointestinal tract based on the phylogenetic framework of its small subunit ribosomal RNA gene sequences.[PMC 4262072] |