title: Medium- to large-sized xylo-oligosaccharides are responsible for xylanase induction in Prevotella bryantii B14.
abstract: Experiments were done to define the nature of the xylan-derived induction signal for xylanase activity, and evaluate which xylanase genes among the three known ones (xynA, xynB and xynC) are induced by the presence of xylan in Prevotella bryantii B(1)4. During the later stages of exponential growth on glucose, addition of 0.05 % water-soluble xylan (WS-X) stimulated xylanase formation within 30 min. Xylose, xylobiose, xylotriose, xylotetraose, xylopentaose, arabinose and glucuronic acid all failed to induce the xylanase activity. An acid-ethanol-soluble fraction of WS-X (approximate degree of polymerization 30) enhanced the activity significantly, whereas the acid-ethanol-insoluble fraction had no effect, unless first digested by the cloned P. bryantii XynC xylanase. These results indicate that medium- to large-sized xylo-oligosaccharides are responsible for induction. The transcription of all three known xylanase genes from P. bryantii was upregulated coordinately by addition of WS-X. There have been relatively few investigations into the regulation of xylanase activity in bacteria, and it appears to be unique that medium- to large-sized xylo-oligosaccharides are responsible for induction.
authors.affiliation: Laboratory of Animal Science, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
authors.forename: Kohji
authors.initials: K
authors.lastname: Miyazaki
authors.affiliation: Laboratory of Animal Science, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Hirase
authors.affiliation: Laboratory of Animal Science, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kojima
authors.affiliation: Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK.
authors.forename: Harry James
authors.initials: HJ
authors.lastname: Flint
mesh_terms: D004790:Enzyme Induction / Q000187:drug effects; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D005798:Genes, Bacterial; D009844:Oligosaccharides / Q000494:pharmacology*; D018720:Prevotella / Q000201:enzymology* / Q000235:genetics; D043325:Xylan Endo-1,3-beta-Xylosidase / Q000096:biosynthesis / Q000235:genetics; D014990:Xylans / Q000378:metabolism; D014995:Xylosidases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D009844:Oligosaccharides; D014990:Xylans; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase