Medium- to large-sized xylo-oligosaccharides are responsible for xylanase induction in Prevotella bryantii B14.
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.
Miyazaki
Kohji
K
Laboratory of Animal Science, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
Hirase
Tatsuaki
T
Laboratory of Animal Science, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
Kojima
Yoichi
Y
Laboratory of Animal Science, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
Flint
Harry James
HJ
Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK.
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
D009844:Oligosaccharides; D014990:Xylans; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase