Project description:Conventionally raised and germ-free newly weaned male Sprague-Dawley rats were fed a basal diet or a diet supplemented with digestion resistant carbohydrates in the form of inulin, resistant starch or konjac flour. Gene expression in colon tissue was measured to characterise interaction between food, microbes and host.
Project description:Fungal endo-β-mannanases (β-mannanases) are widely used as industrial enzymes; however, no transcriptional regulator of β-mannanases has been identified in fungi or other eukaryotic cells to date. To identify a transcriptional regulator of β-mannanases in Aspergillus oryzae, a gene-disruptant library of transcriptional regulators was screened for mutants exhibiting reduced β-mannanase activity by using konjac glucomannan as the substrate, and ManR, a Zn(II)2Cys6 type DNA binding protein was identified. Moreover, a manR-overexpressing strain showed significantly increased β-mannanase activity. DNA microarray analysis of the manR-disruptant strain and the manR-overexpressing strain further indicated that when konjac glucomannan is used as the carbon source, ManR positively regulates the gene expression of not only β-mannanase, but also the enzymes involved in the degradation of galactomannans and glucomannans such as α-galactosidase, β-mannosidase, acetylmannan esterase, and β-glucosidase. Therefore, we conclude that ManR is a positive regulator of the β-mannan utilization system in A. oryzae.