Regulation of β-Xylosidase (Xy1A)Synthesis in Bacillus stearothermophilus

다국어 초록 (Multilingual Abstract)

Syntheses of the B. strearothermophilus xylanolytic enzymes such as xylanases, ?-xylosidases, ?-arabinofuranosidases, and esterases, were observed to be regulated by the carbon source present in the culture media. Xylan induced synthesis of ?-xylosidase at the highest level while xylose gave about 30% of the ?-xylosidase activity induced by xylan. The lowest syntheses of the xylanolytic enzymes above mentioned were detected in the basal medium containing glucose as a sole carbon source. When a mixture of xylan and glucose was used as a carbon source, we could observe glucose repression of xylanase (about 70-fold) and ?-xylosidase (about 40-fold) syntheses. Whereas, the level of the glucose repression of the expression of the xylA gene encoding the major ?-xylosidase of B. strearothermophilus was assessed to be about 10-fold when the relative amounts of the xylA transcript were determined. From the sequence of the xylA gene, we could find two CRE-like sequences (CRE-1 : nucleotides +124 to +136 and CRE-2: +247 to +259) within the reading frame of the xylA gene, either or both of which were suspected to be involved in catabolite repression of the xylA gene.

목차 (Table of Contents)

• Abstract
• INTRODUCTION
• MATERIALS AND METHODS
• RESULTS
• DISCUSSION
• Acknowledgements
• REFERENCES