Genetical and biochemical analyzes of multiple functions in filamentous fungi

在日本，以曲霉菌为代表的丝状真菌是发酵工业中重要的真核微生物。应用微生物学研究也表明，它们在许多领域具有相当价值和多种功能，有待进一步开发。在这个研究项目中，我们从遗传和生物化学的角度研究了过去三年在许多有用真菌中观察到的多种功能，以找出新的应用程序。本项目包括三个主题：1）有用酶的遗传和生化分析，2）有用酶的基因结构及其利用，3）基因表达和酶分泌的调控。1）有用酶的遗传和生化分析：在尼日尔曲霉中发现的胺氧化酶，在冬季毛霉中的内切-β-N-乙酰氨基葡糖苷酶，对高山被孢霉（Mortierella alpina）中参与不饱和脂肪酸合成的脂肪酸合成酶和酵母犁头霉（Absidia zychae）中参与不饱和脂肪酸合成的羧肽酶进行了详细的酶学性质研究，并克隆了部分酶的基因。有用酶的基因结构及其应用：尼日尔曲霉分泌的α-葡萄糖苷酶，微生物凝乳酶从分子水平上对微小根毛霉（Rhizomucor pusillus）胃蛋白酶、棘孢曲霉（Aspergillus aculeatus）的纤维素酶和参与氮代谢的酶进行了多方面的研究。基因表达和酶分泌的调节：已经在DNA水平上表征了构巢曲霉和少孢根霉中的凝乳蛋白合成酶。利用构巢曲霉作为中间宿主，对来源于曲霉的Taka-amylase A基因在基因表达水平上进行了表征。

Filamentous fungi represented by Aspergillus oryzae have been known to be important eukaryotic microorganisms in fermentation industries in Japan. It is also evident by applied microbiological researches that they have quite valuable and multiple functions to be exploited further in many fields. In this research project, we have studied for last three years multiple functions observed in many useful fungi from the genetical and biochemical points of view to find out novel their application procedure. This project comprise three topics : 1)genetical and biochemical analyzes of useful enzymes, 2)gene structures of useful enzymes and their utilization, 3)regulation of gene expression and enzyme secretion.1)genetical and biochemical analyzes of useful enzymes : amine oxydase found in Aspergillus niger, endo-beta-N-acetylglucosaminidase in Mucor hiemalis, fatty acid synthetases participated in the synthesis of unsaturated fatty acids in Mortierella alpina and carboxypeptidase in Absidia zychae have been characterized enzymologically in detail and some enzymes are cloned for thier genes.2)gene structures of useful enzymes and their application : alpha-glucosidase secreted from Aspergillus niger, microbial chymosin(Rhizomucor pusillus pepsin), cellulases from Aspergillus aculeatus and enzymes participated in the nitrogen metabolism are studied at molecular levels from various aspects.regulation of gene expression and enzyme secretion : chytin synthetases in Aspergillus nidulans and Rhizopus oligosporus have been characterised at DNA levels. Taka-amylase A genederived from Aspergillus oryzae has been characterized at the gene expression level using Aspergillus nidulans as an intermediate host.