【摘要】 通过原生质体融合或秋水仙素染色体加倍技术 ,构建成交配型位点基因纯合 (α/α)的二倍体 .对所获二倍体及其亲株的糖化酶酶活性进行测定 .结果表明 ,这 3个非连锁的糖化酶等效异位基因表现出显著的剂量效应 ,应用中 3株纯合二倍体CIY187 14 (STA3/STA3) ,SFY5 5 (STA2 /STA2 )和CI12C 6 6 (STA1/STA1)菌株 ,其酶活性分别是其亲株的 2 4 4 ,2 31和 2 31倍 ,说明利用糖化酶基因的剂量效应可以获得高酶活性的糖化酵母新菌株更多还原

【Abstract】 Diploid strains homozygous for both MTA and STA genes and Diploid strains homozygous for MTA genes but inter combinative for STA genes were constructed by means of the protoplast fusion and colchicine chromosome treatment The results of glucoamylase activity determination of the diploids obtained and their parents indicated that the gene dosage effect of these three unlinked polymeric genes coded glucoamylase is obvious.In practice the glucoamylase activity of three homozygons diploid strains CIY187 14(α/α,STA3/STA3),SFY5 5(α/α,STA2/STA2) and CI12C 66(α/α,STA1/STA1)were respectively 2 44,2 31 and 2 31 fold as compared with that of their haploid parent strains These experimental results also suggested that the new strain Saccharomyces diastaticus with high glucoamylase activity could be constructed using dosage effect of the glucoamylase genes更多还原