Chi Zhenming, Ma Liyan, Gao Lingmei, Duan Xiaohui
UNESCO Chinese Center of Marine Biotechnology, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Indian J Biochem Biophys. 2007 Jun;44(3):152-6.
The effect of inositol supplementation on glucose derepression, invertase secretion and SUC2 gene expression in Saccharomyces sp. W4 was studied. Invertase secretion was repressed, when the yeast cells, grown the synthetic medium without inositol (I(-) medium) contained more than 0.2% (w/v) initial concentration of glucose. However, in the same medium plus inositol (I(+) medium, inositol conc. 100 microg/100 ml), invertase secretion was repressed only at glucose concentrations higher than 2.0% (w/v). Results showed that secreted invertase activity increased only in the I+ medium, whereas intracellular invertase activity remained constant in both media during the cell, growth. The mRNA encoding secreted invertase was higher in the glucose-derepressed cells grown in the I(+) medium than in the glucose-repressed cells grown in the I(-) medium. Similarly, phosphatidylinositol (PI) content was significantly higher in the cells grown in the I(+) medium than in the I(-) medium. These results indicated that PI might be involved in the glucose derepression, invertase secretion and SUC2 gene expression at the transcriptional level in the yeast.
研究了补充肌醇对酿酒酵母W4中葡萄糖去阻遏、转化酶分泌及SUC2基因表达的影响。当在不含肌醇的合成培养基（I(-)培养基）中生长的酵母细胞初始葡萄糖浓度超过0.2%（w/v）时，转化酶分泌受到抑制。然而，在同一培养基中添加肌醇（I(+)培养基，肌醇浓度为100μg/100ml）后，仅在葡萄糖浓度高于2.0%（w/v）时转化酶分泌才受到抑制。结果表明，分泌型转化酶活性仅在I(+)培养基中增加，而在细胞生长过程中，两种培养基中的细胞内转化酶活性均保持恒定。在I(+)培养基中生长的葡萄糖去阻遏细胞中，编码分泌型转化酶的mRNA高于在I(-)培养基中生长的葡萄糖阻遏细胞。同样，I(+)培养基中生长的细胞中磷脂酰肌醇（PI）含量显著高于I(-)培养基中的细胞。这些结果表明，PI可能在酵母转录水平上参与葡萄糖去阻遏、转化酶分泌及SUC2基因表达。
