In ethanol fermentation of Saccharomyces cerevisiae (S. cerevisiae), glycerol is one of the main by-products. The purpose of this investigation was to increase ethanol yield through minimizing glycerol yield by usin...In ethanol fermentation of Saccharomyces cerevisiae (S. cerevisiae), glycerol is one of the main by-products. The purpose of this investigation was to increase ethanol yield through minimizing glycerol yield by using mutants in which FPS1 encoding a channel protein that mediates glycerol export and GPD2 encoding one of glycerol-3-phosphate dehydrogenase were knocked-out using one-step gene replacement. GLT1 and GLN1 that encode glutamate synthase and glutamine synth.etase, respectively,were overexpressed using two-step gene replacment in fpsl△gpd2△ mutant.The fermentation properties of ZAL69(fpsl△::LEU2 gpd2△::URA3) and ZAL808 (fps1△::LEU2 gpd2△::URA3 PPGK1-GLT1 PPGK1-GLN1) under microaerobic conditions were investigated and compared with those of wild type(DC124). Consumption of glucose, yield of ethanol, yield of glycerol, acetic acid, and pyruvic acid were monitored. Compared with wild type, the ethanol yield of ZAL69 and ZAL808 were improved by. 13.17% and 6.66 %, respectively, whereas glycerol yield decreased by 37.4 % and 41.7 %. Meanwhile, acetic acia yield and pyruvic acid yield aecreasea aramatlcally comparea to wild type. Our results indicate that FPS1 and GPD2 deletion of S. cerevisiae resulted in reduced glycerol yield and increased ethanol yield, but simultaneous overexpression of GLT1 and GLN1 infps1△gpd2△ mutant did not have a higher ethanol yield thanfps1△gpd2△ mutant.展开更多
目的:探讨X线修复交叉互补组1基因(X-ray repair cross complementing group 1,XRCC1)、人类着色性干皮病基因D(xeroderma pigmentosum complementary group D,XPD)多态性与喉癌遗传易感性的关系。方法:采用病例-对照设计方法对72例经...目的:探讨X线修复交叉互补组1基因(X-ray repair cross complementing group 1,XRCC1)、人类着色性干皮病基因D(xeroderma pigmentosum complementary group D,XPD)多态性与喉癌遗传易感性的关系。方法:采用病例-对照设计方法对72例经病理确诊的喉鳞状细胞癌患者(病理组)和随机抽取的72例非癌症患者为对照组,均进行一般资料问卷调查和抽取外周静脉血进行XRCC1-Arg399Gln、XPD-Lys751Gln多态性检测和聚合酶链反应-限制性片段长度多态性分析法(PCR-RFLP)检测。结果:与携带XRCC1-399野生型(Arg/Arg)个体相比,病例组XRCC1第399位密码子杂合型(Arg/Gln)及突变型(Gln/Gln)分布频率高于对照组(P<0.05),携带该基因型的个体喉癌的发病风险升高3.37(OR=3.37,95%,CI=1.69-6.70)倍;XPD-Lys751Gln各基因型差异2组间无统计学意义;交互作用分析显示,吸烟与不吸烟患者比较,携带XRCC1-399Arg/Gln+Gln/Gln基因型个体的喉癌发病风险差异未发现有统计学意义(χH2=0.09)。结论:XRCC1-399位点Arg→Gln的氨基酸替换可能导致喉癌的发病风险增加,XRCC1-Arg399Gln多态性可能与喉癌的遗传易感性有关。展开更多
基金the National High Technology Research and Development Program of China(2002AA647040)
文摘In ethanol fermentation of Saccharomyces cerevisiae (S. cerevisiae), glycerol is one of the main by-products. The purpose of this investigation was to increase ethanol yield through minimizing glycerol yield by using mutants in which FPS1 encoding a channel protein that mediates glycerol export and GPD2 encoding one of glycerol-3-phosphate dehydrogenase were knocked-out using one-step gene replacement. GLT1 and GLN1 that encode glutamate synthase and glutamine synth.etase, respectively,were overexpressed using two-step gene replacment in fpsl△gpd2△ mutant.The fermentation properties of ZAL69(fpsl△::LEU2 gpd2△::URA3) and ZAL808 (fps1△::LEU2 gpd2△::URA3 PPGK1-GLT1 PPGK1-GLN1) under microaerobic conditions were investigated and compared with those of wild type(DC124). Consumption of glucose, yield of ethanol, yield of glycerol, acetic acid, and pyruvic acid were monitored. Compared with wild type, the ethanol yield of ZAL69 and ZAL808 were improved by. 13.17% and 6.66 %, respectively, whereas glycerol yield decreased by 37.4 % and 41.7 %. Meanwhile, acetic acia yield and pyruvic acid yield aecreasea aramatlcally comparea to wild type. Our results indicate that FPS1 and GPD2 deletion of S. cerevisiae resulted in reduced glycerol yield and increased ethanol yield, but simultaneous overexpression of GLT1 and GLN1 infps1△gpd2△ mutant did not have a higher ethanol yield thanfps1△gpd2△ mutant.
文摘目的:探讨X线修复交叉互补组1基因(X-ray repair cross complementing group 1,XRCC1)、人类着色性干皮病基因D(xeroderma pigmentosum complementary group D,XPD)多态性与喉癌遗传易感性的关系。方法:采用病例-对照设计方法对72例经病理确诊的喉鳞状细胞癌患者(病理组)和随机抽取的72例非癌症患者为对照组,均进行一般资料问卷调查和抽取外周静脉血进行XRCC1-Arg399Gln、XPD-Lys751Gln多态性检测和聚合酶链反应-限制性片段长度多态性分析法(PCR-RFLP)检测。结果:与携带XRCC1-399野生型(Arg/Arg)个体相比,病例组XRCC1第399位密码子杂合型(Arg/Gln)及突变型(Gln/Gln)分布频率高于对照组(P<0.05),携带该基因型的个体喉癌的发病风险升高3.37(OR=3.37,95%,CI=1.69-6.70)倍;XPD-Lys751Gln各基因型差异2组间无统计学意义;交互作用分析显示,吸烟与不吸烟患者比较,携带XRCC1-399Arg/Gln+Gln/Gln基因型个体的喉癌发病风险差异未发现有统计学意义(χH2=0.09)。结论:XRCC1-399位点Arg→Gln的氨基酸替换可能导致喉癌的发病风险增加,XRCC1-Arg399Gln多态性可能与喉癌的遗传易感性有关。