有机化学品对酵母菌生物毒性的检测技术

采用酵母菌作为指示生物,研究了有机化学品生物毒性检测方法．在酵母菌毒性检测试验中,选择了5种有机溶剂及其混合溶剂进行了酵母菌抑制试验和对有机化学品溶解性试验．结果显示,V二甲亚砜“V甘油=6．6：3．4混合溶剂对酵母菌抑制最小,同时对大多数有机化学品具有较好溶解性能．应用二甲亚砜-甘油混合溶剂试验了几种有机化学品对酵母菌的生物毒性,并根据最小产生清晰抑菌圈浓度Cmiz评价了这几种有机化学品的生物毒性、该方法为建立定量构效关系(QSAR)模型奠定了生物学检测基础。     

嗜热厌氧产乙醇杆菌乙醇代谢途径的初步研究

以乙醇产量和细胞密度的提高为目标,从碳源和氮源入手,对嗜热厌氧产乙醇杆菌THermoanaerobacter ethanolicus JW200的培养基作了初步优化以提高乙醇代谢途径中的关键酶的得率,便于提纯.葡萄糖浓度的提高对乙醇的产生有明显的诱导作用,但当葡萄糖浓度高于2%,乙醇产量反而下降.酵母粉对乙醇产量没有促进作用,单纯提高酵母粉浓度对细胞密度无显著影响,而同时提高葡萄糖和酵母粉浓度至2.0%,OD600最高可达2.0.2%葡萄糖,0.5%酵母粉对单位细胞乙醇产量的诱导效果最佳.T.ethanolicusJW200粗酶液中未检测到丙酮酸脱羧酶的活性,经亲和柱Cibacron Blue-3GA部分纯化,在NAD洗脱蛋白中检测到辅酶A依赖型乙醛脱氢酶的活性,表明辅酶A依赖型乙醛脱氢酶是该菌乙醇代谢途径中的关键酶,它和乙醇脱氢酶共同作用,将乙酰辅酶A转化成乙醇.     

酵母培养液中胰蛋白酶初探

利用鸡卵黏蛋白对于胰蛋白酶有天然抑制性的特点,从鸡蛋清中分离纯化了鸡卵黏蛋白,将其偶联至Sepharose 4B制作成亲和层析介质,用于从不同种类酵母,处于不同时间段的培养液中,分离纯化得到了具有胰蛋白酶活性的物质。由此初步证明了酵母培养液中确有可能存在胰蛋白酶。因此,利用酵母工程菌生产蛋白质的时候,若加入一定量的胰蛋白酶抑制剂,有可能提高目的蛋白的产率。     

酵母胞外槐糖脂产生条件优化及其抑菌作用

通过单因子试验和正交试验对筛选得到的1株未见报道的产胞外槐糖脂的酵母菌Y2A菌株的培养基组成及培养条件进行了优化,结果表明,优化的最适产槐糖脂培养基配方为：质量分数6．0％葡萄糖、体积分数8．0％菜子油、质量分数0．2％酵母粉;优化后发酵条件为：初始pH值6．0、接种量体积分数2．5％、发酵时间120h,在此条件下,槐糖脂产量达到39．4g/L,然后发酵液经分离纯化并制备,得到纯品槐糖脂,将槐糖脂进行抑菌试验的研究结果表明,它对某些试验菌株的生长有抑制作用。     

Killer酵母筛选及其生理特性的研究

从自然界中筛选出一株Ｋｉｌｌｅｒ酵母６Ｂ２，对Ｋ酵母具有杀伤能力，同时对６Ｂ２野生酵母的生理特性进行了初步研究，发现该菌不仅具有样伤其他它酵母的能力，而且经发酵后可产生一类的香味物质。     

Electrochemical evaluation of the inhibitory effects of acetic acid on Saccharomyces cerevisiae

0 Introduction Fuel ethanol can be produced fromlignocellulose by chemical hydrolysis of lignocellulosic materialsfollowed by fermentation.One of the major problems with hydrolysates produced by acid hydrolysis is the poor fermentability caused by the presence of inhibitors in the hy- drolysates[1].Acetic acidis one of the most important in- hibitors .It is abundant due tothe deacetylation of xylose andthe breakdown of lignin[2]. The inhibitory effects of acetic acid on different yeast strain…     

RIG-G基因在酵母双杂交后的蛋白互作验证

RIG－G基因是利用全反式维甲酸（ATRA）诱导，采用差异显示PCR方法从APL细胞系NB4中克隆到的一个新基因。采用酶母双杂交的方法筛到了与RIG－G发生相互作用的JAB1。由于在酵母这种低等真核细胞中缺少诸如高等真核细胞中各种保证蛋白正常生物学功能发挥所必需的翻译后修饰，这种方法筛到的阳性克隆并不一定代表了真实的作用，所以在COS7细胞中采用了CO－IP（co-immunoprecipitation）实验，间接法、直接法均证实了这种相互作用。     

无机盐在酵母菌净化玉米淀粉工业废水中的作用

玉米淀粉工业废水是高浓度有机废水，在利用酵母菌净化此废水的研究试验中，向废水中添加无机盐，可明显提高其净化效率。     

Expression of the Stp1 LMW-PTP and inhibition of protein CK2 display a cooperative effect on immunophilin Fpr3 tyrosine phosphorylation and <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> growth

Although the yeast genome does not encode bona fide protein tyrosine kinases, tyrosine-phosphorylated proteins are numerous, suggesting that besides dual-specificity kinases, some Ser/Thr kinases are also committed to tyrosine phosphorylation in Saccharomyces cerevisiae. Here we show that blockage of the highly pleiotropic Ser/Thr kinase CK2 with a specific inhibitor synergizes with the overexpression of Stp1 low-molecular-weight protein tyrosine phosphatase (PTP) in inducing a severe growth-defective phenotype, consistent with a prominent role for CK2 in tyrosine phosphorylation in yeast. We also present in vivo evidence that immunophilin Fpr3, the only tyrosine-phosphorylated CK2 substrate recognized so far, interacts with and is dephosphorylated by Spt1. These data disclose a functional correlation between CK2 and LMW-PTPs, and suggest that reversible phosphorylation of Fpr3 plays a role in the regulation of growth rate and budding in S. cerevisiae.Received 15 January 2004; received after revision 20 February 2004; accepted 4 March 2004     

Conformational change of glutathione-S-transferase by its co-expression with prion domain of yeast Ure2p

Ure2 protein from Saccharomyces cerevisisae has a changeable structure similar to that ofrnammalian prion protein. Its N-terminal is the prion domain (PrD) consisting of 65 amino acids which plays a critical role in yeast prion development. In this study, PrD gene was recombinated with glutathione-S-transferase(GST) gene, and a soluble GST-PrD(sGST-PrD) fusion protein was expressed in E. coli. sGST-PrD could spontaneously polymerize into amyloid fibrils in vitro, displaying typical β-sheet-type structure; it had increased resistance to proteinase K and exhibited amvloid-like optical properties. Moreover, the aggregated GST-PrD(aGST-PrD) could induce sGST-PrD to aggregate into fibrils. These results indicate that PrD could change the conformation of GST moiety in a recombinant protein with PrD to form a prion-like chimeric protein, which proves that PrD has the ability to mediate a prion-like conversion of other proteins fused with it.