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81.
H. Bussey C. Boone H. Zhu T. Vernet M. Whiteway D. Y. Thomas 《Cellular and molecular life sciences : CMLS》1990,46(2):193-200
Summary The K1 killer toxin ofSaccharomyces cerevisiae is a secreted, virally-coded protein lethal to sensitive yeasts. Killer yeasts are immune to the toxin they produce. This killer system has been extensively examined from genetic and molecular perspectives. Here we review the biology of killer yeasts, and examine the synthesis and action of the protein toxin and the immunity component. We summarise the structure of the toxin precursor gene and its protein products, outline the proteolytic processing of the toxin subunits from the precursor, and their passage through the yeast secretory pathway. We then discuss the mode of action of the toxin, its lectin-like interaction with a cell wall glucan, and its probable role in forming channels in the yeast plasma membrane. In addition we describe models of how a toxin precursor species functions as the immunity component, probably by interfering with channel formation. We conclude with a review of the functional domains of the toxin structural gene as determined by site-directed mutagenesis. This work has identified regions associated with glucan binding, toxin activity, and immunity. 相似文献
82.
乔世伟 《青岛大学学报(自然科学版)》1999,12(2):62-67
研究了以精炼糖废蜜为原料,采用连续多级发酵制作酵母的工艺过程,确定出适用进糖浓度与最佳稀释率等工艺参数 相似文献
83.
应用食用菌深层液体发酵技术获得猴头,灵芝菌丝体发酵醪,再经胶体磨使细胞壁破碎后,与啤酒生产原料一起进行啤酒发酵而得猴头啤酒和灵芝啤酒。经检测,酒液中氨基酸总量分别为1617.6mg.L^-1和1511.5mg.L^-1,其中人体必需氨基酸分别占20.51%和25.35%。,其他各项指标均符合国家标准。 相似文献
84.
周少奇 《暨南大学学报(自然科学与医学版)》2000,21(1):25-28
用RheometricsRFSⅡ型流变仪对酵母渣泥的流变曲线(r-γ)和粘弹性进行测试;结果显示酵母废渣具有一定的粘弹性,其τ-γ流变曲线有复杂的弯曲形状.在25~35℃范围,当温度处于28~35℃区间时,表观粘度及弹性均随温度的升高而升高. 相似文献
85.
H. Riezman A. Munn M. I. Geli L. Hicke 《Cellular and molecular life sciences : CMLS》1996,52(12):1033-1041
Endocytosis is a general term that is used to describe the internalization of external and plasma membrane molecules into the cell interior. In fact, several different mechanisms exist for the internalization step of this process. In this review we emphasize the work on the actin-dependent pathways, in particular in the yeastSaccharomyces cerevisiae, because several components of the molecular machinery are identified. In this yeast, the analysis of endocytosis in various mutants reveals a requirement for actin, calmodulin, a type I myosin, as well as a number of other proteins that affect actin dynamics. Some of these proteins have homology to proteins in animal cells that are believed to be involved in endocytosis. In addition, the demonstration that ubiquitination of some cell surface molecules is required for their efficient internalization is described. We compare the actin, myosin and ubiquitin requirements for endocytosis with recent results found studying these processes usingDictyostelium discoideum and animal cells. 相似文献
86.
以K_2型嗜杀酵母为材料在改进Russell(1986)的嗜杀活性检测方法基础上,建立了双层平板单菌落检测法。此法可直接用于嗜杀酵母的筛选,嗜杀质粒的检测,并能在诱变后的平板上检出有嗜杀活性的营养缺陷型菌株MK_2-3:K~+,len。对K_2嗜杀特性初步研究表明,K_2型嗜杀酵母能杀死酿酒酵母(Saccha-romyces cerevisiae),但对所测汉逊酵母(Hansenula spp.)无作用。嗜杀毒素产生的最适pH和温度分别为pH4.5—5.5和20—25℃,酵母菌的对数生长期嗜杀毒素达到高峰。用紫外线(UV)、溴化乙锭(EB)、亚硝基胍(NTG)和甲基磺酸乙酯(EMS)进行消除K因子实验,表明亚硝基胍和紫外线对K因子具有一定消除率,而溴化乙锭和甲基磺酸乙酯未发现消除作用。 相似文献
87.
TENG Hu HUANG Xun XIU Zhilong FENG Enmin 《科学通报(英文版)》2005,50(17):1896-1903
Cell cycle is a programmed process, during which a cell proliferates to two daughter cells. The eukaryotic or-ganisms share the same characters, such as four cycle phases G1, S, G2 and M, the evolutionally conserved cell cycle proteins and its dependent kinases, and the check-points mechanism[1,2]. Due to the different functions and the complicated interactions of these proteins involved in cell cycle, it is very difficult to understand the regulatory mechanism of cell cycle in a whole sense … 相似文献
88.
羧基在酵母菌生物吸附铅时的作用 总被引:7,自引:0,他引:7
用不同方法研究了酵母菌吸附重金属的机理.电位滴定法的结果说明生物材料含有0.5 mmol/g的酸性基团;酯化后的酵母菌对重金属的吸附量显著下降.对酯化前后的生物材料的红外光谱进行了比较,1 744 cm-1的吸收峰强度的增加证明酵母菌发生了酯化过程.羧基在酵母菌结合铅时起重要作用. 相似文献
89.
采用紫外分光光度法对啤酒酵母中水溶性多糖的含量进行测定,发现啤酒酵母水溶性多糖在波长489nm处有最大吸收峰。葡萄糖浓度在1.55~13.286μg.mL-1(r=0.9989)范围内、线性关系良好,平均回收率在6.1%,RSD为2.3%。 相似文献
90.
The interaction between PⅡ and NifA in A.brasilense Sp7 was investigated by using the yeast two-hybrid system.Our experimental results showed that PⅡ directly interacted with the entire NifA protein and its N-terminal domain,but did not interact with the central domin and the C-terminal domain of NifA.No interaction happened if glnB coding for PⅡ was frame-shift mutated.Pz,a homolog of PⅡ,had no interation with NifA. 相似文献