Immunogenicity and protective efficacy of yeast extracts containing rotavirus-like particles: A potential veterinary vaccine

Rotavirus is the most common cause of severe diarrhea in many animal species of economic interest. A simple, safe and cost-effective vaccine is required for the control and prevention of rotavirus in animals. In this study, we evaluated the use of Saccharomyces cerevisiae extracts containing rotavirus-like particles (RLP) as a vaccine candidate in an adult mice model. Two doses of 1 mg of yeast extract containing rotavirus proteins (between 0.3 and 3 μg) resulted in an immunological response capable of reducing the replication of rotavirus after infection. Viral shedding in all mice groups diminished in comparison with the control group when challenged with 100 50% diarrhea doses (DD₅₀) of murine rotavirus strain EDIM. Interestingly, when immunizing intranasally protection against rotavirus infection was observed even when no increase in rotavirus-specific antibody titers was evident, suggesting that cellular responses were responsible of protection. Our results indicate that raw yeast extracts containing rotavirus proteins and RLP are a simple, cost-effective alternative for veterinary vaccines against rotavirus.     

Schizosaccharomyces pombe: A novel transport vehicle of functional DNA and mRNA into mammalian antigen-presenting cells

Vaccine vehicles based on recombinant yeasts have become promising candidates for the induction of cellular immune responses. In this study, we investigated the capacity of the fission yeast Sz. pombe for the delivery of functional nucleic acids into murine and human antigen-presenting cells. We demonstrate that Sz. pombe cells effectively induce maturation of human dendritic cells (DC), an important prerequisite for T-cell activation. Further, recombinant fission yeast efficiently delivers functional DNA and mRNA into murine macrophages and human DC resulting in the expression of the model antigen eGFP in these cells. Thus, Sz. pombe suggests itself as a promising candidate for a novel live vaccine.     

酵母双杂交系统筛选CLN8P相互作用蛋白

目的：应用酵母双杂交系统筛选CLN8P相互作用蛋白质,通过对相互作用蛋白质的筛选及研究,探讨CLN8的功能,为NCL8和NCLs疾病群的发病机制研究提供线索,并为疾病的蛋白质相互作用网络提供资料。方法 应用酵母双杂交技术,以pLexA-CLN8为诱饵质粒筛选人胎脑cDNA文库,得到Leu+LacZ+阳性克隆,进一步进行验证,并对验证后的阳性克隆的外源性片断进行测序及同源性分析。结果 从人胎脑cDNA文库中筛选得到60个Leu+LacZ+阳性克隆;将获得的具有外源性片段的文库质粒与诱饵质粒一对一重新转入酵母体内对相互作用进行验证,共获得阳性克隆22个;对验证后阳性克隆测序并进行同源性分析,共获得不同的候选基因序列10个。结论 应用酵母双杂交系统,共筛选得到10个不同的基因,其编码蛋白与CLN8P有相互作用,可能与NCLs 发病机制相关。     

MIF活性区域相互作用蛋白的筛选

目的: 筛选与巨噬细胞移动抑制因子(MIF)催化巯基蛋白质氧化还原酶(TPOR)活性域相互结合的蛋白。方法: 采用酵母双杂交系统进行筛选。首先构建pBTM116-MIF诱饵质粒,转化酵母菌株L40;将表达MIF催化 TPOR活性域的L40酵母菌株制备成感受态菌,在人骨肉瘤cDNA文库中筛选。通过组氨酸(HIS3报告基因活性和β半乳糖苷酶实验,初步确定与催化TPOR活性域片段相互作用的蛋白,最终通过免疫共沉淀和免疫荧光技术来确认。结果: 分别构建含野生型MIF的pBTM116-MIF和野生型硫氧还蛋白样蛋白2(TXNL2)的pACT2-TXNL2质粒,将其共转染L40酵母菌。HIS3报告基因活性检测和β半乳糖苷酶阳性实验结果提示TXNL2可能是与MIF催化 TPOR活性片段相互作用的蛋白。将重组质粒pcDNA3.1-Myc-TXNL2转染MCF7细胞,免疫共沉淀实验结果表明MIF抗体能够共沉淀Myc-TXNL2蛋白;免疫荧光结果显示Myc-TXNL2与MIF在细胞质中位置分布相同。结论: TXNL2可能是与MIF催化TPOR活性片段相互作用的蛋白。本研究为MIF氧化还原机制的研究提供了新的实验依据。     

类酵母细胞对UF-50尿沉渣分析仪测定结果的影响

目的研究类酵母细胞对UF-50尿沉渣分析仪测定误差，提高尿液检测的准确度。方法将血液、精液和富含类酵母细胞的尿液标本作预处理后，用UF-50尿沉渣分析仪作沉渣分析，同时用牛鲍氏计数板计数，将分析结果加以比较。结果UF-50分析仪测定的类酵母细胞与牛鲍氏法所测的结果有显著性差异（P＜0．05），而以上两种方法检测的红细胞、自细胞和精子数无显著性差异（P＞0．05），实验中发现在UF-50尿分析仪检测中，易将类酵母细胞误计数为红细胞、自细胞和精子。结论在UF-50尿分析仪检测尿液有形成份时，类酵母细胞是引起检测误差的一个重要原因，易导致临床误诊，镜检可以克服这一偏差。     

检测常见酵母菌耐药性的纸片法和微量稀释法比较

目的用纸片法和微量稀释法检测痰液标本分离酵母菌的耐药性并比较两者符合率,试找出一种适用于临床实验室的简便方法。方法采用丹麦ROSCO公司抗真菌药敏纸片法检测痰液标本分离的86株常见酵母菌对5种抗真菌药物的敏感性,同时用法国生物梅里埃公司ATB FUNGUS 2念珠菌药敏板条测定4种抗真菌药物的最小抑菌浓度,对结果进行分析。结果两性霉素B、氟胞嘧啶、氟康唑2种方法完全符合率分别为95.3%、95.3%和88.4%,未出现一种方法敏感而另一种方法耐药的严重错误现象;对86株痰液标本分离常见酵母菌的耐药性进行分析,两性霉素B、制霉菌素和氟胞嘧啶的敏感率高,分别为95.4%、98.8%、95.3%,伊曲康唑的耐药率最高(15.1%)。结论纸片法和微量稀释法相比有很好的一致性,且抗真菌药敏纸片种类多,便于随时根据临床所需增加单个药敏结果,易于在各临床实验室开展。酵母菌唑类抗真菌药物的耐药现象日益严重,应加强酵母菌的耐药性监测。     

临床分离真菌耐药性分析

目的监测分析临床分离真菌对抗菌药物的耐药现状,以加强抗真菌药物的合理应用。方法对我院2007年1月至2007年6月分离鉴定出的479株真菌用目前常用的5种抗真菌药物进行药物敏感性试验和分析。结果479株真菌中念珠菌和其他真菌分别占98.3%和1.7%,其中前3位依次是白念珠菌(69.5%)、光滑念珠菌(16.9%)和热带念珠菌(8.8%)。在5种抗真菌药物中,耐药率由高到低依次为伊曲康唑(12.7%)、氟康唑(9.8%)、伏立康唑(7.5%)、氟胞嘧啶(1.8%)和两性霉素B(1.0%)。结论临床分离的真菌对当前常用抗真菌药物的耐药菌株增多,应引起重视。     

糖尿病并发症相关基因醛糖还原酶酵母细胞模型的建立

目的 构建由绿色荧光蛋白（GFP）标记的糖尿病慢性并发症相关基因醛糖还原酶（AR）表达载体，并在酵母细胞中表达，建立AR抑制剂筛选模型。方法 构建AR与GFP的嵌合基因，将此AR：：GFP嵌合基因克隆到酵母表达载体pYEX-BX中，再将重组载体pYEX-BX-AR：：GFP转化至酵母宿主菌INVSC1，在SC-UD选择性培养基中表达AR：：GFP。结果 PCR扩增出约l106bp大小片段，为AR基因片段；RT-PCR在酵母细胞中检测到ARmRNA的表达；经CuS04诱导后可见AR：：GFP融合蛋白的绿色荧光；诱导剂CuSO4终浓度在100～200μmol／L范围内相对荧光强度较高，细胞密度适中；培养基SC-UD的pH值为6左右最适合细胞生长和荧光表达。结论 AR：：GFP在酿酒酵母中成功地表达，酵母细胞是研究目的基因功能与表达的良好模式菌。     

Cloning and characterization of a novel hepatitis B virus core binding protein C12

AIM: To elucidate the biological function of HBV core antigen (HBcAg) on pathogenesis of hepatitis B, a novel gene C12 coding for protein with unknown function interacting with HBcAg in hepatocytes was identified and characterized. METHODS: HBcAg bait plasmid pGBKT7-HBcAg was constructed and transformed into yeast AH109, then the transformed yeast was mated with yeast Y187 containing liver complementary DNA (cDNA) library plasmid in 2×YPDA medium. Diploid yeast was plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X-α-gal for screening twice. After extracting and sequencing of plasmid from blue colonies, we isolated a cDNA clone encoding a novel protein designated as C12 that directly interacted with HBcAg. The interaction between HBcAg and C12 was verified again by re-mating. PEGFP-N1-C12 fluorescent protein fusion gene was transfected in 293 and L02 cell, and observed by fluorescent microscope. MTT reduction assay was used to study the action of C12 protein effect on metabolism of mammal cell. Yeast two-hybrid and cDNA microarray were performed to search binding protein and differential expression genes regulated by C12 protein. RESULTS: C12 gene was screened and identified by yeast two-hybrid system 3. The interaction between HBcAg and the novel protein coded by the new gene C12 was further confirmed by re-mating. After 48 h, fluorescence of fusion protein could be observed steadily in the 293 and L02 cell plasma. Under MTT assay, we found that the expression of C12 did not influence the growth of liver cells. Seventeen differential expression genes in HepG2 cells transfected with C12 protein expression plasmid by cDNA microarray, of which 16 genes were upregulated and 1 gene was downregulated by C12 protein. Twenty-one colonies containing 16 different genes coding for C12 protein binding proteins were isolated by yeast two-hybrid, there were 2 new genes with unknown function. CONCLUSION: The novel protein C12 is located in cell plasma, and its overexpression has no significant effect on the metabolism of liver cell. It interacts with many proteins in hepatocytes and may be involved in many processes of gene expression.     

人CDK2-AP1(DOC-1)酵母双杂交诱饵质粒自激活作用鉴定

目的验证诱饵质粒pBD—DOC-1在酵母双杂交系统的自激活性及毒性作用，为应用酵母双杂交系统（yeasttwo—hybrid system）筛选与p12DOC-1／CDK2-AP1相互作用的蛋白建立实验基础。方法将诱饵质粒pBD—DOC-1转化到酵母细胞MAV203中，检测诱饵蛋白有无毒性和自激活作用。同时利用对照质粒组筛选组氨酸（His）本底表达抑制剂3AT（3-氨基．1，2，4-三唑）的合适工作浓度。结果诱饵质粒pBD．DOC—1成功转化到酵母细胞MAV203中，对宿主酵母细胞无毒性，对报告基因无自激活作用。确定了组氨酸（His）本底表达抑制剂3AT（3-氨基-1，2，4-三唑）的合适工作浓度。结论诱饵质粒pBD—DOC-1可以用于酵母双杂交实验，为进-步运用酵母双杂交技术在人类组织cDNA文库中筛选与之相互作用的蛋白奠定了基础。