北疆部分地区食源性大肠杆菌血清型、毒力基因及耐药基因的研究

目的研究北疆部分地区食源性大肠杆菌的优势血清型、毒力基因和耐药基因的相关性。方法采用玻片凝集法测定了大肠杆菌血清型分布,PCR方法调查11种耐药基因和9种毒力基因。结果血清试验,定型菌株26株,分别属于17种血清型,其中O1、O115为优势血清型;PCR结果表明,不含有所检测耐药基因的分离株占12.50%,至少含有2种以及以上的分离株占50.00%,分离株对blaOXA基因携带率高达57.14%;检出率较高的毒力基因为fimC(64.29%)和fimA(25.00%)。结论 O1、O115为主要的血清型,2种血清型菌株拥有的耐药基因谱和毒力基因谱不相同。     

The telomere-associated MAL3 locus of Saccharomyces is a tandem array of repeated genes.

Saccharomyces strains capable of fermenting maltose contain any one of five telomere-associated MAL loci. Each MAL locus is a complex of three genes encoding the three functions required to ferment maltose: maltose permease (GENE 1), maltase (GENE 2) and the MAL trans-activator (GENE 3). All five loci have been cloned and all are highly sequence homologous over at least a 9.0 kbp region containing these GENEs (Charron et al., Genetics 122, 307-331, 1989). Our initial studies of strains carrying the MAL3 locus indicated the presence of linked, repeated MAL-homologous sequences (Michels and Needleman, Mol. Gen. Genet. 191, 225-230, 1983). Here we report our analysis of the centromere-proximal MAL3-linked sequences and show that the complete MAL3 locus spans approximately 40 kbp and consists of tandemly arrayed, partial repeats of the three GENE sequences described above. In addition, the structure of the MAL3 locus is compared to that of three partially functional alleles of MAL3. These alleles were shown to contain only MAL31 and MAL32 and their structure suggests that they resulted from MAL3 deletions removing the sequences centromere-proximal to MAL31. The amplification and rearrangement of the telomere-linked MAL3 sequences are discussed in the context of studies on other telemere-associated sequences from yeast and other species.     

单核细胞增生李斯特菌菌株分型与其致病潜力基因相关性研究进展

单核细胞增生李斯特菌是一种常见的食源性致病菌,该菌分型繁多。不同分型的单核细胞增生李斯特菌致病潜力不同,这与菌株所携带的抗性基因和毒力基因不同有关。本文综述了不同分型单核细胞增生李斯特菌与抗性基因和毒力基因的关系,结果发现与该菌抗性相关的基因,如热抗性、耐冷性、酸抗性、耐高渗、耐干燥、耐金属和杀菌剂及参与应激蛋白表达调控的基因较多,它们与分型之间的关系暂无明确相关性结论,但也发现应激生存岛（stress survival island,SSI）-1仅存在于谱系I和谱系II部分菌株中,SSI-2目前仅被发现在ST121菌株中携带。从功能毒力基因和李斯特菌毒力基因岛（Listeria pathogenicity islands,LIPI）两方面分述了毒力基因,LIPI-3和LIPI-4主要存在于谱系I菌株中。此外,ST5、ST8、ST9和ST121菌株的inlA基因中出现提前终止密码子,使得菌株的毒力降低。研究不同分型单核细胞增生李斯特菌致病潜力基因的差异有助于单核细胞增生李斯特菌的预警预测、防控,并为不同分型菌株致病机制的深入研究提供参考。     

基于单拷贝核基因的数字PCR定量检测肉制品中羊源性成分

GeneBank搜索牛、绵羊、山羊、猪、马、驴、鸡、鸭、鹅、火鸡、狗、猫、鼠、兔、貂等15种动物的单拷贝核基因组序列信息,应用生物信息学分析筛选15种动物共有的种间保守区域,设计一对可同时扩增15种动物源性DNA的内参基因引物和探针;同时分析筛选绵羊和山羊共有且和其余动物种内特异性区域,设计一对只能扩增羊源性DNA的特异性基因引物和探针。基于微滴数字PCR技术,引入内参基因校正羊种属特异性基因测定方法,建立科学准确的肉制品中羊源性成分量化判定方法。结果表明,所建立方法具有良好的特异性和通用性,内参基因和羊种属特异性基因的最低检出限分别为32和26 copies/μL,模拟添加样品的正确度偏差均值为8.66%,符合数字PCR方法制定指南要求不得大于25%,说明量化判定方法结果具有较高的准确性。     

婴幼儿食品中金黄色葡萄球菌污染情况及其耐药基因和新型肠毒素基因的检测

本文调查了婴幼儿奶粉和米粉中金黄色葡萄球菌的污染状况,并且检测其耐药基因和新型肠毒素基因。采集陕西省2010年和2012年间不同品牌的婴幼儿奶粉和米粉692份,进行金黄色葡萄球菌污染检验,采用PCR对分离菌株进行31种耐药基因和9种新型肠毒素基因的检测。692份样品中金黄色葡萄球菌的检出率为7.80%,其中2010年所采样品的检出率为8.17%,2012年所采样品的检出率为7.38%。分离的75株菌最终检测出12种耐药基因和2种新型肠毒素基因,检出率最高的耐药基因是tet K(72.00%),其次是bla Z(36.00%),erm C(29.33%),tet(K)F(21.33%),lin A/lin A’(12.00%),dfr G(8.00%),tet L(6.67%)和acc(6')(5.33%),最少的为erm B,msr A、msr B和drf K(均为1.33%)。新型肠毒素基因仅检测出sen(44.00%)和ser(4.00%)。不同采样年份、生产季节和货架期的样品中金黄色葡萄球菌的污染率不存在显著差异。并且这些菌株主要携带四环素、青霉素和大环内酯类抗生素的耐药基因,以及新型毒素基因sen。     

苏州市食品中单增李斯特菌污染状况及分子特征分析

目的 研究2016-2020年苏州市各类食品中单增李斯特菌的污染状况及分子特征.方法 将采样食品按WS/T 464-2015《食物成分数据表达规范》进行分类,计算各类食品污染率,通过聚合酶链式反应(polymerase chain reaction,PCR)和凝胶电泳对毒力基因(inlA、inlB)和耐药相关基因(vi...     

利用菌株的乳链菌肽免疫性筛选高产菌株

根据乳链菌肽产生菌的基因分析 ,发展了一种新的筛选方法。对乳酸乳球菌 79UV-S2 2经多种诱变处理后 ,用该方法进行了筛选 ,成功地获得了一株乳链菌肽高产菌株 ,该菌株在遗传上是稳定的 ,使用M 1 7培养基发酵发酵液效价可达 1 5 2 7IU/mL。     

Structural characterization of chromosome I size variants from a natural yeast strain

Many yeast strains isolated from the wild show karyotype instability during vegetative growth, with rearrangement rates of up to 10(-2) chromosomal changes per generation. Physical isolation and analysis of several chromosome I size variants of one of these strains revealed that they differed only in their subtelomeric regions, leaving the central 150 Kb unaltered. Fine mapping of these subtelomeric variable regions revealed gross alterations of two very similar loci, FLO1 and FLO9. These loci are located on the right and left arms, respectively, of chromosome I and encompass internal repetitive DNA sequences. Furthermore, some chromosome I variants lacking the FLO1 locus showed evidence of recombination at a DNA region on their right arm that is enriched in repeated sequences, including Ty LTRs. We propose that repetitive sequences in many subtelomeric regions in S. cerevisiae play a key role in karyotype hypervariability. As these regions encode several membrane-associated proteins, subtelomeric plasticity may allow rapid adaptive changes of the yeast strain to specific substrates. This pattern of semi-conservative chromosomal rearrangement may have profound implications, both in terms of evolution of wild strains and for biotechnological processes.     

Association of single nucleotide polymorphisms in candidate genes previously related to genetic variation in fertility with phenotypic measurements of reproductive function in Holstein cows

Many genetic markers related to health or production traits are not evaluated in populations independent of the discovery population or related to phenotype. Here we evaluated 68 single nucleotide polymorphisms (SNP) in candidate genes previously associated with genetic merit for fertility and production traits for association with phenotypic measurements of fertility in a population of Holstein cows that was selected based on predicted transmitting ability (PTA) for daughter pregnancy rate (DPR; high, ≥1, n = 989; low, ≤ ?1.0, n = 1,285). Cows with a high PTA for DPR had higher pregnancy rate at first service, fewer services per conception, and fewer days open than cows with a low PTA for DPR. Of the 68 SNP, 11 were associated with pregnancy rate at first service, 16 with services per conception, and 19 with days open. Single nucleotide polymorphisms in 12 genes (BDH2, BSP3, CAST, CD2, CD14, FUT1, FYB, GCNT3, HSD17B7, IBSP, OCLN, and PCCB) had significant associations with 2 fertility traits, and SNP in 4 genes (CSPP1, FCER1G, PMM2, and TBC1D24) had significant associations with each of the 3 traits. Results from this experiment were compared with results from 2 earlier studies in which the SNP were associated with genetic estimates of fertility. One study involved the same animals as used here, and the other study was of an independent population of bulls. A total of 13 SNP associated with 1 or more phenotypic estimates of fertility were directionally associated with genetic estimates of fertility in the same cow population. Moreover, 14 SNP associated with reproductive phenotype were directionally associated with genetic estimates of fertility in the bull population. Nine SNP (located in BCAS, BSP3, CAST, FUT1, HSD17B7, OCLN, PCCB, PMM2, and TBC1D24) had a directional association with fertility in all 3 studies. Examination of the function of the genes with SNP associated with reproduction in more than one study indicates the importance of steroid hormones and immune function as determinants of reproductive function. All but 1 of the 68 evaluated SNP were variable in 11 breeds besides Holstein, indicating the potential effects of these SNP on reproductive function across breeds of cattle.     

转抗菌肽基因辣椒食用安全性和营养质量评价

依据中华人民共和国卫生部《转基因食品卫生管理办法》的有关规定，对转抗菌肽基因辣椒食用安全性和营养质量进行评价，探讨建立相关的模式和方法，为我国转基因食的卫生管理提供可资借鉴的模型和方法，以转抗菌肽基因辣椒及其对应的受体辣椒为材料，通过对其外源基因及其表达产物，主要营养成分的检测，鉴定转基因食品的特性，基因重组体的遗传稳定性，外源基因的表达忠实性，与受体辣椒的实质等同性，分析和评价其食用安全性和营养质量，抗菌肽基因辣椒其受体，外源基因供体均为传统食品，其基因重组体的主要特性的遗传是稳定的，其外源目的基因的表达是忠实的，其食安全性和营养质量不低于对应的原有食品。     

Physical map locations of the phospholipid biosynthetic structural and regulatory genes of Saccharomyces cerevisiae

Here we report the physical map locations of five genes required for phospholipid biosynthesis in Saccharomyces cerevisiae. These include four structural genes (INO1, CHO2, OP13 and PIS1) and one global negative regulatory gene (UME6). Collectively, this information completes the mapping of all phospholipid biosynthetic structural and regulatory genes identified to date.     

乳糜泻研究进展

乳糜泻是一种遗传易感个体因摄入含麸质蛋白的谷物(小麦、大麦和祼麦)及其制品而诱发的慢性自身免疫性肠病,影响着世界上约1%人口的健康,并呈增长趋势;在中国可能也存在乳糜泻"冰山"现象,发生率远比原先预计的高;然而目前,中国从事医疗卫生和食品工业的专业人员对乳糜泻的认识仍存在不足。本文着重介绍了国内外在乳糜泻的流行病学、发病机制、临床症状、诊断和治疗等方面的研究进展。全面了解乳糜泻的相关知识,提高对乳糜泻的意识,有助于推动中国对乳糜泻的预防和控制,促进无麸质食品的开发和研究。     

The list of cytoplasmic ribosomal proteins of Saccharomyces cerevisiae

Screening of the complete genome sequence from the yeast Saccharomyces cerevisiae has enabled us to compile a complete list of the genes encoding cytoplasmic ribosomal proteins in this organism. Putative ribosomal protein genes were selected primarily on the basis of the sequence similarity of their products with ribosomal proteins from other eukaryotic organisms, in particular the rat. These genes were subsequently screened for typical yeast rp-gene characteristics, viz. (1) a high codon adaptation index; (2) their promoter structure and (3) their responses to changes in growth conditions. The yeast genome appears to carry 78 different genes, of which 59 are duplicated, encoding 32 different small-subunit and 46 large-subunit proteins. A new nomenclature for these ribosomal proteins is proposed. © 1998 John Wiley & Sons, Ltd.     

1株耐热蜡样芽孢杆菌的鉴定及其缓解炎症性肠病的功效评价

目的：使用多种鉴定方法联合鉴定1株实验室未知菌株，并利用葡聚糖硫酸钠诱导的实验性小鼠结肠炎模型，评价其缓解炎症性肠病的功效。方法：利用16S rRNA和保守蛋白编码基因gyrA及gyrB进行初步鉴定，通过毒力基因nheA、nheB、nheC、hblA、hblC、hblD、becT、cytK、entFM及其生化反应特性确定种属，并测定分离菌在不同温度、pH值以及人工胃肠液的耐受特性。进一步建立实验性结肠炎小鼠模型，探究其缓解炎症性肠病的潜在功效。结果：分子及生理生化鉴定结果显示分离菌为蜡样芽孢杆菌（Bacillus cereus），并命名为HMPM18123。生长特性测定结果还显示，该菌株具有良好的耐高温和胃液肠液耐受特性。此外，该菌株具有改善实验性小鼠结肠炎的功效，具体表现为缓解小鼠结肠炎导致的体质量减低、结肠缩短、疾病活动指数评分升高、组织病变和炎症因子的表达水平上调。