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为快速检测出食用肉类中掺假物质,确保消费者切身利益,维持正常市场秩序,提升贵州省产品质量监督检验的检测能力,采用实时荧光定量PCR对猪源性成分和牛源性成分进行检测.结果表明:荧光PCR可以用来检测猪、牛等动物源性成分,且检测灵敏度为1％;荧光PCR检测动物源性成分提高了检测效率及灵敏度,降低了假阳性机率.     

Cattle‐associated risk factors for human tuberculosis in rural livestock‐keeping communities,Uganda

Tuberculosis (TB) is a leading infectious cause of human death worldwide. In cattle, TB infection results in productivity losses, trade barriers and zoonotic transmission via milk, meat or direct contact. We conducted a cross‐sectional study in rural communities in Uganda between 2014 and 2016 to evaluate the association between tuberculosis skin test (TST) positivity in humans and cattle‐associated risk factors: household herd positivity and raw milk consumption. Human and cattle TSTs were performed in communities followed by a survey of household practices. TST data were available on 493 humans, 184 (37.3%) with positive results, and 1,441 cattle, 50 (3.5%) with positive results. We fit separate log binomial generalized estimating equation models for the herd positivity‐human TST positivity association, stratified on sex; and for the raw milk consumption‐human TST positivity association, stratified on frequency of milk consumption. Having at least one TST‐positive bovid in the household's herd was significantly associated with lower risk of TB among men (prevalence ratio [PR] 0.66, 95% CI 0.49, 0.87) but was not significantly associated with TB among women (PR 1.21, 95% CI 0.76, 1.95). This apparent protective effect was contrary to our a priori hypothesis of higher exposure effect among men, the primary caretakers of cattle. This finding may be the result of residual confounding by socioeconomic status; wealthier individuals may be less likely to be TB positive, but more likely to have TST‐positive herds by virtue of larger herd sizes, ability to purchase new and possibly infected stock, and propensity to keep more TB‐susceptible European breeds. For raw milk consumption, effect estimates were close to one and not statistically significant. Thus, in settings where bovine TB prevalence is low, such as Uganda, cattle‐associated zoonotic transmission may be rare, and cattle‐associated risk factors may not be important drivers of human TB burden.     

促性腺激素对猪卵母细胞体外成熟的影响

在成熟液中同时添加不同浓度(0.25～2.0μg/mL)FSH和不同浓度(0.25～2.0μg/mL)LH,探讨这2种促性腺激素结合使用对猪卵母细胞体外成熟的影响。结果显示,当FSH的添加浓度为0.25～2.0μg/mL及LH的添加浓度为0.25～2.0μg/mL时,猪卵母细胞的核成熟率极显著高于没有添加FSH和LH的对照组(P<0.01),而FSH和LH不同浓度组合之间对猪卵母细胞核成熟影响差异不显著(P>0.05)。结果表明,成熟液中同时添加0.25μg/mLFSH和0.25μg/mLLH便能极显著地促进猪卵母细胞的核成熟率,国产FSH和LH用于猪卵母细胞体外成熟研究是可行的。     

两种方法对牛体外受精及体外发育的影响

本研究包括２个试验。试验１，采用由多种大分子物质组成的生物试剂Ｐｅｒｃｏｌ做成离心梯度，离心处理精液获得较高活率的精子。将其用于卵母细胞的体外受精，在使用４５μＬ大小的受精滴及２×１０６个／ｍＬ的最终受精精子浓度时，加入２０个或４０个卵母细胞，二者均获得较高的分裂率（％）８９．０±５．０、８８．１±３．８及囊胚率（％）５１．０±７．０、４６．３±１６．７。试验２，为了更接近胚胎在母牛体内发育的实际状态（动态），采用一种新的方法即将摇床振动培养引入牛早期胚胎的体外发育阶段，以期提高胚胎发育质量。结果表明，在早期胚胎基数及环境因素完全一致的前提下，振动培养组的囊胚发育率（％）及囊胚卵化率（％）分别为６１．１±１２．２、８２．６±６．８，而常规的静置培养组为６７．４±６．３、８８．０±７．４，方差计算表明二者无显著差异（Ｐ＞０．０５）。     

液相色谱-电喷雾串联四极杆质谱法同时测定牛肉中地塞米松、倍他米松和倍氯米松残留

【研究目的】建立一种可检测实际牛肉样品中地塞米松、倍他米松和倍氯米松药物残留的液相色谱-电喷雾串联四极杆质谱方法;【方法】样品在碱性条件下经乙酸乙酯提取,正已烷脱脂,通过MCX固相萃取小柱净化后,进行液相色谱-质谱分析。采用Xterra MS C18色谱柱,以均含1％甲酸的乙腈和水为流动相做梯度洗脱;【结果】方法的检出限和定量限为0．5μg／kg和2．0μg/kg,三种药物添加水平为0．5、2和50μg／kg时。方法的回收率在77．6％～97．9％之间,批内变异系数为2．5％～7．9％,批间变异系数为3．10%～8．7％;【结论】所建方法简便快速,可用于实际应用。     

牛IL-2 cDNA缺失突变的矫正及表达产物生物学活性测定

根据GenBank中的牛IL-2基因序列，设计一对引物Pa和Pd，以牛外周血淋巴细胞为材料，用RT-PCR方法扩增得到牛IL-2 cDNA，测序发现在扩增产物的第240位缺失了一个A碱基。采用重叠延伸剪接术(SOE法)向突变体定点插入该碱基，然后与表达载体连接，获得了正确的表达产物。经RT-PCR检测证明，重组的牛IL-2蛋白具有较好的生物学活性，能诱导肿瘤坏死因子TNF-α和干扰素IFN-γ的产生。     

牛流行热病毒感染白纹伊蚊细胞免疫调控相关基因的差异表达分析

为了阐明牛流行热病毒(bovine ephemeral fever virus,BEFV)在媒介蚊形成持续感染过程中免疫相关基因的调控作用,利用白纹伊蚊幼蚊细胞C6/36从牛体传代抗凝血分离BEFV JT02L株,用geNorm和NormFinder软件分析感染细胞看家基因的mRNA表达水平稳定性,筛选获得最稳定表达的...     

Cloning and Prokaryotic Expression of L1 Gene of Bovine Papillomavirus Genotype 13

This experiment was conducted to clone and express L1 gene of bovine papillomavirus genotype 13 (BPV13).Specific primers were designed according to the published sequences of BPV13, and 1 494 bp L1 gene fragment was amplified by PCR.After digestion by BamHⅠand Hind Ⅲ, the fragment was inserted into the prokaryotic expression vector pET28a(+) to construct the recombinant plasmid pET28a-L1.The recombinant plasmid pET28a-L1 was identified by double enzyme digestion and nucleotide sequencing, and was transformed into E.coli BL21(DE3).The expression of pET28a-L1 was induced by IPTG after selecting the best concentration and time.The results showed that L1 gene was exactly inserted into the prokaryotic expression vector pET28a(+), after induction, the target protein containing His-tag was successfully expressed by expression bacteria which included recombinant plasmid pET28a-L1;SDS-PAGE result showed that the molecular mass of the protein was 60 ku which was consistent with the expected size;After ultrasonic treatment, SDS-PAGE result showed that the protein existed in the precipitation;The target protein was a fusion protein with His-tag verified by Western blotting.This study laid a solid foundation for the research of function of BPV13 L1 gene and the development of effective DNA vaccine of BPV13.     

山羊卵子发育、受精和老化过程的电镜组化研究

应用改良柠檬酸铅法、Tris-Malcate法和Dermer氏保存磷脂的固定方法,分别研究了山羊卵母细胞发育、受精和老化过程中硷性磷酸酶(Alpase)、酸性磷酸酶(Acpase)和磷脂的超微结构定位和含量。结果表明,a.碱性磷酸酶主要定位于MV.卵皮质和伸入到卵母细胞内的颗粒细胞突起上;生长卵母细胞的硷性酸酶活性很强,排卵后活性减弱,受精卵中无Alpase活性。b.排卵24小时后卵母细胞内开始出现Acpase阳性的髓样小体,并随卵老化而逐渐增多。c.卵母细胞脂滴内磷脂含量很少,且恒定;MV、ZP、质膜和Mi上都含有许多磷脂;生长卵母细胞MV和质膜上磷脂多,排卵后减少;受精卵质膜和Mi膜上磷脂明显增多。文中讨论了酶和磷脂变化与卵母细胞生理状态的关系。     

基于小鼠粪便气味信息的牛乳清蛋白功能效果的鉴别区分

以电子鼻气敏传感器阵列跟踪牛乳清蛋白干预小鼠粪便气味,以期建立基于气味信息无损评价牛乳清蛋白功能的新方法.动物实验结果表明,与NS组比较,给药牛乳清蛋白试验组血清中的超氧化物歧化酶(SOD)活性上升,丙二醛(MDA)含量显著下降,牛乳清蛋白在小鼠血清中具有抗氧化的能力.电子鼻实验单因素方差分析发现,样品量、顶空生成时间...