一株牛病毒性腹泻/黏膜病强毒株的分离与鉴定

从云南某牛场疑似BVDV感染的病料通过接种MDBK细胞分离到1株BVDV,将其命名为BVDV/W。该分离毒株连传15代均不产生CPE,为NCP型BVDV。通过电镜检测可观察到直径为 40～60nm病毒粒子。该分离病毒能被牛病毒性腹泻标准阳性血清中和,且能被BVDV IFA荧光抗体识别;针对常用作BVDV基因分型的5′-UTR设计特异性引物,经RT-PCR可扩增出288bp特异性片段。将所测的目的片段序列与中参考序列进行同源性比较,结果显示与293株和Y2株同源关系较近,分别为90.0%和89.9%,与2014年以来我国报道的分离株同源性在88%左右,具有一定的代表性。5′-UTR遗传进化分析证实该分离毒株为BVDV-1型。动物回归试验显示,该分离毒株可引起出现体温升高、腹泻、粘膜病等典型的BVD/MD症状,表明该毒株为1株BVD强毒株。     

淮南地区荷斯坦奶牛泌乳系统性状的线性评定及分析

以安徽淮南乳品公司为试验试点．随机抽取荷斯坦奶牛493头(1～11胎)，进行奶牛体型线性评定中泌乳系统性状即前房附着、后房高度、后房宽度、悬韧带、乳房深度、乳头位置和乳头长度的线性选择评定及分析。结果表明：淮南地区荷斯坦奶牛泌乳系统性状的表现中等偏好．前房附着、后房高度、后房宽度、悬韧带、乳房深度、乳头位置、乳头长度的线性评分分别是31．95、46．98、29，09、37．47、15．08、39．74和20．82分．评定等级各为佳、优、好、良、中、良、中。同时，后房高度、后房宽度、乳头位置的线性评分随胎次变化而变化很小且无规律可循，各胎次几乎相同；乳头长度、悬韧带的线性评分随胎次升高而增加，但后者幅度很小；前房附着、乳房深度的线性评分均表现随胎次的升高而降低的趋势。     

Genetic characterization of a novel bovine papillomavirus member of the Deltapapillomavirus genus

This report describes the complete genomic sequence and taxonomic position of BPV type 13. The BPV13 genome was amplified using the multiply primed rolling-circle amplification technique and long-template PCR employing two specific primers. The two long PCR fragments obtained were cloned and sequenced via primer walking. The complete genomic sequence of the BPV13 contains 7961 bp encoding eight proteins, E1, E2, E4, E5, E6, E7, L1, and L2. Similarly to the E5 gene in BPVs 1 and 2, the putative BPV13 E5 ORF encodes a small transforming protein that contains a hydrophobic transmembrane domain. Meanwhile, the retinoblastoma tumor suppressor-binding domain is absent in the putative BPV13 E7 protein. The presence of these two specific molecular features has been recognized as a distinct marker for the development of fibropapilloma in artiodactyl PV-induced lesions. The phylogenetic analysis demonstrated that BPV13 is a new member of the Deltapapillomavirus genus, to be classified as the third representative of the Delta 4 species. The characterization of the genomic sequence of this novel PV will aid in the interpretation of the pathologies described to be related to this virus and provide support for the development of diagnostic tools for epidemiological surveillance of BPV13 in its potential natural hosts.     

河源某猪场两种猪瘟疫苗田间免疫效果对比试验

通过在河源某猪场,对不同厂家两种猪瘟疫苗单独使用及混合使用后的的免疫效果对比,得出以下结论：首免和二免均使用猪瘟传代细胞苗免疫的效果最好;首免使用猪瘟脾淋苗,二免使用猪瘟传代细胞苗免疫的效果次之;首免和二免均使用脾淋苗免疫的效果最差。     

杜仲素对奶牛生产性能和免疫机能的影响

本试验旨在研究日粮中添加杜仲素对奶牛生产性能及血液免疫指标、抗氧化指标的影响。选择40头胎次和产奶量相近的中国荷斯坦牛并随机分为两组进行试验,试验组奶牛在对照组日粮基础上每日灌服20g杜仲素,研究其对奶牛生产性能的影响,试验期为75d。另外,选择8头患有乳房炎的奶牛,每日灌服50g杜仲素,观察其对奶牛血液免疫指标和抗氧化指标的影响,试验期为30d。结果表明,1)杜仲素的添加对奶牛采食量无明显影响,能明显提高受胎率,预防乳房炎的发生;2)杜仲素显著降低了牛奶体细胞数(P<0.05);3)杜仲素对产奶量基本没有影响,对乳脂率有提高作用,但显著降低了乳蛋白率(P<0.05);4)杜仲素显著降低了奶牛血液中丙二醛(MDA)水平,有提高血液中IgG含量的趋势,对血液中谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、IgM、IgA没有显著影响。由此可见,日粮中添加杜仲素能在一定程度上提高机体的免疫力和抗氧化能力,预防乳房炎的发生,提高繁殖性能。     

Staphylococcus aureus and Escherichia coli elicit different innate immune responses from bovine mammary epithelial cells

Escherichia coli and Staphylococcus aureus are the most important pathogenic bacteria causing bovine clinical mastitis and subclinical mastitis, respectively. However, little is known about the molecular mechanisms underlying the different host response patterns caused by these bacteria. The aim of this study was to characterize the different innate immune responses of bovine mammary epithelium cells (MECs) to heat-inactivated E. coli and S. aureus. Gene expression of Toll-like receptor 2 (TLR2) and TLR4 was compared. The activation of nuclear factor kappa B (NF-κB) and the kinetics and levels of cytokine production were analyzed. The results show that the mRNA for TLR2 and TLR4 was up-regulated when the bovine MECs were stimulated with heat-inactivated E. coli, while only TLR2 mRNA was up-regulated when the bovine MECs were stimulated with heat-inactivated S. aureus. The expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and IL-8 increased more rapidly and higher when the bovine MECs were stimulated with heat-inactivated E. coli than when they were stimulated with heat-inactivated S. aureus. E. coli strongly activated NF-κB in the bovine MECs, while S. aureus failed to activate NF-κB. Heat-inactivated S. aureus could induce NF-κB activation when bovine MECs cultured in medium without fetal calf serum. These results were confirmed using TLR2- and TLR4/MD2-transfected HEK293 cells and suggested that differential TLR recognition and the lack of NF-κB activation account for the impaired immune response elicited by heat-inactivated S. aureus.     

牛疱疹病毒1型主要囊膜糖蛋白研究进展

牛疱疹病毒(BHV-1)属于α疱疹病毒亚科的DNA病毒,可引起牛高热、上呼吸道感染和母牛流产。该病毒能在牛的感觉神经节内建立潜伏感染,因此,对于该病毒感染的预防和治疗较为困难。BHV-1除了引起初始感染外,还可通过免疫抑制引起动物继发感染,导致动物死亡。研究发现,病毒入侵牛机体时,病毒囊膜糖蛋白在病毒与细胞间相互作用的过程中发挥了重要作用。论文对牛疱疹病毒1型主要囊膜糖蛋白(包括gB、gD、gN)的结构特征和生物学特征加以归纳总结,为该病毒的感染特性研究和预防提供参考。     

牛精液中基因I型牛病毒性腹泻病毒荧光探针定量RT-PCR检测方法的建立

为建立牛精液中基因I型牛病毒性腹泻病毒(BVDV-1)的快速检测方法,本研究采用Sephycral S-400凝胶对牛精液过滤处理后提取病毒核酸,根据BVDV-1 5'UTR保守区基因序列,设计特异性引物和荧光探针,通过反应条件的优化,建立了牛精液中BVDV-1荧光定量RT-PCR检测方法.该方法可以检测到牛精液中含量为0.0125 TCID50的病毒,灵敏度比病毒分离方法高200倍～2000倍,比常规RT-PCR方法高10倍.对从同一个牛场6个月内采集的120份新鲜牛精液和40份冷冻牛精液用该荧光RT-PCR方法检测,没有检测到BVDV-1阳性样品.对其中的10头牛定期检测精液中病毒的同时,并同步检测了全血中的病毒和血清抗体,结果血清抗体阳性牛精液中没有检测到病毒,本研究结果表明,不能以血清抗体阴阳性做为精液是否带毒的依据.