中药复方制剂抗猪传染性胃肠炎病毒活性的研究

通过体外细胞培养试验，采用3种作用方式：先加药物后加病毒、药物和病毒先作用一段时间后加入、先加病毒后加药物，较系统地研究了抗猪传染性胃肠炎病毒有效单味中草药板蓝根、鱼腥草和败酱草所组成的复方制剂对细胞毒性强度及对猪传染性胃肠炎病毒抗吸附、直接灭活和抑制复制作用机理，筛选出同时具有3种方式抗病毒的有效复方制剂，为筛选抗病毒的有效中草药制剂提供新方法。     

猪传染性胃肠炎病毒分子生物学研究进展

本文对猪传染性胃肠炎病毒有关分子生物学方面的最新研究资料进行了概述。ＴＧＥＶ基因组约２９大小,其５‘端是基因１,余下３’端约８．３ｋｂ有６人基因,共有７个亚基因组ｍＲＮＡ,其转录,翻译过程受到病毒的自身的严格调控。基因１编码病毒的主要功能蛋白－聚合酶类有木瓜蛋白酶,类３Ｃ蛋白酶,类生长因子／受体区,聚合酶,金属离子结合区和解旋酶等功能活性区,它们对该酶活性进行调控。     

猪传染性胃肠炎病毒的血凝作用

将猪传染性胃肠炎病毒Ａ株在ＩＢＲＳ２细胞上增殖，增减物经差速离心浓缩后与鸡红细胞出现了高凝集价。这种凝集作用能被兔抗ＴＧＥＶ高免血清所抑制。试验的最适反反应体积分数０．５０％红细胞４℃作用１ｈ。通过反复建立了一种简单实用的血凝抗原制备方法，病毒增减液不需浓缩可直接应用。     

猪传染性胃肠炎病毒分子生物学研究进展

猪传染性胃肠炎病毒(TGEV)基因组为不分段的单股正链RNA,其编码4种结构蛋白和3种非结构蛋白。TGEV S蛋白是基因工程研究的重点,近年来,S蛋白在大肠埃希菌、沙门菌、腺病毒等中得到了高效表达。将传染性胃肠炎病毒的基因组人工改造成为感染性cDNA的表达载体,此载体可在ORF3处插入外源基因,异源基因绿荧光蛋白可稳定、高效地表达。TGEV基因1和其他冠状病毒相比保守性很强,所以对TGEV聚合酶的研究,特别是其中保守酶的研究,对于抗TGEV及其他冠状病毒药物的研究有着重要的意义。     

猪传染性胃肠炎的防制

猪传染性胃肠炎(TGE)是一种高度接触性传染的病毒性传染病,以引起2周龄以下仔猪呕吐、严重腹泻和高死亡率为特征。虽然不同年龄段的猪对这种病毒均敏感,但5周龄以上的猪死亡率很低。育成猪和育肥猪的临床症状轻微,只表现为数天厌食或腹泻。一般情况下,7天即可耐过。     

猪传染性胃肠炎病毒基因工程研究进展

猪传染性胃肠炎病毒(TGEV)是猪的一种重要的传染病病毒，给养猪业造成巨大经济损失。近几年来，随着分子生物学技术的广泛应用．在TGEV的各个方面的研究都取得了长足进展．积累了丰富的资料。本文就来对TGEV的基因工程研究进展作一介绍。     

Sows infected in pregnancy with porcine respiratory coronavirus show no evidence of protecting their sucking piglets against transmissible gastroenteritis

Eighteen litters of sucking piglets were challenged with one of two strains of transmissible gastroenteritis virus (TGEV). During pregnancy, their seronegative dams had been either inoculated intranasally with porcine respiratory coronavirus (PRCV), inoculated orally with TGEV or left untreated. On the basis of weight gain, clinical signs and survival, no differences in response to challenge was detected when piglets suckled by PRCV inoculated sows were compared with those suckled by uninoculated sows. Such a difference was evident when the litters of sows successfully pre-immunized with TGEV were compared with those of unicoculated or PRCV-inoculated sows. The possibility of transplacental transmission of PRCV was investigated in two litters born to sows that had been inoculated with this virus in late pregnancy. All sixteen live-born piglets were seronegative for the virus at birth and PRCV was not isolated from tissues taken from two stillborn piglets.     

猪传染性胃肠炎病毒RT-PCR检测方法的建立和应用

根据GenBank上发表的猪传染性胃肠炎病毒(TGEV)基因序列,针对TGEVN基因全序列设计合成了一对引物,以TGEV疫苗株为模板,建立了检测TGEV的RT-PCR方法。应用该方法对TGEV疫苗株RNA进行扩增,获得与预期大小相符,长度为1168bp的特异性目的片段;测序结果与已报道的TGEV不同毒株的序列同源性达到95%～97%;敏感性测定该RT-PCR可扩增到18pg的TGEV-N-cDNA;对猪传染性胃肠炎(TGE)的病料进行RT-PCR鉴定,可检测出TGEVN基因片段。结果表明建立的RT-PCR方法对TGEV的检测敏感性高、特异性强,可用于TGEV感染的诊断和流行病学调查。     

Intestinal permeability to polyethylene glycol 4000 and porcine albumin in piglets infected with transmissible gastroenteritis virus

The intestinal permeability of specific pathogen free piglets has been studied by measuring the concentration of ¹⁴C in the blood after oral administration of ¹⁴C polyethylene glycol (¹⁴C PEG, MW=4000) and the concentration of ¹³¹I in the faeces after intraperitoneal administration of ¹³¹I porcine albumin (¹³¹I PA, MW=68 000). The tests were performed one day before and up to two days after the piglets were infected with transmissible gastroenteritis (TGE) virus.Jejunal biopsies were taken from two piglets before the experimental infection, from two piglets 12 h after the experimental infection and from five piglets at the end of the experiment, 46 h after infection. Blood samples were taken six-hourly and faecal samples several times.Some piglets vomited before diarrhoea and loss of appetite started at 14 h after infection; the packed cell volume decreased before but increased after infection. Morphological examination showed hyperregenerative villous atrophy at 46 h after infection.There was no increase in the permeation of ¹⁴C PEG but there was a significant increase in the flux of ¹³¹I PA from the blood to the gut lumen.     

检测猪传染性胃肠炎病毒Taq Man荧光定量RT-PCR方法的建立与初步应用

据GenBank登录的猪传染性胃肠炎病毒(TGEV)N基因的保守区序列设计合成了引物和探针,对荧光定量RT-PCR的反应条件进行了优化,建立了一种特异、灵敏、快速的TaqMan荧光定量RT-PCR方法来检测TGEV。与国外进口的An imal Genetics公司生产TGEV抗原快速检测试剂盒进行比较,符合率达到100%;与常规RT-PCR检测方法相比,灵敏度高100倍。用该方法对辽宁、山东、福建等地的送检疑似病料进行了检测,结果阳性率为24%。试验证明,所建立方法适用于猪传染性胃肠炎病毒的分子诊断、流行病学调查等相关研究。     

中草药防治猪传染性胃肠炎的研究进展

猪传染性胃肠炎是由猪传染性胃肠炎病毒引起的一种高度接触性肠道疾病。该病不仅可导致不同品种和各生长期的猪产生呕吐、腹泻和失水等临床症状,还具有传染性强、传播速度快的特点。因此,为了使猪传染性胃肠炎病得到有效的防治,文章主要从猪传染性胃肠炎的危害概况、中草药在猪传染性胃肠炎防治中的应用概况、中药防治猪传染性胃肠炎作用机理3个方面探讨了当前中草药防治猪传染性胃肠炎的研究进展,以期为兽医临床防治猪传染性胃肠炎提供理论依据。     

猪传染性胃肠炎病毒TH-98株S基因的克隆与同源性比较

用猪睾丸 (Swine testicle,ST)细胞繁殖并扩增猪传染性胃肠炎病毒国内分离株 TH- 98,根据 Gen Bank中已发表的TGEV S基因 c DNA序列 ,利用 Oligo4.1程序软件设计并合成两对引物 ,进行逆转录聚合酶链式反应 (RT- PCR) ,扩增出2 .3kb和 2 .1kb两个片段 ,分别命名为 Sa与 Sb,先后插入到 p UC18质粒载体上的 Eco RI和 Pst I多克隆位点上 ,构建了重组质粒 p UC- S。根据 TGEV S基因位点和 p UC18的物理图谱 ,用相应的限制性内切酶进行酶切及套式 PCR方法进行鉴定、分析 ,证明克隆的 p UC- S为 TGEV S基因。同时对 p U C- S进行序列测定分析 ,并与来自美国、英国和日本的五个毒株进行核苷酸及编码氨基酸同源性比较 ,证明了 S基因的高度保守性     

猪传染性胃肠炎病毒TH-98株S基因5′端部分片段克隆及序列分析

本研究扩增出猪传染性胃肠炎病毒 (TGEV) TH- 98株 S基因 5′端 6 72 bp片段 (TS1) ,包括 B、C两个主要抗原位点。将该片段克隆到 p MD 18- T载体上 ,经鉴定 TS1片段正确插入 p MD 18- T载体上。序列测定和分析表明 ,该片段的核酸序列与国外 TGEV毒株 Miller,Purdue15 ,FS772 /70等有很高的同源性 ,达 96 .88%以上 ,氨基酸同源性为 95 .0 9%以上 ,抗原位点 C(S蛋白第 4 8位氨基酸 )的丝氨酸变为脯氨酸。本研究首次克隆国内分离株 TH- 98株 S基因含有抗原位点 B、C且在 PRCV中缺失的片段。为进一步揭示 TGEV强弱毒株差别的分子机制和分子诊断的研究奠定了重要基础。     

Putative probiotic Lactobacillus spp. from porcine gastrointestinal tract inhibit transmissible gastroenteritis coronavirus and enteric bacterial pathogens

A total of 310 bacterial strains isolated from the porcine gastrointestinal tract were tested for their activity against transmissible gastroenteritis (TGE) coronavirus and other enteric pathogens. Based on activity, the strains Probio-38 and Probio-37 were selected as potential probiotics and identified as Lactobacillus plantarum Probio-38 and Lactobacillus salivarius Probio-37 respectively by 16S rRNA gene sequencing. Supernatants of these strains inhibited TGE coronavirus in vitro in ST cells, without any cytopathic effect even after 72 h of incubation. Both the strains exhibited high survival in synthetic gastric juice. The strains were resistant to 5% porcine bile and exhibited antimicrobial activity against all the 13 enteric bacterial pathogens tested. These strains also exhibited resistance to most of the antibiotics analyzed. The inhibition of transmissible gastroenteritis coronavirus and enteric bacterial pathogens as well as the bile tolerance, high survival in gastric juice, and the antibiotic resistance indicate that the two isolated bacterial strains are ideal probiotic candidates for animal application after proper in vivo experiments.     

猪传染性胃肠炎病毒SC-1株的分离与基因7的克隆分析

从四川某猪场采集疑似病例的腹泻粪样中分离到1株病毒,该病毒经过ST细胞传代培养盲传至第4代时出现病变。通过荧光抗体染色、病毒中和试验、TCID50试验、核酸类型鉴定,结合样品正染后在电镜下的观察结果,确定该毒株为猪传染性胃肠炎病毒,命名为TGEV SC-1株。参照GenBank中收录的TGEV基因7的序列设计了1对特异性引物,以SC-1株的细胞增殖毒的总RNA为模板,通过RT-PCR扩增获得了大小约为303 bp的基因片段,包括完整的基因7序列片段（237 bp）,在GenBank上的登录号为DQ437507。核苷酸和推导的氨基酸序列比较分析结果表明,该毒株与其他毒株的同源性均在92.4%以上,TGEV SC-1株与美国的PURDUE和中国的TH-98毒株亲缘关系最近;与日本各分离毒株、中国TS株、美国Miller株、中国台湾TFI株和英国96-1933株的同源性较低。TGEV基因7在密码子使用的选择上,存在较大的偏向性;基因7编码蛋白在两端存在有明显的疏水性区域,在2～24和56～75位氨基酸残基处存在跨膜结构。