小尾寒羊S100A1基因编码区外显子克隆及表达分析

本研究旨在探索小尾寒羊S100钙结合蛋白A1(S100 Calcium Binding Protein A1,S100A1)基因结构、突变位点以及在各组织和脂肪细胞不同阶段的表达差异.通过荧光定量PCR检测S100A1基因在3日龄小尾寒羊脂肪组织及6月龄脂肪、肌肉、肺、脾、肠、心、肝组织的表达差异;体外克隆S100A1...     

由H7N9引发的对人兽共患病的思考

近年来人兽共患病频发,在2013年H7N9给人类带来了极大的恐慌,引起了国内外高度关注。文章就人兽共患病的概念、分类、频发的原因和防控措施进行了介绍。     

鸡组织滴虫病PCR病原学诊断方法的建立

为建立鸡组织滴虫(H.meleagridis)的PCR检测方法,本研究以确诊的感染火鸡组织滴虫的阳性鸡的肝组织DNA为模板,设计针对18S rRNA基因高度保守的特异性引物,建立组织滴虫病的PCR诊断方法。敏感性试验显示阳性样品组织DNA的最低检出限为4 ng/μL。特异性试验表明与其他常见鸡寄生虫的DNA样品均无交叉反应。该PCR方法对临床样品的检出率为100%,与组织病理学诊断结果符合率为100%。该诊断方法敏感、特异,可以用于组织滴虫病的临床诊断。     

豚鼠气单胞菌引起山羊猝死的鉴定

2020年5月,江苏省某养殖场饲养的220只山羊疑似感染产气荚膜梭菌,共死亡25只。为鉴定感染的产气荚膜梭菌复合群类型,采集大肠、小肠内容物以及肠系膜淋巴结、肝、脾、肾等组织病料进行细菌分离鉴定,并对分离菌株进行药敏试验及致病性试验。结果显示：分离菌株为革兰氏阴性短杆菌,经生化试验和16S rRNA试验鉴定为豚鼠气单胞菌;该分离株对多种常用抗菌药物耐药,仅对呋喃唑酮敏感;该菌能造成小鼠发病死亡。此次从临床发病羊病料中分离到致病性豚鼠气单胞菌,在国内较为少见,截至目前未见类似报道,本研究为避免此类疫病的临床误诊以及做好该病防控提供了帮助。     

东方田鼠肝脏T7噬菌体展示cDNA文库的构建

本项研究的目的是构建东方田鼠肝脏T7噬菌体展示cDNA文库,为筛选东方田鼠抗血吸虫病抗性相关基因奠定基础.用TRIzol试剂提取东方田鼠肝脏总RNA,分离纯化mRNA,经反转录合成双链cDNA.在双链cDNA末端加上EcoRⅠ/HindⅢ定向接头并用EcoRⅠ和Hind Ⅲ酶切,使其两端分别带EcoRⅠ和HindⅢ粘性末端.用Mini Column纯化、收集300 bp以上的双链cDNA片段,再连接于带有EcoRⅠ和HindⅢ末端的T7 Select 10-3b载体,经体外包装后,以BLT5403为受体菌构建T7噬菌体展示cDNA文库.经测定,库容量为1.3×107 PFU/mL,扩增后文库滴度为1.8×1011 PFU/mL.对从原始文库中随机挑取的100个噬菌斑进行PCR鉴定,重组率为91.7%,阳性克隆片段大小分布在200 bp～1 000 bp,其中有95.5%的插入片段大于300 bp.用日本血吸虫童虫可溶性抗原对文库进行了初筛,得到了21个ESTs,将这些阳性噬菌体克隆和血吸虫童虫共培养,其中大部分克隆诱导的童虫死亡率比阴性噬菌体对照高出2%～13%.     

抗热应激中草药添加剂(夏安散)对奶牛产奶量和血液生化指标的影响

选择30头泌乳奶牛,根据胎次相同、泌乳日相似、上胎产奶量相近、健康无病等因素采用随机区组设计分成2组:试验组(饲料中添加中草药方剂200 g/(d.头),分2次饲喂)和对照组,试验期45 d,探讨中草药添加剂对奶牛产奶量及血液生化指标的影响。结果表明:添加中草药方剂的奶牛在试验期间每头牛的日产奶量比对照组提高18.89%(P<0.01),停药后2个月比对照组提高21.42%(P<0.01);对乳糖、乳脂、乳蛋白没有显著影响(P>0.05);红细胞总数、血红蛋白含量比对照组分别提高10%、16%(P<0.05);血清钾、钙离子升高27.45%和11.26%(P<0.01);血清总蛋白、球蛋白比试验前升高3.38%和10.26%(P<0.05)。     

肠出血性大肠杆菌O157 ler基因缺失突变株的构建及其特性

以肠出血性大肠杆菌O157∶H786～24为始发菌株,利用自杀性载体pCVD442,根据同源重组的原理敲除了染色体上的ler基因,构建了O157∶H7 ler基因缺失突变菌株,并对其生物学特性进行了初步研究。荧光定量PCR试验结果表明,始发菌株对HEp-2细胞的平均黏附数量是突变菌株的17倍。试验也证实了ler基因对LEE致病岛毒力基因的正调控作用,这为O157∶H7基因缺失突变弱毒疫苗株的建立奠定了基础。     

患子宫内膜炎母驴与健康母驴的阴道菌群差异分析

为探究患子宫内膜炎母驴阴道病原,本试验从规模化养殖场采集5份患子宫内膜炎母驴病料作为患病组,以6份健康母驴样本作为健康组,采用16S rDNA扩增子测序技术对2个组阴道分泌物样本中的菌群进行比较分析。结果显示,患病组母驴阴道菌群的多样性和丰富度均高于健康组;与健康组相比,患病组母驴阴道变形菌门(Proteobacteria)的相对丰度显著增加,而梭杆菌门(Fusobacteria)、放线菌门(Actinobacteria)和未分类菌门(Unidentified bacteria)显著降低(P<0.05);在属的分类水平上,患病组母驴阴道中链球菌属(Streptococcus)丰度显著高于健康组母驴(P<0.05),链球菌属可能是母驴子宫内膜炎的主要致病菌;在主成分分析上,患病组样本间的微生物群落差异较大,而健康组样品间的微生物组成相似;功能预测上,患病组阴道内微生物的免疫系统(Immune system)和传染性疾病(Infectious diseases)2个功能的相对丰度显著高于健康组,说明阴道内含有大量相关功能的微生物发挥着作用。本试验为母驴子宫内膜炎的后续预防和治疗...     

Study on Biological Characteristics and Drug Sensitivity of Haemophilus parasuis Isolated in Sichuan Province

The study was aimed to investigate the biological characsteristics and drug sensitive tests of Haemophilus parasuis isolated in Sichuan province.This paper reported the biological characteristics,16S rRNA gene PCR and drug sensitive test of the isolates by technique of microbiological and molecular biology.The results showed that the isolates had micro anaerobic and could produce satellite phenomenon,the isolates were just same in biochemical characteristics with field isolates in other area.All the isolates amplified 821 bp 16S rRNA gene.And drug sensitive tests showed that the isolates were highly sensitive to cefradine,ampicillin,cefradine,amoxicillin,cefaclor,ofloxacin,cefotaxime and furadantin,the sensitive rate was 75.61% to 87.80%,but the isolates were high resistance to lincomycin,carbenicillin,enrofloxacin,amikacin and sulfamethoxazole,and multiple-drug resistance was found among the isolates,the number of bacterial strains resistant to antibiotics were more between five and eight,the resisitance strains were 21.95% to 30.49%,7 isolates were even resistant to 13 antibiotics.The results showed the phenomenon of drug resistance of the isolates was very serious.     

Identification and Molecular Characteristics Analysis of Porcine Epidemic Diarrhea Virus Variants

To ascertain a diarrhea case in a pig farm in Shandong province,the pathological changes of dead piglets were observed and nested RT-PCR test was carried out on 7 diarrhea samples for porcine epidemic diarrhea virus (PEDV).Pathological examination revealed that intestine was detected as enlargement,hyperemia and edema.After histological examination,the typical microscopic lesions of intestine were disappearance of epithelial cells,villus shrinkage and shortening.The result of nested RT-PCR showed that all of the 7 samples could amplify a specific target band of PEDV.Molecular characteristics of two field strains showed that they had an amino acid homology of 92.3% to 92.4% with vaccine CV777 and 96.6% to 98.6% with other previous field strains which sequences were downloaded from GenBank.Phylogenetic tree analysis further revealed that all of PEDV strains could be mainly divided into two clusters of G1 and G2. G2 consisted of the field strains of our study and other field strains from USA,China and so on,which had the same sequence characteristics of two insertions and one deletion,while G1 consisted of all vaccines of CV777 and several older field strains from China and Korea.These results indicated that our field strains were the dominant strains in recent epidemic diarrhea occurrence.Moreover,its molecular characteristics might be a characterization of differentiating the field and vaccine strains.