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1.
马立克氏病病毒(MDV)的致病性一直在不断增强中,甚至已出现了能抵抗CV1988/Rispens疫苗的特超强株。本实验室用BAC克隆技术构建了MDV中国野毒株的Meq基因缺失株,显示出在抗马立克氏病方面具有与美国Meq基因缺失株同样有效的保护性免疫效果,而且其自身没有明显的免疫抑制作用。对美国和中国的两个MDV的Meg基因缺失株的优缺点做了比较。  相似文献   

2.
为了解国内鸡群马立克病(MD)毒株目前的流行情况,在我国3个已免疫MD疫苗的白羽肉种鸡场暴发MD的鸡群中,通过临床剖检,组织病理学变化,病毒分离,IFA检测从发病鸡的淋巴细胞中分离到3株马立克氏病毒(MDV),并分别命名为SDAU1501、SDAU1502和SDAU1503。采用PCR方法扩增3株MDV的vIL8、pp38、meq致病基因,所得氨基酸序列与已发表的参考毒株序列进行比较分析,结果显示SDAU1501和SDAU1502的致病基因与强毒株的同源性达到97%以上,具有强毒特征;而SDAU1503的meq基因在第194位具有与CVI988同样的缺失(P),但其没有CVI988中177个核苷酸的插入突变,其具有与弱毒疫苗株的特征。MDV新的变异在不断发生,出现了不同类型的变异株,因此,对MD的流行情况与基因监测应当继续下去;同时,在MDV疫苗的研制更新上还有待于进一步研究。  相似文献   

3.
广西家禽生产连续十多年高速增长 ,成绩喜人。2 0 0 2年全区禽肉产量达 66743 6吨 ,比 2 0 0 1年增加9 98%;禽蛋达 1 4 45 80吨。 2 0 0 2年家禽出栏 461 73 46万羽 ,比 2 0 0 1年增长 1 2 44%。年出栏 1万羽鸡或 5 0 0羽鹅的规模禽场达 440 8个。家禽迅速发展与禽病防制工作紧密相关 ,近年来在禽病学工作者的努力下 ,广西的禽病研究与禽病防制工作取得了较大的成绩 ,本文就近 1 0多年来的研究成果作一回顾 ,并就今后发展方向提些建议。1 病原基因及分子生物学的研究1 .1 马立克氏病病毒广西大学韦平等 ( 2 0 0 2 ) [1] 报道 ,通过对马立克氏病病毒 (MDV)不同致病型致瘤基因meq核苷酸和氨基酸序列进行比较研究 ,结果发现 ,MDV不同致病型的meq基因序列相对比较保守 ,它们相互间核苷酸和氨基酸序列的同源性均在 95 6%~ 99 7%,但是 ,与所有测试的致病性MDV毒株相比 ,二个Ⅰ型疫苗毒CV1 988/Rispens株和 81 4均在阅读框的核苷酸序列中缺失第 5 75~ 5 77位 3个连续碱基 (CAC)...  相似文献   

4.
一株鸡马立克氏病毒的分离鉴定及其主要致病基因分析   总被引:1,自引:0,他引:1  
吉林省某地区鸡马立克氏病(MD)疫苗免疫鸡群暴发MD,从发病鸡羽髓中分离到一株适应鸡胚成纤维细胞生长的马立克氏病毒(MDV)。该毒株感染无特定病原体(SPF)鸡可引起典型的MD临床症状:对非免疫鸡和火鸡疱疹病毒(HVT)疫苗免疫鸡的致病率分别为76%和72%,二者无显著差异,表明HVT疫苗对该毒株不能提供有效保护。通过对该毒株病毒基因组中132bp重复序列、meq基因的核苷酸及推导的氨基酸序列分析,发现该毒株的132bp重复序列的拷贝数、meq基因的变异符合高毒力MDV毒株的特点。  相似文献   

5.
马立克氏病病毒(MDV)的致病性一直在不断增强中,甚至已出现了能抵抗CV1988/Rispens疫苗的特超强株。本实验室用BAC克隆技术构建了MDV中国野毒株的Meq基因缺失株,显示出在抗马立克氏病方面具有与美国Meq基因缺失株同样有效的保护性免疫效果,而且其自身没有明显的免疫抑制作用。对美国和中国的两个MDV的Meg基因缺失株的优缺点做了比较。  相似文献   

6.
meq是鸡马立克病病毒(MDV)最重要的致瘤基因,在马立克病(MD)肿瘤发生中发挥关键作用。同时,它在疫苗株和强毒株之间具有明显的序列差异性。本文利用CRISPR/Cas9基因编辑技术,以MDV疫苗株CVI988/Rispens meq基因为靶点,设计合成gRNA,克隆构建pX459-gRNA质粒,转染CEF并感染CVI988/Rispens,然后对meq基因编辑的病毒噬斑进行克隆纯化,经过PCR扩增、测序分析及IFA鉴定,成功构建1株meq基因编辑的缺失毒株CVI988Δmeq-C7,为后续筛选和鉴定抗MD疫苗株MEQ单抗及鉴别诊断研究奠定了基础。  相似文献   

7.
为了解马立克氏病病毒(MDV)强、弱毒株主要致肿瘤相关基因变异情况,本研究根据MDV GA株基因组序列,设计合成扩增基因组重复区的引物,得到MDV814疫苗株病毒基因组中约26kb的序列片段。与GenBank登录的强、弱毒株进行比较分析表明,扩增的MDV1型814疫苗株的长重复区为12774bp,预测的开放阅读框(ORF)有48个;短重复区为11426bp,预测的ORF有38个。发现了4个MDV814株特有的ORF。814株在编码Meq、RLORF6和23ku的重叠基因内具有类似于疫苗株CVI988的177bp的插入;在RLORF12基因编码区内存在69bp的缺失,该缺失位于病毒复制起始位点内。同时,发现7个814疫苗株特有的氨基酸突变,分布在6个ORF内。单核苷酸多态性(SNP)的鉴定发现,多个基因具有单核苷酸的突变,主要分布于Meq基因,其中氨基酸A115V(丙氨酸-缬氨酸),N142D(天冬酰胺-天门冬氨酸)的变异是814疫苗株所特有的。MDV814疫苗株重复区的基因序列的比较分析将有助于MDV致肿瘤机制的研究。  相似文献   

8.
本研究旨在分离鉴定河南鸡群马立克病病毒(Marek’s disease virus,MDV)流行毒株,了解当前MDV分子进化特征并为鸡马立克病(MD)的有效防控提供参考。根据MDV基因组设计了meq、gE、gI、gB、pp38以及132-bp重复序列基因的特异性引物,应用PCR扩增和DNA测序分析对河南焦作土鸡群8份MD疑似病例进行了确诊,并通过鸡胚成纤维细胞(CEF)盲传培养和间接免疫荧光试验(IFA)分离鉴定了3个流行毒株,分别命名为HNJZ101、HNJZ102和HNJZ103。结果显示,3个MDV分离株均为血清1型(MDV-1)毒株,未发生禽网状内皮增生症病毒(REV)共感染,并且132-bp重复序列基因均为双拷贝。meq、gE和gI基因核苷酸序列比对分析发现,临床病例样本及3个MDV新分离株的meq基因与国内外温和毒或疫苗毒株的meq基因核苷酸序列同源性仅为64.7%~78.8%,但与MDV强毒株的同源性高达98.9%~100.0%;gE和gI基因的核苷酸序列同源性均较高,分别为99.1%~99.9%和99.3%~100.0%。系统发生树分析结果表明,HNJZ101、HNJZ102和HNJZ103与绝大多数此前分离的河南毒株及国内MDV强毒株同处于一个大的进化分支。研究结果表明,3个分离株HNJZ101、HNJZ102和HNJZ103很可能是当前河南土鸡群中流行的致病性MDV-1毒株,其确切的致病型及导致免疫失败的原因仍有待进一步深入研究。  相似文献   

9.
从感染鸡马立克病病毒血清Ⅰ型(MDVⅠ)814株的鸡胚成纤维细胞(CEF)中提取病毒总DNA,以其为模板,根据GenBank中MDVⅠ GA株基因组gE、gI、gp82基因序列,设计并合成3对特异性引物,用PCR方法分别扩增了814株的gE、gI、gp82基因,并将扩增的基因片段克隆到pMD18-T载体中,进行序列测定,应用DNA Star软件分析814株gE、gI、gp82基因核苷酸序列,并与已发表的MDVⅠ毒株序列进行了比较.结果表明,不同MDVⅠ毒株的gE、gI、gp82基因同源性很高,814株与已发表的MDVⅠ毒株的gE、gI、gp82基因核苷酸序列同源性分别在99.4%、98.9%和99.6%以上.  相似文献   

10.
参考GeneBank发表的马立克氏病病毒(MDV)国际标准强毒株GA的基因序列,设计合成一对引物,分别以RBIB,814,GD2(广东分离株),J-1-E(北京分离株),Md11,Md5,CV1988等不同毒株的MDV基因组DNA为模板,通过PCR扩增,获得了预期大小的PCR产物。该产物经pGEM-T-easy克隆后测序,将所得序列进行比较分析。结果发现:不同毒株间pp38基因的启动子和增强子序列间有缺失突变,序列的同源性大于95.9%,其中大多数的突变发生在MDV复制的原点附近。  相似文献   

11.
本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。  相似文献   

12.
用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10~0.82μg/g。表明:蜂蜜应视为天然富硒营养品。  相似文献   

13.
乳酸杆菌益生作用机制的研究进展   总被引:2,自引:0,他引:2  
乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和 Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。  相似文献   

14.
以国际标准强毒R株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离MG,并收集感染鸡所产蛋分离MG。结果表明,人工感染48小时后上、下呼吸道及肺已被全面感染,96小时气囊已被感染,120小时输卵管已能分离到MG,卵巢始终分离不到MG。人工感染鸡自144小时便能在其所产蛋中分离出MG。药物治疗能在72小时内消除感染,油乳剂苗则需24天后逐渐降低蛋内MG分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内MG,但以研制的种蛋浸泡剂药浴效果为最好。  相似文献   

15.
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。  相似文献   

16.
Reasons for performing study: Clinical experiences indicate that centesis of the lateral compartment of the femorotibial joint is often unsuccessful. Objective: To determine the accuracy of 2 published and 2 unpublished techniques of centesis of the lateral compartment of the femorotibial joint. Hypothesis: It was hypothesised that a drug can be administered into the lateral compartment of the femorotibial joint via a diverticulum of this joint that surrounds the medial aspect of the long digital extensor tendon and that this technique is more accurate than described techniques of centesis of this compartment. Methods: Twenty‐four stifles of 12 horses were divided equally into 4 groups and a radiocontrast medium injected into the lateral compartment of the femorotibial joint of each group using a hypodermic needle inserted: 1) caudal to the lateral patellar ligament and proximal to the tibial plateau, 2) caudal to the long digital extensor tendon and proximal to the tibial plateau, 3) between the long digital extensor tendon and bone of the extensor groove of the tibia or 4) directly through the long digital extensor tendon until it contacted bone. Twelve veterinary students who had no experience using any of these techniques performed the injections. Accuracy of each technique was determined by examining radiographs obtained after injecting the contrast medium. Results: The most successful technique for arthrocentesis was by inserting a needle through the long digital extensor tendon. This approach was successful in all attempted cases, whilst other techniques had lower rates of success. Conclusions: The lateral compartment of the femorotibial joint can be accessed accurately by inserting a needle through the long digital extensor tendon as it lies within the extensor groove. Other techniques may not be as accurate for clinicians inexperienced in arthrocentesis of the lateral compartment of the femorotibial joint.  相似文献   

17.
本试验旨在研究两种绿头鸭(白羽绿头鸭和绿头鸭)肌肉营养组成和价值,为绿头鸭肉产品的开发利用提供基础数据和理论依据。选择白羽绿头鸭和绿头鸭60只(每个品种各30只,公母各半),依照国家标准测定胸肌粗蛋白质、粗脂肪、胆固醇含量及氨基酸、脂肪酸、微量元素和维生素的组成和含量,并对胸肌进行氨基酸评价及脂肪酸营养价值评价。结果显示,白羽绿头鸭肌肉粗蛋白质含量显著低于绿头鸭(P<0.05);两种绿头鸭肌肉中均检测到17种含量大于0.01%的氨基酸,其中白羽绿头鸭肌肉苏氨酸、组氨酸、丝氨酸和脯氨酸含量显著高于绿头鸭(P<0.05),赖氨酸、谷氨酸和精氨酸含量显著低于绿头鸭(P<0.05);检测到13种含量均大于0.01%的脂肪酸,其中白羽绿头鸭硬脂酸和油酸含量显著低于绿头鸭(P<0.05);检测到9种矿物质元素(钠、镁、钾、钙、锰、铁、铜、锌和硒),两种绿头鸭差异不显著(P>0.05);检测到8种维生素,白羽绿头鸭肌肉维生素B1含量显著高于绿头鸭(P<0.05),维生素D和维生素E含量显著低于绿头鸭(P<0.05)。两种绿头鸭肌肉氨基酸比例接近世卫组织推荐的理想模式,富含人体所需的矿物质元素和维生素,具有广阔的开发利用前景。  相似文献   

18.
This experiment was aimed to study the nutritional content and value of the muscles of two mallards (White feather mallard and mallard),and provide basic data and theoretical basis for the development and utilization of mallard meat products.60 White feathered mallards and mallards (30 for each breed,half of male and female) were chosen,and the composition and content of pectoral muscle crude protein,crude fat,cholesterol,amino acids,fatty acids,trace elements and vitamins were determined according to national standards and the nutritional values of muscle were evaluated.The results showed that the content of crude protein in muscle of White feather mallard was significantly lower than that of mallard (P<0.05).17 kinds of amino acids with contents higher than 0.01% were detected in the muscles of the two kinds of mallards,among which the contents of threonine,histidine,serine and proline in the muscles of the White feather mallard were significantly higher than those of mallard (P<0.05).The contents of lysine,glutamate and arginine were significantly lower than those of mallard (P<0.05).13 kinds of fatty acids with contents higher than 0.01% were detected,and the contents of stearic acid and oleic acid were significantly lower than those of the mallard.9 mineral elements (sodium,magnesium,potassium,calcium,manganese,iron,copper,zinc and selenium) in two kinds of mallards were detected,and there was no significant difference between the two kinds of mallards (P>0.05).8 kinds of vitamins were detected,and the content of vitamin B1 in muscle of White feather mallard was significantly higher than that of mallard (P<0.05),but the contents of vitamin D and vitamin E were significantly lower than that of mallard (P<0.05).The ratio of amino acids in muscle of two kinds of mallards was close to the ideal model recommended by WHO,which was rich in mineral elements and vitamins for human body,and had a broad prospect of development and utilization.  相似文献   

19.
应用光镜和透射电镜技术,观察了3~6月龄比格犬甲状腺的显微和超微结构。结果表明,比格犬甲状腺实质由滤泡和滤泡旁细胞构成。滤泡呈圆形或椭圆形,直径20.22~220.00μm,平均90.80μm;由单层立方上皮细胞围成,细胞高度3.04~7.11μm,平均5.18μm,电镜下可见功能状态不同的两型滤泡上皮细胞;滤泡旁细胞很多,直径4.40~8.82μm,平均6.23μm,位于滤泡之间或镶嵌于滤泡上皮细胞之间,也可聚集在一起形成滤泡样结构,胞质内含有大量的分泌颗粒,电镜下也可见两种类型的滤泡旁细胞。  相似文献   

20.
A retrospective review of records of 205 cats with histologically confirmed disease of the spinal cord was performed to identify the prevalence of disease in this nonrandomly selected population of cats. Clinical records were reviewed, and age, duration of neurologic illness, and clinical and histopathologic findings in cats with spinal cord disease were abstracted. Disease processes were classified into 7 categories and 23 groups. The most common diseases affecting the spinal cord of cats were feline infectious peritonitis (FIP), lymphosarcoma (LSA), and neoplasia of the vertebral column secondarily affecting the spinal cord. Information on age, onset and duration of clinical signs, and lesion localization at the postmortem examination in cats belonging to the 7 categories of disease were analyzed to create a practical list of differential diagnoses. Cats were also subcategorized into 3 groups based on their age at death. FIP was the most common disease of cats younger than 2 years of age. LSA and vertebral column neoplasia were the most common diseases affecting cats between 2 and 8 years of age. Vertebral column neoplasia was the most common disease affecting cats older than 8 years of age. Results of this histopathologic study showed that FIP and LSA were the most common disease processes affecting the spinal cord of cats. However, at least 21 other groups of diseases and their relative prevalence were identified.  相似文献   

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