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为弄清陕西杨凌某鸡场种鸡产蛋量突然下降,种蛋孵化率降低,死雏、弱雏增多的原因,通过采集发病鸡脑组织进行SPF鸡胚连续传代、琼脂扩散试验(AGP)、人工感染试验、VP1基因的克隆及序列分析等对病原进行鉴定。结果显示,分离毒YL株与AEV标准阳性血清之间出现特异的沉淀线;在人工感染试验中可见雏鸡有震颤、共济失调等症状,剖检大脑有轻微的水肿和软化;成功克隆出AEV YL株的VP1基因,全长810 bp,编码270个氨基酸残基;与AEV参考毒株VP1基因核苷酸同源性92.0%99.8%,氨基酸同源性为89.3%99.8%,氨基酸同源性为89.3%99.3%;进化树分析表明,YL株与1143株、L2Z株和SX株亲缘关系较近,与VR株、HB株、SD株和NH937株亲缘关系较远。结果表明,分离毒株为禽脑脊髓炎病毒,与AEV已知毒株在进化方面存在一定程度的差异。 相似文献
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通过克隆鹅细小病毒(Goose parvovirus,GPV)分离株VP1-V3非重叠区基因,并对其进行序列分析,为鹅细小病毒感染与疫苗免疫的鉴别诊断奠定理论基础.进行鹅胚病毒增殖,收集尿囊液,提取基因组,参考发表的B株序列,设计合成一对引物,经PCR扩增,克隆VP1-VP3基因,筛选阳性克隆,对其进行序列测定及同源性分析.结果表明,克隆的基因片段为901 bp,VP1-VP3基因共594 bp,编码198个氨基酸;弱毒株之间亲缘关系很近,核苷酸同源性99.5％～100％,氨基酸同源性98.5％～100％;强毒株与B株亲缘关系较近,核苷酸同源性96.6％,氨基酸同源性97.5％;弱毒株与强毒株亲缘关系较远,核苷酸同源性92％～93％,氨基酸同源性96％～97.5％;弱毒株与B株亲缘关系最远,核苷酸同源性92.5％～93％,氨基酸同源性93.9％～95.5％.说明强毒株与弱毒株之间核苷酸序列存在差异. 相似文献
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利用反转录-聚合酶链式反应(RT-PCR)技术及RACE方法扩增得到鸭肝炎病毒(DHV)浙江分离株Z10的全基因(5',3'末端序列用RACE法扩增)及4株DHV分离株的VP1基因.结果表明,分离株Z10的全基因片段长7689 bp,有1个大的开放读码框(ORF),ORF位于626～7326位核苷酸,编码2249个氨基酸.Z10分离株全基因序列与GenBank登录的6株具有代表性的DHV核苷酸序列比对,同源性94.5%～98.4%;所测得的DHV分离株的VP1基因的序列与目前GenBank上发表的具有代表性的DHv-Ⅰ VP1基因进行比对分析,结果4株Ⅰ型DHV的VP1基因cDNA长度均为714 bp,编码238个氨基酸.4株DHV-Ⅰ之间VP1基因的核苷酸序列同源性为93%～99.7%,氨基酸序列同源性为95.0%～100%;与参考毒株VP1基因的核苷酸序列同源性为92.2%～100%,氨基酸序列同源性为95.0%～100%;表明各分离毒株的亲缘关系较近,属于同一基因群. 相似文献
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《中国兽医学报》2017,(7):1249-1254
采集患病雏鸡脑组织样品制成组织悬液进行SPF鸡胚传代,通过免疫组化试验、动物试验、RT-PCR扩增VP1基因片段对病原进行鉴定,并对基因序列进行遗传进化分析,结果分离了1株禽脑脊髓炎病毒(AEV),命名为XY13株。免疫组化结果显示脑组织切片中存在大量的深棕黄色着色区域;动物试验中雏鸡出现了震颤、共济失调等禽脑脊髓炎(AE)临床症状,剖检发现脑组织软化、有散在出血点;RT-PCR扩增出的目的片段长度为288bp,编码96个氨基酸;序列分析表明AEV XY13株分离株与参考毒株的核苷酸同源性为74.6%~99.7%,氨基酸同源性为76.0%~97.9%;进化树分析表明AEV XY13与SX株的处于相同的分支,与1143、YL、L2Z株同处于一个较大的分支上,而与VanReokel、NH-937和204C株则处于不同的分支上,表明亲缘关系较远;进化距离预测结果表明AEV XY13株与1143、L2Z、SX和YL株的进化距离均小于0.011,而与NH-937、Van Reokel和204C株的进化距离则大于0.060。结果表明:本分离株为AEV,与目前已知的AEV毒株在进化关系上存在一定的差异。 相似文献
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禽脑脊髓炎病毒VR株衣壳蛋白基因的克隆及序列分析 总被引：3，自引：0，他引：3
用冻存的禽脑脊髓炎病毒Van Roekel(AEV VR)株通过SPF鸡胚传代复壮，获得了试验用病毒株样本。根据已知禽脑脊髓炎病毒1143(AEV 1143)株的衣壳蛋白VP0、VP3、VPl基因序列，设计了3对引物，分别扩增AEV VR株的VP0、VP3、VP1基因，将RT-PCR产物进行分子克隆和序列分析。结果表明，AEVVR株与AEV1143株VP0、VP3、VP1基因的核苷酸同源性分别为95．1％、93．6％和93．9％；氨基酸的同源性分别为97．57／6、97．5％和99．6％。 相似文献
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猪繁殖与呼吸综合征病毒 Nsp10基因的克隆及序列分析 总被引：1，自引：0，他引：1
根据猪繁殖与呼吸综合征病毒 BJ-4序列,选择Nsp10基因保守区域设计并合成特异性引物,用RT-PCR方法扩增出猪繁殖与呼吸综合征病毒贵州地方株(命名为JL株)Nsp10基因片段,克隆到pMD18-T载体并测序,应用DNASTAR、Clustal_1.81和Mega序列分析软件进行同源性比较.结果表明:贵州JL株Nsp10基因的cDNA长699 bp,可编码233 个氨基酸;贵州JL株Nsp10基因与早期分离毒株MLV株、BJ-4株、VR-2332株、CH-1a株、CH2002株和GS2004株相应序列的核苷酸同源性为 91.7%～94.0%,氨基酸同源性为97.4%～98.7%;而与最近分离毒株HN2007株、SX2007株、GD2007株、YN2008株、GS2008株、XL2008株、TJ株和JXA1株的核苷酸同源性为 98.3%～98.6%,氨基酸同源性为 99.6%～100%. 相似文献
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以3株国内分离的O型口蹄疫病毒(FMDV)(分别命名F1、F2、F3)为研究目标,根据GenBank中注册的FMDV VP1基因的序列设计2对引物,采用RT-PCR方法成功地扩增出含有VP1全基因的cD-NA片段,将3个cDNA片段分别克隆到pMD20-T Vector载体中进行序列测定,得到3个毒株VP1基因的序列。结果表明,3个O型FMDV毒株VP1基因cDNA长度均为639 bp,编码213个氨基酸。3株O型毒株彼此之间的核苷酸序列同源性在92.3%~94.2%之间,推导氨基酸序列同源性在97.2%~98.6%之间。与3个毒株同源性高的主要为香港和台湾的毒株。 相似文献
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为了对鸡传染性法氏囊病病毒(IBDV)的13个地方分离株与3个商品疫苗株的VP1-b基因(756 bp～1 522 bp)进行同源性和遗传进化分析,本研究对其进行RT-PCR扩增和序列测定.结果表明,获得的VP1-b基因长度均为767 bp; 13个分离株VP1-b节段核苷酸和氨基酸同源性分别为90.7 ％～100％和72.9％～100％,其中10株超强毒分离株与经典株、弱毒株、疫苗株的同源性较高,核苷酸和氨基酸同源性分别为95.7％～100％和94.5％～100％,所有12个超强毒分离株与超强毒参考病毒株的同源性均较低,核苷酸同源性仅为68.2％～79.2％;在遗传进化分析中,所有病毒株被分为3个分支,与相应病毒株的基于IBDV-VP2高变区(vVP2)序列的遗传进化树比较并结合同源性分析结果表明,除了弱毒株HUN0804之外,其它12个分离株可能均为重组病毒.据此推测,基因重组可能是目前IBDV流行的新趋势. 相似文献
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为了解河北省塞内卡病毒A(SVA)VP2基因的变异及分子进化情况,试验设计了一对VP2基因扩增引物,通过RT-PCR方法扩增和克隆测序,利用MEGA 7.0软件对测序获得的VP2基因序列和GenBank上的参考序列进行遗传进化分析,运用MegAlign 5.0软件进行核苷酸和氨基酸同源性分析。结果表明：成功扩增并测序得到VP2基因序列,将该序列上传至GenBank,获得基因登录号为MZ031967,命名为SVA HB-BD株。该毒株与中国毒株核苷酸序列相似性为95.9%～99.6%;与原型毒株SVV-001(DQ64125-7核苷酸)相似性较低,为94.6%;与其他美国毒株(MN812946、MN812947、KC667560、MH704432、MN812938、MN812937、KU954086、NC011349)核苷酸相似性为93.0%～94.6%。SVA HB-BD株与2015—2016年分离毒株亲缘关系较近,处于同一分支,而与2017—2018年分离毒株亲缘关系较远。SVA HB-BD株与广东省分离毒株氨基酸序列相似性较高,并且在VP2蛋白中和表位位点高度保守。说明HB-BD株... 相似文献
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根据基因库中新城疫病毒M基因核苷酸序列,设计一对特异性引物,对2000年-2003年期间广西分离的11个NDV毒株的M基因进行RT-PCR扩增、克隆和序列测定.结果表明,11个NDV广西分离株的M基因都为1 223个核苷酸,含有1个1 095 bp核苷酸阅读框(ORF),编码364个氨基酸.序列分析结果表明,这11个NDV分离株核苷酸的同源性在86%～99.9%之间,推导氨基酸的同源性在89.3%～99.7%之间;11个毒株与国内外其他7个NDV毒株比较核苷酸的同源性在83.3%～98.5%之间,推导氨基酸的同源性在87.4%～98.6%之间. 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
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
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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
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
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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
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Billinghurst RC Brama PA van Weeren PR Knowlton MS McIlwraith CW 《American journal of veterinary research》2004,65(2):143-150
OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis. 相似文献