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本试验对由患慢性奶牛乳房炎奶样中分离出的1株疑似金黄色葡萄球菌小菌落突变株(SCVs)进行形态观察、金黄色葡萄球菌相关保守基因片段(nuc、nucA、16S rDNA) 多重PCR扩增鉴定、药敏试验、生理生化特性研究及补偿试验。结果显示分离出1株金黄色葡萄球菌SCVs,该菌含有金黄色葡萄球菌菌种特异性基因nuc和nucA;与金黄色葡萄球菌质控菌株ATCC 25923的抑菌圈大小明显不同;菌落形态主要表现为菌落细小、生长缓慢、溶血能力下降;凝固酶活性下降;耐盐能力降低;革兰氏染色为革兰氏阳性球菌,呈葡萄状排列;补偿试验鉴定该金黄色葡萄球菌SCVs为胸腺嘧啶依赖型。结果表明成功分离鉴定出1株胸腺嘧啶依赖型金黄色葡萄球菌SCVs,为由金黄色葡萄球菌SCVs引起的奶牛慢性乳房炎的预防和控制及其致病机制的研究奠定前期基础。 相似文献
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《中国兽医杂志》2019,(4)
为进一步对西藏牦牛巴氏杆菌病基因组学研究提供理论基础,从西藏林芝某地病死牦牛肺脏中分离鉴定出1株荚膜A型牦牛巴氏杆菌,并通过SMRT法对该菌株进行全基因组序列测定,对测序数据组装后基因组组分及比较基因组学进行分析。结果显示,获得大小为2.3 Mb基因组,GC含量40.30%。同时预测2 096个编码基因数量,编码基因序列总长度2 047 410 bp。预测出总长度为4 739 bp的重复序列,重复序列含量0.21%。预测非编码rRNA数量为19、tRNA数量为59。假基因数量为3,假基因总长度为736 bp。此外,对测序的1株菌株和2株参考菌株(Mannheimia haeemolytica、Pasteurella multocica)进行基因组共线性分析,显示测序菌株与参考菌株之间共线性良好。对测序的1株菌株和2株参考菌株进行家族分类,共得到2 105个基因族,其中,3株菌共有的基因族类(核心基因族)有1 483个,占总基因组的70.45%。进化分析研究显示,测序菌株与参考菌株Mannheimia haeemolytica较远。表明本研究对西藏牦牛巴氏杆菌分离菌株进行全基因测序,同时进行基因组组分及比较基因组学分析,为牦牛巴氏杆菌病的进一步研究提供数据支持。 相似文献
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小菌落突变株（small colony variants,SCVs）是细菌正常生长周期中的一种细菌亚群,它在各种不利条件下可被选择出现。其生化特征表现为生长缓慢、菌落形态不规则、生化特性异常,这使得SCVs的分离鉴定较困难。临床上,SCVs可引起慢性持续性感染,而不引起宿主强烈的免疫反应,且对抗菌药物产生严重的耐药性。文章对SCVs在临床上的表型分类、与宿主免疫反应的关系及抗菌药物对其影响进行综述,以期为SCVs的深入研究提供理论支持。 相似文献
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《畜牧兽医学报》2018,(11)
旨在筛选具有高自然转化效率的副猪嗜血杆菌(HPS)菌株,为自然转化机制及基因功能研究提供生物材料;对所得菌株进行全基因组测序,通过比较基因组分析,挖掘HPS自然转化发生的分子背景。本研究采用自然转化方法对75株HPS田间分离株及15株标准株进行自然感受态菌株的筛选,并测定各自然感受态菌株的转化效率。采用PacBio三代测序技术对具有高自然转化效率的HPS菌株SC1401进行全基因组测序,对测序数据进行组装、基因预测、功能注释及共线性分析。将SC1401株测序结果与NCBI发布的SH0165(CP001321)、SH03(CP009158)、KL0318(CP009237)和ZJ0906(CP005384)进行全基因组比对。结果如下:1)共筛选出11株HPS自然感受态菌株,均为野生型,其中SC1401菌株自然转化效率最高;2)全基因组测序结果显示SC1401菌株整个基因组大小为2 277 540bp,GC含量为40.03%,共编码2 220个基因,占整个基因组序列的87.75%(序列已上传至GenBank数据库,登录号为CP015099);3)基因组共线性分析表明SC1401与其他四株全基因组测序菌株的共线性良好;4)比较基因组分析表明,SC1401菌株含特有基因385个,远多于其他4株菌株所含有的特有基因;5株HPS含有一系列相同的与自然转化相关的基因,且除tfox基因外,各基因氨基酸序列一致性均达90%以上。本研究首次报道了一株强自然转化能力的副猪嗜血杆菌SC1401的全基因组序列,并分析了其基因组基本特征,为后续HPS自然转化机制的研究提供一定理论基础。 相似文献
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金黄色葡萄球菌(Staphylococcus aureus)是导致奶牛乳房炎的主要病原菌,其在抗菌药物的作用下可形成小菌落突变株(small colony variants,SCVs)。为了探讨牛源性金黄色葡萄球菌在表型转变过程中的遗传基础,对临床分离的奶牛乳房炎金黄色葡萄球菌野生型及其SCV、人工诱导的SCV、临床SCV的表型回复株进行了相关特性及基因组序列的分析。结果发现:金黄色葡萄球菌的SCV和野生型差异显著,野生型菌株在庆大霉素及磺胺甲噁唑/甲氧苄啶(SXT)的诱导下绝大多数产生甲萘醌缺陷型SCV,仅有1株经SXT诱导产生的SCV为胸腺嘧啶核苷(胸苷)缺陷型。菌株基因与表型之间存在明显关联,与野生型基因组相比,临床SCV均显示喹啉/醌代谢相关基因menA的碱基缺失,可能导致蛋白表达提前终止。庆大霉素诱导的SCV在基因menB处出现碱基位点突变;SXT诱导的SCV在代谢相关基因MW1485和aroA处分别出现基因片段的缺失和插入。回复株可能通过在代谢相关基因menA二次突变来恢复功能。本研究首次利用全基因组测序技术分析牛源性金黄色葡萄球菌SCV表型改变的遗传基础,有助于对奶牛乳房炎金黄色葡萄球菌SCV产生更深入的理解。 相似文献
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福建省14株PRRSV-2全基因组特性分析 总被引：1，自引：0，他引：1
《中国预防兽医学报》2019,(9)
为了解福建省PRRSV的流行情况及分子特征,本研究选取14株不同年份不同谱系的PRRSV-2(lineage 3、lineage 8.7、lineage 5.1和lineage 1)进行全基因组扩增并测序分析。结果显示,福建省14株PRRSV-2基因组全长为15 016 bp～15 407 bp,与VR-2332、CH-1a、JXA1和NADC30的核苷酸序列同源性为82.9%～99.4%,14株PRRSV-2之间核苷酸序列同源性为82.1%～99.3%,差异较大。分离株FJCH、FJZH与JXA1-R疫苗株高度同源(99.5%～99.6%),且处于同一进化分支,推测其可能来源于疫苗株。重组分析显示14株PRRSV-2存在较高的重组概率(3/14),均发生在lineage 8.7和lineage 1之间。本研究为科学防控福建地区PRRS提供了参考数据。 相似文献
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《畜牧与兽医》2014,(9):90-93
应用PCR方法对采自贵州长顺、清镇和仁怀地区疑似断奶仔猪多系统衰竭综合征的病料进行了猪圆环病毒2型(PCV2)全基因组扩增、克隆和测序分析。结果表明:所扩增克隆的3株PCV2中,GZ-QZ1(JQ809463)和GZ-RH1(JQ809464)2个PCV2毒株基因组全长为1 767 bp,GZ-CS1(JQ809462)株为1 768 bp;3株PCV2之间的核苷酸序列相似性介于94.5%99.9%,与国内外参考毒株核苷酸序列相似性为93.6%99.9%,与国内外参考毒株核苷酸序列相似性为93.6%99.9%;全基因组序列比对分析表明,GZ-QZ1和GZ-RH1两个毒株属于PCV2b,GZ-CS1株属于PCV2a。对3株病毒编码Cap蛋白的ORF2基因分析发现,GZ-QZ1和GZ-RH1毒株与GZ-CS1毒株相比在696位缺失了一个碱基A,导致移码突变,使得末端氨基酸序列变由L K P变为L N P R。 相似文献
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为分析鸡马立克氏病病毒(MDV)LMS分离株的分子遗传特性,本研究对该分离株基因组重复区(包括连接长重复区和短重复区的α样序列)进行了测定。LMS分离株基因组的长重复区为11 746 bp,α样序列为997 bp,短重复区为12 431 bp。在重复区内,预测存在43个ORF,与参考病毒株序列相比存在5个变异较大的ORF。重复区的遗传进化分析表明,LMS分离株与国内814株和欧洲pC12-130株亲缘关系较近。LMS分离株在短重复区潜伏相关转录本(LATs)编码序列的预测转录起始位点位置存在缺失;LMS分离株在α样序列内存在一个新的短重复序列。 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