共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
猪圆环病毒2型江西毒株的全基因扩增与序列分析 总被引:2,自引:0,他引:2
猪圆环病毒(porcinecircovirus,PCV)是由Tischer[1]等于1974年在PK-15细胞中发现的。病毒粒子为20面体对称,以滚环方式进行复制,可在PK-15细胞上生长,但不引起细胞病变,现将其归为圆环病毒科(Circoviridae)圆环病毒属。PCV主要由衣壳蛋白和基因组组成,存在两种血清型,即PCV-1和PCV2。PCV-1无致病性,基因组总长为1.759×103bp,包含7个读码框架,广泛存在于猪体各器官组织及猪源细胞中[2~5]。PCV2首先由Allan等[6]从患断奶仔猪多系统衰竭综合征(PMWS)的猪群中分离到,被证明为PMWS的重要病原[7~8]。患猪表现为明显食欲不振、生… 相似文献
3.
猪圆环病毒(Porcine circovirus,PCV)是迄今为止发现的最小的一种脊椎动物病毒。PCV分为无致病性(或PK15源性)的猪圆环病毒Ⅰ型(PCV-1)和有致病性(PMWS源性)的猪圆环病毒Ⅱ型(PCV-2)两个基因型[1-2]。PCV-1广泛存在于猪体内及猪原代细胞系中,无致病性,不能引起细胞病变; 相似文献
4.
猪圆环病毒2型全序列分析及感染性克隆的构建 总被引:1,自引:0,他引:1
猪圆环病毒2型(PCV2)是一种无囊膜的单股负链环状DNA病毒.猪圆环病毒是1974年由德国学者Tischer[1]等首次从猪肾传代细胞(PK-15)的污染物中分离到的,1982年被命名为猪圆环病毒.猪圆环病毒分为两个血清型:PCV1和PCV-2.其中PCV2具有致病性,能引起断奶仔猪多系统衰竭综合征(post weaning multisytemic wasting syndrome,PMWS),并能导致母猪繁殖障碍和引起免疫抑制,给养猪业造成了严重的经济损失,已经引起了世界各国的广泛重视. 相似文献
5.
6.
一个值得关注的病毒病—断乳猪多系统萎缩综合征 总被引:2,自引:0,他引:2
自 1 991年以来 ,在加拿大[1 ] 、美国 [2 ] 、法国 [3 ] 、西班牙 [4]、北爱尔兰 [5 ]、日本 [6 ]等国的猪群中 ,存在一种被称为断乳猪多系统萎缩综合征 ( postweaning multisystemicwasting syndrome,PMWS)的疾病 ,这种新的疾病严重影响猪的生长发育 ,已经引起了国外学者的广泛关注 ,国内也将此病列入重点防制的疾病之一。1 病原特征 PMWS主要是由一种致病性圆环病毒( porcine circovirus,PCV)或 PCV与猪细小病毒 ( porcineparvovirus,PPV)混合感染引起的 ,这种 PCV与 Tisch-er[7] 于 1 974年首先在 PK-1 5细胞中发现的非致… 相似文献
7.
8.
吉林省猪圆环病毒Ⅱ型血清流行病学调查 总被引:1,自引:0,他引:1
猪圆环病毒(porcine circovirus,PCV)为圆环病毒科(Circoviridae)圆环病毒属成员,单股环状DNA病毒,是迄今发现的最小的动物病毒。PCV存在两种基因型,即PCV-1和PCV-2。PCV-1未发现有致病性;PCV-2主要引起仔猪免疫缺陷的断奶仔猪多系统消耗综合症(Post-weaning multisystemic wasting syndrome,PMWS)的病原之一。猪是 相似文献
9.
10.
浅谈猪圆环病毒2型(PCV-2) 总被引:1,自引:0,他引:1
PCV-2是近几年来一种新发现的病毒,它所致疾病能给养猪业带来很大的经济损失。 PCV为圆环病毒科圆环病毒属成员,单股环状DNA病毒。PCV存在两种血清型,即PCV-1(猪圆环病毒1型)和PCV-2(猪圆环病毒2型)。PCV-1经常存在于机体各组织器官和某些传代细胞中,不致病。PCV-2则是引起PMWS(猪断奶后多系统衰竭综合征)的主要病原。据发现,单 相似文献
11.
12.
13.
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
14.
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
15.
家兔作为一种实验动物 ,推动了繁殖技术的发展。本试验通过对不同年龄公獭兔的睾丸进行组织学观察、测定 ,研究精子的发生规律 ,为系统地进行繁殖生理工作提供依据。1 材料与方法选 60日龄、75日龄、90日龄 3个年龄公獭兔各5只 ,用外科手术法摘取两侧睾丸 ,放入 Bouin氏液中固定 ,二甲苯透明 ,石蜡包埋 ,切成 5~ 8μm切片 ,H.E.染色。在显微镜下观察 ,并进行定量组织学指标测定及差异性比较。2 结果和讨论2 .1 睾丸定量组织学指标的测定结果 见表 1。表 1 獭兔睾丸定量组织学指标 μm,个 /精细管60日龄 75日龄 90日龄曲细精管… 相似文献
16.
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
17.
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
18.
Fractures of the anconeal process of 5 pigs ranging in age from 4 to 8 months were studied radiographically and histologically. Clinically, animals with a fracture of the anconeal process had a "tight," restricted gait. In pigs at 4.5 months of age, a radiolucent line through the base of the anconeal process was composed of fibrocartilage, fibrous connective tissue, and hyaline cartilage. Subperiosteal proliferation of woven bone was located along the cranial surface of the olecranon, adjacent to the base of the anconeal process. In older animals, the radiolucent line through the anconeal process contained variable amounts of fibrous connective tissue and fibrocartilage. The proliferation of subperiosteal bone at the base of the anconeal process formed a "buttress callus" which retained a radiolucent area between the callus and the proximal surface of the anconeal process. The latter region of radiolucency was continuous with the transversely oriented line that traversed the base of the anconeal process. 相似文献
19.
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