反转录差异显示技术及其方法的改进

运用mRNA反转录差异显示技术可以了解不同细胞或同类细胞在不同发育阶段、不同生理状态下的基因表达状况 ,为研究生命活动过程提供重要信息。文章对差异显示反转录聚合酶链式反应技术的基本原理 ,优点与缺点 ,以及近年来对该技术涉及的RT PCR方法、引物设计、PCR反应参数、电泳及差异条带的显示方法以及杂交方式进行了论述和评价 ,并对其应用前景进行了简单分析。     

mRNA差异显示技术的优化及其在苏淮猪育种中的应用

运用mRNA差异显示技术可以了解不同组织细胞或同类组织细胞在不同发育阶段、不同生理状态下的基因表达状况,为研究生命活动过程提供重要信息。本文对差异显示技术的基本原理、优缺点以及近年来此方法的改进进行了论述和评价,对其方法提出了优化方案,并初步就初步报道了其在苏淮猪的分子标记辅助选育实践中的应用效果。     

mRNA差异显示技术及其在动物遗传研究中的应用

mRNA表达水平的变化决定细胞的功能状态,mRNA差异显示技术是在转录水平上研究基因表达的有效方法,本文综述了mRNA差异显示技术的基本原理方法、PCR引物设计及其循环参数优化、克服假阳性方法的建立,以及其在动物遗传研究中的应用现状,并对其前景进行了展望。     

mRNA差异显示技术及其在家蚕研究上的应用

mRNA差异显示技术是近年发展起来的研究基因表达差异的有效方法。本简述了mRNA差异显示技术的基本原理、技术改进以及此技术在家蚕研究中的应用。     

mRNA差异显示技术及其改进

分子生物学的首要任务之一就是比较不同细胞间或同一细胞不同时间与空间基因表达的差异。在多种基因检测技术中 ,mRNA差异显示技术作为研究细胞、组织在不同条件下 ,基因表达水平差异的重要手段 ,以不可替代的优势已被广泛用于生物学领域。该技术与传统的消减杂交等方法进行比较具有简便、快捷、灵敏、高效等优点 ,但也存在假阳性率高、易污染等缺点。为了克服以上缺点又不断涌现出一些改进技术。文章对该技术的原理、优势与不足及主要改进进行了综述     

mRNA差异显示技术及其在猪基因组研究中的应用

差异显示是一种快速分离、鉴定不同细胞类型基因表达差异的有效方法。此技术自建立以来便广泛应用于比较研究中 ;本文简要介绍了有关差异显示的原理及在猪基因组研究中的应用     

抑制性差减杂交技术(SSH)及其研究应用进展

高等生物大约含有 10万个不同的基因 ,其中仅有 15 %即 15 0 0 0个表达 ,基因表达的变化是调控细胞生命活动过程的核心机制 [1 ] 。因此 ,通过比较同一类细胞在不同生理状态下或在不同生长发育阶段的基因表达差异 ,可为分析生命活动过程提供重要信息。生物体几乎所有的生命活动过程包括病理的变化 ,从本质上讲均是基因表达变化的结果。因此 ,关于真核生物发育过程中基因表达与调控的研究已引起人们的高度重视。过去 ,人们对差异表达基因的分离主要依赖于示差筛选和差别杂交技术 ,但它们又存在着重复性差、敏感度低等缺点。近几年 ,随着 PC…     

牛体外受精早期胚胎发育基因差异表达的研究

应用mRNA差异显示技术,对牛卵母细胞、体外培养的牛早期8细胞期和囊胚期胚胎的基因表达进行了研究。选取4条mRNA表达量存在差异的基因条带进行测序和同源性分析,并利用RT-PCR技术粗略检测其在卵母细胞、8细胞和囊胚中的表达水平。结果表明:4个基因分别与核糖体蛋白S4,Y连接1(RPS4Y1)、末端脱氧核苷酰转移酶作用因子2(DNTTIP2)、剪接和多聚腺苷酸化特异因子3(CPSF3)和转录因子AP-2γ(TFAP2C)高度同源。RPS4Y1、DNTTIP2、CPSF3和TFAP2C在牛卵母细胞和早期胚胎发育过程中mRNA表达量存在时间性差异,可能与其参与不同的生理活动有关。     

山羊早期胚胎发育相关基因的克隆

用单胚构建的mRNA差异显示技术,对体外培养的山羊早期2、4、8～16细胞期胚胎的基因表达进行了研究,并筛选到了1条在8～16细胞期胚胎特异表达的条带进行分析。结果表明,该片段与犬细胞周期蛋白B3（CCNB3）基因具有82%的同源性。该基因作用和调控细胞的分裂活动,是羊早期胚胎发育过程中的重要影响因素。     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.