香猪NRAMP1基因多态性与仔猪腹泻的研究

天然抗性巨噬蛋白1(natural resistance associated macrophage protein 1,NRAMP1)基因是与人、鼠的一些病原微生物(如分支杆菌中的沙门氏伤寒菌等)的易感性和抗性有关的重要候选基因。本研究利用PCR-RFLP技术,分析了香猪的NRAMP1基因第6内含子的NdeⅠ酶切位点的多态性;观测记录哺乳仔猪的腹泻情况,结果发现,NRAMP1基因的第6内含子的NdeⅠ酶切位点在各品种猪表现出丰富的多态性,该酶切位点的基因频率和基因型频率在各猪种中分布趋于一致,香猪不同品系基因型与腹泻指数统计分析结果显示,Ⅰ系、Ⅱ系差异不显著,11世代显著高于10世代。     

鸡NRAMP1蛋白序列特征、分子进化与突变分析

为解析鸡天然抗性相关巨噬蛋白1(Natural-resistance-associated macrophage protein 1,NRAMP1)223位Arg突变为Gln对蛋白质结构和理化性质的影响，试验系统分析了鸡NRAMP1蛋白质结构特征，重点比较鸡NRAMP1 223位Arg（抗性）和Gln（易感）的蛋白质理化性质和结构差异，并分析略阳乌鸡NRAMP1基因该位点的多态性。结果表明，NRAMP1蛋白质保守性较高，鸡和人NRAMP1氨基酸序列相似度达68%，以鸡NRAMP1的第223位氨基酸为参考，其他物种该位点均为碱性氨基酸（Arg、Lys、His）；鸡NRAMP1第2 454位G突变为A,223位Arg变成Gln，其理化性质和二、三级结构均发生变化，该位点附近的β-转角变为α-螺旋。略阳乌鸡NRAMP1基因该位点的GG基因型频率为67.1%,GA频率30.1%,AA频率2.7%。研究结果证实鸡NRAMP1蛋白质223位突变改变其结构和理化性质，可能与该蛋白抗感染能力相关。     

NRAMP1基因的研究进展

天然抗性相关巨噬蛋白(natural resistance associated macrophage protein 1,NRAMP1)与多种胞内菌如结核分枝杆菌、沙门氏杆菌和利什曼原虫等易感和抗性相关。综述了NRAMP1基因的结构特点、作用机理、表达调控及其与疾病的相关性,以期为应用于猪的抗病育种提供理论依据。     

苏淮猪群体抗腹泻基因MUC13和FUT1多态性分析及其抗腹泻选育方案研究

腹泻是现代猪场集约化规模养殖过程中常见的疾病,给养殖场带来巨大的经济损失。产肠毒素大肠杆菌F4ac以及F18是导致仔猪腹泻的重要病原微生物,而MUC13和FUT1分别是控制仔猪大肠杆菌F4ac以及F18易感或抗性的主效基因。本试验对淮安市淮阴种猪场的苏淮猪核心群做了MUC13和FUT1基因的多态性检测。结果表明:在整个苏淮猪核心群中MUC13的G等位基因频率较高,其中公、母猪群体分别达到0.625和0.568,有利于苏淮猪抗腹泻性能的选育提高;然而FUT1的A等位基因频率较低,其中公、母猪群体分别为0.250和0.190。根据苏淮猪MUC13和FUT1基因多态性结果,制定了以MUC13基因的选择为主,FUT1基因选择为辅的抗腹泻群体的分子选育方案,以期通过结合常规育种手段来提高苏淮仔猪对腹泻的抗性。     

新民猪和皮民猪ESR基因的多态性检测分析

为了研究新民猪和皮民猪雌激素受体(ESR)基因的多态性,试验采用PCR-RFLP方法,对黑龙江省农业科学院畜牧研究所收集整理的27头新民猪和50头皮民猪F1代的ESR基因进行检测,并与其他已报道的猪种进行比较。结果表明:新民猪ESR基因的A等位基因频率为0.593,B等位基因频率为0.407;皮民猪ESR基因的A等位基因频率为0.720,B等位基因频率为0.280。新民猪与皮民猪的等位基因频率与引进猪种相似,即A等位基因频率略高于B等位基因频率;然而我国大部分地方猪种的B等位基因频率高于A等位基因频率,其中B为优势等位基因。     

贵州地方猪品种与欧洲猪品种MUC13基因的多态性比较

产肠毒素大肠杆菌(Enterotoxigenic Escherichia coli,ETEC)是导致仔猪腹泻的主要病原,MUC13基因被认为是控制仔猪ETEC易感或抗性的候选基因。本文通过等位基因特异性PCR(Allele-specific PCR)方法对4个贵州地方猪种MUC13基因的多态性进行研究,并与两个欧洲猪群相比较。结果显示:贵州地方猪群中MUC13基因的G等位基因频率较高,特别是香猪和黔北黑猪群体分别达到了95.21%和96.43%,与贵州地方猪品种优良的抗腹泻表现相符。提示贵州地方猪品种MUC13基因的G119A位点可以作为抗腹泻筛选的SNP分子标记。     

军牧1号白猪、杜洛克猪、西藏小型猪和大白猪ESR、FSHβ、EGF基因的多态性分布

摘要：ESR、FSHβ和EGF基因与猪繁殖性状密切相关。为检测军牧1号白猪、西藏小型猪、杜洛克猪和失白猪ESR、FSHβ和EGF基因的多态性分布情况,采用PCR和PCRRFLP的方法对61头军牧1号白猪,51头杜洛克猪,51头西藏小型猪和69头大白猪的ESR、FSHβ和EGF基因多态性进行了检测。结果显示,对于各个基因的优势等位基因,在军牧1号白猪群体中,ESR基因位点A等位基因频率为0．6393,FsHp基因的13等位基因频率高达0．9098,EGF基因的A等位基因频率仅有0．0164杜洛克猪群体中,ESR基因A等位基因频率为0．6078,FSHβ基因的B等位基因频率为0．8235,而EGF基因的八等位基因频率仅为0．0297;西藏小型猪群体中,ESR基因A等位基因频率是0．4608,FSHβ基因B等位基因频率仅为0．0687,H;F基因A等位基因频率为o．1961;大白猪群体中。ESR基因位点有频率为0．5000的有害A等位基因,而FSHβ基因和EGF基因的13等位基因频率则分别为0．8013和0．7391。所有基因型分布均符合哈代温伯格平衡（P〉0．05）。     

藏猪天然抗性相关巨噬细胞蛋白基因克隆及变异研究

采用克隆及测序相结合的方法,研究了藏猪、甘肃黑猪、大白猪、约克夏猪和杜洛克五个猪种天然抗性相关巨噬细胞蛋白(natural resistance associated macrophage protein,NRAMP1)基因全序及其结构和变异。分析表明,猪NRAMP1基因全长12779bp,其中包含14个内含子、15外显子,编码区全长1614bp,编码538个氨基酸。5'端非编码区存在2个核苷酸突变,3'端非编码区存在有10个核苷酸突变和1个碱基缺失,14个内含子存在11个变异位点。外显子有18个碱基突变,仅有4个有义突变位点(T2551G、A2552T、C4881A、T12113C),分别导致四个氨基酸(100(V→G)、100(V→G)、137(P→T)、471(L→P))的改变,有可能引起NRAMP1基因编码所蛋白质的跨膜结构域、三级结构或更高级结构以及其空间排列发生变化,导致藏猪和其他猪种抗病性存在差异,为揭示猪NRAMP1基因抗病性的分子机理奠定了理论基础。     

FSHβ和FUT1基因多态性在海南临高猪中的分布

通过PCR、PCR-RFLP方法对70头海南临高猪进行了FSHβ和FUT1基因型检测。结果发现,FSHβ基因在临高猪中存在AA、AB和BB 3种基因型,其中A等位基因频率为0.81,B等位基因频率为0.19。在FUT1基因编码区的Hin6Ⅰ-RFLP位点上,临高猪以GG基因型为主,该位点A等位基因和G等位基因频率分别是0.07和0.93。试验结果为海南临高猪的杂交选育提供理论依据。     

11个猪群体BPI基因第10外显子HpaⅡ遗传变异分析

本研究旨在对猪杀菌性/通透性增加蛋白(BPI)基因的多态性进行系统分析,为今后探讨猪BPI基因与疾病抗性的关系提供理论依据。采用PCR-RFLP方法对野猪和国内外10个猪品种BPI基因第10外显子HpaⅡ遗传变异进行检测及序列分析。结果表明:11个猪品种中共检测到AA、BB和AB 3种基因型,2个等位基因,其中野猪、藏猪、荣昌猪和淮猪群体中AA基因型为优势基因型,A等位基因为优势等位基因;外来商业化猪品种中,杜洛克群体AA基因型频率较高。序列分析表明AA基因型与GenBank中的序列一致,BB基因型存在A27G同义突变位点和T118G错义突变位点。基于BPI基因的等位基因频率构建11个猪群体的系统发生树,第1类群包括野猪、淮猪、藏猪、荣昌猪、杜洛克;第2类包括约克夏、长白猪、枫泾猪、梅山猪、二花脸、苏太猪。本研究结果显示,猪群体间基于BPI基因多态性上存在的差异与体型、生产类型及地理分布等因素没有显著的联系。     

不同品种猪α1-岩藻糖转移酶基因遗传变异初析

本实验采用PCR RFLP方法对 5个瘦肉型猪种杜洛克、长白猪、大白猪、汉普夏猪和皮特兰猪共计 2 5 0头猪的α1 岩藻糖转移酶基因 (FUT1)进行多态性分析。结果表明 :本研究中的 5个猪种在该FUT1基因座位存在多态性 ,均分布着三种基因型 (AA ,AG和GG) ,抗性基因型AA分布频率为 0 .0 2 8,易感基因型AG与GG分布频率分别为0 .2 4 4和 0 .72 8。卡方检验结果表明 ,长白猪与大白猪基因型频率差异极显著 (P <0 .0 1) ,与皮特兰猪之间差异显著(P <0 .0 5 ) ,其它猪种之间差异均不显著。     

猪抗病育种研究进展

猪病给养猪生产造成的经济损失约占总产值的12％～15％,提高猪抗病能力和抗病育种已成为目前研究的热点。作者综述了干扰素基因、NRAMP1基因、肠毒素大肠杆菌、MHC基因等候选基因的研究进展，以期为抗病育种提供借鉴。     

Pathologic findings and association of Mycobacterium bovis infection with the bovine NRAMP1 gene in cattle from herds with naturally occurring tuberculosis

OBJECTIVE: To determine necropsy and Mycobacterium bovis culture results in cattle from herds with tuberculosis, the role of the bovine NRAMP1 gene in resistance and susceptibility to infection with M bovis, and the association between magnitude of the tuberculous lesions and various types of M bovis isolates. ANIMALS: 61 cattle from herds with tuberculosis in Texas and Mexico. PROCEDURE: 61 cattle were evaluated by necropsy; 59 had positive and 2 had negative caudal fold tuberculin intradermal test (CFT) results. Thirty-three cattle with positive CFT results were genotyped to evaluate polymorphism of the 3' untranslated region of the bovine NRAMP1 gene, using single-stranded conformational analysis, 9 were resistant to M bovis with no tuberculous lesions and negative M bovis culture results, and 24 were susceptible with tuberculous lesions and positive M bovis culture results. Isolates of M bovis were analyzed by restriction fragment length polymorphism (RFLP) on the basis of IS6110 sequences and direct-repeat fingerprinting patterns. RESULTS: 21 (35.6%; 21/59) cattle with positive CFT results had tuberculous lesions or positive culture results; in addition, 1 of 2 cattle with negative CFT results had tuberculous lesions and positive culture results. Tuberculous lesions were most common in the thorax (35/63; 55.5%) and lymphoid tissues of the head (10/63; 15.9%). Tuberculous lesions varied from 1 to 11/animal; 8 of 21 (38.1%) had solitary lesions. Associations were not found between resistance or susceptibility to infection with M bovis and polymorphism in the NRAMP1 gene or between the magnitude of the lesions and various RFLP types of M bovis isolates. CONCLUSIONS AND CLINICAL RELEVANCE: The NRAMP1 gene does not determine resistance and susceptibility to infection with M bovis in cattle.     

Genetic variation at the alpha‐1‐fucosyltransferase (FUT1) gene in Asian wild boar and Chinese and Western commercial pig breeds

Escherichia coli F18 bacteria producing enterotoxins and/or shigatoxin (ETEC/STEC) are main pathogens that cause oedema disease and postweaning diarrhoea in piglets, and alpha‐1‐fucosyltransferase (FUT1) gene has been identified as a candidate gene for controlling the expression of ETEC F18 receptor. The genetic variations at nucleotide position 307 in open reading frame of FUT1 gene in one wild boar breed and 20 western commercial and Chinese native pig breeds were investigated by polymerase chain reaction–restriction fragment length polymorphism. The results showed that the genetic polymorphisms of the FUT1 locus were only detected in western pig breeds and the Chinese Taihu (including Meishan pig, Fengjing pig and Erhualian pig), Huai and Lingao pig breeds; only Duroc and Pietrain possessed the resistant AA genotype, while the wild boar and other Chinese pig breeds only presented the susceptible genotype GG. The results indicated that Chinese native pig breeds lack genetic factors providing resistance to ETEC F18 bacteria. The resistant allele to ETEC F18 might originate from European wild boar. It was inferred that oedema and postweaning diarrhoea caused by ETEC F18 have close relationship with the growth rate, which can explain why on the contrary Chinese native pig breeds have stronger resistance to oedema and postweaning diarrhoea in piglets compared with western pig breeds.     

Resistance to ETEC F4/F18–mediated piglet diarrhoea: opening the gene black box

Diarrhoea, a significant problem in pig rearing industry affecting pre- and post-weaning piglets is caused by enterotoxigenic Escherichia coli (ETEC). The ETEC are classified as per the fimbriae types which are responsible for bacterial attachment with enterocytes and release of toxins causing diarrhoea. However, genetic difference exists for susceptibility to ETEC infection in piglets. The different phenotypes found in pigs determine their (pigs’) susceptibility or resistance towards fimbrial subtypes/variants (F4ab, F4ac, F4ad and F18). Specific receptors are present on intestinal epithelium for attachment of these fimbriae, which do not express to same level in all animals. This differential expression is genetically determined and thus their genetic causes (may be putative candidate gene or mutations) render some animals resistant or susceptible to one or more fimbrial subtypes. Genetic linkage studies have revealed the mapping location of the receptor loci for the two most frequent variants F4ab and F4ac to SSC13q41 (i.e. q arm of 13th chromosome of Sus scrofa). Some SNPs have been identified in mucin gene family, transferring receptor gene, fucosyltransferase 1 gene and swine leucocyte antigen locus that are proposed to be linked mutations for resistance/susceptibility towards ETEC diarrhoea. However, owing to the variety of fimbrial types and subtypes, it would be difficult to identify a single causative mutation and the candidate loci may involve more number of genes/regions. In this review, we focus on the genetic mutations in genes involved in imparting resistance/susceptibility to F4 or F18 ETEC diarrhoea and possibilities to use them as marker for selection against susceptible animals.

     

海南五指山猪Myf5与MyoD基因多态性分析

为研究海南五指山猪Myf5和MyoD基因的多态性分布情况,本试验通过PCR-RFLP方法对80头海南五指山猪进行了Myf5和MyoD基因型检测,并运用生物信息学方法对这两个基因的序列进行分析.结果发现,在Myf5基因第1外显子的HhaⅠ-RFLP位点上,五指山猪以CC和CG基因型为主;在Myf5基因第1外显子的Hsp92Ⅱ-RFLP位点上,五指山猪以AA基因型为主;在MyoD基因第1内含子的DdeⅠ-RFLP位点上,等位基因A在五指山猪中是优势等位基因.此外,Myf5和MyoD基因启动子区域和第1外显子处存在CpG岛.本研究得到海南五指山猪Myf5和MyoD基因的序列信息,为下一步五指山猪Myf5和MyoD基因的功能研究奠定基础.     

荷斯坦牛免疫抗病相关Nramp1基因生物信息学分析

为研究牛的抗病能力,探究荷斯坦牛Nramp1基因所编码蛋白的结构与功能,本研究采用生物信息学分析的方法对荷斯坦牛Nramp1基因编码蛋白质的理化性质、疏水性/亲水性、信号肽跨膜区、跨膜结构域、N-糖基化位点和磷酸化位点、蛋白质二级结构、三级结构及蛋白质互作进行分析和预测.结果表明,荷斯坦牛Nramp1基因所编码蛋白全长...     

A preliminary study of possible genetic influences on the susceptibility of sheep to Johne's disease

OBJECTIVE: To investigate possible genetic influences on susceptibility or resistance of sheep to Johne's disease. DESIGN: A field and laboratory study of two fine-wool Merino flocks with a high prevalence of disease due to Mycobacterium avium subsp paratuberculosis infection. PROCEDURE: Adult sheep were phenotypically classified as having severe, mild or no disease on the basis of clinical, pathological and cultural tests for paratuberculosis, and as positive or negative in tests for humoral immunity (agar gel immunodiffusion test) or cell mediated immunity (skin test for delayed type hypersensitivity). Correlations with phenotype were sought for polymorphisms at loci within selected immune function genes (NRAMP, MHC complex, IFN-gamma, lysozyme, leukaemia inhibiting factor). RESULTS: Possible associations of particular NRAMP and MHC alleles with susceptibility or resistance to Johne's disease were detected. CONCLUSION: If the results of this preliminary study are confirmed in further work, then the use of rams with "resistant" genotypes may assist in the control of Johne's disease in infected flocks.