CXCR2基因多态性与奶牛体细胞评分的关联性

利用基因测序技术对CXCR2基因进行了多态性筛查,结果发现存在+612A→G、+684G→A、+777G→C、+855G→A、+858C→A和+861G→A等6个突变位点,其中+855为新发现的SNP。6个位点都处于连锁不平衡状态,+684与+861位点之间和+777与+858之间的相关程度高(r2分别为0.635和0.541)。基因效应模型分析表明:+855和+861位点不同基因型对奶牛体细胞评分的影响没有显著性差异(P0.05)。+612位点不同基因型对体细胞评分的影响具有显著性差异(P0.05),AA基因型个体的体细胞评分最低为4.19,乳房炎抗性最强。+777位点不同基因型对体细胞评分的影响差异性显著(P0.05),GG基因型个体体细胞评分最低为4.17,对乳房炎的抗性较强,说明该基因+612和+777SNPs可作为奶牛乳房炎抗性分子标记位点。     

Comparison of bovine IgG1, IgG2 and IgM for ability to promote killing of Mycoplasma bovis by bovine alveolar macrophages and neutrophils

The IgG1, IgG2 and IgM fractions were purified by chromatography from bovine antisera to Mycoplasma bovis. They were assayed for specific antibody and compared for ability to promote killing of M. bovis by bovine peripheral-blood neutrophils and alveolar macrophages. None of the Ig preparations killed the mycoplasma in the absence of the cells. The IgG1 and IgG2 preparations both promoted mycoplasma killing by the macrophages; IgM appeared to have no effect. The IgG2 preparation promoted killing by the neutrophils but neither the IgG1 or IgM fraction appeared effective.     

荷斯坦牛中性粒细胞β-防御素基因克隆及其原核表达质粒的构建

根据已发表的牛β-防御素基因序列设计引物,从具有临床乳腺炎症状的荷斯坦奶牛血液中性粒细胞中提取RNA,克隆牛β-防御素基因并插入到原核表达载体pQE-30中,构建了原核表达质粒pQE-30/β-defesion。测序结果表明,克隆的目的基因长189bp,编码1个氨基酸,与已报道的牛β-防御素氨基酸序列同源性达95.6%。本研究为牛乳腺防御素的表达及功能、活性的研究奠定了一定的基础。     

奶牛群体生长激素基因多态性与产奶量关联性

设计7对引物,利用PCR-SSCP技术检测GH基因在130头中国荷斯坦奶牛群体的遗传多态性,研究该基因对产奶量的影响。结果发现在GH基因的第3内含子、第5外显子和3′端存在多态性。GH基因第3内含子等位基因A、B的基因频率为0.775和0.225,3′端等位基C、D在奶牛群体中的基因频率为0.729和0.271,GH基因第5外显子等位基因E、F和G、H在奶牛群体中的基因频率分别为:0.507、0.138和0.259、0.096,GH基因第3内含子座位上不同基因型对305d产奶量有显著效应,AB基因型305d产奶量显著高于AA和BB型(P0.05)。     

水貂生长激素基因多态性与体质量性状的关联分析

以水貂的生长激素基因(GH)作为候选基因,采用单链构象多态性和DNA测序的方法检测GH基因单核苷酸多态性(SNPs),并针对该群体特点建立合适的统计分析模型,探讨GH基因多态性与体质量性状的相关性。结果表明,C→A突变产生的3种基因型间的水貂个体体质量存在一定的差异(P0.05),BB基因型个体与AA基因型个体之间有一定的差异(P0.05)。T→A和C→G突变没有导致氨基酸的变化,DD基因型个体体质量平均值要高于CC基因型,但产生的3种基因型对水貂体质量的影响没有显著性差异(P0.05)。统计各基因型之间的组合给水貂体质量带来的影响时,发现不同基因型之间的组合对所检测水貂样本的体质量有影响(P0.05)。     

Association of single nucleotide polymorphism of chicken uncoupling protein gene with muscle and fatness traits

Uncoupling proteins (UCPs) are in the mitochondrial inner membrane and belong to the transporter family. The biological function of UCPs is regulating discharge of proton gradient generated by the respiratory chain. As a result, the production of ATP is diminished, and dissipative heat is yielded. The present study was designed to investigate the association of UCP gene with chicken growth and body composition traits. The ninth generation of the broiler lines divergently selected for abdominal fat was used as a research population. Primers for UCP gene were designed from chicken genomic sequence. A single-nucleotide polymorphism, in the exon3 (T1316C) of UCP gene was detected by the polymerase chain reaction and restriction fragment polymorphism (PCR-RFLP) method. The UCP polymorphism was associated with muscle and fatness traits, such as pectoralis minor weight and abdominal fat weight. The results indicated that UCP gene could be a candidate locus or linked to a major gene which affects muscle and fatness traits in chicken.     

澳系进口荷斯坦奶牛CXCR1基因遗传多态性与泌乳性状及体细胞评分的关联性分析

采用聚合酶链式反应-单链构象多态性（PCR—SSCP）技术对以海丰奶牛场588头澳系进口荷斯坦牛牛趋化因子受体1（Chemokine receptor1,CXCR1）基因的遗传多态性进行分析;采用混合动物模型分析CXCRl基因2个突变位点与测定日产奶量、乳脂率、乳蛋白率、305d产奶量、305d乳脂量、305d乳蛋白量及体细胞评分7个性状的相关性,寻找可用于生产实际的分子标记。结果显示,CXCR1基因5’侧翼区-1830位点发生了A—G的突变,检测到AA、AG和GG3种基因型,频率分别为0．684、0．289和0．027,等位基因A和G的频率分别为0．828和0．172;GG基因型奶牛的日产奶量、SCS和305d产奶量均板显著高于AA基因型（P〈0．01）,而其乳脂率和乳蛋白率却显著低于AA基因型奶牛（P〈0．05）。编码区783位点仅发现AA和AC2种基因型,基因型频率分别为0．886和0．114,等住基因A和c的频率分别为0．943和0．057。AA型的个体的日产奶量、305d脂肪产量和305d蛋白产量极显著高于AC型个体,而其乳脂率、乳蛋白率和SCS却极显著低于AC型个体（P〈O．01）。结果表明,CXCR1基因遗传突变对澳系进口荷斯坦牛泌乳性状和乳房炎抗性有较大的遗传效应,可用于澳系进口荷斯坦牛的分子标记辅助选择。     

澳系进口荷斯坦奶牛CXCR1基因遗传多态性与泌乳性状及体细胞评分的关联性分析

采用聚合酶链式反应-单链构象多态性(PCR-SSCP)技术对以海丰奶牛场588头澳系进口荷斯坦牛牛趋化因子受体1(Chemokine receptor 1,CXCR1)基因的遗传多态性进行分析;采用混合动物模型分析CXCR1基因2个突变位点与测定日产奶量、乳脂率、乳蛋白率、305d产奶量、305d乳脂量、305d乳蛋白量及体细胞评分7个性状的相关性,寻找可用于生产实际的分子标记。结果显示,CXCR1基因5′侧翼区-1830位点发生了A→G的突变,检测到AA、AG和GG 3种基因型,频率分别为0.684、0.289和0.027,等位基因A和G的频率分别为0.828和0.172;GG基因型奶牛的日产奶量、SCS和305d产奶量均极显著高于AA基因型(P<0.01),而其乳脂率和乳蛋白率却显著低于AA基因型奶牛(P<0.05)。编码区783位点仅发现AA和AC 2种基因型,基因型频率分别为0.886和0.114,等位基因A和C的频率分别为0.943和0.057。AA型的个体的日产奶量、305d脂肪产量和305d蛋白产量极显著高于AC型个体,而其乳脂率、乳蛋白率和SCS却极显著低于AC型个体(P<0.01)。结果表明,CXCR1基因遗传突变对澳系进口荷斯坦牛泌乳性状和乳房炎抗性有较大的遗传效应,可用于澳系进口荷斯坦牛的分子标记辅助选择。     

奶牛乳腺乳脂肪形成相关基因的遗传多态性

牛奶营养品质低下已成为我国奶业健康发展所面临的严峻挑战。乳脂肪是决定牛奶营养品质的主要物质之一。调控乳腺内脂肪酸转运、从头合成、酯化和脂滴形成的相关基因的遗传多态性对乳脂肪的成分及含量具有重要影响。本文综述了这些基因的遗传多态性及其对乳脂肪生成的影响,旨在为明确奶牛乳腺脂肪酸形成调控网络提供理论基础和研究思路。     

Genetic polymorphism of bovine beta-casein gene in Japanese dairy farm herds

The aim of this study was to investigate beta-casein polymorphism among 320 Japanese cows sampled from eight dairy farms. We used a newly-developed genotyping method that involved collecting DNA from hairs and a Cycleave polymerase chain reaction (PCR) assay to detect the A1, A2, and B variants. Results revealed the presence of five genotypes (A1A1, A2A2, A1A2, A1B, and A2B). We found that the most common genotype was A2A2 (0.42), followed by A1A2 (0.39) and A1A1 (0.11). The A1B and A2B genotypes were less frequent (<0.05). The frequencies of alleles A1, A2, and B were calculated to be 0.32, 0.64, and 0.04, respectively. Our study is the first to show the current status of beta-casein polymorphisms in Japanese dairy farms. Given the adverse effects of A1 beta-casein on human health, attempts have been made to develop herds consisting solely of A2A2 cows. Our study provides a reference for improving cow populations in Japanese dairy farms. The Cycleave PCR-based assay we developed here can be used for rapid and reliable genotyping of bovine beta-casein.     

Association of a single nucleotide polymorphism in the calpastatin gene with carcass and meat quality traits of beef cattle

Calpastatin (CAST) is a naturally occurring protein that inhibits the normal tenderization of meat as it ages postmortem. A SNP was identified in the CAST gene (a G to C substitution) and genotyped on crossbred commercially fed heifers (n = 163), steers (n = 226), and bulls (n = 61) from beef feedlots, and steers (n = 178) from a University of Guelph feeding trial. The association of the CAST SNP with carcass and meat quality traits was studied. Carcass traits included fat, lean, and bone yield; grade fat; LM area; and HCW. Meat quality traits included marbling grade; i.m. fat content of LM; tenderness evaluation of LM (Warner-Bratzler shear force) at 2, 7, 14, and 21 d of postmortem aging; and tenderness evaluation of semitendinosus muscle at 7 d of postmortem aging. The mixed model used in the analyses included fixed effects of CAST genotype, sex, slaughter group, and breed composition (linear covariate); sire was a random effect. For the analysis of shear force, i.m. fat content of LM was also included in the model as a linear covariate. Shear force measures were analyzed within days of postmortem aging and by repeated measures analysis. The CAST SNP allele C was more frequent (63%) in the crossbred population than allele G. The CAST SNP was associated with shear force across days of postmortem aging (P = 0.005); genotype CC yielded beef that was more tender than GG (-0.32 kg +/- 0.13), and CG had intermediate tenderness. The corresponding average allele substitution effect (G to C substitution) was also highly significant (-0.15 +/- 0.05 kg, P = 0.002). A lower percentage of unacceptably tough steaks (shear force > 5.7 kg) at 2 and 7 d postmortem was associated with an increasing number of C alleles (P < or = 0.05). At 7 d postmortem, the percentage of unacceptably tough steaks decreased by 24 and 35%, respectively, for animals carrying 1 and 2 copies of the C allele relative to animals with no C alleles. However, genotype CC had a greater fat yield (+1.44 +/- 0.56%; P = 0.037) than genotype GG, with a corresponding allele substitution effect of 0.67 +/- 0.27% (P = 0.015). Therefore, the CAST SNP allele C was associated with increased LM tenderness across days of postmortem aging and, importantly for the beef industry, had a significant reduction in the percentage of steaks rated unacceptably tough by consumers based on an assumed threshold level.     

DNA polymorphism in the chicken growth hormone gene: Association with egg production

Restriction fragment length polymorphic markers in the chicken growth hormone (GH) gene were tested for their association with egg production traits. Alleles of GH were determined in 3 non‐inbred strains from different genetic bases. The frequency of PS1 (+) allele in the three strains was very low in contrast to the layer strain previously reported. Results of the present study indicate that the frequency of PS (+) is related to egg production and that the PS1 (+) allele may be used as a genetic marker for selection in egg production.     

松辽黑猪L-FABP基因外显子2多态性及与肉质性状的相关性分析

以松辽黑猪为研究对象,采用PCR-SSCP方法检测了肝脏脂肪酸结合蛋白(L-FABP)基因外显子2的多态性,并将不同基因型与肉质性状进行相关性分析.结果表明,在外显子2发现多态性位点,有AA、AT和TT三种基因型;测序发现在1760 bp处存在T→A的碱基突变.并导致了苯丙氨酸变为亮氨酸;该位点的多态性对松辽黑猪的大理石纹和IMF含量均有显著影响(P<0.05),大理石纹为AA型显著高于TT型(P<0.05),AT型与AA型,AT型与TT型之间差异均不显著(P>0.05);IMF含量为AA型和AT型显著高于TT型(P<0.05),AA型和AT型之间差异不显著(P>0.05);其他内质性状的不同基因型之间差异不显著(P>0.05).因此推断L-FABP基因可能是影响猪肉质性状的主效基因或是与影响肉质性状的QTL连锁的基因.     

Prion protein gene polymorphism and blood lymphocyte profile in cows naturally infected with bovine leukemia virus

The polymorphic loci of the bovine prion protein (PRNP) gene, comprising 23-bp insertion/deletion (23-bp indel) within the promoter sequence and 12-bp insertion/deletion (12-bp indel) within the intron 1 sequence, are located in regions which play a key role in gene expression. The objective of this study was to determine whether the 23-bp and 12-bp insertion/deletion polymorphism within the PRNP gene leads to significant differences in the blood lymphocyte profile and to investigate changes in the composition of these cells in cattle naturally infected with Bovine Leukemia Virus. An analysis of the effect of the bovine PRNP gene polymorphism on the blood lymphocyte profile revealed considerable differences between animals with the 23-bp indel genotypes, and small and statistically non-significant differences between those with the 12-bp indel genotypes. 23-bp del/del homozygotes had a significantly lower percentage of T lymphocytes with the phenotypes CD2 (P < 0.01), CD8 (P < 0.01) and WC1-N2 (P < 0.05), and a higher ratio of CD4 to CD8 T lymphocytes, compared to animals with the 23-bp ins/ins genotype. The obtained results indicate that the 23-bp indel polymorphism, in contrast to the 12-bp indel polymorphism, has a significant effect on changes in the blood lymphocyte profile. The size of blood lymphocyte subpopulations was also found to change under the influence of enzootic bovine leukosis. The direction of those changes in EBL-positive animals is consistent with that observed in 23-bp del/del homozygotes, which may testify to the adverse effect of this genotype on immunological efficiency.     

Association of a single nucleotide polymorphism in ribosomal protein L27a gene with marbling in Japanese Black beef cattle

Marbling, defined by the amount and distribution of intramuscular fat, is an economically important trait of beef cattle in Japan. The c2‐11#2 expressed sequence tag (EST) has been previously shown to possess expression difference in musculus longissimus muscle between low‐marbled and high‐marbled steer groups, and to be located within genomic region of a quantitative trait locus for marbling. Thus, the ribosomal protein L27a (RPL27A) gene containing the c2‐11#2 EST sequence was considered as a positional candidate for the gene responsible for marbling. In the present study, a single nucleotide polymorphism (SNP) in the promoter region of the RPL27A, referred to as g.3109537C>T, was detected between the 2 steer groups. The SNP was associated with the predicted breeding value for beef marbling standard number by the analyses using Japanese Black beef cattle population. The effect of genotypes of the SNP on the predicted breeding value for subcutaneous fat thickness was not statistically significant. These findings suggest that the RPL27A SNP may be useful for effective marker‐assisted selection to increase the levels of marbling in Japanese Black beef cattle.     

中国荷斯坦牛CXCR1基因第二外显子新SNPs与乳腺炎的关联分析

通过研究中国荷斯坦牛趋化因子受体1(Chemokine(C-X-C motif)receptor1,CXCR1)基因多态性与乳腺炎间的相关性,找到对乳腺炎性状有显著影响的基因型和单倍型组合,为从遗传角度上解决奶牛乳腺炎问题提供参考。采用巢氏PCR、DNA测序和CRS-PCR-RFLP方法,对中国荷斯坦牛的CXCR1外显子2进行遗传多态性研究,分别利用SHEsis软件和PHASE软件进行配对连锁不平衡分析和单倍型分析。结果表明,找到了4个新SNPs,分别为291(C/T)、333(C/T)、337(A/G)和365(C/T)。各SNPs与中国荷斯坦牛体细胞评分(SCS)和产奶量的关联分析表明:337(A/G)和365(C/T)位点的等位基因G、C均为低SCS、高产奶量的优秀等位基因;另外,H3 H7(CCCTGGCC)单倍型杂合个体为低SCS、高产奶量的优秀单倍型组合。CXCR1基因的单倍型H3 H7(CCCTGGCC)在SCS和产奶量方面是优良的单倍型,可作为选择抗乳腺炎的分子标记。     

Prevalence of coagulase gene polymorphism in Staphylococcus aureus isolates causing bovine mastitis.

This study was conducted to investigate polymorphism of the coagulase gene of Staphylococcus aureus causing bovine mastitis. One hundred eighty-seven strains of S. aureus were isolated from bovine mastitic milk samples obtained from 187 different Danish dairy farms. The isolates were characterised for restriction fragment length polymorphism (RFLP) of the coagulase gene. A variable region of the coagulase gene was amplified using the polymerase chain reaction (PCR) followed by AluI restriction enzyme digestion. A total of 15 different RFLP patterns were observed. The predominant pattern was found in 35% of the isolates. The ease of analysing coagulase gene polymorphisms among a large number of strains, and the multiple distinct polymorphic patterns generated, supports the use of this technique in epidemiological investigations of bovine mastitis. The predominating variants may have predelection for causing intramammary infections.     

Phylogenetic relationships of Staphylococcus aureus from bovine mastitis based on coagulase gene polymorphism

Coagulase gene restriction fragment length polymorphism (RFLP) patterns were analyzed to determine the phylogenetic relationship among isolates of Staphylococcus aureus from the Czech Republic (n = 27), France (n = 48), Korea (n = 115) and the United States (n = 278). A total of 468 isolates of S. aureus were subtyped into 41 coagulase genotypes. Cluster analysis placed the 41 types into nine clusters. Eighteen API Staph profiles were determined for 102 S. aureus isolates representing 1 to 4 isolates of each coagulase type. The results of the study suggest that based on coagulase gene RFLP analysis, several genetic variants of S. aureus are prevalent. Comparison of coagulase and API Staph profiles indicated that the two identification system were independent of each other.