【摘要】 乳房炎是奶牛生产中最普遍、最复杂也是花费最多的疾病,而乳铁蛋白在机体抵抗乳房炎方面起着重要作用。从523头泌乳奶牛中,以临床乳房炎发病记录为基础,分别筛选出40头具有最高抗性和最高易感性的奶牛作为试验I组和试验II组。同时对bLF启动子和第4、15外显子做PCR-SSCP分析,在6个亚片断上,发现P1,P4,E4,E15等4个DNA片断存在多态,测序后发现6个突变位点。对4个DNA多态片断做进一步的分析,发现P1、P4片断的等位基因在试验两组中的分布呈显著差异,分别为53.7%vs 70.0%(P<0.05),55.0%vs68.8%(P<0.05),可作为潜在的分子标记。结合试验奶牛的生产记录分析了分子标记的相关影响,结果发现筛选将引起奶牛乳脂率显著上升(P<0.05),体细胞数显著下降(P<0.05),CMR值极显著差异(P<0.01)和产奶量显著下降(P<0.05)。同时还利用M atInspector7.2.2软件对突变引起的启动子区潜在转录因子结合位点的改变进行了研究,并预测了乳铁蛋白表达调节的两个可能的信号转导通路即NF-κB炎症响应途径和核激素受体途径。更多还原

【Abstract】 Mastitis is the most frequent,complex and costly disease in dairy cattle.Lactoferrin is known to play an important role in resistance to bacterial infections.In this study,a total of 80 cows,including 40 mastitis resistant and 40 mastitis susceptible animals as group I and group II,were selected from a population of 523 cows on the basis of clinical mastitis occurrence.PCR-SSCP analysis on four fragments within 5′region and two fragments of Exons 4,15 revealed that for these six fragments,four fragments(P1,P4,E4 and E15) had polymorphisms which totally included six base mutations by sequencing,but only two fragments(P1 and P4) in all selected animals confirmed a significant difference in allele frequencies between resistant and susceptible groups,53.7% vs 70.0%(P<0.05),55.0% vs 68.8%(P<0.05).Further study on these two promising marker combined with the production traits of cows demonstrated that the selection will result in significantly higher in fat percent(P<0.05),significantly lower in SCS(P<0.05) and CMR(P<0.01),significantly lower in milk yield(P<0.05).The putative transcription factor binding sites in 5′region were also studied by using MatInspector7.2.2 software,and two signal pathways regulating the expression of bLF including the NF-κB pathway and nuclear hormone receptor pathway were predicted.更多还原