线虫fat-1基因密码子优化设计

本研究旨在优化线虫fat-1基因,使其在牛肌肉组织中高效表达,为进一步生产fat-1转基因肉牛提供目的基因。试验在不改变fat-1基因编码氨基酸序列的基础上,参考了11个牛肌肉蛋白相关基因的密码子使用频率,对fat-1基因进行了密码子优化。结果发现,共改变了65个碱基,涉及65个密码子、7个氨基酸,约占fat-1基因总碱基数的5.38%,G+C含量从45.08%上升到50.04%,且分布均匀利于基因的表达。结构预测结果显示,该优化后的基因能够在牛肌肉中高效表达。     

The Effects of Forced Exercise on Collagen Type II Fragments,Lysyl Oxidase Concentrations,and Total Protein Concentrations in Sera and Synovial Fluid of Lambs

Excessive exercise may induce osteoarthritis, which is a leading cause of lameness and decreased use in horses. The purpose of this study was to utilize a sheep model to determine the effects of circular and linear exercise on biochemical markers in serum and synovial fluid (SF). Twenty lambs (5 months) were assigned to three groups: circular exercise (C, 8.5 m diameter; n = 8), straight-line exercise (S, treadmill; n = 8) and nonexercised control (CON, n = 4). Lambs (C and S) were exercised up to 8 weeks at 1.3 m/s for up to 30 minutes, 6 days per week. Serum and SF from a metacarpophalangeal (MCP) joint was collected. Serum total protein (P = .66), Collagen Type II cleavage [3/4] fragments concentrations (P = .44) and lysyl oxidase (LOX) (P = .15) activity were not different among treatment groups throughout the study. There was a polynomial response to serum LOX over time (R² = 0.7464). There were no differences in SF total protein (P = .94, right MCP; P = .68, left MCP) or SF LOX specific activities (P = .9, right MCP; P = .93, left MCP) among groups throughout the study. However, SF LOX specific activity did increase over time (P = .001) for all treatment groups. These results indicated that the biochemical markers utilized in this study were unable to detect differences between groups with respect to exercise protocols. However, the LOX activity did increase over time possibly as a result of growth.     

悬液芯片系统在检测领域的研究进展

悬液芯片系统诞生于20世纪90年代中期,由美国Luminex公司的研制。该系统使用荧光编码的聚苯乙烯微球作为特异性反应的固相载体,通过偶联试剂的作用,将蛋白质、寡核苷酸、小分子肽类及脂肪偶联到微球的表面构成不同的检测探针。在反应体系中,检测探针通过特异性反应（如抗原―抗体,配体―受体,核酸互补碱基对）捕获与探针相对应的分析物,用荧光标记物标记与探针结合的分析物得到悬液芯片系统的检测物。依据微球内部红色和橙色荧光染料比例的不同,将供悬液芯片系统使用的聚苯乙烯微球分为100种不同的型号。检测器对荧光标记物荧光强度进行检测的同时能分辨不同型号的微球,并将不同型号微球对应的标记物的荧光强度进行分别记录,最终实现一次分析多种检测物的目的。作者综述了悬液芯片系统的原理及在蛋白质、核酸检测领域的研究进展。     

半胱胺对绒山羊瘤胃及盲肠内环境的影响

本试验选用4头6月龄、平均体重为16kg左右、安装永久性瘤胃瘘管和盲肠瘘管的辽宁绒山羊,平均分为半胱胺组和对照组,观察辽宁绒山羊瘤胃及盲肠内环境的变化。结果表明:半胱胺组瘤胃pH较对照组差异不显著(P0.05)。半胱胺组瘤胃NH3-N浓度、瘤胃蛋白浓度较对照组差异显著(P0.05);盲肠pH、蛋白浓度半胱胺组较对照组均差异不显著(P0.05)。本试验结果提示,添加半胱胺后可改变瘤胃内环境,有利于瘤胃微生物蛋白的合成。     

Evaluation of vegetable protein in canine diets: Assessment of performance and apparent ileal amino acid digestibility using a broiler model

Recent technological advances in the human food industry with respect to meat processing have decreased the availability of animal proteins to the pet food industry which typically formulates diets with an excess of animal protein. In the long term, this is not sustainable; thus, alternative protein sources need to be investigated. This study examined three canine diets, comparing a typical animal protein‐based diet (control) with two experimental diets where the animal protein was substituted in part with vegetable protein (formulated based either on total protein or amino acid content) using a broiler model. Each diet was fed to six cages each containing two birds from day 15, 18 cages in total (36 birds). Excreta were collected from days 19 to 21. On day 23, birds were euthanized and weighed, and their ileal digesta were collected and pooled for each cage. In addition, one leg per cage was collected for evaluation of muscle mass. Results showed no significant difference in animal performance (feed intake or live weight gain) or muscle to leg proportion across the diets. Birds fed the control diet and the diet balanced for amino acid content exhibited the greatest coefficients of apparent metabolizability for nitrogen (p < .001). Birds fed the diets that contained partial replacement of animal with vegetable protein generally had greater ileal digestibility of amino acids compared to birds fed the control (animal protein) diet. Analysis of excreta showed no dietary difference in terms of dry matter content; however, birds fed the diet balanced for total protein and the diet balanced for amino acid content had significantly greater excreta nitrogen than the control (p = .038). Overall, the study suggests vegetable proteins when formulated based on amino acid content are a viable alternative to animal proteins in canine diets.     

昆虫蛋白质饲料在动物生产中的应用

昆虫是最具开发潜力的动物性蛋白质饲料资源。作者就昆虫的营养价值、昆虫蛋白质饲料在畜牧业生产上的开发应用效果进行了综述,最后提出了昆虫饲料的发展前景。     

鸭肠炎病毒NP蛋白的原核表达及间接ELISA方法的建立

设计一对特异性引物扩增出鸭肠炎病毒(DEV)核衣壳蛋白(NP)基因,并将其定向插入到原核表达载体pET32a上,构建了NP基因的原核表达载体pET-NP;将重组载体pET-NP转化表达宿主菌BL21后,经SDS-PAGE分离后行Western blot显示,获得的表达产物具有良好的免疫原性;应用His.Bind亲和层析柱纯化重组NP蛋白,并以此作为包被抗原,初步建立了检测鸭肠炎病毒抗体的iNP-ELISA;经方阵滴定确定,重组蛋白抗原的最佳包被浓度为5.0μg/L,血清最佳稀释度为1∶80,阳性判定标准为:待检血清OD405值≥1.2,且待检血清OD405和阴性血清OD405的比值≥2.0;应用iNP-ELISA对450份鸭血清样本进行检测,结果iNP-ELISA与全病毒包被的iDEV-ELISA符合率达90.9%。     

牛杀菌／通透性增加蛋白氮端基因的克隆和序列分析

本试验应用RT-PCR技术,参照Genbank报道的序列,从荷斯坦牛中性粒细胞mRNA中扩增出杀菌／通透性增加蛋白（BPI）氮端基因（713bp）,并与pGEM-T-easy载体连接,构建基因重组体pGEM-T-easy-BPI,进行序列测定。结果表明获得长度为713bp的BPI氮端基因。序列分析证实该片段与安哥斯牛BPI氮端基因相比有1个点突变,为同义突变。该基因的克隆为进一步表达该基因奠定了基础。