芦花鸡PRKAG3基因单核苷酸多态性及与肉质性状的相关性分析

为研究芦花鸡PRKAG3基因的多态性及与肉质性状相关性,采用PCR-SSCP方法检测PRKAG3基因外显子11的遗传多态性。结果检测到TT、TG和GG三种基因型,测序结果证实在2832位点存在T→G突变,为有意突变,统计分析表明,此多态位点与芦花鸡呈显著相关,pH值为GG基因型极显著低于TG基因型和TT基因型(P<0.01),而TG基因型显著低于TT基因型(P<0.05);其它肉质性状在不同基因型间差异不显著。此结果提示,PRKAG3基因对芦花鸡pH值具有较大的遗传效应,可以初步推断PRKAG3是控制这一性状的众多基因之一,可能是影响芦花鸡pH值的一个主效基因或与主效基因相连锁,可作为选育芦花鸡pH值的分子标记,用于标记辅助选择意义重大。     

猪Toll样受体3、7和8基因的克隆与序列分析

为了对猪Toll样受体(TLR)3、7和8基因进行克隆与序列分析,本实验从猪肺泡巨噬细胞(PAM)中,利用RT-PCR方法分片段扩增猪TLR3、7、8基因,并克隆于pMD18-T载体中。根据测序结果分析,猪TLR3、7和8基因的ORF分别为2718bp、3153bp和3087bp,并分别编码906、1051和1029个氨基酸。同源性分析结果显示,它们与GenBank中登录的猪TLR的相应序列同源性达99%以上;与牛、马、羊和人的同源性较高,与鼠的同源性次之,与鸡的同源性最低,其蛋白分子结构预测表明猪TLR3、7、8均为跨膜蛋白。     

Bovine Cells Infected in Vivo with Theileria Annulata Express CD11b,the C3bi Complement Receptor

Forsyth, L.M.G., Jackson, L.A., Wilkie, G., Sanderson, A., Brown, C.G.D. and Preston, P.M., 1997. Bovine cells infected in vivo with Theileria annulata express CD11b, the C3bi complement receptor. Veterinary Research Communications, 21 (4), 249-263Bovine cells from cattle infected with Theileria annulata were phenotyped with monoclonal antibodies recognizing bovine leukocyte antigens. Macroschizont-infected, transformed cell lines prepared from peripheral blood mononuclear cells of cattle, infected with sporozoites, were assessed by flow cytometry; parasitized cells in tissues from infected cattle were examined by immunocytochemical techniques. Co-expression of markers for different cell lineages by the cell lines precluded a definite conclusion as to their phenotypic origins. For, while the pattern of leukocyte antigens expressed by these in vivo-derived schizont-infected cells, which included CD11b, was indicative of a myeloid origin, the possibility that they were NK cells could not be excluded. The monoclonal antibody (MAb) IL-A15, which recognizes CD11b, reacted with a high proportion of parasitized cells in sections of tissues from infected cattle at all stages of acute disease. Mononuclear cells infected with parasites at all stages of differentiation, from macroschizont to microschizont, expressed CD11b. Such parasitized cells occurred throughout the lymphoid tissues, being found in the thymus, spleen and lymph nodes, particularly the prescapular node draining the site of infection, the hepatic, mesenteric and precrural nodes, as well as in the reticulo-endothelial tissue of the liver, kidney, lung, abomasum, adrenal and pituitary glands. These observations provided the first evidence for a myeloid origin for the parasitized T. annulata cells found in infected bovine tissues and blood and suggested a mechanism whereby schizonts could transfer from cell to cell during mechanical infection with schizont-infected cells.     

Bactrian camel (Camelus bactrianus) integrins αvβ3 and αvβ6 as FMDV receptors: Molecular cloning, sequence analysis and comparison with other species

Integrins are heterodimeric adhesion receptors that participate in a variety of cell–cell and cell–extracellular matrix protein interactions. Many integrins recognize RGD sequences displayed on extracellular matrix proteins and the exposed loops of viral capsid proteins. Four members of the αv integrin family of cellular receptors, αvβ3, αvβ6, αvβ1 and αvβ8, have been identified as receptors for foot-and-mouth disease virus (FMDV) in vitro, and integrins are believed to be the receptors used to target epithelial cells in the infected animals. To analyse the roles of the αv integrins from a susceptible species as viral receptors, we have cloned Bactrian camel αv, β3 and β6 integrin cDNAs and compared them to those of other species. The coding sequences for Bactrian camel integrin αv, β3 and β6 were found to be 3165, 2289 and 2367 nucleotides in length, encoding 1054, 762 and 788 amino acids, respectively. The Bactrian camel αv, β3 and β6 subunits share many structural features with homologues of other species, including the ligand binding domain and cysteine-rich region. Phylogenetic trees and similarity analyses showed the close relationships of integrin genes from Bactrian camels, pigs and cattle, which are each susceptible to FMDV infection, that were distinct from the orders Rodentia, Primates, Perissodactyla, Carnivora, Galliformes and Xenopus. We postulate that host tropism of FMDV may in part be related to the divergence in integrin subunits among different species.     

Feeding Solanum glaucophyllum to preparturient multiparous cows prevents postparturient hypocalcemia

Solanum glaucophyllum (SG) contains 1,25‐dihydroxyvitamin D₃ (1,25‐(OH)₂D₃) glycosides. We investigated the effect of SG on hypocalcemia in cows. Serum levels of 1,25‐(OH)₂D₃, total calcium and phosphorus dose‐relatedly increased after feeding with SG, while serum magnesium and chloride levels fell (P < 0.05). We also performed an ethylenediaminetetraacetic acid (EDTA) infusion to induce artificial hypocalcemia. Cows that had been fed 4.0 mg/kg body weight of SG daily for 2 weeks had a higher serum concentration of total calcium at the end of EDTA infusion than those not fed SG (P < 0.05). In a field trial, multiparous cows were assigned to one of four groups: (1) no SG, (2) 1.3 g or (3) 2.6 g of SG daily from 14 days before the estimated calving day until 3 days after calving, or (4) a single feed of 35.75 g SG at 3 days before the estimated calving day. The concentrations of serum total calcium after the calving in each treatment group were (1) 7.4, (2) 7.9, (3) 8.0 and (4) 8.9 mg/dL and higher for (4) than for (1) (P < 0.05). The data suggests that feeding a high dose of SG before the calving may maintain higher concentrations of serum calcium after the calving.     

马蹄金与匍茎翦股颖光合生理生态的比较研究

研究表明，１．通过光饱和点、光补偿点、ＣＯ＿２补偿点及叶绿素ａ／ｂ比值等测定，马蹄金与匍茎剪股颖均属喜光、耐荫的Ｃ＿３植物。马蹄金对强光适应性大于匍茎翦股颖。因而在芜湖地区作为大田草坪种植，则马蹄金优于匍茎葛股颖。２．ＮａＨＳＯ＿３均有增强光合速率、加速光合产物输出、增加于物质积累及提高生物产量的效应。光呼吸抑制剂在草坪生产上大有可为。     

探地雷达树木根系定位与直径估算

针对树木根系的探地雷达(Ground Penetrating Radar,GPR)检测图像复杂、解译困难、自动化程度低且精度不高等问题,该研究提出了一种基于YOLOv3的树根自动识别和参数估计的方法.通过不同的根预埋试验分析了根直径、掩埋深度和朝向对根系识别和预测的影响,对比评估了在复杂现场环境下该方法与商业软件常用的...     

采用改进YoloV4模型检测复杂环境下马铃薯

为解决马铃薯联合收获机在作业过程中分级清选的问题,并在收获作业过程中实时监测评估收获状态,该研究提出一种在光照亮度变化大、土壤与薯块遮挡、机器振动以及尘土干扰等情况下对马玲薯进行识别检测并快速准确获取马铃薯数量以及损伤情况的机器学习模型。在卷积神经残差网络中引入轻量级注意力机制,改进YoloV4检测网络,并将YoloV4结构中的CSP-Darknet53网络替换为MobilenetV3网络,完成特征提取。试验结果表明,基于卷积神经网络的深度学习方法相比于传统Open-CV识别提高了马铃薯识别精度,相比于其他传统机器学习模型,MobilenetV3-YoloV4识别速度更快,马铃薯识别的全类平均准确率达到91.4%,在嵌入式设备上的传输速度为23.01帧/s,模型鲁棒性强,能够在各种环境下完成对正常马铃薯和机械损伤马铃薯的目标检测,可为马铃薯联合收获机智能清选以及智能收获提供技术支撑。     

基于乌金猪深度发掘的优质高效新品种选育

目的揭示宣和猪PRKAG3基因外显子5多态性及其与肉质性状的关联。方法采用PCR产物直接测序法检测了120头宣和猪PRKAG3基因外显子5区域的SNP位点,借助最小二乘模型分析了各位点不同基因型及合并基因型对6个肉质性状的影响。结果宣和猪PRKAG3基因外显子5区域检出3个SNP位点,包括2个同义突变位点(T579C、T580C)和1个错义突变位点(G595A),分别以TT、TT、GA基因型和T、T、G等位基因的频率最高,且都处于Hardy-Weinberg平衡状态。T579C、T580C位点的TT和TC基因型可显著提高大理石纹(P<0.05)和降低失水率(P<0.01),分别呈显著的加性效应及加性—显性效应(P<0.05或P<0.01);G595A位点的AA基因型失水率最低(P<0.05)、熟肉率最高(P<0.05),呈显著的加性效应(P<0.05);3个位点的合并基因型TTTTGG、TCTCGG和TTTTAA分别具有最高的大理石纹、pH₁和最低的失水率(P<0.05或P<0.01),CCCCGG基因型的大理石纹和pH₁最低、失水率最高(P<0.05或P<0.01)。结论研究结果进一步确认宣和猪PRKAG3基因外显子5多态性与肌肉大理石纹、pH值和失水率显著关联,T579C、T580C位点的CC基因型和G595A位点的GG基因型具有协同降低猪肉品质的效应。     

三维CAD技术在机械设计中的应用

现代计算机在技术和性能上越发成熟,再加之网络的普及和信息的智能化处理技术的提高,三维CAD技术本身也正逐步成熟,因此,正确地把握CAD技术的发展趋势对我国机械工程中的设计工作具有深远的意义.