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.     

我国西藏四种植物染色体数目观察

本文对西藏四种植物进行染色体观察，这四种植物的染色体数目均为国内外首次报道。     

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.     

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.     

一种简易的花房温湿度无线自动监控系统

花房内的温湿度变化直接影响到花卉的健壮生长,以C8051F330为核心设计一款简易的花房温湿度无线自动监控系统,可对花房内的温湿度进行实时自动监控,当花房内温湿度指标超过设定值时,系统发出声光报警。该系统温度测量范围为-55~125℃,精度为±4℃;相对湿度测量范围为10%~90%,精度为±5%。经测试,系统运行稳定,...     

可燃气体检测与报警装置设计

文章介绍了以STC12C5201AD为核心的可燃气体检测与报警装置设计.该装置用催化型可燃气体传感器将气体浓度转换为对应的电压值,然后采用A/D进行采集和标度变换,最后由单片机进行信息处理,判断浓度是否超标,并控制报警动作.     

3％高渗苯氧威防治春尺蠖试验

利用2000倍液、3000倍液、4000倍液3个不同体积分数的3％高渗苯氧威进行了室内、室外防治春尺蠖幼虫试验，结果表明：施药72h后，室内试验的3个体积分数平均死亡率均达到100．0％；室外试验以2000倍液和3000倍液死亡率为最高，达到98．5％，防治效果显著。3％高渗苯氧威是理想的防治春尺蠖的仿生物杀虫剂。     

3S技术在林业资源调查上的应用研究

全球定位系统(GPS)、地理信息系统(GIS)以及遥感技术(RS)合称为3S技术,已在各个领域得到广泛应用。本文从实践角度对3S技术在林业资源调查上的应用进行了分析和探讨。