农业机械化能否改善农业劳动力错配

农业劳动力是农业资源中极为重要的组成部分,探究农业机械化对农业劳动力错配的影响,有利于更好地改善农业劳动力错配,促进农业经济发展。利用2003—2017年29个省市的面板数据,采用LSDV、固定效应模型和差分GMM计量方法,测算农业劳动力错配指数,分析农业劳动力错配程度的时空差异,探讨农业机械化对农业劳动力错配的影响及地域差异。结果表明：农业劳动力错配有明显的时空差异。在时间上,2003—2017年中国农业劳动力错配程度由0.63降为0.32,整体配置呈现越来越合理的状态,且2011年之后错配改善效果最为明显。在空间上,东部地区年均农业劳动力错配程度为0.73,中西部错配程度为0.33,严重错配地区主要集中于东部;农业机械化能显著改善农业劳动力错配,且农业机械化对农业劳动力错配的影响存在地域差异,表现为农业机械化主要改善东部地区的农业劳动力错配,对中西部地区的影响效果较小。此外,农业工资水平和农产品价格水平均能有效改善农业劳动力错配。因此,提出要因地制宜改善农业劳动力错配,提高农业机械化水平,充分推动农业劳动力向农业高效产业配置,保障农业就业人员基本工资,有效推动农产品生产交易的政策建议。     

羊痘病毒环介导等温扩增(LAMP)检测方法的建立

为建立羊痘病毒(CaPV)的环介导等温扩增(LAMP)检测方法,本研究根据GenBank中羊痘病毒的保守基因序列,设计出针对羊痘病毒的LAMP引物,利用LAMP Real Time Turbidimeter LA-320仪优化得到病毒核酸等温扩增最佳条件是62 ℃恒温反应60 min。在此条件下,病毒核酸的最低检测含量为3.1×10^-2 pg/μL,灵敏度比OIE推荐的PCR方法高10⁴倍。添加钙黄绿素(calcein)建立的目测法,还可实现对上述病原体检测结果肉眼观察。本研究获得的CaPV LAMP仪器法和目测法可特异性地扩增羊痘病毒属的山羊痘病毒、绵羊痘病毒及牛疙瘩皮肤病病毒核酸,具有反应快速、特异性强、灵敏度高、操作简便、设备要求低等特点。     

Lumpy skin disease outbreaks investigation in Egyptian cattle and buffaloes: Serological evidence and molecular characterization of genome termini

Lumpy skin disease (LSD) is an endemic highly infectious viral disease affecting cattle in Egypt. This study aimed to identify and characterize the LSD virus (LSDV) outbreaks in Egypt between 2016 and 2018 and to determine the role of Egyptian buffaloes in the epidemiology of LSD. A total of 44 skin biopsies (41 from cattle and 3 from buffaloes) and 31 blood samples from asymptomatic buffaloes in contact with clinically infected cattle were collected from 7 Egyptian governorates and tested by real-time (rt)-PCR. The positive samples were further isolated, and the isolates were analyzed by conventional PCR to amplify the LSDV001 and LSDV002 genes; three isolates were sequenced, and the phylogenetic tree was constructed. In addition, 198 serum samples (102 from cattle and 96 from contact buffaloes) were examined using ELISA. Out of 44 skin nodules analyzed by rt-PCR, 31 (70.45 %) were positive while, non of the buffalo samples were positive. Out of 31 positive rt-PCR samples, LSDV was isolated on CAM (n=19; 61.29%) and MDBK cell culture. The virus isolates were confirmed by conventional PCR where 1237 bp product size was successfully amplified. The phylogenetic analysis of LSDV002 gene revealed that three sequenced LSDV isolates were identical to each other and to LSDV isolates from different countries in Africa, Asia, and Europe with 99–100 % identity. ELISA analyses showed seroreactivity of LSDV in Egyptian cattle and buffaloes. In conclusion, the Egyptian water buffalo serves as an accidental non-adapted host for the disease and this point requires more deep investigation. In addition, the current vaccine strategy should be re-evaluated for more coverage and effectiveness.     

牛结节性皮肤病病毒感染MDBK细胞后转录组差异表达分析

旨在探索牛结节性皮肤病病毒（lumpy skin disease virus,LSDV）与宿主细胞的相互作用,采集了具有典型临床症状的牛皮肤病变组织,接种MDBK细胞进行病毒分离,采用透射电镜观察病变组织及病毒感染后的MDBK细胞,同时对感染后24 h的MDBK细胞进行转录组学分析,筛选差异表达基因并将其按功能分类,分析它们参与的细胞信号通路。结果显示,LSDV在电镜下呈椭圆形,病毒粒子大小约320 nm×260 nm。转录组分析发现,与未处理组相比,显著差异表达的基因共499个,其中,112个基因上调表达,387个基因下调表达。通过GO和KEGG分析得知,差异表达基因主要富集在从细胞表面传导信号至细胞核内部的MAPK信号通路,其中,参与天然免疫且涉及细胞凋亡的MAP3K1基因表达呈现显著下调,提示病毒感染会影响宿主细胞的迁移与凋亡等过程。显著变化基因包括HIF1A、RORA、LRRK2、AP3B1和ANO6等,分别涉及到调节血管内皮生长因子、炎症反应、细胞增殖分化以及信号转导等功能,除此之外,不饱和脂肪酸及胆汁分泌两个信号通路也发生了显著变化。本研究为进一步深入探究LSDV的致病机制奠定了基础。