甜菜坏死黄脉病毒(BNYVV)75kDa通读蛋白基因及其54kDa片段的克隆与表达

 以甜菜坏死黄脉病毒(BNYVV)内蒙分离物的总RNA为模板,通过反转录和PCR扩增获得75kDa通读蛋白基因54kDa片段的目的片段。     

Effect of dietary vitamin C and ammonia concentration on the cellular defense response of Macrobrachium nipponense

This study examined the effects of dietary vitamin C and ammonia concentration on the cellular defense response of Macrobrachium nipponese . The response of the cellular defense was determined by monitoring changes in reactive oxygen intermediates in hemocytes, superoxide dismutase activity, catalase activity, glutathione peroxidase activity, glutathione reductase and glutathione transferase activity in muscle. The results showed that prawns fed the basal diet had a significant increase in reactive oxygen intermediates in response to exposure to ammonia-N. When dietary vitamin C was added to the feed, there was a significant decrease in reactive oxygen intermediates in response to exposure to ammonia-N. Total superoxide dismutase and glutathione peroxidase activity of prawns fed the basal diet decreased as ammonia-N increased. This decrease in activity was significantly less pronounced in prawns that were fed the dietary vitamin C supplement. In prawns that were fed the dietary vitamin C supplement there was no significant variation in catalase reductase or gluxathione reductase activity in response to variations in ammonia-N concentration. The glutathione transference activity increased at a low concentration of ammonia-N in prawns that were fed the dietary vitamin C supplement, but there was no significant variation in the prawns fed the basal diet. Overall the results indicate that dietary vitamin C supplements enhance the capacity of M. nipponese to respond to elevations in ammonia-N. This response involved several biochemical reactions known to be involved in cellular defense.     

离心式压缩机喘振问题分析

当压缩机内气体的流量较低时,气体容易出现旋转脱离现象,导致压缩机不能正常工作,采取增加压缩机内部液体的流量,在出口处设置单向阀防止气体倒流等措施,可有效地防止喘振的发生,保证输气管道的正常运行.     

HUDACAPP— 一种工艺规程自动设计系统

本文介绍浦沅工程机械总厂准柔性制造系统(P-FMS)中加工箱体零件所用的一个工艺规程自动设计系统—HUDACAPP,阐述了系统的原理、结构和实现.给出了实例.本系统能按零件输入信息自动生成工艺过程,选择机床、夹具、刀具、量具、切削参数以及计算工时,并能与P-FMS的实时管理调度软件联接,提供所需的资料.     

康绿功臣植物源农药防治苹果李始叶螨试验

以1．1％苦参碱康绿功臣粉剂、25％三氯杀螨醇乳油及73％克螨特乳油为供试药剂，在喀什垦区对苹果李始叶螨进行了小区及示范防治试验，结果表明，康绿功臣防治李始叶螨田间药效较好，具有安全、高效稳定、持效期长等优点，可以取代25％三氯杀螨醇。     

豫麦10号高产栽培技术调查总结

通过对小麦新品种豫麦1O号的观察,认为该品种在上蔡县增产潜力较大。为充分发挥其增产优势,从整地播种,施肥浇水,中、后期管理等方面提出了措施和建议。