奶牛乳腺炎防治的免疫学和药理学机制

奶牛乳腺炎是一种复杂的多因素疾病，给世界各国奶牛业造成了巨大的经济损失，而至今未能提出一个彻底解决的办法。本文综述了奶牛乳腺炎的致病因素、乳腺的免疫机制和乳腺炎治疗的药理学机制方面的研究进展，重点剖析了乳腺特殊的免疫体系和乳腺炎治疗的药理学特点，分析阐明了奶牛乳腺炎免疫和治疗失败的原因。     

The Application of GIS in Small Watershed Classification in Loess Plateau

ＴｈｅＡｐｐｌｉｃａｔｉｏｎｏｆＧＩｓｉｎＳｍａｌｌＷａｔｅｒｓｈｅｄＣｌａｓｓｉｆｉｃａｔｉｏｎｉｎＬｏｅｓｓＰｌａｔｅａｕＺｈｕＪｉｎｚｈａｏ，ＷｕＢｉｎ，ＢｉＨｕａｘｉｎｇ，ＺｈｏｕＣｈａｎｇｑｉｎｇＣｏｌｌｅｇｅｏｆＳｏｉｌａｎｄＷａｔｅｒＣ...     

建设横县花茶名县的战略思考(一)

横县位于广西东南部,属南亚热带季风气候,面积3464平方公里,四周多山,整个地形似盆地.辖5乡17镇,人口106万;耕地面积7.67万公项(115万亩),粮食作物以水稻为主.主要经济作物有:茉莉花、糖蔗、黑皮果蔗、荔枝、龙眼、蜜梨、茶叶、蚕桑、大头菜、香芋等.     

图书馆工作人员应该转变的六个观念

文章认为，要使图书馆工作适应新的技术革命和社会主义市场经济的需要，就必须转变观念。当前需要转变的观念有以下六个方面:图书馆由藏书中心变成文献资料中心、信息中心、智力开发中心;从关门办馆到开门办馆:从无偿服务到有偿服务:从独自办馆到馆际协作:从手工操作到运用现代技术手段:从与世无争到积极竞争。     

近冰点温度贮藏草莓的研究

草莓呼吸旺盛,果皮薄易受伤,难以贮藏。利用近冰点温度贮藏可以明显地抑制草莓的呼吸作用,结合小袋包装的气密性,改善了包装内部的气体组成,提高草莓果实周围的相对湿度并减少空气对流,从而抑制了草莓在贮藏过程中糖分、水分的损耗,减少了糖酸比值的下降。保持了一定的感观指标,可使草莓的贮藏时间延长。     

靠接换砧矫治枳砧甜橙缺铁黄化研究

靠接红桔、酸桔和枸头橙砧,矫治枳砧甜橙缺铁黄化有明显效果。其中,以枸头橙效果最好,以下依次为酸桔和红桔,靠接砧苗后树势逐年恢复,产量成倍增加,靠接红桔、酸桔和枸头橙分别比对照增产3.3、1.4和1.5倍;对提高果实含糖量、果汁率和降低含酸量亦有良好效果。     

Porcine reproductive and respiratory syndrome virus: morphological, biochemical and serological characteristics of Quebec isolates associated with acute and chronic outbreaks of porcine reproductive and respiratory syndrome.

Cytolytic and noncytolytic strains of the porcine reproductive and respiratory syndrome virus (PRRSV) were isolated in primary cultures of porcine alveolar macrophages (PAM) from lung homogenates of stillborn fetuses or blood samples of dyspneic piglets collected from Quebec pig farms having experienced acute or chronic outbreaks of PRRS. Serological identification of the virus was confirmed by indirect immunofluorescence and indirect protein A-gold immunoelectron microscopy using reference antiserum prepared from experimentally-infected specific pathogen free (SPF) piglets and monoclonal antibodies (MoAbs) directed against the p15 nucleocapsid (N) protein of the reference ATCC-VR2332 isolate. Intracytoplasmic enveloped viral particles that tended to accumulate into cytoplasmic vesicles were observed in the infected PAM; no budding was demonstrated at the level of the cytoplasmic membrane. The extracellular virions appeared as pleomorphic but mostly spherical enveloped particles, 50-72 nm in diameter (averaged diameter of 50 particles was 58.3 nm), with an isometric core about 25-30 nm. Buoyant density of the virus in CsCL density gradients was estimated to 1.18-1.20 g/mL. No hemagglutinating activity was demonstrated. Analysis of semipurified virions of isolate IAF-exp91 by radioimmunoprecipitation (RIPA) and Western immunoblotting experiments, using reference rabbit and porcine hyperimmune sera, revealed four major viral proteins, a predominant 15 kD N protein and three other proteins with predicted M(r_ of 19, 26 and 42 kD. Progeny viral particles produced in PRRSV-infected PAM in the presence of tunicamycin lacked the 42 kD protein, thus confirming its N-glycosylated nature. Immunoprecipitation experiments using the anti-ATCC-VR2332 MoAbs confirmed the close antigenic relationships between Quebec and American reference isolates of PRRSV.     

原发性纵隔肿瘤及囊肿71例分析(附1例罕见胸腺瘤并发症)

71例原发于纵隔的肿瘤及囊肿,其中胸腺瘤占35.2％,畸胎瘤占23.9％,神经源性肿瘤占18.2％,其他肿瘤占22.7％。三类常见肿瘤中,以胸腺瘤恶性率最高(32％),神经源性肿瘤次之(15.4％),畸胎瘤无1例恶性。术前正确诊断25例,未能分类25例,误诊21例。本文分析了误诊原因。此外,报道1例罕见的胸腺瘤并发症。     

湖羊生长性状遗传参数的估测

对湖羊生长性状的表型参数和遗传参数的估测表明，性别对这些生长性状有极显著的影响，在遗传参数的估测中剔除性别的效应可提高估计的正确性。初生重、断奶重、三月龄重、六月龄重、周岁重和日增重等性状都属于高遗传力性状，遗传力分别为０．４１９０，０．３０４２．０．６０２３，０．６０７７，０．３９５６和０．６９４５．根据相关分析结果，为提高湖羊的生长速度和肉用性能，把日增重和三月龄重作为主要选择性状，预期可获得较好的效果     

Fusarium oxysporum对苗期大豆根部的致病性和侵染规律

Fusarium oxysporum对苗期大豆具有较强的致病作用。病原菌自伤口或直接侵入大豆幼苗根部的皮层组织,随着病原菌的侵入和扩展,细胞出现坏死,组织发生崩解,根部组织表现红褐色病斑。环境因素对病原菌的侵染时期和在大豆体内潜育时间的长短有着明显的影响。侵染时期主要受病原菌侵入前自身所处状态和寄主的影响,侵入后潜育时间的长短则受植株状态的影响。土壤环境条件直接影响着病原菌的侵入和寄主的抗病性,间接影响着病原菌在大豆植株体内的扩展和病症的表现。