大豆花叶病毒对大豆生长的影响

在人工接种江苏大豆花叶病毒（ＳＭＶ）ＳＡ株系条件下，研究了ＳＭＶ对１９个抗性不同的大豆品种９个主要性状的影响。结果表明，１３个感病品种在苗期接种ＳＡ后，除根瘤数外其余８个性状均与对照有极显著差异，受ＳＭＶ影响的程度从大至小依次为单株粒重、单株叶面积、根瘤重、茎叶干重、根干重、种子褐斑粒率、株高、百粒重。抗病品种９个性状均与对照无显著差异。感病品种在苗期与花期分别接种ＳＡ后，褐斑粒率、百粒重、单株粒重有极显著差异，早期感染ＳＭＶ其危害大于中后期感染．     

实验性鸡大肠杆菌病病理学动态变化

用致病性大肠杆菌O18分离株和／或低致病性禽流感病毒（Mildly pathogenic avian influenza virus ,MPAIV)接种10－12日龄SPF鸡。在接种后1－96h进行临床症状与大体病理变化、组织学观察发现：大肠杆菌接种组、MPAIV接种组和健康接种组除扑杀鸡外未见鸡死亡，MPAIV与大肠杆菌混合接种组除扑杀鸡外死亡率为24％。混合接种组的病变比大肠杆菌接种组出现的时间早，恢复也慢，各脏器的病理变化更严重。MPAIV主要引起各实质器官的坏死，结果表明，大肠杆菌经气管内接种后试验鸡主要表现为呼吸道的炎症反应；MPAVI可使鸡大肠杆菌病严重化。     

The lesional changes and pathogenesis in the kidney in african swine fever

African swine fever is a viral haemorrhagic disease of pigs which has been used as a model for the study of viral haemorrhagic diseases in man. The acute course of the disease is characterized by acute proliferative glomerulonephritis, with viral replication in mesangial cells and occasional focal necrosis of the renal tubular system; hyperplasia of the collecting ducts is associated with evident virus replication. Haemorrhages have been attributed to endothelial dysfunction, aggravated by virus replication in endothelial cells in the final stages of the disease. The renal interstitium displays intense oedema and an infiltrate largely composed of macrophages. Virus replication has also been observed in fibroblasts and in the smooth0muscle cells of arterioles and venules.In subacute-chronic forms of the disease, various types of glomerulonephritis are observed, ranging from mesangial proliferative glomerulonephritis to focal and segmental hyalinosis associated with immune-mediated phenomena. No striking changes are reported in the renal tubular system. Interstitial haemorrhages are associated with diapedesis due to immunologically mediated events. The interstitium has also been found to contain a lymphohistiocytic infiltrate with abundant plasma cells. No evidence has been reported of viral replication in any cell population.Abbreviations ASF African swine fever - ASFV African swine fever virus - C complement component - DNA deoxyribonucleic acid - HAD₅₀ 50% haemoadsorbing doses - Ig immunoglobulin - MPS mononuclear phagocytic system - PAS periodic acid-Schiff reagent     

猪瘟病毒E2蛋白在酵母中分泌表达条件的优化

影响外源基因在毕赤酵母中表达的因素很多，除了基因序列本身的内在特性外，表达条件对外源基因的表达量的高低也有着极显著的影响。本文对猪瘟病毒E2基因在毕赤酵母中不同的时间、不同的诱导型、不同的pH、不同的诱导剂量等方面表达量的差异进行了详细对比研究。结果表明，诱导后72～96h，重组E2蛋白的表达量最高。与单纯甲醇诱导相比，甘油／甲醇诱导后的表达量明显提高。在pH7．5和pH8．0表达E2蛋白是比较合适的。甲醇浓度在3％左右时E2蛋白的表达量较高。     

PCR结合分子杂交法检测鸡传染性支气管炎病毒

利用逆转录－ＰＣＲ（ＲＴ－ＰＣＲ）特异性扩增鸡传染性支气管炎病毒（ＩＢＶ）基因组中Ｍ基因和Ｎ基因之间一段核酸片段。以ｐＵＣ１９质粒载体将此片段克隆，用ＥｃｏＲＩ和ＨｉｎｄⅢ酶切此重组质粒，回收克隆片段后，制成生物素标记的核酸探针。用ＲＴ－ＰＣＲ及生物素核酸探针法分别对ＩＢＶ，ＩＢＤＶ，ＩＬＴＶ，ＭＤＶ及ＮＤＶ进行检测，结果证明该方法为ＩＢＶ特异性检测方法。对人工感染ＩＢＶ的ＳＰＦ鸡口腔棉拭样品进行跟踪检测，证明本方法能在ＳＰＦ鸡接毒后１～１０ｄ内检出ＩＢＶ。     

Spontaneous mosaicism occurred in normally fertilized and gynogenetically induced progeny of the kokanee salmon Oncorhynchus nerka

ABSTRACT:   In normally fertilized progeny of the kokanee salmon Oncorhynchus nerka , DNA content flow cytometry revealed that all the externally normal embryos were diploid, whereas abnormal embryos exhibited haplo-diploid, diplo-tetraploid and haplo-diplo-tetraploid mosaicisms, together with a few haploid and diploid individuals. When gynogenetic development was artificially induced by fertilization of eggs obtained from a female of the same kokanee brood stock with UV-irradiated sperm, haplo-diploid mosaics appeared most frequently. These mosaics were likely to happen by certain cytological events, such as meiotic or mitotic errors during the process of maturation, fertilization or early cleavage.     

Pestivirus infections in Norway. Serological investigations in cattle, sheep and pigs.

Serum samples from 1,133 dairy cows (187 herds), 3,712 ewes (103 flocks) and 1,317 adult pigs (877 herds), were tested for neutralizing antibodies against the NADL strain of bovine virus diarrhoea virus. The prevalence rate of seropositive animals was 18.5% in cattle, 4.5% in sheep and 2.2% in pigs, such seroreactors being found in 28% of the cattle herds and 18% of the sheep flocks. In all three species the rate showed considerable herd and geographical variation. In cattle the seroreactor rate was similar in herds with normal reproduction and in 62 herds with problems of repeat breeding. Of 31 pig sera containing antibodies against the NADL strain, 27 were also positive in a neutralization test for antibodies against swine fever virus (Baker strain). However, all sera showed a higher titre of antibodies against the bovine strain than against the swine fever virus. It was concluded that the immune response of the pigs had been induced by ruminant pestivirus, and not by swine fever virus.     

影响马立克氏病毒感染的因素及疫苗免疫策略

马立克氏病毒是高度细胞结合性、嗜淋巴组织的α疱疹病毒,其致病过程包括淋巴细胞的溶细胞感染和潜伏感染以及易感鸡体内CD 4 T细胞的致瘤性转化。宿主的遗传抗性、细胞免疫、体液免疫以及相关细胞因子和淋巴细胞等对M DV的感染过程有重要影响。针对M D肿瘤抗原的靶向免疫应答的保护性抗原分子和宿主细胞因子疫苗是今后疫苗研究的方向。     

烟草花叶病病株分布的观察

 通过在同一农户烟地15行烟草花叶病病株分布的观察,见有单株分布及连株分布两种.将连株分布中凡两株相邻的定为1个双株,三株相连的为2个双株,四株相连为3个双株,余类推.据范德普兰克的计算式,利用病株数计算双株数,与实查双株数比较.分辨出这些双株的传染方式,或为田间操作时通过接触茎叶传染,或为随机接触传染.在随机传染中,大量是经由根部在土壤中接触病残体所致,以致单纯用无病苗不能完全预防本病.     

鸽新城疫病毒QL株—些理化及培养特性

本试验对鸽新城疫病毒QL株在鸡胚中的培养特性、血凝素热稳定性及对甲醛溶液、胰蛋白酶等理化因素的影响进行了测定，结果为QL株接种鸡胚后96h生长达高峰，QL株可耐受56℃40min,0.1%甲醛溶液能完全灭活QL株尿囊液，且仍保持较好的抗原性，0.5%胰蛋白酶37℃消化30min后，血凝性升高。试验结果为合理利用QL株生产鸽新城疫疫苗提供了实验依据。