环核苷酸门控离子通道与疾病发生

细胞离子通道的结构和功能正常是维持生命过程的基础,其基因变异和功能障碍与许多疾病的发生和发展有关。文章综述了环核苷酸门控离子通道的类型、功能、研究方法及其与疾病的关系。     

猪肺炎霉形体致病机理的研究

猪肺炎霉形体是引起猪支原体性肺炎的病原体 ,此病是世界性危害猪群的疾病之一。本文探讨了其细胞膜荚膜 ,细胞膜蛋白 ,细胞膜膜脂与其致病性的关系 ,为解决猪支原体性肺炎提供了一些有用的信息。     

农业生产上几种重要的赤霉属真菌研究进展

赤霉属真菌大多是农业生产上具有破坏性的植物病原真菌。选取几种在农业生产上重要的赤霉属真菌来阐述该属在系统发生,生物学和化学上的多样性,并且比较了它们在分类学、遗传学、植物病理学和真菌毒理学方面的差异。虽然它们是非常近缘的赤霉属各种,但在繁殖方式、地理分布、寄主范围、植物致病机理、毒素和其他生物活性代谢物的产生方面都有所不同。     

病程相关蛋白质在水稻与白叶枯病菌互作过程中的表达

【目的】了解病程相关(pathogenesis-related,PR)蛋白质在植物防卫体系中的表达模式进而探讨水稻抗病的分子机理。【方法】选取10个前期工作中鉴定的差异转录PR基因,利用免疫印迹(Western blotting,WB)技术检测它们在水稻正常生长和与白叶枯病菌(Xanthomonas oryzae pv.oryzae Xoo)互作过程中的表达丰度变化。【结果】发现随着水稻的生长,Os12g43380、Os12g36830、Os12g36860、Os12g36840、Os02g41670、Os05g35290和Os12g33610的表达逐步增加,一般在开花期达到最高,成熟期有所降低。在白叶枯病抗性基因Xa21介导的水稻-Xoo非亲和互作过程中,检测到Os01g51570、Os01g71680和Os12g36850的表达量上调,Os12g36830、Os12g36840、Os02g41670和Os05g35290的表达量下调,并且发现,在亲和互作和非亲和互作反应中PR蛋白质的变化模式相似。对PR基因上游启动子区进行分析,发现存在与抗病相关的顺式作用元件,其中,ARE、HSE、MBS、TC-rich repeats等元件在抗病相关的PR基因上游出现频率较高。【结论】鉴定了在水稻-Xoo互作过程中发生丰度变化的7个PR蛋白质。     

Soluble interferon-γ receptors encoded by poxviruses

Poxviruses encode a broad range of proteins that counteract the formidable attack of the immune response initiated in the host after infection, among which are proteins that mimic the extracellular binding domain of host cytokine receptors and are secreted from virus-infected cells. A soluble interferon-γ receptor (IFN-γR) is produced early after infection and efficiently blocks the binding of IFN-γ to cellular receptors, thus inhibiting both the anti-viral and immune functions of IFN-γ. An IFN-γR is highly conserved among members of the poxvirus family, suggesting a major role in viral pathogenesis. The highly species-specific nature of the IFN system enables questions concerning the evolutionary relationship between poxviruses and their hosts to be addressed. The IFN-γR encoded by myxoma virus, a natural pathogen of rabbits, is specific for rabbit IFN-γ. However, the IFN-γR encoded by orthopoxviruses (vaccinia, cowpox, camelpox, ectromelia) shows a novel, broad species specificity suggesting that these viruses have evolved in several species. The implications for the unknown origin and natural host(s) of vaccinia virus are discussed.     

BVD virus antigens in tissues of persistently viraemic, clinically normal cattle: implications for the pathogenesis of clinically fatal disease

The cellular events involved in precipitation of the clinically fatal outcome of an infection with bovine viral diarrhoea virus (BVDV) remain unresolved, though it is now known that this course of the infection, Mucosal Disease (MD), only occurs in calves persistently infected with non-cytopathic BVDV. In studies aimed at elucidating the pathogenesis of MD, the distribution of BVDV antigens and infectious virus in tissues of persistently infected, clinically normal calves was investigated. Virus antigen was detected in most tissues, in epithelial and immune cells. No signs of an inflammatory response were detected and cytopathological changes were subtle or absent. The infection may nevertheless create a cell-environment which will enhance replication of cytopathic virus. Variations in the clinical, pathomorphologies and virological appearance of MD-cases may depend on both the host-reactions, including virus-induced immunopathology, and the virus-strain combinations in a putative mixed infection.     

Monitoring expression of selected Plasmodiophora brassicae genes during clubroot development in Arabidopsis thaliana

The expression of 12 cDNAs from Plasmodiophora brassicae , among them two novel sequences, was determined during clubroot development on Arabidopsis thaliana . The aim was to find cDNAs expressed at distinct stages of pathogenesis. The relative amount of infection with active plasmodia could be estimated using Pb Actin cDNA as an internal standard. Two cDNAs, Pb Brip9 and Pb CC249, were strongly expressed at stages of disease development corresponding to the occurrence of sporulating plasmodia. Therefore, it should be possible in the future to find more cDNAs which could be used as markers for certain stages of clubroot development.     

Mechanisms involved in the biological control ofBotrytis cinerea incited diseases

Mechanisms involved in the biological suppression of infection and inoculum potential ofBotrytis cinerea are numerous and variable and the involvement of two or more mechanisms has been demonstrated in several systems. Reported combinations include antibiosis with enzyme degradation ofB. cinerea cell walls; competition for nutrients followed by interference with pathogenicity enzymes of the pathogen or with induced resistance; and alteration of plant surface wettability combined with antibiosis. Since germinatingB. cinerea conidia are dependent on the presence of nutrients, competition for nutrients is regarded as important in systems where biocontrol is involved. Conidial viability and germination capacity are also potentially affected by the presence of antibiotics produced by biocontrol agents and present in the phyllosphere. Slower in action are mechanisms involving induced resistance in the host plant and production of hydrolytic enzymes that degradeB. cinerea cell walls. The latter has been demonstrated much more convincinglyin vitro than in the phyllosphere. Biocontrol in established lesions and reduction of sporulation on necrotic plant tissues is a means to minimize the pathogen inoculum.Abbreviations BCA bio-control agent - Bc Botrytis cinerea - PG polygalacturonase - PL Pectin lyase - PME Pectin methyl esterase - PR pathogenesis related - VPD vapour pressure deficit     

犬瘟热自然病例脱髓性脑病发生的机理

为了进一步调查脑组织的髓鞘脱失与神经胶质细胞等成份的关系,用12只犬瘟热自然病例通过病理组织学和免疫组织化学染色法进行了本试验.结果表明:髓鞘脱失部位的脑组织伴有明显的血液循环障碍,即淤血、水肿、血栓形成和弥漫性血管内凝血;少突胶质细胞发生代谢紊乱和凋亡;用抗犬瘟热病毒(CDV)抗体染色,星状胶质细胞呈现强阳性反应;用抗GFAP染色,纤维性星状胶质细胞在脱髓区呈较强阳性反应,用TUNEL染色可检出发生凋亡的星状胶质细胞;一些室管膜细胞也被CDV感染,许多含有包涵体币口凋亡的室管膜细胞在脑室壁被发现;少数神经元变性和皱缩,其核发生浓缩.据此认为,脑组织的髓鞘脱失主要与血液循环障碍和少突胶质细胞的代谢紊乱及凋亡有关;脑组织的髓鞘脱失是许多病因共同作用的结果,并非是一种病因所致.