沙门氏菌的研究进展

作者就沙门氏菌的毒力岛、质粒、致病机制和流行病学方面的研究作了简明扼要的概述,对沙门氏菌的防治研究具有重要的参考价值。     

The Hydropericardium Syndrome in Poultry – A Current Scenario

Inclusion-body hepatitis hydropericardium syndrome (IBH-HPS) is an important, recently emerged, disease of poultry, particularly of 3- to 6-week-old broiler chicks, characterized by its sudden onset, with high mortality ranging from 20% to 70%, typical hydropericardium and enlarged mottled and friable livers, with intranuclear inclusion bodies in the hepatocytes. The causative agent is a non-enveloped icosahedral fowl adenovirus (FAV) serotype 4, belonging to the Adenovirus genus of the family Adenoviridae, which can be propagated or cultivated in chicken embryo liver and kidney primary cell cultures. The transmission of disease occurs vertically and laterally by the oral-faecal route. The liver of infected birds shows necrotic foci and basophilic intranuclear inclusion bodies in the hepatocytes. The disease can be diagnosed from its gross and histopathological changes in the liver and by various serological tests, such as agar gel immunodiffusion, counterimmunoelectrophoresis, indirect haemagglutination, the fluorescent antibody technique, enzyme-linked immunosorbent assay and the polymerase chain reaction. The disease has been brought under control by the use of formalin-inactivated vaccines, prepared from infected liver homogenate, and of inactivated cell culture vaccines. The vaccines are effective in the face of natural outbreaks or experimental challenge and significantly reduce the mortality.     

细胞凋亡与细胞坏死比较的研究进展

本文对细胞凋亡和细胞坏死的发病机理和病理形态学进行了比较。凋亡是细胞的一种主动性死亡。其特点是单细胞发生,胞核浓缩、破裂,核碎块被胞膜包裹,形成特异性“凋亡小体”;细胞器多以萎缩变化为主。坏死则为细胞的被动性死亡,并常伴有炎症反应。作者认为：细胞凋亡和坏死虽然在发生机制和病理形态学方面有所区别,但它们的本质却是相同的,均为细胞的一种不可复性的退行性变化。     

革兰氏阴性菌外膜蛋白研究进展

外膜蛋白对细菌本身和宿主都具有重要的作用。本文综述了革兰氏阴性菌外膜蛋白的组成、结构、功能及遗传调控,外膜蛋白可作为大肠杆菌的克隆标志,在细菌的致病机理及免疫机理中都有重要作用,研制开发外膜蛋白疫苗具有广阔的应用前景,必将为细菌性疾病的防治提供有力的措施。     

脱氧雪腐镰刀菌烯醇在小麦赤霉病病程中的作用

 脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)系小麦赤霉病菌——禾谷镰孢(Fusarium graminearum,有性态Gibberell azeae)产生的一种单端孢霉烯族毒素(trichothecenes,以下简称"单族毒素")。作者以病菌正常产毒的野生型菌株GZ3639及其产毒基因Tri5损坏、不能产毒的转化子GZT40(Tri5^-,TRI^-)为材料,对DON在病菌致病过程中的作用进行了研究。结果显示:GZ3639能引起典型的赤霉病症状,病害可由接种小花发展至其它小穗,病菌也可定殖于其它小穗组织;而GZT40仅在接种小花处产生鸟眼状坏死斑点,不能引起典型的赤霉病症状,病菌仅定殖于接种小花处。当病菌与一定浓度(400 μ g·mL^-1)的DON混合处理小花后,GZT40的定殖时间提前2 d (感病品种上)至4 d (抗病品种上),定殖范围可扩大到1~3个小穗,接种20 d后的病小穗率也由病菌单独接种时的2.8%提高到12.5%。DON也使GZ3639的定殖时间提前1 d (感病品种上)至2 d (抗病品种上),定殖范围更广,其所致的病害发展更迅速,接种后20 d的病小穗率由病菌单独接种时的78.0%提高到100%。因此,作者认为,单族毒素在病害发展和病菌在寄主组织内的扩展中起着决定性作用,一旦丧失产毒能力,病菌虽能侵入寄主,但不能在寄主组织中扩展。DON可以缩短病菌成功定殖寄主所需的时间,更有助于病菌在寄主组织内的扩展。     

植物病原真菌致病机理研究进展

真菌是最重要的植物病原类群,植物病原真菌致病机理的研究是当今植物病理学领域的热点问题之一,了解植物与病原菌的互作对有效控制病原菌危害和选育抗病品种具有重要意义。本文从病原菌侵染结构(侵染垫、附着胞、吸器)的形成和功能、主要致病因子(细胞壁降解酶、毒素)的产生和作用、侵染过程的分子基础,以及病原菌侵染后植物膜质过氧化、活性氧清除系统和防御酶系统的变化等方面,综合阐述了植物病原真菌致病机理的研究进展,并就目前存在的问题和研究前景进行了展望。     

犬感染性心内膜炎研究进展

感染性心内膜炎(Infective Endocarditis,IE)是犬的一种致命性疾病,由病原微生物侵入心脏瓣膜或心内膜内皮细胞所引发。细菌是从病变瓣膜和壁内膜组织中分离的主要病原体,因此也称细菌性心内膜炎。临床上,犬患IE并不常见,但一旦发生,死亡率极高。IE由于病情发展迅速,缺乏特异性的临床症状,因此早期诊断比较困难。文章主要从发病机制、临床症状、诊断、治疗等方面对犬IE进行了综述,为有效防治该病提供依据。     

槟榔在口腔黏膜下纤维性变发病机制中的作用

口腔黏膜下纤维性变（Oral Submucous Fibrosis，OSF）是一种以炎症和渐进性黏膜改变导致进行性张口困难为特征的口腔黏膜慢性病症．近年来相当多的流行病学研究资料指出槟榔是OSF的主要病源因子，在OSF的发病上，不论是嚼食槟榔的频率还是持续的时间都呈现了剂量依赖性．在嚼食槟榔时粗糙纤维对口腔黏膜产生的强烈机械刺激作用、槟榔中的生物碱与单宁对细胞外基质分子的影响以及槟榔中的铜在纤维化疾病中的作用等方面对槟榔在OSF发病原因与发病机制中的作用加以综述，旨在分析迄今为止国内外学者对槟榔在OSF上所做的研究，以期让基础科研人员、公共卫生工作者以及广大槟榔嗜好者对槟榔在人类OSF中的作用有更深入的了解．     

Pathogenesis and epidemiology of spontaneous exophthalmos in the West Australian dhufish, Glaucosoma hebraicum Richardson

The West Australian dhufish, Glaucosoma hebraicum Richardson (family Glaucosomatidae) is a potentially valuable aquaculture species, but spontaneous exophthalmos is common in freshly caught and cultured dhufish. To investigate the epidemiology and pathogenesis of exophthalmos in tanks of wild-caught and captive-bred dhufish, records of culture conditions, the prevalence of lesions and pathological examinations were used to study the disease and associated environmental and management factors. Naturally occurring cases of exophthalmos that were examined were mostly unilateral and occurred more frequently in summer months during periods of increasing water temperature. In 15 affected eyes that were examined histologically gas bubbles and haemorrhages were consistently present in the choroid. In some, gas bubbles and haemorrhage were also present in retrobulbar tissues associated with perforation of the sclera. Oxygen concentrations were measured in 12 exophthalmic eyes and concentrations of 50–73% were recorded in gas bubbles in the anterior chamber of three of these that were acute cases. Very low oxygen tensions were recorded at the retinal–vitreal junction of four eyes with retrobulbar haemorrhages indicating that there may have been disruption of arterial blood supply to the choroid in chronic lesions or with perforation of the sclera. The results of experiments to determine the significance of exercise, high water temperature, sudden increases in light intensity, fish handling or tank cleaning indicate that exercise and/or high water temperature (25.5 °C) may be important risk factors for the development of exophthalmos in dhufish. Possible mechanisms for the formation of gas bubbles and haemorrhage in the choroid are discussed.     

Histopathological studies on viral nervous necrosis of sevenband grouper, Epinephelus septemfasciatus Thunberg, at the grow-out stage

Abstract Viral nervous necrosis caused by sevenband grouper nervous necrosis virus (SGNNV) has occurred in grow-out stages (0-3 years old) of sevenband grouper, Epinephelus septemfasciatus, since the 1980s. In the present study, based on histopathological features of the central nervous system (CNS) in naturally diseased fish, pernasal infection experiments using grow-out fish were performed and pernasal infection was established as a putative invasion route of SGNNV. The definite SGNNV-targeted cells were determined by histopathological studies including indirect fluorescent antibody test and electron microscopy. Nerve cells in the olfactory lobe were most extensively necrotized with vacuolation followed by infiltration of microglia and macrophages. Purkinje cells and Golgi cells were extensively infected in the cerebellum. Megalocells and small nerve cell nuclei were also infected in the preoptic area, thalamus, medulla oblongata and spinal cord. Only a few small nerve cells were infected in the olfactory bulb and optic tectum. The retina of some diseased fish displayed vacuolated bipolar cells of the inner nuclear layer and in the ganglion cell layer. These SGNNV-infected nerve cells displayed viroplasmic inclusions containing virions, vacuoles and myelin-like structures. Based on observed histopathological changes, the lesion of the CNS was characterized by encephalitis but not encephalopathy.