The pathogenicity and pathogenesis of Mycoplasma capricolum subsp. capripneumoniae (F38) in the caprine mammary gland

The right mammary gland of 12 lactating goats was inoculated intracisternally with 1 ml of Mycoplasma capricolum subsp. capripneumoniae (Mcc) containing 10>⁶ colony-forming units (CFU), while their left mammary halves received 1 ml of sterile PPLO broth only. Two goats served as uninfected controls. The clinical mastitis that developed in the infected mammary halves within 24 h was initially acute but became increasingly chronic by the end of the experiment at 24 days post inoculation (DPI). The disease was characterized by atrophy of the infected mammary halves, leading to marked agalactia and an increase in somatic cell counts, with a preponderance of neutrophils initially and lymphocytes later. The Mycoplasma was re-isolated from infected mammary secretions up to 16 DPI but not from blood. Histopathology revealed that the mastitis was acute and purulent initially, followed by infiltration of lymphonuclear cells and fibroplasia in the lymphomononuclear cells and fibroplasia in the interacinar tissue, and later by massive fibrosis. Immunohistology demonstrated the presence of Mycoplasma-like bodies localized mainly on the surface of acinar/duct epithelial cells. The studies showed that Mcc was highly pathogenic in the caprine mammary gland.     

猪附红细胞体病研究进展

附红细胞体病是由附红细胞体寄生于红细胞表面、血浆及骨髓所引起的一种人兽共患传染病.该病分布范围广、感染宿主种类多,给人类的健康和畜牧业的发展带来巨大的危害,其中以猪附红细胞体病最为严重.文章根据国内外有关文献,结合科学研究和临床实践,对猪附红细胞体病的病原学、流行病学、发病机理、临床表现、血液学变化、病理变化、诊断及防治等进行了综述,以期为进一步研究附红细胞体病的致病机理和防治措施提供理论依据.     

狂犬病发病机理的研究进展

狂犬病是由狂犬病病毒引起的一种重要的人兽共患传染病,在人主要表现为急性、几乎不可逆转的脑脊髓炎,目前没有有效的治疗方法,病死率几乎100%。目前对狂犬病病毒感染和狂犬病发病机理的认识还很不透彻,但近年来的研究也取得了不少进展,主要涉及狂犬病病毒受体、神经细胞功能失调的原因和神经细胞凋亡机制、狂犬病病毒与机体免疫系统相互作用机制,狂暴型和麻痹型狂犬病的发病机制,这些都将为狂犬病的治疗研究起到推动作用。     

犬冠状病毒病的免疫预防研究进展

犬冠状病毒病是由犬冠状病毒引起的以胃肠炎为主的一种高度接触性传染病,对幼犬危害尤其严重,发病率和死亡率都很高,是目前对养犬业危害较大的疾病之一.文章就犬冠状病毒感染的流行病学、发病机理、机体免疫、免疫程序和免疫预防进行了综述,特别是对犬冠状病毒病的免疫类型、疫苗种类以及免疫预防存在的问题进行了详细阐述.     

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。