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非洲猪瘟对家庭猪场的生产稳定性带来极大的挑战。文章分析了家庭猪场防控非洲猪瘟存在的问题及对关键点针对性的防控措施。 相似文献
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Bruno B. Chomel Henri-Jean Boulouis Edward B. Breitschwerdt Rickie W. Kasten Muriel Vayssier-Taussat Richard J. Birtles Jane E. Koehler Christoph Dehio 《Veterinary research》2009,40(2)
Bartonella spp. are facultative intracellular bacteria that cause characteristic host-restricted hemotropic infections in mammals and are typically transmitted by blood-sucking arthropods. In the mammalian reservoir, these bacteria initially infect a yet unrecognized primary niche, which seeds organisms into the blood stream leading to the establishment of a long-lasting intra-erythrocytic bacteremia as the hall-mark of infection. Bacterial type IV secretion systems, which are supra-molecular transporters ancestrally related to bacterial conjugation systems, represent crucial pathogenicity factors that have contributed to a radial expansion of the Bartonella lineage in nature by facilitating adaptation to unique mammalian hosts. On the molecular level, the type IV secretion system VirB/VirD4 is known to translocate a cocktail of different effector proteins into host cells, which subvert multiple cellular functions to the benefit of the infecting pathogen. Furthermore, bacterial adhesins mediate a critical, early step in the pathogenesis of the bartonellae by binding to extracellular matrix components of host cells, which leads to firm bacterial adhesion to the cell surface as a prerequisite for the efficient translocation of type IV secretion effector proteins. The best-studied adhesins in bartonellae are the orthologous trimeric autotransporter adhesins, BadA in Bartonella henselae and the Vomp family in Bartonella quintana. Genetic diversity and strain variability also appear to enhance the ability of bartonellae to invade not only specific reservoir hosts, but also accidental hosts, as shown for B. henselae. Bartonellae have been identified in many different blood-sucking arthropods, in which they are typically found to cause extracellular infections of the mid-gut epithelium. Adaptation to specific vectors and reservoirs seems to be a common strategy of bartonellae for transmission and host diversity. However, knowledge regarding arthropod specificity/restriction, the mode of transmission, and the bacterial factors involved in arthropod infection and transmission is still limited. 相似文献
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Overexpression of a small heat‐shock‐protein gene enhances tolerance to abiotic stresses in rice 下载免费PDF全文
Rice (Oryza sativa L.) is one of the most important crops in the world which survives from various abiotic stresses in natural environments with specific stress‐involved genes expressed. Plant sHSPs (small heat‐shock proteins) were reported to respond to abiotic stresses. To improve the understanding of sHSPs in rice, we characterized heat‐shock‐protein gene OsHSP18.6 here. OsHSP18.6 could be induced by diverse stresses, such as drought, salt and cold, especially under heat. The gene was found expressed in root, stem, leaf, internode and spikelet. Overexpression of OsHSP18.6 results in increased thermotolerance and exhibits universal tolerance to stresses tested, including heat, drought, salt and cold. Lower levels of malondialdehyde (MDA) and greater activities of catalase (CAT) and superoxide dismutase (SOD) were observed in OsHSP18.6‐overexpression rice under heat and drought. OsHSP18.6‐overexpression lines indicated decreased sterile rates under hot weather without remarkable changes in most of other agronomic traits compared with wild‐type plants. 相似文献