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91.
2批猪瘟兔化毒睾丸细胞苗分别来自两家兽医生物药品厂,各分别免疫接种猪只,随后以5株猪瘟病毒野毒分别攻击,疫苗接种猪完全存活,对照猪完全死亡。此5株野毒分离自国内不同地区,并皆已经过细致的鉴定,以免疫荧光技术对猪扁桃体进行了活体检查,各对照猪材料上能在攻击后一周时出现病毒,而疫苗接种猪在整个观察期间未出现病毒,据此,显然可见猪瘟兔化毒细胞苗在预防国内猪瘟上极有效力  相似文献   
92.
Information about motile aeromonads from aquaculture systems of the Neotropical region is scarce. The aim of this study was to characterize motile Aeromonas isolated from ornamental and consumable fishes cultured in Uruguay. Biochemical and molecular methods were used for species identification. Antimicrobial susceptibility and the presence of virulence genes were evaluated. Genetic diversity was analysed by rep‐PCR, and virulence of the most representative isolates was determined by calculating the fifty lethal dose in experimentally challenged fish (Australoheros facetus). Aeromonas hydrophila and A. veronii were the most prevalent identified species (38.2% and 32.4%, respectively), whereas A. allosacharophila, A. bestiarium, A. caviae and A. punctata were less prevalent. This study constitutes the first report of these last four species in Uruguay. All isolates were resistant to at least three antimicrobials, and 82.3% of them showed multidrug resistance. Virulence genotypes were correlated with the Aeromonas species and haemolytic activity. The genotype act+/alt+/ast+/ela+/lip+ was the most prevalent (26.5%). A correlation between virulence genotypes and Aeromonas species was found. A. punctata showed a clonal structure according to rep‐PCR analysis, whereas other species showed high genetic diversity. The number of virulence genes of the isolates was related with virulence according to the experimental challenge assays.  相似文献   
93.
生物农药的推广有助于克服传统农药生产和使用不当造成的农产品质量安全和环境污染问题。但是我国目前在生物农药研发、推广和销售等方面存在人才储备、资金和政策支持不足,产业发展初期各主体间协作和成果落地转化不够,标准体系和产业化发展不充分,对农业产业和生态环境认识欠缺等问题。为克服弊端,可从立足农业生产现实、把握未来研发方向、加强多元机制建设、保证生物农药推广落地、形成我国生物农药核心竞争力几条思路出发,把握机遇、迎接挑战。  相似文献   
94.
目的 构建串联SpaA优势表位的丹毒亚单位疫苗,并对其免疫原性进行研究。方法 将丹毒杆菌表面保护抗原A优势表位串联表达,提取并经亲和层析纯化获得重组蛋白,制备亚单位疫苗,免疫小鼠和猪,21日后攻毒。结果 成功制备串联SpaA优势表位的丹毒亚单位疫苗,2μg重组蛋白可为小鼠抵抗1000MLD强毒攻击提供100%保护,100μg重组蛋白可为猪抵抗1MLD强毒攻击提供100%保护,可为猪抵抗2MLD强毒攻击提供67%保护。结论 串联SpaA优势表位的丹毒亚单位疫苗具有良好的免疫原性,高于商品化疫苗保护标准。  相似文献   
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The incidence of disease caused by Pasteurella sp. in farmed lumpsuckers in Norway has been steadily increasing in recent years, causing significant economic losses and fish welfare issues. The disease affects all life stages, both in hatcheries and after release into salmon cages. Therefore, it is important to establish robust challenge models, to be used for vaccine development. Exposure experiments via intramuscular and intraperitoneal injection underlined the high virulence of the bacteria, whereas the cohabitation and bath models allowed the chronic symptoms of the disease to be studied more accurately. Skin lesions and haemorrhage at the base of fins were observed in the more acute cases of the disease. Symptoms including white spots over the skin, especially around the eyes, characterized the chronic cases. The latter were most prominent from the bath challenge model. Histopathology indicated a systemic pattern of disease, whereas qPCR analysis from head kidney showed that bacteria may be present in survivor fish at the end of the challenges. In all the challenge models investigated, Pasteurella sp. was re‐isolated from the fish, thus fulfilling Koch's postulates. These findings highlight the importance of screening of lumpsuckers prior to transfer to minimize the risks of carrying over asymptomatic carriers.  相似文献   
98.
Making hair cortisol as the gold standard of reflecting chronic stress level is prospective and innovative.Hair cortisol not only can be used in detecting and estimating the chronic stress level of animals, but also can be benefit for understanding the body's physiological and pathological process and making effective health management strategy in time.Blood, saliva, urine and milk cortisol concentrations can be regarded as matrices for reflecting acute stress level as well, they have been used in detecting and establishing the diurnal profile of circulating cortisol studying.But hair which is a good supplementary matric can reflect the chronic stress level retrospectively.Hair cortisol as a reflection of the biochemical markers of chronic stress has the advantages of no invasive, relatively sensitive detection and convenient sampling stress, and hair cortisol is a heritable trait (h2=0.31).The utility of hair cortisol as a maker for HPA activity, and a useful tool for identifying genetic variation influences on long term individual differences in HPA activity.This article summarized the relationship between the cortisol and animal's healthy, the regulating mechanism and genetic adaptation change under chronic stress and the research progress of evaluation indicators during chronic stress, the research progress of hair as a matric of cortisol, the limitations and challenge of regarding hair cortisol as the biochemical marker to reflect the chronic stress level in the future.  相似文献   
99.
中国入世,既是一种机遇,也是一种挑战,我国将按照国际惯例展开世界贸易,而会计作为一种国际通用商业语言,由于有其技术属性和社会属性的特点,加入WTO必将给我国会计领域带来严峻的影响与挑战。  相似文献   
100.
我国加入WTO后 ,我国关税已基本符合发展中国家入世条件 ,经济全球化这将有利于湖北省人造板业、家居装饰业的发展。湖北省林产工业应正视机遇 ,提高认识 ,优化产业结构 ,加大技术进步与引进 ,加速速生丰产基地建设。  相似文献   
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