病原微生物荚膜多糖的生物学功能   总被引：2，自引：1，他引：1  

谢黎卿  杨洋  彭远义  李能章 《畜牧兽医学报》2021,52(3):576-587

荚膜多糖（capsular polysaccharide，CPS）是一种广泛存在于细菌、支原体、部分真菌等菌体表面的碳水化合物。同时，荚膜多糖有助于菌体抵抗干燥和低温等不利环境，并通过在菌体表面形成物理屏障阻碍宿主补体的杀伤与吞噬作用。在长期多种应激-压力环境下，病原菌已进化出多种免疫逃避机制并促进宿主感染；在非病原微生物中，荚膜多糖可正向调节宿主免疫作用，并拮抗机体免疫因子，保护宿主免受病原菌引起的炎症性疾病。本文将结合本团队的相关研究工作，对荚膜多糖的结构、合成调控机制、生物学功能、免疫逃避机制和致病机制，特别是荚膜多糖正向调节宿主免疫系统及其应用潜力等方面作一综述，为病原菌致病机制的研究和疫病的有效防控提供参考依据。  相似文献   

Age estimation of different tree species using a special kind of an electrically recording resistance drill     

《Urban Forestry & Urban Greening》2018

The determination of tree age is an important issue for urban green planning, forestry and dendrology; finding non-destructive and quasi-non-destructive methods for this purpose is of great theoretical and practical importance. The resistance drilling method is quasi-non-destructive because the average diameter of an opening that remains after drilling does not exceed 3 mm. Do electrically recording resistance drills allow precise assessment of tree age? The aim of this study is to assess the accuracy of determining the number of tree rings based on an examination of this special kind of drilling resistance profiles for three tree species, the pine Pinus sylvestris L., the oak Quercus robur L., and the birch Betula pendula ROTH. In 2015 and 2016, 15 pine trees, 15 oak trees, and 15 birch trees were randomly selected. For each studied tree, a measurement was conducted using the electrically recording resistance drill IML-Resi E400 with a flat-tipped 1.5/3 mm steel needle (research sample), and an increment core was taken (reference sample). The drill used was not a real Resistograph^®. The analysis of the E400-profiles underestimated the number of tree rings; the mean bias error (MBE) values were –6.5, –2.5, and –6.0 years for pine, oak, and birch, respectively. The proportion of investigated trees with less than five years difference between the research and reference samples varied from 38.4 (birch) to 66.7 (oak) percent. The accuracy of tree age determination was lowest for birch and highest for oak. The binomial generalised linear model (GLM) revealed that the most accurate tree age assessments were obtained from tree rings wider than 2 mm. The measurements clearly showed that the electrically recording resistance drill IML-Resi E400 enables a quick, although approximate, tree age assessment. Future research should concentrate on electronically regulating and recording drills, providing a higher spatial and signal resolution, and a stronger correlation to wood density.  相似文献   

FoxA2 and p53 regulate the transcription of HSD17B1 in ovarian granulosa cells of pigs     

Xiaolong Yuan  Xiaofeng Zhou  Xiwu Qiao  Qi Wu  Zhixiang Yao  Yao Jiang  Hao Zhang  Zhe Zhang  Xilong Wang  Jiaqi Li 《Reproduction in domestic animals》2021,56(1):74-82

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智慧图书馆微观知识生态系统运行机理研究     

李大莉  陈德云  卜琳琳  丁莉  王秀芳 《农业图书情报学刊》2018,30(12):70-73

伴随多元化时代的来临,用户的知识需求日益多元化、专业化,对图书馆服务提出了新的挑战。对智慧图书馆微观知识生态系统运行机理的研究,能够为新型知识服务提供理论基础,保障知识资源进行有效的优化整合,实现服务升级。文章在简要分析智慧图书馆微观知识生态系统四大要素的基础上,着重从社会发展、技术进步,知识富集、优化调整和需求驱动、服务升级三方面探讨其形成动因,重点分析智慧图书馆微观知识生态系统的生命周期,最后从合作、循环和保障三方面探讨其运行机理。  相似文献   

New Polyketides from the Antarctic Fungus Pseudogymnoascus sp. HSX2#-11     

Ting Shi  Yan-Yan Yu  Jia-Jia Dai  Yi-Ting Zhang  Wen-Peng Hu  Li Zheng  Da-Yong Shi 《Marine drugs》2021,19(3)

The species Pseudogymnoascus is known as a psychrophilic pathogenic fungus with a ubiquitous distribution in Antarctica. Meanwhile, the study of its secondary metabolites is infrequent. Systematic research of the metabolites of the fungus Pseudogymnoascus sp. HSX2#-11, guided by the method of molecular networking, led to the isolation of one novel polyketide, pseudophenone A (1), along with six known analogs (2–7). The structure of the new compound was elucidated by extensive spectroscopic investigation and single-crystal X-ray diffraction. Pseudophenone A (1) is a dimer of diphenyl ketone and diphenyl ether, and there is only one analog of 1 to the best of our knowledge. Compounds 1 and 2 exhibited antibacterial activities against a panel of strains. This is the first time to use molecular networking to study the metabolic profiles of Antarctica fungi.  相似文献   

Identification of an H1N1 subtype of swine influenza virus and serological analysis     

Fa-chao SUN  Min TAN  Yuan-chao ZHANG  Yu-chao WANG  Sheng-liang CAO  Guo-fei DING  Fang-yuan CONG  Li-hong GUO  Si-dang LIU  Yi-hong XIAO 《农业科学学报》2019,18(7):1436-1442

To investigate the epizootic of swine influenza virus(SIV), 60 nasal swabs were collected from a clinical cases of pig farm in Tai'an City, Shandong Province of China in April 2017. SIV was isolated by inoculating into 10-day-old Special Pathogen Free embryonated eggs and the whole genome was sequenced. An H1N1 subtype SIV was isolated and designated as A/swine/Shandong/TA04/2017(H1N1). Phylogenetic analysis showed that apart from the polymerase A(PA) fragment belonging to the 2009 pandemic H1N1 branch, seven genome segments belonged to avian-like H1N1 influenza virus lineage. The cleavage site sequence of the hemagglutinin(HA) protein was PSIQSR↓G, which is a typical molecular biological characteristic. Five potential N-glycosylation sites(N14, N26, N277, N484 and N543) were found in the HA gene. To further investigate the epidemiology of SIV in this farm, the 995 serum samples were assessed with EAH1N1 2009 pandemic H1N1 and H3 N2 antigens. The results showed that the total positive rate was 65.43%. The positive rates of single virus infection detected by EAH1N1, 2009 pdmH1N1 and H3 N2 for serum HI(Hemagglutination inhibition) were 48.35, 30.85 and 7.47%, respectively. The results showed that SIV in Shandong Province has been reassorted in some segments and the SIV-positive rate was high on the SIV outbreak farm. These data provide evidence of an epizootic of SIV.  相似文献   

Transcriptome Analysis of Myzus persicae to UV-B Stress     

Chang-Li Yang  Jian-Yu Meng  Meng-Shuang Yao  Chang-Yu Zhang 《Journal of insect science (Online)》2021,21(3)

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Differential regulation on C5 expression in goose versus mammals by glucose/palmitate provides a potential protection for goose fatty liver     

Zidi Jin  Long Liu  Cheng Xu  Chunchi Yan  Shuo Li  Tuoyu Geng  Daoqing Gong 《Animal Science Journal》2021,92(1):e13672

Goose fatty liver is a specific type of nonalcoholic fatty liver that is protected from harmful effects associated with severe steatosis. Our previous findings suggest that suppression of the complement C5 may be relevant, but the mechanism is unclear. Therefore, in this study, we first verified the expression pattern of complement genes (including C5) during goose fatty liver formation and then determined the liver fat content and fatty acid composition by high-performance liquid chromatography (HPLC), followed by selecting the differential metabolites to treat HepG2, goose and mouse primary hepatocytes, aiming to explore the mechanism of C5 and inflammation suppression in goose fatty liver. The data confirmed the suppression of complement genes (including C5) in goose fatty livers. Moreover, fat content was significantly higher in fatty liver versus normal ones, with oleic acid and palmitic acid dominantly accounting for the difference. In line with this, high concentration of palmitate led to down regulation of C5 expression in goose primary hepatocytes whereas upregulation in mouse primary hepatocytes and HepG2 cells. In conclusion, regulation on C5 expression by fatty liver related factors including high level of palmitic acid may contribute to the protection of goose liver from severe hepatic steatosis.  相似文献   

Essential Factors and Sustainable Development of Green Agriculture     

WANG Hong 《东北农业大学学报(英文版)》2009,16(2):83-90

This paper discussed the definition and essential factors of green agriculture, including green ecological environment, green material energy input, application and the popularization of green agricultural technology, the green behavior of worker, green policy regulations guarantee, fund support, supply and the production of green agriculture products, as well as the concept of green agriculture, structural mechanism and function. And finally existing problems in present green agriculture and five suggestions of green agricultural sustainable develonment were proposed.  相似文献   

脂肪细胞膜免疫降脂的研究     

姚华  王俊东  李宏全 《四川畜牧兽医》2003,30(9):24-26

本文综述了利用脂肪细胞膜免疫技术进行畜禽脂肪代谢研究的成果，其技术路线主要包括试验途径和方法、免疫机理、降脂效果及特异性脂肪膜蛋白的研究启示，从而为脂肪细胞膜免疫降脂试验提供成功的范例和科学的依据，并开辟降低脂肪、提高瘦肉率研究的新领域。  相似文献