全球变化背景下的现代生态学——第六届现代生态学讲座纪要

"现代生态学讲座"是由著名生态学家李博院士创导,国内外华人生态学家联合发起,旨在促进中国现代生态学与世界同步发展,加强国内外生态学界交流与合作的国际会议。2011年8月1-4日在南京大学举行的第六届现代生态学讲座围绕"全球背景下现代生态学热点问题及其研究进展"主题,进行了23场特邀专家学术讲座,从全球变化背景下:现代生态学方法论、全球变化与陆地生态系统的响应与反馈、全球变化背景下的生物入侵、全球变化背景下的森林生态、全球变化背景下的植物生理生态、全球变化背景下退化生态系统恢复与重建、全球变化背景下的生态水文、全球变化背景下的区域生态管理等八个方面进行分类总结,从不同时空尺度、不同学科角度探讨全球变化与生态系统的响应以及人类为实现可持续发展而采取的适应性管理对策。最后,对会议的进一步完善提出几点建议。     

镜泊湖岩溶台地不同植被类型土壤微生物群落特征

为了探讨不同演替阶段植被类型土壤微生物群落特征,分别选取镜泊湖岩溶台地草本、矮灌木、高灌木、小乔木与灌木混生(简称混生)群落、落叶阔叶林及针阔混交林6种典型植被类型,进行植物群落调查和对土壤微生物生物量、群落结构和多样性指标、土壤物理化学性质的测定。结果表明：从土壤微生物量、土壤微生物群落组成、土壤微生物代谢动力学过程和代谢功能多样性的角度来看,各种植被类型土壤微生物群落具有明显的差异。演替前期的草本群落土壤微生物量碳氮、细菌生物量、真菌生物量,代谢活性及丰富度指数均最低,但Shannon-Wiener多样性指数和均匀度指数显著(P<0.05)高于其他植被类型。矮灌木土壤微生物群落组成显著受植被类型的影响。高灌木群落和混生(小乔木与灌木混生)群落具有极强的相似性, 但在碳源利用类型上两者表现出一定的差异。落叶阔叶林代谢活性最高,碳源利用能力最强,能利用BIOLOG微孔板中的所有31种碳源,这与其具有较高的微生物量碳氮和细菌生物量一致,其代谢功能丰富度最高。演替后期的针阔混交林下的土壤pH最低,真菌比例升高,在碳源丰富的条件下具有极强的竞争优势(仅次于落叶阔叶林),但在碳源贫瘠的条件下其利用碳源能力较弱(仅高于草本)。植被可能主要通过土壤全磷和有机质影响土壤微生物代谢功能多样性。     

日粮添加复合饲用益生菌对肉牛生长性能及肠道微生物的影响

[目的]为研究添加饲用益生菌对肉牛生长性能、血液生理生化指标及肠道微生物区系的影响.[方法]在青海地区选取西门塔尔牛与荷斯坦牛的杂交1代18头,按每组平均体重相近的原则随机分为2组,每组9头,试验组饮食添加地衣芽孢杆菌、枯草芽孢杆菌和酿酒酵母的复合饲用益生菌.[结果]试验结果表明:试验组显著地提高了胸围日增长量(P=0...     

灵芝免疫调节蛋白(Lz-8)在毕赤酵母中的表达及其免疫活性鉴定

真菌免疫调节蛋白家族(Fungi immunoregulatory proteins,FIPs)各成员所具有的免疫调节和抗肿瘤活性已被广泛研究。本研究利用毕赤酵母表达系统对其成员Lz-8进行了重组表达。以毕赤酵母突变株GS115为表达宿主细胞,PCR和DNA测序结果均显示Lz-8的cDNA已被成功地整合入酵母基因组。聚丙烯酰胺凝胶电泳(SDS-PAGE)、激光解析飞行时间质谱(MALDI-TOF-MS)和免疫学实验均被用于重组表达蛋白的检测。实验结果表明Lz-8在毕赤酵母表达系统中得到成功表达,在SDS-PAGE中可观察到分子量为14000D的单一条带,MALDI-TOF-MS的实验结果显示rLz-8的分子量为12722D。在相关的免疫学实验中,rLz-8可引起绵羊血红细胞凝集,但对人血4种血型的红细胞并没有凝集作用,rlz-8还可诱导巨噬细胞吞噬作用,均与其他报道中的实验结果吻合。以上结果表明,本实验已成功地利用毕赤酵母表达系统对Lz-8进行重组表达。     

Decomposition time,chemical traits and climatic factors determine litter-mixing effects on decomposition in an alpine steppe ecosystem in Northern Tibet

Plant and Soil - In the context of rapid species diversity loss, whether and how species diversity affects litter decomposition in alpine ecosystems remain unclear. Here, we aimed to assess the...     

Discovery of liver-targeted inhibitors of stearoyl-CoA desaturase (SCD1)

Inhibitors based on a benzo-fused spirocyclic oxazepine scaffold were discovered for stearoyl-coenzyme A (CoA) desaturase 1 (SCD1) and subsequently optimized to potent compounds with favorable pharmacokinetic profiles and in vivo efficacy in reducing the desaturation index in a mouse model. Initial optimization revealed potency preferences for the oxazepine core and benzylic positions, while substituents on the piperidine portions were more tolerant and allowed for tuning of potency and PK properties. After preparation and testing of a range of functional groups on the piperidine nitrogen, three classes of analogs were identified with single digit nanomolar potency: glycine amides, heterocycle-linked amides, and thiazoles. Responding to concerns about target localization and potential mechanism-based side effects, an initial effort was also made to improve liver concentration in an available rat PK model. An advanced compound 17m with a 5-carboxy-2-thiazole substructure appended to the spirocyclic piperidine scaffold was developed which satisfied the in vitro and in vivo requirements for more detailed studies.     

Mechanically Activated Piezo Channels Mediate Touch and Suppress Acute Mechanical Pain Response in Mice

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Exosomes derived from human umbilical cord mesenchymal stem cells alleviate acute liver failure by reducing the activity of the NLRP3 inflammasome in macrophages

Human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-EXOs) play an important role in the regulation of the immune system and inflammatory responses; however, their role in acute liver failure (ALF) and related pathological conditions is unclear. In this study, we found that hUCMSC-EXOs can reduce the expression of the NLRP3 inflammasome and downstream inflammatory factors in acute liver failure. Western blot and ELISA results showed that hUCMSC-EXOs decreased the expression of NLRP3, caspase-1, IL-1β and IL-6 in LPS-stimulated RAW 264.7 macrophages. In vivo, the hUCMSC-EXOs repaired damaged liver tissue and decreased the expression of the NLRP3 inflammasome and the levels of ALT and AST in a mouse ALF model. The results of this study provide a new strategy for the application of human umbilical cord mesenchymal stem cell-derived exosomes in the treatment of ALF.     

CS3抗原基因的表达及纤毛装配元件的研究

在肠毒素大肠杆菌(ETEC)的已知定居因子中,CS3是临床分离株中最常见的抗原之一。为了研究CS3纤毛装配的基本元件,绘制了CS3亚基结构基因和辅助蛋白编码区的限制酶谱。通过亚克隆的亚基基因和不同辅助蛋白基因之间的互补性表达结果,确定了CS3纤毛装配所需要的辅助蛋白的DNA功能片段。微细胞分析结果显示,CS3基因的有效表达和纤毛装配至少需要6条蛋白多肽,分子量分别为(×10~3)15、17、24、27、48和90。除了15×10~3/17×10~3的蛋白多肽为CS3亚基外,其余的蛋白多肽参与CS3亚基的转运及纤毛的装配。根据以上结果初步确定了上述相关基因的相对位置。