简介:首先采用饱和硫酸氨分步沉淀和SephadexG-200凝胶层析的方法,获得了非免疫状态下中华鲟(AcipensersinensisGray)和达氏鳇(HusodauricusGeorgi)的血清免疫球蛋白(Ig),在此基础上使用木瓜蛋白酶水解对所获得的免疫球蛋白片段进行了酶解,并采用SDS-PAGE和Western-blot等方法分析了所获得的水解片段。结果显示,2种鲟鱼的免疫球蛋白均可被木瓜蛋白酶水解蛋白,通过SephadexG-100凝胶层析后均可得到两个完全分离的、均一的蛋白峰。SDS-PAGE检测两个水解片段的相对分子量分别为44KD和66KD,West-ern-blot检测结果显示,66KD的片段可以在硝酸纤维素杂交膜上被各自的兔抗鲟IgM多克隆抗体所识别,而44KD片段的检测结果为阴性。这表明,2种鲟科鱼类的木瓜蛋白酶水解特性相同,提示鲟科鱼类的免疫球蛋白在免疫学及生化方面具有较大的相似性。
简介:从建构主义视角分析蓬莱19-3溢油事件,并不是否认它是“有问题的”的客观事实,而是要揭示它是如何“问题化”的,即如何由“问题”演变为“社会问题”。溢油事件发生后,一直存在着多种社会力量的角逐。从它“浮出水面”到“问题化”的过程中,政府、科学家、大众传媒、社会公众和渔民分别以不同的方式对这一客观事实进行建构。蓬莱19-3溢油事件“问题化”过程研究表明:它成为一个社会问题,是社会界定和话语分析的结果;同时,社会结构的变化对蓬莱19-3溢油事件的“问题化”产生着深刻影响。溢油事件中的社会建构机制和信息发布机制,对于政府部门处置类似环境突发事件具有重要借鉴意义。
简介:Background:Withinthehighlybio-diverse‘NorthernVietnamLowlandRainForestsEcoregion'onlysmall,andmostlyhighlymodifiedforestlandspersistwithinvastexotic-speciesplantations.Theaimofthisstudywastoelucidatevegetationpatternsofasecondaryhillsiderainforestremnant(elevation120–330m,76ha)asanoutcomeofnaturalprocesses,andanthropogenicprocesseslinkedtochangingforestvalues.Methods:Intherainforestremnanttreespeciesandvariousbio-physicalparameters(relatingtosoilsandterrain)weresurveyedonforty20m×20msizedplots.Theforest'svegetationpatternsandtreediversitywereanalysedusingdendrograms,canonicalcorrespondenceanalysis,andotherstatisticaltools.Results:Foresttreespeciesrichnesswashigh(172inthesurvey,94perhectare),includingmanyendemicspecies(>16%;somerecentlydescribed).Vegetationpatternsanddiversitywerelargelyexplainedbytopography,withcolline/sub-montanespeciespresentmainlyalonghillsideridges,andlowland/humid-tropicalspeciespredominantonlowerslopes.Scarcityofhigh-valuetimberspeciesreflectedpastlogging,whereasabundanceoflight-demandingspecies,andspeciesvaluedforfruits,providedevidenceofhuman-aidedforestrestorationand‘enrichment'intermsofusefultrees.Exhaustionofsought-afterforestproducts,anddecreasingappreciationofnon-woodproductsconcurredwithfurtherencroachmentofexoticplantationsinbetween2010and2015.Regenerationofraretreespecieswasreducedprobablyduetoforestisolation.Conclusions:Despitelong-termanthropogenicinfluences,remnantforestsinthelowlandsofVietnamcanharborhighplantbiodiversity,includingmanyendangeredspecies.Varioussuccessivefuturechanges(vanishingspecies,generalistdominance,andassociatedforeststructural-qualitativechanges)are,however,expectedtooccurinsmalforestfragments.Lowlandforestbiodiversitycanonlybemaintainedifforestfragmentsmaintainacertainsizeand/orareconnect