厚壳贻贝(Mytilus coruscus)足丝蛋白mcofp3和mcofp6的cDNA克隆及序列分析

通过设计特异性引物,采用PCR扩增的方法对厚壳贻贝足腺细胞cDNA文库进行筛选,共克隆得到14条厚壳贻贝mcofp3的cDNA序列和8条mcofp6的cDNA序列,并对其基因序列及推导的氨基酸序列进行了序列比对和变异位点初步分析。结果表明,14条mcofp3cDNA序列分属于厚壳贻贝mcofp3家族的两个亚家族,其成熟肽序列变异相对活跃;而8条mcofp6 cDNA序列并无明显的亚家族划分,序列相对保守。本次实验所获得的mcofp cDNA序列初步显示了厚壳贻贝足丝蛋白家族基因的分子多样性,为将来深入了解厚壳贻贝足丝蛋白的分子多样性机制以及在此基础上开发相关的新型生物黏附剂奠定了基础。     

同种罗非鱼(Tilapia)不同地区选育群体的遗传多样性分析

采用微卫星标记分析技术,选用36对微卫星引物对罗非鱼原始群体和引种群体进行遗传多样性分析,原始群体为中国水产科学研究院淡水渔业研究中心保种的奥利亚罗非鱼("夏奥1号",ZA)、埃及尼罗罗非鱼("99品系",ZN),引种群体为广西水产研究所从淡水渔业研究中心引进培育的奥利亚罗非鱼群体(GA)和埃及尼罗罗非鱼群体(GN)。结果显示19对引物具备多态性,比率为52.8%,ZA与GA两个群体的平均观测杂合度、平均期望杂合度、平均多态信息含量分别为0.10、0.15、0.12,遗传相似性系数为0.9867,平均近交系数(FST)与基因流(Nm)分别为0.0379、6.3408;而ZN与GN两个群体平均观测杂合度、平均期望杂合度、平均多态信息含量分别为0.37、0.49、0.43,遗传相似性系数为0.7696,平均近交系数(FST)与基因流(Nm)分别为0.1146、1.9309。分析结果表明:(1)两个奥利亚群体中ZA与GA遗传多样性小,群体间遗传距离小,相似度较高,选育出的奥利亚群体遗传结构相对稳定;(2)两个尼罗群体中ZN与GN遗传多样性适中,群体间存在一定的遗传距离,相似度低,ZN与GN两个埃及尼罗群体具备进一步选育出新品系的潜力;(3)基因座UNH896、UNH995、UNH999可应用为鉴别奥利亚群体与埃及尼罗群体的特异性标记。     

南海北部冬季和夏季浮游哲水蚤类群落

根据2004年2月10日-3月6日(冬季)和8月26日-9月6日(夏季)在南海北部的两个航次中用浮游动物大网垂直拖网采集的浮游动物样品,对该海域的浮游桡足类群落进行分析。结果表明,共发现哲水蚤类70种,冬季航次62种,夏季航次62种,种类的季节变化不大。在海洋站位,每个站位出现的哲水蚤类为4-41种,近岸的站位出现的种数少,向远海逐渐增多。哲水蚤总丰度冬季为10-353个/m3,夏季为13-205个/m3,从近岸到远海减少。哲水蚤生物量干重冬季为0.80-33.39mg/m3,夏季为0.64-5.81mg/m3,从近岸到远海减少。种类多样性指数采用香农-威弗指数,冬季为0.80-4.39,夏季为2.12-4.66,在近岸较低,远海较大。优势度大于2%的种被认为是优势种。冬季的优势种为:中华哲水蚤(Calanus sinicus)、小拟哲水蚤(Paracalanus parvus)、狭额真哲水蚤(Subeucalanus subtenuis)、弓角基齿水蚤(Clausocalanus arcuicornis)、长尾基齿水蚤(Clausocalanus furcatus)、达氏波水蚤(Cosmocalanus darwini)。夏季的优势种(类)为:微刺哲水蚤(Canthocalanus pauper)、小哲水蚤(Nannocalanus minor)、狭额真哲水蚤、亚强真哲水蚤(Subeucalanus subcrassus)、小拟哲水蚤、锥形宽水蚤(Temora turbinata)、柱形宽水蚤(T.stylifera)、异尾宽水蚤(T.discaudata)。这些种在各个站位占总丰度的15%-92%(平均为48%)。优势度大于5%的种有中华哲水蚤、小拟哲水蚤、狭额真哲水蚤、锥形宽水蚤、异尾宽水蚤,各种的丰度(除狭额真哲水蚤外)从近岸向远海降低。在远海深水的站位,出现了热带暖水种乳点水蚤属的腹突乳点水蚤(Pleuromamma abdominalis)、瘦乳点水蚤(P.gracilis)和粗乳点水蚤(P.robusta)。哲水蚤目种丰富度、桡足类丰度、多样性指数、优势种丰度从近岸到远海的变化趋势,反映了桡足类群落从近岸到远海的演替。     

Seasonal variations of phytoplankton diversity in the Coleroon coastal waters, southeast coast of India

The results of an investigation carried out during June 2005 to May 2007 on physico-chemical parameters,species composition and community structure of phytoplankton including Chlorophyll a(Chl-a) at the Coleroon coastal waters(Southeast coast of India) are reported.Air and surface water temperatures(°C) varied from 25.1 to 30.1 and from 24.5 to 28.5 respectively.Salinity values varied from 6 to 28.5 and the pH ranged between 7.0 and 8.3.Variation in dissolved oxygen content was from 3.1 to 7.5 mg/dm-3 while the light extinction coefficient values(LEC) ranged between 3.1 and 10.1 cm.The ranges of inorganic nutrients(μmol/dm-3) viz.,nitrate,nitrite,phosphate and silicate were 10.1-23.4,1.2-8.9,0.2-3.1 and 55-125,respectively.The ranges of Chlorophyll a(μg/dm-3) values was 2.0-7.5.Presently,124 phytoplankton species representing different classes viz:Bacillariophyceae(77),Dinophyceae(19),Cyanophyceae(15),Chlorophyceae(10) and Chrysophyceae(3) were recorded.The phytoplankton cell abundance varied from 0.290 to 111.662 cells/cm-3,with peak diversity(3.38 bits/ind.) during summer season.The maximum abundance was found during summer season coinciding with the stable hydrographical conditions.The seasonal distribution and abundance of phytoplankton are discussed in relation to hydrographical parameters.Canonical Correspondence Analysis(CCA) was applied in this paper for discriminating environmental factors having effect on phytoplankton community at species level.Coleroon coastal water is subjected to long term fluctuations in physico-chemical parameters depending upon the seasonal tidal amplitude and freshwater influx resulting in a continuous exchange of organic,inorganic,plant and animal matters.     

黄渤海松江鲈鱼线粒体控制区结构与序列多态性分析

测定了辽宁丹东、盘锦与河北秦皇岛35尾松江鲈鱼线粒体控制区序列977bp。共检出单倍型30个,多态位点35个,简约信息位点27个,绝大多数变异集中在192-342bp、594-783bp区段,同时识别出了线粒体控制区5’端终止序列区、中央保守区和3’端保守序列区的关键序列。3个群体总的单倍型多样性为0.990,核苷酸多样性为0.00718,丹东群体核苷酸多样性最高(0.00959)。群体间、群体内平均遗传距离低(分别为0.0067和0.0063);在NJ树上不同地理来源的个体混杂分布;Fst分析显示丹东与秦皇岛群体间遗传分化相对较大(0.14222,p0.05),其余不明显(0.02865-0.05616,p0.1),表明3个群体有可能隶属同一个种群。核苷酸不配对分布图表明松江鲈鱼可能未经历过大规模的种群扩张。     

胶州湾中部海域秋、冬季大型无脊椎动物群落结构及多样性研究

根据2008年9月~2009年2月在胶州湾中部海域进行的逐月定点底拖网调查,对该海域秋、冬季大型无脊椎动物群落结构及多样性变化进行了初步研究.结果表明,胶州湾秋、冬季共捕获大型无脊椎动物60种,其中甲壳动物和软体动物是主要的无脊椎动物类群;优势种组成具有较明显的月间变化,主要为口虾蛄Oratosquilla oratoria、短蛸Octopus ocellatus、脊腹褐虾Crangon affinis等湾内定居性种类及洄游性较小的种类.Margalef种类丰富度指数范围为1.998~4.669,自9月起逐月递减,11月达到最低值,随后又逐月升高,2月达到最高值;Shannon-Wiener多样性指数和Pielou均匀度指数范围分别为1.325~2.500和0.422~0.693,逐月变化趋势与物种丰富度指数基本一致.多样性指数与海域温度、盐度和深度等环境因子均无显著性相关.多元统计分析表明,胶州湾中部海域秋、冬季大型无脊椎动物群落可划分为2个时间组群;组群间群落种类组成结构差异不显著.     

从“坚守”到“严守”——写在第19个全国土地日

实验证明,在没有任何干扰的情况下,再生25毫米的土表需要300年时间.这种再生速度对于迅速耗蚀的土地并没有多少补偿作用.     

近江牡蛎两个野生种群的遗传多样性分析

采用RAPD分子标记和rDNA-ITS1序列分析了近江牡蛎Crassostrea rivularis湛江官渡和阳江程村野生种群的遗传多样性。12个RAPD引物共扩增出8838条片段,157个位点,平均每个引物可产生13个位点,片段长度在200～2200bp之间。湛江种群和阳江种群的多态位点比例分别为89.62%和89.57%,遗传多样性指数分别为0.4170和0.4334。种群间平均遗传距离为0.0327,平均遗传相似性为0.9681,平均遗传分化系数为0.0437。得到近江牡蛎18S、5.8S部分序列和ITS1全部序列,其中ITS1序列片段长度为478～485bp,共有11个变异位点,两个为转换(A/G),其他为插入/缺失(A/-、T/-)。湛江和阳江种群各获得8个单倍型,其中有一个单倍型为两个种群共享。两个种群的CG碱基平均含量较高,分别为58.29%和58.41%。种群间的遗传分化系数0.0254。结果说明,近江牡蛎湛江种群和阳江种群间具有较高的遗传多样性和较低的遗传分化。     

人工育珠对三角帆蚌(Hyriopsis cumingii)遗传基因影响的初步研究

采用酚-氯仿和试剂盒两种提取法对三角帆蚌怀珠群与非怀珠群各6个个体进行基因组DNA的提取,然后在优化RAPD(随机扩增多态性DNA)检测条件基础上,从80个随机引物中筛选出12个扩增较好且多态性强的引物进行RAPD扩增,产物通过水平板琼脂糖凝胶电泳和垂直板聚丙烯酰胺凝胶电泳两种方法进行检验并对DNA的多态性进行分析。结果显示在怀珠群和非怀珠群检测到的位点数、多态位点比例、平均Shannon多态性信息指数、平均Nei's基因多样性指数、群体内个体间平均遗传相似率和平均遗传距离分别为100、33%、0.1927、0.1324、0.904、0.096,95、47.37%、0.2711、0.1879、0.861、0.139,群体间的平均遗传距离为0.821,非怀珠群的变异性大于怀珠群;本研究还获得了两群体各自的特异扩增谱带及两群体间表达差异较大谱带,这些位点很可能是由人工育珠所引起。根据MEGA4.0软件的UPGMA和NJ程序构建的分子系统树可直观地将两群体分开。     

Growth of marine bacteria and ammonium regeneration from substrates in different C: N ratios

Natural assemblages of marine bacteria were chosen in a batch culture experiments. The impact of varying nitrogen substrate concentrations and the substrate C:N ratios (C:N_S) on the bacterial C:N ratio (C:N_B), the bacterial growth efficiency (BGE) and ammonium regeneration was mainly examined. The C:N_S ratios varied from 5:1 (carbon limitation) to 40:1 (nitrogen limitation) with varying combinations of glucose and NO₃^-. The C:N_B ratio had positive relationship with the C:N_S ratio (r=0.93, n=8), whose value was 3.77 when the C:N_S ratio was 5:1 but increased to 6.47 when the C:NS ratio was 40:1. These results indicate that the C:N_B ratio is a potential diagnostic tool for determining the bacterial growth in natural waters controlled by either, carbon or nitrogen. BGE decreased with the declining nitrate concentration and negatively related to C:N_s (r=-0.51, n=8). The average value of BGE was 0.20. This value was a little lower than other reports, which could be induced by the nitrogen source used in our experiments. Finally, regeneration time of ammonium delayed with the increasing C:N_S ratio, which indicates that there were different metabolism mechanisms when bacterial growth was limited by carbon source and nitrogen source.