AFLP analysis revealed differences in genetic diversity of four natural populations of Manila clam(Ruditapes philippinarum) in China

1 IntroductionManila clam (Ruditapes philippinarum) is aworldwide distributed species. In China, it is foundfrom the northern to southern seashores (Wang etal., 1993; Zhuang, 2001). This species is eura-line with the salinity tolerance ranging from 20 to4…     

南沙海区中生界岩相分布及构造特征

为了了解南中国海南部南沙群岛陆架-陆坡区中生代地层发育情况,作者通过综合分析该海区钻井、拖网及1987年以来采集的20000多公里的多道反射地震勘探等资料,得到了对该区中生界基本特征的如下新认识:空间分布上,南沙的中生界具有从北部的郑和-礼乐隆起南缘向南增厚的趋势;沉积岩相方面,东部三叠纪时为深海相,侏罗纪为浅海与三角洲相,白垩纪为浅海-内浅海相,而往西南部中生代的海水深度有变深的趋势;中-新生代变形上,在南沙西部的曾母盆地,中生界褶皱为复式的、非协调性的,南沙中部多为舒缓褶皱,东部仅在近巴拉望海槽地带出现小幅度的褶皱。结合围区中生界及特提斯构造域的发育特征,作者提出南沙地块上的海相中生界在大地构造上归属于残留在中特提斯洋北部减薄陆缘地壳上的中特提斯期海相沉积地层,是该海域油气资源勘探不可忽视的对象。     

栉孔扇贝大量死亡的流行病学调查研究

2001~2003年,对养殖的栉孔扇贝进行了较系统地流行病学调查研究.以栉孔扇贝养殖集中海区长岛县亚美扇贝养殖场为定点调查和样品采集点.调查内容主要包括栉孔扇贝各养殖期的死亡率和可疑病原生物检测,同时对pH、溶解氧、温度、盐度等环境理化因子进行连续监测.调查结果显示:栉孔扇贝在养殖初期幼贝阶段死亡率较低,随后死亡率逐渐升高,至8月24日月死亡率达最高点71%.9月份以后死亡率开始下降.至10月份累积死亡率达90%以上.对环境理化因子的调查显示,pH、溶解氧、盐度的变化幅度不大,与扇贝死亡率无明显相关性;温度变化与死亡率似有一定的相关性,即高温(月平均23℃以上)可能是养殖栉孔扇贝重要的环境胁迫因子.通过对可疑致病性生物因子的调查研究及病理学观察表明,栉孔扇贝在养殖过程中可感染多种微生物,其中原核微生物类立克次体(RLO)在养殖过程各生长阶段均可检出,其感染率和感染强度与扇贝死亡率呈现一致的趋势.在病原病理检测中,发现RLO的大量感染与组织细胞严重病理损伤密切相关.在病原生物检测过程中,除RLO以外还发现有类枝原体原核生物(MLO)和类病毒(VLP)寄生.RLO的人工感染实验结果说明RLO是栉孔扇贝重要的病原菌.结合感染率和死亡率、感染强度和组织病理学的相关性以及感染实验的结果分析,认为类立克次体(RLO)可能是栉孔扇贝养殖过程中大量死亡的主要致病因子.     

热带太平洋深海微生物的若干生理生态特征

从2001年春、秋季于热带太平洋区采集到的深海样品中共分离到110株微生物,从中挑取31株进行形态特征和对环境理化因子适应特征的研究,同时利用Biolog微生物自动鉴定系统进行菌种鉴定和碳源代谢分析.结果表明:31株微生物中2株为酵母,21株为革兰氏阳性细菌,8株为革兰氏阴性细菌,来自底质的细菌菌株阳性菌占优势,而海水、蓝藻中阴性菌居多;温度、盐度、pH适应性试验表明,严格意义上的狭适性微生物不到总数的1/3,而具有较宽生态幅的广适性微生物占有相当大的比例.另一方面,耐冷菌、中度嗜盐菌和抗碱菌在这些微生物中的比例很高,同时,来自蓝藻的菌株大多数在4℃下不生长,而来自上覆水和底质的菌株可在4℃生长,这些都体现了微生物对生存环境的响应.31株微生物经Biolog鉴定12株得出鉴定结果.15株革兰氏阳性细菌对95种碳源的利用能力分析表明,不同菌株可利用碳源的数目从3种到46种不等,差异很大,体现了深海微生物营养类型的极大多样性;同时,发现有8种碳源可被一半以上的受试菌株所利用,这些碳源均是微生物各类代谢途径中的重要中间代谢物.     

Molecular cloning and expression analysis of interleukin-1β from Japanese sea perch (Lateolabrax japonicus)

1 Introduction IL-1βis a pleiotropic proinlammatory cytokine with a wide spectrum of inflammatory, metabolic, hematopoietic and immunological activities and is re- sponsible for the symptoms of sickness during the host response to infection (Dinarello, 1…     

Wave Reflection Caused by Wave Overtopping and Sloping Top of Spructure

In this paper, the theoretical analysis and experimental studies are employed to investigate the reflection characteris-tics of partial standing waves caused by wave overtopping and sloping top of structures. Based on the principle of conser-vation of wave energy flux, the third-order Stokes wave theory is used to formulate the reflection coefficient at wave overtopping; the calculation results are regressed into an applied expression. A series of experiments of wave reflection for a vertical-wall structure with chamfered and overhanging upper sections are carried out to investigate the influence of top slope on wave reflection. The regularity of variation of wave reflection in this case is analysed based on the experimental results.     

Coastal geomorphic evolution at the Denglou Cape, the Leizhou Peninsula

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温度、盐度、光照强度和pH对海洋原甲藻增长的效应

采用微量移液稀释法对海洋原甲藻进行无菌培养，以研究温度、盐度、光照强度和pH对海洋原甲藻增长的效应。结果表明，海洋原甲藻最大增殖速率发生在温度为(25±1)℃、盐度为31、光照强度为3000lx、pH为8.0的环境条件下。海洋原甲藻在温度18—28℃、盐度为25—34、光照强度为1000—6500lx、pH为7.5—8.3范围内适宜生长。这一结果与观测到的海洋原甲藻赤潮发生时环境条件相近，其中温度的效应最为明显。     

Biogeochemical Variation in Dimethylsulfide, Phytoplankton Pigments and Heterotrophic Bacterial Production in the Subarctic North Pacific during Summer

Dimethylsulfide (DMS), chlorophyll a (Chl-a), accessory pigments (fucoxanthin, peridinin and 19-hexanoyloxyfucoxanthin), and bacterial production (BP) were measured in the surface layer (0–100 m) of the subarctic North Pacific, including the Bering Sea, during summer (14 July–5 September, 1997). In surface sewater, the concentrations of DMS and Chl-a varied widely from 1.3 to 13.2 nM (5.1 ± 3.0 nM, mean ± S.D., n = 48) and from 0.1 to 2.4 µg L^–1 (0.6 ± 0.6 µg L^–1, n = 24), respectively. In the subarctic North Pacific, DMS to Chl-a ratios (DMS/Chl-a) were higher on the eastern side than the western side (p < 0.0001). Below the euphotic zone, DMS/Chl-a ratios were law and the correlation between DMS and Chl-a was relatively strong (r ² = 0.700, n = 27, p < 0.0001). In the euphotic zone, DMS/Chl-a ratios were higher and the correlation between DMS and Chl-a was weak (r ² = 0.128, n = 50, p = 0.01). The wide variation in DMS/Chl-a ratios would be at least partially explained by the geographic variation in the taxonomic composition of phytoplankton, because of the negative correlation between DMS/Chl-a and fucoxanthin-to-Chl-a ratios (Fuc/Chl-a) (r ² = 0.476, n = 26, p = 0.0001). Furthermore, there was a positive correlation between DMS and BP (r ² = 0.380, n = 19, p = 0.005). This suggests that BP did not represent DMS and dimethylsulfoniopropionate (DMSP) removal by bacterial consumption but rather DMSP degradation to DMS by bacterial enzyme.     

夏季珠江口沉积物中营养盐剖面分布和界面交换通量

通过对夏季珠江口区域沉积物间隙水营养盐剖面分析,调查了营养盐含量分布和特征,探讨了有机物的降解特性、营养盐的底部通量估算和作用.结果表明,珠江口沉积物间隙水中营养盐以高含量铵盐为主要的存在形式,沉积物中有机物的降解反应主要在厌氧状态下进行,底部水体铵盐的增加来源于底部沉积物有机质的降解释放,而且对水体的营养盐循环有较大的贡献.