半叶马尾藻多糖对γ射线氧化损伤小鼠的保护作用

采用检测小鼠血浆和肝脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和丙二醛(MDA)的方法，观察半叶马尾藻多糖[Sargassum hemiphyllum(Turner)C．Ag．polysaccharides，sHP]对2Gy γ射线损伤小鼠氧化自由基的影响。结果发现20mg／kg和40mg／kg的SHP不仅能明显降低辐射损伤小鼠血清和肝脏的MDA含量，而且能够提高辐射损伤小鼠SOD和CAT的活性，并呈剂量依赖性增强。10mg／kg的SHP对辐射损伤小鼠肝脏SOD、小鼠血浆和肝脏CAT也有明显的促进作用。提示半叶马尾藻多糖具有清除γ射线所致自由基和抑制脂质过氧化的作用。     

紫菜腐霉侵染对条斑紫菜叶状体防御性物质含量及保护性酶类活性的影响

研究了紫菜腐霉侵染对条斑紫菜叶状体防御性物质脯氨酸(Pro),保护性酶类苯丙氨酸转氨酶(PAL)、多酚氧化酶(PPO),防御信号活性氧(ROS)和细胞损伤指示性物质丙二醛(MDA),在不同时间点(0、1、3、5、7、9d)的含量和活性影响。实验结果表明:紫菜腐霉侵染能够打破细胞ROS的动态平衡,引起ROS含量极显著增加(P0.01),进而影响细胞渗透压平衡,表现为Pro含量极显著增加(P0.01),并导致细胞内保护酶类PAL和PPO活性极显著增加(P0.01),并且ROS积累引起细胞膜脂过氧化,MDA含量发生极显著变化(P0.01)。由此推测条斑紫菜叶状体对紫菜腐霉侵染的生理响应过程为:紫菜腐霉侵染引起藻体ROS含量积累上升,积累的ROS激活机体防御系统,Pro含量增加以调节细胞渗透平衡;同时积累的ROS激活细胞内保护酶类,PAL和PPO的活性增强。迅速积累的ROS引起细胞损伤,导致细胞膜脂过氧化,产生并积累MDA。本实验为全面了解条斑紫菜防御紫菜腐霉侵染的机制奠定了基础,同时为后续条斑紫菜赤腐病抗性品系的选育提供了理论指导。     

羽藻叶绿体膜的纯化与多肽的初步研究

细胞膜系统,是细胞许多生命现象如收缩运动、信息传递、物质运输等的场所和调节关键部位。七十年代首先在红细胞发现了膜骨架。八十年代大多数红细胞膜蛋白已经提纯,其功能亦已清楚。在植物中,Palevitz等(1974年)在Nitella细胞中观察到肌动     

外源一氧化氮和金属铜对海洋微藻抗氧化系统的影响

以亚心形扁藻为研究对象,通过添加不同浓度一氧化氮(NO)(1.4×10-10～1.4×10-5 mol/L)培养,探讨NO对微藻生长、H2O2和MDA含量以及SOD活性的影响;通过对只添加金属Cu、同时添加Cu与NO实验,对微藻的H2O2和MDA含量以及SOD活性的影响进行了对比研究。结果表明,藻细胞活性氧的代谢有随NO浓度增加的趋势,同时细胞内的抗氧化酶SOD活性和MDA含量都有相应的变化,NO作为环境的"刺激物"提高了细胞内的活性氧水平,对抗氧化系统起到激活或伤害作用。在Cu胁迫下,藻细胞活性氧代谢明显提高,SOD活性提高,并导致细胞膜脂过氧化;但外源NO能明显降低活性氧的水平,并恢复SOD活性和MDA含量,对抗氧化系统起到保护作用,提高微藻的抗氧化能力。研究表明,NO在海洋浮游植物中扮演着"双重角色"——氧化剂和抗氧化剂,从而对微藻的生长起到重要的调节作用。     

多氯联苯(Aroclor 1242)胁迫下鲤鱼肝脏组织氧化应激

本文在实验室条件下通过静态水质染毒方式在生理生化和转录水平上探究了我国重要经济鱼种鲤鱼(Cyprinus carpioio)对多氯联苯Aroclor 1242的氧化应激:鲤鱼肝脏组织抗氧化酶[超氧化物歧化酶(SuperoxideDismutase,SOD)和过氧化氢酶(Catalase,CAT)]活性、脂质过氧化产物丙二醛(Malonydialdehyde,MDA)含量、相关抗氧化酶编码基因(Cu/Zn-SOD、Mn-SOD、CAT)、应激蛋白HSP70、转录因子Nrf2和芳烃受体AhR2基因表达。结果表明:Aroclor 1242胁迫下,鲤鱼肝脏组织抗氧化酶活性表现出低浓度促进高浓度抑制的趋势;肝脏组织丙二醛含量显著升高,其中390μg/L暴露组鲤鱼肝脏组织MDA含量在第6d高于对照组92.1%(P0.01),表明肝脏组织发生脂质过氧化,膜系统受到损伤;鲤鱼肝脏组织中Cu/Zn-SOD、Mn-SOD、CAT、HSP70、Nrf2和AhR2编码基因表达出现不同程度下调。本文从酶学和基因转录水平上揭示了Aroclor1242胁迫下鲤鱼肝脏组织细胞的氧化应激。     

不同盐胁迫时间下秋茄幼苗叶片膜脂过氧化作用的研究

对长时间和短时间盐胁迫下红树植物秋茄(Kandelin candel)叶片膜脂过氧化作用、叶绿素含量、电解质渗透率、叶片肉质化程度等与盐胁迫强度之间的关系进行了对比研究.结果表明,短时间盐胁迫和长时间盐胁迫下秋茄叶片超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、叶片肉质化程度等随盐胁迫强度的提高而有不同的变化规律.在短时间盐胁迫下,随基质盐度的提高,SOD活性(fw)变化呈“U”型,在盐度15～20处叶片SOD活性最低,MDA含量变化不明显,电解质渗透率和叶片肉质化程度先升高而后下降,在盐度20处最高;在长时间盐胁迫下,SOD活性先随盐度的提高而提高,当盐度高于10时又随盐度的提高而下降,而MDA含量随盐胁迫程度的提高而下降,电解质渗透率和肉质化程度却上升,不同盐胁迫时间下红树植物秋茄具有不同的耐盐机制.膜脂过氧化不是盐胁迫下秋茄叶片膜损伤的主要原因.     

EGb761对视神经损伤后视神经节细胞自噬的影响

目的：观察银杏提取物EGb761对大鼠视神经损伤后视网膜神经节细胞自噬活性及自噬流的影响,并探讨其作用机制。方法：将48只SD大鼠随机分为EGb761组和对照组,分别给予EGb761（150mg/kg·d）和0.9%氯化钠注射液灌胃,均每天1次,直到处死。分别于损伤后第7天、第14天取材,采用免疫组化检测2组视网膜神经节细胞自噬相关蛋白LC3B、自噬标记蛋白p62及自噬基因Beclin-1及mTOR通路蛋白p-mTOR、p-S6表达水平,腺病毒GFP-mRFP-LC3荧光瞬时转染技术检测自噬流表达。结果：与对照组相比,EGb761组LC3B表达水平升高,p62、p-mTOR和p-S6蛋白表达水平均下降（均P<0.05）;2组Beclin-1差异无统计学意义（P＞0.05）;2组GFP和mRFP荧光点数比较,EGb761组的红点多于对照组,黄点少于对照组（均P<0.05）。结论：EGb761能够促进大鼠视神经损伤后视网膜神经节细胞自噬流,其机制可能与促进mTOR信号通路中的相关蛋白表达有关。     

球形棕囊藻溶血毒素对兔红细胞作用的AFM观察

溶血性毒素是有毒藻类分泌较多的一类毒素,具有溶血活性。运用光学显微镜和原子力显微镜(AFM)观察了球形棕囊藻Phaeocystis globosa溶血毒素对兔红细胞的溶血现象。结果显示,经毒素处理后的兔血红细胞边缘凹凸不平,只剩下一小部分残骸。该毒素可能由于其双亲性质与血红细胞膜表面的膜脂连接,产生脂溶效应,使细胞膜破坏。     

大菱鲆卵子排放后在卵巢腔内老化特征初探

为了探明大菱鲆(Scophthalmus maximus)卵子在卵巢腔内老化的原因及特征,采用连续跟踪采卵的方式,通过荧光染色、生理生化指标测定,对不同采卵时间(0, 3, 6, 9, 12 h)的卵子活性氧和脂质过氧化情况(氧化产物丙二醛MDA)、抗氧化系统(超氧化物歧化酶SOD,还原型谷胱甘肽GSH)、卵巢液pH值及受精率和孵化率进行对比研究。结果表明,随着卵子在体内老化时间的延长,其活性氧含量及脂质过氧化程度逐渐升高,活性氧含量及过氧化程度与排卵后卵子老化呈正相关;SOD酶活力,GSH酶活力均显著下降,MDA含量显著提高;受精率和孵化率均显著下降。排卵后6h,孵化率降到2.87%～10.60%,此时的卵质已经极度恶化,不能再继续用于后续的生产中。综上,在卵巢腔中,卵子排放后,随着时间的延长,活性氧含量显著升高,抗氧化能力逐渐下降,受精率和孵化率显著降低,老化逐渐加剧。     

高温对褐藻羊栖菜逆境生理的影响

分别在27℃和32℃高温条件下培养羊栖菜(Sargassum fusiforme), 以在22℃培养条件下生长的羊栖菜作为对照, 在培养的第0、1、3、5和7天分别取气囊样品, 采用植物生理学试验方法探讨高温胁迫对羊栖菜细胞膜损伤、渗透调节和抗氧化保护的影响。结果表明: 1) 高温胁迫导致羊栖菜细胞的相对电导率提高和丙二醛(MDA)质量摩尔浓度增加, 膜系统受到了损伤, 造成体内离子外渗、细胞膜脂发生过氧化; 2) 细胞内积累了可溶性蛋白、可溶性糖和脯氨酸等渗透调节物质并且胁迫组始终高于对照组, 其中可溶性蛋白在胁迫第7天时达到最大值(11.4μg·mg^-1), 而可溶性糖和脯氨酸均呈现先升高后降低的趋势, 分别在高温培养的第3天和第5天时达到最大值; 3) 受到高温胁迫后, 羊栖菜超氧化物歧化酶(SOD)比活性增强, 而过氧化物酶(POD)和过氧化氢酶(CAT)比活性在高温胁迫过程中呈现下降的趋势, 说明羊栖菜主要通过抗氧化酶SOD比活性增强来降低胁迫对藻体带来的伤害。总之, 羊栖菜对高温胁迫比较敏感, 温度越高, 培养时间越长, 羊栖菜受到的伤害越大。     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.     

A Tidal Flow Model for the Gulf of Kachchh, India

A vertically integrated model has been used to study the tidal circulation and currents in the Gulf of Kachchh along the west coast of India. The model is fully nonlinear and uses a semiexplicit finite difference scheme to solve the basic hydrodynamic equations on a staggered grid. The model is forced by prescribing the tides along the open boundary of the model domain. The flow is simulated both with and without the presence of the proposed tidal barrage across the Hansthal Creek in the Gulf of Kachchh. The results show a considerable change in the behavior of the tidal flow in the presence of the barrage.     

利用中国GF-3卫星SAR和HY-2A卫星微波散射计的首次台风联合定量观测

<正>The typhoon,as a mature tropical cyclone that develops in the western part of the North Pacific Ocean with high wind speed and heavy rainfall,is one of the most lethal and costly of natural disasters for the densely populated countries of East Asia.It can be easily detected by space-borne sensors operated at microwave,visible or infrared bands(Liu et al.,2014).Synthetic Aperture Radar(SAR)is     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

离子交换—原子吸收光谱法测定海水中痕量铜、铅、锌、镉、铁、锰

本文介绍了用国产D401型螯合树脂分离富集海水中铜、铅、锌、镉、铁、锰等痕量元素,并用原子吸收光谱仪测定其含量的方法。讨论了各元素的分离条件选择及干扰元素的影响,并与溶剂萃取法的结果作了比较。各元素检测的定量下限为:铜0.5μg/L、铅0.1μg/L、锌1.0μg/L、镉0.01μg/L、铁2.0μg/L、锰2.0μg/L。方法精密度在4—8％之间,回收率为90—102％。