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1.
镉对褐菖You金属结合蛋白的诱导 总被引：1，自引：1，他引：1
金属结合蛋白是一类富含半胱氨酸，不含芳香族氨基本以和组氨酸的低分子量蛋白质。在紫外２５４ｎｍ处具强的吸收。用不同剂量的氯化诱导褐菖Ｙｏｕ，通过凝胶过滤从褐菖Ｙｏｕ肝脏提取金属结合蛋白，并测定其结合的镉以及硫醇含量与紫外２５４ｎｍ处的吸收值。结果表明，镉能诱导褐菖Ｙｏｕ金属结合蛋白的合成。 相似文献
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重金属对扁额细首纽虫金属硫蛋白的影响 总被引：1，自引：0，他引：1
生物体内金属硫蛋白含量变化,可作为环境中重金属污染的生物标志物.通过暴露实验研究了扁额细首纽虫Cephalothrix simula暴露在不同浓度的铜,锌和镉溶液96 h,其体内金属硫蛋白含量的变化规律.结果表明3种重金属离子的胁迫作用均导致金属硫蛋白含量增加,在实验初期(6～24 h),金属硫蛋白含量达到高峰;金属硫蛋白含量与暴露溶液金属浓度具有明显的剂量～效应关系,金属离子浓度越高,金属硫蛋白含量越高;锌离子诱导金属硫蛋白合成的作用大于铜、镉离子. 相似文献
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探讨了秋茄叶中黄酮类物质的极谱特性,并进行了含量测定.结果表明,在pH值为9.18的硼砂底液中,以芦丁作对照品,秋茄叶中黄酮类化合物在峰电位Ep为-1 642 mV（vs.SCE）处产生一灵敏的二阶导数极谱波,在芦丁含量不超过1.4 mg/dm3范围内,该极谱波的峰电流（Ip）与芦丁的量之间呈良好的线性关系,据此建立了红树秋茄叶中总黄酮含量的极谱定量测定方法.该方法的检出限为0.02 mg/dm3.用此法测得红树秋茄叶中总黄酮含量为2.04%,回收率为96.4%～100.3%,相对标准偏差为3.19%,此方法灵敏、准确、干扰少. 相似文献
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微量金属在天然水中的含量及分布,颇引人注目。这是由于人们已证实,许多必须的微量金属,在生物体中起着十分重要的作用。作为千百种酶的活性核心和激活因子,它们参予各种代谢过程,这些金属与蛋白质、脂肪、维生素不同,不能由机体合成,而必须从食物和水中获得。至于非必须的微量金属,例如镉会污染环境,造成公害。有机体在吸取必须的微量金属同时,也吸取了非必须的微量金属镉。自然界中镉以硫化镉的简单形式存在,通常同锌、铅矿缔合,在矿区和冶炼区的粘土中,镉的累集可能产生附近水里的局部高浓度。多数淡水镉浓度低于1μg/L,而多数海水分析指出,镉的平均浓度大约为0.15μg/L。 相似文献
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为了利用双壳类动物金属硫蛋白(MTs)指示海洋重金属污染,有必要确定有效提取这种生物标志物的方法。本研究以暴露于含镉海水的菲律宾蛤仔内脏为试验材料,依次采用正交设计和单因素设计对内脏MT(以粗提液中的巯基含量表示)的提取工艺条件进行优化。所得到的最佳匀浆条件为:Tris-HCl缓冲液浓度为0.02 mol/L,pH值7.8,内脏与缓冲液的质量体积比(m/v)为1/5,其中,缓冲液的浓度对提取效果影响较大。最佳除杂条件为:匀浆液首先在4℃、20 000 g离心30 min,再于80℃水浴加热10 min,然后于4℃15 000 g离心10 min。这些结果有助于重金属生物监测中蛤仔MT的经济高效提取和共存杂蛋白干扰的有效去除。 相似文献
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锯缘青蟹NAGase在DMSO溶液中的失活动力学 总被引：3，自引：1，他引：3
以二甲亚砜（DMSO）为效应物，研究其对锯缘青蟹N-乙酰-β-D-氨基葡萄糖苷酶（NAGase）活力的影响，结果表明，酶的剩余活力随着DMSO浓度增高而迅速下降，当DMSO浓度达4．0moL／dm^3时，酶活力几乎完全丧失，该酶在低于2mol／dm^3的DMSO溶液中的失活作用表现为可逆过程，导致酶活力丧失50％的DMSO浓度（IC50）为0．75mol／dm^3应用酶失活过程的底物反应动力学方法测定了游离酶（E）和酶-底物络合物（ES）在不同浓度DMSO溶液中的微观失活速度常数k＋0和k’＋0，k＋0明显大于k’＋0，说明游离酶较酶-底物络合物对DMSO更为敏感，底物对酶被DMSO失活有保护作用．随着DMSO浓度增加，逆向微观复活速度常数k-0不断下降，这说明NAGase在高浓度DMSO中失活的可逆性减弱。 相似文献
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海洋动物金属硫蛋白的提取与分析技术研究进展 总被引：2，自引：0，他引：2
金属硫蛋白(metallothioneins,MTs)是一类低分子量、富含半胱氨酸的金属结合蛋白。由于水生生物体的MTs能被金属诱导,而且诱导程度与水环境重金属浓度之间存在一定的相关性,可间接反映出水环境中重金属的污染水平,因此,海洋动物体内的MTs已被认为是海水和沉积物重金属污染的生物标志物。近20 a来,为了将MTs应用于海洋污染的生物监测,国内外学者先后研究了多种分析技术及相应的提取方法。本文对目前已报道的海洋动物MTs提取与检测技术进行了评述,并根据存在的不足提出了今后的研究重点。 相似文献
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钝顶螺旋藻藻胆蛋白的提取及其特征初报 总被引：3，自引：0，他引：3
作者采用细胞破碎，等电点沉淀的方法，提取、分离螺旋藻的藻胆蛋白，并在藻胆蛋白中检测到１７种氨基酸。文中还研究了在５００－７００ｎｍ波长范围内不同外界因子对藻胆蛋白理化特性的影响，结果表明：（１）不同的ｐＨ值，藻胆蛋白液颜色及吸收光谱的形状和强度不同。当ｐＨ为４和５．５时，藻胆蛋白液呈绿蓝色，吸收峰在６２５ｎｍ处，而ｐＨ为７，吸收峰移至６００ｎｍ。（２）藻胆蛋白热稳定性差，吸收光谱强度随着温度升高而 相似文献
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本文基于南大洋环流研究最新资料，从资料来源、动力模式以及有待解决的问题几个方面较详细地阐述南大洋环流动力学研究动态。 相似文献
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长江口外赤潮多发区近几十年来的古生产力记录及环境意义 总被引：5，自引：3，他引：2
选取长江口外赤潮多发区沉积物柱状样,在高分辨率测年基础上,通过有机碳、有机碳同位素(δ13C)、生物硅、绿素等多项指标的分析获得了调查海区古生产力的变化信息。并结合近几十年来营养盐浓度及组成结构的变化探讨了海洋浮游藻类组成结构的变化在海洋古环境中的记录。柱状样年代可追溯到20世纪40年代初。δ13C值在柱中的分布为-26.15×10-3~-19.5×10-3,表明有机碳为陆源与海生的混合。生物标志物在柱状样中的分布可大致分为三个阶段,50年代以前含量均较低;50年代至80年代含量均增加,表明海洋浮游藻类活动强烈且以硅藻为主,与此阶段长江口营养盐浓度迅速增加相对应;80年代以后,生物硅的含量下降至整个柱中最低水平,绿素有所降低,但高于50年代前的水平,而有机碳含量增加,表明在该时段硅藻生物量降低,其他藻类生物量有所增加,这与长江口营养盐氮盐持续增加而硅酸盐逐年降低、氮与磷的含量比值、磷与硅的含量比值迅速增大有关。沉积记录还表明此阶段陆源有机碳的贡献增强。 相似文献
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K. V. Ushakov T. B. Grankina R. A. Ibraev 《Izvestiya Atmospheric and Oceanic Physics》2016,52(4):365-375
A numerical experiment on the reproduction of the variability in the state of North Atlantic water in 1948–2007 with a spatial resolution of 0.25° has been performed using the global ocean model developed at Institute of Numerical Mathematics, Russian Academy of Sciences (INM RAS), and the Shirshov Institute of Oceanology (IO RAS) (the INM–IO model). The data on the state of the atmosphere, radiation fluxes, and bulk formulas of the CORE-II protocol are used as boundary conditions. Five successive 60-year calculation cycles have been performed in order to obtain the quasi-equilibrium state of a model ocean. For the last 20 years, the main elements of large-scale ocean circulation have been analyzed and compared with the WOA09 atlas data and the results of other models. 相似文献
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This paper analyses the global tendency of the sea level rise (SLR) and its long term influence on the sea level upstream drainage cascade based on the example of the level’s variation in the Vistula Lagoon of the Baltic Sea compared to the other lagoons and coastal regions of the southeastern part of the Baltic Sea. A steady positive trend in the water level variations was revealed; its magnitude varies significantly depending on the time period. In general, during the 100–150 year period, the rate of the SLR in the lagoons and coastal areas of the Baltic Sea (1.7–1.8 mm per year) is close to the SLR rate in the World Ocean. In the second half of the 20th century, the increased rate of the SLR in the lagoons and marine areas became stronger (up to 3.6 mm per year in the Vistula Lagoon and in 1959–2006 in the sea and exceeded the rate of global ocean SLR). It dramatically increased at the end of the last century both in the lagoons and in the sea (up to 10.0–15.0 mm per year). This is the response not only to the global climate warming but it is likely that it is also a response to the changes of the climate driving forces that influence the regimes of the local wind and precipitation in the catchment. 相似文献
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The Moho transition zone in the Oman ophiolite-relation with wehrlites in the crust and dunites in the mantle 总被引：1，自引：0，他引：1
Field data in the Oman ophiolite show that the Moho transition zone (MTZ), which is on average 300 m thick above mantle diapirs, reduces to 50 m away from diapirs, with a sharp transition at the outskirts of the diapirs. We show here that this reduction is dominantly due to compaction of a dunitic mush present above diapirs in the MTZ, with upward injection of a wehrlitic magma in the crust, and, to a lesser extent, due to tectonic stretching. In order to explain the fraction of wehrlites injected into the crust, which is in the range of 25%, it is necessary that mantle upwelling is active, with a mantle flow velocity away from diapirs several times faster than the spreading velocity. If this velocity exceeds 5 times the ridge spreading-rate, a significant part of the MTZ may be entrained down into the mantle, flowing away from the diapir as tabular dunites. 相似文献
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Distribution of Pacific-origin water in the region of the Chukchi Plateau in the Arctic Ocean in the summer of 2003 总被引：6，自引：1，他引：6
1Introduction Besidestheprecipitationandriverdischarges,the watersinthePacificOceanandtheAtlanticOceanare thesourcesoftheArcticOceanwater.TheAtlantic waterenterstheArcticOceanviatheFramStraitand theBarentsSea.Foritsdenserfeatureduetohigh salinity,mostofitsinkstothenorthofSvaldbardand circulatesinallthedeepbasinsintheArcticOcean, formingthedeepandbottomwatersoftheArcticO- cean(Aagaardetal.,1985;Rudelsetal.,1999).The BeringStraitistheonlychannelforthePacificwater toflowintotheArcticOce… 相似文献
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以1997年8月中旬和2011年10月中旬对三门湾附近海域开展的海域水质现状调查为依据,分析了近15 a间该海域水体环境氮、磷营养盐的分布现状及变化特征。结果表明:近15 a来,三门湾海域的无机氮和活性磷酸盐含量均成倍增长,水体营养程度由轻度富营养化逐步上升为重度富营养化;从营养结构来看,活性磷酸盐仍为限制性富营养化因子;大量的海水养殖是导致该海域营养盐大幅提高的直接原因。因此,为控制三门湾的富营养化现象进一步加剧,建议适度控制海水养殖规模,调整海水养殖结构,加强对三门湾沿岸排污控制,以获得养殖经济效益和生态环境效益的协调、可持续发展。 相似文献
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Martha Gledhill Constant M. G. van den Berg Rob F. Nolting Klaas R. Timmermans 《Marine Chemistry》1998,59(3-4)
Variations in the speciation of iron in the northern North Sea were investigated in an area covering at least two different water masses and an algal bloom, using a combination of techniques. Catalytic cathodic stripping voltammetry was used to measure the concentrations of reactive iron (FeR) and total iron (FeT) in unfiltered samples, while dissolved iron (FeD) was measured by GFAAS after extraction of filtered sea water. FeR was defined by the amount of iron that complexed with 20 μM 1-nitroso-2-napthol (NN) at pH 6.9. FeT was determined after UV-digestion at pH 2.4. Concentrations of natural organic iron complexing ligands and values for conditional stability constants, were determined in unfiltered samples by titration. Mean concentrations of 1.3 nM for FeR, 10.0 nM for FeT and 1.7 nM for FeD were obtained for the area sampled. FeR concentrations increased towards the south of the area investigated, as a result of the increased influence of continental run off. FeR concentrations were found to be enhanced below the nutricline (below 40 m) as a result of the remineralisation of organic material. Enhanced levels of FeT were observed in some surface samples and in samples collected below 30 m at stations in the south of the area studied, thought to be a result of high concentrations of biogenic particulate material and the resuspended sediments respectively. FeD concentrations varied between values similar to those of FeT in samples from the north of the area to values similar to those of FeR in the south. The bloom was thought to have influenced the distribution of both FeR and FeT, but less evidence was observed for any influence on FeR and FeD. The concentration of organic complexing ligands, which could possibly include a contribution from adsorption sites on particulate material, increased slightly in the bloom area and in North Sea waters. Iron was found to be fully (99.9%) complexed by the organic complexing ligands at a pH of 6.9 and largely complexed (82–96%) at pH 8. The ligands were almost saturated with iron suggesting that the ligand concentration could limit the concentration of iron occurring as dissolved species. 相似文献