共查询到20条相似文献，搜索用时 187 毫秒
1.
一秋龄性成熟中华绒螫蟹的生物学──1.外部形态特征及性腺变化 总被引：4，自引：0，他引：4
极大螺旋藻藻体ＳＯＤ聚丙烯酰胺梯度凝胶电泳呈现４条同工酶带,Ｈ２Ｏ２明显抑制该酶活性,ＫＣＮ对酶活性无影响,确认为Ｆｅ－ＳＯＤ。经硫酸铵分部盐析,离子交换柱层析及凝胶过滤,纯化到电泳单斑点均一程度。纯化的Ｆｅ－ＳＯＤ分子量为３９．３ＫＤ,亚基分子量为２０ＫＤ,金属元素分析表明,每个亚基含０．５５个Ｆｅ原子。该酶在紫外区最大吸收峰值为２７５．８ｎｍ,该酶氨基酸组成与蓝,绿藻和高等植物的Ｆｅ－ＳＯＤ相 相似文献
2.
极大螺旋藻铁型超氧物歧化酶的纯化及性质 总被引：3，自引：0，他引：3
极大螺旋藻 Ｓｐｉｒｕｌｉｎａｍａｘｉｍａ藻体ＳＯＤ聚丙烯酰胺梯度凝胶电泳呈现４条同工 酶带, Ｈ_ ２Ｏ_２明显抑制该酶活性, ＫＣＮ对酶活性无影响,确认为 Ｆｅ－ＳＯＤ经硫酸铵分部盐析、离子交 换柱层析及凝胶过滤,纯化到电泳单斑点均－程度．纯化的Ｆｅ－ＳＯＤ分子量为３９．３ＫＤ,亚基分子 量为２０ＫＤ金属元素分析表明,每个亚基含０ ５５个Ｆｅ原子,该酶在紫外区最大吸收峰值为 ２７５．８nｍ、该酶氨基酸组成与蓝、绿藻和高等植物的Ｆｅ－ＳＯＤ相似,但它含有较高的丙氨酸,酸性氨 基酸和碱性氨基酸比值与低等植物及原核生物相近而明显高于高等植物． 相似文献
3.
4.
5.
目的探讨ＰＨ值对Ｆｅ－ＥＤＴＡ造影效果的影响。方法;配制ＰＨ梯度５０－８０的０．５和０．１ｍｍｏｌ／Ｌ的Ｆｅ－ＥＤＴＡ液,观察ＳＥ序列「ＴＲ（ｍｓ）／ＴＥ（ｍｓ）２００／１５,２５００／８０」,信号变化,结果：Ｆｅ－ＥＤＴＡ的ＭＲ信号随ＰＨ值提高而减弱。 相似文献
6.
云南抚仙湖流域废弃磷矿区水污染现状 总被引：11，自引：5，他引：6
为了探讨不同形态磷酸盐对铜绿微囊藻（Microcystis aeruginosa）和蛋白核小球藻（Chlorella pyrenoidosa）藻细胞生长的影响,采用3种不同形态的磷酸盐：磷酸氢二钾（K2HPO4）,焦磷酸钠（Na4P2O7）和一聚磷酸钠（Na5P3O10）作为BG-11培养基中的添加磷源．从两种藻的生长趋势可以看出,在K2HPO4培养基中小球藻在生长初期生长速度显著高于微囊藻,当小球藻的生长到达静止期时,微囊藻的生长速度便超过了小球藻且其藻密度也高于小球藻;而在焦磷酸钠和二三聚磷酸钠培养基中,小球藻的生长速度要显著高于微囊藻．同时微囊藻和小球藻在K2HPO4培养基中的生长速度则始终高于另两种磷酸盐培养基中的生长速度．藻细胞碱性磷酸酶活性变化曲线也显示,小球藻的磷利用能力要高于微囊藻．由此可见,小球藻对磷的吸收利用能力高于微囊藻,从而表明铜绿微囊藻成为水华优势种并不是取决于其对磷酸盐的吸收利用能力。 相似文献
7.
HEDC控制体系的参数优化设计 总被引：4，自引：0，他引：4
介绍了高效被动阻尼控制装置（ＨＥＤＣ）的工作原理,利用Ｈａｍｉｌｔｏｎ原理,建立了ＨＥＤＣ控制体系地运动方程。通过仿真计算,分析和研究了ＨＥＤＣ参数对控制效果的影响规律,得到了一些有意义的结论。参数优化结果表明,通过合理设计参数,ＨＥＤＣ可以充分发挥阻尼器的工作潜力,取得十分显著的控制效果。 相似文献
8.
在不同的光照强度下,测定了铜绿微囊藻、斜生栅藻在不同生长期的藻细胞密度、粒径、叶绿素a浓度、浮游植物吸收系数以及比吸收系数.单因素方差分析表明,在整个培养周期中,光照强度对铜绿微囊藻及斜生栅藻的藻细胞密度、叶绿素a浓度以及440、675 nm处吸收系数均有着显著的影响.两种藻在光照强度为50μmol/(m2.s)条件下,藻细胞密度、叶绿素a浓度及吸收系数值相对最大.相关性分析表明:藻类特征波段440、675 nm吸收系数与叶绿素a浓度、藻细胞密度在不同光照条件下都存在着显著的正相关性,其中叶绿素a浓度与藻类吸收系数存在着幂函数的关系,而线性关系能更好的说明藻细胞密度与吸收系数之间的关系.在不同光照强度及培养时期,藻类比吸收系数在一定的范围内波动,随光强增加比吸收系数呈上升趋势.铜绿微囊藻440、675 nm处比吸收系数与叶绿素a浓度呈显著的负相关关系,而斜生栅藻比吸收系数与叶绿素a浓度之间无显著相关,体现了不同藻类由于色素组成及比例差异其色素包裹效应也各不相同.对不同光照强度下的铜绿微囊藻及斜生栅藻进行400～700 nm波段积分,得到了两者在5、50及100μmol/(m2.s)不同种光强下的平均比吸收系数分别为0.0144、0.0134、0.0160,0.0086、0.0088、0.0105 m2/(mg Chl.a),铜绿微囊藻比吸收系数明显大于斜生栅藻. 相似文献
9.
藻类对重金属的耐性与解毒机理 总被引：23，自引：1，他引：22
重金属是一类具有潜在危害的重要污染物,越来越多的重金属被排入水体,对水生生态环境构成严重威胁.藻类在长期响应重金属胁迫过程中,建立起一系列的适应机制.藻类通过控制重金属的吸收、富集、转运与解毒,使不同细胞组分中的重金属维持在正常浓度范围内.这些保护机制主要包括藻细胞的某些胞外组分与重金属结合,从而减少重金属进入胞内;在重金属诱导下藻细胞可合成金属结合蛋白或多肽;重金属诱导藻细胞合成一些代谢物使其免受伤害或修复由重金属胁迫造成的损伤;藻细胞通过液泡区室化作用使重金属远离代谢;藻细胞对重金属具有排斥与排出作用. 相似文献
10.
ORACLE数据库系统在中国数字化地震台网的应用 总被引：1，自引：1，他引：0
中国数字化地震台网是全球数字化地震台网的一部分。设在国家地震局地球物理研究所ＣＤＳＮ的数据管理中心及其所属的北京、海拉尔、西安等１１个野外台站的地震信息管理系统的均采用ＯＲＡＣＬＥ数据。本文介绍了ＯＲＡＣＬＥ数据库在ＣＤＳＮ应用的情况。 相似文献
11.
Comparison of Extraction Procedures for Assessing Soil Metal Bioavailability of to Wheat Grains 总被引：1，自引：0，他引：1
Agricultural soils have been analyzed to elucidate whether the trace metal distribution changes in relation to agricultural activities and to predict environmental risk. In addition to the extractability of Cu, Mn, Ni, Pb, and Zn in soils was compared by single extraction (hydrochloric acid (HCl), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), calcium chloride (CaCl2), water (H2O)), and sequential extraction procedures. The modified Community Bureau of Reference (BCR) sequential extraction procedure (three‐step) used to extraction of metals in soil samples. The extraction capacity of the analyzed metals was found by using single extraction procedures in the order: HCl > EDTA > DTPA > CaCl2 > H2O. A single correlation analysis was used to investigate the relationship between extractable metal concentrations in soil solutions and metal accumulation in wheat grains. Simple correlation analyses indicated that the extractable Pb and Ni of soils by HCl, EDTA, and DTPA single extraction procedures were significantly correlated with the metal contents of wheat grains. For CaCl2, H2O, and BCR extraction procedures there was a relatively poor correlation between the extractable Cu, Mn, Ni, Pb, and Zn of soils and metal contents of wheat grains. 相似文献
12.
Concentrations of 13 trace elements (V, Mn, Cr, Co, Cu, Zn, Se, Mo, Ag, Cd, Hg, Tl and Pb) were determined in muscle of bony fishes collected from coastal areas of the Caspian Sea (Kazakhstan, Azerbaijan, Turkmenistan and Iran). In all the fishes, Zn concentration was highest, followed by Cu, Se, Mn and Co, while levels of toxic elements (Ag, Cd, Cd, Tl and Pb) were relatively low. Concentrations of several elements were significantly varied between the species in each sampling area. For most of the trace elements examined, the concentrations decreased significantly with body weight of fishes. In contrast, a positive correlation with body weight was found for Co, Se and Pb concentrations in one fish species, and Hg in 2 fish species. Geographical difference in the concentrations of trace elements was examined using the Caspian roach collected from five stations of Iranian coastal waters. The concentrations of Co, Mo, Ag, Cd and Tl were higher in fishes from western stations than those from eastern stations, whereas the opposite trend was observed for Hg, indicating that local sources of trace metal pollution may be present in the Iranian coastal areas of the Caspian Sea. Levels of trace elements in Caspian fishes were relatively low in comparison to those of other regions, but Zn and Hg levels in some specimens exceeded the guideline values for food. 相似文献
13.
Overlying bottom water samples were collected in the Vistula River plume, southern Baltic Sea, (Poland) and analysed for dissolved and labile particulate (1 M HCl extractable) Cu, Pb, Zn, Mn, Fe and Ni, hydrological parameters being measured simultaneously. Particulate organic matter (POM), chlorophyll a and dissolved oxygen are key factors governing the chemical behaviour of the measured metal fractions. For the dissolved Cu, Pb, Zn, Fe and Ni two maxima, in the shallow and in the deeper part of the river plume, were found. In the shallow zone desorption from seaward fluxing metal-rich riverine particles account for markedly increased metal concentrations, as confirmed also by high particulate metal contents. For Pb, atmospheric inputs were also considered to have contributed to the elevated concentrations of dissolved Pb adjacent to the river mouth. In the deep zone desorption from detrital and/or resuspended particles by aerobic decomposition of organic material may be the main mechanism responsible for enrichment of particle-reactive metals (Cu, Pb, Zn) in the overyling bottom waters. The increased concentrations of dissolved Fe may have been due to reductive dissolution of Fe oxyhydroxides within the deep sediments by which dissolved Ni was released to the water. The distribution of Mn was related to dissolved oxygen concentrations, indicating that Mn is released to the water column under oxygen reduced conditions. However, Mn transfer to the dissolved phase from anoxic sediments in deeper part of the Vistula plume was hardly evidenced suggesting that benthic flux of Mn occurs under more severe reductive regime than is consistent with mobilization of Fe. Behaviour of Mn in a shallower part has been presumably affected by release from porewaters and by oxidization into less soluble species resulting in seasonal removal of this metal (e.g. in April) from the dissolved phase. The particulate fractions represented from about 6% (Ni) and 33% (Mn, Zn, Cu) to 80% (Fe) and 89% (Pb) of the total (labile particulate plus dissolved) concentrations. The affinity of the metals for particulate matter decreased in the following order: Pb > Fe > Zn > or = > Cu > Mn > Ni. Significant relationships between particulate Pb-Zn-Cu reflected the affinity of these metals for organic matter, and the significant relationship between Ni-Fe reflected the adsorption of Ni onto Fe-Mn oxyhydroxides. A comparison of metal concentrations with data from other similar areas revealed that the river plume is somewhat contaminated with Cu, Pb and Zn which is in agreement with previous findings on anthropogenic origin of these metals in the Polish zone of southern Baltic Sea. 相似文献
14.
Evaluation of metal contamination in coastal sediments of the Bay of Bengal, India: geochemical and statistical approaches 总被引：11，自引：0，他引：11
Surface sediment samples collected from the inner shelf region of the Bay of Bengal, were analysed for the major elements and total and acetic acid available trace elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Si, Zn) to evaluate geochemical processes influencing their distribution. Major elemental analysis showed that the sediments had high concentrations of Si and relatively low concentrations of Al and Fe. Both major elemental and trace metal concentrations indicated that the sediments represent weathered products of granite and charnockite. Normalization of metals to Al indicated relatively high enrichment factors for Pb, Cd, Zn and Cr. The higher proportions of nondetrital Pb (66%), Cd (41%) and Co (28%) reveal metal contamination due to anthropogenic inputs. Factor analysis (FA) identified six possible types of sedimentological and geochemical associations. The dominant factor accounting for 26.9% of the total variance identifies an anthropogenic input and accumulation of nondetrital Cd, Co, Cr, Ni and Pb. Association of these metals with CaCO3 reveals that shell fragments in the surface sediments are likely act as a carrier phase for nondetrital metals. The results are discussed in the context of the sources and pathways of elements in the Bay of Bengal. 相似文献
15.
The degree of trace metal pyritization in subtidal sediments of a mariculture area: application to the assessment of toxic risk 总被引：1，自引：0，他引：1
Four 2–3 m sediment cores were taken at the sites on the periphery of mussel raft concentrations in the subtidal zone of the inner Ría de Vigo (Galicia, NW Spain) with a view to evaluate the potential risk to mariculture from sediment-borne trace elements (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn). The distribution of each of these elements in reactive, organic, pyrite and silicate-bound fractions was determined at 64 samples, and these data were used to calculate the degree of trace metal pyritization (DTMP) of each metal/metalloid. In the top 10–20 cm, relatively oxic conditions led to As, Cd, Cu, Pb and Zn having large reactive fractions due to their association with Fe and Mn oxyhydroxides. At lower levels, anoxic conditions favoured by intense diagenesis led to the precipitation of trace metals and metalloids as sulphides, with or without association with pyrite. Particularly large pyrite fractions in the 20–100 cm layer are attributed to the organic matter of this layer being more marine in origin than that of deeper sediments. DTMP was greatest for Cu and As, and least for Pb, Zn and Cr. The risk of trace element toxicity in the event of disturbances instituting oxic conditions in these sediments is discussed. 相似文献
16.
The two marine algae, Chaetomorpha brychagona and Enteromorpha crinita are found abundantly on the iron ore tailings of Tolo Harbour, Hong Kong, with a rather high level of various metals. Tissue analysis of the algae revealed that the contents of heavy metals (Fe, Mn, Pb and Zn) were higher than in the population collected from the two uncontaminated sites far away from the tailings. It was suggested that the algae were able to adapt to such a harsh environment with a comparatively high level of trace elements and the lack of basic nutrients. However, further studies are needed before any conclusion can be drawn. The delicate situation of the land-locked sea, Tolo Harbour, where the tailings and future heavy industrial site are situated, should not be overlooked. 相似文献
17.
Sediments along the Israeli coast were examined to determine the effects of large scale dumping of sewage on trace metal contents. The Tel Aviv-Yafo sewage pipeline outlet is the largest point source of sewage effluent along the coast.Significant quantities of trace metals—Ag, Co, Cr, Cu, Hg, Ni, Pb and Zn—were found in sediments extending to a distance as far as 400 m from the sewage pipeline outlet. Beyond this point, sufficient dilution occurs to limit contamination by sewage to relatively low levels at present. In the contaminated area, there are seasonable variations with maximum trace metal concentrations occurring in the summer. The upper layers of the cores contain a greater trace metal burden than do the lower. 相似文献
18.
An eco‐friendly and inexpensive technique for wastewater treatment originated from inductively coupled plasma‐optical emission spectrometry (ICP‐OES) is presented within this paper. The proposed process comprised of loading waste crab shells in packed column for adsorption of heavy metal ions, followed by desorption using 0.01 M HCl. An exhaustive physical and chemical characterization of ICP‐OES wastewater revealed the complex nature of effluent, including the presence of 15 different metals and metalloid under strong acidic condition (pH 1.3). Based on the preliminary batch experiments, it was identified that solution pH played a major role in metal sequestration by crab shell with pH 3.5 identified as optimum pH. Rapid metal biosorption kinetics along with complete desorption and subsequent reuse for three cycles was possible with crab shell‐based treatment process. Continuous flow‐through column experiments confirmed the high performance of crab shell towards multiple metal ions with the column able to operate for 22 h at a flow rate of 10 mL/min before outlet concentration of arsenic reached 0.25 times of its inlet concentration. Other metal ions such as Cu, Cd, Co, Cr, Pb, Ni, Zn, Mn, Al, and Fe were only in trace levels in the treated water until 22 h. The performance of the treatment process was compared with trade effluent discharge standards, and the process flow diagram along with cost analysis was suggested. 相似文献
19.
20.
巢湖蓝藻聚集对重金属迁移释放的影响 总被引：1，自引：0，他引：1
以巢湖蓝藻水华聚集地西半湖表层沉积物与蓝藻为对象,研究了表层沉积物重金属(Cd、Cr、Cu、Zn、Pb、Ni和Mn)总量的分布特征.同时,利用BCR连续提取法对沉积物中重金属Cd和Mn的形态进行分析,模拟探究蓝藻腐殖化过程中重金属含量的变化,探讨了蓝藻腐殖化对重金属吸附-释放的影响.结果表明,各采样点表层沉积物重金属含量均不同程度超出背景值,且距离南淝河越近越突出.潜在迁移指数表明整个西半湖沉积物中重金属Cd比Mn更易形成二次污染.相关性分析显示重金属Cd和Mn各形态含量和总量之间均表现出极显著正相关.巢湖西半湖属于典型的藻型湖,Cd和Mn的来源和分布均与蓝藻聚集密切相关,结合实验室模拟蓝藻腐殖化过程对重金属的吸附-释放规律,认为蓝藻腐殖化过程会对Cd和Mn的迁移释放产生影响. 相似文献