镉对中华绒螯蟹鳃组织及其亚显微结构的影响

于1986年10月—1987年5月以不同浓度的镉(6.25,12.5和25.0mg/L),对采自长江口的中华绒螯蟹进行了急性毒性试验,以光镜和电镜观察。结果表明,受镉作用后,整个鳃叶增厚,血腔增大;血细胞增多,上皮层破坏直至解体;鳃上皮细胞的亚显微结构因镉的作用顶膜微绒毛和底膜内折消失,线粒体膨胀直至解体。以统计分析检验了对照组和不同镉浓度组处理的蟹鳃之间的形态指标的差异,并分析了这些形态指标的变化同镉浓度的相关性。通过对鳃上皮细胞与鳃生理功能关系的分析,认为镉对鳃组织及细胞结构的损害影响了鳃组织的能量代谢、离子主动转运机制及渗透压调节能力。     

镉离子对鲫鱼肾细胞超微结构的影响

应用透射电镜的方法，研究了镉的三种浓度对鲫鱼肾细胞超微结构的影响。结果表明：镉离子染毒4天后，肾细胞超微结构即出现变化，且随着处理浓度的升高，变化渐趋明显，主要表现在细胞核和线粒体。细胞核核膜肿胀、弥散、最后解体。线粒体双层膜解体，形成空白区，嵴断裂、膨大和扭曲。此外，内质网膨胀、空泡化、扭曲打转，溶酶体数量和类型随镉处理浓度的升高而增多。     

亚心形扁藻超氧化物歧化酶活性对镉和铜的应答

以亚心形扁藻为实验材料,对不同浓度重金属镉(Cd2 )和铜(Cu2 )作用下亚心形扁藻的超氧化物歧化酶(SOD)活性的变化和膜脂过氧化作用进行了探讨,以期了解藻类抗重金属的机制。结果表明:随着Cd2 和Cu2 浓度的增加亚心形扁藻的SOD的活性逐渐升高,但高浓度Cd2 可导致SOD活性活性下降。膜脂过氧化实验结果显示,半抑制浓度的重金属处理72hr后,膜脂过氧化产物丙二醛(MDA)显著提高。用72h半抑制浓度的重金属处理亚心形扁藻随时间的变化关系表明,在最初的12hr内SOD活性被两种重金属离子诱导迅速升高,然后逐渐趋于平稳。总之,SOD活性的变化与重金属的种类、浓度和处理时间有关。     

地衣芽孢杆菌胞外产物消化活性的研究

将地衣芽孢杆菌Bacillus licheniformis的胞外产物置于不同的pH、温度和金属离子条件下,分别测定其蛋白酶、淀粉酶、脂肪酶活性的变化。结果表明,当pH为7.5—8.5时胞外产物表现出较高的蛋白酶和淀粉酶活性,胞外产物消化脂肪的最适pH为9.0—10.0。胞外产物水解淀粉、脂肪和蛋白质最适温度分别为60—80、40—60和50—70℃,60℃时蛋白酶活力最大。试验测定了8种金属离子对胞外产物活性的影响,发现Mg2+、Zn2+Cu2+可抑制其水解蛋白质,而Ca2+、Fe3+、Mn2+和Ba2+却无此影响;在胞外产物消化脂肪底物时Co2+、Fe3+、Mn2+和Ba2+均能抑制其活力,而Mg2+、Zn2+能使其消化活力升高,与前者相比,金属离子对淀粉水解的影响相对较小,仅Cu2+有一定的抑制作用,其它离子对其均无明显的影响。还研究了不同胞外产物浓度与生物学活性的相关性,发现当反应体系中胞外产物浓度升高时水解蛋白质的活力会相应降低,但对脂肪的消化活力则与胞外产物的浓度呈正相关。反应体系中胞外产物的浓度在0—132.4μg.ml-1时其水解淀粉的活力随浓度的升高而升高,浓度为191.0μg.ml-1时活力最大,浓度大于191.0μg.ml-1时活力不再变化,稳定在一个较高的水平。     

Cd~(2+)、Pb~(2+)、Hg~(2+)对泥蚶鳃及消化腺显微结构和超微结构的影响

研究了9μg/L暴毒浓度的镉(Cd2+)、铅(Pb2+)和1.08μg/L暴毒浓度的汞(Hg2+)对泥蚶鳃和消化腺组织显微结构和超微结构的影响。实验处理时间为28d。3种重金属胁迫下鳃组织显微结构观察显示鳃丝排列混乱,血细胞堆积现象严重;超微结构观察发现,Cd2+和Hg2+胁迫下鳃细胞发生细胞核皱缩,有大量的线粒体和溶酶体。Pb2+攻毒组的鳃细胞中聚集大量的嗜锇性物质。3种重金属胁迫下消化腺组织显微结构显示消化腺细胞破碎,完整度变差;从超微结构来看,在Cd2+和Pb2+的胁迫下,消化腺细胞中出现嗜锇性物质;另外在Pb2+胁迫下,消化腺细胞中有溶酶体;然而在Hg2+胁迫下,泥蚶消化腺细胞受到的影响不明显。本研究推测在重金属胁迫下,泥蚶可能会通过溶酶体和重金属形成不溶性颗粒,从而将重金属隔离进行解毒作用;大量产生的线粒体可能对重金属引起的氧化胁迫进行呼吸补偿反应。     

镉胁迫对凡纳滨对虾血清中一氧化氮合成酶和超氧化物歧化酶活性的影响

研究了不同浓度Cd2 (0.05、0.5和5mg·L-1)对凡纳滨对虾Litopeneaus vannamei血清中的总一氧化氮合成酶(NOS)、诱导型一氧化氮合成酶(iNOS)和超氧化物歧化酶(SOD)活性的影响.结果表明,镉胁迫促使总NOS活力升高依剂量而异,中(0.5mg·L-1)、低(0. 05mg·L-1)剂量组凡纳滨对虾血清中总NOS活力在24-48h显著高于对照组,而高剂量组(5mg·L-1)在12-48h血清中总NOS活力与对照组相比无显著差别; iNOS活力变化趋势与总NOS活力相似,但中、低剂量组之间iNOS活性无显著差异.镉胁迫促使凡纳滨对虾血清中SOD活力短暂升高,但高剂量在24-48h对SOD活力呈明显的抑制效应.     

Cd2+与Zn2+的联合效应对马氏珠母贝(Pinctada martensii)受精率的影响

采用中心组合设计和响应曲面法在实验室条件下研究了Cd2+与Zn2+对马氏珠母贝受精率的影响。Cd2+、Zn2+的浓度范围分别为0.030—20mg/L、0.100—20mg/L。结果表明:Cd2+与Zn2+两因子对马氏珠母贝受精率的一次效应极显著(P<0.01);Cd2+与Zn2+两因子一次互作效应极显著(P<0.01)。经响应曲面法分析,随着Cd2+与Zn2+浓度的增加受精率呈下降趋势,当Zn2+浓度在最低浓度(0.100mg/L)时,受精率随着Cd2+浓度的上升而下降;当Cd2+浓度在最低浓度(0.030mg/L)时,受精率随Zn2+浓度的上升而先下降后升高。本实验建立了马氏珠母贝受精率与Cd2+、Zn2+间关系的模型方程(R2=0.996,Adj.R2=0.987,Pred.R2=0.887,P<0.01)并可用于预测Cd2+、Zn2+对马氏珠母贝受精率的影响。     

重金属胁迫对两种海洋饵料微藻的急性毒性效应研究

在模拟生态环境条件下研究了铜(Cu2+)、镉(Cd2+)和锌(Zn2+)3种重金属离子对2种海洋饵料微藻(青岛大扁藻(Platymonas helgolandica)和等鞭金藻8701(Isochrysis galbana 8701))的急性毒性效应,分析其对种群增长的影响,并利用透射电镜对微藻亚显微结构的变化进行分析。在实验浓度范围内,2种微藻的种群增长对3种重金属离子的急性胁迫表现出类似的变化趋势,随着胁迫浓度的增加,微藻的相对增长率均呈现出不断下降的趋势;通过比较2种微藻的48hEC50和96h-EC50发现:3种重金属离子的毒性程度为Cu2+Cd2+Zn2+,等鞭金藻8701对重金属胁迫的敏感性高于青岛大扁藻。2种微藻的亚显微结构观察显示,二者的膜结构及细胞核对Cu2+胁迫并不太敏感;与对照组相比等鞭金藻8701的色素体及贮能物质受影响较严重,而青岛大扁藻的叶绿体及淀粉粒受影响较大。     

防污剂Irgarol 1051对三角褐指藻生长及生理特性的影响

为研究防污剂Irgarol 1051对微藻生长及生理生化特性的影响,以三角褐指藻(Phaeodactylum tricornutum)为材料,分析了Irgarol 1051对P.tricornutum生长、叶绿素a含量、可溶性蛋白质含量、超氧化物歧化酶(Superoxide dismutase,SOD)活力及丙二醛(Malondialdehyde,MDA)含量等的影响。结果表明:Irgarol 1051可抑制P.tricornutum的生长,并诱导其产生耐受性;P.tricornutum中叶绿素a、可溶性蛋白质含量及SOD酶活力等均随Irgarol 1051质量浓度的增加而升高,以维持其生长和生理状态;随着Irgarol 1051质量浓度的升高,藻细胞中MDA含量显著增加,表明细胞中活性氧自由基(Reactive oxygen species,ROS)过量积累,这将破坏藻细胞的膜结构与功能。研究结果将为探讨Irgarol1051对微藻的效应机制及其环境风险评价提供数据资料和科学依据。     

突降盐度胁迫对大黄鱼(Pseudosciaena crocea)血清生理生化及鳃丝Na+/K+-ATP 酶活性的影响

采用海水盐度由25突降至21、17和13胁迫大黄鱼(Pseudosciaena crocea)的方法,研究了48h内血清生理生化和鳃丝Na+/K+-ATP酶活性的变化。结果表明,实验过程中三个盐度突降组的血清Na+、Ca2+离子浓度均未发生显著变化(P>0.05),血清K+浓度均显著升高(P<0.05),且升高幅度与盐度突降幅度呈正相关,最大值达14.03mmol/L(盐度13组,48h);血清Cl浓度在盐度21组未发生显著变化(P>0.05),17和13组则在48h时显著降低(P<0.05);三个盐度突降组的血清酶ALT、AST、LDH、CK-MB活性均显著高于对照组(P<0.05),随胁迫时间的延长呈先升后降的趋势,且变化幅度均与盐度突降幅度呈正相关;三个盐度突降组的鳃丝Na+/K+-ATP酶活力均呈先升后降的变化趋势,除盐度21组在12h时高于对照组外,活力均显著低于对照组(P<0.05),且降低幅度与盐度突降幅度呈正相关;到实验15天时,死亡率随盐度突降幅度增大而升高。     

泥螺肝胰腺细胞的超微结构和功能

利用透射电镜技术研究了泥螺(Bullactaexarata)肝胰腺细胞的超微结构。结果表明,泥螺的肝胰腺主要由4类细胞构成:泡状细胞(B细胞)、吸收细胞(R细胞)、纤维细胞(F细胞)和胚细胞(E细胞)。B细胞大,长柱状,胞质中有许多消化泡;R细胞的脂滴数量多,体积大,具少量的线粒体;F细胞含有极丰富的粗面内质网、线粒体等结构,但脂滴的数量远远少于R细胞。E细胞为多边形,核大而圆,粗面内质网少,线粒体小而狭长。根据这4种细胞的超微结构特点,指出了泥螺肝胰腺的功能,并探讨了肝胰腺细胞的分化序列。     

中国对虾组织细胞中的过氧化物酶体

运用电镜细胞化学技术，研究中国对虾(Penaeus chinensis)组织细胞中的过氧化物酶体，透射电镜下观察中国对虾的淋巴器、肝胰腺、触角腺和中肠4种组织。观察显示：过氧化物酶体主要存在于肝胰腺细胞和触角腺的迷路上皮细胞中。在肝胰腺的R-细胞中过氧化物酶体的形成与粗面内质网、脂滴和胞质溶胶有密切关系。肝胰腺中的R-细胞和触角腺的迷路上皮细胞富含过氧化物酶体，提示这两个组织在对虾降解外来有毒物质的过程中发挥着重要的作用。     

镉胁迫对大弹涂鱼(Boleophthalmus pectinirostris)血清转铁蛋白和血红细胞的影响

提要采用人工染毒的方法,进行了镉污染暴露对大弹涂鱼血清转铁蛋白(STF)铁结合能力和血红细胞影响的研究。结果表明,自染毒第7天开始,血清铁浓度,血清铁饱和度稳定上升并与对照组比较有统计学上的极其显著性差异,且对镉敏感。而转铁蛋白的总铁结合力和不饱和铁结合力则无稳定的趋势。血红蛋白的A值与血细胞浓度均呈稳定下降趋势,并于染毒11天后开始出现显著性降低。揭示镉胁迫引起的大弹涂鱼机体损伤与它对动物机体的铁代谢影响紧密相关。大弹涂鱼血清的铁饱和度、血清铁浓度、血红细胞的吸光度和浓度可以作为长期海洋污染暴露的生物标记,其中血清的铁饱和度可靠度最高,而血红细胞的吸光度和浓度的测定最为简便。推测,其他鱼类在镉胁迫下也应当有相似的血液生理变化,在明确健康对照的相关指标变化范围后,可以便利地监控环境中的重金属污染。     

镉胁迫条件下大弹涂鱼(Boleophthalmus pectinirostris)外周血微核标记及肝脏过氧化物酶标记的变化

采用静态毒性实验方法,研究重金属镉胁迫条件下大弹涂鱼外周血微核率和肝脏过氧化物酶活性的变化。结果表明,在0.05mg/L Cd2 浓度组,10d时检测到微核率极显著升高;0.5mg/L和5mg/L组5d时就可检测到微核率极显著升高,到10d时微核率达到最高值;10d时转入清洁海水后,3个组在15d再次出现一个微核率的最高值。大弹涂鱼肝脏过氧化物酶标记包括谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽转硫酶(GST)。3个组的GSH-Px酶活性和5mg/L浓度组GST酶活性在12h后显示出极显著变化,3个组GST酶活性在24h检测到极显著差异;在转入清洁海水5d时,3个组GSH-Px酶活性和对照组相比可检测到极显著差异,而3个组的GST酶活性均无显著差异。研究结果表明,大弹涂鱼外周血微核标记和肝脏过氧化物酶标记能够灵敏地指示水环境中的镉污染;大弹涂鱼外周血微核标记和肝脏内过氧化物酶标记具有一定的互补作用。     

海洋沉积物中酸溶硫化物对二价金属镉的地球化学特征及生物毒性的影响

通过海洋沉积物镉加标实验、沉积物间隙水分析和对加标沉积物毒性的10天底栖端足类生物检验，重点探讨在硫化物存在条件下，二介有毒金属镉在沉积物－间隙水系统中的地球化学分配和化学活性，及镉在沉积物中的化学活性与生物毒性间的关系。研究结果表明，镉加标沉积物的毒性与间隙水中镉浓度呈正相关，而与沉积物镉总量无关。在硫化物存在条件下，沉积物－间隙水系统中，二价镉在固、液两相同的分配主要受酸溶硫化物（AVS）影响。AVS归一化沉积物中二价镉含量可作为预测和评价二价有毒金属镉的化学分配行为和生物可获性或毒性的有效方法。酸解硫化物时同步提取的金融镉SEMCd^2 与AVS的摩尔浓度之比[SEMCd^2 ]/[AVS]可用作评价缺氧状况下镉沾污沉积物的环境质量和毒性的判据。     

THE EFFECT OF CADMIUM ON THE ACTIVITY OF ALKALINE PHOSPHATASE IN MUSSEL VIRIDIS

The paper preliminarily discusses the effects of cadmium pollution on the alkaline phosphatase of mussel, mytilue viridid. The results show the cadmium pollution has a inhibition on the alkaline phosphatase, and the degree of inhibition rises with the increases of concerntration if cadmium in seawater. When the concentration is within the range of 1-500 ppb, the percentage of inhibited emzyme has a linear relationship with the logarithm of cadmium concentration. The results also prove that the salinity may increase the effects of cadmium on emzyme. The inhibition which may be indirect or secondary effects is reversible.Mussels play a purification role in the waste water containing cadmium, the purification rate of which may as high as 125 mg Cd2 gram (mussel)/day. This is a prospective method in purification and removing of cadmium.The study of effects of cadmium pollution on the alkaline phosphatase of mussel shows that in the study of effects of pollutants on aquatic organisms, biochemical index may     

Trace metal uptake by the Chinese mitten crab Eriocheir sinensis: the role of osmoregulation

Changes in salinity affect the bioavailability and consequent uptake of trace metals by euryhaline invertebrates. In many cases, salinity-related effects on metal uptake can be explained by changes in chemical speciation but salinity may also influence uptake indirectly through its action on osmoregulatory mechanisms. Specifically, it can be hypothesised that trace metal uptake may be reduced at salinities approaching the isosmotic point of a species because, at this point, there is reduced activity of ionic exchange pumps. The present study tested this hypothesis using the Chinese mitten crab, Eriocheir sinensis, a hyper-hypoosmoregulator with an isosmotic point around 33 per thousand. Crabs were exposed to radio-labelled cadmium and zinc at 23, 33 and 43 per thousand for 4 days. To eradicate speciation effects, crabs were exposed to the same concentration of the radio-labelled free metal ion (estimated using MineQL computer software) at each salinity. Haemolymph samples were taken daily and radio-labelled metal concentrations were estimated from radioactivity counts and used to provide relative measures of metal uptake. Neither cadmium nor zinc uptake was lowest at the isosmotic point. The uptake of cadmium increased significantly with increase in salinity, while the uptake of zinc showed no significant change with increased salinity. Thus changes in trace metal uptake rates in E. sinensis do not appear to be controlled only by changes in free metal ion concentrations. The different effects of salinity change on the uptake of cadmium and zinc (in the absence of free metal ion change) also indicate that physiological responses to osmotic change alone do not control metal uptake rates for this species.     

In vitro and in vivo inhibition of acetylcholinesterase and carboxylesterase by metals in zebrafish (Danio rerio)

Metals are natural components in ecosystems; however, if these elements are in excess, they can have adverse effects on living organisms. This study analyzes the interference of copper, lead, iron and cadmium in acetylcholinesterase (AChE) and carboxylesterase (CbE) activities in zebrafish. AChE was significantly inhibited in vitro by copper, iron, lead and cadmium at higher concentrations (10 and 20 mmol/L), whereas CbE was inhibited only at a concentration of 20 mmol/L. In vivo, only lead and cadmium were able to cause AChE inhibition at higher concentrations, while iron didn't cause any changes, and copper promoted an increase in AChE activity at a concentration of 0.06 mg/L. CbE activity did not change at any of the times (two and seven days) and concentrations tested, except in the case of copper exposure, which resulted in a decrease in CbE activity. Indeed, iodoacetamide treatment didn't changed AChE neither CbE activities, results which indicate that the metal inhibiting effect is probably not due to its biding to thiol groups close the active site of the enzyme. This outcome reveals that metals are important esterase inhibitors in zebrafish, and should be considered in environmental monitoring studies that use esterase inhibition as exposure biomarkers of organophosphate and carbamate pesticides.     

Liver cadmium uptake,catalase inhibition and cadmium thionein production in the killifish (Fundulus Heteroclitus) induced by experimental cadmium exposure

Liver catalase activity was used as an index of cadmium poisoning in the killifish, Fundulus heteroclitus, and was found to be inhibited following both in vivo and in vitro exposure to dissolved cadmium at a concentration greater than 1 mg/litre. Pre-exposure at 1 mg Cd/litre prevented catalase inhibition at higher subsequent doses of cadmium. Comparison of the effects of in vivo and in vitro exposure showed in vivo exposure to cadmium to result in greater catalase inhibition.Cadmium and copper binding was determined by gel chromatography and found to occur at three distinct liver cytosol fraction peaks. Both metals showed enhanced cytosol concentrations with cadmium exposure and relative changes in peak levels as related to cadmium exposure regimes. Cadmium thionein (molecular weight of 7–10,000) was found in the killifish liver and was correlated with adaptive responses in liver catalase activity. High molecular weight cadmium binding was found to be a better index of cadmium toxicity to liver catalase than total liver cadmium concentration.