海黍子和脆江蓠对重金属锌、镉富集的比较研究

采用室内培养实验方法,研究了褐藻海黍子(Sargassum muticum)和红藻脆江蓠(Gracilaria chouae)在不同质量浓度的锌和镉溶液里15 d,藻体的生长和体内金属离子含量的变化。结果表明:两种藻的生长速率与暴露溶液金属质量浓度呈负相关,藻体内积累金属离子的量和溶液的金属质量浓度呈正相关,藻体内金属离子的含量均在培养3 d后显著增加,且随着培养时间的延长而持续增加。海黍子和脆江蓠对重金属Zn~(2+)的富集能力明显高于对Cd~(2+)的富集能力,在相同条件下,海黍子对重金属Zn~(2+),Cd~(2+)的积累量明显高于脆江蓠。以上研究结果对利用藻类修复重金属污染的海洋水体能起到一定的指导和参考作用。     

金属离子对中肋骨条藻的胁迫效应及叶绿素a 合成的影响

研究中肋骨条藻(Skeletonema costatum)生长对不同质量浓度的5种金属离子胁迫的响应,探讨5种金属离子对中肋骨条藻叶绿素a合成的影响.结果显示:生长方面,中肋骨条藻对Cd2+和Ba2+的响应较明显,培养至第10天,Cd2+质量浓度为1、10 mg/L组生长量仅有对照组的59％及43.6％; Ba2+质量浓度为2 mg/L组到第10天是对照组的69.4％,而0.5 mg/L组超过对照组38.9％;中肋骨条藻对其他金属离子的胁迫响应不明显;叶绿素合成方面,Cd2+质量浓度为1 mg/L时,叶绿素a合成量达最高,高于对照组157％;而Ba2+质量浓度为0.5、1 mg/L时,超出对照组的116％和483％;其他金属离子对中肋骨条藻叶绿素a合成均起抑制作用,各个质量浓度组均低于对照组,其中pb2+质量浓度为0.3 mg/L、Mn2+质量浓度为1 mg/L及Li+质量浓度为0.1 mg/L时,叶绿素a含量达最低值,仅为对照组的34.1％、37.5％和17.6％;结论是质量浓度为0.5 mg/L的Ba2+可促进中肋骨条藻的生长及叶绿素的合成,对其产业化规模培养具有重要意义.     

鼠尾藻(Sargassum thunbergii)对邻苯二甲酸二甲酯(DMP)胁迫的响应

邻苯二甲酸二甲酯(dimethyl phthalate,DMP)是近海环境有机污染物之一,不仅对海洋生物造成毒害,且能在生物体内富集和放大,对海洋生态系统形成严重威胁。本文以鼠尾藻(Sargassum thunbergii)为研究对象,通过测定比生长速率、叶绿素a含量、光合和呼吸速率、光合基因rbcL转录水平上的相对表达量等指标,研究了鼠尾藻对不同浓度DMP的响应。结果表明,低浓度的DMP(0.lmg/L)短时间内(≤15d)能促进鼠尾藻的生长和叶绿素a的合成,并使藻体的光合作用增强,诱导光合基因rbcL的表达,而在高浓度DMP(≥0.3mg/L)的作用下,鼠尾藻的生长速率、光合和呼吸速率、rbcL基因的表达量均随着暴露时间的延长呈明显下降趋势,且DMP浓度越高,降幅越大。以上研究结果对了解DMP对鼠尾藻胁迫的影响机制奠定了基础,为保护海洋经济藻类的养殖环境提供了理论依据。     

潮间带大型海藻孔石莼和鼠尾藻对铜胁迫的生理响应

以潮间带大型海藻孔石莼(Ulvapertusa)及鼠尾藻(Sargassumthunbergii)为试材,研究了不同Cu~(2+)浓度(0, 0.5, 1.0, 1.5, 2.0 mg/L)胁迫下海藻中叶绿素含量、光合特性和ATP酶活性的响应变化。结果表明,随Cu~(2+)浓度增加,孔石莼及鼠尾藻的光合色素含量、叶绿素荧光参数包括光能利用效率(alpha)、最大相对电子传递速率(rETRm)、半饱和光强(IK)及PSⅡ最大光能转化效率(F_v/F_m)随胁迫浓度升高均呈下降趋势,其中孔石莼F_v/F_m下降幅度更大;2种海藻中Na~+K~+-ATP及Ca~(2+)Mg~(2+)-ATP酶活性总体上随Cu~(2+)浓度的升高亦呈降低趋势,且孔石莼降低幅度尤为显著。这些结果表明,随胁迫程度加剧,孔石莼及鼠尾藻光合作用受抑,代谢酶活性降低,藻体遭受不可逆的严重损伤,处理体现出较明显的剂量效应;二者相比,鼠尾藻相比孔石莼对铜胁迫具更强的耐受性;叶绿素荧光参数F_v/F_m测定结果极其稳定且与胁迫程度相关极显著,可作为海藻生长及生理代谢对重金属耐受性的有效评价指标。     

栉孔扇贝对镉的富集及释放规律的研究

通过暴露染毒方法研究了栉孔扇贝对镉离子(Cd2+)的35d富集与30d释放规律。结果表明:栉孔扇贝对镉有很强的富集性,体内的镉含量与暴露溶液里的Cd2+浓度呈正相关;栉孔扇贝对镉的释放速率随着暴露水体中镉浓度的增加而减慢。应用双箱动力学模型,通过非线性拟合得到了栉孔扇贝对Cd2+的吸收速率常数k1随着外部水体中镉浓度的增大而减小,生物富集系数BCF则随着外部水体中镉浓度的增大而减少。当镉浓度为0.05mg/L时BCF仅为3 730,而当镉浓度为0.000 5mg/L时BCF达到1.79×1011。平衡状态下栉孔扇贝体内镉含量(CAmax)随着水体中镉浓度增加急剧下降,与水体中镉浓度呈负相关;排出速率常数k2、生物学半衰期B1/2与低浓度镉无明显相关性,随着镉浓度的增大k2显著降低而B1/2显著增大。验证了双箱动力学模型适用于栉孔扇贝对Cd2+的生物富集与释放规律研究。     

重金属胁迫对杜氏盐藻生长及叶绿素荧光特性的影响

研究了杜氏盐藻Dunaliella salina在不同浓度的Cu2+、Zn2+、Cd2+等重金属离子胁迫一段时间(24、48、72和96 h)后,叶绿素荧光特性的变化情况。测定的主要参数有:PSII的最大光能转化效率(Fv/Fm)、PSII的潜在活性(Fv/Fo)、PSII的实际光能转化效率(Yield)、相对光合电子传递效率(rETR)、光化学淬灭(qP)和非光化学淬灭(NPQ)。研究结果表明,当Cu2+浓度范围在600~800μmol/L时,杜氏盐藻的Fv/Fm、Fv/Fo、Yield、rETR和qP均明显降低,NPQ变化不规律,随着胁迫时间的延长,除qP在96 h时有所上升外,各荧光参数均逐渐降低;Zn2+胁迫下Fv/Fm、Fv/Fo、Yield和rETR随着浓度的增加而降低,NPQ先下降后上升,qP仅在Zn2+浓度范围(800~3200μmol/L)下明显下降,随着胁迫时间的延长,各荧光参数均逐渐降低;Cd2+胁迫下各荧光参数均明显下降,随着胁迫时间的延长,Fv/Fm、Fv/Fo和NPQ先下降后上升,在48 h时达到最低值,Yield、rETR和qP均逐渐降低。在3种重金属离子胁迫下,细胞密度和叶绿素相对含量也显著降低。根据3种重金属离子的半抑制浓度(EC50),其毒性大小顺序为Cu2+Cd2+Zn2+。     

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。     

Zn2+和Cd2+单独及联合作用对青蛤肝胰腺消化酶活性的影响

以酶学分析的方法研究了Zn2+、Cd2+单独及联合作用(Zn2++ Cd2+)对青蛤肝胰腺蛋白酶、淀粉酶和纤维素酶活性的影响,实验浓度分别设置为0、10、20、40、80 mg/dm3,染毒时间为4d.实验结果表明,3种消化酶活性大小为淀粉酶＞蛋白酶＞纤维素酶.不同浓度的Zn2+对淀粉酶表现为显著的抑制作用;除40 mg/dm3浓度组的Zn2+对蛋白酶有激活作用外,其余浓度组的Zn2+对蛋白酶均有抑制作用;除10 mg/dm3浓度组Zn2+对纤维素酶有抑制作用外,其余浓度组的Zn2+对纤维素酶均有激活作用.不同浓度的Cd2+对淀粉酶、蛋白酶和纤维素酶均有不同程度的抑制作用,且表现出不同的抑制趋势;不同浓度的Zn2++Cd2+对淀粉酶和蛋白酶均表现为显著的抑制作用,且随着实验设置浓度的升高抑制作用加强,而20 mg/dm3和40 mg/dm3浓度组对纤维素酶表现出激活作用,其他两个浓度(10、80 mg/dm3)则表现为抑制作用.青蛤肝胰腺消化酶活性可作为Zn2+和Cd2+污染监测的一种生物标记物.     

重金属Cu2+胁迫对红树植物秋茄幼苗生长及某些生理特性的影响

为揭示铜污染对红树植物的毒性效应和植物的抗性机制,作者研究了红树植物秋茄(Kandelia obovata)幼苗在不同质量浓度的Cu2+(0,0.5,5,50,100,200 mg/L)离子胁迫90 d后,幼苗生长、部分生理指标的变化以及Cu2+在幼苗体内的累积情况。测定的主要参数有:幼苗的主根长度、侧根数目、生物量、叶片的光合速率、色素含量、可溶性糖和蛋白含量及抗氧化酶系活性。研究结果表明:当Cu2+浓度范围在(0.5~200 mg/L)时,主根长度、侧根数目、生物量、叶片的光合速率、色素含量、可溶性糖和蛋白含量均呈降低趋势;根系POD活性持续升高,叶片和根系的SOD和CAT活性呈先升后降趋势;根系MDA含量在整个Cu2+胁迫浓度范围保持相对稳定,叶片MDA含量在高浓度Cu2+胁迫下增加;Cu2+主要累积在根部而向地上部分转运的较少。根据不同浓度的Cu2+离子对秋茄幼苗生长及生理特性影响,秋茄幼苗对Cu2+胁迫的耐受质量浓度范围为5~50 mg/L。     

Cd2+和Cu2+对泥蚶的急性毒性和联合毒性试验

为了解重金属Cd2+和Cu2+对泥蚶的毒害程度和泥蚶对重金属Cd2+和Cu2+的解毒能力,用毒理学实验方法研究了Cd2+和Cu2+对泥蚶(Tegillarca granosa)的急性毒性和联合毒性效应。结果表明:Cd2+、Cu2+对泥蚶的96 h半致死质量浓度分别为6.189、0.460 mg/L;安全质量浓度分别为0.062、0.005 mg/L;相对毒性Cu2+Cd2+。在1︰1毒性单位的联合作用下,Cd2+和Cu2+对泥蚶96 h的半致死质量浓度分别为1.984、0.147 mg/L;安全质量浓度分别为0.020、0.001 mg/L。2种重金属离子的联合毒性大于任一重金属离子的毒性,联合毒性表现为协同作用。     

鼠尾藻生长、藻体成分及其生境的初步研究

对威海小石岛附近海区鼠尾藻(Sargassum thunbergii)的生长、藻体成分和水体中氮、磷等营养元素的月份变动情况进行了初步研究.结果表明,研究海区水体中硝酸氮的含量具有明显的月份变化,5～10月含量较低,11～4月含量较高;相对于硝酸态氮,氨氮的含量较低,随月份变动也较小;总无机氮的含量变化与硝酸氮含量变化趋于一致;总无机磷含量随月份的变动也较大,在2～6月含量较低,11～1月含量较高.鼠尾藻生长有着明显的月份变化,4～5月生长最快,6～7月藻体达到最大长度;侧枝一般在4月开始出现,7月达到最长.对鼠尾藻体内的碳、氮、磷、碳水化合物以及色素进行测定的结果表明,鼠尾藻体内的碳含量变化较小,一般在25.6%～33.0%之间;氮的含量变化较大,12～5月含量较高,超过3%,7～11月含量较低,低于3%;磷的含量也具有很大的波动,在11～4月含量较高,5～10月含量较低.色素含量具有明显的月份变化,12～3月含量较高,7～10月含量较低.碳水化合物含量在4～7月时较高,最低出现在8～9月.     

不同配比饲料对刺参C、N、P营养盐收支的影响

本实验采用5种含有不同比例(即20∶80、40∶60、60∶40、80∶20和100∶0)的鼠尾藻和海泥的颗粒饲料喂养刺参(Apostichopus japonicus),并比较了不同饲料条件下刺参C、N、P营养盐的收支过程。结果表明:刺参C、N、P营养盐收支过程和饲料中鼠尾藻的含量显著相关(P<0.05)。刺参的摄食率和排粪率随着饲料中鼠尾藻含量的增加而显著降低(P<0.05);刺参的耗氧率、排氨率、排磷率,以及对C、N、P营养盐的摄入率、生长余力和吸收效率均随着饲料中鼠尾藻含量的增加而显著变大(P<0.05)。当饲料中鼠尾藻添加量大于60%时,刺参对营养元素的生长余力和吸收效率无显著变化(P>0.05),因此对于成参而言,饲料中鼠尾藻和海泥的比例为60∶40是较为理想的配制比例,既可以满足刺参生长代谢所需要的主要营养元素,又能够最大限度地减少刺参养殖活动营养盐的排放。     

The influence of cyclic exposure on the accumulation of heavy metals by Mytilus edulis planulatus (Lamarck)

Accumulation of cadmium, copper, lead and zinc in the tissues of Mytilus edulis planulatus was examined under cyclic conditions of exposure in order to establish whether the rate of accumulation of the metal is proportional to the time exposed to the elevated concentrations. When exposed to a single metal, the accumulation of lead and zinc was directly proportional to the exposure time, but that of copper was not. Under simultaneous exposure to all four metals both lead and cadmium were accumulated in direct proportion to the exposure time, while copper and zinc were not. Accumulation of the three metals cadmium, copper and zinc was influenced by the presence of other metals.     

鼠尾藻劈叉筏式养殖试验

2004~2005年,在山东省威海海区进行了鼠尾藻劈叉筏式养殖试验。2004年试验持续123d,试养鼠尾藻2×667m2,平均株长由5.5 cm生长至79.1 cm,鲜藻产量2.52 kg/m2;2005年试验持续70d,试养鼠尾藻3×667m2,平均株长由13.0 cm生长至73.7 cm,鲜藻产量为2.88 kg/m2。试验结果表明鼠尾藻的劈叉式筏式养殖是可行的。     

镉诱导长江华溪蟹(Sinopotamon yangtsekiense)心肌细胞凋亡的研究

采用急性毒性实验方法,研究了不同浓度氯化镉(0、7.25、14.50、29.00、58.00和116.00mg/L)处理不同时间(1d、3d、5d和7d)对长江华溪蟹心肌细胞凋亡的影响。结果表明,低浓度组及染毒时间较短时镉对心肌的影响不明显,但随着染毒浓度的增加和时间的延长,心肌出现空泡变性、玻璃样变性、炎细胞浸润等病理现象,在染毒7d虽然观察到疑似的凋亡细胞,但凋亡率较低;荧光显微镜未观察到心肌细胞典型的凋亡细胞核形态学变化;琼脂糖凝胶电泳图谱未出现凋亡细胞所特有的梯状条带;流式细胞术检测结果显示镉处理组细胞凋亡率增加,但与对照组相比,无统计学意义(P>0.05);Caspase-3活性也没有显著性变化(P>0.05)。因此,在本实验所选取的浓度和时间范围内,镉未诱导长江华溪蟹心肌细胞发生细胞凋亡,这与本课题组前期研究中观察到的肝胰腺、精巢组织在染毒2d、7d发生细胞凋亡的情况明显不同,这可能与心脏组织的特殊性、不同组织对镉的积累量不同有关。     

Metallothioneins and cytosolic metals in Neomysis integer exposed to cadmium at different salinities

In the present study the induction of metallothioneins (MTs) and its relation to cytosolic metal concentrations (Zn, Cu and Cd) in the euryhaline crustacean Neomysis integer exposed to Cd at different salinities was studied. N. integer was exposed to the same free cadmium ion activity of 5.74 x 10(-9) mol l(-1) (i.e. 1/5 of the 96 h LC(50) value expressed as cadmium activity) in hypo-osmotic (5 psu), isosmotic (16 psu) and hyper-osmotic media (25 psu) for 7 days. In this way, the effect of salinity on cadmium speciation was eliminated and therefore the physiological effect of salinity on Cd accumulation and MT induction could be studied. The accumulation of cytosolic Cd in N. integer changed with salinity from 1.11+/-0.05 micromol l(-1) at 5 psu up to 1.43+/-0.17 micromol l(-1) at 25 psu. This could indicate that the physiological response of euryhaline estuarine invertebrates like N. integer to salinity changes can influence the rate of trace metal uptake from solution. While the salinity changes did not cause significant differences in cytosolic Zn concentrations (mean value of all tested salinities: 34.4+/-2.8 micromol l(-1)), an inverse relationship between salinity and cytosolic Cu concentration was observed. The highest concentration of 15.7+/-2.3 micromol Cul(-1) was determined at 5 psu and the lowest 10.9+/-1.4 micromol Cul(-1) at 25 psu. This could point to a possible relationship between the copper concentration and the hemocyanin metabolism in N. integer. This is the first time that differential pulse voltammetry method was applied to MT assays with N. integer. Although the exposure to Cd resulted in a higher Cd cytosolic concentration, no subsequent MT increase was detected. The significant positive correlation between MT levels and cytosolic Cu concentrations (Spearman correlation coefficient r(s)=0.356, p=0.009) implies a strong relationship between MT and Cu in N. integer.     

褐藻多酚含量的季节变化

褐藻多酚的季节变化研究具有重要的理论意义，对海黍子和鼠尾藻褐藻多酚的含量测定结果表明，褐藻多酚含量的季节变化范围分别在１．５￣３．１％之间以及０．８￣１．８％之间。另外，ＰＶＰ吸附率也有相应的变化，分别在５１￣６９％之间以及４１￣６３％之间。     

Role of metallothioneins in Cu and Cd accumulation and elimination in the g gill and digestive gland cells of mytilus galloprovincialis lam.

The data presented in this paper demonstrate that exposure of mussels to Cu (40 μg/liter) or Cd (200 μg/liter) for a period of 2 days is sufficient to induce Cu or Cd thioneins in the gills of the metal-exposed animals. The concentrations of Cu and Cd thioneins increase during the period of metal exposure (3–4 weeks), confirming the fact that metallothioneins play a fundamental role in the accumulation of these metals in the tissues examined (gills and digestive gland). Moreover, it has been demonstrated that when metal-loaded mussels are returned to the field for the recovery period, Cu is rapidly eliminated from the gill and digestive gland cells, showing a biological half-life of 9–10 days, whereas Cd is released much more slowly from the tissues, only about 50% of the total metal being lost after 4 months of detoxification. Interestingly enough, during the detoxification period the concentration of the metal bound to thioneins also follows the same pattern as the total metal present in the tissues, in fact the concentration of Cu thioneins decreases near the control level in about 24 days but, in contrast, the Cd-thionein concentration in the cytisol of the gill and digestive gland cells remaains high, decreasing only by about 40% at the end of the 4 month recovery period.The data presented also demonstrate that when Cd-loaded, detoxified mussels are exposed to Cu (100 μg/liter) for 6 h, the metal taken up by the gill cells is able to displace the Zn which is always present in the Cd-thionein fraction, but it does not, however, displace the Cd present. In this case also, period (20 days), whereas the Cd-thionein content decreases slightly. Such data seem to indicate that the metabolic characteristics of thioneins are closely related to the metal bound to them, particularly where the elimination rate of the metals from the cells is concerned.     

Bioenhancement of cadmium transfer along a multi-level food chain

Previous studies have shown that metal partitioned to a subcellular compartment containing trophically available metal (TAM) is readily available to predators and may be enhanced by increased binding of metal to heat-stable proteins (HSP - e.g., metallothioneins). The aim of the current investigation was to determine the influence of TAM on the trophic transfer of Cd along an experimental, three-level food chain: Artemia franciscana (brine shrimp)-->Palaemonetes pugio (grass shrimp)-->Fundulus heteroclitus (mummichog). P. pugio were fed for 7 days on A. franciscana exposed to Cd in solution (including (109)Cd as radiotracer) and subjected to subcellular fractionation or fed to F. heteroclitus. An HSP-driven increase in the percentage of Cd associated with TAM (TAM-Cd%) in A. franciscana exposed to 1 muM Cd resulted in a bioenhancement (i.e., a greater than linear increase with respect to A. franciscana exposure) of Cd trophic transfer to P. pugio. Increased dietary Cd exposure did not affect TAM-Cd% in P. pugio nor trophic transfer to F. heteroclitus.