有机磷农药对缢蛏[Sinonovacula constricta （Lamarck）]

在实验室模拟缢蛏的生长环境，研究乐果和三唑磷对缢蛏的毒性效应，以气相色谱法测定缢蛏体内有机磷农药的含量，并通过光镜观察有机磷农药对缢蛏鳃和消化腺显微结构的影响，结果表明：缢蛏体内乐果和三唑磷的含量随着水体中有机磷农药的增加而增加，有很好的剂量一效应关系，但是无线性相关性，乐果和三唑磷对缢蛏鳃显微结构的影响是：鳃丝变短，鳃丝间隔和基底膜结缔组织增生，鳃孔、血管腔堵塞；不同的是：在乐果胁迫下，E皮细胞纤毛脱落严重，而三唑磷胁迫下，上皮细胞纤毛增生，乐果和三唑磷对缢蛏消化腺显微结构的影响主要表现为腺细胞界限模糊，腺泡水肿变形、部分坏死；结缔组织增生，细胞问质疏松，出现许多空泡；有机磷农药的浓度高时消化腺细胞变性、坏死，细胞质囊泡化，     

全氟辛烷磺酸（PFOS）急性暴露对斑马鱼鳃显微结构的影响

采用光镜和电镜的方法,探讨了高浓度全氟辛烷磺酸(PFOS)急性暴露对斑马鱼(Danio rerio)鳃显微结构的影响.暴露组PFOS浓度分别为0.5、1、2mg·L-1,同时设对照组,连续暴露7d,取鳃制备石蜡切片,进行光镜和扫描电镜观察.结果表明,7d后PFOS暴露组斑马鱼鳃部均有不同程度的损伤,石蜡切片上可观察到暴露组鱼鳃上皮细胞坏死脱落,鳃小片断裂或融合,并伴有鳃丝充血,且病变程度随PFOS浓度的升高而加重;扫描电镜下可观察到暴露组鱼鳃鳃丝表面分泌物增多,鳃丝细胞脱落或水肿,鳃小片前端细胞破损.高浓度PFOS急性暴露可在短期内对斑马鱼鳃组织造成严重损伤,且损伤程度存在剂量依赖效应.     

乐果降解菌LGX1的筛选及其降解特性研究

通过富集培养,从连续施用农药乐果的土壤中分离得到一株具有较强降解有机磷农药乐果能力的细菌菌株LGX1,通过菌落形态观察及细菌的16SrDNA测序,对其进行了鉴定,同时初步研究了其降解性能。结果表明：该菌株为蜡状芽孢杆菌（Bacillus cereus）,在接种量为20%,乐果初始质量浓度为100mg·L-1,外加碳源葡萄糖质量分数为2%,温度为35℃,初始pH值为4时该菌株对乐果的降解能力最强;并且能在以辛硫磷、毒死蜱和三唑磷为唯一碳源的基础盐培养基中生长,且均比在以乐果为唯一碳源的基础盐培养基中生长的OD600值要高,初步推断菌株LGX1对有机磷农药的降解有一定的广谱性。     

不同生物膜附着微塑料对文蛤鳃的毒性效应

近年来,微塑料在海洋环境中的广泛分布及其生物毒性效应与健康风险备受关注。天然海洋环境中,微塑料表面易被多种微生物定殖并形成生物膜,这可能影响微塑料的生物毒性,然而目前对其影响仍知之甚少。以海南典型双壳贝类文蛤（Meretrix lyrata）为受试动物,并以其重要的呼吸和滤食器官鳃为靶器官,研究生物膜对微塑料生物毒性的影响。通过将文蛤暴露在质量浓度为100μg·L-1的不同类型原始和生物膜附着的微塑料（聚苯乙烯PS、聚乙烯PE、聚对苯二甲酸乙二醇酯PET）环境中14 d,研究微塑料在文蛤鳃中的富集特征及其对鳃组织的病理损伤、抗氧化及免疫防御系统相关指标的影响。结果表明,原始和生物膜附着微塑料均能在文蛤鳃组织中富集,富集量随暴露时间延长而增加,且生物膜附着微塑料的生物富集效应更显著;微塑料富集导致鳃组织发生不同程度的机械损伤,出现鳃丝粘连、萎缩及断裂、鳃丝细胞坏死、纤毛脱落等病理现象,其中附着生物膜的微塑料比原始微塑料对鳃显微结构的损伤更为明显;微塑料胁迫造成超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和碱性磷酸酶（ALP）活性升高,谷胱甘肽（GSH）含量下降,丙二醛（MDA）含量无显...     

镉和铅对菲律宾蛤仔脂质过氧化及抗氧化酶活性的影响

为了研究亚致死浓度的重金属对海洋贝类的毒性效应,探讨其可能的作用机理,在实验生态条件下以菲律宾蛤仔(Ru-ditapes philip pinarum)为目标生物,采用半静态毒性实验方法,研究了不同浓度Cd2+(0.0948、0.237和0.474mg·L-1)和Pb2+(0.276、0.690和1.380mg·L-1)对菲律宾蛤仔鳃和消化腺组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性以及丙二醛(MDA)含量的影响。结果显示:(1)鳃和消化腺中的抗氧化酶及MDA的变化呈现出类似的趋势,在胁迫初期,各浓度处理组菲律宾蛤仔鳃和消化腺组织SOD和CAT与对照组相比活性都显著升高(P<0.01),呈现出明显的诱导效应,而MDA含量与对照组相比差异不显著(P>0.05);随着胁迫时间的延长,高浓度Cd2+(0.474mg·L-1)和Pb2+(1.380mg·L-1)处理组中SOD、CAT活性快速下降,与对照组相比差异显著;低浓度处理组中的抗氧化活性虽然也较对照组有所下降,但总体下降幅度不如高浓度组明显,并且所历暴露时间较长。各浓度处理组中MDA含量变化一致,均呈现出先升高后降低的趋势,且含量均高于对照组。(2)通过相关性分析,菲律宾蛤仔消化腺组织中的SOD活性与Cd2+浓度的相关性大于鳃组织,与Pb2+浓度的相关性则小于鳃组织;消化腺组织中的CAT活性与Cd2+、Pb2+浓度呈抛物线型相关,与鳃组织CAT活性相关性不十分显著。这说明消化腺组织中SOD活性对Cd2+的敏感性大于鳃组织,消化腺组织中CAT活性对Cd2+、Pb2+的敏感性大于鳃组织。因此,菲律宾蛤仔消化腺中SOD、CAT对水环境中的重金属反应敏感,且存在一定的剂量-效应关系,消化腺组织中SOD和CAT活性与其他敏感性指标一起可以作为指示早期海洋重金属污染的生物标志物。     

双酚A致文蛤鳃组织氧化损伤

双酚A(bisphenol A, BPA)是全球产量最大的化工产品之一,在塑料制品生产中得到广泛应用。然而,BPA的大量应用导致其在水环境中被频繁检出,对水生生物健康构成潜在威胁。相关研究证实BPA对水生生物的生殖和发育具有一定的毒性效应,但对双壳贝类毒性效应研究却十分有限。本研究将文蛤(Meretrix petechialis)分别暴露于1、10、100 μg·L^-1BPA中14 d,检测了文蛤鳃滤水率以及组织病理学变化,同时测定鳃组织过氧化氢(hydrogen peroxide,H₂O₂)和丙二醛(malondialdehyde,MDA)含量,以及过氧化氢酶(catalase,CAT)、谷胱甘肽-S-转移酶(glutathione-S-transferase,GST)、超氧化物歧化酶(superoxide dismutase,SOD)的活性,并对Nrf2/Keap1信号通路相关基因的表达水平进行分析。结果表明,BPA暴露干扰了文蛤鳃滤水率,导致文蛤鳃组织上皮细胞损伤和增生,并观察有纤毛和鳃丝减少的现象,且BPA浓度越...     

有机磷农药二元混合物联合效应评价新方法的研究

以敌敌畏、乐果联合作用于线虫的毒理学实验为基础,基于FH插值法理论,通过较少的实验数据建立有机磷农药二元混合物联合效应模型,求解作用效应表达式并绘制联合效应三维曲面图;基于合并用药分析公式,计算联合作用评价q值并绘制农药浓度与q值的联合作用评价三维曲面图,结果表明敌敌畏与乐果混合物联合作用不仅表现为相加作用,而且还在局部低浓度表现为拮抗作用,与多元统计分析结果一致。上述研究表明FH插值法理论可作为二元有机磷农药联合效应分析及评价的一种新方法。     

溴氰菊酯对菲律宾蛤仔体内酶活性和组织损伤的初步探索

采用不同质量浓度的溴氰菊酯(0.0070 mg·L~(-1)、0.014 mg·L~(-1)、0.020 mg·L~(-1)、0.027 mg·L~(-1))对菲律宾蛤仔进行20 d半静置染毒,测定不同时间淋巴液中乙酰胆碱酯酶(ACh E)和钠离子-钾离子-三磷酸腺苷酶(Na~+-K~+-ATPase)活性、鳃和肝脏中谷胱甘肽转硫酶(GST)活性的变化,并观察染毒20 d后鳃丝组织和消化盲囊组织的损伤情况。酶活性分析结果显示,与对照组相比,低浓度组(0.0070 mg·L~(-1))试验期间酶活性均无显著差异(P0.05);中浓度组(0.014 mg·L~(-1)、0.020 mg·L~(-1))淋巴液中ACh E和Na~+-K~+-ATPase均呈先激活后抑制的变化规律(P0.05),鳃和肝脏中GST活性均呈上升趋势(P0.05);高浓度组(0.027mg·L~(-1))淋巴液中ACh E和Na~+-K~+-ATPase、肝脏中GST活性在试验期间持续下降(P0.01),而鳃中GST活性呈先抑制后升高的趋势(P0.05)。研究表明,低中浓度的溴氰菊酯对菲律宾蛤仔体内的酶活性表现为先诱导后抑制,具有明显的时间、剂量效应;高浓度的溴氰菊酯对菲律宾蛤仔体内酶活持续抑制,且染毒浓度越高,组织细胞变异越显著,表现为鳃丝上皮细胞纤毛层萎缩、纤毛脱落,消化盲囊上皮细胞膨胀,出现包涵体样结构。     

煤矸石对鲫鱼体内微量元素含量及组织结构的影响

来自煤矸石中的微量元素进入水体后,会对水生生物产生影响。通过水池养殖试验,采用单因子水质标识(Pi)、ICP-MS和组织学石蜡切片技术,探讨不同水/煤矸石质量比率(300?1和300?7)条件下,煤矸石对鲫鱼(Carassius auratus)肌肉、鳃中微量元素含量及组织结构的影响。结果表明,试验持续一年后,(1)煤矸石未对上覆水产生营养盐污染,水质整体可达到地表水Ⅲ类标准,符合水产养殖渔业水域的标准。(2)随着水/煤矸石质量比率由300?1增至300?7时,鲫鱼肌肉和鳃中Zn、Cu、Cd、Pb的质量分数显著增加(P0.05);鳃对微量元素的富集能力大于肌肉;不同微量元素在肌肉和鳃中的质量分数分别表现为ZnCuAsPbCd和ZnCuPbAsCd。(3)水/煤矸石质量比率为300?1和300?7的试验组中,肌肉与鳃均出现组织学病变。肌肉组织中,肌纤维细胞核数目不断减少、分布离散程度加深,肌纤维出现坏死、结缔组织出现增生情况。鳃组织中,鳃丝间距增大,鳃丝软骨逐渐变薄,末端鳃小片出现脱落,鳃小片弯曲程度加深,呈无规则排列。肌肉和鳃的组织学病变程度随组织中微量元素的含量、煤矸石污染程度的加深而加重。研究结论可为采煤沉陷区湿地生物保护及周边居民的健康提供科学依据。     

重金属Cu2+,Pb2+和Zn2+胁迫对近江牡蛎(Crassostrea rivularis) SOD活性影响研究

为探讨将近江牡蛎(Crassostrea rivularis)抗氧化酶防御体系参数作为海洋重金属污染生物监测指标可行性,文章在实验室条件下,研究这三种重金属暴露对近江牡蛎(C.rivularis)鳃和消化腺组织SOD活性的诱导作用;实验结果表明:Cu2 ,Pb2 和Zn2 能诱导近江牡蛎(C.rivularis)腮和消化腺SOD的产生,但由于近江牡蛎(C.rivularis)腮和消化腺的结构和功能的不同,在重金属的诱导下,消化腺内的SOD活性要比腮的大;Pb2 和Zn2 诱导近江牡蛎(C.rivularis)鳃和消化腺组织SOD活性变化的剂量-效应均为抛物线型;Cu2 对近江牡蛎(C.rivularis)鳃组织SOD活性诱导曲线不呈抛物线型,而对消化腺组织SOD活性诱导的剂量-效应呈抛物线型;根据对SOD活性影响的强弱,三种重金属对近江牡蛎(C.rivularis)的毒性强弱顺序为Cu2 >Pb2 >Zn2 。在实验室条件下,近江牡蛎(C.rivularis)消化腺组织中的SOD活性可作为养殖水体重金属污染程度监测指标,但应用到实际养殖水体尚须进一步研究。     

Acid and alkaline phosphatase activities in the clam Ruditapes philippinarum

Acid and alkaline phosphatase activities have been partially characterized in Ruditapes philippinarum (Adams and Reeve, 1850). Two activity peaks at pH=4.5 and pH 10.5 were detected in the gill, digestive gland, mantle, siphon and foot. Acid phosphatase activity was higher than that of alkaline phosphatase. The highest activity for both enzymes was observed in the digestive gland and, in decreasing order, the gill, foot, siphon and mantle. Alkaline phosphatase activity was similar in the mantle, siphon and foot. K _m values were determined for both enzymes in the gill and digestive gland. Hill coefficients were near 1, indicating no allosteric behaviour for either enzyme in the two organs. The optimum temperature was the same for acid phosphatase in both gill and digestive gland (50 °C), while for alkaline phosphatase it differed for these two organs (gill, 40 °C; digestive gland, 35 °C). The apparent activation energy was obtained from Arrhenius plots, and ranged from 8.61 kcal/mol for alkaline phosphatase in the gill, to 10.84 kcal/mol for acid phosphatase in the digestive gland. The effects of metals (1 mM conc) on both enzyme activities were assayed in vitro. Hg strongly inhibited the enzyme activities in the gill and digestive gland, probably because of its affinity for the sulphydryl group. Histochemically, acid phosphatase in the gill was located in a granular form throughout the gill cells, but was undetectable in the ciliate epithelium of the gill filaments. Alkaline phosphatase was located in the gill skeleton. Clam size and phosphatase activities were inversely related, probably reflecting a decrease in shell deposition with inereasing size. As a function of season, both enzymes were present in lowest amounts in winter, when undifferentiated sex cells were predominant in the germinative epithelium, and highest in summer, when ripe individuals of both sexes were more frequent.     

Tissue and sub-cellular distribution of Fe,Cu, Zn and 210Po in the abalone Haliotis rubra

The tissue and sub-cellular distribution of Fe, Cu, Zn and the naturally occurring radionuclide polonium-210 was determined in the gastropod mollusc Haliotis rubra collected from Western Port Bay, Australia, between March and July 1988. The highest concentrations of the metals, with the exception of Cu, were found in the digestive gland. Copper was more uniformly distributed, with tissues that are more vasculated having higher concentrations. Ultrastructural examination of the digestive gland, gill and kidney showed dense membrane-bound granules within the cytoplasm. Elemental analysis of the granules by electron probe x-ray microanalysis indicated that the granules in the digestive gland and gill contained high concentrations of iron, with small amounts of copper and zinc. In contrast, the metal-containing granules in the kidney were predominantly composed of iron, copper and phosphorus, with variable contributions of sodium potassium, and calcium. Homogenisation and fractionation of the digestive gland by differential centrifugation confirmed that approximately 80, 10, 90 and 50% of the total homogenate Fe, Cu, Zn and ²¹⁰Po, respectively, sedimented at 1200xg. In the haemolymph, all the elements studied were associated with the soluble high molecular weight component of the serum, not with the amoebocytes. ²¹⁰Po was present in the mucus-secreting hypobranchial glands at about half the concentration found in gill tissue.     

The effect of copper and zinc on the metabolism of the mussel Mytilus edulis

The effects of copper and zinc on the metabolism of the mussel Mytilus edulis (L.) and its component tissues were studied. 500 ppm copper sodium citrate inhibited oxygen consumption of the whole animal and gill tissue, but no similar effect was observed on digestive gland tissue. 500 ppm zinc sodium citrate exerted no effect upon gill or digestive gland respiration, and neither metal salt affected the respiration of homogenates of gill, digestive gland or gonad. Direct observation of gill tissues during exposure to the metals revealed that 500 ppm copper sodium citrate caused inhibition of ciliary activity; exposure of tissues to 2 ppm Cu for 24 h resulted in only partial inhibition of the cilía. It is suggested that metabolic suppression noted in whole animals and gill tissues is due to the inhibition of an energy-consuming process such as ciliary activity rather than interference with respiratory enzyme systems.     

Characterisation and expression of four mRNA sequences encoding glutathione S-transferases pi,mu, omega and sigma classes in the Pacific oyster<Emphasis Type="Italic"> Crassostrea gigas</Emphasis> exposed to hydrocarbons and pesticides

Hydrocarbon and pesticide pollution in coastal ecosystems can disturb marine bivalve metabolism. In this study, we characterised four full-length cDNA sequences encoding glutathione S-transferases (GSTs) in the Pacific oyster Crassostrea gigas. A BLAST X search showed that these four sequences encode GSTs from four different classes: GST pi, sigma, mu and omega. A phylogenetic analysis of GST was made to determine the position of oyster GST compared to invertebrate and vertebrate sequences. We developed a semi-quantitative, multiplex RT-PCR to follow the expression of these four GSTs in tissues of oysters exposed to hydrocarbons and two pesticide treatments (glyphosate and a mixture composed of atrazine, diuron and isoproturon) under experimental conditions. Our results showed strong differential expression of these four GSTs that was both tissue specific as well as time and treatment dependent. We observed that expression levels were higher in digestive gland than in gill tissues in pesticide-exposed oysters. Furthermore, omega and mu class GST mRNA expression in the digestive gland might be useful as a possible marker of hydrocarbon exposure, while pi and sigma class GST mRNA expression in the digestive gland may be similarly useful as a marker of pesticide exposure in monitoring programmes.Communicated by S.A. Poulet, Roscoff     

Effects to perfluorooctane sulfonate (PFOS) on the mollusk Unio ravoisieri under laboratory exposure

To understand acute toxicity and oxidative stress of perfluorinated compounds in the freshwater ecosystems, we exposed freshwater mussels (Unio ravoisieri) to perfluorooctane sulfonate (PFOS), over a range of concentrations from 10 to 100?mg/L, in a laboratory experiment. Lethal concentration (LC50) was of about 65.9?mg/L after 96?h of exposure. The oxidative stress was assessed in gill and digestive gland of the freshwater mussels after 7 days of exposure to different nominal PFOS concentrations (C1=?2?mg/L, C2?=?6?mg/L and C3=?10?mg/L). C1 and C2 increased significantly (p?<?.05) the superoxide dismutase activity in both tissues compared, while the highest C3 decreased the enzyme activity. This implements an unfavourable response that highlights the excess of reactive oxygen species produced after contamination. The Catalase activity was also increased by about 40.05% and 66.63%, respectively, in gill and digestive gland after exposure to C3. The Malondialdehyde (MDA) level was increased in both gill and digestive gland in a concentration-dependent pattern. In contrast, the contamination of U. ravoisieri by PFOS did not affect the acetylcholinesterase activity in both organs (p?>?.005). These results provided information on potential biomarkers that could be effectively applied for the monitoring of freshwater ecosystem using indicator species such as U. ravoisieri.     

Metal Content in Selected Tissues and Shell of Pern A Virwis (L) From Pondicherry, East Coast of India

Mussels are good bioaccumulators of metals and have been used as indicators for environmental monitoring. in this study on P. viridis from Pondicherry coast, metal content (aluminium, lead, cadmium, copper and zinc) were analysed in selected tissues and shell nacre for a period of one year. the metal content shows that digestive gland accumulates higher concentrations of metal ions followed by gill, mantle and shell. of the different components (digestive gland, gill, mantle and shell nacre) of the organism, only shell nacre exhibited a significant relationship with ambient levels and therefore can be applied to temporal monitoring of metal contamination.     

Petroleum hydrocarbons in the marine bivalve Venus verrucosa: accumulation and cellular responses

Cellular and subcellular responses of the marine burrowing bivalve Venus verrucosa collected from the north-eastern coastline of Malta from January to June 1985, after exposure to petroleum hydrocarbons (PHC) were investigated. After long-term exposure to 100 gl^-1 of water-accomodated fractions (WAF) of crude oil, PHC were found to accumulate most rapidly in the digestive gland and then in the gills, with saturation levels being reached within 100 d of exposure in both cases. PHC accumulation, both in the mantle and muscle tissues, was more gradual and consistent throughout the whole exposure period. After 150 d of exposure, the digestive cells of the digestive gland were significantly reduced in height (atrophy) and exhibited reduced lysosomal membrane stability. After 144 h of exposure to higher concentration of PHC (820 and 420 gl^-1), several cytological effects were recorded, including an increase in cell volume and activity of gill mucocytes as well as in the number of haemocytes in gill blood sinuses. There was also evidence of damage to the epithelial lining of the foot, stomach and style sac and marked atrophy of the digestive cells of the digestive gland. The significance of such responses is discussed.     

Depuration of twelve trace metals in tissues of the oysters Crassostrea gigas and C. virginica

The depuration of 12 trace metals in the mantle, gill, digestive gland, and kidney of Crassostrea gigas and C. virginica was investigated under natural field conditions; oysters from a relatively contaminated environment (Redwood Creek in south San Francisco Bay) were transplanted to a relatively clean environment (Tomales Bay). In the transplanted oysters, the digestive gland and kidney depurated Cd, Cu, Hg, Ag, and Zn more readily than the mantle and gill. Other trace metals As, Fe, Mn, Ni and Se showed varying depuration patterns. The results for Cr and Pb were inconclusive, since initial concentrations were too low to follow any losses. Interspecific differences in trace metal depuration were observed. Biological half-lives for most trace metals were on the order of 23 to 60 d for C. gigas and on the order of 70 to 180 d for C. virginica.     

Accumulation,tissue distribution and elimination of 203HgCl2 and CH3 203HgCl in the tissues of the American oyster Crassostrea virginica

Oysters (Crassostrea virginica) were exposed for 3 days to mercury-203 labeled HgCl₂ or CH₃HgCl added directly to artificial seawater or added preconcentrated on the marine diatom Phaeodactylum tricornutum. The concentration of mercury in 5 tissues was measured for 45 days after mercury was removed from the ambient water. At the beginning of the depuration period, the highest concentrations of mercury in tissues were attained in: gill>digestive system>mantle>gonad>muscle in oysters exposed to water containing mercury; and in digestive system>gill>mantle> gonad>muscle in oysters fed labeled algae. This same distribution pattern is seen for both chemical forms of mercury. Although the initial pattern of accumulation was identical for both mercury compounds within each exposure group, the fate of the accumulated mercury was very different after 45-days depuration. In oysters accumulating mercury directly from seawater, inorganic mercury residues rapidly declined in gill and digestive tissue, but were slowly reduced in mantle, gonadal, and muscle tissue. This pattern was duplicated by oysters exposed to methyl mercuric chloride in seawater except that gonadal and muscle residues greatly increased during depuration. In oysters ingesting labeled P. tricornutum cells, mercuric chloride and methyl mercuric chloride residues rapidly declined in gill and digestive tissue, remained constant in the mantle, but sharply increased in gonadal and muscle tissue during depuration.