Acute and chronic effects of clofibrate and clofibric acid on the enzymes acetylcholinesterase, lactate dehydrogenase and catalase of the mosquitofish, Gambusia holbrooki

The objective of this study was to investigate both acute and chronic effects of clofibrate and clofibric acid on the enzymes acetylcholinesterase (AChE), lactate dehydrogenase (LDH) and catalase (CAT) of the mosquitofish (Gambusia holbrooki). AChE, commonly used as a biomarker of neurotoxicity, was determined in the total head. LDH, an important enzyme of anaerobic metabolism, was quantified in dorsal muscle, and CAT, enzyme which has been used as indicative parameter of peroxisome proliferation, was determined in the liver. Furthermore, alterations of body and liver weight were also determined, through the calculation of the ratios final body weight/initial body weight, liver weight/final body weight, liver weight/gills weight and liver weight/head weight. Acute exposure of G. holbrooki to both clofibrate and clofibric acid induced a decrease in liver CAT activity, an increase in muscle LDH activity, while no effects were observed on AChE activity. However, chronic exposure did not alter significantly the enzymatic activities, suggesting reduced or null effects over these pathways, relative to effects reported in other species. No effects were observed for the calculated ratios, except a significant weight reduction for males chronically exposed to clofibrate.     

Energy metabolism and growth of Monoporeia affinis Lindstr. in the Northern Lake Krivoe (Karelia)

The physiological method for estimating production based on the relationship between growth and energy metabolism has been used for calculating model growth curves for the amphipod Monoporeia affinis and comparing them with the results of field studies. Calculations demonstrated that the physiological growth curves fit the results of field observations best under certain conditions which have zoological sense: the growth curve should reflect the actual maximum body size of an animal in the given population, the duration of the life cycle, and the time required for reaching the reproductive size.     

广州河涌水体中食蚊鱼肝脏性激素相关基因的表达水平研究

应用食蚊鱼细胞色素P450芳香化酶基因(CYP19α)、卵黄蛋白原基因(VTGα)和雌/雄激素受体基因(ERα/ARα)m RNA转录水平为指标,评价广州海珠涌和黄埔涌食蚊鱼受环境激素物质干扰产生雌/雄性化效应的现状。结果显示,海珠涌宝岗大道段(BG)、洪德路段(HD)和黄埔涌赤岗路段(CG)、苗艺路段(MY)采样点雌鱼性腺CYP19αm RNA表达水平显著降低。雌鱼肝脏VTGαm RNA的表达水平在夏冬两季CG点都显著升高,但在BG、HD和MY点的表达水平在冬季则显著下降;夏冬两季雌鱼雄激素受体ARαm RNA表达水平在各点都显著升高。雄鱼性腺CYP19αm RNA表达水平在各点都无明显差异,但CG点在夏季显著升高,而MY点在冬季则显著下降;雄鱼肝脏VTGα和雌激素受体ERαm RNA表达水平分别在各点都显著升高,但夏季MY点和冬季HD、MY各点无明显差异。结果表明,雌性食蚊鱼的VTGα和CYP19α基因受到不同程度的抑制,ERα较对照REF明显升高,表现出雄激素效应;雄性食蚊鱼VTGα和ERα转录水平较对照REF显著升高,CYP19α基因无显著性差异,表现出雌激素效应。生活在广州海珠涌和黄埔涌中的食蚊鱼受雌/雄激素物质干扰明显,表明河涌中环境激素污染严重。     

食蚊鱼(Gambusia afinis)cat、gapdh和gst基因的克隆及其在生态毒理学中的应用

根据Ensembl、Genbank登录的鱼类cat、gapdh和gst基因的CDS序列设计普通PCR扩增引物,寻找食蚊鱼的cat、gapdh和gst基因的c DNA片段,并根据定量引物设计要求设计出相应的SYBR Green I荧光定量RT-q PCR引物,建立了食蚊鱼cat、gapdh和gst基因的SYBR Green I荧光定量RT-q PCR方法。该方法在104~108数量级范围内有良好线性关系(R=0.999~1.000);熔解曲线显示扩增产物特异性良好,均为单一峰值;质粒标准品最高浓度与最低浓度的批内试验变异系数与批间试验变异系数均低于2%。利用该方法监测和评价环境污染物对水生生物的影响,选择了水体中常见典型药物污染物——双氯芬酸,研究其对食蚊鱼抗氧化基因表达的影响。结果表明,雌性食蚊鱼暴露在不同浓度双氯芬酸钠(0.005、0.05、0.5和5 mg·L-1)24 h后,其肝脏cat、gapdh和gst的mRNA呈现显著变化,相对于对照组,在低浓度0.005 mg·L-1时,cat与gst mRNA的表达量均有极显著上升(p0.01),而其它浓度均极显著下降(p0.01)。试验表明该方法具有快速、精确、灵敏度高的优点,可为利用该类小型鱼类的原位污染物的生物监测和生态毒理评价提供有力的技术支持。     

Sublethal Effects of Monocrotophos on Locomotor Behavior and Gill Architecture of the Mosquito Fish,Gambusia affinis

Subacute studies of monocrotophos [Dimethyl (E)-1-methyl-2-(methyl-carbamoyl) vinyl phosphate] on mosquito fish, Gambusia affinis, were carried out in vivo for 24 days to assess the locomotor behavior, structural integrity of gill, and targeted enzyme acetylcholinesterase (AChE, EC: 3.1.1.7) interactions. Monocrotophos (MCP) can be rated as moderately toxic to G. affinis, with a median lethal concentration (LC₅₀) of 20.49 ± 2.45 mgL^?1. The fish exposed to sublethal concentration of LC₁₀ (7.74 mgL^?1) were under stress and altered their locomotor behavior, such as distance traveled per unit time (m min^?1) and swimming speed (cm sec^?1) with respect to the length of exposure. Inhibition in the activity of brain AChE and deformities in the primary and secondary lamellae of gill may have resulted in failure of exchange of gases. The maximum inhibition of 95% of AChE activity was observed on days 20 and 24.

Morphological aberrations in the gills were also studied during exposure to the sublethal concentration of monocrotophos for a period ranging from 8 to 24 days. The extent of damage in gill was dependent on the duration of exposure. The findings revealed that inhibition in brain AChE activity and structural alteration in gill were responsible for altering the locomotor behavior of exposed fish.     

多氯联苯暴露对食蚊鱼CYP19ɑ 和VTGɑ 基因的表达及骨骼形态雄性化的影响

应用食蚊鱼细胞色素P450芳香化酶基因(CYP19%)和卵黄蛋白原基因(VTG%)m RNA转录水平为指标,研究微量多氯联苯(PCBs)长时间暴露对成年雌性食蚊鱼CYP19%基因和VTG%基因表达的影响,并评价其对雌性食蚊鱼产生的形态雄性化效应。采用静水暴露实验模式,分别设置0.08、0.4、2和10μg·L-1PCBs浓度,并设置对照组和平行组,定量测定14 d和28 d性腺CYP19%和肝脏VTG%m RNA表达水平的变化,以及对椎体脉棘发育的影响。暴露实验结果显示:1各PCBs浓度组(0.08、0.4、2和10μg·L-1PCBs)暴露均能抑制食蚊鱼CYP19%和VTG基因的表达,表明PCBs对食蚊鱼VTG%基因的抑制远大于对食蚊鱼CYP19%基因的抑制;20.4μg·L-1PCBs暴露显著地降低了食蚊鱼第15椎体脉棘的长度并降低第15、16椎体脉棘的L/D值,显示食蚊鱼出现骨骼形态雄性化,表明一定浓度的PCBs暴露会表现出抗雌激素效应。     

成都地区慈竹生长状况及其与环境因子关系的初步分析

通过对成都市城区边缘及郊区6个样地慈竹林竹株的实地观测和取样分析,发现成都市城区边缘及青白江区的慈竹普遍生长不良,不同竹龄竹株的高度和胸径都比无郊崇州市怀远的慈竹要小,发育不良竹株竹杆内硅的含量显著高,初步分析硅的过多积累可能是慈竹竹杆脆化的一个明显指标;发育不良的慈竹竹杆含水量也普遍比生长状况好的慈竹竹杆含水量高。从样地土壤样品分析发现,慈竹生长不良的样地土壤偏酸或者偏碱。成都市区的降水普遍偏酸,降水中过高的SO4^2-,NO3^-,Cl^-和F^-离子成分也可能是导致慈竹生长不良的环境因素。     

镉对食蚊鱼(Gambusia affinis)的急性毒性效应

以食蚊鱼(Gambusia affinis)为受试生物,采用半静水式急性毒性试验和亚急性毒性试验,分别测定Cd2+对食蚊鱼的半致死质量浓度(LC50)和超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、谷胱甘肽转硫酶(GST)活性及组织结构变化,检测镉对食蚊鱼的毒性作用,以探讨Cd2+在水环境中的毒性及食蚊鱼在环境科学研究中的应用.结果表明,Cd2+对食蚊鱼96 h的LC50为22.55 mg/L,属于高毒物质.相同Cd2+暴露质量浓度下,随暴露时间延长,SOD和CAT活性总体表现为先升高后降低的趋势,GST活性则总体表现为先升高后降低、且趋于稳定的趋势.Cd2+暴露后食蚊鱼肝和鳃组织会出现不同程度损伤.研究表明,Cd2+对食蚊鱼属于高毒物质,验证了食蚊鱼对化学品Cd2+的敏感性.     

雄烯二酮长期暴露对食蚊鱼肝脏生物转化酶系的影响

为了研究雄烯二酮(4-androstene-3,17-dione,AED)长期暴露对食蚊鱼(Gambusia affinis)肝脏7-乙氧基-3-异酚恶唑脱乙基酶(EROD)和谷胱甘肽硫转移酶(GST)的影响,分别利用不同浓度的AED(0.14、1.4、14、140 nmol·L-1和420 nmol·L-1)对食蚊鱼仔鱼进行180 d的水浴暴露,同时设丙酮和空白对照组,分别于第180天取样后测定肝脏的EROD和GST活性.结果表明,与对照组相比,AED对食蚊鱼雌性幼鱼的体重和体长均起到显著的抑制作用,对食蚊鱼雄性幼鱼的体重和体长的影响不明显,只有最高浓度起抑制作用.AED对食蚊鱼幼鱼EROD的抑制作用与暴露浓度呈显著的剂量关系.各浓度组AED对雌性食蚊鱼幼鱼和雄性食蚊鱼幼鱼GST活性的影响大致呈现出倒"U"曲线的趋势.