分子全息QSAR方法预测苯衍生物对蝌蚪的急性毒性

采用半静态培养法测定了一系列苯衍生物对蝌蚪的12h致死毒性.应用分子全息QSAR方法构建了化合物的亚结构与毒性之间的定量模型,探讨了分子全息长度、碎片尺寸以及区分常数对模型质量的影响,并检验了模型的稳健性.结果显示,研究的51种苯衍生物的半致死毒性(12h log1 /LC₅₀,mol/L)分布在2.07～4.56之间.最优HQSAR模型以6～7为碎片尺寸,83为全息长度,6个主成分,Leave-One-Out交叉验证的r²_cv是0.849,最终的非交叉验证的拟合模型r² 为0.942 ,表明模型稳健性能良好,可用于预测苯衍生物的毒性.     

Toxicity of metals to tadpoles of the common Sunda toad,Duttaphrynus melanostictus

Tadpoles of the common freshwater Sunda toad, Duttaphrynus melanostictus (Amphibia, Bufonidae), were exposed for a 4-day period under laboratory conditions to copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminum (Al), and manganese (Mn) at various concentrations. Mortality was assessed and median times of death (LT₅₀) and lethal concentrations (LC₅₀) were calculated. LT₅₀ and LC₅₀ increased with the decrease in mean exposure times and concentrations for all metals. LC₅₀ (96?h) for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.03, 0.3, 4.2, 1.5, 8.8, 0.4, 1.9, and 39?mg?L^?1, respectively. Cu was the most toxic to D. melanostictus, followed by Cd, Fe, Al, Pb, Zn, Ni, and Mn (Cu?>?Cd?>?Fe?>?Al?>?Pb?>?Zn?>?Ni?>?Mn). Duttaphrynus melanostictus is similarly sensitive to these metals as other amphibian tadpoles.     

漳泽水库水体污染对黑斑蛙蝌蚪遗传毒性的野外调查研究

通过野外采集漳泽水库不同采样点的黑斑蛙蝌蚪,采用微核、核异常、彗星试验3种方法,研究了水体污染对蝌蚪红细胞微核率、核异常率和DNA断裂3种遗传毒性指标的影响。微核试验结果显示:各采样点红细胞微核率除泽头采样点外,均明显高于阴性对照(P0.01),其中水库入口店上采样点的微核率最高,为6.87‰,位于水库上、中、下游3个采样点的微核率逐渐下降,从大到小依次为:下韩(5.45‰)、台上(3.71‰)、泽头(2.33‰)。核异常试验结果显示:各采样点核异常率均明显高于阴性对照(P0.01),核异常率与微核率二者变化趋势趋于一致。彗星试验结果显示:各采样点红细胞尾长、尾矩与阴性对照相比差异均极显著(P0.01),尾长、尾矩的变化趋势与微核试验结果一致。对同样位于水库中游的采样点司徒和台上的4个指标进行多重比较分析发现:微核率、核异常率和彗星尾长差异均不显著(P0.05),而尾矩差异显著(P0.05)。综上可知,漳泽水库各采样点水体具有较高的遗传毒性,主要毒性作用为引起染色体(DNA)断裂;各采样点遗传毒性指标变化规律与水体污染物变化规律趋于一致,因此应用这3种方法可以有效地对水体遗传毒性进行检测。     

Group effect on individual locomotor activity of common toad (<Emphasis Type="Italic">Bufo bufo</Emphasis> L.) and brown frog (<Emphasis Type="Italic">Rana temporaria</Emphasis> L.) tadpoles

Different components of group effect on the locomotor activity of single common toad and brown frog tadpoles have been studied by estimating the length of their trajectories, the speed of movement, the number of crossings of experimental field zones, and the number and duration of stops. The results show that toad tadpoles are more active than frog tadpoles. Conspecific metabolites added to the water do not change the pattern of their locomotor activity. Under conditions of visual contact with other tadpoles, locomotor activity of a toad tadpole decreases, whereas that of a frog tadpole increases. Thus, tadpoles of the two amphibian species show species-specific behavioral responses to changes in experimental conditions.     

三氯生和三氯卡班对两栖动物蝌蚪的急性毒性

三氯生(TCS)和三氯卡班(TCC)是个人护理品中常用抗菌剂,在水体中普遍存在,但目前其对两栖动物的毒性研究仍较少。本研究以黑斑蛙蝌蚪和非洲爪蛙蝌蚪为受试生物,研究TCS和TCC对蝌蚪的急性毒性。将处于第一个蝌蚪发育期的黑斑蛙蝌蚪(Gosner 26期)和非洲爪蛙蝌蚪(NF 46期)分别暴露于系列浓度的TCS和TCC,测定其对蝌蚪的半数致死浓度(96 hLC_(50))。结果发现,TCS对黑斑蛙蝌蚪和非洲爪蛙蝌蚪的96 h-LC_(50)分别为441μg·L~(-1)和280μg·L~(-1);TCC对黑斑蛙蝌蚪和非洲爪蛙蝌蚪的96 h-LC_(50)为252μg·L~(-1)和217μg·L~(-1)。这些数据显示TCS和TCC对两种蝌蚪的毒性较高,且对非洲爪蛙蝌蚪毒性均略高于对黑斑蛙蝌蚪的毒性,整体来看TCC的毒性略高于TCS。