手性农药水胺硫磷对水生生物的对映体选择性毒理研究

发布时间：2018-10-12 20:33

【摘要】：手性农药的对映体在环境化学行为和生态毒理方面显示出的选择差异性,在人和动物体内普遍存在。水胺硫磷(isocarbophos,ICP)属有机磷农药中的一种,是一硫代磷酰胺类的杀虫、杀螨剂,被广泛应用在农业上。水胺硫磷是手性化合物,但关于水胺硫磷不同对映体的毒性研究报道的文献有限。本课题前期工作探讨了丙酮溶剂对水华微囊藻(Microcystis flos-aquae)和蛋白核小球藻(Chlorella pyrenoidsa)的光合活性影响,找到敏感藻类及其最大无观察效应值,为手性农药毒理研究提供更可靠的数据依据。课题组将手性农药水胺硫磷进行拆分,得到单一对映体,通过测定水胺硫磷对水华微囊藻叶绿素a含量和光合作用的相关参数,水华微囊藻的抗氧化酶活性和MDA含量,以及大型蚤(Daphnia magna)的抗氧化酶活性和MDA含量,揭示水胺硫磷对水生生物的毒性影响,阐述两种对映体对水生生物毒性的选择性差异,从而为手性农药的环境安全和人体健康风险评价提供技术支持和科学依据。实验结果表明:(1)丙酮对水华微囊藻和小球藻的NOEC值分别为0.5%和0.05%,说明水华微囊藻对丙酮更为敏感。(2)在测定水胺硫磷及其对映体对水华微囊藻叶绿素a含量及光合活性的毒性实验中发现,(+)-ICP的毒性最强;Rac-ICP次之,(-)-ICP毒性最弱。(+)-ICP降低了水华微囊藻叶绿素a的含量,同时也抑制了水华微囊藻的光合活性,降低了藻细胞的光能利用率、最大电子传递速率以及强光耐受能力;而(-)-ICP和Rac-ICP则促进了光系统II的电子传递和光能利用率,提高了光合活性,使藻细胞对强光耐受能力增强。故这一结果可以说明,手性水胺硫磷对水华微囊藻细胞叶绿素a含量及光合作用的影响均存在显著的对映体选择性。(3)水胺硫磷对水华微囊藻产生的氧化损伤效应的实验结果显示了手性水胺硫磷显著的对映体差异。在暴露期间,Rac-,(+)-和(-)-ICP三者均未引起水华微囊藻细胞膜的脂质过氧化。但(+)-ICP处理组的MDA含量高于(-)-ICP,并且对SOD和CAT酶活性的影响存在“低促高抑”的现象。(-)-ICP处理组对SOD酶活性无影响,对CAT酶活性也存在“低促高抑”,但程度没有(+)-ICP处理组明显。(4)水胺硫磷对大型蚤产生的氧化损伤效应结果显示了显著的对映体差异。高浓度(2.5~20μg/L)下的处理组,(+)-ICP导致大型蚤体内脂质过氧化,(-)-ICP和ICP的MDA含量则明显低于空白组,无脂质过氧化现象。在各浓度处理下,(-)-ICP的SOD酶活性均大于ICP和(+)-ICP。而浓度在2.5~20μg/L时,(+)-ICP的CAT酶活性要大于ICP和(-)-ICP。
[Abstract]:Enantiomeric enantiomers of chiral pesticides show different selection in environmental chemical behavior and ecotoxicology, which are common in humans and animals. Isocarbophos,ICP is a kind of organophosphorus pesticide. It is an insecticide and acaricidal agent of phosphorothioamides, which is widely used in agriculture. Water sulphos are chiral compounds, but there is limited literature on the toxicity of different enantiomers. The effects of acetone solvent on photosynthetic activity of microcystis Shui Hua (Microcystis flos-aquae) and Chlorella Proteinus (Chlorella pyrenoidsa) were studied in this paper. The sensitive algae and its maximum non-observed effect were found, which provided a more reliable data basis for the study of chiral pesticide toxicology. A single enantiomer was obtained by separating the chiral pesticide, glyphosate. The contents of chlorophyll a and photosynthesis of microcystis Shui Hua, the antioxidant enzyme activity and the content of MDA were determined by determining the content of chlorophyll a and photosynthesis of microcystis Shui Hua. The antioxidant enzyme activity and MDA content of (Daphnia magna) revealed the toxicity of sulphos to aquatic organisms, and the selectivity of the two enantiomers to aquatic organisms was discussed. It provides technical support and scientific basis for environmental safety and human health risk assessment of chiral pesticides. The results showed that: (1) the NOEC values of acetone to microcystis Shui Hua and Chlorella microcystis were 0.5% and 0.05, respectively, which indicated that Shui Hua microcystis were more sensitive to acetone. (2) the contents of chlorophyll a and photosynthesis of Sac_person2# microcystis were determined by spectrophot2#. In the active toxicity test, () ICP was the most toxic, Rac-ICP was the second, and (-) ICP was the weakest. () ICP, which decreased the content of chlorophyll a in microcystis Shui Hua. At the same time, it also inhibited the photosynthetic activity of microcystis Shui Hua, decreased the utilization rate of light energy, the maximum electron transfer rate and the ability of strong light tolerance of algal cells, while (-)-ICP and Rac-ICP promoted the electron transport and light energy utilization of II in the light system. The photosynthetic activity was increased, and the ability of algal cells to strong light tolerance was enhanced. So this result shows that, There was significant enantioselectivity on chlorophyll a content and photosynthesis in microcystis cells of Shui Hua. (3) the oxidative damage effect of isocyanidophos on Sac_person1# microcystis showed chiral effect. There is significant enantiomeric difference in sulphos. During exposure, Rac-, ()-and (-)-ICP did not induce lipid peroxidation of microcystis cell membrane. However, the content of MDA in (-)-ICP treatment group was higher than that in (-)-ICP, treatment group, and the effect on the activity of SOD and CAT enzyme was "low promoting high inhibition". (-)-ICP treatment group had no effect on SOD enzyme activity, and "low promoting high inhibition" on CAT enzyme activity. But the degree was not obvious in ()-ICP treatment group. (4) the oxidative damage effect of siderophos on flea Magna showed significant enantiomeric difference. At high concentration (2.5 渭 g / L), () ICP resulted in lipid peroxidation in flea, and the MDA contents of (-) ICP and ICP were significantly lower than those of control group, and there was no lipid peroxidation. The SOD enzyme activity of (-)-ICP was higher than that of ICP and ()-ICP. under different concentrations. The CAT activity of, ()-ICP was higher than that of ICP and (-)-ICP. at the concentration of 2.5 渭 g / L and 20 渭 g / L.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X171.5;X592

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