水化电子e_(aq)~-对乙酰甲胺磷的作用

利用60Co-γ辐射降解有机磷农药乙酰甲胺磷的稀水溶液,以乙酰胆碱酯酶抑制率为指标,研究了不同吸收剂量下水化电子对乙酰甲胺磷稀水溶液辐照前后的毒性变化;并采用高效液相色谱、离子色谱、气-质联用等检测手段对降解产物进行了分析.结合溶液毒性变化和降解率、生成的无机离子浓度、降解产物结构分析等,初步推导了60Co-γ辐射降解过程中水化电子对乙酰甲胺磷的作用机理.     

Acephate-induced shortening of developmental duration and early adult emergence in a nontarget insect Drosophila melanogaster

Similar to several environmental monitoring studies, the present study used Drosophila melanogaster as a model nontarget organism to explore the interfering effects of an organophosphate (OP) insecticide acephate on insect life cycle parameters. Acephate, a common OP, is readily available in nature from agricultural sources as an environmental contaminant. Along with target pests, nontarget fruit flies also suffer exposure to such environmental chemical. To evaluate the effects of such exposure, initially, acute LC₅₀ of acephate for third instar larvae was investigated and found to be between 14 and 16 μg/ml. This information yielded the following experimental concentrations (0.5, 1.5, 2.5, 3.5, 4.5, and 5.5 μg/ml) of test chemical for evaluation of effect, if any, on the insect model. Results showed that mean larval duration of insect significantly decreased on treatment with acephate, whereas the mean pupal duration remained unaffected. Interestingly the decreasing trend was seen to persist in case of mean adult emergence, where treated flies emerged significantly earlier in comparison to controls. Thus, the study demonstrated that acephate-induced shortening of developmental time and early emergence in Drosophila melanogaster.     

Effect of acute exposure of acephate on hemocyte abundance in a non-target victim Drosophila melanogaster

Organophosphate insecticide acephate was tested to investigate effects on hemocyte abundance in a non-target dipteran insect Drosophila melanogaster. For this purpose, third-instar larvae were fed on four graded concentrations (2, 4, 6, or 8 μg/ml) acephate for a period of 12 and 24 hr (acute treatment). Control groups were simultaneously maintained for comparison. Relative proportions of plasmatocytes in hemolymph smear were found to fall with increasing concentrations of the test chemical. Similar decreasing trend in population of lamellocytes was also noted after 12 and 24 hr chemical exposure. In contrast to plasmatocytes and lamellocytes, crystal cell number was found to rise with increasing pesticide concentration. Several factors like oxidative stress, apoptosis induction, and mitotic failure might be the cause of reduced plasmatocyte and lamellocyte count. The elevated number of crystal cells in hemolymph smears is directly indicative of high melanin synthesis that assists larvae to combat chemical stress, since melanin is well known for its potential to minimize physical, chemical, and pathogenic stress.     

乙酰甲胺磷和汞单一及复合污染对黄瓜发芽及幼苗生长的影响

有机磷农药和重金属是目前我国土壤中较常见的污染物。本文以黄瓜种子为供试作物,研究了重金属汞与农药乙酰甲胺磷单一污染及复合污染对其发芽率以及幼苗生长的毒害效应。结果表明,Hg2+与乙酰甲胺磷单一污染及复合污染对黄瓜种子的发芽率、芽长和根伸长的生态毒性敏感程度依次为:根伸长>芽长>发芽率,Hg2+与乙酰甲胺磷单一污染及复合污染对黄瓜幼苗的毒害效应均较明显。复合污染对黄瓜种子发芽指标和幼苗生长的抑制效应表现为协同作用,其结果是复合污染的整体生态毒性效应增强。研究结果为进一步研究农药和重金属复合污染的生态毒性提供基础资料。     

乙酰甲胺磷对斜生栅藻的毒性及细菌降解研究

采用血球计数法测定斜生栅藻细胞数目,研究了乙酰甲胺磷对斜生栅藻的毒性作用,并通过藻类培养液中接种经过筛选得到的乙酰甲胺磷高效降解菌测定其对乙酰甲胺磷毒性的去除影响。研究结果表明,乙酰甲胺磷对斜生栅藻的抑制中浓度(EC50)大于159 mg/L,急性毒性为低毒。但进一步研究发现,在7 d后,EC50为174.68 mg/L,明显低于24 h的1 128.57 mg/L,存在亚慢性毒性。通过藻类培养液接种高效降解菌Y-6,乙酰甲胺磷对藻类的生长抑制程度减轻。     

六种农药对乙酰胆碱酯酶活性的体外毒性效应

通过体外毒性试验,研究乙酰甲胺磷、巴丹、高效氯氰菊酯、甲基硫菌灵、异菌脲和哒螨灵6种农药对乙酰胆碱酯酶活性的毒性效应。结果表明,在体外反应体系中, 6种农药均对乙酰胆碱酯酶活性有明显的抑制作用,其中乙酰甲胺磷对乙酰胆碱酯酶活性抑制率随着浓度增高先下降后上升, 1mg·L-1时抑制率最低,为10. 07%;甲基硫菌灵对乙酰胆碱酯酶活性抑制率随着浓度增高先上升后下降, 0. 125mg·L-1时抑制率最高,达60. 32%;巴丹、高效氯氰菊酯、异菌脲、哒螨灵对乙酰胆碱酯酶活性抑制率随浓度增高而上升。     

Changes in hematological profile of male albino rats after acephate administration

The present study was designed to evaluate the possible adverse effects of acephate, an organophosphate insecticide, on hematological parameters in male albino rats. Acephate was administered orally to rats at either 25, 50, or 75 mg/kg bwt/day for 30 days. Data showed a significant decrease in total erythrocyte count, hemoglobin concentration, and hematocrit value; however, an increase in total leukocyte count was noted. The levels of blood sugar and blood urea were significantly elevated when administered by acephate. There were no significant changes in mean corpuscular hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin concentration for all doses. Thus, obtained results collectively revealed that acephate administration produced significant alterations in hematological parameters in dose-dependent manner.     

ZnFe_2O_4/TiO_2光催化剂制备及乙酰甲胺磷降解性能研究

分别采用共沉淀法和溶胶-凝胶法制备了ZnFe2O4和掺杂ZnFe2O4的纳米级TiO2光催化剂,进行了XRD、TEM和UV visDRS表征,以卤素灯为光源对纳米TiO2降解水溶液中乙酰甲胺磷农药进行了研究。考察了反应液初始pH值、催化剂用量、H2O2用量对降解率的影响。实验结果表明,焙烧温度为400℃、掺杂量为0.5%的ZnFe2O4/TiO2纳米粉体降解效果最佳,在相同条件下,反应2h后农药降解率可比纯TiO2提高20%左右。正交实验优化了降解反应条件,在常温常压下,起始pH值为12、H2O2浓度为12mmol/L、催化剂浓度为0.5g/L、反应3h后,初始浓度为1.0×10-4mol/L的乙酰甲胺磷农药降解率可达61.2%。     

Entomotoxicity and biosafety assessment of PEGylated acephate nanoparticles: A biologically safe alternative to neurotoxic pesticides

This is a report of an experimental study on a nanoencapsulation of the organophosphate acephate. Acephate was encapsulated in polyethylene glycol, using a simple, easy-to-replicate method that required no special equipment or conditions. The nanoencapsulation (nanoacephate) was characterized and its bioefficacy as compared to the regular commercial acephate was tested. The biosafety of the new compound was also tested on a murine model. Our new nanoencapsulation scored over the regular variety on all counts. It was found to successfully incorporate the active pesticidal component, acephate and this compound retained greater functional integrity over time as a nanoencapsulation. It was significantly more efficacious than the regular variety. It was biosafe when tested on murine model. We have reason to believe that this nanoencapsulation would allow the use of an organophosphate in a more targeted manner, thereby making it a cost-effective and eco-friendly alternative to the regular variety in use now.     

2株乙酰甲胺磷降解菌的分离鉴定及降解特性研究

利用富集及驯化培养方法,从长期生产农药企业的废水处理系统、厂房周边污染的土壤和池水中,分离筛选出2株能够高效降解乙酰甲胺磷的菌株Y3、Y6。在形态特征和生理生化鉴定的基础上,对其16S rDNA序列进行了分析,并重点研究了它们对乙酰甲胺磷及其他农药的降解特性和抗性。结果表明,Y3、Y6分别为寡养单胞菌(Stenotrophomonas)和假单胞菌(Pseudomonas)。Y3、Y6在乙酰甲胺磷浓度分别为500 mg/L和1 000 mg/L,培养温度30℃,初始pH8,接种量为2.5%条件下,一周内可以将80%左右的乙酰甲胺磷矿化为磷酸根。外加葡萄糖及酵母膏对降解效率的研究表明,当酵母膏含量为1 g/L时,降解效果最理想;而外加葡萄糖的量,能相对抑制其对农药的降解。抗性实验显示,Y3、Y6均可在较高浓度的其他有机磷类及氨基甲酸酯类农药的普通培养基中生长,对其他农药的抗性也比较广泛。植物侵染实验显示,Y3、Y6对实验中的豆科、禾本科、十字花科及葫芦科植物不具备致病性,说明Y3、Y6环境安全性较强。