Objective: To evaluate the deltamethrin pyrethroid insecticides against Anopheles labranchiae, potential malaria vector in Tunisia.Methods: Six field populations of Anopheles labranchiae mosquitoes were collected from...Objective: To evaluate the deltamethrin pyrethroid insecticides against Anopheles labranchiae, potential malaria vector in Tunisia.Methods: Six field populations of Anopheles labranchiae mosquitoes were collected from six localities in Northern and Central Tunisia between October and November 2016.Different bioassays were performed to estimate the level of resistance in each collected population. Two synergists were used to estimate the involvement of detoxification enzymes in insecticide resistance.Results: All studied strains were resistant and the RR50 ranged from 12.5 in sample #1 to72.5 in sample #6. Synergist tests using piperonyl butoxide indicated the involvement of monoxygenases enzymes in the recorded resistance. In contrast, the increase of deltamethrin mortality was not significant in presence of S,S,sributyl phosphorothioate(0.8 < SR < 1.2), suggesting no role of esterases(and/or GST) in the resistance phenotype. The correlation recorded between mortality due to DDT and the LC50 of deltamethrin insecticide indicated an insensitive sodium channel affected by Kdr mutation(Spearman rank correlation, r =-0.59, P < 0.01).Conclusions: These results should be considered in the current mosquitoes control programs in Tunisia. The use of pesticides and insecticides by both agricultural and public health departments in Tunisia should be more rational to reduce the development of resistance in populations. Different insecticide applications should be implemented alternately.展开更多
[ Objective] The paper was to study the 24 and 48 h acute toxicity of common pyrethroid insecticides of eypermethrin and deltamethrin on Brachionus calyciflorus. [ Method ] With Guangzhou strain of B. colyciflorus as ...[ Objective] The paper was to study the 24 and 48 h acute toxicity of common pyrethroid insecticides of eypermethrin and deltamethrin on Brachionus calyciflorus. [ Method ] With Guangzhou strain of B. colyciflorus as test animal, the standard toxicity test method was used to carry out acute toxicity test, and LC50 of cypermethrin and deltamethrin on rotifer was determined using probit method. [ Result ] LC50 of cypermethrin on rotifer was 3 376.87 and 5.87 μg/L at 24 and 48 h, respectively, and those of deltamethrin on rotifer was 594.56 and 74.17 μg/L, respectively. [Condusion] Acute toxicity of cypermethrin and dehamethrin on rotifer at 24 and 48 h was different, LC50 of cypermethrin and deltamethrin on rotifer at 48 h was more sensitive to monitor the chemical pollutants in water body than LC50 at 24 h.展开更多
To understand the degradation and environmental fate of pyrethroids, the process of their photodegradation under simulated natural conditions was investigated. The results showed that the degradation process follows f...To understand the degradation and environmental fate of pyrethroids, the process of their photodegradation under simulated natural conditions was investigated. The results showed that the degradation process follows first-order kinetics. The degradation intermediates were identified with gas chromatography-mass spectrometry. A plausible mechanism was discussed to explain the process. Several influences on degradation process were investigated and reported such as the effects of initial concentration of pyrethroids, total time of light irradiation, solvents, and light source, as well as the effect of a few substances that exist in the environment. This study could be a good reference for the degradation of pyrethroids in practical circumstances.展开更多
Objective To study the metabolism of 14^C-deltamethrin in rats. Methods Rats were dosed orally and i.p. with a single dose of 14^C-deltamethrin （0.64 mg/Kg） body weight. The required dose was applied daily for 3 day...Objective To study the metabolism of 14^C-deltamethrin in rats. Methods Rats were dosed orally and i.p. with a single dose of 14^C-deltamethrin （0.64 mg/Kg） body weight. The required dose was applied daily for 3 days. At the end of the experiment, selected organs, such as liver, kidney, fat, intestine, and blood were excised for radioassay of 14^C-content. Results Deltamethrin was almost eliminated from the body within 1-3 days. The main portion of 14^C-residues was extracted from urine （38%, 32%） and feces （20%, 24%） with a little amount remained in various organs. Conclusion The elimination and distribution of 14^C-radioactivity in rats treated orally and intraperitoneally signify that deltamethrin is bioavallable in urine and feces.展开更多
文摘Objective: To evaluate the deltamethrin pyrethroid insecticides against Anopheles labranchiae, potential malaria vector in Tunisia.Methods: Six field populations of Anopheles labranchiae mosquitoes were collected from six localities in Northern and Central Tunisia between October and November 2016.Different bioassays were performed to estimate the level of resistance in each collected population. Two synergists were used to estimate the involvement of detoxification enzymes in insecticide resistance.Results: All studied strains were resistant and the RR50 ranged from 12.5 in sample #1 to72.5 in sample #6. Synergist tests using piperonyl butoxide indicated the involvement of monoxygenases enzymes in the recorded resistance. In contrast, the increase of deltamethrin mortality was not significant in presence of S,S,sributyl phosphorothioate(0.8 < SR < 1.2), suggesting no role of esterases(and/or GST) in the resistance phenotype. The correlation recorded between mortality due to DDT and the LC50 of deltamethrin insecticide indicated an insensitive sodium channel affected by Kdr mutation(Spearman rank correlation, r =-0.59, P < 0.01).Conclusions: These results should be considered in the current mosquitoes control programs in Tunisia. The use of pesticides and insecticides by both agricultural and public health departments in Tunisia should be more rational to reduce the development of resistance in populations. Different insecticide applications should be implemented alternately.
基金Supported by Natural Science Foundation of Education Department of Anhui Province(KJ2010B269,KJ2008A138,KJ2010A328)Municipal Research Project of Lu'an City Directly Commissioned to West Anhui University(2009LW026)~~
文摘[ Objective] The paper was to study the 24 and 48 h acute toxicity of common pyrethroid insecticides of eypermethrin and deltamethrin on Brachionus calyciflorus. [ Method ] With Guangzhou strain of B. colyciflorus as test animal, the standard toxicity test method was used to carry out acute toxicity test, and LC50 of cypermethrin and deltamethrin on rotifer was determined using probit method. [ Result ] LC50 of cypermethrin on rotifer was 3 376.87 and 5.87 μg/L at 24 and 48 h, respectively, and those of deltamethrin on rotifer was 594.56 and 74.17 μg/L, respectively. [Condusion] Acute toxicity of cypermethrin and dehamethrin on rotifer at 24 and 48 h was different, LC50 of cypermethrin and deltamethrin on rotifer at 48 h was more sensitive to monitor the chemical pollutants in water body than LC50 at 24 h.
基金supported by the State Key Laboratory of Environmental Chemistry and Ecotoxicology of China(No. KF2008-08)the Education Department of Hebei(No. ZH200805)
文摘To understand the degradation and environmental fate of pyrethroids, the process of their photodegradation under simulated natural conditions was investigated. The results showed that the degradation process follows first-order kinetics. The degradation intermediates were identified with gas chromatography-mass spectrometry. A plausible mechanism was discussed to explain the process. Several influences on degradation process were investigated and reported such as the effects of initial concentration of pyrethroids, total time of light irradiation, solvents, and light source, as well as the effect of a few substances that exist in the environment. This study could be a good reference for the degradation of pyrethroids in practical circumstances.
文摘Objective To study the metabolism of 14^C-deltamethrin in rats. Methods Rats were dosed orally and i.p. with a single dose of 14^C-deltamethrin （0.64 mg/Kg） body weight. The required dose was applied daily for 3 days. At the end of the experiment, selected organs, such as liver, kidney, fat, intestine, and blood were excised for radioassay of 14^C-content. Results Deltamethrin was almost eliminated from the body within 1-3 days. The main portion of 14^C-residues was extracted from urine （38%, 32%） and feces （20%, 24%） with a little amount remained in various organs. Conclusion The elimination and distribution of 14^C-radioactivity in rats treated orally and intraperitoneally signify that deltamethrin is bioavallable in urine and feces.
