The acaricidal efficiency of fipronil alone and fipronil + methoprene compared to commercial fipronil and commercial fipronil + methoprene, applied by the epicutaneous route (spot-on) in dogs naturally infested with t...The acaricidal efficiency of fipronil alone and fipronil + methoprene compared to commercial fipronil and commercial fipronil + methoprene, applied by the epicutaneous route (spot-on) in dogs naturally infested with ticks, was assessed. Thirty dogs infested with high loads of ticks were used. On day 0, the dogs were divided into 5 groups of 6 animals each. Each animal was duly identified for individual and group monitoring. Treatments were made based on body weight according to manufacturer’s instructions. Group 1<span style="font-family:;" "=""> </span><span style="font-family:Verdana;">(G1) received 10.0% fipronil at a single dose of a pipette applied by epicutaneous</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">route in the base of the neck. G2 received 10% fipronil + 10% methoprene in single application similarly to G1. G3 was treated with 9.8% commercial fipronil as before mentioned. G4 received commercial 9.8% fipronil + 9.8% methoprene applied as in previous groups. G5 served as an infected untreated control. Animals were examined</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">by</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">thumb tick counts on days 0 (Treatment day), 3, 7, 14, 21 and 28. Efficacy was measured as a percentage of tick reduction in the treated groups relative to the untreated control. Results indicated an overall efficacy of 88.2%, 93%, 90.4% and 99.3%, respectively. There was no significant statistical difference between the treated groups (P < 0.05), neither in sex nor in weight. Engorged ticks were the most frequent, followed by the nymph group. However, by the end of the study these data were reversed due to the fact that only small larvae were found, which we interpreted came from engorged ticks that released their progeny before dying and a month later their offspring began to be observed present</span><span style="font-family:Verdana;">ly</span><span style="font-family:Verdana;"> and in full development. It is concluded that the combined formulations of fipronil + methoprene compared to fipronil applied alone, showed an additive effect against</span><span style="font-family:;" "=""> </span><i><span style="font-family:Verdana;">Rhipicephalus</span></i><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">sanguineus</span></i><span style="font-family:Verdana;"> ticks in naturally infested dogs kept in captivity.</span>展开更多
Degradation of pesticide residues （chlorpyrifos and fipronil） in rice from farm to fork and risk assessment for human health were studied to reveal the magnitude of risks faced by different populations of interest, ...Degradation of pesticide residues （chlorpyrifos and fipronil） in rice from farm to fork and risk assessment for human health were studied to reveal the magnitude of risks faced by different populations of interest, so that appropriate measures can be taken to control the risks, and to refine and update the human health risk assessment data while helping to determine the maximum residue level （MRL） value and harvest interval. Different dosages and treatments were used in field trials for the harvest residue test. Residue levels of postharvest-applied chlorpyrifos and fipronil during storage, exposure to sunlight, washing and boiling processes （boiled rice） were investigated for brown rice. The dietary exposure evaluation model （DEEM） was employed to estimate acute and chronic risks faced by different populations of interest. Percent of reference dose （POR） and margin of exposure （MOE） were calculated. A positive correlation between pesticide residues and the dosage and application frequency of pesticide was found in the field trials. Risk quotients indicate that multiple applications and double dosages of chlorpyrifos increase the risks to the entire population and prolong exposures to toxic concentrations. The concentration of pesticide residues decreased as a function of time, after sunlight exposure, storage, washing, and boiling processes. 91.6 and 96.16% degradations were achieved at the end of the experimental period for fipronil and chlorpyrifos, respectively. The boiling process played an important role in the degradation of these pesticides. The result of risk assessment to human health showed that harvest residues of chlorpyrifos in rice and acute dietary risks of chlopyrifos were of concern. The acute dietary （food only） risk estimated for chlorpyrifos as percent of acute population adjusted dose （aPAD） was frequently over 100%. The risk faced by boys under the age of 14 was higher than that for girls of the same age. For the subpopulation above age 14, the risk reversed. The chronic dietary risk from food alone showed that dietary exposures with fipronil were below the level of concern for the entire population, including children. The risk faced by rural residents was more serious than that for urbanite residents with the most sensitive populations being children and male residents who faced higher acute dietary risk than the other subpopulation groups. The harvest interval was found to be the critical measure to mitigate risk for all populations for safe rice eating. All risk levels decreased to acceptable levels when the harvest interval was extended to 14 d. To address these risks, a number of measures including reduced application rates （should not be doubled at single application）, increased retreatment intervals （longer than 7 d） and extended interval of harvest （at least 14 d） will be needed. The MRL for fipronil in rice is recommended to be 0.01 mg kg 1 in accordance with Codex （ref）.展开更多
By means of topical application, fipronil resistance was surveyed in the rice stem borer, Chilo suppressalis, from 12 diferent areas in east China from 2001 to 2004. The rice stem borers in most regions of Jiangsu and...By means of topical application, fipronil resistance was surveyed in the rice stem borer, Chilo suppressalis, from 12 diferent areas in east China from 2001 to 2004. The rice stem borers in most regions of Jiangsu and Anhui were still susceptible to fipronil. But in Wuxi, Jiangsu Province and Cixi, Zhejiang Province, their sensitivity became decreased （resistance ratios were 3.1 and 3.6, respectively）, and the medium level of resistance （resistance ratio was 21.2） was found in Cangnan, Zhejiang Province. So, it was still at the early stage for fipronil resistance development in this pest. Synergism experiments showed that piperonyl butoxide（PBO） had a little effect on both susceptible and resistant borers （synergism ratios were 1.1-1.2）. Though triphenyl phosphate （TPP） and diethyl meleate （DEM） had no effect on the susceptible borers, they had significant synergism on fipronil in the resistant population to fipronil （synergism ratios were 1.8 and 1.6, respectively）, indicating esterase and glutathion S-transferase may be involved in the resistance mechanism. Bioassay with currently used insecticides indicated that triazophos （because of high resistance）, trichlorphon and acephate had very low toxicity to resistant borers. But diazinon, pyridaphenthion, decamethrin and avermeatin showed high toxicity and had no cross resistance to fipronil, which could be considered as substitute insecticides in the resistance managment.展开更多
[ Objective] The paper was to explore the field efficacy of 22% fipronil FS against sugarcane stem borer and thrips （Baliothrips serratus Kobus ）. [ Method] The field trial was conducted by foliar spraying of 22% fi...[ Objective] The paper was to explore the field efficacy of 22% fipronil FS against sugarcane stem borer and thrips （Baliothrips serratus Kobus ）. [ Method] The field trial was conducted by foliar spraying of 22% fipronil FS and mixed broadcasting with fertilizer in 2014. [ Result ] Foliar spraying of 22% fipronil FS at the dose of 50 mIV667 m~ had the best control effect against sugarcane stem borer, and the control effect at 90 d post administration was 70.70%, significantly higher than that of control agent （61.86%）. Medium and high dose of 22% fipronil FS had better control effects against sugarcane thrips. [ Conclusion ] Considering control effects against sugarcane stem borers and thrips as well as sugarcane yield, it is recommended that 22% fipronil FS is sprayed at medium concentration （50 mL/667 m2 ）.展开更多
The indoor and field control effect of fipronil against termite was introduced, and the main influencing factors were analyzed, including traverse transfer of fipronil between termite individuals, temperature and prop...The indoor and field control effect of fipronil against termite was introduced, and the main influencing factors were analyzed, including traverse transfer of fipronil between termite individuals, temperature and proportion of termite exposed to fipronil, synergistic effect of other agents on fipronil, diffusion and degrada- tion of fipronil in soil. The effects of fipronil and metabolites on environment were elaborated.展开更多
The aim of this study was to draw a retrospective analysis on the lethality of Imidacloprid(Gaucho®)and Fipronil(Régent TS®)on Apis mellifera between 1992 and 2016 in France.Early monitoring reports in ...The aim of this study was to draw a retrospective analysis on the lethality of Imidacloprid(Gaucho®)and Fipronil(Régent TS®)on Apis mellifera between 1992 and 2016 in France.Early monitoring reports in the 1992-2002 period notified these two embedded insecticides to be at the origin of massive colony collapse disorders.Ecotoxicological analyses based on the LD50 of Imidacloprid and Fipronil highlighted their differential lethality by both contact(Imidacloprid:81 ng/honeybee vs.Fipronil:5.9 ng/honeybee)and ingestion(Imidacloprid:3.7 ng/honeybee vs.Fipronil:4.2 ng/honeybee),but failed to point Imidacloprid’s high solubility as a higher lethal agent.Chemical properties and action mode of these two insecticides originated neural disfunction in the case of Imidacloprid,and honeybee brood immune depression for Fipronil.Despite the conduction of these monitoring reports and laboratory researches,Fipronil was completely banned in 2005 but Imidacloprid only in 2016.展开更多
The residual effects of fipronil aqueous solutions(at mass concentrations of 10,30 and 50μg/L,respectively)on Eriocheir sinensis were investigated by the semi-static experiment method.The results showed that among th...The residual effects of fipronil aqueous solutions(at mass concentrations of 10,30 and 50μg/L,respectively)on Eriocheir sinensis were investigated by the semi-static experiment method.The results showed that among the treatment groups with different mass concentrations,the high mass concentration group contained fipronil at a significantly higher content in the crab legs than the low-mass concentration group,and also a significantly higher content in the body than the low mass concentration group.There were no significant differences in the content of fipronil between different parts of E.sinensis.The trend of fipronil-enriched parts was from the legs to the body to the gonads.Fipronil residue in E.sinensis had no sex selectivity,but it enriched faster in female E.sinensis than males.This study provides a certain reference for dealing with related fishery pollution accidents.展开更多
A rapid enzyme-linked immunosorbent assay(ELiSa)system for the detection of fipronil was studied.artificial antigens were synthesized through the glutaraldehyde method,and monoclonal antibodies were obtained via immun...A rapid enzyme-linked immunosorbent assay(ELiSa)system for the detection of fipronil was studied.artificial antigens were synthesized through the glutaraldehyde method,and monoclonal antibodies were obtained via immunization and fusion techniques.the concentration of the coated antigen and antibody and the reaction time were determined,and the recovery rate was determined by an ELiSa detection system.the cross-reaction rate of the antibody against fipronil metabolites was lower than 21.46%.the response time of the selected ELiSa system was 30 min shorter than that of the competitive ELiSa system.the iC20 to iC80 of the standard curve ranged from 0.139 to 1.433μg/L.the recovery rate of fipronil spiked in eggs was 76.7%-93.7%.this study provides support for the rapid ELiSa of fipronil.展开更多
The phenylpyrazole insecticide fipronil blocks resistance to dieldrin(RDL)γ-aminobutyric acid(GABA)receptors in insects,thereby impairing inhibitory neurotransmission.Some insect species,such as the diamondback moth(...The phenylpyrazole insecticide fipronil blocks resistance to dieldrin(RDL)γ-aminobutyric acid(GABA)receptors in insects,thereby impairing inhibitory neurotransmission.Some insect species,such as the diamondback moth(Plutella xylostella),possess more than one Rdl gene.The involvement of multiple Rdls in fipronil toxicity and resistance remains largely unknown.In this study,we investigated the roles of two Rdl genes,PxRdl1 and PxRdl2,in P.xylostella fipronil action.In Xenopus oocytes,RvRDL2 receptors were 40 times less sensitive to fipronil than P.vRDL1.P.vRDL2 receptors were also less sensitive to GABA compared with PxRDL1.Knockout of the fipronil-sensitive PxRdll reduced the fipronil potency 10-fold,whereas knockout of the fipronil-resistant PxRdl2 enhanced the fipronil potency 4.4-fold.Furthermore,in two fipronil-resistant diamondback moth field populations,PxRdl2 expression was elevated 3.7-and 4.1-fold compared with a susceptible strain,whereas PxRdl1 expression was comparable among the resistant and susceptible strains.Collectively,our results indicate antagonistic effects of PxRDLl and PxRDL2 on fipronil action in vivo and suggest that enhanced expression of fipronil-resistant PxRdl1 is potentially a new mechanism of fipronil resistance in insects.展开更多
Background:Naringin as a bioflavanone glycoside is abundant in citrus fruits,which since ancient times have been utilized as natural herbal treatments in traditional medicine.Naringin has potent antioxidant effect tha...Background:Naringin as a bioflavanone glycoside is abundant in citrus fruits,which since ancient times have been utilized as natural herbal treatments in traditional medicine.Naringin has potent antioxidant effect that may mitigate oxidative stress mediated cardiovascular and renal dysfunctions in mammalian systems.Objective:To explore probable modulatory actions of naringin on fipronil-induced cardio-renal dysfunctions.Methods:Twenty-four Wistar rats weighing 140±3.0 g were divided into four groups including normal control(saline),10 mg/kg Fipronil(FIP),FIP+100 mg/kg naringin,and 100 mg/kg naringin.Administration of naringin and fipronil was by oral gavage for 28 consecutive days.Urinalysis,blood pressure monitoring,biochemical assays,histology,and immunohistochemical evaluations were performed.Results:Naringin significantly(P<0.001)lessened blood pressure parameters,oxidative stress markers but significantly(P<0.001)heightened the systemic antioxidants.Likewise,naringin prevented fipronil-induced histopathological lesions such as congestion and cellular infiltration in cardiac and renal tissues.Moreover,naringin attenuated the immunohistochemical expression of troponin 1 and matrix metalloperoxidase-2 in cardiac tissues,but heightened angiotensin converting enzyme 2 expression in contrast to that of fipronil group.Conclusion:The observation in this study shows potent attenuation of fipronil-induced toxicity by naringin,through inhibiting processes related to oxidation and inflammation.展开更多
Fipronil and related analogs, a set of new noncompetitive GABAA receptor antagonists, were investigated using comparative molecular field analysis (CoMFA) to explore their three-dimensional quantitative structure-acti...Fipronil and related analogs, a set of new noncompetitive GABAA receptor antagonists, were investigated using comparative molecular field analysis (CoMFA) to explore their three-dimensional quantitative structure-activity relationships (3D-QSAR). Considering the structural complexity of molecules of fipronil and related analogs, three different alignments were performed in this paper. CoMFA model for housefly receptor yield the leave-one-out and cross-validated correlation coefficient q2 value of 0.511 and the conventional correlation coefficient r2 value of 0.997. The new compounds with higher activity would be designed from this model. CoMFA model for rat receptor was not successful using all these three alignments, the reason of which maybe that some molecules adopt different conformations for rat receptor.展开更多
文摘The acaricidal efficiency of fipronil alone and fipronil + methoprene compared to commercial fipronil and commercial fipronil + methoprene, applied by the epicutaneous route (spot-on) in dogs naturally infested with ticks, was assessed. Thirty dogs infested with high loads of ticks were used. On day 0, the dogs were divided into 5 groups of 6 animals each. Each animal was duly identified for individual and group monitoring. Treatments were made based on body weight according to manufacturer’s instructions. Group 1<span style="font-family:;" "=""> </span><span style="font-family:Verdana;">(G1) received 10.0% fipronil at a single dose of a pipette applied by epicutaneous</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">route in the base of the neck. G2 received 10% fipronil + 10% methoprene in single application similarly to G1. G3 was treated with 9.8% commercial fipronil as before mentioned. G4 received commercial 9.8% fipronil + 9.8% methoprene applied as in previous groups. G5 served as an infected untreated control. Animals were examined</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">by</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">thumb tick counts on days 0 (Treatment day), 3, 7, 14, 21 and 28. Efficacy was measured as a percentage of tick reduction in the treated groups relative to the untreated control. Results indicated an overall efficacy of 88.2%, 93%, 90.4% and 99.3%, respectively. There was no significant statistical difference between the treated groups (P < 0.05), neither in sex nor in weight. Engorged ticks were the most frequent, followed by the nymph group. However, by the end of the study these data were reversed due to the fact that only small larvae were found, which we interpreted came from engorged ticks that released their progeny before dying and a month later their offspring began to be observed present</span><span style="font-family:Verdana;">ly</span><span style="font-family:Verdana;"> and in full development. It is concluded that the combined formulations of fipronil + methoprene compared to fipronil applied alone, showed an additive effect against</span><span style="font-family:;" "=""> </span><i><span style="font-family:Verdana;">Rhipicephalus</span></i><i><span style="font-family:;" "=""> </span></i><i><span style="font-family:Verdana;">sanguineus</span></i><span style="font-family:Verdana;"> ticks in naturally infested dogs kept in captivity.</span>
基金supported by Jiangsu Pro-vincial Science and Technology Committee, China(BK2006167)
文摘Degradation of pesticide residues （chlorpyrifos and fipronil） in rice from farm to fork and risk assessment for human health were studied to reveal the magnitude of risks faced by different populations of interest, so that appropriate measures can be taken to control the risks, and to refine and update the human health risk assessment data while helping to determine the maximum residue level （MRL） value and harvest interval. Different dosages and treatments were used in field trials for the harvest residue test. Residue levels of postharvest-applied chlorpyrifos and fipronil during storage, exposure to sunlight, washing and boiling processes （boiled rice） were investigated for brown rice. The dietary exposure evaluation model （DEEM） was employed to estimate acute and chronic risks faced by different populations of interest. Percent of reference dose （POR） and margin of exposure （MOE） were calculated. A positive correlation between pesticide residues and the dosage and application frequency of pesticide was found in the field trials. Risk quotients indicate that multiple applications and double dosages of chlorpyrifos increase the risks to the entire population and prolong exposures to toxic concentrations. The concentration of pesticide residues decreased as a function of time, after sunlight exposure, storage, washing, and boiling processes. 91.6 and 96.16% degradations were achieved at the end of the experimental period for fipronil and chlorpyrifos, respectively. The boiling process played an important role in the degradation of these pesticides. The result of risk assessment to human health showed that harvest residues of chlorpyrifos in rice and acute dietary risks of chlopyrifos were of concern. The acute dietary （food only） risk estimated for chlorpyrifos as percent of acute population adjusted dose （aPAD） was frequently over 100%. The risk faced by boys under the age of 14 was higher than that for girls of the same age. For the subpopulation above age 14, the risk reversed. The chronic dietary risk from food alone showed that dietary exposures with fipronil were below the level of concern for the entire population, including children. The risk faced by rural residents was more serious than that for urbanite residents with the most sensitive populations being children and male residents who faced higher acute dietary risk than the other subpopulation groups. The harvest interval was found to be the critical measure to mitigate risk for all populations for safe rice eating. All risk levels decreased to acceptable levels when the harvest interval was extended to 14 d. To address these risks, a number of measures including reduced application rates （should not be doubled at single application）, increased retreatment intervals （longer than 7 d） and extended interval of harvest （at least 14 d） will be needed. The MRL for fipronil in rice is recommended to be 0.01 mg kg 1 in accordance with Codex （ref）.
基金the Key Technologies R&D Programme of the Tenth Five—Years Plan(2001BA509B08)Science and Technology Engineering Programme for Promoting Crop Yield(2004BA520Al5) Youth Foundation of Nanjing Agricultural University (020600247).
文摘By means of topical application, fipronil resistance was surveyed in the rice stem borer, Chilo suppressalis, from 12 diferent areas in east China from 2001 to 2004. The rice stem borers in most regions of Jiangsu and Anhui were still susceptible to fipronil. But in Wuxi, Jiangsu Province and Cixi, Zhejiang Province, their sensitivity became decreased （resistance ratios were 3.1 and 3.6, respectively）, and the medium level of resistance （resistance ratio was 21.2） was found in Cangnan, Zhejiang Province. So, it was still at the early stage for fipronil resistance development in this pest. Synergism experiments showed that piperonyl butoxide（PBO） had a little effect on both susceptible and resistant borers （synergism ratios were 1.1-1.2）. Though triphenyl phosphate （TPP） and diethyl meleate （DEM） had no effect on the susceptible borers, they had significant synergism on fipronil in the resistant population to fipronil （synergism ratios were 1.8 and 1.6, respectively）, indicating esterase and glutathion S-transferase may be involved in the resistance mechanism. Bioassay with currently used insecticides indicated that triazophos （because of high resistance）, trichlorphon and acephate had very low toxicity to resistant borers. But diazinon, pyridaphenthion, decamethrin and avermeatin showed high toxicity and had no cross resistance to fipronil, which could be considered as substitute insecticides in the resistance managment.
基金Supported by Special Project for Construction of China Agricultural Industry Research System(CARS-20-2-3)Special Fund for Agro-scientific Research in the Public Interest(200903004-41)Key Science and Technology Project of Agriculture in Guangxi Province(201414)
文摘[ Objective] The paper was to explore the field efficacy of 22% fipronil FS against sugarcane stem borer and thrips （Baliothrips serratus Kobus ）. [ Method] The field trial was conducted by foliar spraying of 22% fipronil FS and mixed broadcasting with fertilizer in 2014. [ Result ] Foliar spraying of 22% fipronil FS at the dose of 50 mIV667 m~ had the best control effect against sugarcane stem borer, and the control effect at 90 d post administration was 70.70%, significantly higher than that of control agent （61.86%）. Medium and high dose of 22% fipronil FS had better control effects against sugarcane thrips. [ Conclusion ] Considering control effects against sugarcane stem borers and thrips as well as sugarcane yield, it is recommended that 22% fipronil FS is sprayed at medium concentration （50 mL/667 m2 ）.
文摘The indoor and field control effect of fipronil against termite was introduced, and the main influencing factors were analyzed, including traverse transfer of fipronil between termite individuals, temperature and proportion of termite exposed to fipronil, synergistic effect of other agents on fipronil, diffusion and degrada- tion of fipronil in soil. The effects of fipronil and metabolites on environment were elaborated.
文摘The aim of this study was to draw a retrospective analysis on the lethality of Imidacloprid(Gaucho®)and Fipronil(Régent TS®)on Apis mellifera between 1992 and 2016 in France.Early monitoring reports in the 1992-2002 period notified these two embedded insecticides to be at the origin of massive colony collapse disorders.Ecotoxicological analyses based on the LD50 of Imidacloprid and Fipronil highlighted their differential lethality by both contact(Imidacloprid:81 ng/honeybee vs.Fipronil:5.9 ng/honeybee)and ingestion(Imidacloprid:3.7 ng/honeybee vs.Fipronil:4.2 ng/honeybee),but failed to point Imidacloprid’s high solubility as a higher lethal agent.Chemical properties and action mode of these two insecticides originated neural disfunction in the case of Imidacloprid,and honeybee brood immune depression for Fipronil.Despite the conduction of these monitoring reports and laboratory researches,Fipronil was completely banned in 2005 but Imidacloprid only in 2016.
基金Supported by Basic Scientific Research Fund of China Academy of Fishery Sciences(No.2018HYZD0605)National Aquatic Product and Safety Risk Assessment Project(No.GJFP2018009).
文摘The residual effects of fipronil aqueous solutions(at mass concentrations of 10,30 and 50μg/L,respectively)on Eriocheir sinensis were investigated by the semi-static experiment method.The results showed that among the treatment groups with different mass concentrations,the high mass concentration group contained fipronil at a significantly higher content in the crab legs than the low-mass concentration group,and also a significantly higher content in the body than the low mass concentration group.There were no significant differences in the content of fipronil between different parts of E.sinensis.The trend of fipronil-enriched parts was from the legs to the body to the gonads.Fipronil residue in E.sinensis had no sex selectivity,but it enriched faster in female E.sinensis than males.This study provides a certain reference for dealing with related fishery pollution accidents.
文摘A rapid enzyme-linked immunosorbent assay(ELiSa)system for the detection of fipronil was studied.artificial antigens were synthesized through the glutaraldehyde method,and monoclonal antibodies were obtained via immunization and fusion techniques.the concentration of the coated antigen and antibody and the reaction time were determined,and the recovery rate was determined by an ELiSa detection system.the cross-reaction rate of the antibody against fipronil metabolites was lower than 21.46%.the response time of the selected ELiSa system was 30 min shorter than that of the competitive ELiSa system.the iC20 to iC80 of the standard curve ranged from 0.139 to 1.433μg/L.the recovery rate of fipronil spiked in eggs was 76.7%-93.7%.this study provides support for the rapid ELiSa of fipronil.
基金supported by the National Key R&D Program of China(2018YFD0200300)the Project of Science and Technology in Guangdong Province(2018A030313188)+1 种基金the Natural Science Foundation of Guangdong Province(2017A030310490)the Research and Innovation Team of Key Technologies in Modern Agricultural Industry in Guangdong Province(2019KJ130).
文摘The phenylpyrazole insecticide fipronil blocks resistance to dieldrin(RDL)γ-aminobutyric acid(GABA)receptors in insects,thereby impairing inhibitory neurotransmission.Some insect species,such as the diamondback moth(Plutella xylostella),possess more than one Rdl gene.The involvement of multiple Rdls in fipronil toxicity and resistance remains largely unknown.In this study,we investigated the roles of two Rdl genes,PxRdl1 and PxRdl2,in P.xylostella fipronil action.In Xenopus oocytes,RvRDL2 receptors were 40 times less sensitive to fipronil than P.vRDL1.P.vRDL2 receptors were also less sensitive to GABA compared with PxRDL1.Knockout of the fipronil-sensitive PxRdll reduced the fipronil potency 10-fold,whereas knockout of the fipronil-resistant PxRdl2 enhanced the fipronil potency 4.4-fold.Furthermore,in two fipronil-resistant diamondback moth field populations,PxRdl2 expression was elevated 3.7-and 4.1-fold compared with a susceptible strain,whereas PxRdl1 expression was comparable among the resistant and susceptible strains.Collectively,our results indicate antagonistic effects of PxRDLl and PxRDL2 on fipronil action in vivo and suggest that enhanced expression of fipronil-resistant PxRdl1 is potentially a new mechanism of fipronil resistance in insects.
文摘Background:Naringin as a bioflavanone glycoside is abundant in citrus fruits,which since ancient times have been utilized as natural herbal treatments in traditional medicine.Naringin has potent antioxidant effect that may mitigate oxidative stress mediated cardiovascular and renal dysfunctions in mammalian systems.Objective:To explore probable modulatory actions of naringin on fipronil-induced cardio-renal dysfunctions.Methods:Twenty-four Wistar rats weighing 140±3.0 g were divided into four groups including normal control(saline),10 mg/kg Fipronil(FIP),FIP+100 mg/kg naringin,and 100 mg/kg naringin.Administration of naringin and fipronil was by oral gavage for 28 consecutive days.Urinalysis,blood pressure monitoring,biochemical assays,histology,and immunohistochemical evaluations were performed.Results:Naringin significantly(P<0.001)lessened blood pressure parameters,oxidative stress markers but significantly(P<0.001)heightened the systemic antioxidants.Likewise,naringin prevented fipronil-induced histopathological lesions such as congestion and cellular infiltration in cardiac and renal tissues.Moreover,naringin attenuated the immunohistochemical expression of troponin 1 and matrix metalloperoxidase-2 in cardiac tissues,but heightened angiotensin converting enzyme 2 expression in contrast to that of fipronil group.Conclusion:The observation in this study shows potent attenuation of fipronil-induced toxicity by naringin,through inhibiting processes related to oxidation and inflammation.
文摘Fipronil and related analogs, a set of new noncompetitive GABAA receptor antagonists, were investigated using comparative molecular field analysis (CoMFA) to explore their three-dimensional quantitative structure-activity relationships (3D-QSAR). Considering the structural complexity of molecules of fipronil and related analogs, three different alignments were performed in this paper. CoMFA model for housefly receptor yield the leave-one-out and cross-validated correlation coefficient q2 value of 0.511 and the conventional correlation coefficient r2 value of 0.997. The new compounds with higher activity would be designed from this model. CoMFA model for rat receptor was not successful using all these three alignments, the reason of which maybe that some molecules adopt different conformations for rat receptor.
