The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surve...The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surveillance of protozoa′s respiratory metabolism with polarography technique showed a sensitive inhibition of its oxygen consumption, and at 20 μg/mL concentration the oxygen consumption was increased. For any malformation of morphology and perturbation in swimming trajectory, the neutral red coloration was done. This technique (neutral red) showed that there was a toxic effect of DFB on T. pyriformis, especially at the highest concentration; this toxicity was translated by rotatory swimming in same place and the increasing of coloration quantity in digestive vacuoles. Fig 5, Ref展开更多
Diflubenzuron (DFB, trade name dimilin 25 WP) is a chitin synthesis inhibitor widely used against forest insect pests in Algeria. Prior to implementation of these products as chemical agents for mosquito control, know...Diflubenzuron (DFB, trade name dimilin 25 WP) is a chitin synthesis inhibitor widely used against forest insect pests in Algeria. Prior to implementation of these products as chemical agents for mosquito control, knowledge on their potential effects on non-target organisms and its behaviour in water are needed. Therefore, the present study was focused on DFB and aimed to use an HPLC procedure developed previously in order to obtain information on its degradation in freshwater and its bioconcentration in adult females of the fish Gambusia affinis (Cyprinodondiformes, Poeciliidae), which is one of the best candidates for biological control programs against mosquitoes. The adult females were exposed to dimilin (initial concentration 312 ng a.i./ml) for 28 days and residues analysis determined at different exposure times (0, 7, 14, 21 and 28 days). The concentration of DFB in freshwater decreased with exposure time while the amount of residues detected at the surface of the fish body increased progressively to reach a maximum at day 14 (162.7 ± 14.0 ng/fish) and declined thereafter during the exposure period. In addition, DFB incorporation into body increased with decreasing DFB concentration in water at each exposure time. The following average distribution was noted at the end of experiment (28 days): about 33% of the applied concentration was detected on the surface of fish body and was recovered by simple rinsing, and about 67% was found inside the fish body. A degradation in water and surface of fish occurred starting day 14 during the experimental period. Thus, about 40% of the initial concentration was degraded in freshwater after 28 days. The results are discussed to develop a better understanding of the degradation of dimilin in water and their potential effect on non-target organisms for its application for controlling mosquito.展开更多
Conopomorpha sinensis is the dominant borer pest of Litchi chinensis(litchi)and Euphoria longan(longan)in China.Control of C.sinensis is difficult because of its cryptic life habit;thus,an effective ovicide could be b...Conopomorpha sinensis is the dominant borer pest of Litchi chinensis(litchi)and Euphoria longan(longan)in China.Control of C.sinensis is difficult because of its cryptic life habit;thus,an effective ovicide could be beneficial.The larvicidal effects of diflubenzuron(DFB)have been documented in many insect pest species.Therefore,DFB might be a useful ovicide to control C.sinensis.However,the detailed mode of action of DFB interference with insect molting and egg hatching is unclear.Thus,we studied alterations in expression of all genes potentially affected by DFB treatment using a transcriptome approach in 2-d-old C.sinensis eggs.Clean reads were assembled to generate 203455 unigenes and 440558 transcripts.A total of 4625 differently expressed genes,which included 2670 up-regulated and 1955 down-regulated unigenes,were identified.Chitin binding and chitin metabolic processes were among the most significant enriched pathways according to Gene Ontology analyses.Most of the genes that encode enzymes involved in the chitin biosynthesis pathway were unaffected,whereas genes that presumably encode cuticle proteins were up-regulated.Furthermore,altered expression patterns of 10 genes involved in the chitin biosynthesis pathway of C.sinensis embryos were observed in response to DFB treatment at different time points by quantitative reverse transcription polymerase chain reaction.We also observed abnormal development;there was reduced chitin content and modulated chitin distribution of newly hatched larvae,and altered egg hatching.Our findings illustrate an ovicidal effect of DFB on C.sinensis,and reveal more molecular consequences of DFB treatment on insects.展开更多
The effect of （1-（4-chlorophenyl）-3-（2,6-difluorobenzoyl）urea） insecticide - diflubenzuron - on wild type and white type fruit flies Drosophila melanogaster （Meigen, 1830） was studied. Adult insects were place...The effect of （1-（4-chlorophenyl）-3-（2,6-difluorobenzoyl）urea） insecticide - diflubenzuron - on wild type and white type fruit flies Drosophila melanogaster （Meigen, 1830） was studied. Adult insects were placed in vials with different concentrations of the insecticide in the nutrient （from 0.048 to 48 mg of diflubenzuron per 1 cm^3 of the nutrient）. In each case, the insects showed some mortality, which was concentrationdependant. When comparing both strains, we could observe different acute toxicities, with wild type being more resistant to diflubenzuron. However, subacute toxicity was similar within both strains. In both strains the prolonged exposure led to the extinction of the majority of the populations （〉 70%）. Although imagoes could freely copulate, we did not observe copulating fruit flies, and we did not find either eggs or larvae in any of the exposed groups. These results indicate that genetic mutation which leads to different eye colour can also affect resistance and survival of insects in pesticide-exposed areas.展开更多
文摘The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surveillance of protozoa′s respiratory metabolism with polarography technique showed a sensitive inhibition of its oxygen consumption, and at 20 μg/mL concentration the oxygen consumption was increased. For any malformation of morphology and perturbation in swimming trajectory, the neutral red coloration was done. This technique (neutral red) showed that there was a toxic effect of DFB on T. pyriformis, especially at the highest concentration; this toxicity was translated by rotatory swimming in same place and the increasing of coloration quantity in digestive vacuoles. Fig 5, Ref
文摘Diflubenzuron (DFB, trade name dimilin 25 WP) is a chitin synthesis inhibitor widely used against forest insect pests in Algeria. Prior to implementation of these products as chemical agents for mosquito control, knowledge on their potential effects on non-target organisms and its behaviour in water are needed. Therefore, the present study was focused on DFB and aimed to use an HPLC procedure developed previously in order to obtain information on its degradation in freshwater and its bioconcentration in adult females of the fish Gambusia affinis (Cyprinodondiformes, Poeciliidae), which is one of the best candidates for biological control programs against mosquitoes. The adult females were exposed to dimilin (initial concentration 312 ng a.i./ml) for 28 days and residues analysis determined at different exposure times (0, 7, 14, 21 and 28 days). The concentration of DFB in freshwater decreased with exposure time while the amount of residues detected at the surface of the fish body increased progressively to reach a maximum at day 14 (162.7 ± 14.0 ng/fish) and declined thereafter during the exposure period. In addition, DFB incorporation into body increased with decreasing DFB concentration in water at each exposure time. The following average distribution was noted at the end of experiment (28 days): about 33% of the applied concentration was detected on the surface of fish body and was recovered by simple rinsing, and about 67% was found inside the fish body. A degradation in water and surface of fish occurred starting day 14 during the experimental period. Thus, about 40% of the initial concentration was degraded in freshwater after 28 days. The results are discussed to develop a better understanding of the degradation of dimilin in water and their potential effect on non-target organisms for its application for controlling mosquito.
基金This study received financial support from the National Natural Science Foundation of China(31801800)the Natural Science Foundation of Guangdong Province(2020A151501960)+1 种基金Special fund for scientific innovation strategy-construction of high level Academy of Agriculture Science(R2019PY-QY001)Research System Foundation of Litchi and Longan in China(CARS-32-12).
文摘Conopomorpha sinensis is the dominant borer pest of Litchi chinensis(litchi)and Euphoria longan(longan)in China.Control of C.sinensis is difficult because of its cryptic life habit;thus,an effective ovicide could be beneficial.The larvicidal effects of diflubenzuron(DFB)have been documented in many insect pest species.Therefore,DFB might be a useful ovicide to control C.sinensis.However,the detailed mode of action of DFB interference with insect molting and egg hatching is unclear.Thus,we studied alterations in expression of all genes potentially affected by DFB treatment using a transcriptome approach in 2-d-old C.sinensis eggs.Clean reads were assembled to generate 203455 unigenes and 440558 transcripts.A total of 4625 differently expressed genes,which included 2670 up-regulated and 1955 down-regulated unigenes,were identified.Chitin binding and chitin metabolic processes were among the most significant enriched pathways according to Gene Ontology analyses.Most of the genes that encode enzymes involved in the chitin biosynthesis pathway were unaffected,whereas genes that presumably encode cuticle proteins were up-regulated.Furthermore,altered expression patterns of 10 genes involved in the chitin biosynthesis pathway of C.sinensis embryos were observed in response to DFB treatment at different time points by quantitative reverse transcription polymerase chain reaction.We also observed abnormal development;there was reduced chitin content and modulated chitin distribution of newly hatched larvae,and altered egg hatching.Our findings illustrate an ovicidal effect of DFB on C.sinensis,and reveal more molecular consequences of DFB treatment on insects.
文摘The effect of （1-（4-chlorophenyl）-3-（2,6-difluorobenzoyl）urea） insecticide - diflubenzuron - on wild type and white type fruit flies Drosophila melanogaster （Meigen, 1830） was studied. Adult insects were placed in vials with different concentrations of the insecticide in the nutrient （from 0.048 to 48 mg of diflubenzuron per 1 cm^3 of the nutrient）. In each case, the insects showed some mortality, which was concentrationdependant. When comparing both strains, we could observe different acute toxicities, with wild type being more resistant to diflubenzuron. However, subacute toxicity was similar within both strains. In both strains the prolonged exposure led to the extinction of the majority of the populations （〉 70%）. Although imagoes could freely copulate, we did not observe copulating fruit flies, and we did not find either eggs or larvae in any of the exposed groups. These results indicate that genetic mutation which leads to different eye colour can also affect resistance and survival of insects in pesticide-exposed areas.
