Objectives:In this study we have evaluated the mutagenicity of organophosphate pesticides acephate, chlorpyrifos, and profenofos using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay with the mosquito Culex quinquefasciatus taken as an experimental model.Materials and Methods:Second instar larvae were treated with LC20 of each pesticide for 24 h and mutations induced in the sequence of mitochondrial COII gene (690bp) were studied from restriction patterns generated with AluI, PacI, and PsiI restriction endonucleases.Results:Variations in the number and size of digested fragments were recorded from treated individuals compared with controls showing that the restriction enzymes created a cut at different locations. In addition, sequences of COII gene from control and treated individuals were also used to confirm the RFLP patterns. From the sequence alignment data, it was found that mutations caused the destruction and generation of restriction sites in the gene sequence of treated individuals.Conclusion:This study indicates that all the three pesticides had potential to induce mutations in the normal sequence of COII gene and also advocates the use of PCR-RFLP assay as an efficient, rapid, and sensitive technique to detect mutagenicity of pesticides.

The present article deals with the polymerase chain reaction (PCR)-based genotoxicity evaluation of neonicotinoid pesticides, imidacloprid and thiamethoxam, by using the genome of a mosquito Anopheles stephensi taken as an experimental model. After treatment of the second instar larvae with LC20 of the pesticides for 24 h, the induced nucleotide sequence variations in the internal transcribed spacer 2 (ITS2) of freshly hatched unfed control and treated individuals was studied from the sequence alignment data and the mutations in the form of insertion, deletion and substitution of bases were recorded. Measurable differences, indicative of the genetic damage due to imidacloprid and thiamethoxam were observed when ITS2 sequences of control and treated individuals were compared. It was found that imidacloprid-treated individual had 8 deletions, 29 insertions, 18 transitions and 33 transversions, whereas thiamethoxam-treated individual had 10 deletions, 8 insertions, 47 transitions and 68 transversions.

Abstract:The present paper deals with the genotoxicity evaluation of profenofos by applying dominant lethal test (DLT) on Culex quinquefasciatus taken as an experimental model. For this, the males hatched from the larvae treated with LC 20 of pesticide were crossmated with normal females and the results were based on the number of hatched and unhatched eggs laid by these females. Mean percentage frequency of unhatched eggs was as low as 3.97 in the normal stocks as compared to treated stocks in which the frequency of unhatched eggs had increased to 9.50. The statistical analysis of the data from treated groups gave values of 9.50±1.35 as against 3.97± 0.38 in the control groups. Profenofos induced significant (p<0.05) dominant lethality.

Objectives:In this study we have evaluated the genotoxic potential of pesticides acephate and profenofos by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay with the mosquito Culex quinquefasciatus taken as experimental model.Material and Methods:Second instar larvae were treated with LC20 of each pesticide for 24 h and induced mutations in the sequence of mitochondrial 16S rRNA gene were studied from restriction patterns generated with PacI and PsiI restriction endonucleases.Results:Variations in the number and size of digested fragments were recorded from treated individuals compared with controls showing that the restriction enzymes created a cut at different locations. In addition, sequences of the 16S gene from control and treated individuals were also used to confirm the RFLP patterns. From the sequence alignment data, it was found that mutations caused the destruction and generation of restriction sites in the gene sequence of treated individuals.Conclusion:This study indicates that both the pesticides had significant potential to induce mutations in the 16S gene of Culex quinquefasciatus.

Indiscriminate use of pesticides in agricultural practices has developed its toxicity in humans and animals exposed to it. Malathion is a non-systemic insecticide belonging to organophosphate class. It is used in controlling Mediterranean flies, bugs, and aphids in fields. The present study was aimed to evaluate the malathion induced genotoxicity in Internal transcribed spacer, ITS 1 and 2 sequences of rDNA of mosquito, Anopheles stephensi. For this, second instar larvae of mosquito were exposed to 2.54 ppm (LC20) of malathion for an acute period of 24h. Post-treatment, larvae were allowed to develop into adults, and Internal transcribed spacer (ITS) sequences of rDNA were amplified by Polymerase chain reaction (PCR). PCR amplification revealed significant point mutations in form of transition, transversion, deletion and insertion in treated ITS 1 and 2 sequences compared to control. ITS 1 sequence showed deletion of 26 bases, insertion of 141 bases, and substitutions of 236 bases compared to control. While, treated ITS 2 sequence suffered 48 deletions, 54 insertions, and 117 substitutions of nucleotide compared to non-treated mosquito sequences. ITS 1 was found to be more affected by malathion toxicity with lowered GC content. Thus, present study details the toxicity of pesticide in the mosquito, Anopheles stephensi, contributing to the field of toxicology.