Evaluation of Pyrethroid Susceptibility in Culex pipiens of Northern Izmir Province, Turkey

Background: Mosquitoes, being a nuisance species, are considered as one of the most important species in public health control programs due to their role as a vector in mosquito-borne diseases observed in humans and animals. We evaluated the susceptibility status of Culex pipiens collected from northern Izmir, Turkey in 2011–16. Methods: Mosquito larvae, collected from three different locations in northern İzmir, were reared in the laboratory. Adult susceptibility bioassays were performed using the WHO insecticide-impregnated papers including deltamethrin 0.05%, permethrin 0.75%, α-cypermethrin 0.05% and cyfluthrin 0.15%. In addition, adult bioassays were performed after the pre-exposure to piperonyl butoxide (PBO) to determine the contribution of P450 detoxification enzymes to the phenotypic resistance. Results: In all of the three populations, high levels of resistance were observed (mortalities<63%) to all of the four pyrethroids. Different pyrethroids but with the same mode of action can exhibit significantly different phenotypic re­sistance in a single population. PBO bioassays also showed that P450 detoxification enzymes can have diverse effects on different pyrethroids. Conclusion: Using just one chemical in a class of insecticide can be misleading for resistance studies

Evaluation of Pyrethroid Susceptibility in Culex pipiens of Northern Izmir Province, Turkey

BACKGROUND

Mosquitoes, being a nuisance species, are considered as one of the most important species in public health control programs due to their role as a vector in mosquito-borne diseases observed in humans and animals. We evaluated the susceptibility status of Culex pipiens collected from northern Izmir, Turkey in 2011-16.

METHODS

Mosquito larvae, collected from three different locations in northern İzmir, were reared in the laboratory. Adult susceptibility bioassays were performed using the WHO insecticide-impregnated papers including deltamethrin 0.05%, permethrin 0.75%, α-cypermethrin 0.05% and cyfluthrin 0.15%. In addition, adult bioassays were performed after the pre-exposure to piperonyl butoxide (PBO) to determine the contribution of P450 detoxification enzymes to the phenotypic resistance.

RESULTS

In all of the three populations, high levels of resistance were observed (mortalities<63%) to all of the four pyrethroids. Different pyrethroids but with the same mode of action can exhibit significantly different phenotypic resistance in a single population. PBO bioassays also showed that P450 detoxification enzymes can have diverse effects on different pyrethroids.

CONCLUSION

Using just one chemical in a class of insecticide can be misleading for resistance studies.

Premalignant lesions of the kidney share the same genetics changes as conventional renal cell carcinoma

This study investigated the frequency of allelic imbalance (AI) in particular loci in conventional renal cell carcinoma tissue and premalignant lesions of the kidney. DNA from the tumor tissue, premalignant lesions and normal kidney tissue of radical nephrectomy specimens from 33 patients was obtained. It was amplified with a set of eight microsatellite markers, which are located on chromosomes 2, 3, 5, 8, 9, 11, 16, 17. AI in DNA samples was determined by analysis of the alteration in (CA)n repeats. The rates of AI in tumor tissue were found to be between 22.2% and 53.3% and in premalignant lesions between 11.1% and 40.0%. Premalignant lesions and tumor tissues in conventional renal cell carcinoma have the same genotypic changes in 50.0-87.8% (informative cases). These results suggest that the progressive accumulation of AI in areas of premalignant lesions may contribute to the development of renal cell carcinoma, representing an important molecular event in the multistep renal carcinogenesis cascade.