• Entomological Research
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• v.48 no.5
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• pp.400-404
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• 2018

In this study, we investigated resistance to the organophosphates chlorpyrifos in Tunisian populations of Culex pipiens pipiens. Three field populations were collected from Northern and central Tunisia between 2003 and 2005 and used for the bioassays tests. Our results registered moderate and high levels of resistance to chlorpyrifos which ranged from 33.8 to 111. The chlorpyrifos resistant populations were highly resistant to propoxur indicated an insensitive acetylcholinesterase 1 (AChE 1). The highest frequency of AChE 1 resistant phenotypes (64%) was recorded in the most resistant population (sample # 1). Bioassays conducted in the presence of synergists showed that not esterases were involved as the resistance mechanism to chlorpyrifos. However, CYP450 was partly involved in the resistance of the most resistant sample (# 1). Starch electrophoresis showed that three esterases were present in studied samples: A2-B2, A4-B4 and B12. Results are discussed in relation to the selection pressure caused by insecticide treatments.

• Korean journal of applied entomology
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• v.33 no.2
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• pp.74-80
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• 1994

The german cockroach, Blattello germanica L, populations were successively selected with dlchlowos for 11 generations. The resulting selected shin was investigated the resistance development. the cross resistance and the esterase actim@. In the dichlowos-selected(Rd) strain, the values of LCs increased 858 times more compared to the susceptible (S) strain. In the dich!o~vos-selected (Rd) strains, the cross-res~stance to chlorpyrifos, propoxur, fenvalerate and pemethnn showed 3.35. 4.09. 283 and 2.00 times. Esterase.activity of the Rd strain showed 1.33 times higher than that of the S strain in the filter paper test. In comparison of zymogram paitems of the estemse isoryme by thin agarose gel electrophoresis against the german cockroach, the S strain was separated by 4 bands uf esterase 3, 5, 6 and 8 bands and the Rd strain was separated by 6 bands of esterase 1, 2, 4, 5, 7 and 8 bands, and the resistant mechanisms of the Rd strain were considered as the 4 bands of esterase-1.2.4 and 7 bands except the common 2 bands of esterase.6 and 8 bands.

• Applied Biological Chemistry
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• v.29 no.3
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• pp.288-293
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• 1986

The washed fresh ginsengs packed with air, vaccum and nitrogen gas were irradiated at the levels of 1,2 and 3kGy gamma radiation and then stored at $4{\sim}5^{\circ}C$ for 90days to investigate the effects of gamma radiation on microbial inactivation, eelworm disinfestation and physicochemical changes. After a 90 day storage, $2{\sim}3kGy$ irradiated groups showed 20% of weight loss and 10% of rot while non-irradiated group 100% and 20% or more, respectively. Also the irradiated groups showed somewhat lower values of specific gravity, color density and hardness immediately after irradiation, thereafter higher value of them with storage time than those of non-irradiated group. The irradiation increased the yields of ginseng extract and crude saponins but no effects on the proximate composition and TLC and HPLC patterns of saponin. The food-borne microorganisms decreased in viable cell counts by $2{\sim}3$ log cycles with $2{\sim}3kGy$ radiation and the eelworms were completely disinfested with 1 kGy radiation.