• Molecular & Cellular Toxicology
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• v.4 no.2
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• pp.132-137
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• 2008

Differential gene expression profiling was carried out in the hepatic tissue of medaka fish, Oryzias latipes, after exposure to an organophosphorus pesticide (OPP), Iprobenfos (IBP), a widely used pesticide in agri- and fish-culture, using a medaka cDNA micro array. Twenty six kinds of differentially expressed candidate genes, with 15 and 11 induced and repressed in their gene expressions, respectively, were associated with cytoskeleton (3.8%), development (7.7%), immune (7.7%), metabolism (30.8%), nucleic acid/protein binding (42.3%) and reproduction (7.7%). Of these genes, changes at the transcription level of five were re-evaluated by real-time quantitative PCR (qRT-PCR). Considering the known function of authentic genes, the effects of IBP on the biological activity and pathological aspects in medaka fish were discussed. The identified genes could be used as molecular biomarkers for biological responses to OPPs contamination in an aquatic environment.

• Applied Biological Chemistry
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• v.33 no.2
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• pp.133-137
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• 1990

The effects of soil environmental conditions on the rate of degradation of fungicide IBP (Iprobenfos, S-benzyl O, O-diisopropyl phosphorothioate) in the soils under flooded condintions were examined in the laboratory. IBP in soil was degraded more slowly under flooded conditions than under upland conditions. The degradation greatly varied among soils, and the degradation rate was negatively correlated with the content of soil organic matter. Degradation of IBP was influenced by the soil temperature and the amount of IBP applied. The rate of degradation in soil was remarkably inhibited by the amendment of rice straw but not affected by the treatment of mixed-fertilizer, and insecticide fenitrothion and herbicide butachlor. The degradation of IBP was assumed to be due to microorganisms, especially aerobic microbes, as no degradation was observed in sterilized soil.

• Korean journal of applied entomology
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• v.40 no.3
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• pp.265-271
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• 2001

Resistance mechanisms in the green peach aphid (Myzus persicae) resistant to imidacloprid were investigated. Imidacloprid residues on the aphid integuments decreased slowly as time passed with no significant difference between the susceptible and resistant strains. Residue in the aphid body increased in both strains with time elapse, and was slightly more in the susceptible strain. A higher metabolic rate of imidacloprid in the resistant strain can be expected by the fact that more amount of imidacloprid were excreted in the resistant strain than in the susceptible one. The activity of AChE was higher 1.4 times in the resistant strain than in the susceptible one, and imidacloprid did not inhibit AChE at all in both strains. Piperonyl butoxide (PBO) and iprobenfos (IBP) synergized imidacloprid activity. The mixtures of imidacloprid and PBO (1 : 1 and 1 : 5) caused 69.4- and 250-fold increase of imidacloprid toxicity against the aphid. Insecticide toxicity of the mixtures of IBP and imidacloprid (1 : 1 and 1 : 5) was also increased 227 and 80.6 times. Esterase activity when $\alpha$-naphtyl butyrate and $\beta$-naphtyl acetate were used as substrates was higher in the resistance strain than in the susceptible one. This means that P450 monooxygenase and esterase are responsible for the resistance to imidacloprid in this aphid strain.