| 9612934 |
Scharf ME, Neal JJ, Marcus CB, Bennett GW: Cytochrome P450 purification and immunological detection in an insecticide resistant strain of German cockroach (Blattella germanica, L.). Insect Biochem Mol Biol. 1998 Jan;28(1):1-9.
A German cockroach strain, Munsyana (MA) had 80-fold resistance to the pyrethroid insecticide cypermethrin, 4.5-fold greater total cytochrome P450 content and 2.5-fold greater cytochrome P450-mediated N-demethylation of 4-chloro-N-methylaniline compared to the susceptible Johnson Wax (JWax) strain. Immobilized artificial membrane high performance liquid chromatography (IAM-HPLC) of microsomal proteins from the MA strain enriched cytochrome P450 greater than 70-fold. Following purification, a single protein band of M (r) = 49,000 (P450 MA), was detected by silver-staining SDS PAGE gels. Antiserum to the purified protein from the MA strain (anti-P450 MA) was produced in mice. Anti-P450 MA inhibited cytochrome P450-mediated N-demethylation by 4-fold in both MA and JWax strains. In Western blots of microsomal proteins, anti-P450 MA differentiated single MA and JWax individuals by recognizing and M (r) 49,000 protein band in only the MA strain. In JWax cockroaches, the M (r) 49,000 band was only detectable in Western analysis following induction with pentamethylbenzene (PMB). PMB induction also increases N-demethylation 2.6 and 8.0-fold in the MA and JWax strains, respectively. These results are consistent with the hypothesis that insecticide resistance in the MA strain is due to over-expression of a cytochrome P450. |
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