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Biomedical subjects

G D Wheelock

Publications and source records attributed to G D Wheelock.

5 recordsLinked to original sources
PubMed1992

Anti-P450lpr antiserum inhibits specific monooxygenase activities in LPR house fly microsomes.

Monooxygenase activity in microsomes from the LPR strain of house fly (Musca domestica L.) was inhibited by anti-P450lpr, and antiserum specific for house fly cytochrome P450lpr. Anti-P450lpr did not inhibit house fly cytochrome P450 reductase or rat cytochrome P450 monooxygenase assays, consistent with specific inhibition of P450lpr. Anti-P450lpr inhibited the ability of cytochrome P450 reductase to reduce carbon monoxide treated LPR microsomal cytochrome P450, up to 49% of the total, showing that inhibition of cytochrome P450 reduction is the major mechanism of inhibition. Anti-P450lpr inhibited 98% of methoxyresorufin-O-demethylase activity and all the benzo(a)pyrene hydroxylase activity in LPR microsomes, but none of the pentoxyresorufin-O-dealkylase activity. The antiserum partially inhibited ethoxyresorufin-O-dealkylase and ethoxycoumarin-O-dealkylase activity. These results demonstrate that methoxyresourfin-O-demethylase activity and benzo(a)pyrene hydroxylase activity are characteristic substrates for P450lpr activity in the LPR strain of house fly.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1991

Rapid isolation of a neurohormone from mosquito heads by high-performance liquid chromatography.

Methods were developed for the isolation of the egg development neurosecretory hormone, EDNH, from heads of the mosquito Aedes aegypti. This hormone stimulates ecdysone production by ovaries. Methods used for the successful isolation of insulin-like peptides from vertebrate tissues were modified to develop a four-step procedure involving extraction in acidified ethanol, precipitation by neutralization, followed by sequential separation on size-exclusion, ion-exchange and reversed-phase high-performance liquid chromatography columns.

Aedes↗
PubMed1991

Expression of cytochrome P-450lpr is developmentally regulated and limited to house fly.

Expression of house fly cytochrome P-450lpr was examined using immunoblotting in male and female adult LPR house flies, mixed sex adult house flies at 12 different ages, larvae, and pupae. P-450lpr was expressed in both male and female adult house flies. P-4501pr was clearly present in all adult stages examined, was barely detectable in pupae, and could not be detected in larvae. Thus, cytochrome P-450lpr is developmentally regulated and present in both sexes of house fly. Expression of cytochrome P-450, immunologically homologous to house fly cytochrome P-4501pr, was examined in other species using immunoblot analysis. Eleven animal species were tested in the orders Diptera, Hymenoptera, Lepidoptera, Orthoptera, Acari, and Rodentia, using microsomes in some species from both induced and noninduced animals or insecticide-resistant and susceptible strains. P-450lpr appears to be restricted to house flies, as none of these species contained cytochrome P-450 that reacted with antiserum to cytochrome P-450lpr.

Animals↗
PubMed1985

Egg maturation and ecdysiotropic activity in extracts of mosquito (Aedes aegypti) heads.

Blood-fed, decapitated female Aedes aegypti mosquitoes matured eggs when injected with an extract of heads, but non-blood-fed females did not. The response to head extract was optimal when the head was allowed to remain for 2 hr after feeding. A dose response to injected egg development neurosecretory hormone (EDNH) was observed in vivo that was similar to in vitro dose responses previously reported. Blood-fed decapitated females responded equally well to boiled or unboiled head extract. When blood-fed decapitated females were injected with head extract, ecdysteroid levels increased. Partial purification of head extract using high-pressure liquid chromatography yielded a fraction at 34% acetonitrile that showed egg maturation activity in vivo when injected into blood-fed decapitated females, and ecdysiotropic activity when incubated in vitro with ovaries. In addition, a fraction at 30% acetonitrile was found that showed activity in vivo but not in vitro and may be a precursor. Occasionally, the fraction at 37% acetonitrile showed activity in the in vitro assay but had little activity in vivo and may be a metabolite. These results suggest that the same hormone was being assayed in vivo and in vitro and is EDNH.

Aedes↗