Genes controlling malathion resistance in a laboratory-selected population of Drosophila melanogaster

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 844-853 ◽  
Author(s):  
D. R. Houpt ◽  
J. C. Pursey ◽  
R. A. Morton

The chromosomal locations of several genes responsible for increased malathion resistance in a laboratory-selected population of Drosophila melanogaster have been determined. These genes appear to be involved in the regulation of microsomal cytochrome P-450. A major gene on chromosome 2 (2-64) and at least two genes on chromosome 3 (near 3-58) control increased mixed function oxidase activity, and both larval and adult malathion resistance. Although the chromosome 2 locus was not associated with a significant increase in cytochrome P-450 content, SDS polyacrylamide gel electrophoresis of microsomal proteins detected increased silver staining of a polypeptide having a relative molecular mass (Mr) of about 52 000. Microsomes from strains carrying the chromosome 3 factors for resistance contained more cytochrome P-450 and increased amounts of two heme-staining protein bands (Mr = 50 000 and 54 000). The genes regulating these proteins were closely linked to striped at 3-62 and probably identical to the loci responsible for malathion resistance and increased mixed function oxidase activity. Other R genes on both chromosomes 2 and 3 as well as target resistance were required for the full expression of malathion resistance in the selected Drosophila population. Exposure of this Drosophila melanogaster population to malathion selected a polygenic system for the oxidative metabolism of insecticide.Key words: insecticide resistance, mixed-function oxidase, cytochrome P-450, Drosophila melanogaster.

1976 ◽  
Vol 154 (2) ◽  
pp. 433-438 ◽  
Author(s):  
J T. Wilson ◽  
T C. Spelsberg

Adult male rats were subjected either to sham operation or to hypophysectomy and adrenalectomy and maintained for a total of 10 days before treatment with growth hormone. Results of the early effects of growth hormone on the activities of the mixed-function oxidases in rat liver over a 96h period after growth-hormone treatment are presented. 2. Hypophysectomy and adrenalectomy result in decreased body and liver weight and decreased drug metabolism (mixed-function oxidases). Concentrations of electron-transport-system components are also decreased. 3. In the hypophysectomized/adrenalectomized rats, growth hormone decreases the activities of the liver mixed-function oxidases and the cytochrome P-450 and cytochrome c reductases, as well as decreasing the concentration of cytochrome P-450 compared with that of control rats. Similar but less dramatic results are obtained with sham-operated rats. 4. It is concluded that whereas growth hormone enhances liver growth, including induction of many enzyme activities, it results in a decrease in mixed-function oxidase activity. Apparently, mixed-function oxidase activity decreases in liver when growth (mitogenesis) increases.


1980 ◽  
Vol 188 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Maria J. Obrebska ◽  
Peter Kentish ◽  
Dennis V. Parke

An intraperitoneal dose of CS2 (500mg/kg) to male rats resulted in loss of liver microsomal mixed-function-oxidase activity (85% loss of biphenyl 4-hydroxylase), followed by denaturation of liver cytochrome P-450 to cytochrome P-420, and degradative loss of both cytochromes (50% loss). Losses of NADPH–cytochrome c reductase (20%) and cytochrome b5 were considerably less. Intraperitoneal administration of CS2 (100mg/kg) to rats pretreated wtih phenobarbitone or 3-methylcholanthrene resulted in similar losses, but the rate of destruction was greater with cytochrome P-450 than with cytochrome P-448. At 12h after intraperitoneal injection of CS2 to non-pretreated rats, a new cytochrome (P-448) appeared. Rat liver microsomal preparations incubated with CS2 in the presence of NADPH and O2 resulted in loss of cytochrome P-450 and mixed-function-oxidase activity directly related to the concentration of CS2 (10–100μm) and to the period of incubation. Addition of EDTA (1mm) completely inhibited this destruction of cytochrome P-450 by CS2in vitro. Addition of CS2 to liver microsomal preparations resulted in moderate increases in the Ks values for type-I or type-II substrates, but these were insufficient to account for the inhibition of the mixed-function oxidases. We therefore suggest that desulphuration of CS2 leads to binding of the S to cytochrome P-450, denaturation of cytochrome P-450 to cytochrome P-420, and ultimately to destruction of these cytochromes by autoxidation.


Author(s):  
W. Kuenzig ◽  
M. Boublik ◽  
J.J. Kamm ◽  
J.J. Burns

Unlike a variety of other animal species, such as the rabbit, mouse or rat, the guinea pig has a relatively long gestation period and is a more fully developed animal at birth. Kuenzig et al. reported that drug metabolic activity which increases very slowly during fetal life, increases rapidly after birth. Hepatocytes of a 3-day old neonate metabolize drugs and reduce cytochrome P-450 at a rate comparable to that observed in the adult animal. Moreover the administration of drugs like phenobarbital to pregnant guinea pigs increases the microsomal mixed function oxidase activity already in the fetus.Drug metabolic activity is, generally, localized within the smooth endoplasmic reticulum (SER) of the hepatocyte.


1989 ◽  
Vol 121 (3) ◽  
pp. 219-223 ◽  
Author(s):  
Everett C. Burts ◽  
Hugo E. van de Baan ◽  
Brian A. Croft

AbstractAdult pear psylla, Psylla pyricola Foerster, from commercial pear orchards near Wenatchee, WA, were tested using a slide-dip technique for susceptibility to fenvalerate over a 5-year period from 1984 to 1988. Results were compared with those from similar tests using psyllids from an unexposed population near Corvallis, OR. During 5 years, resistance of adults to fenvalerate increased by 16- to 32-fold at Wenatchee while that of the Corvallis population did not change. In 1988, tests with five pyrethroids and pyrethroid – piperonyl butoxide combinations indicated that pear psylla adults also were resistant to permethrin and flucythrinate but not to fenpropathrin or cyfluthrin which contain a cyano group that reduces their susceptibility to oxidase metabolism. Piperonyl butoxide synergism was proportional to the level of resistance, indicating that resistance is probably due to increased mixed function oxidase activity. Implications of this study to control of post-diapause winter form adults in commercial pear orchards is discussed.


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