F. J. Oppenoorth

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In all of six phosphate-resistant strains of Musca domestica L. a mutant gene is present which produces an altered ali-esterase. The modified enzymes are no longer irreversibly inhibited by the oxygen analogs of the insecticides to which the strains are resistant but can slowly convert them. In five of the strains the resistance is caused by this gene only.
The cause of parathion and propoxur resistance inTyphlodromus pyri was studied in a Dutch strain in which resistance was dependent on a semi-dominant gene. Activity of glutathione S-transferase and acetylcholinesterase and reaction rate of acetylcholinesterase with paraoxon and propoxur were measured in this resistant (R) and in a susceptible (S) strain.(More)
Three kinds of DDT-resistance with different genetic and physiological background are now known in the housefly: 1) DDT detoxication by DDT-dehydrochlorinase (DDT-ase) dependent on the geneD-ase on chromosome 5. This resistance can be overcome with DDT-F-DMC combinations. 2) an unknown detoxication mechanism dependent on chromosome 3 causing resistance that(More)
THE USE OF SYNERGISTS TO PREVENT DETOXIFICATION RAISES TWO PRINCIPAL PROBLEMS: (1) the importance of detoxification as a resistance mechanism and the extent to which synergists could contribute to a solution of the resistance problem, and (2) the role of detoxification as a cause of selectivity, and whether the loss in selectivity that might result from the(More)
negligible amounts could be recovered. Here, too, none was found in the excreta. One of us (F. J . O.) deals with this subject in the following communication. As to the nature of the metabolites of gamma-BHC we are entirely ignorant. I t should be emphasized tha t breakdown in the above sense and detoxication (conversion into a non-toxic compound) need not(More)