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C F Wilkinson

Publications and source records attributed to C F Wilkinson.

54 records · Page 3Linked to original sources
PubMed1973

Age-dependent arylsulphatase and sulphotransferase activities in the southern armyworm: a possible insect endocrine regulatory mechanism?

Arylsulphate and sulphotransferase activities were determined during the late larval development of the southern armyworm. Arylsulphatase titre attains a maximum during the moult and is at a minimum between moults. Sulphotransferase titre appeared to follow the inverse course. A possible enzymic regulatory mechanism for insect steroid hormones is discussed.

Animals↗
PubMed1972

Enzymic sulphation of p-nitrophenol and steroids by larval gut tissues of the southern armyworm (Prodenia evidania Cramer).

1. An enzyme system that catalyses the sulphation of p-nitrophenol, cholesterol, alpha-ecdysone, beta-sitosterol, dehydroepiandrosterone, oestrone and four other steroids of plant and insect origin was obtained from the soluble fraction of southern-armyworm gut tissues. 2. The enzyme system required ATP and inorganic sulphate, and activity was slightly enhanced in the presence of GSH. 3. The properties of this enzyme system with respect to pH, temperature, substrate and protein concentrations and various cofactors and reagents were studied. At -23 degrees C the enzyme preparation could be stored for 2 weeks without drastic loss of activity. At the end of storage for 1 month the loss of activity was approx. 21%. 4. The possible involvement of this enzyme system in insect endocrine control is discussed.

Adenosine Triphosphate↗
PubMed1971

Effects of synergists on the metabolism and toxicity of anticholinesterases.

Insecticide synergists enhance insecticidal action through their ability to block the enzymatic detoxification of insecticides with which they are combined. The structure of the synergist is therefore determined by the nature of the insecticide and the critical biochemical pathway responsible for its degradation.Synergists can be broadly classified as either analogue synergists, whose structure closely resembles that of the insecticide they synergize, or inhibitors of microsomal oxidation. Metabolism of the phenyl methylcarbamates is effected largely by the microsomal enzymes. Consequently microsomal enzyme inhibitors, such as the methylenedioxyphenyl compounds, the aryloxyalkylamines, the thiocyanates, the propynyl aryl ethers, and the 1,2,3-benzothiadiazoles, are all effective carbamate synergists. The detoxification pathways of the organophosphates, however, are more complex and include hydrolysis, dealkylation, and carboxylesterase pathways as well as oxidation. Because phosphorothioates are activated by oxidation, their toxicity is often antagonized by oxidase inhibitors. The effectiveness of different synergists towards resistant strains of insects is likely to vary in a manner that reflects the critical metabolic pathway on which resistance depends.

Amines↗
PubMed1970

An endogenous inhibitor of microsomal mixed-function oxidases in homogenates of the southern armyworm (Prodenia eridania).

1. A potent inhibitor of microsomal mixed-function oxidation has been isolated from the gut contents of larvae of the southern armyworm (Prodenia eridania). 2. Progressive inhibition is associated with a soluble proteinase with a molecular weight of approx. 26000. 3. Although the proteolytic activity of the inhibitor can be reduced by phenylmethanesulphonyl fluoride and other reagents, these materials are only partially effective in protecting the microsomal enzymes. 4. Inhibitory activity is decreased in the presence of bovine serum albumin.

Animals↗