Antimetabolites in the nutrition of Aedes aegypti L. larvae : The substitution of choline by related substances and the effect of choline inhibitors

Abstract

The quantitative requirement for choline chloride of Aedes aegypti larvae grown on a chemically defined diet has been studied. Carnitine and the specific carnitine inhibitor, γ-butyrobetaine, had no effect when added to the basic diet containing an adequate amount of choline. Carnitine, betaine, γ-butyrobetaine, and γ-aminobutyric acid could not replace choline in the diet, and had no choline-sparing activity. 2,2-Dimethylaminoethanol had a weak choline effect, which could not be increased by the addition of l-methionine. The anticholine activity of inositol, triethylcholine, and 2-amino-2-methyl-1-propanol, which have been repored to be choline antagonists in different systems, has been tested. Inositol was found to be without any choline-like or anticholine effect. Triethylcholine was toxic, but no choline antagonism could be demonstrated. The toxic effect of 2-amino-2-methyl-1-propanol could be overcome by the addition of choline within a certain range, whereas the toxicity of higher amounts of the inhibitor was irreversible. The inhibition index was lower in the presence of higher amounts of the metabolite in the medium. The specificity of the choline requirement and the effect of choline-inhibitors on mosquito larvae are compared to those of other organisms.