Toxicity of aromatic acids to the larvae of the mosquito Aedes aegypti L. and the counteracting influence of amino acids

Abstract

The toxicity of benzoic acid to these larvae was reduced in the presence of glycine. The efficiency of this counteraction decreased as the larvae matured and was greatest at pH 7 or below. The quantitative relationship of the decrease in benzoic acid toxicity in the presence of low glycine concentrations suggested an equimolar detoxication reaction. Benzoic acid was 15 times as toxic as hippuric acid to these larvae. Using [[alpha]-14C] glycine it was shown that mosquito larvae can synthesize hippuric acid and probably excrete the conjugated product. Thirty amino acids and closely related compounds were tested for their efficiency in reducing the toxicity of benzoic acid. Although glycine was the most efficient amino acid, in its absence many others were capable of reducing the toxicity of benzoic acid. The structural specificity for this counteraction is discussed. The toxicity of 50 aromatic acids or closely related compounds was determined. The relation of structure to the toxicity and mechanism of action of these acids is discussed. An example is presented for a synergistic action through competition for a common detoxica-tion mechanism.