Studies on the protein metabolism of Culex pipiens L.—II : Quantitative differences in free amino acids between male and female adult mosquitoes

Abstract

The free ninhydrin-positive substances in the adults of Culex pipiens (autogenous form) have been studied by partition chromatography. The methanol extract from individuals shortly after emergence contains α-alanine, β-alanine, arginine, aspartic acid, cystine, glutamic acid, glutamine, glycine, histidine, leucine (and/or iso-leucine), lysine, methionine sulphoxide, proline, serine, threonine, tyrosine, valine, and 2 peptides. Adults maintained for 4–6 days on a sucrose diet become poor in free amino acids. This is especially true for valine, leucine, threonine, tyrosine, and lysine, all of which have been shown to be essential for higher organisms. Male and female adult mosquitoes 4–6 days old differ distinctly in their chromatographic patterns. There is an accumulation of free β-alanine in males and methionine sulphoxide in females. Evidence has been brought forward to show that this difference is not directly due to materials accumulated in the gonads or other sexual organs. The metabolic significance of these amino acids in connexion with the reproductive processes is discussed.