Free amino acids and related compounds during metamorphosis of the blowfly Phormia regina

Abstract

Phormia regina larvae raised on an aseptic semi-defined diet have been employed to determine the profiles of free amino acids and related ninhydrin-positive compounds during metamorphosis. Two-dimensional high-voltage ionophoresis, paper chromatography, enzymatic reactions, hydrolysis, and specific colour tests were used to identify all the major peaks obtained by running deproteinized extracts on an automatic amino acid analyser. Each developmental stage was examined before and after acid hydrolysis of the extracts, and profiles of the following substances recorded: cysteic + homocysteic acids, phosphoserine + phosphothreonine, glycerophosphoethanolamine, phosphoethanolamine, taurine, urea, l-methionine- d-sulphoxide, aspartic acid, glutamine, threonine, serine, glutamic acid, proline, glycine, alanine, α-amino- n-butyric acid, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, β-alanine, β-aminoisobutyric acid, γ-amino- n-butyric acid, ethanolamine, ammonia, lysine, histidine, and arginine. At certain stages of development ornithine, tryptophan, and a number of peptide peaks were observed but these have not been estimated. No evidence was obtained for the presence of any d-amino acids. Following acid hydrolysis aspartic acid, glutamic acid, and glycine increased the most, β-alanine, β-aminoisobutyric acid, γ-aminobutyric acid, taurine, and tyrosine showed no increase in titre, while the remaining components increased to an intermediate extent. During adult development the concentration of the following amino acids showed the most marked changes: tyrosine, methionine sulphoxide and methionine, proline and glutamic acid, but the titres of most of the compounds examined varied to some degree.