Metabolism of nucleic acids and proteins of normal and chemosterilized house flies during oögenesis and embryogenesis.

Abstract

Adult Musca domestica L. were chemosterilized by oral administration of 5 μg/fly of p,p• -bis (1-aziridinyl) -N- (3-methoxypropyl) phosphinothioic acid after emergence. Nucleic acid and protein syntheses during oogenesis and embryogenesis were compared with that of normal flies. Unfertilized eggs of normal flies were also subjected to analysis. In the ovaries during oogenesis protein synthesis in both normal and chemosterilized females was similar quantitatively, with a 6-fold increase during maturation of the ovaries and 1st egg cycle. After egg deposition of the 1st chamber was completed, there was a cyclic decrease and increase in protein during the development of the 2nd chamber. There was less deoxyribonucleic acid (DNA), especially low-molecular-weight DNA intermediates, in the ovaries from chemosterilized females. Although the amount of ribonucleic acid (RNA) and RNA intermediates in the ovaries from the treated flies appeared to be normal, the purine/pyramidine ratio of the RNA nucleotides of the treated ovaries was consistently higher than that from normal ovaries. In the nonviable eggs from chemosterilized flies, protein synthesis proceeded at a normal rate even though there was no measurable synthesis of DNA. RNA synthesis continued but at a lower rate than that in normal fertile eggs. The purine/pyramidine ratio of the egg RNA nucleotides from normal and chemosterilized eggs was similar in the newly oviposited eggs, but the ratio was considerably higher in the RNA from chemosterilized eggs after 6 hr of incubation at 37°C. In unfertilized nonviable eggs horn normal flies, protein synthesis and a small quantity of DNA synthesis occurred after oviposition.