Studies on the Development of Eye-Antennal Discs of <i>Drosophila melanogaster</i> in Tissue Culture

Abstract

1. In order to ascertain how the cephalic complexes or the facet-increasing substances act on the development of the eye, the eye-antennal discs and the cephalic complexes taken out from the mature third-instar larvae (95 hours old after hatching at 25°C) of several eye-mutant strains of D. melanogaster were cultured in vitro in synthetic media with or without the facet-increasing substances.2. The amount of the metamorphic hormone secreted from five cephalic complexes in a hanging-drop seems to be sufficient for the growth and differentiation of the eye-antennal discs. The cephalic complexes of several eye-mutant larvae seem to provide some unknown factors promoting the growth and differentiation which are characteristic to srveral eye-mutant strains.3. Ammonium lactate and acetamide showed the significant effects upon the growth and differentiation of the eye-antennal discs in some mutant strains with the genetical back grounds of the wild type, cultured together with their own cephalic complexes, and upon those of the eye-antennal discs of Oregon-R cultured together with the cephalic complexes of these mutant strains.4. Urea showed most marked effects upon the eye-antennal discs of several strains except Dp to promote the growth and differentiation of the wold type. Polypeptone also had effects similar to urea on all strains except Dp.5. The eye- antennal discs of the Dp strain seems to be different from other eye-mutant strains in the responsibility to the cephalic complexes of the wild type, although the cephalic complexes of this strain seems to be similar to other eye-mutant strains in promoting the growth and differentiation of the eye-antennal discs of the wild type in media containing acetamide.