A microspectrophotometric analysis of staining with carmine, orcein and carmine-orcein.

Abstract

Microspectrophotometric measurements of carmine, orcein and carmine-orcein were made in solutions, in air-dried films and in stained adult and embryonic tissues of the domestic chicken. For individual stains only minor differences were found between dried dye and stained tissue. The absorption curve for carmine in solution showed a single peak at 490 mμ but was bimodal at about 530 and 570 mμ in dry films and stained tissue. Orcein showed a single broad peak at 510 mμ in solution; in dry films and stained tissue a broadening of the absorption curve in the red wavelengths was observed. The dye mixture carmine-orcein in solution showed a single peak at 500 mμ, but in tissue the spectral absorptions closely resembled carmine. With alum-like carmine, spectral changes due to the addition of iron were not detected. The results indicate that nuclear staining with carmine-orcein is due mainly to the carmine component of the mixture. Interpretation of spectral shifts indicates that acew-carmine is a metachromatic ...