Two Types of Ribonucleoprotein in the Nucleolus of Intestinal Carcinoma of the Newt following Injection of Herring-Sperm Deoxyribonucleic Acid

Abstract

RECENTLY I demonstrated two types of ribonucleoprotein in the nucleolus of tumour cells in the squamous-cell carcinoma of the lizard Lacerta agilis¹. To establish whether a more general significance should be attached to this result I performed a corresponding investigation with the experimental carcinoma of the intestine of the newt Triturus alpestris following injection of herring-sperm deoxyribonucleic acid (eight days injection with 0.1 ml. of 5 per cent solution)². After killing the animals on the 40th day of the experiment the nucleolar differentiation of the tumour cells was studied by the toluidine blue-molybdate method^3,4. As in Lacerta¹, the ribonucleoprotein of the nuclear sap or parachromatin was coloured deep purple, the nucleolus partly assuming a green colour. Also in Triturus the existence of two types of ribonucleoprotein, if not actually demonstrated, had thus become highly probable. In the nucleoli a variable quantity of metachromatic ribonucleoprotein, as well as a number of very small vacuoles, appeared to be present, remaining unstained by the method described here. In the interphase cells the metachromatic ribonucleoprotein was most distinct, being in the form of small granules, hollow spheres or clusters of hollow spheres. Examination with a phase-contrast microscope showed that the nucleoli of the living tumour cells contained numerous very small vacuoles.