The fate of RNA degradation products in starved cultures of Tetrahymena pyriformis W.

Abstract

SYNOPSISThe RNA content of a population of Tetrahymena pyriformis W was followed during the growth phases of the culture. The cellular RNA levels were found to reach a maximum in early log phase and to decrease throughout the remainder of the log and deceleration phases. There was a 25% decrease in RNA amount when cells in late stationary phase were compared to those in deceleration. This loss of RNA was mimicked when cells from the deceleration phase were suspended in a non‐nutrient buffered medium.Procedures were established to determine RNA content and the intra‐ and extracellular distribution of RNA degradation products, namely purine and pyrimidine bases and orthophosphate. Balance sheets are presented to show that the decrease in RNA levels was accompanied by an equivalent increase in purine and pyrimidine bases and phosphorus derivatives. The validity of the procedures employed was demonstrated. The influence of magnesium, cholesterol and glucose on the cells suspended in a non‐nutrient buffer was examined. Each was found to affect the ultimate distribution of RNA products in a characteristic fashion suggesting that each compound acts by a different mode of action.