Uptake of Phenylalanine by Tetrahymena pyriformis

Abstract

THE nutritional requirements of Tetrahymena pyriformis are well known, and it can be cultured in a chemically defined medium. Nevertheless, some aspects of its feeding are still not clear. In nature the organisms are believed to feed phagotrophically on bacteria¹. In synthetic media, however, food vacuoles are rarely seen. Although Seaman² found that vacuole formation could be stimulated by the addition of proteose peptone-yeast extract to the medium, the phagotrophic activity induced was not sufficient to supply the energy requirements of the organisms.