Nutrition of Tetrahymena geleii (Protozoa, Ciliata)

Abstract

All attempts to grow Tetrahymena geleii in a medium of known composition have, so far, failed. Failure to obtain growth in anything but peptones led Lwoff1 to formulate the hypothesis that the ciliate requires polypeptides and cannot utilize free amino acids. Earlier2 he had hinted that the failure of growth in a mixture of silk peptone, fibrin peptone and gelatin, which contains all the known amino acids, is the result of the lack of some supplementary substance. Gelatin3 will support growth if supplemented with a small amount of yeast extract; indeed, it is stated4 that transplantable growth is obtained in gelatin plus thiamin and riboflavin. Silk peptone gives slight, but transplantable, growth if thiamin is added.5It is clear, then, that the question of the amino acid requirement of T. geleii cannot be answered until more is known of the supplementary needs.In order to discover the vitamin (or supplement) requirements, a basal medium is necessary. Since it had been found that the ciliate will grow wel...