Some Aspects of Phagotrophy in Tetrahymena*

Abstract

Ingestion of fluid by axenically cultured Tetra‐hymena pyriformis requires an inducer, which can be provided by peptone‐yeast extract broth. Cells in this medium contain many phagotrophic vacuoles; the formation of these is readily followed by allowing peptone‐yeast grown cells to ingest the impermeable dye, trypan blue. Tetrahymena grown in synthetic medium contain only few vacuoles and do not ingest trypan blue to any significant degree. Addition of peptone‐yeast medium to cells grown in a synthetic medium “induces” vacuolar formation and uptake of the dye. Calculations based on the rate of ingestion of trypan blue and of heat killed cells of Serratia marcescens indicate that the phagotrophic process cannot adequately supply the nutritional demands of the organism. Experiments using the colored amino acid analog, 3,5‐dinitrotyrosine contrast the rapid penetration of material through the cell membrane with the more sluggish route of phagotrophy.

Nutrient uptake in Tetrahymena pyriformis

“…Few investigators have compared the contribution of the food vacuoles to total nutrient uptake of T. pyriformis (LWOFF (55), SEAMAN (98,99), PRUETT, CONNER & PRUETT (77), NILSSON (63), RASMUSSEN (79,80), RASMUSSEN • OR1AS (84,85) and ORIAS & RASMUSSEN (71,72)). There are, therefore, no reasonably detailed descriptions of nutrient uptake for this cell.…”

PINOCYTOSIS IN ACANTHAMOEBA CASTELLANII

“…The culture medium contains 1.5~o proteose-peptone and 1 5~vv 0 glucose as major components. The effect of proteins and amino acids on stimulating pinocytosis in the large amebas has been well documented (5), and there is evidence in another protozoan, Tetrahymena, that proteose-peptone solution stimulates vacuole formation and fluid uptake (24) In order to rule out that the proteosepeptone solution might be inducing pinocytosis in Acanthamoeba, inulin uptake was measured B~Am BOWERS A~D Tno~IAs E. OLSZEWSKI P, nocygosi~ in Acanthamoeba castellan~i lqkGURE 1 Uptake of albumin as a function of incubation time and temperature. Cells were incubated as described under Methods with human se~arm albumin-t51I (1.9 X 105 cpm/ml).…”

THE INFLUENCE OF THE MODE OF NUTRITION ON THE DIGESTIVE SYSTEM OF OCHROMONAS MALHAMENSIS

“…Phagocytosis Protozoan phagocytosis and metazoan phagocytosis are remarkably similar. Mouse mononuclear phagocytes growing in tissue culture (8,9,10) and protozoa growing in nutritionally complete osmotrophic media (38,39) form few cytoplasmic vacuoles, and acid hydrolases are localized in vesicles . Upon phagocytic stimulation, however, cytoplasmic vacuoles increase in number and acquire lysosomal enzyme activity as demonstrated by Gomori stain (8, 9, 10, 15, 29, 38, 39) .…”

“…The occurrence of acid phosphatase in digestive vacuoles has been demonstrated in many different types of protozoa (31) . Tetrahymena pyriformis forms few food vacuoles when cultured in an axenic, chemically-defined medium (38,39), whereas phagocytosis increases vacuolization (15) .…”

“…VOLUME 43,1969 Food vacuoles in protozoa are formed by membrane invagination which engulfs food particles and a small amount of surrounding medium (31,38,39) . It is not known whether food vacuoles in 0 .…”