Oxygen Consumption and Carbon Dioxide Elimination in Tetrahymena Geleii Furgason

Abstract

Unicellular organisms make excellent material for the study of various cellular phenomena. Tctrah\nncna t/clcii, a colorless holotrichous ciliate, is an exceptionally desirable organism for such physiological studies, mainly because it is readily grown in rather simple, sterile organic media. This organism contains cytochromes c, b, a, and possibly a._, and its oxygen consumption is inhibited by cyanide and carbon monoxide (Baker and Baumberger, 1941). It grows well at ordinary oxygen tensions, but is most prolific in pure "oxygen (Pace and Ireland, 1945). It soon dies in oxygen tensions below 10 mm. Hg partial pressure.Many investigations have been carried out with Tetrahymena as the experimental organism. There is, however, much to be desired in respect to our knowledge concerning respiratory metabolism ; knowledge that may lead to a better understanding of the respiratory mechanisms of cells in general. Since very little is known concerning oxygen consumption, carbon dioxide elimination, and respiratory quotient in Tetrahymena, the following investigations were made.

Density-Dependent Individual and Population-Level Metabolic Rates in a Suite of Single-Celled Eukaryotes

“…Our results are the first to illustrate a broad, general picture of the relationship between density and metabolic rate in protists. The literature is replete with studies on the metabolic rates of protists, and some have observed that the density of cells in a sample negatively affects the rate [13][14][15][16][17]. McCashland and Kronschnabel [17] suggested that competition for nutrients was the cause, foreshadowing our results here.…”

Metabolic Efficiency of Tetrahymena pyriformis, Strain W, as Related to Culture Age

“…The metabolic rates recorded are due primarily to the metabolism of endogenous energy substrates which are not completely depleted even by three hours of starvation (lower pair of curves in Fig. The real value of these data to the experiments reported here lies in the fact that the resistance of the cells to the entry of succinate verifies the cellular vitality, for it has been shown (Seaman, 1953) that homogenates or cell-free extracts of T. pyriformis It has been stated frequently that the metabolic potential of T. pyriformis in culture decreases as the culture ages (Peters, 1929;Ormsbee, 1942;Pace and Lyman, 1947). The real value of these data to the experiments reported here lies in the fact that the resistance of the cells to the entry of succinate verifies the cellular vitality, for it has been shown (Seaman, 1953) that homogenates or cell-free extracts of T. pyriformis It has been stated frequently that the metabolic potential of T. pyriformis in culture decreases as the culture ages (Peters, 1929;Ormsbee, 1942;Pace and Lyman, 1947).…”

Studies on the nongrowth metabolism of the different strains of Tetrahymena cells by isothermal microcalorimetry

“…In the absence of nutrients, the limiting factor for the cell metabolism was oxygen or room. Pace and Lyman [13] had reported that the average oxygen consumption of the hungry Tetrahymena geleii cells in the different growth periods was all \400 lL h -1 per million cells. In the present study, the peak time for the maximum power output of Tetrahymena cells was \15 h. Making reference to 400 lL h -1 oxygen consumption per million cells, Tetrahymena cells oxygen consumption within 15 h was \2.25 mL, which was lower than the oxygen volume (about 3 mL) in the experimental ampoule bottles.…”