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Biochemical Studies on Irradiated Protozoa. I. Effect of Metabolites on the Respiration of X-Irradiated Tetrahymena pyriformis *

Journal Article · · Journal of Protozoology
When Tetrahymena suspended in water were given increasing doses of radiation, oxygen consumption decreased with increasing dose, reaching 60 to 90% at 600,000 r. Cells irradiated in 0.07 M phosphate buffer, pH 7.4, showed no significant decrease in oxygen consumption even at 600,000 r. The decrease in respiration observed on irradiation of Tetrahymena pyriformis W in water with 300,000 r of x radiation was prevented by addition of pyruvate or acetate during or immediately after irradiation. Pyruvate stimulated the respiration of the xirradiated cells, particularly at 10 and 60 min postirradiation. Lactate markedly stimulated the respiration of control suspensions of Tetrahymena cells and oxidation of lactate by cells irradiated with 300,000 r was increased by 20 to 100%, depending on the concentration of lactate and the time after irradiation. Pyruvate was considerably more effective than lactate in increasing O/sub 2/ uptake of xirradiated cells, particularly at 10 min post-irradiation. Thioctic acid affected neither the respiration of control nor x-irradiated Tetrahymena nor the oxidation of pyruvate. The growth lag of Tetrahymena increased proportionately with increasing radiation dose; no cells survived 600,000 r. The presence of metabolites during irradiation did not affect the lag period or subsequent growth rates. The effects observed were discussed in terms of an alteration of the permeability of Tetrahymena after irradiation. (auth)
Research Organization:
Univ. of Connecticut, Storrs; and Marine Biological Lab., Woods Hole, Mass.
Sponsoring Organization:
USDOE
NSA Number:
NSA-16-021955
OSTI ID:
4838067
Journal Information:
Journal of Protozoology, Journal Name: Journal of Protozoology Journal Issue: 2 Vol. 9; ISSN 0022-3921
Country of Publication:
Country unknown/Code not available
Language:
English