THE EFFECT OF FOOD CONTENT AND TEMPERATURE ON RESPIRATION IN PELOMYXA CAROLINENSIS WILSON

¹ Department of Physiology and Pharmacology, College of Pharmacy, University of Nebraska, Lincoln; Department of Biology, Saint Francis Seminary, Milwaukee

1. The rate of respiration in Peolmyxa carolinensis at 25° C. is closely correlated with the amount of food material present in the cytoplasm.

2. The rate of oxygen consumption at 25° C. was found to be 0.244 ± 0.028 mm.³ per hour per mm.³ cell substance and does not differ greatly from that of Amoeba proteus and Actinosphaerium eichhornii. The rates were less at low temperatures (15° C.) and greater at high temperatures (35° C.).

3. Temperatures above 35° C. are usually lethal to Pelomyxa, although in several tests the oxygen consumption at 40° C. for one hour was obtained.

4. The respiratory quotient is much lower for starved specimens (R.Q.: 0.56) than for well-fed specimens (R.Q.: 0.87) and is approximately equal to that of other free-living Protozoa.

5. As the temperature is increased, the rate of oxygen consumption increases, but the rate of increase becomes progressively greater.

6. The temperature coefficient for the rate of respiration in Pelomyxa carolinensis is nearly the same as that in Paramecium, varying from 1.7 between 15° and 25° C. to 2.1 between 25° and 35° C.