The oxygen uptake ofTrypanosoma lewisiandTrypanosoma equiperdum, with especial reference to oxygen consumption in the presence of amino-acids

Standard conditions are described for preparing suspensions of washedTrypanosoma lewisiandT. equiperdumin modified Ringer–phosphate solution. 2. Oxygen consumption was measured with differential manometers, using microflasks containing 2–5 × 107trypanosomes in 0·9 ml. of reaction mixture. Measurements of oxygen uptake were carried out at 37° C. 3.T. lewisirespired slowly in the absence of substrate for up to 2 hr. The trypanosomes suffered little damage when stored at 5° C. for 24 hr. without substrate. No oxygen uptake was observed withT. equiperdumin the absence of substrate. The trypanosomes were viable after 24 hr. at 5° C. with glucose or glycerol as substrate, but not in the absence of substrate. 4. With glucose as substrate, the rate of oxygen consumption byT. lewisiincreased with the age of infection. This change was more marked with glutamine as substrate. 5. With glucosamine as substrate, the oxygen uptake ofT. lewisiwas at a slightly lower rate than with glucose. The rate of oxygen uptake was still lower with Nal-glutamic acid, asparagine, aspartic acid, casein hydrolysate, yeast extract and Difco Bacto-peptone. Thirteen other amino-acids had no effect on the motility of the trypanosomes. 6. With glycerol as substrate, the oxygen uptake ofT. equiperdumwas at a slightly lower rate than with glucose. The rate of oxygen uptake was very low with yeast extract, casein hydrolysate and Difco Bacto-peptone. No oxygen uptake or motility was recorded with glutamine, Nal-glutamic acid, glucosamine, asparagine, aspartic acid,dl-alanine, or Na acetate. Thirteen other amino-acids had no effect on the motility of the trypanosomes. 7. Ammonia was liberated from glutamine by adult and reproductive phaseT. lewisi.