Studies on the Respiration of an Amoeba, Mayorella Palestinensis

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Abstract
The respiration of M. palestinensis in bacteria-free culture was investigated under various conditions, and the following results were obtained In nutrient solution containing 1 per cent peptone and 1 per cent glucose the respiration amounted to 117.3mmrO2/hour /107 amoebae, or 101.1 mm? O2/hour/10 mg. The respiration of cysts in the same solution amounted to 22 mm.3 1O2/hour/107 cysts. In salt solutions devoid of peptone and glucose the mean O2 consumption was 101.6 mm3 O2/h[degree]ur/107 amoebae. After the addition of 1 per cent peptone and 1 per cent glucose the mean increase of respiration was 15.2 per cent, while after the addition of peptone alone it amounted to 11.8 per cent. The addition of glucose alone had no influence on the O2 consumption. Amoebae starved for 24 hrs. consumed 102.1 mm3 O2 / hour/107 amoebae in the solution containing peptone and glucose, and 83.8 mm? O2/hour/107 amoebae in the peptone-free solution; thus the mean increase in the presence of peptone amounted to 22 per cent. No increase of respiration of starved amoebae in the presence of glucose could be noted. In peptone- and glucose-free solutions the respiration increased at pH 8.0 by 1.04 per cent compared with that at pH 6.0. In solutions containing peptone and glucose the respiration decreased by 4.5 per cent at pH 8.0 as compared with that at pH 6.0. Accordingly, the differnce between the respiration in peptone and glucose solutions and that in salt solutions alone was higher at pH 6.0 than at pH 8.0. The mean R.Q. was 0.864. Only slight differences in the R.Q. were found under the different exptl. conditions. It was demonstrated that considerable and varying amounts of CO2 are retained by the solutions used. Changes of O2 tension between 50 and 5 per cent had no influence on the respiration of M. palestinensis. Below a 5 per cent O2 content there was a decrease of the respiration, amounting to approximately 50 per cent of the normal respiration at 2-3 per cent O2 content, and it dropped to nearly 30 per cent of the normal at 1 per cent O2.
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