The effects of adenosine triphosphate and dinitro- O-cresol upon the form and movement of Amoeba proteus: A pressure-temperature study

1. 1. When a relatively high concentration (0.002 M) of adenosine triphosphate was added to the normal culture medium (Brandwein solution) the amoebae slowly contracted, each into a dark rounded mass with numerous surface blebs and a large light central area. 2. 2. At a lower concentration (0.0005 M) the amoebae continued to display normal form and movement. However, the pseudopodia displayed an increased stability when subjected to the solating effects of high pressure. 3. 3. The stabilizing effects of ATP on the pseudopodia was measured at four temperatures (10 °, 15 °, 20 ° and 25 °C) and in each case the pressure differential amounted to approximately 500 lbs/in 2. 4. 4. Similar positive results were obtained when adenosine monophosphate was substituted for ATP, but in this case the concentration required was about four times higher. 5. 5. Essentially negative results were obtained using adenosine, inorganic phosphates (Na 2HPO 4 and Na 4P 2O 7) and dinitro- o-cresol. 6. 6. Dinitro- o-cresol, which alone gave little or no effect (except after several hours), produced a marked weakening of pseudopodial structure when used in combination with ATP. 7. 7. These results and those of previous experiments are discussed in relationship to the hypothesis that the plasmagel of the amoeba is a contractile system which can receive energy from the metabolism of high potential phosphate compounds in the cell.