The hydrogen-ion concentration and oxidation-reduction potential of the cell-interior before and after fertilisation and cleavage: A micro-injection study on marine eggs

Abstract

In the 1st of these papers pH and rH indicators were micro-injected into the cell-interior of Amoeba proteus. The approximate pH of the protoplasm was calculated to be 7.6 and the internal rH between 17 and 19. A discussion of the necessary assumptions in these calculations was given. In this, the 2nd, paper a report is made of micro-injections of the indicators into 3300 marine eggs, including those of 4 echinoderms, a tunicate, and a polychaete worm. The internal pH of all the eggs studied was near 6.6. It did not change on fertilization, and showed no rhythmical changes afterwards. It was constant as far as the 16-cell stage, and remained unaffected by severe morphological changes produced by asphyxia, until the stage of spontaneous cytolysis was reached. Cytolysis, in whatever way produced, lowered the pH to a value between 4.0 and 5.0. The rH of the egg-cells varied more than the pH but not outside the limits 19-22; it did not change on fetilization nor afterwards. and altered little, if at all, on cytolysis. It was noted that the method of vital staining and the method of micro-injection gave diametrically opposite results, and it was concluded that by the time the membrane became permeable to the dyes the cell was already far from normal.