RESPIRATORY STUDIES OF SINGLE CELLS. III. OXYGEN CONSUMPTION DURING CELL DIVISION

Abstract

In the present investigation we analyzed oxygen consumption during the 1st 2-5 cell divisions in single eggs from 3 echinoderms (Strongylocentrotus purpuratus, S. franciscanus, Dendraster excentricus). and from the echiuroid worm Urechis caupo employing the reference diver technique (Scholander, Claff and Sveinsson, 1952a). There is poor correlation between cell volume and oxygen consumption in individual eggs, both of which vary considerably. Oxygen consumption during cell division may proceed without measurable change in rate (usual in Urechis, S. franciscanus) or it may show cycling correlated with the cell divisions (Dendraster and S. purpuratus). If cycling occurs, cytoplasmic cleavage is associated with an abrupt rise in oxygen consumption. The cycling, if present, is strongly damped and often disappears after 2-3 divisions. When started, cleavage can proceed without oxygen consumption (S. franciscanus). Our runs on single eggs reflect in some respects the results gained by mass runs, but we are able to supply a more exact picture with respect to timing, curve shape, and variations in individual cells.