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

¹ Dept. of Biological Chemistry and Laboratory for Surgical Research, Harvard University Medical School, Boston, Mass.; Oceanographic Laboratories, University of Washington, Friday Harbor, Washington; Hopkins Marine Station, Stanford University, Pacific Grove, California

1. In the present investigation we have analyzed the oxygen consumption during the first two to five cell divisions in single eggs from three echinoderms (Strongylocentrotus purpuratus, S. franciscanus, Dendraster excentricus) and from the echiuroid worm Urechis caupo, employing the reference diver technique (Scholander, Claff and Sveinsson, 1952a).

2. There is poor correlation between the cell volume and the oxygen consumption in individual eggs, both of which vary considerably.

3. The 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, the cytoplasmic cleavage is associated with an abrupt rise in the oxygen consumption.

4. The cycling, if present, is strongly damped and often disappears after two to three divisions.

5. When started, cleavage can proceed without oxygen consumption (S. franciscanus).

6. 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.

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