. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. uo HANS BOREI for filling the diver, plus a minimum of time for attaining temperature equilibrium and then for obtaining two measurements suitably apart, cannot be pressed down to much under 40 minutes. The earlier values may, however, be found by extra- polation, but the most interesting period, viz. the shedding, will only be described rather approximately by this method. A gradual decrease in the oxygen consumption of the shed unfertilized egg has already been reported for the Ciona egg by Holter and Zeuthen (1944) using
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. uo HANS BOREI for filling the diver, plus a minimum of time for attaining temperature equilibrium and then for obtaining two measurements suitably apart, cannot be pressed down to much under 40 minutes. The earlier values may, however, be found by extra- polation, but the most interesting period, viz. the shedding, will only be described rather approximately by this method. A gradual decrease in the oxygen consumption of the shed unfertilized egg has already been reported for the Ciona egg by Holter and Zeuthen (1944) using Cartesian diver technique. Lindahl and Holter (1941) in their diver experiments on Par. have not stated the time after removal from the ovary, but point out that it would probably have been of importance. In fact, the results presented in Figure 2 show how necessary such a precaution is if comparable values are I2O 24O 36O MINUTES AFTER REMOVAL FROM OVARY FIGURE 2. Relative rate of oxygen consumption of ripe Psammechinus miliaris eggs in relation to time after removal from ovary. Results from 4 diver experiments. Values at 230 minutes (cf. ) put = 100. Final asymptote (A) indicated. Arrow stands for chosen point of comparison for absolute rate measurements. Evaluated time span (S) in such experiments indicated. The curve in Figure 2 closely resembles that of the endogeneous respiration of baker's yeast (Borei, 1942) where one is also concerned with cells cut off from external supply of metabolic material; the gradually decreasing respiration is com- posed of two parts. One proceeds monomolecularly and is thought to be governed by the rapidly decreasing amount of an initially present substrate. The other con- tinues with a constant rate for a considerable time; its rate is thought to be limited by the available amount of an enzyme. Mathematical analysis of the curve in Figure 2 shows that even the respiration of the unfertilized egg can be described in this way
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
