. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. URETHAN INHIBITION OF CLEAVAGE 393 in mitosis and cytokinesis (Anderson, 1956; Heilbrunn, 1956; Gross, 1957). It was thought that the application of multivalent cations might overcome the urethan inhibition, thus establishing the stage at which the gelation process is blocked by urethan. The organic cations were dissolved directly in a 1% solution of urethan in sea water. Isotonic solutions of the inorganic cations containing 1% urethan were mixed with 1 % urethan solutions in sea water to produce the desired concentrations.
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. URETHAN INHIBITION OF CLEAVAGE 393 in mitosis and cytokinesis (Anderson, 1956; Heilbrunn, 1956; Gross, 1957). It was thought that the application of multivalent cations might overcome the urethan inhibition, thus establishing the stage at which the gelation process is blocked by urethan. The organic cations were dissolved directly in a 1% solution of urethan in sea water. Isotonic solutions of the inorganic cations containing 1% urethan were mixed with 1 % urethan solutions in sea water to produce the desired concentrations. Early experiments (Schuel. 1958) indicated that small quantities of cations 100 -i 80- UJ > LU _l O 60 J 40 - 20 - 0 I control o o- 1% urethan _» " + arginine 10 % " + protamine 10~4%. 0 i 2 i 5 i 6 HOURS AFTER INSEMINATION FIGURE 2. Attempt to overcome urethan inhibition of division by means of arginine and protamine. Eggs were exposed to urethan-containing solutions 5 minutes after insemination. (inorganic calcium, histamine, protamine, arginine and lysine) could overcome the urethan inhibition. When fertilized eggs were kept in \% urethan, very few of the eggs began to divide until about three or four hours after division had taken place in the controls. The addition of these cations made it possible for more of the eggs to divide while still in urethan. Thus, at two hours after insemination, from 10% to 30% of such eggs had already divided. Not all of these promising results could be reproduced. In all subsequent ex- periments calcium, arginine and protamine failed to accelerate the recovery of eggs in urethan (Figs. 1 and 2). It was hoped that potassium might relieve the in- hibition by replacing the calcium bound in the cortex, and thus liberate it for action. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
