. Biological structure and function; proceedings. Biochemistry; Cytology. CELL DIVISION AND PROTEIN SYNTHESIS 543 have found it to be around 60 min. before division in the logarithmic cell growing in proteose-peptone plus 0-4% liver extract. We have further analyzed this effect by exposing the cells (medium as before) to 16 mM/)-FPhe for only 20 min. After that time the inhibitor is removed by three washings with fresh growth medium, using the hand centrifuge. The control is similarly treated in a parallel tube. The results are shown in Fig. 5. In this case we have only delay, never block of d
. Biological structure and function; proceedings. Biochemistry; Cytology. CELL DIVISION AND PROTEIN SYNTHESIS 543 have found it to be around 60 min. before division in the logarithmic cell growing in proteose-peptone plus 0-4% liver extract. We have further analyzed this effect by exposing the cells (medium as before) to 16 mM/)-FPhe for only 20 min. After that time the inhibitor is removed by three washings with fresh growth medium, using the hand centrifuge. The control is similarly treated in a parallel tube. The results are shown in Fig. 5. In this case we have only delay, never block of division. The delays are plotted against the time of immersion into the inhibitor. Curve I represents the delay of division i (lengthening of time interval from EH to division i). Curve II measures the delay of division 2 in terms of extended intervals between divisions i and 2. Several experiments are combined but little attempt has been made of keeping them apart because. 60 120 Minutes after E H. 180 Fig. 5. Delay of synchronous division in proteose-ptptone by 16 niM p-FPhe for 20 min. The abscissa is the time when the exposure is initiated. Cnric I: Delay of division i. Curve II: Delay of division 2 (lengthening of time interval between divisions i and 2). both the svnchronizations and the responses to the analogue are so nicelv reproducible. Only the arrows which show the times for maximal division i and 2 separate between experiments. The results confirm those of Fig. 4 in showing that there is a critical time about 44 min. before division i, and 50 min. before division 2 when the response to/)-FPhe drops sharply. The new information conveyed by Fig. 5 is that the reaction to a standard treatment with the analogue increases (cur\e I) from EH to reach a maximum value (at t^^ min.) just before the drop in advance of division i. Further (curve II), that this cvclic variation repeats itself between divisions I and 2 and even extends back in time (left part of curve II) to befo
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