Complete Inhibition Of Protein Synthesis Research Articles

Protein synthesis requirements for the first two cleavages in sea urchin eggs

Complete inhibition of protein synthesis with puromycin does not always result in the arrest of the first cleavage. The percentage of cells that divide increases as puromycin treatment is delayed. In any batch of fertilized eggs (even from the same female) some eggs complete their required protein before others. The different time required to complete the synthesis of proteins necessary for the first cleavage may indicate that the amount of these proteins varies in the eggs even before fertilization. The second cleavage, however, is completely dependent on the protein synthesis that takes place after fertilization.

溶原菌に於けるファージ増殖に関する研究

The effect of chloramphenicol on the phage development of UV induced E. coli, K12 (λ) was investigated by the one step growth experiment and the quantitative analyses of protein and of DNA synthesis.When chloramphenicol is added to the induced culture at any time between 40 and 60 minutes after induction (the minimum latent period of λ is 60 minutes), induced cells lyse prematurely and the mature phage particles are liberated. Introduction of chloramphenicol during the first 35 minutes, however, is followed by a consequence that the number of infective centers tested gives less than the number of treated bacteria. These results are in fair agreement with Delbrück's finding which has been ascertained by the technique of stopping phage growth and making the cells to lyse prematurely by exposure to the KCN. It is confirmed that chloramphenicol treatment inhibits the induced bacteria from further phage development-similarly to the experiments with strain B infected with T1, and that the mature phage particles begin to appear in induced bacteria at about 40 minutes after induction.At the earlier stages of the phage development, the chioramphenicol inhibition is reversibly removed and its influence does not seem to be reserved when the drug is diluted out. Namely, the length of the latent period is prolonged as much time as one of the exposure to the chloramphenicol, and essential latent period is not affected by the additions up to 45 minutes after induction; there is no prolongation of latent period and bacteria burst at normal latent period, if induced bacteria are still later exposed to chloramphenicol. The average phage yield too is not influenced by the presence of chloramphenicol for a short period either at initial or terminal stage. However, a, marked decrease in burst size is noted with the interruption of phage development at the middle portion, i.e. in this case there seems to be a somewhat irreversible effect of chioramphenicol on the mechanism of phage develpment.In a growing culture of K12, chloramphenicol at bacteriostatic concentrations depresses the both ribonucleic and desoxyribonucleic acid syntheses considerablly, but a lesser extent in comparison with the complete inhibition of protein synthesis. An identical suppression is also found in the DNA synthesis of induced bacteria, when chloramphenicol is added as late as 30 minutes after induction. In contrast, the chloramphenicol addition immediately after induction shows the complete inhibitory effect on the phage DNA synthesis, as on the protein synthesise Further more, the synthesis of phage DNA begins lately as equal to the affecting time of chioramphenicol when the bacteria are exposed to the drug for a given period after induction.These results indicate that the DNA synthesis of the induced K12 requires the new metabolic system (s) which does not participate in the host DNA synthesis, and that some enzyme proteins constructing such system (s) are synthesized immediately after induction and are continued to be formed during the first half of the latent period. It seems more adequate in the “photorestorable phase” to be interpreted not merely as the conversion of the prophage into the vegetative state takes place, but also as the metabolic reactions for phage development are already initiated.

溶原菌におけるプアージ増殖に関する研究

The effect of chloramphenicol on the phage development of UV induced E. coli, K12 (λ) was investigated by the one step growth experiment and the quantitative analyses of protein and of DNA synthesis.When chloramphenicol is added to the induced culture at any time between 40 and 60 minutes after induction (the minimum latent period of λ is 60 minutes), induced cells lyse prematurely and the mature phage particles are liberated. Introduction of chloramphenicol during the first 35 minutes, however, is followed by a consequence that the number of infective centers tested gives less than the number of treated bacteria. These results are in fair agreement with Delbruck's finding which has been ascertained by the technique of stopping phage growth and making the cells to lyse prematurely by exposure to the KCN. It is confirmed that chloramphenicol treatment inhibits the induced bacteria from further phage development-similarly to the experiments with strain B infected with T1, and that the mature phage particles begin to appear in induced bacteria at about 40 minutes after induction.At the earlier stages of the phage development, the chioramphenicol inhibition is reversibly removed and its influence does not seem to be reserved when the drug is diluted out. Namely, the length of the latent period is prolonged as much time as one of the exposure to the chloramphenicol, and essential latent period is not affected by the additions up to 45 minutes after induction; there is no prolongation of latent period and bacteria burst at normal latent period, if induced bacteria are still later exposed to chloramphenicol. The average phage yield too is not influenced by the presence of chloramphenicol for a short period either at initial or terminal stage. However, a, marked decrease in burst size is noted with the interruption of phage development at the middle portion, i.e. in this case there seems to be a somewhat irreversible effect of chioramphenicol on the mechanism of phage develpment.In a growing culture of K12, chloramphenicol at bacteriostatic concentrations depresses the both ribonucleic and desoxyribonucleic acid syntheses considerablly, but a lesser extent in comparison with the complete inhibition of protein synthesis. An identical suppression is also found in the DNA synthesis of induced bacteria, when chloramphenicol is added as late as 30 minutes after induction. In contrast, the chloramphenicol addition immediately after induction shows the complete inhibitory effect on the phage DNA synthesis, as on the protein synthesise Further more, the synthesis of phage DNA begins lately as equal to the affecting time of chioramphenicol when the bacteria are exposed to the drug for a given period after induction.These results indicate that the DNA synthesis of the induced K12 requires the new metabolic system (s) which does not participate in the host DNA synthesis, and that some enzyme proteins constructing such system (s) are synthesized immediately after induction and are continued to be formed during the first half of the latent period. It seems more adequate in the “photorestorable phase” to be interpreted not merely as the conversion of the prophage into the vegetative state takes place, but also as the metabolic reactions for phage development are already initiated.