RT Journal Article SR Electronic T1 Antibiotics and Polyribosomes Chlortetracycline and Polyribosomes of Bacillus megaterium JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 401 OP 411 VO 3 IS 5 A1 CUNDLIFFE, ERIC YR 1967 UL http://molpharm.aspetjournals.org/content/3/5/401.abstract AB When added to suspensions of exponentially growing protoplasts, low concentrations of chlortetracycline (CTC) caused polyribosomes to break down to 70 S material. Increased concentrations of CTC gave less breakdown. With low drug concentrations the breakdown was complete within a few minutes and was followed by a process in which aggregation of ribosomes occurred. The aggregation process was sensitive to actinomycin D, and the product was degraded by RNase with the release of 70 S ribosomes. ACKNOWLEDGMENTS The author is indebted to the members of the Sub-Department of Chemical Microbiology for instructive criticism, to Dr. M. Schaechter for much stimulating discussion, and especially to Dr. K. McQuillen for his supervision of this work and his assistance during the preparation of the manuscript. This work was carried out during the tenure of a Medical Research Council Scholarship for Training in Research Methods.