Synthesis of Protein and Nucleic Acid by Disrupted Spheroplasts of Pseudomonas schuylkilliensis1

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RESUMO

Osmotically shocked spheroplasts obtained from Pseudomonas schuylkilliensis strain P contained about 54, 32, 28, and 82% of the total cellular protein, ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and phospholipid, respectively. This preparation was capable of incorporating 32P-orthophosphate into RNA and DNA, 3H-adenosine or 3H-uridine into RNA, and 3H-leucine or 14C-phenylalanine into protein. These activities were not found in the cytoplasmic fraction which contained most of the glucose-6-phosphate dehydrogenase activity. The synthesis of RNA by intact and disrupted spheroplast preparations was sensitive to actinomycin D, chromomycin A3, streptovaricin, rifampin, Lubrol W, Triton X-100, and sodium deoxycholate, whereas RNA synthesis by intact cells was insensitive to these agents. Ethylenediaminetetraacetic acid, porcine pancreatic lipase, the protoplast-bursting factor, high concentrations of salts, and washing the preparation inhibited the synthesis of RNA by disrupted spheroplasts but had little or no effect on intact spheroplasts. Most of the newly synthesized RNA made by disrupted spheroplasts had the characteristics of messenger RNA. The DNA present in this preparation functioned as a template for RNA synthesis; continued protein synthesis was dependent on concomitant RNA synthesis. An unusual feature of the preparation was the finding that the synthesis of macromolecules was completely dependent on oxidative phosphorylation.

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