Puromycin: Effect on Messenger RNA Synthesis and β-Galactosidase Formation in Escherichia coli 15T-
16 Apr 1965-Science (American Association for the Advancement of Science)-Vol. 148, Iss: 3668, pp 371-373
TL;DR: Incubation of Escherichia coli 15T- in the presence of puromycin inhibits the inducible formation of β-galactosidase to a greater extent than it inhibits protein synthesis.
Abstract: Incubation of Escherichia coli 15T(-) in the presence of puromycin inhibits the inducible formation of beta-galactosidase to a greater extent than it inhibits protein synthesis. In E. coli 33.00 beta-galactosidase formation is also more sensitive to the presence of puromycin than is protein synthesis. In the presence of glycerol (but not in its absence) puromycin prevents the production of messenger RNA for beta-galactosidase, presumably as a result of catabolite repression.
Citations
More filters
TL;DR: This chapter focuses on three devices: catabolite repression, transient repression, and catabolites inhibition, which regulate the utilization of many carbohydrates, which influences many aspects of microbial growth and metabolism.
Abstract: Publisher Summary This chapter focuses on three devices: catabolite repression, transient repression, and catabolite inhibition, which regulate the utilization of many carbohydrates. Catabolite repression is a reduction in the rate of synthesis of certain enzymes, particularly those of degradative metabolism, in the presence of glucose or other readily metabolized carbon sources. Catabolite inhibition is a control exerted by glucose on enzyme activity rather than on enzyme formation, analogous to feedback inhibition in biosynthetic pathways. Catabolite repression influences many aspects of microbial growth and metabolism. In addition to the well known repressions of carbohydrate utilization and amino-acid degradation in bacteria and yeast, catabolite repression affects the formation of enzymes that function in the tricarboxylic acid cycle, glyoxylate cycle, fatty acid degradation, carbon dioxide fixation, and the respiratory chain. In higher organisms, catabolite repression has been observed in sugar cane, rats, and man. The question of whether catabolite repression acts to inhibit the transcription of DNA into m-RNA or to inhibit translation of messenger into protein has received conflicting answers. Catabolite repression is a control system that usually affects catabolic enzymes. If catabolite repression and transient repression are not mediated by the specific apo-repressor of each operon, there must be another protein that recognizes the low molecular-weight effector. The significance of a control mechanism, which influences the activity as opposed to the concentration of a carbohydrate-metabolizing enzyme is readily appreciated because bacteria have a limited ability to change enzyme concentrations.
163 citations
TL;DR: The results indicate that the decreased insulin-stimulated glucose transport capacity, in the insulin-deficient diabetic muscle, is not a direct consequence of the lack of insulin or of high glucose concentrations, and suggest the presence of some labile factor that might inhibit the glucose transport system.
132 citations
TL;DR: It appears that an inactivating system is formed during the induction cycle which is responsible for the removal of the induced enzyme, and the turnover of the enzyme under basal conditions may be much slower than the rate of inactivation of theinduced enzyme.
88 citations
TL;DR: The data suggest that nisin synthesis occurs by a mechanism similar to that of protein synthesis, and was more sensitive than protein synthesis.
Abstract: SUMMARY: A reaction mixture is described consisting of a buffered solution of amino acids, salts, growth factors and glucose in which freshly harvested washed Streptococcus lactis incorporated radioactive tracers and synthesized nisin. Rapid nisin synthesis started after a delay of 30-60 min. but bacteria pre-incubated in the reaction mixture synthesized nisin without delay although the rate of protein synthesis remained the same as that of freshly harvested bacteria. Although growing S. lactis is sensitive to penicillin and mitomycin these antibiotics had no effect on nisin synthesis by washed organisms. Actinomycin D inhibited uptake of tritiated uridine immediately and inhibited nisin synthesis after a delay of about 60 min. Antibiotics which interfere with protein synthesis, e.g. chloramphenicol, puromycin and terramycin also interfered with nisin synthesis. The inhibition was immediate and occurred irrespective of whether the antibiotics were added at the beginning of an experiment or after 50 min. Nisin synthesis was more sensitive than protein synthesis. The data suggest that nisin synthesis occurs by a mechanism similar to that of protein synthesis.
72 citations
TL;DR: The results indicate that protein synthesis is involved in the later as well as the earlier stages of development; what specially characterizes the later stages, prior to the "transition point," is a dramatic response to partial inhibition of protein synthesis.
Abstract: The effects of puromycin on synchronized Tetrahymena pyriformis were investigated at two different concentrations, 43 µg per ml and 430 µg per ml. The rate of incorporation of histidine-14C into hot TCA-insoluble material was reduced by 30% at the low concentration and by 80–90% at the high concentration. The rate of oxygen uptake was lowered by only 10–20% at both concentrations. Cell division was prevented at both concentrations, if the drug was added prior to a "transition point" at about 45 min after the end of the synchronizing treatment. Development of "anarchic field" oral primordia was arrested, while primordia in early stages of membranelle differentiation were resorbed. Resorption began shortly after addition of the drug, and proceeded most rapidly at the lower concentration. If the drug was added after the "transition point," cell division and oral primordium formation were completed with only slight delay at the low concentration, and with considerable delay (in some cases complete arrest) at the high concentration. The results thus indicate that protein synthesis is involved in the later as well as the earlier stages of development; what specially characterizes the earlier stages, prior to the "transition point," is a dramatic response to partial inhibition of protein synthesis. It is suggested that this response involves the activation or release of a latent intracellular degradative system which is specific for developing structures.
41 citations
References
More filters
TL;DR: During the induction phase a messenger RNA specific for β-galactosidase is produced which directs the subsequent synthesis of the enzyme in the inducer-free medium, which largely prevents the subsequent production of normal enzyme and causes the formation of an altered protein serologically related to β-Galactosids.
260 citations
Journal Article•
TL;DR: The data support the concept that the synthesis of DNA in the mammalian cell is a focalized phenomenon and that localized changes involving protein synthesis are required to initiate the replication process.
Abstract: Summary The initiation of DNA synthesis was studied in cultures of HeLa cells which were synchronized by the induction and timely reversal of a thymidineless state. It was observed that the synthesis of DNA was initiated at a slow rate but was more than doubled after 2 hours. This acceleration of DNA synthesis could be prevented with amounts of puromycin which simultaneously inhibited protein synthesis. Puromycin, however, did not inhibit DNA synthesis which was in progress at the time of addition, whereas its effects on protein synthesis were immediate. The data support the concept that the synthesis of DNA in the mammalian cell is a focalized phenomenon and that localized changes involving protein synthesis are required to initiate the replication process.
208 citations
TL;DR: By the use of suitable radioactive precursors for protein, DNA, and RNA, it was possible to examine and adapt the classical fractionation methods of Schmidt and Thannhauser and of Schneider to the membrane filter method.
104 citations
TL;DR: Various chemical and physiological aspects of the reproductive cycles of r+ and r strains of T2, T4, and T6 viruses have been examined and compared and the rates of DNA and protein synthesis in the infected cells were found to be independent of the viruses used.
Abstract: Various chemical and physiological aspects of the reproductive cycles of r+ and r strains of T2, T4, and T6 viruses have been examined and compared. These include the ultraviolet absorption spectra in which differences between r and r+ strains were not observed, though they were obtained in the case of T2, T4, and T6. Adsorption of T4 and T6 was found to require the adsorption cofactor l-tryptophane. Among the r and r+ strains of these viruses limiting tryptophane requirements for adsorption were found to be different. Some differences were observed in the one-step growth curves of these viruses under conditions of single and multiple infection. The turbidity-time relations of infected cultures were characteristically different. The rates of DNA and protein synthesis in the infected cells were found to be independent of the viruses used. Certain implications of the data have been discussed.
93 citations
TL;DR: It appears that ribosomal particles can limit the rate of protein synthesis and that the ribosomes which ultimately participate in the synthesis of a particular protein are present even when the protein is being made at a slow repressed rate.
58 citations