The effect of 5-fluorouracil-containing ribonucleic acid on protein synthesis by Escherichia coli in vivo

1963 ◽  
Vol 28 (5) ◽  
pp. 1215-1223 ◽  
Author(s):  
J. Černá ◽  
I. Rychlík ◽  
D. Grünberger ◽  
F. Šorm
1971 ◽  
Vol 124 (3) ◽  
pp. 537-541 ◽  
Author(s):  
D. P. Leader ◽  
I. G. Wool ◽  
J. J. Castles

The aminoacyltransferase I-catalysed binding of phenylalanyl-tRNA (unfractionated Escherichia coli B tRNA acylated with radioactive phenylalanine and 19 non-radioactive amino acids) to skeletal-muscle ribosomes from diabetic rats was less than that to ribosomes from normal rats when the Mg2+ concentration was low (7.5mm); whereas just the reverse was true when the concentration of the cation was higher (15mm). Thus the Mg2+ dependency of aminoacyltransferase I-catalysed binding of phenylalanyl-tRNA to ribosomes from normal and diabetic rats paralleled the effect of Mg2+ concentration on synthesis of polyphenylalanine reported before. During incubation at 7.5mm-Mg2+ phenylalanyl-tRNA was bound only to ribosomes bearing nascent peptidyl-tRNA. There are fewer such ribosomes in a preparation from the muscle of diabetic animals because diabetic animals synthesize less protein in vivo. Thus the difference in polyphenylalanine synthesis in vitro is adequately explained by the difference in enzyme-catalysed binding of phenylalanyl-tRNA to ribosomes, however, the basis of the difference in protein synthesis in vivo is still unknown.


Genetics ◽  
1979 ◽  
Vol 91 (2) ◽  
pp. 215-227
Author(s):  
W Scott Champney

ABSTRACT Two variations of the method of localized mutagenesis were used to introduce mutations into the 72 min region of the Escherichia coli chromosome. Twenty temperature-sensitive mutants, with linkage to markers in this region, have been examined. Each strain showed an inhibition of growth in liquid medium at 44°, and 19 of the mutants lost viability upon prolonged incubation at this temperature. A reduction in the rate of in vivo RNA and protein synthesis was observed for each mutant at 44°, relative to a control strain. Eleven of the mutants were altered in growth sensitivity or resistance to one or more of three ribosomal antibiotics. The incomplete assembly of ribosomal subunits was detected in nine strains grown at 44°. The characteristics of these mutants suggest that many of them are altered in genes for translational or transcriptional components, consistent with the clustering of these genes at this chromosomal locus.


2002 ◽  
Vol 364 (3) ◽  
pp. 857-862 ◽  
Author(s):  
Katarzyna POTRYKUS ◽  
Sylwia BARAŃSKA ◽  
Alicja WĘGRZYN ◽  
Grzegorz WĘGRZYN

Previous studies indicated during replication of plasmids derived from bacteriophage λ (the so-called λ plasmids), that, once assembled, replication complex can be inherited by one of the two daughter plasmid copies after each replication round, and may function in subsequent replication rounds. It seems that similar processes occur during replication of other DNA molecules, including chromosomes of the yeast Saccharomyces cerevisiae. However, apart from some suggestions based on genetic experiments, composition of the λ heritable replication complex remains unknown. In amino acid-starved Escherichia coli relA mutants, replication of λ plasmid DNA is carried out exclusively by the heritable replication complex as assembly of new complexes is impaired due to inhibition of protein synthesis. Here, using a procedure based on in vivo cross-linking, cell lysis, immunoprecipitation with specific sera, de-cross-linking and PCR analysis, we demonstrate that the λ heritable replication complex consists of O, P, DnaB and, perhaps surprisingly, DnaK proteins.


1965 ◽  
Vol 97 (1) ◽  
pp. 277-283 ◽  
Author(s):  
IA Holmes ◽  
DG Wild

1. During inhibition of Escherichia coli by chlortetracycline, protein synthesis was sharply reduced whereas synthesis of RNA was much less affected. 2. Most of the RNA made during inhibition was contained in particles that sedimented more slowly than ribosomes. 3. The particles were more sensitive than ribosomes to degradation by ultrasonic vibrations and ribonuclease and differed from ribosomes in their behaviour during chromatography on DEAE-cellulose. 4. The particles contained two species of RNA that differed slightly in their sedimentation properties from the two RNA components found in ribosomes. 5. The nature of the events taking place during inhibition by chlortetracycline is discussed with particular reference to the status of the particles that accumulate and to the mode of action of this and other antibiotics.


1979 ◽  
Vol 138 (3) ◽  
pp. 923-932 ◽  
Author(s):  
J J Collins ◽  
C R Alder ◽  
J A Fernandez-Pol ◽  
D Court ◽  
G S Johnson

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