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Microbiology and Immunology 1980Various phenotypes of the resistance to aminoglycoside- and peptide-antibodies of Mycobacterium tuberculosis strain H37Rv were produced by single- and/or two-step...
Various phenotypes of the resistance to aminoglycoside- and peptide-antibodies of Mycobacterium tuberculosis strain H37Rv were produced by single- and/or two-step selection of the parent strain. Mutants obtained by single-step selection with antibiotics were classified into ten phenotypes; one of single resistance, two of triple resistance, three of quadruple resistance, and four of sextuple resistance. There were two kinds of sextuple resistance (high resistance to enviomycin, viomycin, capreomycin, kanamycin, lividomycin). One was isolated from the parent strain by single-step selection and could be eliminated by mutation to isoniazid resistance, the other was obtained by two-step selections and was not eliminated by mutation to isoniazid resistance. Interaction between mutation to streptomycin resistance and mutation to quadruple resistance (4R phenotype) was observed. Streptomycin resistance interfered with the formation of the 4R phenotype and produced a different phenotype, KR instead of the 4R phenotype. The existence of mutation of the 4R phenotype did not usually interfere with mutation to streptomycin resistance, but a small portion of the mutants with the 4R phenotype were altered in their phenotype from 4R to KR after addition of the mutation to streptomycin resistance. This effect of the mutation to streptomycin resistance was not observed in mutants which already had a mutation to klR phenotype (mutation to low concentrations of kanamycin only).
Topics: Aminoglycosides; Anti-Bacterial Agents; Drug Resistance, Microbial; Isoniazid; Mutation; Mycobacterium tuberculosis; Peptides; Phenotype; Streptomycin
PubMed: 6783817
DOI: 10.1111/j.1348-0421.1980.tb02883.x -
The Journal of Antibiotics Jun 1981The degrees of binding of [3H]dibekacin to LiCl-treated cores of E. coli ribosomes were reduced by increasing LiCl concentrations. The 1.15 M LiCl core lost 70...
The degrees of binding of [3H]dibekacin to LiCl-treated cores of E. coli ribosomes were reduced by increasing LiCl concentrations. The 1.15 M LiCl core lost 70 approximately 80% of the original binding capacity. The antibiotic attachment to the 1.15 M LiCl core was restored by reconstitution with the split proteins (SP), which were obtained by the treatment of 70S ribosomes with LiCl at concentrations of 0.8 approximately 1.15 M. The basic proteins, split off during the transition from 0.4 M LiCl core to 0.8 approximately 1.15 M LiCl core, seemed to be involved in the drug binding. SP0.4 approximately 1.15, which was obtained by the treatment of the 0.4 M LiCl core with 1.15 M LiCl, was fractionated by CM-Sephadex C-25 column chromatography, and each fraction was assayed for protein composition and the capability of restoring the ability of the 1.15 M LiCl core to bind the drug. Of ribosomal proteins eliminated with 1.15 M LiCl, the addition of either S9 or L6 alone to the 1.15 M LiCl core was observed to restore approximately 50% of the binding as compared to the 70S ribosome alone, and both proteins restored about 70% of the binding. The results suggested that ribosomal proteins S9 and L6 were involved in the attachment of [3H]dibekacin to the ribosome. The antibiotic binding to the 70S ribosome and 1.15 M LiCl core reconstituted with S9 and L6 was considerably inhibited by unlabelled dibekacin or kanamycin, and partially inhibited by gentamicin or neomycin, but was not significantly affected by streptomycin or viomycin.
Topics: Aminoglycosides; Anti-Bacterial Agents; Chlorides; Dibekacin; Escherichia coli; Kanamycin; Lithium; Lithium Chloride; Protein Binding; Ribosomal Protein S9; Ribosomal Proteins; Ribosomes
PubMed: 6268595
DOI: 10.7164/antibiotics.34.763 -
Journal of Bacteriology Oct 1976Competent Haemophilus influenzae Rd recipients, either as phage HP1 restricting (r+) or nonrestricting (r-) nonlysogens or defective lysogens, were exposed to...
Competent Haemophilus influenzae Rd recipients, either as phage HP1 restricting (r+) or nonrestricting (r-) nonlysogens or defective lysogens, were exposed to deoxyribonucleic acids from various wild-type phage HP1 lysogenic H. influenzae serotype strains (non-encapsulated derivatives of serotypes a,b, c, d, and e), to DNA from lysogenic Haemophilus parahaemolyticus, and to DNA from modified and nonmodified phage HP1. Transformation of antibiotic resistance markers and of prophage markers in homospecific crosses was observed to be unaffected by the recipient restriction phenotype, whereas the transfection response was much reduced in r+ recipients. Heterospecific transformation of prophage markers was reduced by only 80 to 90%, whereas antibiotic resistance marker transformation was 1,000 to 10,000 times lower. Heterspecific transfection was at least 100 times lower than homospecific transfection in both r+ and r- recipients. The general conclusion is that neither class I nor class II restriction enzymes affect significantly the transformation efficiency in homospecific and heterospecific crosses. The efficiency of heterospecific transformation may depend mainly on the deoxyribonucleic acid homology in the genetic marker region.
Topics: Bacteriophages; DNA Restriction Enzymes; Drug Resistance, Microbial; Endonucleases; Genes; Haemophilus influenzae; Lysogeny; Transformation, Genetic; Viomycin
PubMed: 185196
DOI: 10.1128/jb.128.1.212-220.1976 -
Biophysical Journal Nov 2007Adjacent transfer RNAs (tRNAs) in the A- and P-sites of the ribosome are in dynamic equilibrium between two different conformations called classical and hybrid states...
Adjacent transfer RNAs (tRNAs) in the A- and P-sites of the ribosome are in dynamic equilibrium between two different conformations called classical and hybrid states before translocation. Here, we have used single-molecule fluorescence resonance energy transfer to study the effect of Mg(2+) on tRNA dynamics with and without an acetyl group on the A-site tRNA. When the A-site tRNA is not acetylated, tRNA dynamics do not depend on [Mg(2+)], indicating that the relative positions of the substrates for peptide-bond formation are not affected by Mg(2+). In sharp contrast, when the A-site tRNA is acetylated, Mg(2+) lengthens the lifetime of the classical state but does not change the lifetime of the hybrid state. Based on these findings, the classical state resembles a state with direct stabilization of tertiary structure by Mg(2+) ions whereas the hybrid state resembles a state with little Mg(2+)-assisted stabilization. The antibiotic viomycin, a translocation inhibitor, suppresses tRNA dynamics, suggesting that the enhanced fluctuations of tRNAs after peptide-bond formation drive spontaneous attempts at translocation by the ribosome.
Topics: Biophysics; Fluorescence Resonance Energy Transfer; Ions; Magnesium; Models, Chemical; Nucleic Acid Conformation; Peptide Chain Elongation, Translational; Peptides; Polyethylene Glycols; Protein Transport; RNA, Transfer; RNA, Transfer, Amino Acyl; Ribosomes; Time Factors; Viomycin
PubMed: 17693476
DOI: 10.1529/biophysj.107.109884 -
FEBS Letters Jan 1992AcPhe2-tRNA(Phe) synthesized in 70S ribosomes after consecutive binding of AcPhe-tRNA(Phe) at the P sites and EF-Tu-directed binding of Phe-tRNA(Phe) at the A sites is...
AcPhe2-tRNA(Phe) synthesized in 70S ribosomes after consecutive binding of AcPhe-tRNA(Phe) at the P sites and EF-Tu-directed binding of Phe-tRNA(Phe) at the A sites is able to react quantitatively with puromycin in the absence of EF-G. A detailed study of the kinetics of the puromycin reaction, its comparison with that of spontaneous translocation, the use of antibiotic viomycin as an effective inhibitor of spontaneous translocation revealed that, besides spontaneous translocation, this peptidyl-tRNA could react with puromycin being located at the A site. This leads to the conclusion that the transpeptidation reaction per se triggers conformational changes in the ribosomal complex bringing the 3'-end of a newly synthesized peptidyl-tRNA nearer to the peptidyl-site of the peptidyltransferase center. This is detected functionally as the ability of such an A site bound peptidyl-tRNA to react with puromycin. This reaction is highly pronounced at elevated (25 degrees C) temperature but can be hardly detected at 0 degrees C.
Topics: Binding Sites; Models, Biological; Protein Biosynthesis; Puromycin; RNA, Transfer, Amino Acyl; RNA, Transfer, Phe; Ribosomes
PubMed: 1733779
DOI: 10.1016/0014-5793(92)80380-y -
Journal of Bacteriology Jan 1992Several versatile promoter-probe vectors have been constructed for Streptomyces strains which utilize the production of blue-green light as a measure of transcription...
Several versatile promoter-probe vectors have been constructed for Streptomyces strains which utilize the production of blue-green light as a measure of transcription activity. Three plasmid vectors (two high and one low copy number) and two transposons are described. The multicopy plasmids pRS1106 and pRS1108 contain a transcription terminator and multiple-cloning polylinker upstream of promoterless luciferase (lux) and neomycin resistance reporter genes. Plasmid pHI90 is similar in structure to the pRS vectors except that its single copy number is an advantage for regulation studies or situations in which overexpression is otherwise toxic to the cell. The two transposons carry a promoterless lux cassette cloned such that transposition into a target DNA and fusion to the target's transcription unit occur simultaneously. Tn5351 was created by inserting the luciferase genes near the right end of the viomycin resistance transposon Tn4563. Tn5353 carries the luciferase genes near the right end of a neomycin resistance transposon derived from Tn4556. The size of Tn5353 was minimized by deleting nonessential transposon sequences, making this element small enough to be cloned into phi C31 bacteriophages for efficient transposon delivery to target cells of Streptomyces strains. The two Tnlux transposons have been used to generate Streptomyces coelicolor morphological mutants and to monitor transcription from chromosomal promoters during development.
Topics: Chromosomes, Bacterial; Cloning, Molecular; DNA Probes; DNA Transposable Elements; Genetic Vectors; Luciferases; Mutation; Plasmids; Promoter Regions, Genetic; Recombination, Genetic; Streptomyces; Vibrio
PubMed: 1309525
DOI: 10.1128/jb.174.2.367-376.1992 -
Antimicrobial Agents and Chemotherapy Dec 1981The effects of 61 synthetic tuberactinomycin derivatives on polypeptide synthesis were tested in bacterial cell-free systems. Di-beta-lys-capreomycin IIA was more...
The effects of 61 synthetic tuberactinomycin derivatives on polypeptide synthesis were tested in bacterial cell-free systems. Di-beta-lys-capreomycin IIA was more effective than the natural product. Palmitoyl tuberactinamine N inhibited the growth of tuberactinomycin-resistant mutants and was not a ribosome inhibitor.
Topics: Anti-Bacterial Agents; Bacteria; Capreomycin; Drug Resistance, Microbial; Enviomycin; Mutation; Ribosomes; Viomycin
PubMed: 6173016
DOI: 10.1128/AAC.20.6.834 -
European Journal of Biochemistry Dec 1977
Topics: Escherichia coli; Guanosine Diphosphate; Guanosine Triphosphate; Kinetics; Peptide Chain Elongation, Translational; Peptide Elongation Factors; RNA, Transfer; Ribosomes; Viomycin
PubMed: 202460
DOI: 10.1111/j.1432-1033.1977.tb11974.x -
Nucleic Acids Research Dec 1980The requirements for the decoding process at the ribosomal A site have been investigated in the presence of viomycin. For these studies natural mRNA was replaced either... (Comparative Study)
Comparative Study
The requirements for the decoding process at the ribosomal A site have been investigated in the presence of viomycin. For these studies natural mRNA was replaced either by the synthetic oligonucleotide A-U-G(-U)n, with 0 less than or equal to n less than or equal to 4, or by a physical mixture of the oligonucleotides A-U-G and various oligo(U) sequences. Thus the effect of the "removal" of selected covalent bonds from the sequence A-U-G(U)n could be studied. When the ribosomal P site contains tRNAMetf, then normally the full hexanucleotide "messenger" A-U-G-U-U-U is needed for the EF-Tu-mediated binding of Phe-tRNA into the A site. However in presence of viomycin the pentanucleotide A-U-G-U-U suffices for this. It is also possible in the presence of viomycin to replace A-U-G-U and U-U. In all the above systems the binding of Phe-tRNA required the presence of EF-Tu and GTP. The results suggest that viomycin reinforces interactions between aa-tRNA and the A site after the codon-anticodon recognition step.
Topics: Anticodon; Binding Sites; Codon; Dipeptides; Escherichia coli; Oligoribonucleotides; RNA, Bacterial; RNA, Messenger; RNA, Transfer; RNA, Transfer, Amino Acyl; Ribosomes; Viomycin
PubMed: 6162154
DOI: 10.1093/nar/8.23.5813 -
Journal of Bacteriology Oct 1972Viomycin-resistant strains were isolated from Mycobacterium smegmatis. Ribosomes were isolated and tested for drug resistance in subcellular systems containing poly(U)...
Viomycin-resistant strains were isolated from Mycobacterium smegmatis. Ribosomes were isolated and tested for drug resistance in subcellular systems containing poly(U) as messenger ribonucleic acid. Resistance to viomycin in these strains was due to altered ribosomes. Further analysis showed that viomycin resistance of two mutants with low level resistance (20 mug/ml) was due to altered 30S ribosomal subunits. Another mutant that was highly resistant to viomycin (1 mg/ml), however, had altered 50S ribosomal subunits.
Topics: Bacterial Proteins; Carbon Isotopes; Cell-Free System; Centrifugation, Density Gradient; Drug Resistance, Microbial; Escherichia coli; Genetics, Microbial; Magnesium; Micropore Filters; Mutation; Mycobacterium; Peptide Biosynthesis; Phenylalanine; Poly U; RNA, Transfer; Ribosomes; Viomycin
PubMed: 4342812
DOI: 10.1128/jb.112.1.1-6.1972