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The Journal of Antibiotics May 2000The gene cluster encoding the deoxyoleandolide polyketide synthase (OlePKS) was isolated from the oleandomycin producing strain Streptomnyces antibioticus. Sequencing of...
The gene cluster encoding the deoxyoleandolide polyketide synthase (OlePKS) was isolated from the oleandomycin producing strain Streptomnyces antibioticus. Sequencing of the first two genes encoding OlePKS, together with the previously identified third gene revealed an overall genetic and protein architecture similar to that of the erythromycin gene cluster encoding the 6-deoxyerythronolide B synthase (DEBS) from Saccharopolyspora erythraea. When the entire OlePKS (10,487 amino acids) was expressed in the heterologous host Streptomyces lividans, it produced 8,8a-deoxyoleandolide, an aglycone precursor of oleandomycin. The role of the P-450 monooxygenase, OleP, in oleandomycin biosynthesis was also examined in vivo by co-expression with DEBS in S. lividans. The production of 8,8a-dihydroxy-6-deoxyerythronolide B and other derivatives indicates that OleP is involved in the epoxidation pathway of oleandomycin biosynthesis. Since there are currently no genetic systems available for manipulation of the natural oleandomycin producing strain, the heterologous expression system reported here provides a useful tool for studying this important macrolide antibiotic.
Topics: Anti-Bacterial Agents; Base Sequence; Cloning, Molecular; DNA Primers; Epoxy Compounds; Genes, Bacterial; Multienzyme Complexes; Multigene Family; NADH, NADPH Oxidoreductases; NADPH-Ferrihemoprotein Reductase; Oleandomycin; Streptomyces
PubMed: 10908114
DOI: 10.7164/antibiotics.53.502 -
Antimicrobial Agents and Chemotherapy Feb 2007The gram-negative soil bacillus Burkholderia pseudomallei is the causative agent of melioidosis, a severe and potentially fatal septicemic disease that is endemic to...
The gram-negative soil bacillus Burkholderia pseudomallei is the causative agent of melioidosis, a severe and potentially fatal septicemic disease that is endemic to Southeast Asia and northern Australia. Its intrinsic resistance to many antibiotics is attributed mainly to the presence of several drug efflux pumps, and therefore, inhibitors of such pumps are expected to restore the activities of many clinically important antimicrobial agents that are the substrates of these pumps. The phenothiazine antipsychotic and antihistaminic drugs prochlorperazine, chlorpromazine, and promazine have a synergistic interaction with a wide spectrum of antimicrobial agents, thereby enhancing their antimicrobial potency against B. pseudomallei. Antimicrobial agents that interacted synergistically with the phenothiazines include streptomycin, erythromycin, oleandomycin, spectinomycin, levofloxacin, azithromycin, and amoxicillin-clavulanic acid. The MICs of these antibiotics were reduced as much as 8,000-fold in the presence of the phenothiazines. Antimicrobial agents which did not interact synergistically with the phenothiazines include gentamicin, amoxicillin, and ampicillin. Omeprazole, a proton pump inhibitor, provided an augmentation of antimicrobial activities similar to that of the phenothiazines, suggesting that the phenothiazines might have interfered with the proton gradient at the inner membrane. B. pseudomallei cells accumulated more erythromycin in the presence of the phenothiazines, an effect similar to that of carbonyl cyanide m-chlorophenylhydrazone, a proton gradient uncoupler. In the presence of the phenothiazines, a much reduced concentration of erythromycin (0.06x MIC) also protected human lung epithelial cells and macrophage cells from B. pseudomallei infection and attenuated its cytotoxicity.
Topics: Anti-Infective Agents; Burkholderia pseudomallei; Cells, Cultured; Drug Synergism; Humans; Lung; Macrophages; Melioidosis; Microbial Sensitivity Tests; Phenothiazines; Proton Pump Inhibitors
PubMed: 17145801
DOI: 10.1128/AAC.01033-06 -
Journal of Bacteriology Feb 1978The genetics of antibiotic resistance in mutant strains of Streptococcus pyrogenes was studied. Utilizing a type 6 strain (9440) primarily resistant to strepttomycin...
The genetics of antibiotic resistance in mutant strains of Streptococcus pyrogenes was studied. Utilizing a type 6 strain (9440) primarily resistant to strepttomycin (Strr), classes of mutant strains were isolated that were resistant to one of the following antibiotics: rifampin (Rifr), erythromycin (Eryr), thiostrepton (Tstr), spiramycin (Sprr), fusidic acid (Fusr), gramicidin (Grcr), ethidium bromide (Ebrr), kanamycin (Kanr), neomycin (Neor), oleandomycin (Oler), gentamicin (Genr), and novobiocin (Novr). Transduction experiments separated antibiotic resistance markers into two distinct groups: transducible markers, including Fusr, Bacr, Ksg+, Spcr, Eryr, Sprr, Rifr, Stlr, and Tstr (Bacr, Ksgr, Spcr, and Stlr refer to resistance to bacitracin, kasugamycin, spectinomycin, and streptolydigan, respectively), and nontransducible markers, including Grcr, Ebrr, Kanr, Neor, Oler, Genr, and Novr. By means of two- and three-point crosses, transducible markers (excluding tst) were located in three separate linkage groups. spr was found to be linked with ery and spc in the order spc-ery-spr, whereas in a separate linkage group the order was determined to be str-fus-bac-ksg. The third linkage group contained the rif and stl markers.
Topics: Anti-Bacterial Agents; Chromosome Mapping; Crosses, Genetic; Drug Resistance, Microbial; Genetic Linkage; Streptococcus pyogenes; Streptomycin; Transduction, Genetic
PubMed: 342510
DOI: 10.1128/jb.133.2.852-859.1978 -
Molecular Microbiology Dec 1999Two glycosyltransferase genes, oleG1 and oleG2, and a putative isomerase gene, oleP1, have previously been identified in the oleandomycin biosynthetic gene cluster of...
Interspecies complementation in Saccharopolyspora erythraea : elucidation of the function of oleP1, oleG1 and oleG2 from the oleandomycin biosynthetic gene cluster of Streptomyces antibioticus and generation of new erythromycin derivatives.
Two glycosyltransferase genes, oleG1 and oleG2, and a putative isomerase gene, oleP1, have previously been identified in the oleandomycin biosynthetic gene cluster of Streptomyces antibioticus. In order to identify which of these two glycosyltransferases encodes the desosaminyltransferase and which the oleandrosyltransferase, interspecies complementation has been carried out, using two mutant strains of Saccharopolyspora erythraea, one strain carrying an internal deletion in the eryCIII (desosaminyltransferase) gene and the other an internal deletion in the eryBV (mycarosyltransferase) gene. Expression of the oleG1 gene in the eryCIII deletion mutant restored the production of erythromycin A (although at a low level), demonstrating that oleG1 encodes the desosaminyltransferase required for the biosynthesis of oleandomycin and indicating that, as in erythromycin biosynthesis, the neutral sugar is transferred before the aminosugar onto the macrocyclic ring. Significantly, when an intact oleG2 gene (presumed to encode the oleandrosyltransferase) was expressed in the eryBV deletion mutant, antibiotic activity was also restored and, in addition to erythromycin A, new bioactive compounds were produced with a good yield. The neutral sugar residue present in these compounds was identified as L-rhamnose attached at position C-3 of an erythronolide B or a 6-deoxyerythronolide B lactone ring, thus indicating a relaxed specificity of the oleandrosyltransferase, OleG2, for both the activated sugar and the macrolactone substrate. The oleP1 gene located immediately upstream of oleG1 was likewise introduced into an eryCII deletion mutant of Sac. erythraea, and production of erythromycin A was again restored, demonstrating that the function of OleP1 is identical to that of EryCII in the biosynthesis of dTDP-D-desosamine, which we have previously proposed to be a dTDP-4-keto-6-deoxy-D-glucose 3, 4-isomerase.
Topics: Chromatography, High Pressure Liquid; Chromatography, Thin Layer; DNA, Bacterial; Erythromycin; Genes, Bacterial; Genetic Complementation Test; Glycosyltransferases; Isomerases; Magnetic Resonance Spectroscopy; Mass Spectrometry; Multigene Family; Oleandomycin; Plasmids; Saccharopolyspora; Streptomyces antibioticus; Transformation, Bacterial
PubMed: 10594828
DOI: 10.1046/j.1365-2958.1999.01666.x -
Journal of Bacteriology Jun 1963Brown, Ruby L. (North Carolina State College, Raleigh) and James B. Evans. Comparative physiology of antibiotic-resistant strains of Staphylococcus aureus. J. Bacteriol....
Brown, Ruby L. (North Carolina State College, Raleigh) and James B. Evans. Comparative physiology of antibiotic-resistant strains of Staphylococcus aureus. J. Bacteriol. 85:1409-1412. 1963.-A collection of antibiotic-resistant strains of Staphylococcus aureus isolated from clinical sources was studied with respect to nutritional requirements and common diagnostic tests. Contrary to numerous reports in the literature indicating changes in these characteristics in antibiotic-resistant mutants, the present cultures were typical members of the taxonomic species S. aureus. They were coagulase-positive, fermented both glucose and mannitol under anaerobic conditions, produced acetoin from glucose, grew and produced black colonies on tellurite glycine agar, required both thiamine and nicotinic acid, and did not require other vitamins or purines. It is suggested that in most instances these cultures from clinical sources represent spontaneous mutants having genetic changes limited largely to loci concerned with antibiotic resistance. Most reports of extensive changes in physiology and nutritive requirements by antibiotic-resistant strains of S. aureus are based on studies of resistant strains selected after exposing a large population of the parent sensitive strain to toxic levels of antibiotics, chemical mutagens, or irradiation. Such isolates may have widespread genetic damage at other loci in addition to those concerned with their antibiotic resistance.
Topics: Anti-Bacterial Agents; Chloramphenicol; Coagulase; Drug Resistance, Microbial; Erythromycin; Glucose; Humans; Hydrolases; Mannitol; Metabolism; Micrococcus; Neomycin; Niacin; Nicotinic Acids; Novobiocin; Oleandomycin; Penicillins; Pyruvates; Research; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus; Streptomycin; Tetracycline; Thiamine
PubMed: 14047237
DOI: 10.1128/jb.85.6.1409-1412.1963 -
Antimicrobial Agents and Chemotherapy Mar 1974Antibiotics were used as probes of ribosome topology and function. Studies of [(14)C]chloramphenicol and [(14)C]erythromycin binding to ribosomes and polyribosomes...
Antibiotics were used as probes of ribosome topology and function. Studies of [(14)C]chloramphenicol and [(14)C]erythromycin binding to ribosomes and polyribosomes revealed the following features. The requirement of high K(+) concentration (150 mM) for [(14)C]chloramphenicol binding to NH(4)Cl-washed ribosomes resulted from the washing procedure. Neither native 70S ribosomes nor polyribosomes require K(+) greater than 30 mM for [(14)C]chloramphenicol binding. Whereas [(14)C]chloramphenicol binds to both ribosomes and polyribosomes, [(14)C]erythromycin binds essentially only to ribosomes. After removal of peptidyl-transfer ribonucleic acid (tRNA) from polyribosomes, [(14)C]erythromycin could then be bound. The effects of a number of antibiotics on [(14)C]chloramphenicol binding to ribosomes and polyribosomes was assessed. It was found that most of the macrolides (erythromycin, carbomycin, spiramycin III, niddamycin, oleandomycin, and tylosin) and streptogramins A and B (vernamycin A, PA114A, vernamycin Balpha, and PA114B) inhibited chloramphenicol binding to NH(4)Cl-washed and native 70S ribosomes, but not to polyribosomes. After removal of peptidyl-tRNA from polyribosomes, [(14)C]chloramphenicol binding was then inhibited. In contrast, sparsomycin and althiomycin inhibited chloram-phenicol binding to polyribosomes, but not to ribosomes. After removal of peptidyl-tRNA from polyribosomes, sparsomycin and althiomycin were then ineffective. The presence of peptidyl-tRNA on polyribosomes apparently is required for binding of sparsomycin and althiomycin, but prevents binding of most macrolides and streptogramins. The lincosaminides (lincomycin and celesticetin) and methymycin (a small macrolide) inhibited [(14)C]chloramphenicol binding to NH(4)Cl-washed and native 70S ribosomes best, but also inhibited the binding to polyribosomes. The amino nucleosides and other antibiotics tested do not seem to interact strongly with the major chloramphenicol-binding site. These results provide knowledge of the interrelationships between antibiotic and substrate ribosome binding sites which should eventually contribute to a map of ribosomal topology.
Topics: Anti-Bacterial Agents; Carbon Radioisotopes; Chloramphenicol; Erythromycin; Escherichia coli; Magnesium; Polyribosomes; Potassium; Puromycin; Ribosomes
PubMed: 4599122
DOI: 10.1128/AAC.5.3.255 -
Open Veterinary Journal 2011Bacterial isolates from 30 farmed bullfrogs (Lithobates catesbeianus) weighing 500-600 g at Johore, Malaysia with external clinical signs of ulcer, red leg and...
Bacterial isolates from 30 farmed bullfrogs (Lithobates catesbeianus) weighing 500-600 g at Johore, Malaysia with external clinical signs of ulcer, red leg and torticollis were tested for their antibiograms and heavy metal tolerance patterns. A total of 17 bacterial species with 77 strains were successfully isolated and assigned to 21 antibiotics and 4 types of heavy metal (Hg(2+), Cr(6+), Cd(2+), Cu(2+)). Results revealed that bacteria were resistant against lincomycin (92%), oleandomycin (72.7%) and furazolidone (71.4%) while being susceptible to chloramphenicol and florfenicol at 97.4%. The multiple antibiotic resistance (MAR) index for C. freundii, E. coli and M. morganii was high with the value up to 0.71. Bacterial strains were found to exhibit 100 % resistance to chromium and mercury. High correlation of resistance against both antibiotics and heavy metals was found (71.4 to 100%) between bullfrog bacteria isolates, except bacteria that were resistant to kanamycin showed only 25% resistance against Cu(2+). Based on the results in this study, bacterial pathogens of bullfrog culture in Johore, Malaysia, were highly resistant to both antibiotics and heavy metals.
PubMed: 26623279
DOI: No ID Found -
The Journal of Antibiotics Nov 1970
Topics: Amphotericin B; Animals; Anti-Bacterial Agents; Antifungal Agents; Cell Line; Chick Embryo; Chloramphenicol; Cycloserine; HeLa Cells; Kanamycin; Leucomycins; Mice; Microbial Sensitivity Tests; Mitomycins; Mycoplasma; Mycoplasma Infections; Nystatin; Oleandomycin; Oligomycins; Penicillins; Polymyxins; Puromycin; Streptomycin; Tetracycline
PubMed: 4321093
DOI: 10.7164/antibiotics.23.531 -
The Tohoku Journal of Experimental... Apr 1968
Topics: Adult; Betamethasone; Bone Marrow Examination; Chloramphenicol; Cytoplasm; Eosinophils; Hemorrhage; Humans; Kidney; Liver; Lymph Nodes; Lymphatic Diseases; Male; Oleandomycin; Pancreas; Reticulocytes; Spleen; Tetracycline
PubMed: 5671799
DOI: 10.1620/tjem.94.351 -
Bulletin of the World Health... 1967About 1500 strains of El Tor vibrios, isolated in 1964 and 1965 in the Philippines, were examined for their susceptibilities to 17 drugs. All the strains tested were...
About 1500 strains of El Tor vibrios, isolated in 1964 and 1965 in the Philippines, were examined for their susceptibilities to 17 drugs. All the strains tested were highly sensitive to dihydroxymethyl-furalazine, and most were highly sensitive to tetracycline hydrochloride, chloramphenicol and erythromycin, and moderately sensitive to novobiocin, dihydrostreptomycin sulfate, kanamycin and neomycin. They showed a remarkable fluctuation of sensitivity to ampicillin, cefaloridine, cefalotin and sulfafurazole, and a high resistance to benzylpenicillin sodium, oleandomycin and spiramycin.Experimental confirmation was provided of the fact that El Tor vibrios and non-agglutinable vibrios can be distinguished from classical cholera vibrios by their resistance to polymyxin B and colistin.Highly streptomycin-resistant strains, and to a lesser extent ampicillin- and sulfafurazole-resistant strains, were relatively often isolated from cholera patients who had been treated with antibiotics. One patient yielded a strain resistant to tetracycline, chloramphenicol, streptomycin and sulfafurazole.
Topics: Anti-Bacterial Agents; Bacteriological Techniques; Drug Resistance, Microbial; Philippines; Vibrio
PubMed: 4870079
DOI: No ID Found