Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.5.1.3 (dihydrofolate reductase)
 5,819 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to gain an insight into the distribution of resistance genes in Vibrio cholerae, we studied twenty-nine strains isolated from patients in Africa. Resistance to antibiotics in all strains except one was encoded by self-transferable plasmids belonging to incompatibility group Inc6-C. Tetracycline and chloramphenicol were poorly expressed in the original hosts but were easily detectable in the Escherichia coli transconjugants. Streptomycin resistance was due to synthesis of a 3"- or 6-aminoglycoside phosphotransferase. Based on MIC and hybridization data, high-level resistance to trimethoprim and O/129 was secondary to the presence of a dihydrofolate reductase of a new type, distantly related to type I activity. Our results confirm the presence in V. cholerae of beta-lactamases other than Tem-1.
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PMID:Genetic, biochemical and molecular characterization of strains of Vibrio cholerae multiresistant to antibiotics. 326 Jan 5

Streptomycin does not strongly inhibit T-even phage multiplication in the streptomycin-susceptible polyauxotroph, Escherichia coli strain T(-)H(-)U(-). The relatively slight inhibition, observed earlier, on production of late proteins has now been studied further. The phage-induced ribonucleic acid, synthesized in T6 phage infection in the presence of streptomycin, has been characterized by its base composition, size distribution, and behavior in hybridization tests. Comparison of these properties to those of control samples, taken during either early or late periods of infection, have not shown any significant differences. Phage-induced proteins, synthesized at different times during infection, were studied by disc-gel electrophoresis. Staining and autoradiography of the patterns of pulse-labeled proteins, formed in the absence and presence of the antibiotic showed only slight quantitative changes in the appearance of early proteins. More marked quantitative effects were detected later in infection. Nevertheless, changes in the mobilities of the different proteins were not observed in the streptomycin-treated cultures at any time after infection, suggesting the absence of gross misreading sufficiently great to alter the distinctive electrophoretic patterns of the extracts. Cells infected and incubated in the presence of the antibiotic were found to contain intact virus particles, as shown by electron microscopy. Such infected cells contained extensive deoxyribonucleic acid pools and did not develop the rounded nucleoids with enclosed dense bodies characteristic of the lethal action of the antibiotic. On the other hand, infected bacteria previously exposed to lethal concentrations of streptomycin were unable to synthesize the early enzymes, deoxycytidylate (dCMP) hydroxymethylase and dihydrofolate reductase, or to make phage deoxyribonucleic acid and phage. Such previously killed cells contained the rounded and clotted nucleoids and were unable to unravel this pathological structure after phage infection.
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PMID:T6r+-induced proteins and nucleic acids in Escherichia coli infected in the presence of streptomycin. 487 64