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Biomedical subjects

J E Dowding

Publications and source records attributed to J E Dowding.

6 recordsLinked to original sources

Susceptibility to butirosin and neomycin B in Bacillus circulans, the butirosin-producing organism.

Butirosin, an aminoglycoside antibiotic, is produced by Bacillus circulans B-3312. Experiments using recombined ribosomal and supernatant fractions from this strain and from B. megaterium KM have shown that the ribosome of both are sensitive to butirosin. The aminoglycoside 3'-phosphotransferase present in B. circulans modifies butirosin and neomycin in vitro but confers resistance only to the former in vivo. The phosphotransferase does not modifya detectable amount of extracellular butirosin while mediating resistance to the antibiotic. In vitro, however, the enzyme appears to protect against inhibition by butirosin by inactivating the bulk of the antibiotic in the system. An extrachromosomal element of unknown function has been detected in B. circulans.

Anti-Bacterial Agents↗

Mechanisms of gentamicin resistance in Staphylococcus aureus.

Three clinical isolates of Staphylococcus aureus resistant to gentamicin and other aminoglycosides have been examined for antibiotic modifying enzymes. The strains contain a number of these enzymes, most of them similar to those commonly found in aminoglycoside-resistant gram-negative strains. All three strains (and a transductant derived from one of them) contain two enzymes mediating gentamicin resistance, an aminoglycoside 6'-N-acetyltransferase and a novel enzyme, gentamicin phosphotransferase.

Acyltransferases↗