Resistance Factor-mediated Streptomycin Resistance
AUTOR(ES)
Harwood, J. H.
RESUMO
Resistance (R) factor-mediated streptomycin (Sm) resistance differs from classical, high-level, chromosome-borne Sm resistance in its dominance over sensitivity and in the level of its effectiveness (in Escherichia coli ∼25 μg/ml versus >2,000 μg/ml). In addition, an R factor-containing strain, unlike high-level Sm-resistant bacteria, showed an inoculum effect with respect to its level of Sm resistance. Crude extracts of this strain destroyed the inhibitory activity of Sm and bluensomycin (Blue) on in vitro protein synthesis. The ribosomes from this strain proved to be sensitive to Sm in vitro. The requirements for in vitro inactivation of Sm (and Blue) were determined to be: extract, adenosine triphosphate or deoxyadenosinetriphosphate, and Mg++. Chromatographic techniques with radioisotopes revealed the formation of an inactivated form of Sm containing adenosine (or deoxyadenosine), phosphate, and Sm in equimolar amounts. The adenylate moiety is coupled to the streptobiosamine residue, rather than to the streptidine ring, of the Sm molecule. The adenylating enzyme, which is not induced by Sm, is located in the periplasmic space of the R factor-containing strain.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=249843Documentos Relacionados
- Resistance Factor-Mediated Spectinomycin Resistance
- Mechanism of R factor-mediated chloramphenicol resistance.
- R Factor-Mediated Antibiotic Resistance in Serratia marcescens
- R Factor-Mediated and Chromosomal Resistance to Ampicillin in Escherichia coli
- Frequency of R Factor-mediated Multiple Drug Resistance in Klebsiella and Aerobacter