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Bioreduction of Tempone and spin-labeled gentamicin by gram-negative bacteria: kinetics and effect of ultrasound.
- Source :
-
Archives of biochemistry and biophysics [Arch Biochem Biophys] 1999 Feb 15; Vol. 362 (2), pp. 233-41. - Publication Year :
- 1999
-
Abstract
- The primary objective of this study is the investigation of bioreduction kinetics of hydrophilic spin probes, 2,2,6,6, -tetramethyl-4-oxo-piperidinyl-1-oxyl (Tempone), and spin-labeled antibiotic gentamicin by gram-negative bacteria maintained at various oxygen tensions, with emphasis on the effect of probe penetration rate. This information was used to evaluate the effect of ultrasound on the penetration of hydrophilic compounds, including antibiotics, into Pseudomonas aeruginosa and Escherichia coli cells. Penetration of spin-labeled compounds into the cells was assessed by the reduction rate of the nitroxyl moiety measured by EPR. In cell suspensions, both Tempone and spin-labeled gentamicin were localized predominantly in the aqueous phase surrounding the cells. However, a gradual reduction of the probes in contact with the cells indicated that the probes penetrated through the outer membrane and periplasmic space into the cytoplasmic membrane, where the electron transport chains and other metabolic activities of gram-negative bacteria are localized. The kinetics of probe reduction depended on oxygen tension and presence of electron transport chain blockers. It was found that probe penetration rate through the outer cell membrane affected the rate of probe reduction; damaging the permeability barrier by cell incubation with EDTA or by powerful insonation above the cavitation threshold increased the rate of probe reduction. In contrast, insonation below the cavitation threshold did not affect the rate of probe reduction. These findings imply that the recently observed synergistic effect between hydrophilic antibiotics and low frequency ultrasound in killing gram-negative bacteria did not result from the enhanced antibiotic penetration through bacterial cell walls.<br /> (Copyright 1999 Academic Press.)
- Subjects :
- Cell Membrane drug effects
Cell Membrane metabolism
Cell Membrane Permeability drug effects
Cell Wall drug effects
Cell Wall metabolism
Edetic Acid pharmacology
Electron Spin Resonance Spectroscopy
Electron Transport drug effects
Escherichia coli drug effects
Kinetics
Nitrogen metabolism
Nitrogen Oxides metabolism
Oxidation-Reduction drug effects
Oxygen metabolism
Periplasm drug effects
Periplasm metabolism
Pseudomonas aeruginosa drug effects
Sodium Azide pharmacology
Vitamin K pharmacology
Escherichia coli metabolism
Gentamicins metabolism
Pseudomonas aeruginosa metabolism
Sonication
Spin Labels
Triacetoneamine-N-Oxyl metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0003-9861
- Volume :
- 362
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Archives of biochemistry and biophysics
- Publication Type :
- Academic Journal
- Accession number :
- 9989932
- Full Text :
- https://doi.org/10.1006/abbi.1998.1020