title: Low-intensity electromagnetic irradiation of 70.6 and 73 GHz frequencies enhances the effects of disulfide bonds reducer on Escherichia coli growth and affects the bacterial surface oxidation-reduction state.
abstract: Low-intensity electromagnetic irradiation (EMI) of 70.6 and 73 GHz frequencies (flux capacity - 0.06 mW cm(-2)) had bactericidal effects on Escherichia coli. This EMI (1h) exposure suppressed the growth of E. coli K-12(λ). The pH value (6.0-8.0) did not significantly affect the growth. The lag-phase duration was prolonged, and the growth specific rate was inhibited, and these effects were more noticeable after 73 GHz irradiation. These effects were enhanced by the addition of DL-dithiothreitol (DTT), a strong reducer of disulfide bonds in surface membrane proteins, which in its turn also has bactericidal effect. Further, the number of accessible SH-groups in membrane vesicles was markedly decreased by EMI that was augmented by N,N'-dicyclohexycarbodiimide and DTT. These results indicate a change in the oxidation-reduction state of bacterial cell membrane proteins that could be the primary membranous mechanism in the bactericidal effects of low-intensity EMI of the 70.6 and 73 GHz frequencies.
authors.affiliation: Department of Biophysics of Biology Faculty, Yerevan State University, Yerevan 0025, Armenia.
authors.forename: Heghine
authors.initials: H
authors.lastname: Torgomyan
authors.forename: Armen
authors.initials: A
authors.lastname: Trchounian
mesh_terms: D002462:Cell Membrane / Q000378:metabolism / Q000528:radiation effects*; D004024:Dicyclohexylcarbodiimide / Q000737:chemistry / Q000494:pharmacology; D004229:Dithiothreitol / Q000737:chemistry / Q000494:pharmacology; D060733:Electromagnetic Radiation; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects*; D008565:Membrane Proteins / Q000737:chemistry; D010084:Oxidation-Reduction / Q000528:radiation effects
chemical_list: D008565:Membrane Proteins; D004024:Dicyclohexylcarbodiimide; D004229:Dithiothreitol