Low intensity infrared laser effects on Escherichia coli cultures and plasmid DNA.

Biostimulative effect of low intensity laser in tissues has been described on a photobiological basis and clinical protocols are recommended for treatment of various diseases. The aim of this work was to evaluate effects of laser exposure on the survival of Escherichia coli cultures and plasmid topological forms. Escherichia coli cultures and plasmids were exposed to infrared laser to study bacterial survival and electrophoretic profile, respectively. Data indicate low intensity infrared laser: (i) had no effect on E. coli wild type, endonuclease IV, exonuclease III, formamidopyrimidine DNA glycosylase/MutM protein and endonuclease III deficient cultures, but decreased the survival of E. coli UvrA protein deficient cultures; (ii) there was no alteration in the electrophoretic profile of plasmids. Exposure to low intensity infrared laser decreases survival of Escherichia coli cultures deficient in nucleotide excision repair of DNA and this effect could depend on fluences, wavelength and tissues conditions. [ABSTRACT FROM AUTHOR]