Lucas Kiyoshi da Fonseca Iwahara1, Flavia de Paoli2, Adenilson de Souza da Fonseca3,4,5. 1. Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro, Avenida Pasteur, 296, Urca, Rio de Janeiro, 22290240, Brazil. 2. Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Rua José Lourenço Kelmer, s/n - Campus Universitário, São Pedro, Juiz de Fora, Minas Gerais, 36036900, Brazil. 3. Laboratório de Biofotônica, Departamento de Biofísica e Biometria, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Boulevard Vinte e Oito de Setembro, 87, fundos, 4º andar, Vila Isabel, Rio de Janeiro, 20551030, Brazil. 4. Departamento de Ciências Fisiológicas, Instituto Biomédico, Universidade Federal do Estado do Rio de Janeiro, Rua Frei Caneca, 94, Rio de Janeiro, 20211040, Brazil. 5. Centro de Ciências da Saúde, Centro Universitário Serra dos Órgãos, Avenida Alberto Torres, 111, Teresópolis, Rio de Janeiro, 25964004, Brazil.
Abstract
Introduction: Low-level lasers are successfully used to prevent and treat diseases in soft oral and bone tissues, particularly diseases in oral cavity caused by chemotherapy and radiotherapy in oncology. However, controversy exists as to whether these lasers induce molecular side effects, mainly on DNA. The aim of this work was to assess the effects of low-power lasers on mutant Escherichia coli cells in DNA repair. Methods: Escherichia coli wild type cultures as well as those lacking recombination DNA repair (recA -) and la SOS responses (lexA -) irradiated with lasers at different energy densities, powers, and emission modes for cell viability and morphology assessment were used in this study. Results: Laser irradiation: (i) did not affect cell viability of non-mutant and lexA - cells but decreased viability in recA - cultures; (ii) altered morphology of wild type and lexA, depending on the energy density, power, emission mode, and wavelength. Conclusion: Results show that low-level lasers have lethal effects on both recombination DNA repair and SOS response bacterial cells but do not induce morphological modifications in these cells.
Introduction: Low-level lasers are successfully used to prevent and treat diseases in soft oral and bone tissues, particularly diseases in oral cavity caused by chemotherapy and radiotherapy in oncology. However, controversy exists as to whether these lasers induce molecular side effects, mainly on DNA. The aim of this work was to assess the effects of low-power lasers on mutant Escherichia coli cells in DNA repair. Methods:Escherichia coli wild type cultures as well as those lacking recombination DNA repair (recA -) and la SOS responses (lexA -) irradiated with lasers at different energy densities, powers, and emission modes for cell viability and morphology assessment were used in this study. Results: Laser irradiation: (i) did not affect cell viability of non-mutant and lexA - cells but decreased viability in recA - cultures; (ii) altered morphology of wild type and lexA, depending on the energy density, power, emission mode, and wavelength. Conclusion: Results show that low-level lasers have lethal effects on both recombination DNA repair and SOS response bacterial cells but do not induce morphological modifications in these cells.
Authors: Adenilson S Fonseca; Thiago O Moreira; Deise L Paixão; Fernanda M Farias; Oscar R Guimarães; Severo de Paoli; Mauro Geller; Flavia de Paoli Journal: Lasers Surg Med Date: 2010-08 Impact factor: 4.025