Nitrogen laser irradiation (337 nm) causes temporary inactivation of clinical isolates of Mycobacterium tuberculosis

Dube, A and Jayasankar, K and Prabakaran, L and Kumar, V and Gupta, P K (2004) Nitrogen laser irradiation (337 nm) causes temporary inactivation of clinical isolates of Mycobacterium tuberculosis. Lasers in Medical Science, 19 (1). pp. 52-56. ISSN Print: 0268-8921; Onlnie: 1435-604X

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Abstract

We have investigated the effect of nitrogen laser irradiation (337 nm) on viability of clinical isolates of Mycobacterium tuberculosis. Bacteria were exposed to a nitrogen laser (average power 2.0 mW) in vitro at power density of 70 ± 0.7 W/m2 for 0-30 min, and the cell viability was determined by luciferase reporter phage (LRP) assay. Immediately after laser exposure, all the clinical isolates investigated showed a dose-dependent decrease in cell viability. However, when the laser-exposed isolates were incubated in broth medium for 3 days, most of these showed significant recovery from laser-induced damage. Addition of 5.0 μg/ml acriflavine (a DNA repair inhibitor) in the incubation medium had no significant effect on recovery. This suggests that DNA damage may not be involved in the cell inactivation. Electron paramagnetic resonance (EPR) studies using 5-doxy1 strearic acid (5-DS) as a probe suggest alterations in lipid regions of the cell wall. Implications of these results for understanding therapeutic effect of nitrogen laser on drug-resistant tuberculosis are discussed.

Item Type:	Article
Uncontrolled Keywords:	Cell inactivation, Laser, Luciferase, Luminescence, Tuberculosis, Ultraviolet light
Subjects:	Tuberculosis > Laboratory Research > Bacteriological
Divisions:	Basic Science Research > Bacteriology
Depositing User:	Dr. Rathinasabapati R
Date Deposited:	18 Nov 2013 08:10
Last Modified:	09 Mar 2016 10:09
URI:	http://eprints.nirt.res.in/id/eprint/638

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