Two different mechanisms of low-intensity laser photobiological effects on Escherichia coli.

Bacterial suspensions in a phosphate buffer were irradiated at wavelengths lambda of 632.8, 1066 and 1286 nm, incubated in Hottinguer broth for 60 min and assayed for viability by the standard surface-plating technique. The difference between the number of viable cells in the irradiated culture and the control was termed growth stimulation.

Comparison of the effects of visible femtosecond laser pulses and continuous wave laser radiation of low average intensity on the clonogenicity of Escherichia coli.

To evaluate the contribution of local pulsed heating of light-absorbing microregions to biochemical activity, irradiation of Escherichia coli was carried out using femtosecond laser pulses (lambda = 620 nm, tau p = 3 x 10(-13) S, fp = 0.5 Hz, Ep = 1.1 x 10(-3) J cm-2, Iav = 5.

Action of low-intensity laser radiation on Escherichia coli.

The review deals with quantitative laws of monochromatic visible light action on the cellular level, as well as with the primary photoacceptors and possible light signal transduction chains in bacterial cell Escherichia coli WP2 trp-. Experiments described in this paper are a part of experimental work performed for explaining the molecular mechanism of low-intensity laser therapy. The existence of certain parameters of light (dose, intensity, pulse repetition rate, monochromaticity within the absorbtion bandwidth of biomolecules) for stimulation of E.

Role of primary photoacceptors in low-power laser effects: action of He-Ne laser radiation on bacteriophage T4-Escherichia coli interaction.

The effect of He-Ne laser radiation (lambda = 632.8 nm) on bacteriophage T4-Escherichia coli WP2 interactions was studied. Irradiation of bacteria having respiratory chain components as primary photoacceptors accelerated their division in a dose-dependent manner, but irradiation had no effect on the properties of the phage (measured as its ability to infect host cells).