Influence of light coherence on the phytochrome-mediated responses of bacterial cells

This study investigates the impact of light coherence on the photoinduced response of the bacteria Pseudomonas fluorescens. A cell suspension was exposed to brief periods of irradiation in the excitation region of the direct or reverse phyB photoconversion. Quasi-monochromatic radiation fluxes with equal intensity but different spatial and temporal coherence were formed in each spectral range. The effect of light exposure was judged by the number of cells in the fixed (0.06 mm²) field of view during microscopy of the suspension preparations. Photon correlation is shown to affect the photoinduced response of bacteria in both direct and reverse phyB photoconversion. The discovered effect can be used for selective control of the functional activity of prokaryotic cells.