Regularities of separate and combined effects of circularly polarized millimeter waves on E. coli cells at different phases of culture growth

Abstract

The method of anomalous viscosity time dependence (AVTD) was used to study the separate and combined effects of circularly polarized electromagnetic radiation (EMR) on the genome conformational state of E. coli cells. The bacterial cells at different phases of culture growth were exposed separately to right-handed polarized (RP) and left-handed polarized (LP) EMR (100 μW cm −2) at the resonance frequency (51.76 GHz), and to the combined influence of EMR in different sequences. It was shown that the value and sign of the effect depend strongly on the growth phase. The effect changes its sign in all variants of exposure, including exposure to linearly polarized EMR at another resonance frequency (41.32 GHz), at the transition from the logarithmic to the stationary growth phase. Variations in a spectrum of polypeptides bound to chromosomal DNA and their relation with changes in AVTD were shown by means of electrophoresis. The combined effect of circularly polarized millimeter waves on intact cells and on cells exposed to X-radiation is not additive; the effect depends most strongly on the sequence of cell exposure to LP and RP EMR.