Recent data show that microwaves (MW) and extremely low-frequency (ELF) magnetic fields at low intensities affect conformation of nucleoids in bacterial E. coli cells and human lymphocytes. Experimental data suggest that magnitude of the effects of both MW and ELF depend on frequency and static magnetic field. We have previously proposed the physical model for the effects of combined ELF/static magnetic fields on the charged DNA-domain/nucleoid. In this article, we present the model of slow non uniform rotation of the charged DNA-domain/nucleoid for the combined effects of MW and static magnetic field. The solution of this model suggests that the combined action of MW and static magnetic field results in slow non uniform rotation of nucleoid with angular speed that depends on Larmor frequency. The model predicts that non thermal effects of MW are dependent on carrier frequency and also static magnetic field in the area of exposure.

The effects of weak magnetic fields of extremely low frequency (ELF) on E. coli K12 AB1157 cells were studied by the method of anomalous viscosity time dependencies (AVTD). E. coli cells at different densities within a range of 5 x 10(5)-10(9) cell/ml were exposed to ELF (sinusoidal, 30 microT peak, 15 min) at a frequency of 9 Hz. A transient effect with maximum 40-120 min after exposure was observed. Kinetics of the per-cell-normalised ELF effects fitted well to a Gaussian distribution for all densities during exposure. A maximum value of these kinetics and a time for this maximum were strongly dependent on the cell density during exposure. These data suggest a cell-to-cell interaction during response to ELF. Both dependencies had three regions close to a plateau within the ranges of 3 x 10(5) - 2 x 10(7) cell/ml, 4 x 10(7) - 2 x 10(8) cell/ml and 4 x 10(8)-10(9) cell/ml and two rather sharp transitions between these plateaus. The effect reached a maximum value at a density of 4 x 10(8) cell/ml. Practically no effect was observed at the lowest density of 3 x 10(5) cell/ml. The data suggested that the ELF effect was mainly caused by a secondary rather than a primary reaction. The filtrates from exposed cells neither induced significant AVTD changes in unexposed cells nor increased the ELF effect when were added to cells before exposure. The data did not provide evidence for significant contribution of stable chemical messengers, but some unstable compounds such as radicals could be involved in the mechanism of cell-to-cell interaction during response to ELF. The results obtained were also in accordance with a model based on an re-emission of secondary photons during resonance fluorescence.

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