The distinguishing effects of low-intensity electromagnetic radiation of different extremely high frequencies on Enterococcus hirae: growth rate inhibition and scanning electron microscopy analysis.

A low-intensity electromagnetic field of extremely high frequency has inhibitory and stimulatory effects on bacteria, including Enterococcus hirae. It was shown that the low-intensity (the incident power density of 0·06 mW cm-2 ) electromagnetic field at the frequencies of 51·8 GHz and 53 GHz inhibited E. hirae ATCC 9790 bacterial growth rate; a stronger effect was observed with 53 GHz, regardless of exposure duration (0·5 h, 1 h or 2 h). Scanning electron microscopy analysis of these effects has been done; the cells were of spherical shape. Electromagnetic field at 53 GHz, but not 51·8 GHz, changed the cell size-the diameter was enlarged 1·3 fold at 53 GHz. These results suggest the difference in mechanisms of action on bacteria for electromagnetic fields at 51·8 GHz and 53 GHz. SIGNIFICANCE AND IMPACT OF THE STUDY: A stronger inhibitory effect of low-intensity electromagnetic field on Enterococcus hirae ATCC 9790 bacterial growth rate was observed with 53 GHz vs 51·8 GHz, regardless of exposure duration. Scanning electron microscopy analysis showed that almost all irradiated cells in the population have spherical shapes similar to nonirradiated ones, but they have increased diameters in case of irradiated cells at 53 GHz, but not 51·8 GHz. The results are novel, showing distinguishing effects of low-intensity electromagnetic field of different frequencies. They could be applied in treatment of food and different products in medicine and veterinary, where E. hirae plays an important role.

Effects of the action of microwave-frequency electromagnetic radiation on the spike activity of neurons in the supraoptic nucleus of the hypothalamus in rats.

Acute experiments on white rats anesthetized with Nembutal (40 mg/kg, i.p.) were performed with extracellular recording and analysis of background spike activity from neurons in the supraoptic nucleus of the hypothalamus after exposure to electromagnetic radiation in the millimeter range. The distribution of neurons was determined in terms of the degree of regularity, the nature of the dynamics of neural streams, and the modalities of histograms of interspike intervals; the mean neuron spike frequency was calculated, along with the coefficient of variation of interspike intervals. These studies demonstrated changes in the background spike activity, predominantly affecting the internal structure of the spike streams recorded. The major changes were in the duration of interspike intervals and the degree of regularity of spike activity. Statistically significant changes in the mean spike frequencies of neuron populations in individual frequency ranges were also seen.