Effects of 50 Hz electric currents and magnetic fields on the prokaryote Propionibacterium acnes

Abstract

The effects of 50 Hz sinusoidal electric currents and magnetic fields on the Gram-positive skin bacterium Propionibacterium acnes were investigated. Intracellular free calcium ([Ca(2+)](i)), intracellular pH (pH(i)), and cell viability were examined, based on their relevance to ELF field studies and on previous studies conducted on P. acnes (UVA irradiation, photosensitization using porphyrin-based sensitizers, and broad-band red light). The [Ca(2+)](i) and the pH(i) were measured spectrofluorimetrically using the fluorescent probes fura-2 and BCECF, respectively. Sham-exposed controls were used to assess the field exposed samples. Cell suspensions were exposed to 50 Hz, 0.2 mT sinusoidal magnetic fields generated by using Helmholtz coils for up to 30 min. The estimated maximum induced electric field was 0.2 mV/m. Changes in [Ca(2+)](i) and cell viability were not detected. Ag/AgCl electrodes were used to expose cell suspensions to 50 Hz sinusoidal electric currents. The current densities were in the range 0.015-1500 A/m(2) (corresponding electric fields congruent with0.01-1000 V/m). Changes in [Ca(2+)](i) were not observed after current exposure. Current densities of 800 A/m(2) (electric field E congruent with550 V/m) were required for a 50% reduction in cell viability. Current densities greater than 800 A/m(2) were required for a reduction in pH(i). However, a pH gradient across the cell membrane (inside alkaline) was maintained even when exposure resulted in less than 0. 2% survival (1400 A/m(2), E congruent with950 V/m). Thus, dissipation of the pH gradient across the cell membrane and changes in [Ca(2+)](i) were not a consequence of cell inactivation by 50 Hz electric currents. This is in contrast to inactivation of P. acnes by UVA irradiation or photosensitization, where such changes have been obtained.

Effects of extremely‐low‐frequency pulsed electromagnetic fields on collagen synthesis in rat skin

“…However, due to the specificity of biological processes, it is most likely that a specific set of frequency and intensity would cause a favourable biological response. In the present study, we investigated the effects of ELF‐PEMF on the synthesis of collagen in rat skin at some frequencies and field intensities [16,17].…”

“…The experiments were designed to employ the field parameter setting of about 2 mT and 50 Hz. The intensity levels of 1 and 4 mT and the frequencies of 25 and 100 Hz are (one‐half) and (double), the field parameter settings (2 mT and 50 Hz) that have been used by other investigators [16,17]. Therefore the experiments for the field settings of (2 mT and 25 Hz), (2 mT and 50 Hz) and (2 mT and 100 Hz) were carried out.…”

Amplitude Modulated Waves as a Promising Tool for Food Preservation

“…Recently, the possible use of electromagnetic waves for inhibiting fungal growth have been investigated and proofed in many studies (Ramsted et al, 2000;Zhang et al, 2002;Rizk, 2003;Fadel et al, 2009;Bamidele et al, 2012;Ivona et al, 2015). Electromagnetic waves are nonionizing radiation proved to affect some physiological activities of living organisms (Piskorz-Binczycka et al, 2003;Maxim et al, 2004;Aronsson et al, 2005).…”