Metabolic effects of static magnetic fields on streptococcus pyogenes

Abstract

This study aimed to develop a simple experimental system utilising bacterial cells to investigate the dose responses resulting from exposures to static magnetic flux densities ranging from 0.05 to 0.5 T on viability, bacterial metabolism and levels of DNA damage in Streptococcus pyogenes. Exposure of S. pyogenes to a field of 0.3 T at 24 degrees C under anaerobic conditions resulted in a significant (P < 0.05) decrease in growth rate, with an increased mean generation time of 199 +/- 6 min compared to the control cells at 165 +/- 6 min (P < 0.05). Conversely, exposure to magnetic fields of 0.5 T significantly accelerated the growth rate at 24 degrees C compared to control cells, with a decreased mean generation time of 147 +/- 4 min (P < 0.05). The patterns of metabolite release from cells incubated in phosphate buffered saline (PBS) at 24 degrees C and exposed to different magnetic flux densities (0.05-0.5 T) were significantly (P < 0.05) altered, compared to non-exposed controls. Concentrations of metabolites, with the exception of aspartic acid (r = 0.44), were not linearly correlated with magnetic flux density, with all other r < 0.20. Instead, "window" effects were observed, with 0.25-0.3 T eliciting the maximal release of the majority of metabolites, suggesting that magnetic fields of these strengths had significant impacts on metabolic homeostasis in S. pyogenes. The exposure of cells to 0.3 T was also found to significantly reduce the yield of 8-hydroxyguanine in extracted DNA compared to controls, suggesting some possible anti-oxidant protection to S. pyogenes at this field strength.

Static magnetic field exposure fails to affect the viability of different bacteria strains

“…Our present finding, namely the lack of positive effect of SMFs on bacteria viability, supports the idea of Grosman et al [1992], Kohno et al [2000], Potenza et al [2004], and Gao et al [2005]. Even the results of Morrow et al [2007] could be verified because the flux density in the present experiment lay between 0.3 and 0.5 T. The growth inhibition found by Triampo et al [2004] may have been due to the special strain of bacteria used. In the case of Piatti et al [2002], the flux density was comparable to our measurements only on layers 2 and 3 of the iSMF arrangement.…”

“…Even the results of Morrow et al [2007] could be verified because the flux density in the present experiment lay between 0.3 and 0.5 T. The growth inhibition found by Triampo et al [2004] may have been due to the special strain of bacteria used. In the case of Piatti et al [2002], the flux density was comparable to our measurements only on layers 2 and 3 of the iSMF arrangement.…”

“…The strain was exposed to 14.1 T SMF for 12 h; the post-exposure growth was observed for another 18 h. They found no difference between treated and control cells in optical density, colony forming unit, or post-exposure growth of cells. Morrow et al [2007] used Streptococcus pyogenes to reveal a difference in growth rate between 0.3 and 0.5 T SMF exposure for 8 h and control. They correlated a significant decrease in growth rate to 0.3 T, and a significant increase to 0.5 T exposure, if the growth was under anaerobic conditions.…”

Influencia del campo magnético variable de onda sinusoidal de (22 – 52) khz y de 100 miligauss de inducción magnética, sobre el crecimiento de LACTOBACILLUS PLANTARUM utilizado como probiótico en alimentos

“…En el caso de los efectos en los microorganismos, estos se relacionan no solo con su especie y su morfología (Fojt et al, 2004;Fojt et al, 2009), sino también con las características del medio de cultivo (líquido o sólido) en el que reciben el tratamiento magnético (Barbosa et al, 2000). En ese sentido, se han estudiado más los efectos magnetobiológicos en medios de cultivo líquidos, utilizando técnicas indirectas como el recuento celular por densidad óptica o la cuantificación de un metabolito (Morrow et al, 2007).…”

Influencia del campo magnético sobre el crecimiento de microorganismos patógenos aislados ambiente del Archivo Nacional de la República de Cuba

“…En ese sentido, se han estudiado más los efectos magnetobiológicos en medios de cultivo líquidos, utilizando técnicas indirectas como el recuento celular por densidad óptica o la cuantificación de un metabolito (6).…”