Metabolic effects of static magnetic fields on streptococcus pyogenes

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 °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 °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 °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. Bioelectromagnetics 28:439–445, 2007. © 2007 Wiley‐Liss, Inc.