Effects of combined magnetic fields on bacteria Rhodospirillum rubrum VKM B-1621

Bacteria are the simplest model of living organisms and thus are a convenient object for magnetobiological research. This paper describes some effects of combined magnetic fields (CMFs) on the bacterium Rhodospirillum rubrum strain VKM B-1621, which is not a pathogen but was selected due to its wide spectrum of growth abilities. The authors chose magnetic field-resonant phosphorus and iron (Fe³⁺ ) because P-containing biochemical compounds (standard abbreviations PP₁ , AMP, ADP, ATP) provide energy flows in bacteria while iron could take part in formation of magnetosensitive intracellular inclusions. CMFs were produced by interaction of a geomagnetic field (В_DС ) and an alternating electromagnetic field (В_АС ), which were similar in their intensities. Their magnetic characteristics were as follows: (CMF-1) В_DC  = 46.80 µТ, В_АС  = 86.11 µT, f = 807.0 Hz; (CMF-2) В_DC  = 46.80 µТ, В_АС  = 86.11 µT, f = 38.3 Hz; that is, the frequencies of applied alternating electromagnetic fields coincided with cyclotron frequencies of phosphorus or ferric ions, respectively. The blank variants were exposed to the geomagnetic field. The CMFs increased bacterial consumption of dissolved iron as measured by residual concentrations of iron in the medium (P > 99%). An increase of bacterial nitrate reduction in the CMFs was statistically insignificant (P > 90%) when measured by residual concentrations of nitrate. Application of CMFs can influence bacterial activity and metabolism. Bioelectromagnetics. 2018;39:485-490, 2018. © 2018 Wiley Periodicals, Inc.