Cell density dependent response of E. coli cells to weak ELF magnetic fields

Area of Science:

• Biophysics
• Cell Biology
• Electromagnetism

Background:

• Extremely low frequency (ELF) electromagnetic fields are ubiquitous.
• Understanding cellular responses to ELF fields is crucial for biological and medical applications.
• Previous studies have shown varied effects of ELF fields on biological systems.

Purpose of the Study:

• To investigate the effects of weak ELF magnetic fields on E. coli K12 AB1157 cells.
• To determine the influence of cell density on the cellular response to ELF exposure.
• To elucidate the underlying mechanisms of ELF field effects on bacterial cells.

Main Methods:

• Utilized the anomalous viscosity time dependencies (AVTD) method to assess cellular changes.
• Exposed E. coli cells at various densities (5 x 10(5)-10(9) cell/ml) to a 9 Hz, 30 microT ELF sinusoidal field for 15 minutes.
• Analyzed the kinetics of per-cell-normalized ELF effects, fitting them to a Gaussian distribution.

Main Results:

• Observed a transient effect on cell viscosity, peaking 40-120 minutes post-exposure.
• Cell density significantly influenced the magnitude and timing of the ELF effect, with distinct plateau regions and transitions.
• The maximum effect occurred at a cell density of 4 x 10(8) cell/ml, with minimal effect at the lowest density.
• Evidence suggests a secondary reaction mechanism, possibly involving unstable compounds like radicals, rather than direct primary effects or stable chemical messengers.

Conclusions:

• Cell-to-cell interactions play a key role in the response of E. coli to ELF magnetic fields.
• The observed effects are likely mediated by secondary reactions, potentially involving radical species.
• The findings are consistent with models involving re-emission of secondary photons during resonance fluorescence.