Magnetic field exposure enhances mRNA expression of sigma 32 in E. coli.

The mechanism of interaction between weak electromagnetic fields and cells is not understood. As a result, the health effect(s) induced by exposure to these fields remains unclear. In addition to questions relating to the site of initial magnetic field (MF) interactions, the nature of the cell's response to these perturbations is also unclear. We examined the hypothesis that the cells respond to MFs in a manner similar to other environmental stressors such as heat. Using the bacterium Escherichia coli, we examined the mRNA levels of sigma 32, a protein that interacts with RNA polymerase to help it recognize a variety of stress promoters in the cell. Our data show that the intracellular level of sigma 32 mRNA is enhanced following a 15-min exposure to a 60 Hz, 1.1 mT magnetic field.