Proliferation response of yeast Saccharomyces cerevisiae on electromagnetic field parameters

Former results on electrostimulation of proliferation of yeast suspensions by weak alternating fields (50 Hz) in the amplitude region 0.2-12 mT, produced by a pair of Helmholtz coils, have been extended to frequencies between 10 and 100 Hz, using an amplitude of 0.5 mT. At 50 Hz the proliferation yield increases of more than 25 +/- 5% are in agreement with the former measurements. An additional 'electric window' of similar height was detected at 15 Hz besides a minimum at 40 Hz. Preliminary data show that the temperature dependence of both windows have marked differences. The stimulating effect can also be followed by the ATP content of cells, whereas the glucose consumption differences are not significant. Our results evidence that it will be imperative to measure broad ranges of at least four physical parameters: amplitude, frequency, treatment time and temperature, besides defined biological conditions in order to avoid discrepancies between laboratories in future. (C) 1997 Elsevier Science S.A.