EXTREMELY HIGH-FREQUENCY ELECTROMAGNETIC-FIELDS AT LOW-POWER DENSITY DO NOT AFFECT THE DIVISION OF EXPONENTIAL PHASE SACCHAROMYCES-CEREVISIAE CELLS

Exponentially growing cells of the yeast Saccharomyces cerevisiae were exposed to electromagnetic fields in the frequency range from 41.682 GHz to 41.710 GHz in 2 MHz increments at low power densities (0.5 mu W /cm(2) and 50 mu W/cm(2)) to observe possible nonthermal effects on th e division of this microorganism The electronic setup was carefully de signed and tested to allow precise determination and stability of the electromagnetic field parameters as well as to minimize possible effec ts of external sources. Two identical test chambers were constructed i n one exposure system to perform concurrent control and test experimen ts at every frequency step under well-controlled exposure conditions. Division of cells was assessed via time-lapse photography. Control exp eriments showed that the cells were dividing at submaximal rates, ensu ring the possibility of observing either an increase or a decrease of the division rate. The data from several independent series of exposur e experiments and from control experiments show no consistently signif icant differences between exposed and unexposed cells. This is in cont rast to previous studies claiming nonthermal effects of electromagneti c fields in this frequency range on the division of S. cerevisiae cell s. possible reasons for this difference are discussed. (C) 1997 Wiley- Liss, Inc.