Resonant growth rate response of yeast cells irradiated by weak microwaves

The growth behaviour of yeast cultures in aqueous suspension was monitored by visible light extinction and showed an exponential growth rate reproducible within ±3% limits. When the cultures were irradiated by c.w. microwave fields of a few mW/cm2 the growth rate either stayed constant or was considerably enhanced or reduced depending on the frequency around 42 GHz. A spectral fine structure with a width of the order of 10 MHz was observed....