Nonthermal effects of millimeter microwaves on yeast growth.

Weak microwave irradiation of aqueous yeast cultures was found to affect their growth rate in a frequency-selective manner. Depending on frequency (near 42 GHz), both increases and decreases of the growth rate were observed. The resonance bandwidths are of the order of 0.01 GHz. Simple thermal effects can be excluded. These findings support theoretical predictions of coherent molecular oscillations activating metabolic processes.