Scrutinizing microwave effects on glucose uptake in yeast cells.

Taking into account different literature reports on microwave (MW) effects on living organisms, we thoroughly investigated the influence of constant 2.45 GHz MW irradiation on glucose uptake in yeast cells. A Saccharomyces cerevisiae suspension of 2.9 × 108 cells/ml was used in all experiments. A large specific absorption rate of 0.55 W/g of suspension is compensated by efficient external cooling of the reaction vessel, which established a strong non-equilibrium flow of energy through the solution and enabled a constant bulk temperature of 30 °C to within 1 °C during glucose uptake. Comparison of MW effects with control experiments revealed insignificant changes of glucose uptake during the initial stages of the experiment (up to the 10th min). Statistically "notable" differences during the next 20 min of the irradiation were detected corresponding to thermal overheating of 2 °C. Possible specific thermal MW effects may be related to local temperature increase and a large flow of energy throughout the system. The obtained effects show that environmental MW pollution (fortunately) is of too low intensity to provoke metabolic changes in living cells. At the same time, a longer exposure of cells to electromagnetic irradiation may have impacts on biochemical applications and production of valuable biotechnological products.