Investigation of the Effects of 2.45 GHz Near-Field EMF on Yeast

Abstract

The study of the effects of 2.45 GHz electromagnetic fields on the health and safety of people and organisms as a whole is essential due to their widespread use in everyday life. It is known that they can cause thermal and non-thermal effects-at the molecular, cellular and organismal level. Yeast suspensions were treated with 2.45 GHz microwave radiation in the near-field of antenna at two distances (2 and 4 cm) and two time periods (20 and 60 min)-setups resembling the use of mobile devices. The release of UV-absorbing substances from the cells was studied as an indicator of membrane permeabilization, total intracellular antioxidant activity and reduced glutathione were determined, and a comet assay for damage to the DNA was performed. A correlation between reduced antioxidants and increased membrane permeability during EMF treatment was observed at a distance of 2 cm for 20 min, suggesting the presence of oxidative stress, while a similar effect was not observed with conventional heating. Slightly increased membrane permeability was observed after irradiation for 60 min at a distance of 4 cm, but this was not related to the antioxidant status of the cells. A trend towards increased DNA damage was observed under both conditions.

Keywords: RF-EMF; Saccharomyces cerevisiae; antioxidant capacity; cell membrane permeability; comet assay; electromagnetic pollution; glutathione; heating; microwaves; non-thermal effects.

Figure 1

(A) The 2.45 GHz EMF exposure setup of the samples in the semi-anechoic chamber. The top of the dipole antenna is visible in the middle of the Styrofoam box where the samples are placed 2 cm (tubes labeled as “1” and “2”) and 4 cm away from the antenna (tubes “4” and “5”). EMF-dissipative cones are also visible. (B) Thermogram of a sample obtained by an infrared camera used to monitor temperature change during the treatment period both for irradiated and control samples. False color temperature scale where white corresponds to the highest and black to the lowest temperature, in an arbitrarily defined range. Values for different markers are displayed. Temperatures at the bottom of the tubes where the suspension is located were used for analyses.

Figure 2

Absorbance at 260 nm (A₂₆₀) determined by the nucleic acids leaked from yeast cells: irradiated with a 2.45 GHz microwave in three exposure conditions, 2 cm away from the antenna for 20 min, 4 cm for 20 min and 4 cm for 60 min (EMF), undergoing corresponding conventional heating (heating), not irradiated (control) or held at room temperature (RT) for the same periods of time. The values presented are mean ± SEM, and distinct letters denote significantly different variants among each experimental setup (p < 0.05).

Figure 3

Reduced glutathione (GSH, mg/mL) content in yeast cells: irradiated with a 2.45 GHz microwave in three exposure conditions, 2 cm away from the antenna for 20 min, 4 cm for 20 min and 4 cm for 60 min (EMF), undergoing corresponding conventional heating (heating), not irradiated (control) or held at room temperature (RT) for the same periods of time. The values presented are mean ± SEM, and distinct letters denote significantly different variants among each experimental setup (p < 0.05).

Figure 4

Antioxidant capacity, expressed as Trolox equivalent (mmol/L), of yeast cells: irradiated with a 2.45 GHz microwave in three exposure conditions, 2 cm away from the antenna for 20 min, 4 cm for 20 min and 4 cm for 60 min (EMF), undergoing corresponding conventional heating (heating), not irradiated (control) or held at room temperature (RT) for the same periods of time. The values presented are mean ± SEM, and distinct letters denote significantly different variants among each experimental setup (p < 0.05).

Figure 5

Comet tail length (pixels) determined by single-cell gel electrophoresis of yeast cells irradiated with a 2.45 GHz microwave in three exposure conditions, 2 cm away from the antenna for 20 min, 4 cm for 20 min and 4 cm for 60 min (EMF), or not irradiated (control). The values presented are mean ± SEM, and distinct letters denote significantly different variants among each experimental setup (p < 0.05).

Figure 6

Comet tail DNA percentage determined by single-cell gel electrophoresis of yeast cells irradiated with a 2.45 GHz microwave at three exposure conditions, 2 cm away from the antenna for 20 min, 4 cm for 20 min and 4 cm for 60 min (EMF), or not irradiated (control). The values presented are mean ± SEM, and distinct letters denote significantly different variants among each experimental setup (p < 0.05).

Figure 7

Comet olive tail moment (arb. u.) determined by single-cell gel electrophoresis of yeast cells irradiated with a 2.45 GHz microwave at three exposure conditions, 2 cm away from the antenna for 20 min, 4 cm for 20 min and 4 cm for 60 min (EMF), or not irradiated (control). The values presented are mean ± SEM, and distinct letters denote significantly different variants among each experimental setup (p < 0.05).