Study type: Medical/biological study (experimental study)

Using model organism Saccharomyces cerevisiae to evaluate the effects of ELF-MF and RF-EMF exposure on global gene expression med./bio.

By: Chen G, Lu D, Chiang H, Leszczynski D, Xu Z
Published in: Bioelectromagnetics 2012; 33 (7): 550-560
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Aim of study (acc. to author)

To study the effects of 50 Hz sinusoidal extremely low frequency magnetic field and GSM 1800 MHz radiofrequency electromagnetic field exposure on gene expression in the yeast Saccharomyces cerevisiae, and to identify and compare the EMF-responsive genes of these two frequencies.

Background/further details

Heat shock treatment served as positive control.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 6 h
Exposure 2: 1,800 MHz
Modulation type: pulsed
Exposure duration: intermittent, 5 min "on" - 10 min "off" for 6 h
  • SAR: 4.7 W/kg average over time (in the lowest 8 µm of the Petri dish bottom)

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 6 h
Exposure setup
Exposure source
Setup three groups of 36 cm x 36 cm square copper coils placed inside a CO2 incubator; upper, middle and lower coils connected in series and spaced 8 cm apart; coil system placed inside an iron container with ventilation holes; magnetic field uniform in a 10 cm x 10 cm x 10 cm area in the center of the coil system, where the 100 mm Petri dishes were placed
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT - measured - -

Exposure 2

Main characteristics
Frequency 1,800 MHz
Type
Exposure duration intermittent, 5 min "on" - 10 min "off" for 6 h
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Additional info

simulating GSM
Exposure setup
Exposure source
Setup waveguide placed inside a cell culture incubator; six 35 mm Petri dishes placed inside the waveguide at the H-field maximum of the standing wave
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 4.7 W/kg average over time calculated - in the lowest 8 µm of the Petri dish bottom

Reference articles

  • Zeng Q et al. (2006): Effects of global system for mobile communications 1800 MHz radiofrequency electromagnetic fields on gene and protein expression in MCF-7 cells
  • Schuderer J et al. (2004): High Peak SAR Exposure Unit With Tight Exposure and Environmental Control for In Vitro Experiments at 1800 MHz
  • Schönborn F et al. (2001): Basis for optimization of in vitro exposure apparatus for health hazard evaluations of mobile communications
  • Kuster N et al. (2000): Recommended minimal requirements and development guidelines for exposure setups of bio-experiments addressing the health risk concern of wireless communications
  • Li CM et al. (1999): Effects of 50 Hz magnetic fields on gap junctional intercellular communication

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Microarray-detected expression changes in three of the extremely low frequency magnetic field responsive candidate genes could not be confirmed using RT-PCR. On the other hand, out of the 40 potential radiofrequency electromagnetic field-responsive genes, only the expressions of two genes were confirmed by RT-PCR (structural maintenance of chromosomes 3 (SMC3) and aquaporin 2), while three other genes showed opposite changes in expression (downregulation) compared to the microarray data (upregulation).
In conclusion, the findings suggest that the yeast cells did not alter gene expression in response to the 50 Hz extremely low frequency magnetic field and that the response to the radiofrequency electromagnetic field is limited to only a very small number of genes. Further studies are needed to address whether the observed changes in gene expression might have any impact on Saccharomyces cerevisiae physiology.

Study character:

Study funded by

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