Study type: Medical/biological study (experimental study)

Microwave-specific heating affects gene expression med./bio.

By: Saffer JD, Profenno LA
Published in: Bioelectromagnetics 1992; 13 (1): 75-78
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Aim of study (acc. to author)

To examine the effects of low-level microwave irradiation on gene expression in Escherichia coli in a sensitive model.

Background/further details

The model is E. coli with a plasmid that provides the marker gene β-galactosidase.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.55 GHz
Exposure duration: 4.5 h
  • SAR: 9.4 mW/g
Exposure 2: 2.55 GHz
Exposure duration: 4.5 h
  • SAR: 10.7 mW/g
Exposure 3: 2.55 GHz
Exposure duration: 4.5 h
  • SAR: 9.8 mW/g
Exposure 4: 2.55 GHz
Exposure duration: 4.5 h
  • SAR: 10.1 mW/g
Exposure 5: 2–4 GHz
Exposure duration: 4.5 h

Exposure 1

Main characteristics
Frequency 2.55 GHz
Type
Exposure duration 4.5 h
Modulation
Modulation type unspecified
Exposure setup
Exposure source
Setup Culture tubes placed into individual antenna which were submerged in transformer oil.
Additional info Cultures placed in in sterile 2 ml screw top cultures containing a 7 mm magnetic stirring bar.
Parameters
Measurand Value Type Method Mass Remarks
SAR 9.4 mW/g - - - -

Exposure 2

Main characteristics
Frequency 2.55 GHz
Type
Exposure duration 4.5 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 10.7 mW/g - - - -

Exposure 3

Main characteristics
Frequency 2.55 GHz
Type
Exposure duration 4.5 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 9.8 mW/g - - - -

Exposure 4

Main characteristics
Frequency 2.55 GHz
Type
Exposure duration 4.5 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 10.1 mW/g - - - -

Exposure 5

Main characteristics
Frequency 2–4 GHz
Type
Exposure duration 4.5 h
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 10 mW/g - - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The existence of an increase in β-galactosidase expression by microwave irradiation was confirmed,- an increase not duplicated by bulk heating. The effect appeared to be due to heating effects peculiar to microwaves.
No significant differences in cell density were observed between irradiated and sham-irradiated cultures at the end of the exposure period. The results indicate that small thermal gradients may be a source of biological effects of non-ionizing radiation.

Study character:

Study funded by