Medical/biological study (experimental study)

ELF electromagnetic fields increase hydrogen peroxide (H2O2)-induced mutations in pTN89 plasmids med./bio.

By: Koyama S, Nakahara T, Hirose H, Ding GR, Takashima Y, Isozumi Y, Miyakoshi J

Published in: Mutat Res Genet Toxicol Environ Mutagen 2004; 560 (1): 27-32

Aim of study (acc. to author)

This in vitro study was performed to compare the mutagenic effects of hydrogen peroxide (H₂O₂) in the presence and absence of an extremely low frequency magnetic field.

Background/further details

To estimate the mutagenic effect pTN89 plasmids were used. Mutations were detected in the supF gene carried by these plasmids in E. coli. This system can find out a mutation at the single base level in the supF gene. The plasmid DNAs were treated with/without extremley low frequency electromagnetic field and than transformed in E. coli. The E. coli strain used is resitant to specific antibiotics if it contains a mutant supF gene forming white colonies on culture medium containing this antibiotics, whereas cells carrying an active supF gene do not produce colonies on such culture media.

Endpoint

genotoxicity/mutation: gene mutations

Exposure

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 4 h	magnetic flux density: 5 mT unspecified

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Exposure duration	continuous for 4 h

Exposure setup

Exposure source	Helmholtz coils
Chamber	CO2 incubator with a built in coils system kept at 37°C. The inside and outside of the incubators were shielded by silicon steel and Permally C respectively.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	5 mT	unspecified	unspecified	-	-

Exposed system:

plasmid

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: supF gene mutations (number of transformants occure as white colonies), supF gene sequencing (PCR)

Investigated system:

DNA/RNA
bacterium

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The exposure to extremely low frequency electromagnetic field alone did not show any mutation. The mutation frequency for plasmids treated with H₂O₂ and electromagnetic field was about 2.5-fold higher than that for treatment with H₂O₂ alone.
This indicates that the extremely low frequency electromagnetic field may potentiate H₂O₂-induced mutation.
The sequence analysis of the supF mutant plasmids revealed no difference in the mutation spectrum between the groups.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Research for Future Program, Japan Society for the Promotion of Science (JSPS), Japan

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