研究のタイプ: 医学/生物学の研究 (experimental study)

[大腸菌DNA研究用として最適な900 MHzラジオ波の最適な平面伝送線路] med./bio.

A suitable plane transmission line at 900 MHz rf fields for E. coli DNA studies.

掲載誌: Rev Sci Instrum 2005; 76 (5): k.A

The detailed summary of this article is not available in your language or incomplete. Would you like to see a complete translation of the summary? Then please contact us →

研究目的(著者による)

The aim of this study was to develop a microbial assay system for easy testing possible effects of the exposure to 900 MHz radiofrequency electromagnetic fields on genome stability of different Escherichia coli strains proficient or defective in methyl-directed mismatch repair system.

詳細情報

In Escherichia coli the methyl-directed mismatch repair system plays an important role in correction of errors made during DNA replication and genetic recombination.
Different Escherichia coli strains were used transformed with an erythromycin (antibiotics)-resistance plasmid (allowing determination of mutation frequencies).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 900 MHz
ばく露時間: continuous for 3 hr, 6 hr, 12 hr or 24 hr

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 3 hr, 6 hr, 12 hr or 24 hr
ばく露装置
ばく露の発生源/構造
  • signal generator
ばく露装置の詳細 cells placed inside the planar transmission line between the electrodes; line width = 10 cm, line length = 40 cm, distance between electodes = 1.5 cm; two BNC connectors mounted on the longitudinal ends of the line; B- and E-field direction in a plane perpendicular to the propagation direction of the wave
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電界強度 66 V/m maximum 測定値 - -
電界強度 40 V/m minimum 測定値 - -
磁束密度 156 nT minimum 計算値 - -
磁束密度 260 nT maximum 計算値 - -
SAR 0.22 mW/kg mean 推定値 - at E = 1.1 V/m d: bei
SAR 24 µW/kg mean 推定値 - at E = 0.37 V/m d: bei
SAR 2.7 µW/kg mean 推定値 - at E = 0.12 V/m d: bei
SAR 0.3 µW/kg mean 推定値 - at E = 0.04 V/m d: bei

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
調査の時期:
  • ばく露後

研究の主なアウトカム(著者による)

Using the present reporter gene system, a slight anti-mutagenic effect of the radiofrequency exposure was demonstrated. An effect was only found in the mismatch repair-proficient strain. Precisely, in the proficient strain, exposure for 24 h to radiofrequency electromagnetic fields (at a SAR value of 2.2 x 10-4 W/kg) decreased the mutation frequencies to erythromycin resistance of about 2.8 fold in comparison to the sham exposed cells. The anti-mutagenic effect of radiofrequency exposure increased with the exposure time (peaking in 12 and 24 h exposed cells). The effect was also observed at a SAR value of 2.4 x 10-5 W/ kg, whereas it was not detectable at SAR values of 2.7 x 10-6 or 3.0 x 10-7 W/kg, demonstrating the existence of dose-response relationship.
In contrast, in mismatch repair-defective strains, the mutation frequency was unaffected by radiofrequency electromagnetic field exposure.
The data indicate that the anti-mutagenic effect of the 900 MHz radiofrequency exposure might be due to an improved efficiency of the mismatch repair system. The mechanism by which the radiofrequency electromagnetic field may affect the activity of the mismatch repair system is unclear.

研究の種別:

研究助成

関連論文