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

[<i>E.coli</i>の生存能力及び代謝活性に対する99 GHzミリ波の連続波放射の影響] med./bio.

Effect of 99 GHz continuous millimeter wave electro-magnetic radiation on E. coli viability and metabolic activity.

掲載誌: Int J Radiat Biol 2010; 86 (5): 390-399

この研究は、大腸菌(E.coli)の生存能力及び代謝活性に対する99 GHzミリ波連続波(CW)放射の影響におけるばく露時間依存性を調べた。光学密度OD660nm=0.1のE. coli懸濁液生存能力検査に、OD660nm=1.0のものを代謝活性検査に用いた。後進波発信管(BWO)からホーンアンテナにより放射させた99 GHzのCW電磁界は、E. coli液面で0.2 mW/cm2のほぼ理想的なガウスビームであった。その結果、ばく露1時間ではE.coliの生存能力及びコロニー特性に影響はなかった;ばく露19時間では、ユニットを形成するコロニー数が、擬似ばく露群及び対照群に比べばく露群では約2倍高くなったが、E. coliの代謝活性への影響はなかった、などの所見を報告している。

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研究目的(著者による)

To study the dependence of exposure duration (1 h or 19 h) of continuous wave millimeter wave 99 GHz irradiation on Escherichia coli bacterial cell viability and metabolic activity.

詳細情報

All experiments were performed on Escherichia coli populations during the logarithmic phase. For cell viability tests two exposure methods were used: 1) exposure was conducted on cells that were spread on agar plates, and 2) exposure was conducted on cells that were suspended in two different culture mediums (PBS (to study the cell death) or LB (to study cell division)). For metabolic activity test exposure (19 h) was conducetd on cells that were suspended in LB medium.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 99 GHz
Modulation type: CW
ばく露時間: continuous for 1 h
ばく露2: 99 GHz
Modulation type: CW
ばく露時間: continuous 1 h or 19 hr

ばく露1

主たる特性
周波数 99 GHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 1 h
Modulation
Modulation type CW
ばく露装置
ばく露の発生源/構造
Distance between exposed object and exposure source 22 mm
ばく露装置の詳細 agar plate at a short distance from the antenna
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力密度 0.17 mW/cm² - 計算値 - at the bacterial plane

ばく露2

主たる特性
周波数 99 GHz
タイプ
  • electromagnetic field
ばく露時間 continuous 1 h or 19 hr
Modulation
Modulation type CW
ばく露装置
ばく露の発生源/構造
Distance between exposed object and exposure source 0.5 cm
ばく露装置の詳細 bacterial suspensions placed above the antenna
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
電力密度 0.2 mW/cm² - 計算値 - at the bacterial plane

Reference articles

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)

The data showed that 1 hour of exposure to 99 GHz continuous wave electromagnetic field irradiation had no effect on Escherichia coli viability and colony characterisation. In 19 h of exposure, the number of colony forming units was half order of magnitude higher than the sham exposed and the control: In exposed samples, the calculated viable cells in PBS and LB medium were 8.19 x 107 and 1.47 x 109 cells/ml, respectively. In the sham exposed samples, the calculated viable cells in PBS and LB medium were 3.47 x 107 and 8.41 x 108 cells/ml, respectively. However, 19 h of exposure did not affect the metabolic activity.
The authors conclude that exposure of Escherichia coli to millimeter wave 99 GHz irradiation (continuous wave) for a short period did not affect the viability of Escherichia coli bacterial cells. However, exposure for 19 h caused a slight proliferation but did not influence the metabolic activities (of about 90 biochemical reactions that were examined). Hence, the authors assume that the slight proliferation (half order of magnitude) after 19 h of exposure does not have a biological meaning.

研究の種別:

研究助成

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