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

[Bacillus subtilisの成長に及ぼす新開発超伝導磁石システムによる高磁界の影響] med./bio.

Effect of high magnetic field on the growth of Bacillus subtilis measured in a newly developed superconducting magnet biosystem

著者: Nakamura K, Okuno K, Ano T, Shoda M
掲載誌: Bioelectrochem Bioenerg 1997; 43 (1): 123-128
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生物学的反応を温度制御下で実施可能な0.5-7T発生超伝導マグネットシステムを開発した。好気性バクテリアを振とう培養し、その際の均一磁界（7T）および勾配磁界（5.2-6.1T）に設置場合の影響を細胞数の違いにより調べたところ、定常期において勾配磁界曝露した細胞の数は地磁気群よりも約2倍多く、高磁界により細胞数減少が阻止されていることがわかった。勾配磁界下の細胞の減少は細胞死によるものであった。勾配磁界曝露下では、生細胞における胞子形成の阻害が観察され、特に曝露12時間ではアルカリフォスファターゼ活性が抑制されていた。形質転換させたバクテリアを勾配磁界に曝露したところ、定常期において細胞数の減少を阻止し、なおかつリポペプチド抗生物質、界面活性剤の濃縮物を多く産生した。

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研究目的（著者による）

To investigate the effects of inhomogeneous (5.2-6.1 T) and homogeneous (7 T) high magnetic fields on the aerobic growth and spore formation of the bacterium Bacillus subtilis.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1:
  • DC/static
ばく露時間: continuous for 12, 18, 24, 30, 36, 48 and 72 h
homogeneous magnetic field
  • 磁束密度: 7 T (at the center of the bore of the magnet)
ばく露2:
  • DC/static
ばく露時間: continuous for 12, 18, 24, 30, 36, 48 and 72 h
inhomogeneous magnetic field

ばく露1

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 continuous for 12, 18, 24, 30, 36, 48 and 72 h
Additional information homogeneous magnetic field
Additional information Homogeneous magnetic field exposure Reference article: K.Ouda, K.Saito, T.Kamikado, S.Ito, K.Matsumoto, K.Okuno, K.Tsuhiya, T.Ano and M.Shoda. New 7 T superconducting magnet system for bacterial cultivation, Cryogenics, 35 (1995) 41-47.
ばく露装置
ばく露の発生源／構造
  • コイル
  • superconducting magnet with16 cm diameter bore in horizontal direction
ばく露装置の詳細 10 ml suspension was placed into two conical flasks and positioned in the magnet and the reference.
Additional information An incubator as a reference was covered with a magnetic shield, a double-walled cylindrical shell of Permalloy, in which the stay field was reduced to below the level of geomagnetic field strength. A ±0.5% deviation of the field homogeneity was observed in an area of 16 cm in diameter and 20 cm in length in the bore. This area was the homogeneous region, outside that region, a gradient with a slope of 23 T/m was formed.
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 7 T - 測定値 - at the center of the bore of the magnet
測定および計算の詳細

The magnetic field was measured by a flux meter.

ばく露2

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 continuous for 12, 18, 24, 30, 36, 48 and 72 h
Additional information inhomogeneous magnetic field
Additional information Inhomogeneous magnetic field
ばく露装置
ばく露の発生源／構造
  • E1と同じ装置
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 5.2 T - 測定値 - to 6.1 T

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）

No clear difference in cell number was observed between the homogeneous magnetic field exposure and the reference. The cell number under inhomogeneous magnetic field conditions was about twofold higher than that in the reference after 72 h. The results further suggests that the inhomogeneous magnetic field inhibits spore formation. The activity of alkaline phosphatase was significantly suppressed under inhomogeneous magnetic field conditions. Protease activity was also reduced, but not in the degree the alkaline phosphatase was. Under inhomogeneous magnetic field conditions the cell number of recombinant bacteria was larger than the reference, which was reflected in an enhanced production of the antibiotic surfactin. This leads to the suggestion that the magnetic field does not affect the stability of the plasmid.

研究の種別:

研究助成