一酸化窒素による腸管出血性大腸菌O157の抗菌メカニズムとベロトキシン産出量 (平成14年度麻布大学公的研究助成金事業研究成果報告)  [in Japanese] Antimicrobial mechanism of nitric oxide for verotoxigenic Escherichia coli O157 : H7 and the amount of verotoxins  [in Japanese]

Access this Article

Author(s)

Abstract

亜硝酸ナトリウム(NaNO_2),塩化ナトリウム(NaCI)あるいは数種類の抗生物質で処理したベロトキシン産生大腸菌(VTEC)O157:H7の3株から,ベロトキシン(VT)1型と2型の放出量を定量した。VTEC O157:H7のうち,2株がVT1型とVT2型の両者を産出し,1株がVT2型のみ産出した。VTEC O157:H7をNaNO_2(最少発育阻止濃度である6,000mg/L)で処理したがVT1型およびVT2型の放出量は増加しなかった。NaNO_2由来の一酸化窒素(NO)の抗菌メカニズムを明らかにするために,NaNO_2で処理したVTEC O157:H7の細胞を77Kでの電子常磁性共鳴吸収(EPR)法に供した。その結果,g値2.035と2.010のEPRシグナルを検出し,細胞内に鉄硫黄タンパク質とNOが反応して形成されたジニトロシル鉄硫黄錯体が存在した。またATPの合成も阻害されていた。このことから,NaNO_2出来のNOは細胞内に入り,呼吸鎖に関与する酵素を不活化したものと考えられた。

The levels of verotoxin-1 and verotoxin-2 released from verotoxigenic Escherichia coli O157:H7 treated in vitro with sodium nitrite, sodium chloride and several antibiotics were estimated. Of the three strains of E. coli O157:H7 used in this study, two strains produced both verotoxin-1 and verotoxin-2 and one strain produced only verotoxin-2. Treatment of E. coli O157:H7 with sodium nitrite (6,000 mg/L, a minimum inhibitory concentration) did not increase the levels of verotoxin-1 and verotoxin-2 compared with treatment by sodium chloride or antibiotics. When the electron paramanetic resonance spectrum of sodium nitrite-treated bacterial cells was examined at 77K to clarify the mechanism of the anti-bacterial activity of nitric oxide derived from sodium nitrite, electron paramagnetic resonance signals with g-values of 2.035 and 2.010 were observed. These were identified as being derived from iron-nitric oxide complexes. It appeared that the dinitrosyl iron complexes in the E. coli O157:H7 cells were generated through reaction of iron-sulfur proteins (enzymes) with nitric oxide formed by the reduction of sodium nitrite. These findings indicate that nitric oxide derived from sodium nitrite penetrates the cells and inactivates enzymes related to the respiratory chain.

Journal

  • Journal of Azabu University

    Journal of Azabu University 5・6, 176-181, 2002

    Azabu University

Codes

  • NII Article ID (NAID)
    110004323697
  • NII NACSIS-CAT ID (NCID)
    AA11561468
  • Text Lang
    JPN
  • Article Type
    特集
  • Journal Type
    大学紀要
  • ISSN
    13465880
  • NDL Article ID
    7067041
  • NDL Source Classification
    ZM2(科学技術--科学技術一般--大学・研究所・学会紀要)
  • NDL Call No.
    Z74-C608
  • Data Source
    NDL  NII-ELS  IR 
Page Top