감마선 조사가 vibrio vulnificus의 Metalloprotease 유전자 발현에 미치는 영향

Effect of Gamma Irradiation on the Expression of Gene Endoding Metalloprotease in Vibrio vulnificus

  • 정진우 (한국원자력연구원 방사선생명공학연구센터) ;
  • 임상용 (한국원자력연구원 방사선생명공학연구센터) ;
  • 조민호 (한국원자력연구원 방사선생명공학연구센터) ;
  • 윤혜정 (한국원자력연구원 방사선생명공학연구센터) ;
  • 허정무 (한국원자력연구원 방사선생명공학연구센터) ;
  • 김동호 (한국원자력연구원 방사선생명공학연구센터)
  • Jung, Jin-Woo (Radiation Research Center for Biotechnology, Korea Atomic Energy Research Institute) ;
  • Lim, Sang-Yong (Radiation Research Center for Biotechnology, Korea Atomic Energy Research Institute) ;
  • Joe, Min-Ho (Radiation Research Center for Biotechnology, Korea Atomic Energy Research Institute) ;
  • Yun, Hye-Jeong (Radiation Research Center for Biotechnology, Korea Atomic Energy Research Institute) ;
  • Hur, Jung-Mu (Radiation Research Center for Biotechnology, Korea Atomic Energy Research Institute) ;
  • Kim, Dong-Ho (Radiation Research Center for Biotechnology, Korea Atomic Energy Research Institute)
  • 발행 : 2008.03.28

초록

방사선 조사 후에 생존한 병원성 미생물의 안정성을 연구하기 위하여 패혈증을 일으키는 Vibrio vulnificus ATCC 29307의 병원성 인자인 metalloprotease (vvp) 유전자의 발현과 효소 활성의 변화를 감마선 조사 후에 시간대별로 확인하였다. V. vulnificus는 다른 병원성 미생물들에 비하여 비교적 높은 방사선 감수성을 보였으며 방사선 조사 직후 유도기를 거친 후에 성장이 다시 시작되었다. 감마선을 조사하였을 경우 vvp 유전자의 발현은 비조사구에 비하여 $3{\sim}6$시간 정도 빨리 유도되었으나 총 metalloprotease의 활성은 감소하였다. 또한, vvp 유전자의 발현이 최대로 증가한 시점에서 metalloprotease의 활성을 비교한 결과 감마선이 조사된 균의 경우 감마선이 조사되지 않은 균에 비하여 약 $70{\sim}80%$ 수준으로 생산량이 감소하는 것을 알 수 있었다. 결론적으로, 감마선 조사 후 생존한 Vibrio vulnificus에서 병원성 인자 (vvp)의 발현 및 활성은 증가하지 않았으며 본 연구결과는 감마선 조사 식품의 미생물학적 안정성을 보여주는 기초 자료중의 하나로 활용될 수 있을 것으로 판단된다.

To check the microbiological safety with respect to increased virulence of surviving pathogens after irradiation, in this study, the transcriptional change of vvp gene encoding metalloprotease, which is one of the typical virulence factors of Vibrio mulnificus, was monitored by real-time PCR during the course of growth cycle after reinoculation of irradiated Vibrio. When V. vulnificus was exposed to a dose of 0.5 and 1 kGy, the lag period before growth resumption of sub-cultures became longer than non-irradiated counterpart as increase of irradiation dose. In the case of non-irradiated culture, the transcription of vvp was significantly activated at 15 h after inoculation, when bacterial growth reached the stationary phase, and the highest level of pretense activity (686 U/mL) was measured at the same time. Interestingly, vvp expression of irradiated Vibrio was turned up earlier than non-irradiated Vibrio during the mid log phase of growth, whereas these rapid induction of vvp expression from irradiated cells didn't result in an increase of metalloprotease production. When Vibrio was irradiated at 0.5 and 1 kGy, the protease activities peaked at 18 h after inoculation and the levels of activities were lower 1.2- and 1.4-fold, respectively, compared to the non-irradiated counterpart. Results from this study indicate that gamma radiation is not likely to activate the virulence ability of surviving Vibrio.

키워드

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