병원성 살모넬라의 활성산소종과 활성질소종에 대한 내성에서 글루타치온 합성효소의 역할

방일수 대한구강악안면병리학회 2008 대한구강악안면병리학회지 Vol.32 No.1

Intracellular pathogens must maintain redox homeostasis against the antimicrobial actions of reactive oxygen and nitrogen species produced by host cells. This study proves that glutathione is required to promote survival of an enteric pathogen Salmonella under the conditions producing reactive oxygen or nitrogen species. Glutathione is the non-protein thiol compound distributed in a variety of organisms and possesses strong electron-donating capability to reduce intracellular redox environment. To examine the role of glutathione on Salmonella redox homeostasis under oxidative and nitrosative stress conditions, gshB gene encoding glutathione synthetase was mutated by the one-step PCR inactivation method. The growth of gshB mutant Salmonella producing virtually no glutathione was greatly impaired in the culture media containing either hydrogen peroxide or nitric oxide donors. The results suggest that physiological levels of glutathione can provide a fundamental capability to maintain redox homeostasis for Salmonella in surviving oxidizing conditions of host cells.

살모넬라의 세포질외부-기능 시그마 인자 σE 발현에 미치는 철이온 농도의 영향

방일수 대한구강악안면병리학회 2008 대한구강악안면병리학회지 Vol.32 No.2

Biological organisms require iron for optimal metabolism. Intracellular pathogens also must secure iron especially during infection of animal hosts expressing NRAMP(natural resistance-associated macrophage protein), a transporter protein sequestering metal ions from pathogens. This study shows that extracytoplasmic function sigma factor σE is required for Salmonella virulence in NRAMP1-expressing mice, and further shows that iron deprivation turns on σE expression of Salmonella. The virulence of σE -deficient Salmonella is completely attenuated in C3H/HeN mice while wild type Salmonella kills all mice. Addition of an iron-chelator DTPA(Diethylene triamine pentaacetic acid) to culture media induces σE expression of Salmonella, but iron supplementation abrogates this induction. These findings suggest that iron limitation in host macrophages can trigger σE -dependent virulence system of Salmonella that may include bacterial iron homeostasis.

Salmonella Typhimurium 의 pH 조절 유전자에 관한 연구

방일수,유경만,엄준호,방성호,이영록,박용근 한국미생물생명공학회 1993 한국미생물생명공학회 학술발표초록집 Vol.1993 No.1

Salmonella Enteritidis와 Salmonella Gallinarum의 세균막스트레스를 인식하는 spy-gfp 오페론 융합체

강보경,방일수 한국낙농식품응용생물학회 2018 Journal of Dairy Science and Biotechnology (JMSB) Vol.36 No.4

Emergence of drug resistant strains of Salmonella enterica threatens milk processing and related dairy industries, thereby increasing the need for development of new anti-bacterials. Developments of antibacterial drugs are largely aimed to target the bacterial envelope, but screening their efficacy on bacterial envelope is laborious. This study presents a potential biosensor for envelope-specific stress in which a gfp reporter gene fused to spy gene encoding a periplasmic chaperone protein Spy (spheroplast protein y) that can sense envelope stress signals transduced by two major two-component signal transduction systems BaeSR and CpxAR in Salmonella enterica serovars Enteritidis and S. Gallinarum. Using spy-gfp operon fusions in S. Enterititis and S. Gallinarum, we found that spy transcription in both serovars was greatly induced when Salmonella cells were forming the spheroplast and were treated with ethanol or a membrane-disrupting antibiotic polymyxin B. These envelope stress-specific inductions of spy transcription were abrogated in mutant Salmonella lacking either BaeR or CpxR. Results illustrate that induction of Spy expression can be efficiently triggered by two-component signal transduction systems sensing envelope stress conditions, and thereby suggest that monitoring the spy transcription by spy-gfp operon fusions would be helpful to determine if developing antimicrobials can damage envelopes of S. Enteritidis and S. Gallinarum.

Salmonella typhimurium 에서 무산소 환경 유도유전자들에 대한 조절유전자들의 특성 및 클로닝

이윤정,방일수,이인수,이영록,박용근 ( Yun Joung Lee,Iel Soo Bang,In Soo Lee,Yung Nok Lee,Yong Keun Park ) 한국환경생물학회 1993 환경생물 : 환경생물학회지 Vol.11 No.2

New regulatory loci which participate in the anaerobic environment inducible gene(ani) expression in Salmonella typhimurium were identified. These regulators (oxr) showed negative regulatory effect on the anaerobiosis inducible operon fusions of this organism in aerobic environment (oxr 107 and oxr 108 to ani 2001, oxr 109 to ani 2007). They were identified as the trans-acting regulators, and increased β-galactosidase activity of ani-lacZ fusion strains up to about 10-240 fold in aerobic environment. By using the library of S. typhimurium chromosomal DNA, two negative regulators (oxr 101 and oxr 109) were cloned. The insert fragment of each clone, pPK32 for oxr 101 and pPK33 to oxr 109 were 7.8Kb and 9.3Kb, respectively. The recombinant plasmid pPK32 didn`t complement the mutation effect of oxr 101 on minimal media but rich media, pPK33 complemented the mutation effect of oxr 109 on both minimal and rich media.

Response Regulator RssB의 활성 조절

박희정,방일수,Park, Hee Jeong,Bang, Iel Soo 한국미생물학회 2013 미생물학회지 Vol.49 No.3

많은 세균들은 환경적 스트레스에 대항하기 위해 세균 생존에 유용한 특정 유전자들의 전사를 유도하는 대체시그마 인자 RpoS를 활용한다. 세포 내 RpoS 단백질의 농도는 주로 ClpXP 단백질 분해효소의 조절을 통해 결정된다. RpoS를 ClpXP로 전달하기 위해서는 adaptor 단백질 RssB가 반드시 필요하다. Two-component-type response regulator RssB는 RpoS와 지속적으로 상호작용을 하지만, 다양한 환경변화에 의해 RssB-RpoS 상호작용이 억제되어 세균에서 RpoS 양을 증가시킨다. 본 총설에서는 최근까지 연구 된 RssB-RpoS 상호작용에 관여하는 RssB의 anti-adaptor 단백질 IraD, IraM, IraP 등의 조절인자들과 RssB의 N-terminal 수용체 도메인의 인산화에 대해 설명하고 요약하였다. 이러한 RssB의 정교한 활성을 통한 RpoS 분해조절 과정은 외부환경 스트레스로부터 보다 효율적으로 세균을 보호할 수 있다. Against environmental stresses, many bacteria utilize the alternate sigma factor RpoS that induces transcription of the specific set of genes helpful in promoting bacterial survival. Intracellular levels of RpoS are determined mainly by its turnover through proteolysis of ClpXP protease. Delivery of RpoS to ClpXP strictly requires the adaptor protein RssB. The two-component-type response regulator RssB constantly interacts with RpoS, but diverse environmental changes inhibit this interaction through modification of RssB activity, which increases RpoS levels in bacteria. This review discusses and summarizes recent findings on regulatory factors in RssB-RpoS interactions, including IraD, IraM, IraP anti-adaptor proteins of RssB and phosphorylation of N-terminal receiver domain of RssB. New information shows that the coordinated regulation of RssB activity in controlling RpoS turnover confers efficient bacterial defense against stresses.

세균의 인산 항상성: 인산 수송 단백질들의 역할

박윤미,방일수,Park, Yoon-Mee,Bang, Iel-Soo 한국미생물학회 2012 미생물학회지 Vol.48 No.2

인은 인지질, 탄수화물 및 핵산 등의 생분자 합성에 필요한 원소이다. 세균은 외부환경으로부터 인산이나 인산을 포함하는 영양소를 흡수하여 인을 얻고, 세포대사에 사용되고 남은 인산은 polyphosphate 형태로 저장한다. 현재까지 알려진 다섯 개의 인산 수송 시스템 중, 인산에 특이적으로 높은 친화력을 갖는 Pst 시스템이 가장 중요한 역할을 하며, 그 발현은 세포외부 인산 농도에 반응하는 PhoB-PhoR two component 신호전달 시스템에 의해 조절된다. 반응 조절 단백질 PhoB는 인산 대사뿐 아니라 이와 관계없는 유전자들의 전사를 조절하는 것으로 알려졌으며, 따라서 PhoB의 활성이 조절되지 않으면 많은 종류의 다른 표현형이 나타난다. 본 총설은 각 인산 수송 시스템의 기능이 결여된 세균의 표현형에 대한 최근 연구 결과를 토대로 다음과 같은 내용을 기술하였다. 첫째, 세포 내부 인산의 적정 농도 유지를 위한 인산 수송 시스템들의 역할, 둘째, 인산뿐 아니라 여타 환경 신호와 관련된 수송 시스템의 다양한 표현형, 그리고 마지막으로, 수송 시스템들 간 혹은 그 조절자들 간의 표현형 중복을 분류하여 제시하였다. 이러한 내용은 결국 세균의 대사, 적응반응 및 병원성 발현에 미치는 인산 항상성의 중요성을 강조한다. Phosphorous is an essential element for the synthesis of various biomolecules including phospholipids, carbohydrates and nucleic acids. Bacterial cells can uptake it as forms of phosphate and phosphate-containing nutrients from extracellular environments, and reserve extra phosphate to polyphosphate inside the cell. Among five phosphate transport systems, Pst plays central roles in phosphate transport, and its expression is coordinated by the regulation of PhoB-PhoR two component signal transduction system in response to extracellular levels of phosphate. Genomic studies on the response regulator PhoB reveal many genes independent of phosphate metabolism. Based on recent findings on phenotypes of bacteria lacking proper function of each phosphate transport system, this review discusses roles of phosphate transporters in maintaining optimum intracellular phosphate levels, and presents diverse phenotypes of phosphate transporters related with other environmental signals as well as phosphate, then finally points out functional redundancy among phosphate transport systems or their regulators, which emphasize importance of phosphate homeostasis in governing metabolism, adaptation, and virulence of bacteria.

외부 무기인 농도 변화에 의해 조절되는 pst pit 돌연변이 살모넬라주의 arg 및 art 유전자 전사

박윤미 ( Yoon Mee Park ),방일수 ( Iel Soo Bang ) 조선대학교 치의학연구원 2013 Oral Biology Research (Oral Biol Res) Vol.37 No.2

Purpose: Salmonella enterica serovar Typhimurium (S. Typhimurium) can cause salmonellosis, including gastroenteritis and systemic infection in animal hosts such as humans by diet contamination. To replicate and survive in an animal host, S. Typhimurium must compete against host cells for nutrients. Inorganic phosphate (Pi) is an essential element for all organisms and is used for cellular signal transduction and synthesis of various biomolecules. Thus, systems for uptake and homeostasis of Pi are required for cell metabolism. Uptake of Pi in S. Typhimurium is mainly regulated by components of the high-affinity adenosine triphosphate-binding cassette-transport system Pst and low-affinity transporter Pit. To identify genetic factors contributing to homeostasis of Pi, this study investigated the transcriptional profiles of Salmonella mutants lacking Pst and Pit transporters experiencing changes in extracellular Pi. Materials and Methods: Transcriptome of pst pit mutant S. Typhimurium in response to low (0.1 mM) and high (10 mM) extracellular Pi were compared by cDNA microarray analysis, respectively. Results: The results show that transcription of argI encoding ornithine carbamoyltransferase and artJ encoding arginine third transport system was significantly induced. Conclusion: Data suggest a relationship between arginine metabolism and Pi homeostasis in S. Typhimurium.

저산소농도에 의한 질식 지표인자 탐색

정용애,김춘삼,이준배,김준모,방일수 한국법과학회 2022 한국법과학회지 Vol.23 No.2

산소부족 질식사망 규명을 위한 지표인자 연구

이준배,정용애,이수민,방일수,팽기정 한국분석과학회 2020 학술대회논문집 Vol.2020 No.6