• BMB Reports
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• 제40권6호
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• pp.911-920
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• 2007

Tuberculosis, caused by Mycobacterium tuberculosis, continues to be one of the leading infectious diseases to humans. It is urgent to discover novel drug targets for the development of antitubercular agents. The 2-C-methyl-Derythritol-4-phosphate (MEP) pathway for isoprenoid biosynthesis has been considered as an attractive target for the discovery of novel antibiotics for its essentiality in bacteria and absence in mammals. MEP cytidyltransferase (IspD), the third-step enzyme of the pathway, catalyzes MEP and CTP to form 4-diphosphocytidyl-2-C-methylerythritol (CDP-ME) and PPi. In the work, ispD gene from M. tuberculosis H37Rv (MtIspD) was cloned and expressed. With N-terminal fusion of a histidine-tagged sequence, MtIspD could be purified to homogeneity by one-step nickel affinity chromatography. MtIspD exists as a homodimer with an apparent molecular mass of 52 kDa. Enzyme property analysis revealed that MtIspD has high specificity for pyrimidine bases and narrow divalent cation requirements, with maximal activity found in the presence of CTP and $Mg^{2+}$. The turnover number of MtIspD is $3.4 s^{-1}$. The Km for MEP and CTP are 43 and $92{\mu}M$, respectively. Furthermore, MtIspD shows thermal instable above $50^{\circ}C$. Circular dichroism spectra revealed that the alteration of tertiary conformation is closely related with sharp loss of enzyme activity at higher temperature. This study is expected to help better understand the features of IspD and provide useful information for the development of novel antibiotics to treat M. tuberculosis.

• 생명과학회지
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• 제19권10호
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• pp.1438-1443
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• 2009

이 연구는 신장섬유아 세포를 이용하여 LPS에 의해 유도된 신장섬유화 표적유전자인 plasminogen activator inhibitor (PAI-1) 발현과 Ascofuranone (AF)에 의한 신장섬유화 저해효과를 연구하였다. 이 연구를 통해 LPS가 PAI-1의 발현을 농도 및 시간 의존적으로 증가시켜 LPS가 신장섬유화 유도물질임을 확인 할 수 있었다. 또한 LPS로 유도된 PAI-1 mRNA 및 단백질 발현 레벨이 AF에 의해 저해되었으며, 신장섬유화의 또 다른 대표유전자인 fibronectin의 단백질 발현도 AF에 의해 억제되어 AF가 신장섬유화를 저해하는 사실을 확인할 수 있었다. 그리고 AF에 대한 PAI-1 프로모터 활성을 조사하기 위하여 p800-PAI-1-luc을 신장섬유아 세포에 형질전환 시킨 결과, AF가 PAI-1의 전사 활성 조절을 통해 발현을 억제한다는 것을 확인하였다. ERK-1/2의 상위에 존재하는 MEK inhibitor를 처리하여 PAI-1의 발현을 확인한 결과에서도 AF를 처리한 경우와 동일하게 PAI-1 발현이 저해되어 LPS로 유도된 PAI-1의 발현이 ERK-1/2에 의해 조절됨을 알 수 있었다. 또한 LPS로 유도된 ERK-1/2의 인산화가 AF 농도의존적으로 저해된 결과는, AF가 ERK-1/2의 활성저해를 통하여 PAI-1 발현을 조절한다는 사실을 확인 할 수 있었다. 따라서 이러한 연구결과 AF가 신장섬유화를 저해하는 유력한 후보물질로서의 가능성을 제시하였다.

• 미생물학회지
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• 제46권4호
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• pp.359-365
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• 2010

조릿대 근권토양으로부터 분리한 방선균 50균주를 대상으로 고추 세균성 점무늬병원균(Xanthomonas axonopodis pv. vesicatoria)의 항균활성 12균주를 선발하였다. 이들 항균활성 12균주의 계통학적 위치를 검토한 결과, 모두 Streptomyces 속의 Cluster II에 속하는 특징을 나타내었다. JR-24 균주는 최소저해 농도(MIC) 10 ${\mu}l$/disc를 나타내었으며, 배양액 5 ${\mu}l$/ml를 처리 하여 12시간 배양한 결과 Xanthomonas axonopodis pv. vesicatoria에 강한 생육저해효과를 나타내어 최우수 균주로 선발되었다. 항균활성 균주 JR-24의 16S rRNA 유전자 염기서열을 검토한 결과, Streptomyces galbus $DSM40089^T$ (X79852)와 98.1%, Streptomyces longwoodensis $LMG20096^T$ (AJ781356)와 98% 그리고 Streptomyces capoamus $JCM4734^T$ (AB045877)와 97.8%의 상동성을 나타내었다. API 20NE와 API 50CHE를 이용하여 JR-24 균주의 생리 생화학적 특성을 확인한 결과, L-arabinose, D-fructose, D-glucose, D-galactose을 이용하며 gelatin, protein, starch에 대하여 분해능이 있는 것으로 확인되었다. 주요지방산으로는 iso-$C_{14:0}$ (25.93%), iso-$C_{15:0}$ (10.13%), anteiso-$C_{15:0}$ (19.29%) 그리고 iso-$C_{16:0}$ (20.35%) 등을 함유하였으며, 퀴논종은 MK-9 ($H_4$) 4.37%, MK-9 ($H_6$) 51.22% 그리고 MK-9 ($H_8$) 49.47%로 동정되었다. Streptomyces sp. JR-24 균주의 계통학적 특성을 근연종인 Streptomyces galbus $DSM40089^T$와 비교한 결과, 다수의 표현형적 및 계통학적 차이를 나타내었다. 본 연구에서 분리된 Streptomyces sp. JR-24는 친환경 미생물제제 개발을 위한 유전자원 확보에 있어서 매우 큰의의가 있을 것으로 사료 된다.

• Journal of Plant Biotechnology
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• 제40권3호
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• pp.125-134
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• 2013

최근 연구에서 엽록체의 미지의 소기관으로 알려졌던 플라스토글로뷸이 지질 대사에서 중요한 역할을 함이 제시되고 있다. 애기장대 플라스토글로뷸의 프로테옴 단백질 분석은 플라스토글로뷸이 단순히 지질 저장 기관으로써의 기능 뿐아니라 지질 합성 대사에 능동적으로 관여하는 소기관임을 제시하고 있다. 애기장대 플라스토글로뷸에서 34개의 단백질이 발견되었다. 이들을 세 그룹으로 나누어 보면 구조단백질인 플라스토글로불린과 엽록체 대사에 관여하는 효소, 그리고 기능이 미확인된 단백질로 구분 된다. 이들 단백질 유전자의 돌연변이체와 리피도믹스 분석으로 이들 단백질의 기능 규명 연구가 필요하다. 토코페롤 합성의 마지막 단계에 관여하는 VTE1과 VTE4는 엽록체에서 각기 다른 위치에 존재하여 VTE1은 플라스토글로뷸에 존재하나 VTE4는 엽록체 내막에 존재한다. 이 같은 사실은 프레닐퀴논 대사물질이 엽록체 내에서 이동할 가능성을 시사한다. 플라스토글로뷸이 엽록체의 기능을 유지하는데 있어 필수적인지에 대한 유전학 연구가 앞으로 진행되어야 한다. 다양한 스트레스와 발달단계에 따른 플라스토글로뷸의 프로테옴 분석은 지질대사에서 중요한 기능을 하는 신규 단백질을 발견하는데 도움을 줄 것이다. 지금까지 결과로는 플라스토글로뷸은 프레릴퀴논 대사에 있어서 교차로 역할을 함을 제안하고 있다.

• Journal of Microbiology and Biotechnology
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• 제16권10호
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• pp.1554-1560
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• 2006

A Gram-positive, aerobic or facultative anaerobic, non motile, endospore-forming bacterial strain, designated Gsoil $114^T$, was isolated from a soil sample of a ginseng field in Pocheon Province (South Korea), and was characterized taxonomically by using a polyphasic approach. It grew well on nutrient agar medium and utilized a limited number of organic substrates as sole carbon sources, including D-xylose and some other carbohydrates, but did not utilize L-amino acids and organic acids. The isolate was positive for oxidase test but negative for catalase, and negative for degradation of macromolecules such as starch, cellulose, xylan, casein, chitin, and DNA. The G+C content of the genomic DNA was 41.8 mol%. The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major fatty acids were $anteiso-C_{15:0}$ (32.1%), $iso-C_{15:0}$ (30.5%), and $anteiso-C_{17:0}$ (30.2%). Comparative 16S rRNA gene sequence analysis showed that strain Gsoil $114^T$ fell within the radiation of the cluster comprising Bacillus species and joined Bacillus shackletonii LMG $18435^T$ with a bootstrap value of 95%. The highest 16S rRNA gene sequence similarities were found with Bacillus shackletonii LMG $18435^T$ (97.6%), Bacillus acidicola DSM $14745^T$ (96.9%), Bacillus sporothermodurans DSM $10599^T$ (96.5%), and Bacillus oleronius DSM $9356^T$ (96.5%). The phylogenetic distance from any other validly described species within the genus Bacillus was less than 96%. DNA-DNA hybridization experiments showed that the DNA-similarities between strain Gsoil $114^T$ and closest phylogenetic neighbors were less than 39%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil $114^T$ (=KCTC $13944^T$=DSMZ $18134^T$) was classified in the genus Bacillus as the type strain of a novel species, for which the name Bacillus ginsengihumi sp. nov. is proposed.

• Journal of Microbiology and Biotechnology
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• 제31권9호
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• pp.1210-1217
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• 2021

Two gram-negative, catalase-positive, strictly aerobic, and white colony-forming bacteria, strains H242^T and B156^T, were isolated from soil in South Korea. Cells of strain H242^T were oxidase-positive and non-motile short rods, while those of strain B156^T were oxidase-negative and long non-motile rods. Ubiquinone-8 was identified as the sole isoprenoid quinone in both strains. C_16:0, cyclo-C_17:0, andsummed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c) and phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol were identified in both strains as the major cellular fatty acids and polar lipids, respectively. The DNA G+C contents of strains H242^T and B156^T were 69.4 mol% and 69.3 mol%, respectively. Phylogenetic analyses based on 16S rRNA and 92 concatenated core gene sequences revealed that strains H242^T and B156^T formed distinct phylogenic lineages from other Ramlibacter type strains. The DNA-DNA hybridization (DDH) value between strains H242^T and B156^T was 24.6%. Strains H242^T and B156^T were most closely related to Ramlibacter ginsenosidimutans BXN5-27^T and Ramlibacter monticola G-3-2^T with 98.4% and 98.6% 16S rRNA gene sequence similarities, respectively. Digital DDH values between strain H242^T and R. ginsenosidimutans and between strain B156^T and R. monticola were 23.5% and 26.1%, respectively. Phenotypic, chemotaxonomic, and molecular analyses indicated that strains H242^T and B156^T represent two novel species of the genus Ramlibacter, for which the names Ramlibacter terrae sp. nov. and Ramlibacter montanisoli sp. nov., respectively, are proposed. The type strains of R. terrae and R. montanisoli are H242^T (=KACC 21667^T=JCM 33922^T) and B156^T (=KACC 21665^T=JCM 33920^T), respectively.

• Journal of Microbiology and Biotechnology
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• 제33권9호
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• pp.1206-1212
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• 2023

The Wnt/β-catenin pathway plays essential roles in regulating various cellular behaviors, including proliferation, survival, and differentiation [1-3]. The intracellular β-catenin level, which is regulated by a proteasomal degradation pathway, is critical to Wnt/β-catenin pathway control [4]. Normally, casein kinase 1 (CK1) and glycogen synthase kinase-3β (GSK-3β), which form a complex with the scaffolding protein Axin and the tumor suppressor protein adenomatous polyposis coli (APC), phosphorylate β-catenin at Ser45, Thr41, Ser37, and Ser33 [5, 6]. Phosphorylated β-catenin is ubiquitinated by the β-transducin repeat-containing protein (β-TrCP), an F-box E3 ubiquitin ligase complex, and ubiquitinated β-catenin is degraded via a proteasome pathway [7, 8]. Colorectal cancer is a significant cause of cancer-related deaths worldwide. Abnormal up-regulation of the Wnt/β-catenin pathway is a major pathological event in intestinal epithelial cells during human colorectal cancer oncogenesis [9]. Genetic mutations in the APC gene are observed in familial adenomatous polyposis coli (FAP) and sporadic colorectal cancers [10]. In addition, mutations in the N-terminal phosphorylation motif of the β-catenin gene were found in patients with colorectal cancer [11]. These mutations cause β-catenin to accumulate in the nucleus, where it forms complexes with transcription factors of the T-cell factor/lymphocyte enhancer factor (TCF/LEF) family to stimulate the expression of β-catenin responsive genes, such as c-Myc and cyclin D1, which leads to colorectal tumorigenesis [12-14]. Therefore, downregulating β-catenin response transcription (CRT) is a potential strategy for preventing and treating colorectal cancer. Plant cytokinins are N⁶-substituted purine derivatives; they promote cell division in plants and regulate developmental pathways. Natural cytokinins are classified as isoprenoid (isopentenyladenine, zeatin, and dihydrozeatin), aromatic (benzyladenine, topolin, and methoxytopolin), or furfural (kinetin and kinetin riboside), depending on their structure [15, 16]. Kinetin riboside was identified in coconut water and is a naturally produced cytokinin that induces apoptosis and exhibits antiproliferative activity in several human cancer cell lines [17]. However, little attention has been paid to kinetin riboside's mode of action. In this study, we show that kinetin riboside exerts its cytotoxic activity against colon cancer cells by suppressing the Wnt/β-catenin pathway and promoting intracellular β-catenin degradation.