• 대한화학회지
• /
• 제40권9호
• /
• pp.623-629
• /
• 1996

지의류에 속하는 Umbiliciaria vellea 중 에탄올 분획의 항균활성 물질을 규명하기 위하여 silica겔 컬럼 크로마토그래피 및 재결정법으로 화합물 I과 II를 순수히 분리정제하여 그 구조와 항균활성을 측정하였다. 정제된 화합물I은 Cryptococcus neoformance 등의 균에 대한 항진균활성과, Pseudomonas aeruginosa등의 균에 대한 항세균 활성이 있었다. 이 물질의 녹는점은 129~132$^{\circ}C$였고, 217, 265 및 330 nm의 UV 최대흡광을 보였다. 그리고 EI-mass에서 측정된 분자이온은 m/z 196이었고, 원소분석 결과 분자식은 $C_{10}H_{12}O_4$였으며 IR 및 NMR 스펙트라로부터 이 물질이 ethyl 2,4-dihydroxy-6-methyl benzoate임을 확인하였다. 화합물 II의 녹는점은 58~59$^{\circ}C$였고, 212, 276 및 282 nm의 UV 최대흡광을 보였다. 이 물질의 분자이온은 m/z 124였고, $C_7H_8O_2$의 분자식을 갖는 5-methyl-1,3-benzenediol임을 확인하였다.

• Mycobiology
• /
• 제36권3호
• /
• pp.173-177
• /
• 2008

The crude ethanol extracts (stem and fruits), their fractions and two triterpenes, $\beta$-Amyrin and 12-Oleanene 3$\beta$, 21$\beta$-diol, isolated as a mixture from the chloroform soluble fraction of an ethanolic extract of Duranta repens stem, were evaluated for antibacterial, antifungal activities by the disc diffusion method and cytotoxicity by brine shrimp lethality bioassay. The structures of the two compounds were confirmed by IR, $^1H$-NMR, $^{13}C$-NMR and LC-MS spectral data. The chloroform soluble fraction of stem and ethanol extract of fruits possess potent antishigellosis activity and also exhibited moderate activity against some pathogenic bacteria and fungi but the isolated compound 1 (mixture of $\beta$-Amyrin and 12-Oleanene 3$\beta$, 21$\beta$-diol) showed mild to moderate inhibitory activity to microbial growth. The minimum inhibitory concentrations (MICs) of the extracts (stem and fruits), their fractions and compound 1 were found to be in the range of 32$\sim$128 ${\mu}g/ml$. The chloroform soluble fractions of stem and ethanol extract of fruit showed significant cytotoxicity with $LC_{50}$ value of 0.94 ${\mu}g/ml$ and 0.49 ${\mu}g/ml$, respectively against brine shrimp larvae.

• 농약과학회지
• /
• 제16권1호
• /
• pp.1-10
• /
• 2012

Diarylthiazole 화합물인 4-[5-(2-cyclopropylaminopyrimidin-4-yl)-4-(4-fluorophenyl)thiazol-5-yl]-1-methylpiperidine (I)의 식물병원균에 대한 살균활성은 우수하다고 알려져 있으며, 본 연구의 선도물질로 사용되었다. 화합물(I)의 4-fluorophenyl기 대신 4-fluoro-3-methylphenyl, 4-fluoro-3-chlorophenyl, 4-chloro-2-fluorophenyl, 4-bromo-3-methylphenyl와 2,4-dichlorophenyl기 로, 2-N-methylpiperidine-4-yl-thiazol 대신 2-amino-, 2-(N-ethoxycarbonyl)piperidin-4-yl-, and 2-piperidin-4-yl-thiazole로 치환하여 합성하였다. 새로운 VIII-1~VIII-5, XIII-1~XV-5 화합물들을 합성하였고, 1H-NMR-spectrum으로 구조를 확인하였다. Phytophthora capsici에 대한 모든 합성 화합물들의 살균활성은 whole plant법으로 시험하였고, 그 결과 VIII-1~VIII-5, XIII-1~XV-5 화합물들 중 XIV-3이 in vivo 에서 가장 우수한 살균활성을 나타내었다. 상용되고 있는 살균제인 dimethomorph와 화합물 I의 $EC_{50}$ 과 $EC_{90}$ 값이 각각 $4.26{\pm}0.02$, $14.72{\pm}0.05$와 $1.01{\pm}0.11$, $6.31{\pm}0.09mM$인 반면, 4-[5-(2-cyclopropylaminopyrimidin-4-yl)-4-(4-chloro-2-fluorophenyl)thiazol-5-yl]-1-methylpiperidine (XIV-3)은 $0.98{\pm}0.21$과 $5.85{\pm}0.05mM$을 나타내었다. 따라서, 화합물 XIV-3은 P. capsici 에 의해 발생하는 식물병에 대하여 식물보호제로서의 가능성을 보여주었으며, 화합물 XIV-3에 대한 작용 메커니즘에 대한 연구가 필요할 것이라 사료된다.

• Archives of Pharmacal Research
• /
• 제25권6호
• /
• pp.807-816
• /
• 2002

Dihydrofolate reductases (DHFR) of human, Candida albicans and E. coli were docked with their original ligands of X-ray crystal complex using QXP (Quick eXPlore), a docking program. Conditions to reproduce the crystal structures within the root mean square deviation (rmsd) of 2.00 $\AA$ were established. Applying these conditions, binding modes and species-specificities of a novel antibacterial compound, $N^4-(2-acetoxyethoxymethyl)-2-acetylpyridine$ thiosemicarbazone (MTSC), were studied. As the results, the docking program reproduced the crystal structures with average rmsd of six ligands as 0.91 $\AA$ ranging from 0.49 to 1.45 $\AA$. The interactions including the numbers of hydrogen bonds and hydrophobic interactions were the same as the crystal structures and superposition of the crystal and docked structures almost coincided with each other. For AATSC, the results demonstrated that it could bind to either the substrate or coenzyme sites of DHFR in all three species with different degrees of affinity. It confirms the experimentally determined kinetic behavior of uncompetitive inhibition against either the inhibitor or the coenzyme. The docked MTSC overlapped well with the original ligands and major interactions were consistent with the ones in the crystal complexes. The information generated from this work should be useful for future development of antibacterial and antifungal agents.

• 한국균학회소식:학술대회논문집
• /
• 한국균학회 2015년도 춘계학술대회 및 임시총회
• /
• pp.20-20
• /
• 2015

Endophytic fungi are microorganisms inhabiting living plant tissues without causing apparent harm to the host. They are drawing increasing attention due to their ability to produce various bioactive compounds as well as their effects on host growth and resistance to biotic and abiotic stresses. As a first step to assess biodiversity of plant associated fungi in Korea and the following evaluation on diverse biological activities, we are collecting endophytic fungi from plant in wild followed by systematic long-term storage in liquid nitrogen. Molecular identification using ITS sequences was also incorporated for pure culture by hyphal tip isolation. As of April 2015, about 1,400 fungal strains had been isolated from about 170 plant taxa. Fungal isolates belonging to Pleosporales, Diaporthales, Glomerellales, Hypocreales, and Xylariales were the most abundant. These collections are being used for several complementary researches, including screening of isolates with novel bioactive compounds or conferring drought stress resistance, phylogenetic and genomic study. Genome sequencing was performed for 3 isolates, one Xylaria sp. strain JS573 producing griseofulvin, an antifungal compound, and two Fusarium spp. strains JS626 and JS1030, which are assumed to be new species found in Korea. More detailed analysis on these genomes will be presented. These collections and genome informations will serve as invaluable resources for identifying novel bioactive materials in addition to expand our knowledge on fungal biodiversity.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2005년도 생물공학의 동향(XVI)
• /
• pp.420-422
• /
• 2005

TMC (Tautomycetin) is a liner polyketide immunosuppressive antifungal compound produced by Streptomyces spp. Inhibition of T cell proliferation with TMC was observed highly efficient at 100-fold lower than those needed to achieve maximal inhibition with cyclosporin A. To elucidate the biosynthetic pathway of TMC, a genomic DNA library was constructed using a E. coil-Streptomyces shuttle cosmid vector, pOJ446. The DNA libraries were screened by colony blot hybridization using several polyketide ${\beta}-ketosynthase$ (KS) probes amplified from TMC-producing Streptomyces genomic DNA using polymerase chain reaction (PCR), of which the degenerate primers were designed based on the highly conserved sequences present in KS domains of various type I polyketide synthase genes in Streptomyces species. This library construction and screening approach led to the isolation of several positive cosmid clones representing type I polyketide biosynthetic gene clusters. In addition, a Streptomyces regulatory gene called afsR2 (a global regulatory gene stimulating antibiotic production in both S. coelicolor and S. lividans) was successfully integrated into the TMC-producing Streptomyces chromosome via E. coil-Streptomyces heterologous conjugation mehtod. The more detailed results of production improvement and genetic characterization of TMC-producing Streptomyces spp. will be discussed.

• 한국미생물·생명공학회지
• /
• 제17권4호
• /
• pp.307-312
• /
• 1989

77-AG-567 균주는 Pyricularia oryzae와 Sphasrotheca fuliginea에 대한 항균활성을 나타냈다. 활성 물질을 정제해 가는 과정에서 이 균주는 blasticidin S와 또 다른 항생물질을 동시에 생산한다는 사실을 알았다. 이 화합물은 UV 및 $^1$H NMR 스펙트럼에 의해 E-73이라고도 일컬어지는 acetoxycycloheximide로 밝혀졌다. 균주를 동정해본 결과 77-AG-567균주는 Streptomyces atbutus로 판단되며 지금까지 blasticidin S와 acetoxycycloheximide를 동시에 생산하는 것으로 알려져 온 S. albulus와는 다른 특성을 나타냈다. 특히 주목할만한 차이점은 포자의 표면이였다. 또한 acetoxycycloheximide는 지금까지 효모와 종양세포에만 생리활성을 나타내는 것으로 알려져 왔으나 본 실험결과 Pyricularia oryzae와 Sphasrotheca fuliginea에도 항균활성을 가진다는 사실을 알았다.

• Journal of Microbiology and Biotechnology
• /
• 제16권7호
• /
• pp.1158-1162
• /
• 2006

The glyoxylate cycle can conserve carbons and adequately supply tricarboxylic acid (TCA) cycle intermediates for biosynthesis when microorganisms grow on $C_{2}$ carbon sources. It has been reported that isocitrate lyase (ICL1), a key enzyme of the glyoxylate cycle, is highly induced when Magnaporthe grisea, the causal agent of rice blast, infects its host. Therefore, the glyoxylate cycle is considered as a new target for antifungal agents. A 1.6-kb DNA fragment encoding the ICL1 from M. grisea KJ201 was amplified by PCR, cloned into a vector providing His-tag at the N-terminus, expressed in Escherichia coli, and purified using Ni-NTA affinity chromatography. The molecular mass of the purified ICL1 was approximately 60 kDa, as determined by SDS-PAGE. The ICL1 inhibitory effects of TCA cycle intermediates and their analogs were investigated. Among them, 3-nitropropionate was found to be the strongest inhibitor with an $IC_{50}$ value of $11.0{\mu}g/ml$. 3-Nitropropionate inhibited the appressorium development in M. grisea at the ${\mu}M$ level, whereas conidia germination remained unaffected. This compound also inhibited the mycelial growth of the fungus on minimal medium containing acetate as a $C_{2}$ carbon source. These results suggest that ICL1 plays a crucial role in appressorium formation of M. grisea and is a new target for the control of phytopathogenic fungal infection.

• Journal of Microbiology and Biotechnology
• /
• 제14권3호
• /
• pp.525-531
• /
• 2004

A strain antagonistic to Fusarium solani, CHO104, was selected from approximately 100 microorganisms isolated from soil. Strain CHO104 was identified as Bacillus amyloliquefaciens and found to be Gram-positive based on the Biolog system and 16S rRNA methods. A culture broth of B. amyloliquefaciens CHO104 also exhibited antimicrobial activity against various microorganisms. As such, the EtOAc extract of the culture broth was isolated by various column chromatographic procedures and HPLC. The antimicrobial and antifungal substance was then characterized as macrolactin A $(C_{24}H_{34}O_5)$ using high-resolution EI-MS and NMR analyses, and found to be very effective in inhibiting the growth of Staphylococcus aureus, E. coli, and Botrytis cinerea, even when using a concentration of one-twentieth of the benzoic acid as the control compound.

• 한국미생물·생명공학회지
• /
• 제10권1호
• /
• pp.39-43
• /
• 1982

항진균성 항생물질 생산균으로 분리된 Streptomyces균 No. 297 균의 배양액으로부터 항균물질을 분리·정제하여 침상결정을 얻었다. 이 물질은 UV. IR. spectra, NMR, Mass-spectra 및 여러 화학반응시험을 통하여 t-cin-namamide로 동정되었다. 항균 spectra를 조사해본 결과 Pellicularia sasakii, Pyricularia oryzae 기타 및 병원성 진균류에 강한 항균성을 나타내며 세균류에는 항균력이 극히 약한 것이 특징이다.