• Natural Product Sciences
• /
• 제13권1호
• /
• pp.90-96
• /
• 2007

Bioactivity guided fractionation of the cultured filtrates of Aspergillus versicolor, which was derived from a marine sponge Petrosia sp., yielded three polyketides: decumbenones A (1),B (2), and versiol (3). These compounds were identified on the basis of 1D and 2D NMR spectroscopic and MS analysis. The absolute configuration was defined by the modified Mosher's method. The isolated compounds were tested for cytotoxicity against a panel of five human solid tumor cell lines and antibacterial activity against twenty clinically isolated methicillin-resistant strains. This is the first report on the isolation of these compounds from a marine source.

• The Plant Pathology Journal
• /
• 제28권1호
• /
• pp.93-100
• /
• 2012

The rhizobacterium NJ134, showing strong $in$ $vitro$ antifungal activity against $Fusarium$ $oxysporum$, was isolated from field grown tomato plants and identified as $Pseudomonas$ sp. based on 16S ribosomal DNA sequence and biochemical analyses. The antifungal compound purified by gas chromatography-mass spectrometry, infrared, and nuclear magnetic resonance analyses from NJ134 cultures was polyketide 2,4-diacetylphloroglucinol (DAPG). Analysis of the sequence of part of one of the genes associated with DAPG synthesis, $phlD$, indicated that the DAPG producer NJ134 was a novel genotype or variant of existing genotype termed O that have been categorized based on isolates from Europe and North America. A greenhouse study indicated that about $10^8$ CFU/g of soil NJ134 culture application was required for effective biocontrol of Fusarium wilt in tomato. These results suggest that a new variant genotype of a DAPG-producing strain of $Pseudomonas$ has the potential to control Fusarium wilt under the low disease pressure conditions.

• Journal of Microbiology and Biotechnology
• /
• 제20권11호
• /
• pp.1484-1490
• /
• 2010

In the Streptomyces hygroscopicus JCM4427 geldanamycin biosynthetic gene cluster, five putative regulatory genes were identified by protein homology searching. Among those genes, gel14, gel17, and gel19 are located downstream of polyketide synthase genes. Gel14 and Gel17 are members of the LAL family of transcriptional regulators, including an ATP/GTP-binding domain at the N-terminus and a DNA-binding helix-turn-helix domain at the C-terminus. Gel19 is a member of the TetR family of transcriptional regulators, which generally act to repress transcription. To verify the biological significance of the putative regulators in geldanamycin production, they were individually characterized by gene disruption, genetic complementation, and transcriptional analyses. All three genes were confirmed as positive regulators of geldanamycin production. Specifically, Gel17 and Gel19 are required for gel14 as well as gelA gene expression.

• Journal of Microbiology and Biotechnology
• /
• 제28권7호
• /
• pp.1068-1077
• /
• 2018

DKxanthenes are a class of yellow secondary metabolites produced by myxobacterial genera Myxococcus and Stigmatella. We identified a putative 49.5 kb DKxanthene biosynthetic gene cluster from Myxococcus stipitatus DSM 14675 by genomic sequence and mutational analyses. The cluster consisted of 15 genes (MYSTI_06004-MYSTI_06018) encoding polyketide synthases, non-ribosomal peptide synthases, and proteins with unknown functions. Disruption of the genes by plasmid insertion resulted in defects in the production of yellow pigments. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry analyses indicated that the yellow pigments produced by M. stipitatus DSM 14675 might be novel DKxanthene derivatives. M. stipitatus did not require DKxanthenes for the formation of heat-resistant viable spores, unlike Myxococcus xanthus. Furthermore, DKxanthenes showed growth inhibitory activity against the fungi Aspergillus niger, Candida albicans, and Rhizopus stolonifer.

• 식물병연구
• /
• 제20권3호
• /
• pp.216-218
• /
• 2014

Lysobacter antibiocus HS124 is a chitinase-producing rhizobacterium with proven capacities to suppress plant diseases. Bacterial cultures of L. antibioticus HS124 showed strong biocontrol efficacies against various plant diseases compared to those of bacterial cultures of Bacillus subtilis QST713 which is an active ingredient of a commercial biopesticide, Serenade. Here, we report the draft genome sequence and automated annotation of strain HS124. This draft genome sequence indicates the novelty of L. antibiocus HS124 and a subset of gene functions that may be related to its biocontrol activities.

• Molecules and Cells
• /
• 제26권3호
• /
• pp.278-284
• /
• 2008

An open reading frame, designated GerGTII and located downstream of the polyketide synthase genes, has been identified as a chalcosyltransferase by sequence analysis in the dihydrochalcomycin biosynthetic gene cluster of Streptomyces sp. KCTC 0041BP. The deduced product of gerGTII is similar to several glycosyltransferases, authentic and putative, and it displays a consensus sequence motif that appears to be characteristic of a sub-group of these enzymes. Specific disruption of gerGTII within the S. sp. KCTC 0041BP genome by insertional in-frame deletion method, resulted complete abolishment of dihydrochalcomycin and got the 20-O-mycinosyl-dihydrochalconolide as intermediate product in dihydrochalcomycin biosynthesis which was confirmed by electron spray ionization-mass spectrometry and liquid chromatography-mass spectrometry. Dihydrochalcomycin also was recovered after complementation of gerGTII.

• 한국미생물·생명공학회지
• /
• 제51권1호
• /
• pp.128-131
• /
• 2023

Here we report the draft genome sequence of Weissella koreensis strain HJ and genomic analysis of its key features. The genome consists of 1,427,571 bp with a GC content of 35.5%, and comprises 1,376 coding genes. In silico analysis revealed the absence of pathogenic factors within the genome. The genome harbors several genes that play an important role in the survival of the gastrointestinal tract. In addition, a type III polyketide synthase cluster was identified. Pangenome analysis identified 68 unique genes in W. koreensis strain HJ. The genome information of this strain provides the basis for understanding its probiotic properties.

• 생약학회지
• /
• 제54권1호
• /
• pp.16-20
• /
• 2023

KSM-2690 B (1), a peptide-polyketide hybrid compound, was discovered from an actinomycete strain (CJD 1) isolated from Dong-Baek hill on Jeju Island, Republic of Korea. The chemical structure of 1 was identified by using NMR, MS, and UV spectroscopic analyses. Careful analysis of 1D and 2D NMR data revealed that KSM-2690 (1) has an oxazole ring, a β-lactone-γ-lactam spirocycle ring, and both triene and diene structures. KSM-2690 B (1) showed inhibitory activities against E. coli at 200 ㎍/mL.

• 식물병연구
• /
• 제18권4호
• /
• pp.310-316
• /
• 2012

Gibberellea fujikuroi (Gf) 종복합체는 최소 15개의 종으로 구성되어 있으며, 대부분 식물에 병을 일으킬 뿐 아니라 푸모니신과 같은 곰팡이독소를 생성한다. 본 연구에서는 우리나라 벼와 옥수수로부터 분리한 Gf 종복합체 소속 야생형 균주의 푸모니신 생성능을 검정하였다. 이들 분석대상 균주는 모두 푸모니신 생합성에 필수적인 polyketide synthase 유전자 FUM1을 가지고 있는 것으로 확인되었다. 총 88주의 Gf 종복합체 소속 균주(55 F. fujikuroi, 10 F. verticillioides, 20 F. proliferatum, 2 F. subglutinans, 1 F. concentricum)와 Gf 종복합체의 근연종인 4주의 F. commune를 쌀 배지에 배양한 후 각 균주의 푸모니신 생성 농도를 HPLC 방법으로 측정하였다. 대부분의 F. verticillioides과 F. proliferatum 균주는 기주 식물에 관계없이 푸모니신 $B_1$($0.5-2,686.4{\mu}g/g$)과 $B_2$($0.7-1,497.6{\mu}g/g$)를 다양한 범위 내에서 생성하였다. 반면 모든 F. fujikuroi을 비롯한 다른 Fusarium spp.의 균주로부터는 푸모니신이 검출되지 않았거나 $10{\mu}g/g$ 이하 수준의 미량만 검출되었다. 흥미롭게도 F. proliferatum과 F. fujikuroi의 경우, 옥수수 유래 균주 집단에서 벼 유래 균주 집단에 비해 상대적으로 고농도 푸모니신 생성 균주의 비율이 높았다. 한편, FUM1 유전자를 함유하고 있는 F. commune의 푸모니신 생성능은 본 연구를 통해 처음 보고된다.

• 한국미생물·생명공학회지
• /
• 제44권3호
• /
• pp.391-399
• /
• 2016

Melithiazol은 점액세균 Melitangium lichenicola, Archangium gephyra, Myxococcus stipitatus에 의해 생산되는 항진균 물질이다. M. lichenicola의 melithiazol 생합성 유전자는 이미 알려져 있지만, A. gephyra와 M. stipitatus의 melithiazol 생합성 유전자들은 아직까지 밝혀져 있지 않다. 본 연구에서는 유전체 서열 분석과 돌연변이 분석을 통해 M. stipitatus DSM 14675 균주로부터 37.3 kb 크기의 melithiazol 생합성 유전자군을 발견하였다. 이 유전자군은 9개(MYSTI_04973−MYSTI_04965)의 유전자로 구성되어 있는데, 4개의 polyketide synthase 모듈과 3개의 non-ribosomal peptide synthase 모듈, 그리고 fumarylacetoacetate hydrolase, S-adenosylmethionine-dependent methyltransferase, nitrilase를 암호화하는 것으로 분석되었다. 플라스미드 삽입 돌연변이를 통해 MYSTI_04972 유전자 또는 MYSTI_04973를 불활성화시켰을 때 melithiazol 생산능이 상실되었다. MYSTI_04972부터 MYSTI_04965까지의 8개 유전자가 암호화하는 melithiazol 생합성 모듈의 구성은 M. lichenicola Me l46에서와 유사하였다. 하지만 첫 번째 유전자(MYSTI_04973)에 의해 암호화되는 로딩 모듈의 구성은 M. lichenicola Me l46과 달랐는데, 이러한 차이는 M. stipitatus 균주들이 어떻게 M. lichenicola Me l46과는 다른 구조의 melithiazol 유도체들을 생산하는지 설명해준다.