• 한국미생물·생명공학회지
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• 제32권3호
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• pp.282-285
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• 2004

The polyene antibiotics including nystatin, pimaricin, amphotericin and candicidin are a family of most promising antifungal polyketide compounds, typically produced by rare actinomycetes species. The biosynthetic gene clusters for these polyenes have been previously investigated, revealing the presence of highly homologous biosynthetic genes among polyene-producers such as polyketide synthase (PKS) and cytochrome P450 hydroxylase (CYP) genes. Based on amino acid sequence alignment among actinomycetes CYP genes, the highly-conserved regions specific for only polyene CYP genes were identified and chosen for degenerate PCR primers, followed by the PCR-screening with various actinomycetes genomic DNAs. Among tested several polyene non-producing actinomycetes strains, Pseudonorcardia autotrophica strain was selected based on the presence of PCR product with polyene-specific CYP gene primers, and then confirmed to contain a cryptic novel polyene hydroxylase gene in the chromosome. These results suggest that the polyene-specific hydroxylase gene PCR should be an efficient way of screening and isolating potentially-valuable cryptic polyene antibiotic biosynthetic genes from various microorganisms including rare actinomycetes.

• Journal of Microbiology and Biotechnology
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• 제10권2호
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• pp.176-180
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• 2000

Three polyene macrolide antibiotics including two new compounds were isolated from the culture mycelia of a Streptomyces species. The structures of these metabollites were determined as elizabethin, a previously reported 28-membered macrolide and two analohs, using combined spectroscopic methods. These compounds exhibited antifungal activity and cytotoxicity against a juman leukemia cell.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.396-397
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• 2005

The polyene antibiotics are a family of most promising antifungal polyketide compounds, typically produced by actinomycetes species. Using the polyene CYP-specific PCR screening with served actinomycetes genomic DNAs, Pseudonocardia autotrophica strain was identified to contain a unique polyene-specific CYP gene. The genomic DNA library screening using the polyene-specific CYP gene probe revealed the positive cosmid clone containing an approximately 34.5 kb DNA fragment revealed a total of seven complete and two incomplete open reading frame (ORFs), which are highly homologous but unique to previously-known polyene biosynthetic genes. These results suggest that the polyene-specific screening approach should be an efficient way of isolating potectially-valuable cryptic polyene biosynthetic gene cluster from various rare actinomycetes.

• 한국미생물·생명공학회지
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• 제32권3호
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• pp.238-242
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• 2004

D. bryoniae를 원인균으로 하는 참외 만고병에 대해서 항만고병 활성물질을 생산하는 미생물을 방선균으로부터 선별 분리한 후 배양액으로부터 항균활성물질의 규명을 시도하였다. 항진균 물질과 같은 이차대사산물의 생산에 증가시키는 $K_2$$HPO_4$와 칼슘이온이 포함된 GSS배지에서 방선균 SKM338 균주를 180 rpm, $30^{\circ}C$, 5일 동안 배양하여 얻어진 배양 상등액으로부터 물리화학적인 방법으로 항진균 활성이 있는 물질을 분리 정제한 결과 참외의 만고병에 대한 생물농약으로 개발 가능한 방선균 유래의 항진균성 물질은 NMR, IR, UV 및 Mass spectral data 분석 등을 통해 polyene macrolide계에 속하는 항생물질인 Flavofungin, Fungichromin, Filipins로 밝혀졌으며 이들의 응용을 기대해 본다.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.204-208
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• 2002

A Streptomyces sp. isolated from a soil sample collected in Taejeon, Korea has previously been found to produce two new polyene antibiotics. The two new antibiotics were named "16-methyloxazolomycin (antibacterial)" and "tetrin C (antifungal)", and their chemical structures are presented elsewhere [10, 11]. In the current study, chemotaxonomy, numerical taxonomy, and ISP methods were all employed for the taxonomic study. The spore chains were spirales and the spore surface was smooth. The spore mass was a gray series and no melanin pigment was produced. On the basis of the morphological and physiological properties, the microorganism was identified to be Streptomyces erumpens, belonging to the gray series of category IV, as defined by Bergey′s Manual. Tetrin C at the concentration of 20 ${\mu}g$/ml demonstrated a potent in vivo (pot test) preventive effect against rice blast, rice sheath blight, cucumber gray mold, wheat powdery mildew, and barley leaf rust.

• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.212-215
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• 2004

In order to develop a biocontrol agent that can effectively control Fusarium wilt on Cymbidium genus, the effectiveness of antagonistic microbes against the cause pathogen was screened. The selected microbe showed a broad spectrum of antifungal activity, and the culture broth of this microbe had better preventive effect on Fusarium wilt than the commercial chemical agent in the pot assay. This isolated strain, GBA-12, was identified as Streptomyces kasugaensis, and the antifungal substance was purified from a broth culture of GBA-12. This purified substance was identified as a polyene macrolide (YS-822A) that was newly discovered from Streptomyces kasugaensis, and it exhibited antifungal activity against several phytopathogenic fungi.

• KSBB Journal
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• 제22권4호
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• pp.218-221
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• 2007

본 연구에서는 초음파 파쇄기를 이용하여 폴리엔 항진균 활성을 갖는 방선균 배양액으로부터 pellet을 회수하여 미생물농약으로 사용이 용이한 포자를 확보하기 위한 최적화 연구를 수행하였다. 그 결과, Streptomyces sp. MMBL001, MMBL003 그리고 Pseudonocardia autotrophica는 각각 12%, 18%, 12% 출력 (100%, 700 W)에서 최적의 포자 전환율을 보임을 확인하였다. 이렇게 확보한 포자를 10% skim milk 보호제를 사용하여 동결건조한 후 각각의 생균수를 측정한 결과, MMBL003이 MMBL001과 P. autotrophica에 비해 3배 이상의 생균수가 유지됨이 측정되었다. C. albicans를 대상으로 항진균 효과를 확인한 결과, 동결건조된 3종의 방선균주 모두 우수한 항진균 활성을 유지함으로써 신규 폴리엔 생산 방선균을 이용한 미생물농약으로서의 활용 가능성을 제시하였다.

• Journal of Microbiology and Biotechnology
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• 제32권7호
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• pp.911-917
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• 2022

As valuable antibiotics, microbial natural products have been in use for decades in various fields. Among them are polyene compounds including nystatin, amphotericin, and nystatin-like Pseudonocardia polyenes (NPPs). Polyene macrolides are known to possess various biological effects, such as antifungal and antiviral activities. NPP A1, which is produced by Pseudonocardia autotrophica, contains a unique disaccharide moiety in the tetraene macrolide backbone. NPP B1, with a heptane structure and improved antifungal activity, was then developed via genetic manipulation of the NPP A1 biosynthetic gene cluster (BGC). Here, we generated a Streptomyces artificial chromosomal DNA library to isolate a large-sized NPP B1 BGC. The NPP B1 BGC was successfully isolated from P. autotrophica chromosome through the construction and screening of a bacterial artificial chromosome (BAC) library, even though the isolated 140-kb BAC clone (named pNPPB1s) lacked approximately 8 kb of the right-end portion of the NPP B1 BGC. The additional introduction of the pNPPB1s as well as co-expression of the 32-kb portion including the missing 8 kb led to a 7.3-fold increase in the production level of NPP B1 in P. autotrophica. The qRT-PCR confirmed that the transcription level of NPP B1 BGC was significantly increased in the P. autotrophica strain containing two copies of the NPP B1 BGCs. Interestingly, the NPP B1 exhibited a previously unidentified SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) inhibition activity in vitro. These results suggest that the Streptomyces BAC cloning of a large-sized, natural product BGC is a valuable approach for titer improvement and biological activity screening of natural products in actinomycetes.

• 한국미생물·생명공학회지
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• 제23권3호
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• pp.329-336
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• 1995

For the development of new antitumor antibiotics produced by microorganisms, Streptomyces sp. YBE-316 was isolated from soil. The productivity of the antitumor antibiotic from Streptomyces sp. YBE-316 gradually increased after 60 hours, and was maximum after 100 hours after inoculation in growth medium (2.0% sucrose, 1.0% soybean meal, 0.1% K$_{2}$HPO$_{4}$, pH 7.0) at 30$\circ$C, 150 rpm, 5 NL/min by 30 l jar fermentor. This antitumor antibiotic was present only in mycelium, and stable in pH 5.0-10.0 for 20 minutes at 100$\circ$C. Antitumor and antibiotic activities were maintained at neutral pH, and heat stability was low. This antitumor antibiotic was soluble in methanol and ethanol, and insoluble in water, ethyl acetate, chloroform, and n-hexane. This antitumor antibiotic was sequentially purified by acetone extraction from mycelium, butanol extraction, and silica gel column chromatography. Antitumor activity was low against most tested cell lines, but antibiotic activity was high and low against yeasts and bacteria, respectivelv. The visualization test showed that this antitumor antibiotic had higher hydroxyl, ketone, amino, carboxyl groups, and sugar(s) in its structure. Instrumental analyses showed that this antitumor antibiotic was a pentaene in polyene class antibiotics. In pentaene class antibiotics, this was considered as an eurocidin or capacidin type antibiotics. The molecular weight of this antitumor antibiotic was higher than 683.0 daltons, and this antitumor antibiotic might be glycosylated by other sugar(s), instead of mycosamine or perosamine, an amino sugar.

• Applied Biological Chemistry
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• 제45권2호
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• pp.114-118
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• 2002

점액세균의 대사산물을 대상으로 새로운 항암활성물질을 탐색하는 과정에서 해양퇴적물에서 분리한 균주 JW111의 균체 추출액이 인체유래의 각종 암세포에 대해 강한 활성을 나타냄을 발견하고, 먼저 생산균주인 JW111이 Myxococcus stipitatus임을 확인한 후 그 대사산물을 분리, 정제하여 구조결정한 결과, Phenalamide $A_1$, $A_2E, $A_3$임을 밝혔다. 이들은 공시된 감수성 암세포에 대해 모두 우수한 활성을 나타내었으며, $IC_50$의 값은 $0.23{\sim}0.50{\mu}g/ml$이었다. 또한 이들은 Adriamycin의 내성 세포주에 대해서도 감수성 세포주와 동일한 활성을 나타내어 내성을 나타내지 않음이 확인되었다.