• 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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• 제25권5호
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• pp.658-661
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• 2015

Genes encoding enzymes with sequence similarity to hopanoids biosynthetic enzymes of other organisms were cloned from the hopanoid (hop) gene cluster of Streptomyces peucetius ATCC 27952 and transformed into Streptomyces venezuelae YJ028. The cloned fragments contained four genes, all transcribed in one direction. These genes encode polypeptides that resemble polyprenyl diphosphate synthase (hopD), squalene-phytoene synthases (hopAB), and squalene-hopene cyclase (hopE). These enzymes are sufficient for the formation of the pentacyclic triterpenoid lipid, hopene. The formation of hopene was verified by gas chromatography/mass spectrometry.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.403-408
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• 2009

A number of bifidobacterial species of human origin were screened for the presence of cryptic plasmids. One strain, Bifidobacterium longum FI10564, harbored plasmids of approximately 2.2 kb, 3.6 kb, and 4.9 kb in size. The smallest plasmid, pFI2576(2,197 bp), was studied in detail and its complete nucleotide sequence was determined. Computer-assisted analysis of this novel plasmid(G+C content 62%) identified 9 putative open reading frames(orfs), 3 of which were shown to be probable genes. These putative genes are arranged in an operon-like structure, in which the overlapping orfs 1 and 2 encode putative Rep proteins and are highly homologous to the rep genes of the B. longum plasmid pMBI(1,847 bp). The mechanism of replication of pFI2576 was investigated using Southern blot analysis of whole cell lysates, with and without S1 nuclease treatment, and atomic force microscopy(AFM). The results indicate that pFI2576 is likely to use the theta mode of replication.

• Journal of Ecology and Environment
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• 제37권4호
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• pp.395-410
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• 2014

The genus Callophyllis is recorded as six separate species with imprecise species delimitation in Korea. To elucidate the species boundaries of Korean Callophyllis, we performed morphological observations and molecular analyses, and included three Japanese Callophyllis species from the type locality. From the results of molecular analyses using plastid rbcL and mitochondrial COI-5P genes, we confirmed ten Callophyllis species, including five cryptic ones: C. adhaerens, C. adnata, C. crispata, and C. japonica from Korea and Japan; C. hayamensis as an unrecorded species from Korea; C. cartilaginea, C. mollitia, C. repens, C. serratifolia, and C. undulata as new species from Korea. There were no Korean specimens that matched C. adnata or C. crispata from Japan, except Korean C. japonica, which formed a genetic group with the Japanese species. We obtained the interspecific divergences among the five cryptic species as 0.6-4.5% in rbcL and 2.8-8.4% in COI-5P. We recognized that the species diversity of Callophyllis has been underestimated from the northwestern Pacific region. The species boundary of Callophyllis from Korea and Japan will be a cornerstone to revealing the phylogenetic affinity of the genus distributed in both hemispheres of the western Pacific.

• BMB Reports
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• 제50권4호
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• pp.162-163
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• 2017

RNA polymerase II-interacting the Set2 methyltransferase co-transcriptionally methylates histone H3 at lysine 36 within the body of genes. This modification facilitates histone deacetylation by Rpd3S HDAC in 3' transcribed regions to suppress cryptic initiation and slow elongation. Although this pathway is important for global deacetylation, no strong effects have been seen on genome-wide transcription under optimized laboratory conditions. In contrast, this pathway slows the kinetics of mRNA induction when target genes are induced upon environmental changes. Interestingly, a majority of Set2-repressed genes are overlapped by a lncRNA transcription that targets H3K36 methylation and deacetylation by Rpd3S HDAC to mRNA promoters. Furthermore, this pathway delays the induction of many cryptic transcripts upon environmental changes. Therefore, the Set2-Rpd3S HDAC pathway functions to fine-tune expression dynamics of mRNAs and ncRNAs.

• The Plant Pathology Journal
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• 제17권2호
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• pp.77-82
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• 2001

Erwinia amylovora causes a devastating disease called fire blight in rosaceous trees and shrubs such as apple, pear, and raspberry. To successfully infect its hosts, the pathogen requires a set of clustered genes termed hrp. Studies on the hrp system of E. amylovora indicated that it consists of three functional classes of genes. Regulation genes including hrpS, hrpS, hrpXY, and hrpL produce proteins that control the expression of other genes in the cluster. Secretion genes, many of which named hrc, encode proteins that may form a transmembrane complex, which is devoted to type III protein secretion. Finally, several genes encode the proteins that are delivered by the protein secretion apparatus. They include harpins, DspE, and other potential effector proteins that may contribute to proliferation of E. amylovora inside the hosts. Harpins are glycine-rich heat-stable elicitors of the hypersensitive response, and induce systemic acquired resistance. The pathogenicity protein DseE is homologous and functionally similar to an avirulence protein of Pseudomonas syringae. The region encompassing the hrpldsp gene cluster of E. amylovora shows features characteristic of a genomic island : a cryptic recombinase/integrase gene and a tRNA gene are present at one end and genes corresponding to those of the Escherichia coli K-12 chromosome are found beyond the region. This island, designated the Hrp pathogenicity island, is more than 60 kilobases in size and carries as many as 60 genes.

• 생태와환경
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• 제52권4호
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• pp.385-393
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• 2019

Chironomid communities are indicators of water pollution because of their ability to thrive under freshwater conditions. However, it is difficult to distinguish between chironomid larvae based on morphology. DNA barcoding, based on nucleotide sequences of marker genes, can be used to identify chironomid larvae. Samples of chironomid larvae were collected from Gwangju Stream and Pungyeongjeong Stream, tributaries of the Yeongsan River in South Korea. We identified 3 subfamilies, 13 genera, 16 species, and 1 cryptic species. There were 7 genera and 10 species from the subfamily Chironominae, 5 genera and 5 species from subfamily Orthocladiinae, 1 genus and 1 species from subfamily Tanipodinae, and the cryptic chironomid species of the family Chironomidae. There were 21 individuals from, 7 species and 1 cryptic species from the Gwangju Stream and 24 individuals, belonging to 10 species from the Pungyeongjeong Stream. The only species detected in both streams was Cricotopus bicinctus. The relationship between water quality and the species detected was difficult to explain, but the number of species showed a tendency to increase at sites where water quality was poor. Additional investigations and studies are needed to understand the relationship between water quality and the chironomid species occurring in these two streams.

• 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.

• 미생물학회지
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• 제40권3호
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• pp.221-225
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• 2004

본 논문에서는 희소 방선균, Pseudonocardia autotrophica(KCTC 9441) 유래 신규 Cytochrome P450 hydroxylase(CYP) 유전자들을 분리하여 염기서열 특성을 규명하였으며, 기존에 밝혀진 다른 방선균 유래 CYP 유전자들과의 연관성을 알아보았다. 이를 위하여 P. autotrophica의 cosmid DNA library를 제작하였고, 방선균에서 발견되는 CYP 유전자군의 보존된 서열로부터 제작된 degenerate primers를 이용한 PCR을 수행하여, P. autotrophica cosmid DNA library를 검색하였다. P. autotrophica cosmid DNA library검색 결과, P. autotrophica에는 염기서열이 서로 다른 4종의 신규 CYP유전자가 존재함이 확인되었으며 (CYP601-1, 601-2, 602, 605), 이들 신규 CYP유전자들은 방선균 유래 2차대사산물의 생합성에 관여하는 CYP유전자와 높은 유사성을 나타냈다. 특히, pESK601에서 확인된 CYP 유전자 및 주변 유전자의 염기서 열을 검색한 결과, polyene 계열의 항진균제, amphotericin과 nystatin의 생합성 유전자들과 매우 높은 유사성을 보임으로써, P. autotrophica에는 신규polyene계열의 항진균제 화합물의 생합성 유전자 군이 존재함도 규명되었다.

• Journal of Applied Biological Chemistry
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• 제62권2호
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• pp.157-165
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• 2019

Di- and tri-methylation of lysine 4 on histone H3 (H3K4me2 and H3K4me3, respectively) are epigenetic markers of active genes. Complex associated with Set1 (COMPASS) mediates these H3K4 methylations. The involvement of COMPASS activity in secondary metabolite (SM) biosynthesis was first demonstrated with an Aspergillus nidulans cclA knockout mutant. The cclA knockout induced the transcription of two cryptic SM biosynthetic gene clusters, leading to the production of the cognate SM. Monascus spp. are filamentous fungi that have been used for food fermentation in eastern Asia, and the pigment Monascus azaphione (MAz) is their main SM. Monascus highly produces MAz, implying that the cognate biosynthetic genes are highly active in transcription. In the present study, we examined how COMPASS activity modulates MAz biosynthesis by inactivating Monascus purpureus cclA (Mp-cclA) and swd1 (Mp-swd1). For both ${\Delta}Mp-cclA$ and ${\Delta}Mp-swd1$, a reduction in MAz production, accompanied by an abated cell growth, was observed. Suppression of MAz production was more effective in an agar culture than in the submerged liquid culture. The fidelity of the ${\Delta}Mp-swd1$ phenotypes was verified by restoring the WT-like phenotypes in a reversion recombinant mutant, namely, trpCp: Mp-swd1, that was generated from the ${\Delta}Mp-swd1$ mutant. Real-time quantitative Polymerase chain reaction analysis indicated that the transcription of MAz biosynthetic genes was repressed in the ${\Delta}Mp-swd1$ mutant. This study demonstrated that MAz biosynthesis is under the control of COMPASS activity and that the extent of this regulation is dependent on growth conditions.