• Journal of Microbiology and Biotechnology
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• 제16권3호
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• pp.450-456
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• 2006

Pseudomonas fluorescens MC07 is a growth-promoting rhizobacterium that suppresses mycelial growth in fungi such as Rhizoctonia solani, Pythium ultimum, Fusarium oxysporum, and Phytophthora capsici. To determine the role of the bacterium's antifungal activity in disease suppression, we screened 2,500 colonies generated by Tn5lacZ insertions, and isolated a mutant 157 that had lost antifungal activity. The EcoRI fragment carrying Tn5lacZ was cloned into pBluescript II SK(+) and used as a probe to isolate wild-type clones from a genomic library of the parent strain, MC07. Two overlapping cosmid clones, pEH4 and pEH5, that had hybridized with the mutant clone were isolated. pEH4 conferred antifungal activity to the heterologous host P.fluorescens strain 1855.344, whereas pEH5 did not. Through transposon mutagenesis of pEH4 and complementation analyses, we delineated the 14.7-kb DNA region that is responsible for the biosynthesis of an antifungal compound. DNA sequence analysis of the region identified 11 possible open reading frames (ORF), ORF1 through ORF11. A BLAST search of each putative protein implied that the proteins may be involved in an antifungal activity similar to polyketides.

• Journal of Applied Biological Chemistry
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• 제52권4호
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• pp.221-225
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• 2009

Lithospermum erythrorhizon has been known well as one of traditional medicine for fever reduction, detoxication, and blood circulation improvement. This study was carried out to isolate biological active compounds from roots of Lithospermum erythrorhizon and to investigate their low density lipoprotein (LDL) antioxidant and anticancer activities. The hexane extract of Lithospermi Radix has been separated on silica gel chromatography and a naphthoquinone pigment compound 1 has been isolated. The structure of the compound 1 has been identified by spectroscopic technique, including MS and NMR, as acetylshikonin (1). Acetylshikonin showed significantly inhibitory activity on $Cu^{2+}$-induced human LDL oxidation with $IC_{50}$ value of $8.8\;{\mu}M$ and obvious anticancer effect by inhibiting farnesyl:protein transferase (FPTase) activity with $IC_{50}$ value of $23\;{\mu}M$, which suggested that acetylshikonin might be useful for the treatment of atherosclerosis and cancer.

• Journal of Microbiology and Biotechnology
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• 제16권6호
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• pp.952-960
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• 2006

As a unicellular green alga that possesses many of the metabolic pathways present in higher plants, Chlorelia offers many advantages for expression of heterologous proteins. Since strong and constitutive promoters are necessary for efficient expression in heterologous expression systems, the development of such promoters for use in the Chlorella system was the aim of this study. Proteins encoded by the early genes of algal viruses are expressed before viral replication, probably by the host transcriptional machinery, and the promoters of these genes might be useful for heterologous expression in Chlorella. In this study, putative promoter regions of DNA polymerase, ATP-dependent DNA ligase, and chitinase genes were amplified from eight Korean Chlorella virus isolates by using primer sets designed based on the sequence of the genome of PBCV-1, the prototype of the Phycodnaviridae. These putative promoter regions were found to contain several cis-acting elements for transcription factors, including the TATA, CAAT, NTBBF1, GATA, and CCAAT boxes. The amplified promoter regions were placed into Chlorella transformation vectors containing a green fluorescence protein (GFP) reporter gene and the Sh ble gene for phleomycin resistance. C. vulgaris protoplasts were transformed and then selected with phleomycin. The GFP fluorescence intensities of cells transformed with chitinase, DNA polymerase, and DNA ligase gene promoter-GFP fusion constructs were 101.5, 100.8, and 95.8%, respectively, of that of CaMV 35S-GFP-transformed Chlorella cells. These results demonstrate that these viral promoters are active in transformed Chlorella.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.151-156
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• 2003

토양으로부터 세포외로 $\beta$-galactosidase를 분비 생산하는 방선균 YB-10이 분리되었으며, 분리균의 배양ㆍ형태ㆍ생리적 특성을 조사한 결과 Streptomyces속 균주로 확인되었다. 분리균의 배양상등액을 30%~70% ammonium sulfate로 처리하고 투석하여 얻은 $\beta$-galactosidase를 조효소액으로 사용하였을 때 para-nitrophenyl-$\beta$-D-galactopyranoside (pUP$\beta$Gal)는 pH 6.0과 6$0^{\circ}C$의 반응조건에서 가장 잘 분해되었으며, lactose는 galactose와 glucose로 가수분해되는 것으로 확인되었다. 분리균이 생산하는 $\beta$-galactosidase는 galactose에 의해 lactose와 pNP-$\beta$Gal의 가수분해 활성이 모두 저해되었으나, glucose에 의해서는 lactos의 가수분해 활성만 저해되었다. 특히 pUP-$\beta$Gal의 가수분해 활성은 glucose에 의해 약 1.8배 증진되었다.

• 한국미생물·생명공학회지
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• 제40권4호
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• pp.303-309
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• 2012

Keratinases are of particular interest because of their action on insoluble keratins and generally on a broad range of protein substrates. Alkalophilic and neutrophilic actinomycete strains isolated from different soil samples, rich in keratinaceous substances were screened for keratinolytic activity. An alkalophilic isolate, TBG-S13A5, was found to possess good keratinolytic activity and was able to utilize feather as the sole carbon and nitrogen source. TBG-S13A5 exhibited an off-white aerial mass color with a rectus-flexibilis type of spore chain. The morphological, microscopical and biochemical characters were comparable with that of Streptomyces albidoflavus. Fatty acid methyl ester profiling (FAME) and 16S rDNA sequence analysis confirmed its identity as a strain of S. albidoflavus. Under submerged fermentation conditions, maximum protease production was recorded on the $5^{th}$ day of incubation at $30^{\circ}C$, using basal broth of pH 9.0 with 0.25% (w/v) white chicken feather. This strain could affect feather degradation when the initial pH was 8 and above and maximum protease production was recorded when the initial pH was around 10.5. The effectiveness of the crude enzyme in destaining and leather dehairing were also demonstrated.

• 한국식품저장유통학회지
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• 제12권5호
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• pp.460-464
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• 2005

콩 가수분해물의 기능성 강화를 위하여 콩분말 및 SPI에 4종의 protease를 처리하여 가수분해물의 특성을 조사하였다. 수율은 protease(B)를 처리하였을 때 콩분말에서 43.2%, SPI에서 61.6%로 가장 높게 나타났다. 용해도와 총페놀성 물질은 protease(B)와 (C)처리구에서 크게 증가하였으며, 칼슘내인성은 protease(B)를 처리하였을 때 향상되었다. 콩분말에서 콩 특유의 비린내는 protease처리로 감소하였으나 콩분말과 SPI 모두 protease 처리로 쓴맛이 강해졌으며 protease의 종류에 따른 차이는 확인되지 않았다. 가수분해물의 수율을 비롯한 이화학적 특성을 감안할 때, protease (B)가 가수분해물 제조에 적합하였으며, 가수분해물의 활용 형태에 따라 관능적 특성의 보완이 요구되었다.

• 식물병연구
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• 제22권1호
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• pp.55-58
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• 2016

고추포장 주변의 모자이크 및 기형의 병징을 보이는 토끼풀에서 CMV를 분리하여 CMV-Tr1으로 명명하였다. 토끼풀로부터 RT-PCR, PCR-restriction fragment length polymorphism 및 외피단백질 유전자의 염기서열 분석을 통해 CMV를 동정하였다. 기주식물 반응결과 N. benthamiana를 포함한 5종의 담배와 오이, 꽈리 및 토마토의 상엽에서 모자이크 병징을 나타내었고, 명아주와 동부에서는 접종엽에 국부괴사 병반을 나타냈다. CMV-Tr1의 외피단백질을 CMV-As와 비교한 결과 99.5%의 상동성을 보였으며, 계통분석 결과 CMV subgroup IB에 속하는 CMV의 한 계통으로 확인되었다.

• The Plant Pathology Journal
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• 제33권3호
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• pp.318-328
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• 2017

Chitinase-producing Paenibacillus elgii strain HOA73 has been used to control plant diseases. However, the antimicrobial activity of its extracellular chitinase has not been fully elucidated. The major extracellular chitinase gene (PeChi68) from strain HOA73 was cloned and expressed in Escherichia coli in this study. This gene had an open reading frame of 2,028 bp, encoding a protein of 675 amino acid residues containing a secretion signal peptide, a chitin-binding domain, two fibronectin type III domains, and a catalytic hydrolase domain. The chitinase (PeChi68) purified from recombinant E. coli exhibited a molecular mass of approximately 68 kDa on SDS-PAGE. Biochemical analysis indicated that optimum temperature for the actitvity of purified chitinase was $50^{\circ}C$. However, it was inactivated with time when it was incubated at $40^{\circ}C$ and $50^{\circ}C$. Its optimum activity was found at pH 7, although its activity was stable when incubated between pH 3 and pH 11. Heavy metals inhibited this chitinase. This purified chitinase completely inhibited spore germination of two Cladosporium isolates and partially inhibited germination of Botrytis cinerea spores. However, it had no effect on the spores of a Colletotricum isolate. These results indicate that the extracellular chitinase produced by P. elgii HOA73 might have function in limiting spore germination of certain fungal pathogens.

• 대한미생물학회지
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• 제35권3호
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• pp.215-224
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• 2000

In this study, the distribution of the mec regulator genes and the presence of the mutation in mecI gene and mec promoter region among 50 MRSA clinical isolates derived from a single university hospital in Korea were analyzed. Among 50 MRSA strains, 13 strains had a deletion of mecI gene, and 37 strains were found to have mutations in mecI gene or mecA promoter region corresponding to a presumptive operator of mecA, i.e., the binding site of the repressor protein. Furthermore, in order to track the evolution of methicillin-resistant Staphylococcus aureus (MRSA) distributed in Korea, we determined the MRSA clonotype by combined use of genetic organization patterns of mec regulator genes, ribotype, and coagulase type. As the result, 48 of 50 MRSA strains could be classified into four distinct clones. Clonotype I is characterized by the coagulase type 3, deletion of mecI gene, and ribotype 1 shared by NCTC10442, the first reported MRSA isolate in England (9 strains). Clonotype II is characterized by the coagulase type 4, C to T substitution at position 202 of mecI gene, and ribotypes 2, 3 and 4 shared by 85/3619 strain isolated in Austria (10 strains). Clonotype III is characterized by the coagulase type 2, mutations of mecA promoter region and/or mecI, and ribotypes 4, 5, and 6 shared by N315 strain isolated in Japan (25 strains). Clonotype IV is characterized by the coagulase type 4, deletion of mecI gene, and ribotype 7 (4 strains). The clonality of two strains could not be determined due to their undefined ribotype.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1591-1598
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• 2004

To isolate the $\beta$-galactosidase producing thermophilic bacteria, samples of mud and water were collected from hot springs of avolcanic area near Golden Springs in New Zealand. Among eleven isolated strains, the strain of KNOUC112 produced the highest amounts of $\beta$-galactosidase at 40 h incubation time (0.013 unit). This strain was aerobic, asporogenic bacilli, immobile, gram negative, catalase positive, oxidase positive, and pigment producing. Optimum growth was at 70-72$^{\circ}C$, pH 7.0-7.2, and it could grow in the presence of 3% NaCl. The main fatty acids of cell components were iso-15:0 (30.26%), and iso-17:0 (31.31%). Based on morphological and biochemical properties and fatty acid composition, the strain could be identified as genus Thermus, and finally as Thermus thermophilus by phylogenetic analysis based on 16S rRNA sequence. So the strain is designated as Thermus thermophilus KNOUC112. A gene from Thermus thermophilus KNOUC112 encoding $\beta$-galactosidase was amplified by PCR using redundancy primers prepared based on the structure of $\beta$-galactosidase gene of Thermus sp. A4 and Thermus sp. strain T2, cloned and expressed in E. coli JM109 DE3. The gene of Thermus thermophilus KNOUC112 $\beta$-galactosidase(KNOUC112$\beta$-gal) consisted of a 1,938 bp open reading frame, encoding a protein of 73 kDa that was composed of 645 amino acids. KNOUC112$\beta$-gal was expressed as dimer and trimer in E. coli JM109 (DE3) via pET-5b.