• Mycobiology
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• 제46권3호
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• pp.269-277
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• 2018

The production of water-soluble pigments by fungal strains indigenous to South Korea was investigated to find those that are highly productive in submerged culture. Among 113 candidates, 34 strains that colored the inoculated potato dextrose agar medium were selected. They were cultured in potato dextrose broth and extracted with ethanol. The productivity, functionality (radical-scavenging activities), and color information (CIELAB values) of the pigment extracts were measured. Five species produced intense yellowish pigments, and two produced intense reddish pigments that ranked the highest in terms of absorbance units produced per day. The pigment extracts of Penicillium miczynskii, Sanghuangporus baumii, Trichoderma sp. 1, and Trichoderma afroharzianum exhibited high radical-scavenging activity. However, the S. baumii extract showed moderate toxicity in the acute toxicity test, which limits the industrial application of this pigment. In conclusion, P. miczynskii KUC1721, Trichoderma sp. 1 KUC1716, and T. afroharzianum KUC21213 were the best fungal candidates to be industrial producers of safe, functional water-soluble pigments.

• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.107-109
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• 2008

Medicinal fungi, Phellinus linteus and Inonotus xeranticus, produce a cluster of yellow pigment in their fermentation broth that acts as an important element of biological activity. The pigment is composed of diverse polyphenols with a styrylpyrone moiety, mainly hispidin and its dimers, 3,14'-bihispidinyl, hypholomine B, and 1,1-distyrylpyrylethan. Although dimeric hispidins were proposed to be biosynthesized from two molecules of monomer via oxidative coupling by ligninolytic enzymes, laccase and peroxidase, the details of this process remain unknown. In this preliminary study, we attempted to achieve enzymatic synthesis of the hispidin dimer from hispidin by using commercially available horseradish peroxidase (HRP). Consequently, a hispidin dimer, 3,14'-bihispidinyl, was synthesized, whereas the other dimers, hypholomine B and 1,1-distyrylpyrylethan, were not produced. This result suggested that the oxidative coupling at the C-3 and C-14' positions of hispidins was dominant in the process of dimerization by HRP, and indicated that additional catalysts or substrates would be needed to synthesize other hispidin dimers present in the fungal metabolite.

• Journal of Microbiology and Biotechnology
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• 제25권10호
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• pp.1648-1652
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• 2015

Azaphilone polyketides are synthesized by iterative non-reducing fungal polyketide synthases (NR-fPKSs) with a C-terminus reductive domain (-R). Several azaphilone biosynthetic gene clusters contain a putative serine hydrolase gene; the Monascus azaphilone pigment (MAzP) gene cluster harbors mppD. The MAzP productivity was significantly reduced by a knockout of mppD, and the MAzP NR-fPKS-R gene (MpPKS5) generated its product in yeast only when co-expressed with mppD. Site-directed mutations of mppD for conserved Ser/Asp/His residues abolished the product formation from the MpPKS5/mppD co-expression. MppD and its homologs are thus proposed as a new protein factor involved in the product formation of NR-fPKS-R.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.321-324
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• 2000

Monascus purpureus ATCC 16365에 의한 5-liter 배양기에서 pH 조절을 통하여 세포외로 이차대사물인 수용성 적색소의 생산 증가 현상 와 황색소 보다 적색소로의 대사과정을 촉진시켜 적색소의 생산성을 향상시킬수 있는지의 가능성에 대하여 실험을 수행하였다. 황색소와 적색소의 분석은 UV-Vis spectrophotometer를 이용하여 각각 385nm 와 495nm에서 측정하였다. 실험결과 곰팡이의 최대균체량과 황${\cdot}$적색소를 포함한 총 색소 생산양은 pH 8보다 pH 4.0-5.5인 산성조건에서 2배 및 4배정도 증가하였다. 적색소 및 황색소의 전구물질인 홍색소는 pH 4.0에서 많이 생성되며 또한 홍색소에서 적색소로의 대사과정도 산성 조건 하에서 촉진된다고 보고되었다. 본 실험에서도 같은 경향을 보였으며 또한, 산성 조건 하에서 특히 수용성 적색소가 곰팡이 세포 외로 유출되는 양이 증가하는 경향을 나타내었다.

• Mycobiology
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• 제46권4호
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• pp.429-439
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• 2018

To develop a convenient promoter analysis system for fungi, a null-pigment mutant (NPG) of Aspergillus nidulans was used with the 4'-phosphopantetheinyl transferase (PPTase) gene, npgA, which restores the normal pigmentation in A. nidulans, as a new reporter gene. The functional organization of serially deleted promoter regions of the A. nidulans trpC gene and the Cryphonectria parasitica crp gene in filamentous fungi was representatively investigated to establish a novel fungal promoter assay system that depends on color complementation of the NPG mutant with the PPTase npgA gene. Several promoter regions of the trpC and crp genes were fused to the npgA gene containing the 1,034-bp open reading frame and the 966-bp 3' downstream region from the TAA, and the constructed fusions were introduced into the NPG mutant in A. nidulans to evaluate color recovery due to the transcriptional activity of the sequence elements. Serial deletion of the trpC and crp promoter regions in this PPTase reporter assay system reaffirmed results in previous reports by using the fungal transformation step without a laborious verification process. This approach suggests a more rapid and convenient system than conventional analyses for fungal gene expression studies.

• 한국균학회지
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• 제18권4호
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• pp.181-190
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• 1990

The growth and biochemical activities of Chlorella fusca were studied in the presence of different concentrations of either filtrates or mycelial mats of Saprolegnia ferax and Pythium graminicola. Low concentrations of both fungal filtrates exerted increase in total count, dry weight and in the biosynthesis of photosynthetic pigments, carbohydrates and nitrogen content. High concentrations showed inhibitory effect on both growth and biochemical activities of Chlorella fusca. Supplementation with different concentrations of dry mycelial mats of either fungi the culture of Chlorella showed elevation in biomass, dry weight, and biosynthesis of carbohydrates and nitrogen content especially at low concentrations. The contents of photosynthetic pigment were inhibited only at low concentrations. Neither the culture filtrate of Pythium nor Saprolegnia had cellulolytic activity, although polygalacturonase enzymes were detected, whereas chloroform-extract of both fungal filtrates showed blue spots under long wave light (366 nm).

• Mycobiology
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• 제30권4호
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• pp.233-239
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• 2002

The main aim of this study is to evaluate the efficiency of two biologically active compounds(Strom and F-760) in control of wheat root rot disease and its causal organisms. Fusarium graminearum, F. oxysporum, F. solani and Bipolaris sorokiniana were used as target organisms. In vitro, the two compounds showed fungicidal effect on all investigated pathogens resulted in suppression of radial growth and mycelial dry weight of them. Under greenhouse conditions, treatment of wheat grains with either Strom or F-760 before cultivation significantly reduced the percent of disease distribution as well as the mean disease rating of plants in both seedling and flowering stages. Fresh and dry weights of plants as well as water maintenance capacity were increased as the result of applying these compounds as seed dressing. Also data showed that the membrane stability of plants was injured as a result of infection with all investigated organisms, while this injury was alleviated when F-760 and Strom were applied. The $K^+$ efflux and the leakage of UV absorbing metabolites was stimulated with fungal infection. However, F-760 and Storm treatment partially retarded the stimulatory effect on leakage of $K^+$ and UV-absorbing metabolites of fungal infected plants. On the other side, the fungal infection had inhibitory effects on pigment fractions(chlorophyll a, b, and carotenoids) biosynthesis in wheat leaves. This retarding effect was partially or completely alleviated as the grains were treated with the applied compounds.

• Molecules and Cells
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• 제38권12호
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• pp.1105-1110
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• 2015

Phleichrome, a pigment produced by the phytopathogenic fungus Cladosporium phlei, is a fungal perylenequinone whose photodynamic activity has been studied intensively. To determine the biological function of phleichrome and to engineer a strain with enhanced production of phleichrome, we identified the gene responsible for the synthesis of phleichrome. Structural comparison of phleichrome with other fungal perylenequinones suggested that phleichrome is synthesized via polyketide pathway. We recently identified four different polyketide synthase (PKS) genes encompassing three major clades of fungal PKSs that differ with respect to reducing conditions for the polyketide product. Based on in silico analysis of cloned genes, we hypothesized that the non-reducing PKS gene, Cppks1, is involved in phleichrome biosynthesis. Increased accumulation of Cppks1 transcript was observed in response to supplementation with the application of synthetic inducer cyclo-(${_L}-Pro-{_L}-Phe$). In addition, heterologous expression of the Cppks1 gene in Cryphonectria parasitica resulted in the production of phleichrome. These results provide convincing evidence that the Cppks1 gene is responsible for the biosynthesis of phleichrome.

• 한국미생물·생명공학회지
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• 제52권3호
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• pp.314-324
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• 2024

Due to the hazardous effects of synthetic pigments, natural pigments are gaining popularity. Among natural sources microorganisms have become a major source of numerous industrially essential items and their use for getting various natural products have expanded dramatically in recent years. In the present study, 9 endophytic fungal strains were isolated from Tagetes erecta. On screening, yeast strain MGI was selected for further study which was identified as Rhodotorula mucilaginosa MGI. The pigment was intracellular, and the color of the crude extract was orange. The extract was subjected to characterization by UV-visible spectrophotometer and was purified by column phase chromatography, after purification two pigmented fractions were obtained. These fractions on characterization by thin layer chromatography (TLC) and Fourier transform infrared (FTIR) spectrophotometer affirms that they belong to carotenoid group of pigments. Orange (F1) and yellow (F2) fractions were anticipated as astaxanthin and beta carotene respectively. Moreover, the bioactive potential of pigmented fractions was investigated which manifested that F1 exhibited a maximum antioxidant activity of about 77% and F2 showed the highest zone of inhibition of 38 mm against Staphylococcus aureus. Thus, this study reflects that an endophytic yeast strain has the potential for the production of bioactive microbial pigments.

• Journal of Microbiology and Biotechnology
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• 제29권8호
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• pp.1204-1211
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• 2019

Fungal exopolysaccharides are important natural products having diverse biological functions. In this study, exopolysaccharides from Fomitopsis castanea mycelia (FEPS) were prepared, and the highest mushroom tyrosinase inhibitory activity was found. FEPS were prepared from cultivation broth by ethanol precipitation method. The extraction yield and protein concentration of FEPS were 213.1 mg/l and 0.03%, respectively. FEPS inhibited mushroom tyrosinase with the half maximal inhibitory concentration ($IC_{50}$) of 16.5 mg/ml and dose-dependently inhibited cellular tyrosinase activity (63.9% at $50{\mu}g/ml$, and 83.3% at $100{\mu}g/ml$) in the cell-free extract of SK-MEL-5 human melanoma cell and ${\alpha}$-melanocyte-stimulating hormone (${\alpha}-MSH$)-stimulated melanin formation in intact SK-MEL-5 human melanoma cell. The $IC_{50}$ of FEPS against NO production from RAW264.7 macrophage cells was $42.8{\pm}0.64{\mu}g/ml$. By in vivo study using a zebrafish model, exposure of FEPS at $400{\mu}g/ml$ to dechorionated zebrafish embryos for 18 h decreased the pigment density, compared to that without FEPS-treated control.