• Journal of Microbiology
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• v.43 no.3
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• pp.301-307
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• 2005

The feasibility of laccase production by immobilization of Pleurotus ostreatus 1804 on polyurethane foam (PUF) cubes with respect to media composition was studied in both batch and reactor systems. Enhanced laccase yield was evidenced due to immobilization. A relatively high maximum laccase activity of 312.6 U was observed with immobilized mycelia in shake flasks compared to the maximum laccase activity of free mycelia (272.2 U). It is evident from this study that the culture conditions studied, i.e. biomass level, pH, substrate concentration, yeast extract concentration, $Cu^{2+}$ concentration, and alcohol nature, showed significant influence on the laccase yield. Gel electrophoretic analysis showed the molecular weight of the laccase produced by immobilized P. ostreatus to be 66 kDa. The laccase yield was significantly higher and more rapid in the packed bed reactor than in the shake flask experiments. A maximum laccase yield of 392.9 U was observed within 144 h of the fermentation period with complete glucose depletion.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.37-41
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• 2001

Two linear plasmid-like DNAs, 10.2 kb and 7.2 kb were found in the mitochondria of P. ostreatus. They have covalently linked 5'-terminal proteins in both ends. Two continuous fragments of 4.7 kb and 2.3 kb from 7.2 kb DNA were cloned and sequenced. Two long open reading frames (ORF1; 2982 bp, 993 a.a and ORF2; 2703 bp, 900 a.a) and one short open reading frame(ORF3; 771 bp, 256 a.a) were found in the 7.2 kb plasmid. The putative ORF1 and ORF2 have conserved motifs of DNA polymerases and RNA polymerases, respectively, while the ORF3 has homologous regions with phosphatase from Plasmodium, and also with adhesine from Mycoplasma.

• Journal of Microbiology
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• v.37 no.4
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• pp.229-233
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• 1999

The mitochondrial plasmid pMLP1 from a white-rot fungus, Pleurotus ostreatus, is a double-stranded DNA containing 381 bp terminal inverted repeat (TIR) whose 5'-ends are covalently bound by terminal proteins. The plasmid contains two major open reading frames (ORFs), encoding putative DNA and RNA polymerases, and a minor ORF encoding a small, highly basic protein. To identify the DNA binding activity that recognizes the TIR region of pMLP1, gel retardation assays were performed with mitochondrial extracts. A specific protein binding to a region between 123 and 248 nt within TIR was observed. We examined whether the gene product of mORF1 bindes to this region specifically. E. coli cell extract which contains an overproduced mORF1 protein formed a complex specific to the region between 123 and 248 nt. Inclusion of mORF1 protein in the specific complex formed between P. ostreatus mitochondrial extract and TIR was confirmed by a supershift assay using polyclonal antibodies against the mORF1 protein. Our result suggest that the product of mORF1 may function as a terminal region recognition factor (TRF), recognizing an internal region in TIR.

• Mycobiology
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• v.47 no.1
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• pp.97-104
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• 2019

Mushroom cultivation has gained increased attention in recent years. Currently, only four types of spawn, including sawdust spawn, grain spawn, liquid spawn, and stick spawn, are commonly available for mushroom cultivation. This limited spawn diversity has led to difficulty in selecting suitable inoculum materials in some cultivation. In this study, three small blocks of lignocellulosic agro-wastes and one block of a synthetic matrix were prepared as support for growing Pleurotus ostreatus in liquid medium. Mycelium-adsorbed blocks were then evaluated for their potential as block spawn for fructification. Our results indicated that the edible fungus was adsorbed and abundantly grew internally and externally on loofah sponge and synthetic polyurethane foam (PUF) supports and also has the ability to attach and grow on the surface of sugarcane bagasse and corncob supports. The mycelia of P. ostreatus adhered on corncob exhibited the highest metabolic activity, while those on the PUF showed the least activity. Mycelial extension rates of block spawns made of agro-waste materials were comparable to that of sawdust spawn, but the block spawn of PUF showed a significantly lower rate. No significant differences in cropping time and yield were observed among cultivations between experimental block spawns and sawdust spawns. Moreover, the corncob block spawn maintained its fruiting potential during an examined period of 6-month storage. The developed block spawn could be practically applied in mushroom cultivation.

• The Korean Journal of Food And Nutrition
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• v.28 no.1
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• pp.60-65
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• 2015

Mushrooms (Pleurotus ostreatus) have been used as traditional remedies as well as food sources. This study particularly used an extract of Pleurotus ostreatus among many other mushrooms for research to figure out the antioxidant activity and an effect of cytotoxin. The result of antioxidative effect was significantly increased at the high concentration. The otal contents of polyphenol and flavonoid were $30.2{\pm}0.7$ and $20.4{\pm}0.6$ respectively. Both reducing power and DPPH radical scavenging activities are highest at 5.0 mg/mL of concentration. According to the research about cytotoxin of normal cell, an extract of Pleurotus ostreatus showed no existence of toxicity based on 80.5% of viability. Meanwhile, Pleurotus ostreatus is not strongly effective on the growth of cancer cell, indicating anti-cancer effect has a quite high range of viability up to $70.0{\pm}5.3%$ in 5 mg/mL of concentration.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.324-331
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• 1988

Ascorbate oxidizing enzyme from the crude extract of Pleurotus ostreatus was purified by ammonium sulfate precipitation, preparative polyacrylamide gel electrophoresis, DEAE Sepharose CL-6B ion exchange chromatography and Sephadex G-150 gel filtration chromatography. The molecular weight of the enzyme estimated by Sephadex G-150 gel filtration chromatography was 140,000 and that of its subunit by SDS-polyacrylamide gel electrophoresis 66,000. The optimum pH for the maximum activity of the enzyme was 5.2 and the isoelectric point of the enzyme was 6.0 Km values for L-ascorbic acid and D-isoascorbic acid were both 2.2.$\mu$M, which indicates that the enzyme has the asme affinity towards both substrates.

• Journal of Life Science
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• v.10 no.5
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• pp.519-523
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• 2000

The action spectrum for light-induced growth of fruit body in Pleurotus ostreatus has been studied by irradiation at various wavelengths. Effective wavelengths were distributed from near ultraviolet to blue region of spectrum. The most effect of light was observed in the region between 340 to 520 nanometers. The growth weigth obtained from which has been irradiated 144 hours in the region of 340-520 nm increases 74%, on the contrary the observed growth weight has been observed in the longer wavelengths than 620 nm. The pileus size was promoted 30$\times$32% in the region of 340-500 nm, and retarded 22$\times$19% in the dark. the strip length was rearded 12% in the region of 340-500 nm, and promoted 38% in the dark. The color thickness for pileus is getting light in longer wavelengths.

• The Korean Journal of Mycology
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• v.38 no.2
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• pp.142-145
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• 2010

In this study, we attempted to find substitute materials, swelling rice hull, cocopeat, corncob and coconut sawdust, for sawdust in bottle cultivation of Pleurotus ostreatus. Chemical characters of mixture substrates with four substitute materials for pine sawdust were not different significantly. By comparison in mycelial growth and yield of fruitbody, mixture substrate of cocopeat were showed the same level in P. ostreatus. Therefore, it is suggested that cocopeat was substituted for sawdust for cultivation of P. ostreatus.

• Proceedings of the Korean Biophysical Society Conference
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• 1998.06a
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• pp.25-25
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• 1998

Ascorbyl free radical reductase was purified from the white rot fungus, Pleurotus ostreatus. The enzyme contained FMN as a prosthetic group, which was reduced by NADH and reoxidized by ascorbyl free radical. Reduction of ascorbyl free radical by the enzyme was observed by EPR spectroscopy.(omitted)

• Korean journal of applied entomology
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• v.42 no.1
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• pp.71-75
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• 2003

A paedogenetic gall midge, Mycophila speyeri Barnes (Diptera: Cecidomyiidae) was newly found on the cultivated oyster mushroom, Pleurotus ostreatus Hummer in Korea. Brief morphological characteristics are described.