• Korean Journal of Microbiology
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• v.38 no.1
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• pp.54-56
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• 2002

Induction of laccase isozymes under acidic stresses were determined in Trametes versicolor, Pleurotus ostreatus and Ganoderma lucidum isolated in Korea, and in Lentinus squarrosulrs isolated in Thai. When cultures of these fungi were transferred to acidic liquid media (pH 3.0-4.0), the activities of secreted extralcellular laccases were increased 60% and 400% in T. versicolor and G. lucidum respectively. However, there was no such induction in L. squarrosulus or P. ostreatus. In L. squarrosulus, different laccase isozymes in the electrophoretic mobilities were induced under acidic conditions.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.230.3-231
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• 2000

No Abstract, See Full Text

• Korean Journal of Pharmacognosy
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• v.24 no.2
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• pp.116-123
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• 1993

The genus Ganoderma is typical wood-rotting fungi and its fruiting body has been used as an important herb in oriental medicine. Recent research discovered antitumor components from Ganoderma lncidum. Various Ganoderma species are being cultivated in Korea. However, taxonomic system of the genus Ganoderma has been based mainly on the macromorphology of fruiting bodies and the ultrastructural characteristics of basidiospores. Since there are similar characteristics in Ganoderma mycelia grown on the same artificial media, it is suggested that the compatibility of the fungi by di-mon mating be used as an aid to determine the identity of species in addition to the conventional characterization. In this study, we examined physiological and genetical properties such as growth temperature, pH, compatibility and enzyme or protein patterns of laccase, esterase and cellular proteins of G. lucidum RZ, G. tsugae and Ganoderma species cultivated in Korea by electrophoresis for characterization of the isolates. We found that compatibility test and isozyme patterns of laccase and esterase of the mycelia could be used for the differentiation of the isolates. These results showed that Ganoderma species cultivated in Korea is genetically similar to G. lucidum but physiologically closer to G. tsugae than to G. lucidum.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.249-253
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• 2016

The inky cap, Coprinellus congregatus, produces several laccase isozymes during its life cycle: both hyphal tip laccase and sclerotial laccase are involved in the fungal development. When this fungus was transferred to an acid liquid medium (pH 4.0-4.5), a new laccase was synthesized and secreted into the culture supernatant. In order to examine its regulation by external pH, green fluorescent protein gene was ligated at the downstream of the promoters having different lengths. These expression vectors having different promoter lengths were inserted into the fungal transformation vector, pBARGEM7-1. These expression vectors were introduced to the mating type a1 and a2 monokaryons, and the transformants were selected by the phosphinothricin resistance. Transformant a1 (a1TF) and transformant a2 (a2TF) were mated with each other to generate homozygotic dikaryon transformants. All these transformants were grown in neutral liquid medium for 5 days, and then the whole cell homogenates were transferred to the acidic liquid medium (pH 4.1). After 36 h incubation at $25^{\circ}C$, cells were harvested for the analysis of GFP expression. GFP expression was detected in the transformant having full-length promoter (2.0 kb), but other transformants having shorter length promoter (shorter than 1.29 kb) failed to show the fluorescence. Therefore, the acid-responsive element in the laccase promoter should be localized between -2.0 kb ~ -1.29 kb region.

• Mycobiology
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• v.43 no.3
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• pp.280-287
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• 2015

In this study, transcriptome analysis of twelve laccase genes in Pleurotus ostreatus revealed that their expression was differentially regulated at different developmental stages. Lacc5 and Lacc12 were specifically expressed in fruiting bodies and primordia, respectively, whereas Lacc6 was expressed at all developmental stages. Lacc1 and Lacc3 were specific to the mycelial stage in solid medium. In order to investigate their biochemical characteristics, these laccases were heterologously expressed in Pichia pastoris using the pPICHOLI-2 expression vector. Expression of the laccases was facilitated by intermittent addition of methanol as an inducer and sole carbon source, in order to reduce the toxic effects associated with high methanol concentration. The highest expression was observed when the recombinant yeast cells were grown for 5 days at $15^{\circ}C$ with intermittent addition of 1% methanol at a 12-hr interval. Investigation of enzyme kinetics using 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) as a substrate revealed that the primordium-specific laccase Lacc12 was 5.4-fold less active than Lacc6 at low substrate concentration with respect to ABTS oxidation activity. The optimal pH and temperature of Lacc12 were 0.5 pH units and $5^{\circ}C$higher than those of Lacc6. Lacc12 showed maximal activity at pH 3.5 and $50^{\circ}C$, which may reflect the physiological conditions at the primordiation stage.