• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.4
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• pp.278-286
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• 1987

The results in vestigated produced fluorescence compounds and mycotoxins, studied stability and toxicity of these compounds which were isolated from varicous moistured rice culture extacts inoculated Aspergillus versicolor IFO 30338, 10 kinds of fluorescence compounds were isolated. Sterigmatocystin was produced $38{\mu}g/kg$ in 16%, $329{\mu}g/kg$ in 25% and $380{\mu}g/kg$ in 35% moistured rice 20 days culture respectively. Aflatoxin $B_1$ was produced $3{\mu}g/kg$ in 25% and $12.6{\mu}g/kg$ in 35% moistured rice 20 days culture. In embryo test of isolated fraction 2, 4 and 6 by T.L.C., $LD_{50}$ of fraction 2 was $40{\mu}g/egg$ and fraction 4,6 was $60{\mu}g/egg$, and these compounds were mostly decomposed and fraction 4 and 6 were partly changed into fraction 2 below pH 2 and above pH 10. fraction 2,4 and 6 were all stable when treated 60 min, at $100^{\circ}C$, but were decomposed $60{\sim}65%$ when treated 60 min at $150^{\circ}C$, $95{\sim}100%$ when treated 10 min at $200^{\circ}C$.

• Journal of Microbiology
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• v.44 no.2
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• pp.145-154
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• 2006

Heterotrimeric G proteins (G proteins) are conserved in all eukaryotes and are crucial components sensing and relaying external cues into the cells to elicit appropriate physiological and biochemical responses. Basic units of the heterotrimeric G protein signaling system include a G protein-coupled receptor (GPCR), a G protein composed of ${\alpha},\;{\beta},\;and\;{\gamma}$ subunits, and variety of effectors. Sequential sensitization and activation of these G protein elements translates external signals into gene expression changes, resulting in appropriate cellular behaviors. Regulators of G protein signaling (RGSs) constitute a crucial element of appropriate control of the intensity and duration of G protein signaling. For the past decade, G protein signaling and its regulation have been intensively studied in a number of model and/or pathogenic fungi and outcomes of the studies provided better understanding on the upstream regulation of vegetative growth, mating, development, virulence/pathogenicity establishment, and biosynthesis of secondary metabolites in fungi. This review focuses on the characteristics of the basic upstream G protein components and RGS proteins, and their roles controlling various aspects of biological processes in the model filamentous ascomycete fungus Aspergillus nidulans. In particular, their functions in controlling hyphal proliferation, asexual spore formation, sexual fruiting, and the mycotoxin sterigmatocystin production are discussed.

• The Korean Journal of Mycology
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• v.43 no.3
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• pp.149-157
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• 2015

We examined taxonomic characteristics and safety of eight Nuruk molds that are widely used for making soybean paste, soy sauce and alcoholic beverages in Korea. HK1 from Hakyeong Fermentation Co., SW101 from Suwon Fermentation Co., CF1001, CF1002, CF1003 from Chungmoo Fermaentation Co. and KACC 93210 are yellow-Nuruk molds, and SW201 from Suwon Fermentation Co. and CF1005 from Chungmoo Fermentation Co. are white-Nuruk molds. Six strains of yellow-Nuruk molds were identified as Aspergillus oryzae. HK1, SW101, CF1001 and CF1003 of yellow-Nuruk molds have middle length of stipes ($711{\sim}1,121{\mu}m$), and CF1003 (for sake) produced less conidia and more hyphae than HK1, SW101 and CF1001 (for soybean paste). CF 1002 used for soy sauce has shorter stipes ($543{\mu}m$) and is clustered into IBLB-group based on omtA gene analysis although the other yellow-Nuruk molds are clustered into ICAo group. KACC 93210 isolated from traditional Korean Meju has very short stipes (average $270{\mu}m$), and showed velvety colonies although the others showed floccose colonies. The strain has different DNA sequences of omtA gene from other strains in NCBI GenBank as well as strains used in Korea, suggesting that it is unique from other strains published. SW201 and CF1005 of white-Nuruk molds were identified as Aspergillus luchuensis or A. luchuensis mut. Kawachii that is known as safe, non-toxigenic fungus. The six strains of yellow-Nuruk molds did not produce mycotoxins including aflatoxin, cyclopiazonic acid, and sterigmatocystin. Therefore, eight strains of Nuruk molds used for making soy sauce, soybean paste and alcoholic beverages in Korea were proved to be safe in this study.