• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.11-16
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• 2009

Magnaporthe oryzae, the causal agent of rice blast, forms a specialized infection structure, called an appressorium, which is crucial for penetration and infection of the host plant. Pharmacological data suggest that calcium/calmodulindependent signaling is involved in appressorium formation in this fungus. To understand the role of the calcium/calmodulin-activated protein phosphatase on appressorium formation at the molecular level, MCNA, a gene encoding the catalytic subunit of calcineurin, was functionally characterized in M. oryzae. Transformants expressing sense/antisense RNA of MCNA exhibited significant reductions in mycelial growth, conidiation, appressorium formation, and pathogenicity. cDNA of MCNA functionally complemented a calcineurin disruptant strain (cmp1::LEU2 cmp2::HIS3) of Saccharomyces cerevisiae. These data suggest that calcineurin A plays important roles in signal transduction pathways involved in the infection-related morphogenesis and pathogenicity of M. oryzae.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.61-66
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• 1999

The purpose of this study was to improve the palatability of kochujang. The activities of liquefying amylase and saccharogenic amylase in Monacus anka koji were lower than those in Asp. oryzae koji. The acid protease activity(1.4 units/g) in M. anka koji was also lower than that(1.6 units/g) in Asp. oryzae koji. Glucosamine amount in Asp. oryzae koji was 1075 g, and that in M. anka koji was 318 g. Four kinds of Kochujang were prepared with Asp. oryzae koji(A), M. anka koji(M), mixed koji of Asp. oryzae and M. anka(A＋M), and mixture of M. anka koji and malt(M＋M). The pH of four kinds of kochujang was 5.1 in the beginning and was between 4.70~4.83 after 120 days of fermentation. Reducing sugar of kochujang was between 16.3~20.7% after fermentation and kochujang prepared with M＋M showed the highest reducing sugar content. Amino nitrogen of kochujang was between 182 mg%~230 mg% after fermentation and the highest amino nitrogen content was observed at kochujang prepared with A＋M. Kochujang prepared with M and M＋M showed higher a value than kochujang prepared with A and A＋M.

• YAKHAK HOEJI
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• v.44 no.2
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• pp.197-203
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• 2000

The enzymatic properties of $\beta$-galactosidases from Aspergillus oryzae, bovine liver and Saccharomyces pragilis have been studied using enzyme-linked lectin assay based on the RC $A_{120}$ and BS-II lectins which specifically bind to terminal galactose and GlcNAc residue, respectively. Asialofetuin, a monomeric glycoprotein with approximately 48 kDa in molecular weight, was used as a substrate. This glycoprotein contains three N-linked triantennary complex type carbohydrate chains with each of which terminating in Ga1$\beta$P1 longrightarrow4G1cNAc (74%). Their optimal pHs were 3.5 and 6.5 (A. oryzae), and 3.5~5.5 (bovine liver and S. fragilis) at 37$^{\circ}C$ during 24 hrs, and the effective concentrations were 0.9, 2.9, and 1.7 mg/ml, respectively The enzyme from A oryzae requires 100 mM N $a^{+}$ or $K^{+}$, while the enzyme from bovine liver requires $Ba^{2+}$ for activity. However all of the three $\beta$-galactosidases were inactivated by SDS and C $u^{2+}$. These results indicate that the hydrolysis of glycoprotein such as asialofetuin depends on the reaction conditions of $\beta$-galactosidases and some metal ions. ions.

• Archives of Pharmacal Research
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• v.27 no.6
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• pp.624-627
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• 2004

A bile acid derivative, methyl chalate （1）, was isolated from EtOAc extract of the fungus Rhizopus oryzae as a cholesterol biosynthesis inhibitor. It showed moderate inhibitory activity on cholesterol biosynthesis in human Chang liver cells. Compound 1 exhibited inhibitory effect on the later step of cholesterol biosynthesis, indicating that its action mode is different from that of statins that act on the HMG-CoA reductase.

• Journal of Plant Biotechnology
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• v.43 no.4
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• pp.422-431
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• 2016

Plants utilize cytochrome P450, a large superfamily of heme-containing mono-oxygenases, in the synthesis of lignins, UV protectants, pigments, defense compounds, fatty acids, hormones, and signaling molecules. Despite the overwhelming assortment of rice P450 accession numbers in the database, their functional studies are lacking. So far, there is no evidence involving rice P450 in disease immunity. Most of our understanding has been based on other plant systems that are mostly dicot. In this study, we isolated the cytochrome P450 (OsCYP71) in rice, and screened the gene using gain-of-function technique. The full-length cDNA of OsCYP71 was constitutively overexpressed using the 35S promoter. We then explored the functions of OsCYP71 in the rice - Xanthomonas oryzae pv. oryzae pathosystem. Using the gene expression assays, we demonstrate the interesting correlation of PR gene activation and the magnitude of resistance in P450-mediated immunity.

• The Korean Journal of Mycology
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• v.42 no.3
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• pp.191-200
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• 2014

Nuruk samples collected from various regions in Korea were investigated in terms of fungal contents and diversity. In measurement of colony forming unit (CFU) in Nuruk suspensions on DRBC agar, Nuruk samples MS4, MS8, and MS10 were among the highest fungal density, with $1,278.9{\pm}21.6$ (${\times}10^4$), $1,868.0{\pm}27.7$ (${\times}10^4$), and $775.1{\pm}19.2$ (${\times}10^4$) were among the samples showing the highest fungal density. CFU per 20 mg Nuruk, respectively. The majority of fungal components were yeasts, including Pichia anomala, P. kudriavzevii, Kluyveromyces marxianus, and Saccharomycopsis fibuligera, whereas Aspergillus oryzae and Rhizopus oryzae, the representative Nuruk fungi, were predominant only in the low fungal density Nuruks (MS2, MS5, and MS11). Saccharification capability of the fungal isolates was assessed by measurement of amylase activity in the culture broth. The highest amylase activity was found in A. niger and A. luchuensis, followed by S. fibuligera. A. oryzae and R. oryzae showed fair amylase activity but significantly lower than those of the three fungal species. R. oryzae was suggested to play an additional role in degradation of ${\beta}$-glucan in crop component of Nuruk since R. oryzae was the only fungus that showed ${\beta}$-glucanase activity among the fungal isolates. To confirm the safety of Nuruk, aflatoxigenicity of the isolated Aspergillus was estimated using the DNA markers norB-cypA, aflR, and omtA. All of the isolates turned out to be non-aflatoxigenic as evidenced by the deletion of gene markers, norB-cypA and aflR, and the absence of aflatoxin in the culture supernatants shown by TLC analysis.

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.95-101
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• 2008

The gene encoding a putative esterase of Xanthomonas oryzae pv. oryzae was cloned using PCR technique. The gene was expressed with His6 tag in E. coli. One-step purification of the recombinant esterase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 30 kDa, as expected, therefore the enzyme was a mononer. The enzyme was the most active toward p-nitrophenyl (p-NP) acetate and p-NP-butyrate to a lesser extent. However, the enzyme could not hydrolyze p-NP-myristate, palmitate, and stearate. Therefore, the enzyme is considered as an esterase, very different from lipase. The purified esterase had optimal pH at around 8.0 and was stable in a broad range of pH values. The optimal temperature ranged from 30 to $40^{\circ}C$, and the residual activity observed after heat treatment at $55^{\circ}C$ for 20 min was 72 % of the initial activity. The activity was inhibited by the presence of copper and cobalt ions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.357-363
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• 2000

고추장의 품질을 향상시키고 재래식 전통 고추장과 유사한 맛을 지닌 고추장을 만들기 위해 재래식 전통 고추장에서 분리한 B.licheniformis 균주와 공장에서 대량 생산을 위해 개량해온 A. oryzae와, 비교적 호염성이며 알콜 발효 능력이 우수한 S.rouxii를 혼용하여 고추장을 담근 후 180일까지의 각 고추장의 이화학적 특성 변화를 조사한 결과는 다음과 같다. 단도는 모든 구에서 숙성 30일 까지 급격히 증가한 후 180일까지 거의 일정한 수준을 유지하였으며, 곰팡이 단용구에 비해 고초균과 효모 혼용구에서 숙성 기간 동안 높은 적정산도 값을 보였다. 조단백질은 숙성 기간 동안 대조구에서는 숙성 60일까지 약간 증가한 후 숙성 120일까지 급격히 감소하였으며 고초균 혼용구와 효모 첨가구는 숙성 90일 이후 감소한 후 숙성 120일 이후부터는 거의 변화가 없었다. 숙성 90일 이후부터는 B. licheniformis와 효모 혼용구에서 A. oryzae 단용구보다 조단백질 함량이 높았다. 환원당은 세 구간 모두 숙성 60일 경까지는 증가하는 추세를 보였으며, A. oryzae 단용구보다 B.licheniformis 균주와의 혼용구에서 높은 수치를 보여주었다. 비휘발성 유기산은 숙성 기간이 경과하면서 증가하였고 가장 많이 검출된 유기산은 pyroglutamic acid와 citric acid의 순이었다. 따라서 고추장의 숙성 과정 중 이화학적 특성 변화의 측면에서 볼 때 고초균과 효모 혼용구로 제조된 고추장이 구수한 맛의 생성면에서 유용한 담금법인 것으로 사료된다.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.227-232
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• 1982

The methods determining the growth rate of mold on beans were investigated in order to compare the growth of Aspergillus oryzae on lupinseed to that on soybean. The growth of A. oryzae on cooked whole or paste form of bean substrates was evaluated by the measurements of colony diameter and hyphae length of the mold. The mold showed characteristic lag times to form the colony on different types of substrate. The growth of colony diameter was coincided with the increase in $\alpha$-amino nitrogen content of the substrate when the moisture level of the substrates was similar each other. The colony diameter and the cultivation time after the lag period showed a straight line relationship, from which the growth rate was estimated. in general, lupinseed paste allowed faster growth of A. oryzae than soybean paste at the initial growth phase. The lag time to form the colony was 24.0 hrs on lupinseed paste and 44.4 hrs on soybean paste. The growth rate after colony formation was, however, 7.05 mm/day for lupinseed paste and 8.83mm/day for soybean paste, which indicated that the growth rate after the lag period was faster on soybean compared to lupinseed. The sporulation time of the mold was related to the lag time for the colony formation. The measurement of hyphae length on whole beans could be used as a simple and rapid method of estimating the growth property of mold on different substrates.11 showed that the growth of A. oryzae was partly hindered by the thick hull of the lupinseed.

• Fisheries and Aquatic Sciences
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• v.13 no.1
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• pp.12-17
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• 2010

This study was conducted to evaluate the potential of a microbial fermentation procedure to improve the functional qualities of seaweeds. Aspergillus oryzae, which has been used in traditional Korean fermented foods, was inoculated and cultivated in an aqueous extract of sea tangle (Laminaria japonica). Fermentation of the sea tangle extract by A. oryzae for 4 days resulted in a 3-fold increase in $\gamma$-aminobutyric acid (GABA) content. GABA is known to be a bioactive compound. Fungal fermentation of the extract also enhanced its antioxidant activity and increased its total content of phenolic compounds. It was assumed that these changes stemmed from the biodegradation of active compounds of the sea tangle packaged within its rigid structural matrix or occurred as result of fungal fermentation. These results suggested that the application of microbial fermentation to the processing of seaweeds will help in the development of processed foods to meet consumer demands.