• Journal of Microbiology
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• 제43권6호
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• pp.487-492
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• 2005

This study demonstrated that the brown rot basidiomycete Fomitopsis palustris was able to degrade crystalline cellulose (Avicel). This fungus could also produce the three major cellulases (exoglucanases, endoglucanases, and $\beta-glucosidase$) when the cells were grown on $2.0\%$ Avicel. Avicel degraded by F. palustris showed a decrease in relative crystallinity from $83\%\;to\;78.5\%$ after 14 days of incubation. The characterization study indicated that optimum pH was 4.5 and optimum temperature was $70^{\circ}C$ for exoglucanase (cellobiohydrolase) activity. Hydrolysis of Avicel by the crude enzyme from F. palustris yielded 1.6 mg/ml of glucose after 43 h, which corresponded to a cellulose conversion degree of $3.2\%$. Therefore, this study revealed for the first time that the brown rot basidiomycete F. palustris produces cellulases capable of yielding soluble sugars from crystalline cellulose.

• Environmental Engineering Research
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• 제22권2호
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• pp.224-229
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• 2017

Zinc oxide nanoparticles (ZnO NPs) have been used as additives in a variety of consumer products. While these particles may enter the environment, only a limited number of studies have investigated the effects of ZnO NPs on soil exoenzymes. Here, we investigate the long-term effects of ZnO NPs at concentrations of 50 and 500 mg/kg on the activities of six soil exoenzymes in planted soils: Dehydrogenase, fluorescein diacetate (FDA) hydrolase, urease, acid phosphatase, arylsulfatase, and ${\beta}-glucosidase$. Significant effects were observed at one or more time points for all enzymes except for FDA hydrolase. These effects included both decreases and increases in enzyme activity. Our results suggest that ZnO NP treatments of 50 and 500 mg/kg can adversely affect soil enzymes, particularly acid phosphatase and urease, and thus, these data may have implications for phosphorous and nitrogen cycles in the soil.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1003-1008
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• 2009

The $O_sO_4$-catalyzed dihydroxylations of a monosubstituted allylic amine and $\gamma-amino-\alpha,\;\beta-unsaturated$ (E)-esters with bulky alkyl groups showed a high anti-selectivity. Since the acyclic conformation of N-acyloxy protected allylic amines was efficiently controlled by a bulky t-Bu or OBO ester group, the anti diastereoselectivity of >12.5:1 was obtained without applying a chiral reagent. The synthetic utility of the present method was demonstrated by a stereoselective and efficient synthesis of an $\alpha$-glucosidase inhibitor 15 from commercially available N-Cbz-L-serine 6 in 11 steps and 31% yield.

• 미생물학회지
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• 제18권3호
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• pp.133-147
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• 1980

Washed mycelia of Aspergillus nidulans FGSC159 were incubated in CMC minimal liquid medium and the culture filtrate which contained induced extracellular cellulase was fractionated by a three-step procedure including chromatography on Bio-Gel P-150, chromatography on DEAE-Sephadex A-50 and chromatography on Sephadex G-100. Three CMCase components ; F-I-Ia, F-I-Ib and F-II-Ia were prepared. No enzyme activity toward avicel could be detected in these components. Similarly, there was no ${\beta}-glucosidase$ activity. pH-optima of the three components were all 5.0 in acetate buffer. Temperature-optima for the activities of F-I-Ia, F-Ib and F-II-Ia were $45^{\circ}C,\;40^{\circ}C\;and\;50^{\circ}C$, respectively. F-II-Ia was shown to be more thermostable than the other two components. F-II-Ia was proved to have quite a different substrate specificity and action property and action property from those of F-I-Ia and F-I-Ib by product analysis on liquid chromatography.

• Journal of Microbiology
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• 제43권5호
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• pp.456-462
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• 2005

More than seventy strains of aerobic bacteria showing ${\beta}$-glucosidase activity were isolated from a ginseng field, using a newly designed Esculin-R2A agar, and identified by their 16S rRNA gene sequences. Of these microorganisms, twelve strains could convert the major ginsenoside, $Rb_1$, to the pharmaceutically active minor ginsenoside Rd. Three strains, Burkholderia pyrrocinia GP16, Bacillus megaterium GP27 and Sphingomonas echinoides GP50, were phylogenetically studied, and observed to be most potent at converting ginsenoside $Rb_1$ almost completely within 48 h, as shown by TLC and HPLC analyses.

• Mycobiology
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• 제37권4호
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• pp.267-271
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• 2009

A fungal strain producing a high level of cellulase was selected from 320 fungal isolates and identified as Aspergillus sp. This strain was further improved for cellulase production by sequential treatments by two repeated rounds of $\gamma$-irradiation of $Co^{60}$, ultraviolet treatment and four repeated rounds of treatment with N-methyl-N'-nitro-N-nitrosoguanidine. The best mutant strain, Aspergillus sp. XTG-4, was selected after screening and the activities of carboxymethyl cellulase, filter paper cellulase and $\beta$-glucosidase of the cellulase were improved by 2.03-, 3.20-, and 1.80-fold, respectively, when compared to the wild type strain. After being subcultured 19 times, the enzyme production of the mutant Aspergillus sp. XTG-4s was stable.

• Mycobiology
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• 제35권3호
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• pp.162-165
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• 2007

Thirty seven species of Fusarium were evaluated for their ability of producing extracellular enzymes using chromogenic medium containing substrates such as starch, cellobiose, CM-cellulose, xylan, and pectin. Among the tested species Fusarium mesoamericanum, F. graminearum, F. asiaticum, and F. acuminatum showed high ${\beta}$-glucosidase acitivity. Xylanase activity was strongly detected in F. proliferatum and F. oxysporum. Strong pectinase activity was also found in F. oxysporum and F. proliferatum. Amylase activity was apparent in F. oxysporum. No clear activity in cellulase was found from all the Fusarium species tested.

• 한국식품영양학회지
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• 제10권1호
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• pp.92-96
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• 1997

시판 식혜에는 설탕과 프룩토오스, 글루코오스, 말토오스 및 여러 사이즈의 말토올리고당, 한계덱스트린이 함유되어 있다. 그 중 한계덱스트린은 0.09%, 밥알은 0.2%를 나타냈다. 1H-NMR 분석 결과, 한계덱스트린은 $\alpha$-1,4-결합 및 $\alpha$-1,6-결합이 15:1의 비율을 나타냈다. Pullulanase 처리로, 말토오스에서 글루코오스 10잔기 이상의 말토올리고당까지 다양한 분포를 나타냈다. 한계덱스트린은 여러 아미라아제 처리 결과, 전통식혜보다 가수분해율이 훨씬 높았다. $\alpha$-글루코시다아제와 타액 $\alpha$-아밀라아제를 공동 작용시킨 경우는 62% 가수분해되었다. 그러나, 밥알의 가수분해율이 매우 낮았다. 그래서 전통 식혜에 비해 한계덱스트린의 비피두스 인자로서의 효과는 적고, 밥알의 식이섬유 작용은 커졌다.

• 대한한의학방제학회지
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• 제27권3호
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• pp.223-236
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• 2019

Dengropanax morfiferus (D), Broussonitia kazinoki (B), and Cudriania tricuspidata (E), a widely cultivated species in South Korea, has been used as traditional medicine to treat numerous diseases. In this study, we evaluated the antidiabetic effects in a various signaling mechanisms using mixed extract and major component contents were analyzed by HPLC in the combined extracts from Dengropanax morfiferus, Broussonitia kazinoki, and Cudriania tricuspidata (DBCE). DBCE inhibited ${\alpha}$-glucosidase and ${\alpha}$-amylase activation and showed potent antioxidant effects, which are evaluated using DPPH, ABTS, and SOD assay. Cytokines, which are released by inflammatory cells in pancreatic islets, are involved in the pathogenesis of type 1 diabetes mellitus. DBCE showed the protective effects in RINm5F cells against cytokines-induced damage by suppressing inducible nitric oxide (NO) synthase and COX-2 expression and NO production. Insulin resistance is the primary characteristic of type 2 diabetes. Therefore, the regulatory effect of DBCE on glucose uptake and production are investigated in insulin-responsive human HepG2 cells. DBCE stimulated glucose uptake, prevented Glut2 and phosphor-IRS1 downregulation induced by high glucose (HG, 30 mM). Moreover, DBCE pretreatment diminished glucose levels, PEPCK and G6Pase overexpression provoked by HG. These findings suggest that DBCE might be used for diabetes treatment through alpha-glucosidase or alpha-amylase activity regulation, pancreatic beta cell protection, hepatic glucose sensitivity improvement. Cytokines, which are released by inflammatory cells' infiltrations around the pancreatic islets, are involved in the pathogenesis of type 1 diabetes mellitus.

• 디지털융복합연구
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• 제17권7호
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• pp.275-284
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• 2019

난초과의 석곡(石斛; Dendrobii herba) 에탄올 추출물(EED)의 항당뇨 활성 및 항당뇨 기전을 조사하였다. 스트렙토 조 토신에 의해 유도된 당뇨병 마우스에서 EED를 하루 4회 경구 투여하여 공복 혈당, 당화혈색소 수치, 인슐린 수치 및 글루탐산 옥살 아세트산 트랜스 아미나 아제 및 글루탐산 피루브산 트랜스 아미나 아제의 간 기능을 감소시키는 실험연구를 통해 그 약리적 기전을 밝혀내고자 했다. EED는 L6 근육 세포에서 세포 내 포도당 섭취뿐만 아니라 RINm5F 베타 세포에서 포도당에 의한 인슐린 분비를 증가시켰다. 따라서 EED는 인슐린 분비를 증가시킬 뿐만 아니라 세포 당 흡수를 증가시킴으로써 항당뇨병 활성을 나타내는데 커다란 가능성을 보여주었으며, 향후 석곡(石斛; Dendrobii herba) 에탄올 추출물에 대한 약리적 기전에 대한 연구가 더욱 활발하게 이루어져 당뇨병 치료에 큰 공헌을 할 수 있게 되기를 기대해본다.