• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.36-39
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• 2013

We introduce a high-performance microbial fuel cell (MFC) that was operated using a 0.1M bicarbonate buffer as the cathodic electrolyte. The MFC had a 136.42 $mW/m^2$ maximum power density under continuous feeding of 5 mM acetate as fuel. Results of the electrode potential measurements showed that the cathode potential of the bicarbonate-buffered condition was higher than the phosphate-buffered condition, although the phosphate condition had less interfacial resistance between the membrane and electrolyte. Therefore, we posit here that the increased power of the bicarbonate-buffered MFC may be caused by the higher cathode potential rather than by the interfacial membrane-electrolyte resistance.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.734-738
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• 2008

The physicochemical and in vitro physiological properties of soluble dietary fiber (SDF) from wax gourd (Benincasa hispida) pulp and peel were investigated. The pulp was composed of 11.4% SDF and 24.3% insoluble dietary fiber (IDF), while the peel contained 3.2% SDF and 43.3% IDE The predominant sugar in the SDF of the wax gourd pulp and peel was uronic acid, followed by galactose and rhamnose. The SDFs from the wax gourd pulp and peel gave similar elution patterns, with 4 main neutral sugar and uronic acid peaks eluted by 0.4, 0.5, 1, and 2 M ammonium acetate buffer. The pulp SDF had a much higher glucose retardation index (GRI) than the peel SDF for all measurement times. The pulp SDF showed strong growth-inhibiting activity against Escherichia coli and Clostridium perfringens, whereas the peel SDF produced strong growth-promoting activity against Bifidobacterium longum, Bifidobacterium infantis, and Lactobacillus brevis when compared to glucose.

• Bulletin of the Korean Chemical Society
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• v.4 no.3
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• pp.139-143
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• 1983

${\beta}$-N-Acetyl-D-glucosaminidase B was highly purified with the following sequence of steps; DEAE-cellulose, CM-cellulose, and Sephadex G-200 gel filtration chromatograpies. The specific activity of the purified ${\beta}$ -N-acetyl-D-glucosaminidase B was 2.2 units/mg protein with 12.9 % yield and 196.2 fold purity. The purified ${\beta}$-N-acetyl-D-glucosaminidase B showed single band on polyacrylamide gel electrophoresis. The final preparation of ${\beta}$ -N-acetyl-D-glucosaminidase B was completely free friom arylsulfatase and ${\beta}$-glucuronidase. ${\beta}$ -N-Acetyl-D-glucosaminidase B had pH optimum of 4.5 in 0.5 M sodium citrate buffer. The molecular weight of ${\beta}$-N-acetyl-D-glucosaminidase B was 133,000 by Sephadex G-200 gel filtration. The Km value of ${\beta}$-N-acetyl-D-glucosaminidase B using p-nitrophenyl-N-acetyl-${\beta}$-D-glucosaminide as substrate was 1.0 mM and $V_{max}$ was 0.014 ${\mu}$ mole/min. ${\beta}$-N-Acetyl-D-glucosaminidase B was stable at $55^{circ}C$ for 70 minutes. The crude ${\beta}$ -N-acetyl-D-glucosamiinidase in 70 % ammonium sulfate retained 93 % activity after 7 months storage at -$55^{circ}C$. Bovine serum albumin, sodium chloride, and phosphate activated ${\beta}$ -N-Acetyl-D-glucosaminidase B. N-Acetyl-D-glucosamine, ${\alpha}$-methyl-D-mannoside, and acetate inhibited ${\beta}$ -N-acetyl-D-glucosaminidase B.

• Journal of Microbiology and Biotechnology
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• v.1 no.3
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• pp.157-162
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• 1991

Conditions for glutathione production in E. coli cells which possess pGH501 (2 gshI+gshII) were studied. In terms of ATP supply for the glutathione synthesis, two different systems have been constructed and compared. When the acetate kinase reaction of E. coli was used for ATP generation, 20 mM of L-cysteine was completely converted to glutathione by toluene-treated E. coli cells (100 mg/ml) harboring pGH501 within 2 h at $37^{\circ}C$. However, considering the economical aspects, the glycolytic pathway of yeast was chosen as a better system for ATP generation. The optimal concentrations of reactants for glutathione production were determined to be as follows; 80 mM L-glutamate, 20 mM L-cysteine, 20 mM glycine, 20 mM $MgCl_2$, 50 mM potassium phosphate buffer (pH 7.5), 400 mM glucose, polyoxyethylene stearylamine ($5\;\mul/ml$), toluene-treated E. coli HB101/pGH501 (100 mg/ml), and dried yeast cells (400 mg/ml). The conversion ratio of L-cysteine to glutathione was 80% (about 5 mg/ml) under optimal condition within 6 h at $37^{\circ}C$.

• Journal of Practical Agriculture & Fisheries Research
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• v.16 no.1
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• pp.25-35
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• 2014

Tremella fuciformis produces white jelly fruitbody which is used as a special food in the orient. Symbiotic relationship between T. fuciformis and Hypoxylon sp. is important for mass production of fruitbody in T. fuciformis. T. fuciformis showed the peak of 24mg/2mL on the 9th day, after that mycelial growth maintained a gentle curve. Protein content increased into 0.69㎍/mL in rapid, T. fuciformis fruiting body maintained high galactose, mycelia of T. fuciformis showed 42.6% trehalose.

• The Korean Journal of Zoology
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• v.26 no.4
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• pp.271-282
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• 1983

The authors observed the ultrastructure of the pigment cells of the frog, Rana nigromaculata Hallowell, during the hibernation. The specimens from the skin were fixed in 2.5% glutaraldehyde-paraform-aldehyde fixative in phosphate buffer at pH 7.2 prior to fixation in 2% osimium tetroxide, dehydrated in graded ethanol and acetone, embedded in Epon 812 mixture, and sectioned with LKB-ultramicrotome. the ultrathin sections were contrasted with uranyl acetate and lead citrate and observed with a JEOL-100B electron microscope. The results were as follows. In hibernating phase, pigment cells of the frog were consisted of the three kinds of chromatophores (xanthophore, iridophore and melanophore) in their dorsal skin. The traits of these cells were as follows. 1. Xanthophores A. Xanthophores were filled with pterinosomes and carotenoid vesicles. Many ribosomes, a few mitochondria and glycogen particles were dispersed in the cytoplasm. B. Pterinosomes were spherical or ellipsoidal in shape. They were divided into 6 types (type I, type II, type III, type IV, type V, type VI pterinosomes) by the their inner structure and especially, type I, type II, type III pterinosomes were well developed.

• Development and Reproduction
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• v.5 no.2
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• pp.123-129
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• 2001

When mammalian oocytes undergo maturation, cumulus cells surrounding the oocyte exhibit remodeling of their structure known as cumulus expansion. Many molecules including hyaluronic acid participate in this remodeling. The present study aimed to investigate a possible existence of matrix metalloproteinases(MMPs) in the extracellular matrix(ECM) of human oocyte-cumulus complex. ECM was extracted from the human oocyte-cumulus complex. Gelatin gel zymogram of ECM exhibited 7 gelatinases having molecular weight of 300kDa, 240kDa, 200kDa, 180kDa, 116kDa, 97kDa, and 84kDa. This gelatinase profile was very different from that of ovarian mural granulosa cell extract or white blood cell extract, indicating that the oocyte-cumulus complex donating ECM was free from other than cumulus cells. When ethylenediaminetetraacetic acid or 1', 10'-phenanthroline was added to the reaction buffer during zymographic development, almost gelatinase activities were abolished, suggesting that they were MMPs. Following incubation of ECM in the presence of aminophenylmercuric acetate, an activator of proMMPs, 4 gelatinases of 240kDa, 180kDa, 97kDa, and 84kDa disappeared with the concomitant appearance of 80kDa, 65kDa, and 60kDa gelatinases. Based upon these observation, it is suggested that ECM of the human oocyte-cumulus complex consists of gelatinases, presumed to be MMP-2 and MMP-9 isoforms.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.6
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• pp.856-863
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• 2013

An in vitro gas production technique was used in this study to elucidate the effect of two strains of active live yeast on methane ($CH_4$) production in the large intestinal content of pigs to provide an insight to whether active live yeast could suppress $CH_4$ production in the hindgut of pigs. Treatments used in this study include blank (no substrate and no live yeast cells), control (no live yeast cells) and yeast (YST) supplementation groups (supplemented with live yeast cells, YST1 or YST2). The yeast cultures contained $1.8{\times}10^{10}$ cells per g, which were added at the rates of 0.2 mg and 0.4 mg per ml of the fermented inoculum. Large intestinal contents were collected from 2 Duroc${\times}$Landrace${\times}$Yorkshire pigs, mixed with a phosphate buffer (1:2), and incubated anaerobically at $39^{\circ}C$ for 24 h using 500 mg substrate (dry matter (DM) basis). Total gas and $CH_4$ production decreased (p<0.05) with supplementation of yeast. The methane production reduction potential (MRP) was calculated by assuming net methane concentration for the control as 100%. The MRP of yeast 2 was more than 25%. Compared with the control group, in vitro DM digestibility (IVDMD) and total volatile fatty acids (VFA) concentration increased (p<0.05) in 0.4 mg/ml YST1 and 0.2 mg/ml YST2 supplementation groups. Proportion of propionate, butyrate and valerate increased (p<0.05), but that of acetate decreased (p<0.05), which led to a decreased (p<0.05) acetate: propionate (A: P) ratio in the both YST2 treatments and the 0.4 mg/ml YST 1 supplementation groups. Hydrogen recovery decreased (p<0.05) with yeast supplementation. Quantity of methanogenic archaea per milliliter of inoculum decreased (p<0.05) with yeast supplementation after 24 h of incubation. Our results suggest that live yeast cells suppressed in vitro $CH_4$ production when inoculated into the large intestinal contents of pigs and shifted the fermentation pattern to favor propionate production together with an increased population of acetogenic bacteria, both of which serve as a competitive pathway for the available H2 resulting in the reduction of methanogenic archaea.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.187-191
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• 2004

For the production of $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid (ascorbic acid-2-g1ucoside, AA-2G) from ascorbic acid, the usability of spinach seed as the source of ${\alpha}-glucosidase$ having transglucosylation activity was studied. The optimum conditions for the production of AA-2G from ascorbic acid and glucose donor were investigated by using crude extract of Spinachia oleracea L. Woosung, the selected source of enzyme. The production of AA-2G was the highest with 1.053 mM when spinach seeds were grown for 2 days after germination. Maltose was the most effective glucose donor, and the optimum concentration of ascorbic acid and maltose were 175 mM and 225 mM, respectively. The optimum concentration of ${\alpha}-glucosidase$ was 60 units. The most effective buffer was sodium acetate and its optimum concentration was 175 mM. The optimum pH and temperature were 5.0 and $65^{\circ}C$, respectively. Under the optimum condition, 2.14 mM of AA-2G was produced from ascorbic acid after 50 minutes of reaction.

• Journal of Microbiology and Biotechnology
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• v.32 no.2
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• pp.187-194
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• 2022

Two α-ʟ-arabinofuranosidases (BfdABF1 and BfdABF3) and a β-ᴅ-xylosidase (BfdXYL2) genes were cloned from Bifidobacterium dentium ATCC 27679, and functionally expressed in E. coli BL21(DE3). BfdABF1 showed the highest activity in 50 mM sodium acetate buffer at pH 5.0 and 25℃. This exo-enzyme could hydrolyze p-nitrophenyl arabinofuranoside, arabino-oligosaccharides (AOS), arabinoxylo-oligosaccharides (AXOS) such as 3²-α-ʟ-arabinofuranosyl-xylobiose (A³X), and 2³-α-ʟ-arabinofuranosyl-xylotriose (A²XX), whereas hardly hydrolyzed polymeric substrates such as debranched arabinan and arabinoxylans. BfdABF1 is a typical exo-ABF with the higher specific activity on the oligomeric substrates than the polymers. It prefers to α-(1,2)-ʟ-arabinofuranosidic linkages compared to α-(1,3)-linkages. Especially, BfdABF1 could slowly hydrolyze 2³,3³-di-α-ʟ-arabinofuranosyl-xylotriose (A²⁺³XX). Meanwhile, BfdABF3 showed the highest activity in sodium acetate at pH 6.0 and 50℃, and it has the exclusively high activities on AXOS such as A³X and A²XX. BfdABF3 mainly catalyzes the removal of ʟ-arabinose side chains from various AXOS. BfdXYL2 exhibited the highest activity in sodium citrate at pH 5.0 and 55℃, and it specifically hydrolyzed p-nitrophenyl xylopyranoside and xylo-oligosaccharides (XOS). Also, BfdXYL2 could slowly hydrolyze AOS and AXOS such as A³X. Based on the detailed hydrolytic modes of action of three exo-hydrolases (BfdABF1, BfdABF3, and BfdXYL2) from Bf. dentium, their probable roles in the hemiceullose-utilization system of Bf. dentium are proposed in the present study. These intracellular exo-hydrolases can synergistically produce ʟ-arabinose and ᴅ-xylose from various AOS, XOS, and AXOS.