• Journal of Microbiology and Biotechnology
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• 제21권3호
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• pp.236-242
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• 2011

A psychrotrophic bacterium, Arthrobacter sp. ON14, isolated from Antarctica, was shown to exhibit a high ${\beta}$-galactosidase activity at a low temperature. A genomic library of ON14 was constructed and screened for ${\beta}$-galactosidase genes on functional plates containing 5-bromo-4-chloro-3-indolyl-${\beta}$-D-galactopyranoside (X-gal) as the substrate. Two different ${\beta}$-galactosidase genes, named as galA, galB, were found in ON14. Computational analyses of the genes revealed that the encoded protein GalA belongs to family 2 of glycosyl hydrolysases and is a cold-active protein, whereas GalB belongs to family 42 of glycosyl hydrolysases and is a mesophilic protein. Reverse transcription analyses revealed that the expression of galA is highly induced at a low temperature ($4^{\circ}C$ ) and repressed at a high temperature ($28^{\circ}C$ ) when lactose is used as the sole carbon source. Conversely, the expression of galB is inhibited at a low temperature and induced at a high temperature. The purified GalA showed its peak activity at $15^{\circ}C$ and pH 8. The mineral ions $Na^+$, $K^+$, $Mg^{2+}$, and $Mn^{2+}$ were identified as enzyme activators, whereas $Ca^{2+}$ had no influence on the enzyme activity. An enzyme stability assay revealed that the activity of GalA is significantly decreased when it is incubated at $45^{\circ}C$ for 2 h, and all its activity is lost when it is incubated at $50^{\circ}C$.

• Food Science and Biotechnology
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• 제17권5호
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• pp.1115-1118
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• 2008

${\alpha}$-Galactosidase gene (aga) from Leuconostoc mesenteroides SY1 was expressed in a heterologous host, Lactobacillus brevis 2.14 using an Escherichia coli-Leuconostoc shuttle vector, pSJE. pSJEaga (pSJE carrying aga) was introduced into Lactobacillus brevis 2.14 by electroporation and transformation efficiency was $1.1{\times}10^3$ per ${\mu}g$ DNA. L. brevis transformants (TFs) showed higher ${\alpha}$-galactosidase (${\alpha}$-Gal) activities than cells containing pSJE. Transcription levels of aga in L. brevis 2.14 grown on different carbon sources (1%, w/v) were examined by slot blot analysis. Aga transcript levels and ${\alpha}$-Gal activities were higher in cells grown on melibiose, raffinose, and galactose than cells on glucose, sucrose, and fructose. Western blot result showed that L. brevis 2.14 harboring pSJEaga produced much more ${\alpha}$-Gal when grown on melibiose than on glucose.

• Journal of Microbiology and Biotechnology
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• 제26권7호
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• pp.1267-1277
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• 2016

Currently, enzymatic synthesis of lactulose, a synthetic prebiotic disaccharide, is commonly performed with glycosyl hydrolases. In this work, a new type of lactulose-producing biocatalyst was developed by displaying β-galactosidase from Bacillus stearothermophilus IAM11001 (Bs-β-Gal) on the surface of Bacillus subtilis 168 spores. Localization of β-Gal on the spore surface as a fusion to CotX was verified by western blot analysis, immunofluorescence microscopy, and flow cytometry. The optimum pH and temperature for the resulting spore-displayed β-Gal was 6.0 and 75℃, respectively. Under optimal conditions, it showed maximum activity of 0.42 U/mg spores (dry weight). Moreover, the spore-displayed CotX-β-Gal was employed as a whole cell biocatalyst to produce lactulose, yielding 8.8 g/l from 200 g/l lactose and 100 g/l fructose. Reusability tests showed that the spore-displayed CotX-β-Gal retained around 30.3% of its initial activity after eight successive conversion cycles. These results suggest that the CotX-mediated spore-displayed β-Gal may provide a promising strategy for lactulose production.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권5호
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• pp.337-340
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• 2001

A galactooligosaccharide(GalOS)-producing yeast, OE-20 was selected from forty seven strains of yeast growing in Korean traditional Meju (cooked soybean) and the yeast was tentatively identified as Kluyveromyces maxianus var lactis by its morphology and fermentation profile. A maximum yield of 25.1%(w/w) GalOS, which corresponds to 25.1 g of GalOS per liter, was obtained from the reaction of 100 g per liter of lactose solution at 3$0^{\circ}C$, pH 7.0 for 18 h with an intracellular crude $\beta$-galactosidase. Glucose and galactosidase were found to inhibit GalOS formation. The GalOS that were purified by active carbon and celite 545 column chromatography were supplemented in MRS media and a stimulated growth was observed of some intestinal bacteria. In particular the growth rate of Bifidobacterium infantis in the GalOS containing MRS broth increased up to 12.5% compared to that of the MRS-glucose broth during a 48h incubation period.

• Journal of Microbiology and Biotechnology
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• 제32권6호
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• pp.749-760
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• 2022

α-Galactosidase is a debranching enzyme widely used in the food, feed, paper, and pharmaceuticals industries and plays an important role in hemicellulose degradation. Here, T26, an aerobic bacterial strain with thermostable α-galactosidase activity, was isolated from laboratory-preserved lignocellulolytic microbial consortium TMC7, and identified as Parageobacillus thermoglucosidasius. The α-galactosidase, called T26GAL and derived from the T26 culture supernatant, exhibited a maximum enzyme activity of 0.4976 IU/ml when cultured at 60℃ and 180 rpm for 2 days. Bioinformatics analysis revealed that the α-galactosidase T26GAL belongs to the GH36 family. Subsequently, the pET-26 vector was used for the heterologous expression of the T26 α-galactosidase gene in Escherichia coli BL21 (DE3). The optimum pH for α-galactosidase T26GAL was determined to be 8.0, while the optimum temperature was 60℃. In addition, T26GAL demonstrated a remarkable thermostability with more than 93% enzyme activity, even at a high temperature of 90℃. Furthermore, Ca²⁺ and Mg²⁺ promoted the activity of T26GAL while Zn²⁺ and Cu²⁺ inhibited it. The substrate specificity studies revealed that T26GAL efficiently degraded raffinose, stachyose, and guar gum, but not locust bean gum. This study thus facilitated the discovery of an effective heat-resistant α-galactosidase with potent industrial application. Meanwhile, as part of our research on lignocellulose degradation by a microbial consortium, the present work provides an important basis for encouraging further investigation into this enzyme complex.

• Reproductive and Developmental Biology
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• 제33권3호
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• pp.157-162
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• 2009

This study was performed to comprehend the developmental characteristics of cloned embryos knocked out (KO) of $\alpha$-1,3-galactosyltransferase (GalT) gene. Immature oocytes were collected and cultured for 40 hrs (1-step) or 20hrs (with hormone) + 20hrs (without hormone) (2-step). The embryos transferred with miniature pig ear fibroblast cell were used as control. The reconstructed embryos were cultured in PZM-3 with 5% $CO_2$ in air at $38.5^{\circ}C$ for 6 days. To determine the quality of the blstocysts, TUNEL and quantitative realtime RT-PCR were performed. The embryos were transferred to a surrogate (Landrace) at an earlier stage of the estrus cycle. The maturation rate was significantly higher in 2-step method than that of 1-step (p<0.05). The blastocyst development of GalT KO embryos was significantly lower than that of normal cloned embryos (p<0.05). The total and apoptotic cell number of GalT KO blastocysts was not different statistically from control. The relative abundance of Bax-$\alpha$/Bcl-xl ratio was significantly higher in both cloned blastocysts than that of in vivo blastocysts (p<0.05). Taken together, it can be postulated that the lower developmental potential and higher expression of apoptosis related genes in GalT KO SCNT embryos might be a cause of a low efficiency of GalT KO cloned miniature pig production.

• 한국식품영양과학회지
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• 제41권6호
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• pp.790-795
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• 2012

본 연구는 울금의 산업적 실용화를 극대화시키기 위해 Aspergillus oryzae를 이용하여 산업용 규격에서 생산된 발효울금의 일반성분 및 미량성분 분석과 발효울금을 이용하여 동물모델에서 14일간 예비 투여하고 GalN으로 급성 간독성을 유발한 후 혈액 중 간기능 지표물질의 변화 및 간조직의 조직학적 관찰을 통해 GalN로 유발된 급성 간독성에 발효울금의 간기능 보호효과를 평가하고자 하였다. 발효울금의 일반성분은 수분 0.15%, 조지방 4.68%, 조단백 4.35%, 조섬유 6.92%, 조회분은 6.83%로 분석되었다. 발효울금의 미량성분은 P, Mg, Ca 순으로 분석되었다. 간기능 지표효소인 AST와 ALT의 활성은 발효울금 300 mg/kg/day과 silymarin 150 mg/kg/day를 투여한 군에서 GalN만을 투여한 군과 비교하여 통계적으로 유의한 결과를 나타내어 발효울금 300 mg/kg/day의 예비 투여는 GalN에 대한 급성 간독성에 대해 보호효과를 갖으며, 양성 대조군인 silymarin 150 mg/kg/day 투여와 비교하여 유사한 간독성 보호 활성을 갖는 것으로 나타났다. ALP의 경우 발효울금을 100 mg/kg/day로 투여한 군에서만 GalN만을 투여한 군과 통계적으로 유의한 감소를 나타났고 300 mg/kg/day 발효울금을 투여한 군과 silymarin 투여군은 통계적 유의차가 나타나지 않았다. 중성지방의 경우 발효울금 300 mg/kg/day 투여군만 GalN만을 투여한 군과 비교하여 통계적 유의차가 나타났으나 silymarin 투여군에서는 동일한 효과가 나타나지 않았다. GalN으로 유도된 급성 간독성의 조직병리학적 결과 GalN만을 투여한 군에서 세포괴사 및 침윤된 염증세포, 카운실만소체의 괴사가 심하게 나타났으며 300 mg/kg/day 발효울금 투여군과 150 mg/kg/day silymarin 투여군에서 간조직의 괴사 및 염증의 개선효과를 관찰할 수 있었다. 혈청 분석 및 조직병리학적 결과를 종합한 결과 GalN 유발 간독성에 대한 개선효과는 300 mg/kg/day 발효울금 투여군과 150 mg/kg/day silymarin 투여군에서 나타나는 것으로 판단할 수 있었다. 이러한 결과로부터 본 연구에서 사용한 Aspergillus oryzae로 발효하여 산업적 규격에서 생산된 발효울금은 간기능 저하 개선 기능을 갖는 새로운 기능성 소재로서 간질환과 관련된 다양한 기능성식품 개발에 이용될 수 있을 것으로 생각된다.

• BMB Reports
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• 제39권3호
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• pp.304-310
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• 2006

Transcription factor NF-E2-related factor 2 (Nrf2) regulates the induction of Phase II detoxifying enzymes and antioxidant enzymes in response to many cancer chemopreventive compounds. In this study, we investigated the role of receptor associated coactivator (RAC3) or steroid receptor coactivator-3 (SRC3) and other nuclear co-regulators including CBP/p300 (CREB-binding protein), CARM1 (Coactivator-associated arginine methyltransferase), PRMT1 (Protein arginine methyl-transferase 1), and p/CAF (p300/CBP-associated factor) in the transcriptional activation of a chimeric Gal4-Nrf2-Luciferase system containing the transactivation domain (TAD) of Nrf2 in HepG2 cells. The results indicated that RAC3 up-regulated the transactivation activity of Gal4-Nrf2-(1-370) in a dose-dependent manner. The enhancement of transactivation domain activity of Gal4-Nrf2-(1-370) by RAC3 was dampened in the presence of dominant negative mutants of RAC3. Next we studied the effects of other nuclear co-regulators including CBP/p300, CARM1, PRMT1 and p/CAF, and the results showed that they had different level of positive effects on this transactivation domain activity of Gal4-Nrf2-(1-370). But importantly, synergistic effects of these co-regulators in the presence of RAC3/SRC3 on the transactivation activity of Gal4-Nrf2-(1-370) were observed. In summary, our present study showed for the first time that the 160 RAC3/SRC3 is involved in the functional transactivation of TAD of Nrf2 and that the other nuclear co-regulators such as CBP/p300, CARM1, PRMT1 and p/CAF can also transcriptionally activate this TAD of Nrf2 and that they could further enhance the transactivation activity mediated by RAC3/SRC3.

• 동의생리병리학회지
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• 제27권5호
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• pp.617-624
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• 2013

The purpose of this study is to investigate the protective effects of 25 herbal formulas on acetaminophen (APAP) or D-galactosamine (D-GalN)-induced hepatotoxicity in primary rat hepatocytes. Cell viability was measured using by Cell Counting Kit-8. 15 kinds of herbal formulas significantly reversed the cell viabilities of D-GalN-treated rat hepatocytes compared with D-GalN alone (p<0.05). In particular, 9 herbal formulas (Bangpungtongseong-san, Bojungikgi-tang, Galgeun-tang, Gumiganghwal-tang, Guibi-tang, Sagunja-tang, Samsoeum, Pyeongwi-san and Yijin-tang) showed the potent protective effects. However, 8 herbal formula exerted weak protective effects and 2 herbal formula did not exert effects on hepatotoxicity by D-GalN. On APAP-induced hepatotoxicity, 7 kinds of herbal formulas increased the viabilities of hepatocytes compare with APAP alone (p<0.05). These results could be provide a valuable information for the future in vivo or clinical studies to predict the hepatoprotective effects of herbal formulas.

• 한국식품영양과학회지
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• 제37권2호
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• pp.177-183
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• 2008

본 연구에서는 실험동물에 민들레 열수추출물 식이를 급여한 후, GalN으로 간손상을 유발함으로써 그 예방효과를 혈액중의 생화학적 변화 및 간조직의 효소적인 변동을 통해서 규명하고자 하였다. GalN의 투여로 현저히 증가하였던 AST, ALT의 활성은 민들레 열수추출물 투여로 억제되었으나 군간의 차이는 보이지 않았고 ALP의 활성과 TBARS 함량은 3%의 추출물을 급여한 군에서 유의적인 감소를 보였다. GalN의 투여로 현격하게 높아졌던 혈중 $TNF-{\alpha}$의 농도 또한 감소하는 경향을 확인하였으나 유의적인 차이는 보이지 않았다. GalN의 투여로 억제되었던 catalase, GSH-reductase, Mn-SOD의 활성은 민들레 추출물 투여로 유의적인 회복이 관찰되었으나 GSH-px의 활성은 그 경향만을 확인할 수 있었다. 조직 검경을 통해 민들레 열수추출물의 간염 예방효과를 확인한 결과 GalN으로 인해 유발된 광범위한 간세포의 괴사와 변성, 지방변성 등이 민들레 열수추출물식이로 다소 감소하는 것을 관찰할 수 있었다. 이상의 결과로 민들레 열수추출물은 AST, ALT와 ALP의 활성 및 산화적 스트레스를 감소시키고 활성산소 해독계에 관여하는 효소의 활성을 증가시킴으로써 GalN으로 인한 간 손상을 예방하는 것으로 사료된다.