• Bulletin of the Korean Mathematical Society
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• v.44 no.2
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• pp.225-231
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• 2007

Given an injective envelope E of a left R-module M, there is an associative Galois group Gal$({\phi})$. Let R be a left noetherian ring and E be an injective envelope of M, then there is an injective envelope $E[x^{-1}]$ of an inverse polynomial module $M[x^{-1}]$ as a left R[x]-module and we can define an associative Galois group Gal$({\phi}[x^{-1}])$. In this paper we describe the relations between Gal$({\phi})$ and Gal$({\phi}[x^{-1}])$. Then we extend the Galois group of inverse polynomial module and can get Gal$({\phi}[x^{-s}])$, where S is a submonoid of $\mathbb{N}$ (the set of all natural numbers).

• Proceedings of the International Union of Geodesy And Geophysics Korea Journal of Geophysical Research Conference
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• 2003.05a
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• pp.19-19
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• 2003

본 연구에서는 국립해양조사원의 '해양2000호'를 통해 1996년과 1997년에 측정한 동해 지역의 중력자료에 대한 자료 처리를 하였다. 효과적인 자료처리를 위해 선상중력자료 처리에 필요한 각종 보정 절차와 문제점 등을 알아보았으며, 선상자료와 해면고도계자료의 비교 및 이를 통한 선상자료의 검증을 실시하였다. 선상중력자료는 측정과 처리 과정에 있어 여러 사항을 고려하여야 한다. 즉, 육상중력기점을 이용한 절대중력으로의 환산 문제, 선박 항해 위치의 부정확성에 기인하는 문제 및 중력계의 기계적 특성과 중력 측정이 이루어질 때의 해상 조건에 의한 영향 등으로 선상중력자료에 나타나는 여러 오차를 최소화하여야 한다. 선상중력자료로부터 각종 지구중력장 연구에 필요한 중력이상을 계산하기 위해 선상중력 측정시 기인되는 각종 요인의 오차를 고려한 효과적인 보정이 이루어져야 한다. 즉, 선상중력계의 기계변이 보정, 탐사선에 대한 위치 자료의 획득 및 필터링, 그리고 탐사선의 이동으로 인한 Eotvos 효과의 정확한 계산 및 보정이 필요하고, 선상중력계의 기계적 특성에 의해 나타나는 시간지연에 대한 보정도 필요하다. 또한 이러한 보정을 통해 계산한 중력 이상에서 각 교점의 오차를 보정하는 교정오차 보정도 실시하여야 한다. 특히, 탐사선의 이동으로 인한 지구자전 각속도의 상대적인 증감의 효과로 나타나는 Eotvos 효과의 영향은 선상중력자료의 정확도에 가장 큰 영향을 미친다. 이의 정확한 계산 및 보정을 위해서는 정확한 위치정보가 필요하며 본 연구에서는 이를 위해 GPS 항해정보에 대한 Kalman 필터를 실시하였고, Eotvos 효과에 대해 Savitzky-Golay 필터를 적용하여 최적의 Eotvos 보정을 시도하였다. 본 연구에서 계산된 동해지역의 중력이상에 대한 대력적인 범위는 경도 129° - 133°이고 위도 35° - 38.3° 부근이다. 이 지역에 대한 고도이상은 최소 -42.46 mGal에서 최고 161.13 mGal사이에 분포하며, 고도이상의 평균은 14.450 mGal이다. 또한 Bouguer 이상은 최소 -l5.09 mGal에서 최고 218.61 mGal이고 이의 평균은 82.681 mGal이다. 그리고 동해지역의 선상중력 측정지역에서 선상자료에 의한 중력이상과 Altimeter 자료에 의한 고도이상의 전반적인 윤곽은 비슷하면서도 일부 작은 이상의 차이가 나타났으며, 지형자료와 비교하여 보면 Altimeter에 의한 결과보다 선상측정에 의한 결과가 더욱 잘 일치하고 있어 본 연구에서 계산한 선상자료의 타당성을 알 수 있다. 고도이상의 차이는 최소 -25.94 mGal에서 최대 85.33 mGal의 차이를 보이며 차이의 평균은 3.517 mGal, RMS는 6.774 meal이다. 이는 비교적 큰 차이로 선상측정자료의 중요성과 필요성을 단적으로 나타내고 있다.

• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1653-1663
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• 2010

The first gene (${\alpha}$-gal1) encoding an extracellular ${\alpha}$-Dgalactosidase from the thermophilic fungus Talaromyces emersonii was cloned and characterized. The ${\alpha}$-gal1 gene consisted of an open reading frame of 1,792 base pairs interrupted by six introns that encoded a mature protein of 452 amino acids, including a 24 amino acid secretory signal sequence. The translated protein had highest identity with other fungal ${\alpha}$-galactosidases belonging to glycosyl hydrolase family 27. The ${\alpha}$-gal1 gene was overexpressed as a secretory protein with an N-terminal histidine tag in the methylotrophic yeast Pichia pastoris. Recombinant ${\alpha}$-Gal1 was secreted into the culture medium as a monomeric glycoprotein with a maximal yield of 10.75 mg/l and purified to homogeneity using Hisbinding nickel-agarose affinity chromatography. The purified enzyme was maximally active at $70^{\circ}C$, pH 4.5, and lost no activity over 10 days at $50^{\circ}C$. ${\alpha}$-Gal1 followed Michaelis-Menten kinetics ($V_{max}\;of\;240.3{\mu}M/min/mg,\;K_m\;of\;0.294 mM$) and was inhibited competitively by galactose ($K_m{^{obs}}$ of 0.57 mM, $K_i$ of 2.77 mM). The recombinant T. emersonii ${\alpha}$-galactosidase displayed broad substrate preference, being active on both oligo- and polymeric substrates, yet had strict specificity for the ${\alpha}$-galactosidic linkage. Owing to its substrate preference and noteworthy stability, ${\alpha}$-Gal1 is of particular interest for possible biotechnological applications involving the processing of plant materials.

• Journal of Life Science
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• v.11 no.1
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• pp.57-64
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• 2001

The cDNA encoding human NeuAc ${\alpha}$2,3Gal$\beta$ 1,3GalNAc GalNac ${\alpha}$2,6-Sialyltransferase (hST6GalNac IV) was isolated by screening of human fetal liver cDNA library with a DNA probe generated from the cDNA sequence of mouse ST6Gal NAc IV (mkST6GalNAc IV). The cDNA sequence included an open reading frame coding for 302 amino acids, and comparative analysis of this cDNA with mST6GalNAc IV showed that each sequence of the predicted coding region contains 88% and 85% identifies in nucleotide and amino acid levels, respecively. The primary structure of this enzyme suggested a putative domain structure, like that in other glycosyltransferases, consisting of a short N-terminal cytoplamic domain, a transmembrane domain and a large C-terminal active domain. This enzyme expressed in COS-7 cells echibited transferase activity toward NeuAc ${\alpha}$2,3Gal$\beta$ 1,3GalNAc, fetuin and GM1b, although the activity toward the later is very low, no significant activity being detected toward Gal${\beta}$ 1,3Gal NAc or asialofetuin, the other glycoprotein substrates tested. The $^{14}$ C-sialylated residue of fetuin sialylated by this enzyem with CMP-[$^{14}$C]NeuAc was sensitive to treatment with ${\alpha}$2,8-specific sialidase of Vibrio cholerae but resistant to treatment with ${\alpha}$2,3-specific sialidase (NaNase I), and ${\alpha}$2,3- and ${\alpha}$2,8-specific sialidase of Newcastle disease virus. These results clearly indicated that the expressed enzyme is a type of GalNAc ${\alpha}$2,6-sialyltransferase like mST6GalNAc IV, which requires sialic acid residues linked to Gal${\beta}$1,3GalNAc-residues for its activity.

• KSBB Journal
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• v.11 no.4
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• pp.445-452
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• 1996

To investigate the promoter effect on heterologous gene expression in S. cerevisiae, the recombinant plasmids pYI11, pYI12, pYI10-2, and pYIGP were constructed to contain the inulinase gene (INUI) as a reporter under the control of GAL10, GAL7, GAL1, and GAP promoters, respectively. When the yeasts transformants were cultivated on galactose-containing rich media, the cell growth reached to 36-39 OD600 at 72 hours of cultivation. The specific growth rates of the cells harboring the four different plasmids decreased similarly : they dropped from $0.24 h^{-1}$ during the glucose-consuming period to 0.04 -$0.10 h^{-1}$ during the galactose-consuming period (gene expression phase for GAL promoter system). After the depletion of glucose, the expression of inulinase gene was started and reached to maximal levels of 4.3(GAL1 promoter), 4.0(GAL10 promoter), 3.8(GAL7 promoter), and 1.6(GAP promoter) unit/mL at 72 hours of cultivation. Based on the maximal expression level and activity staining on the plate, the promoter strength was in the order of GAL1, GAL10, GAL7 and GAP promoter. While the GAL-promoter systems showed a high plasmid stabilities of more than 78%, the GAP-promoter plasmid revealed a lower plasmid stability of 55%. Most of inulinase activity (98%) was found in the extracellular medium, indicating that the secretion efficiency of inulinase is independent on the type of promoter.

• Journal of Chest Surgery
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• v.41 no.1
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• pp.12-24
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• 2008

Background: It is currently thought that tissue valve degeneration is related to an animal's immune response, which is mainly due to cell surface ${\alpha}$-Gal epitopes. Cell surface ${\alpha}$-Gal epitopes are known to be degraded by the enzyme called green coffee bean ${\alpha}$-Galactosidase. It is also well known that ${\alpha}$-Gal epitopes are immunologically stained by Griffonia Simplicifolia isolectin type B4. We know that many commercially available tissue valves are made of aortic valves and pericardial tissue of pig. So, we investigated whether ${\alpha}$-Gal epitopes of the aortic valve and pericardial tissue of a pig can be removed by green coffee bean ${\alpha}$-Galactosidase, and we did so by comparing immunologic staining of the tissues before and after the enzyme treatment. Material and method: After treating fresh porcine aortic valve and pericardial tissue with green coffee bean ${\alpha}$-Galactosidase at concentrations of 0.5 unit/mL, 1.0 unit/mL, 2.0 unit/mL, respectively, under the condition of pH 6.5, temperature. $4^{\circ}C$ and 24 hours of incubation, each sample was stained with Griffonia Simplicifolia isolectin type B4 immunpfluorescent labeling. We then examined whether the ${\alpha}$-Gal epitopes were reduced or abolished in each consecutive. concentration of green coffee bean ${\alpha}$-Galactosidase by comparing the degree of the Griffonia Simplicifolia isolectin B4 staining in each sample. Result: In the pig aortic valve tissue, a 1.0 unit/mL concentration of green coffee bean ${\alpha}$-Galactosidase at pH 6.5, $4^{\circ}C$ and reaction for 24 hours was enough for complete removal of ${\alpha}$-Gal epitopes from the cell sur face on the immunostaining with Griffonia Simplicifolia isolectin B4. On the other hand, more ${\alpha}$-Gal epitopes were present in the pig pericardial tissue on Griffonia Simplicifolia isolectin B4 staining before the enzyme treatment, and 1.0 unit/mL of galactosidase was not sufficient for complete removal of ${\alpha}$-Gal from the tissue. 2.0 units/mL of green coffee bean ${\alpha}$-Galactosidase was needed to completely remove the ${\alpha}$-Gal epitopes from the pericardial tissue on immunostaining. Conclusion: The ${\alpha}$-Gal epitopes of the pig's aortic valve and pericardial tissue were successfully stained with Griffonia Simplicifolia isolectin B4. We could remove nearly all the ${\alpha}$-Gal epitopes using green coffee bean ${\alpha}$-Galactosidase at the concentration of 1.0 unit/mL in the aortic valve. Of pig, and 2.0 unit/mL was need to nearly completely remove all the ${\alpha}$-Gal epitopes in the pericardial tissue of pig under the condition of pH 6.5, $4^{\circ}C$ and 24 hours of reaction time. In the near future, removal of ${\alpha}$-Gal epitapes in the pig's aortic valve and pericardial tissue will become a powerful tool for the improvement of the tissue valve durability. It needs to be determined if ${\alpha}$-galactosidase treated pig tissue is immune to human anti-Gal antibody or anit-Gal mooclonal antibodies.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.84-89
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• 2019

To characterize the molecular structure of BzO-gal synthesized using Escherichia coli ${\beta}$-gal, NMR ($^1H$- and $^{13}C$-) spectroscopy and mass spectrometry of BzO-gal were conducted. $^1H$ NMR spectrum of BzO-gal showed multiple peaks corresponding to the galactosyl group, which is an evidence of galactosylation on BzOH. Five proton peaks around the aromatic region at ${\delta}_H$ 7.43 ~ 7.24 ppm and 2 peaks from ${\delta}_H$ 4.93 and 4.67 ppm were evidence of the presence of the benzyl group. Seven proton peaks at ${\delta}_H$ 4.32 ~ 3.46 ppm showed the presence of a monosaccharide and were indicative of galactosylation on BzOH. $^{13}C$ NMR spectrum also revealed the presence of 11 carbons suggestive of BzO-gal. The mass value (sodium adduct ion of BzO-gal, m/z = 293.0994) from mass spectrometry analysis of BzO-gal, and $^1H$ and $^{13}C$ NMR spectral data were in good agreement with the expecting structure of BzO-gal. We are expecting that through future study it will eventually be able to develop a new additive of low cytotoxicity.

• Journal of Chest Surgery
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• v.45 no.6
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• pp.380-389
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• 2012

Background: Bovine pericardium is one of the most widely used materials in bioprosthetic heart valves. Immunologic responses have been implicated as potential causes of limited durability of xenogenic valves. This study aimed to determine the effectiveness of decellularization and ${\alpha}$-galactosidase (${\alpha}$-gal) to remove major xenoreactive antigens from xenogenic tissues. Materials and Methods: Recombinant Bacteroides thetaiotaomicron (B. thetaiotaomicron) ${\alpha}$-gal or decellularization, or both were used to remove ${\alpha}$-gal from bovine pericardium. It was confirmed by ${\alpha}$-gal-bovine serum albumin-based enzyme-linked immunosorbent assay (ELISA), high-performance anion exchange chromatography, flow cytometry, 3,3'-diaminobenzidine-staining, and lectin-based ELISA. The mechanical properties of bovine pericardium after decellularization or ${\alpha}$-gal treatment were investigated by tests of tensile-strength, permeability, and compliance. Collagen fiber rearrangement was also evaluated by a 20,000${\times}$ transmission electron microscope (TEM). Results: Recombinant B. thetaiotaomicron ${\alpha}$-gal could effectively remove ${\alpha}$-gal from bovine pericardium B. thetaiotaomicron (0.1 U/mL, pH 7.2) while recombinant human ${\alpha}$-gal removed it recombinant human ${\alpha}$-gal (10 U/mL, pH 5.0). There was no difference in the mechanical properties of fresh and recombinant ${\alpha}$-gal-treated bovine pericardium. Furthermore, the TEM findings demonstrated that recombinant ${\alpha}$-gal made no difference in the arrangement of collagen fiber bundles with decellularization. Conclusion: Recombinant B. thetaiotaomicron ${\alpha}$-gal effectively removed ${\alpha}$-gal from bovine pericardium with a small amount under physiological conditions compared to human recombinant ${\alpha}$-gal, which may alleviate the harmful xenoreactive immunologic responses of ${\alpha}$-gal. Recombinant ${\alpha}$-gal treatment had no adverse effects on the mechanical properties of bovine pericardium.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.68-75
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• 1998

The overproduction and high level secretion of Glucose Oxidase (GOD) from A. niger in S. cerevisiae was carried out by cloning GOD gene. For this purpose, using two different strong promoters (ADH1 promoter, GAL10 promoter) and signal sequences (${alpha}$-MF signal sequence of S. cerevisiae and ${alpha}$-amylase signal sequence of A. oryzae) and GAL7- and GOD terminator, four expression vectors were constructed. All the expression vectors were transformed in S. cerevisiae 2805 using auxotroph method. By the flask culture, transformants of pGAL expression vector series containing GAL 10 promotor showed much higher GOD productivity than transformants of pADH expression vector series containing ADH1 promoter Transformants of pGALGO2 containing GAL10 promotor and ${alpha}$-amylase signal sequence has shown the best productivity of GOD ($GOD_{total}$: 10.3 unit/mL, $GOD_{ex}$: 8.7 unit/mL) at 115 hr. This value was three fold higher than that of pGALGO1 containing GAL 10 promotor and ${alpha}$-MF signal sequence, even if the same promotor was involved. Through the ${alpha}$-amylase signal sequence of A. oryzae, GOD was secreted much more than the case of ${alpha}$-MF signal sequence from S. cerevisiae. These results suggest that signal sequence may play a important roles in not only the secretion but also the overproduction of foreign protein. Secretion rate of GOD in pGALGO1 and pGALGO2 was 89% and 84%, respectively, Because of the overglycosylation in S. cerevisiae the molecular weight of recombinant GOD in S. cerevisiae was much larger (250 kDa) than that of nature GOD in A. niger (170 kDa).

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.826-832
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• 2013

We investigated the transgalactosylation reaction of chlorphenesin (CPN) using ${\beta}$-galactosidase (${\beta}$-gal)-containing Escherichia coli (E. coli) cells, in which galactose from lactose was transferred to CPN. The optimal CPN concentration for CPN galactoside (CPN-G) synthesis was observed at 40 mM under the conditions that lactose and ${\beta}$-gal (as E. coli cells) were 400 g/l and 4.8 U/ml, respectively, and the pH and temperature were 7.0 and $40^{\circ}C$, respectively. The time-course profile of CPN-G synthesis under these optimal conditions showed that CPN-G synthesis from 40 mM CPN reached a maximum of about 27 mM at 12 h. This value corresponded to an about 67% conversion of CPN to CPN-G, which was 4.47-5.36-fold higher than values in previous reports. In addition, we demonstrated by thin-layer chromatography to detect the sugar moiety that galactose was mainly transferred from lactose to CPN. Liquid chromatography-mass spectrometry revealed that CPN-G and CPN-GG (CPN galactoside, which accepted two galactose molecules) were definitively identified as the synthesized products using ${\beta}$-gal-containing E. coli cells. In particular, because we did not use purified ${\beta}$-gal, our ${\beta}$-gal-containing E. coli cells might be practical and cost-effective for enzymatically synthesizing CPN-G. It is expected that the use of ${\beta}$-gal-containing E. coli will be extended to galactose derivatization of other drugs to improve their functionality.