• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1064-1071
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• 2022

Arabinogalactans have diverse biological properties and can be used as pharmaceutical agents. Most arabinogalactans are composed of β-(1→3)-galactan, so it is particularly important to identify β-1,3-galactanases that can selectively degrade them. In this study, a novel exo-β-1,3-galactanase, named PoGal3, was screened from Penicillium oxalicum sp. 68, and hetero-expressed in P. pastoris GS115 as a soluble protein. PoGal3 belongs to glycoside hydrolase family 43 (GH43) and has a 1,356-bp gene length that encodes 451 amino acids residues. To study the enzymatic properties and substrate selectivity of PoGal3, β-1,3-galactan (AG-P-I) from larch wood arabinogalactan (LWAG) was prepared and characterized by HPLC and NMR. Using AG-P-I as substrate, purified PoGal3 exhibited an optimal pH of 5.0 and temperature of 40℃. We also discovered that Zn²⁺ had the strongest promoting effect on enzyme activity, increasing it by 28.6%. Substrate specificity suggests that PoGal3 functions as an exo-β-1,3-galactanase, with its greatest catalytic activity observed on AG-P-I. Hydrolytic products of AG-P-I are mainly composed of galactose and β-1,6-galactobiose. In addition, PoGal3 can catalyze hydrolysis of LWAG to produce galacto-oligomers. PoGal3 is the first enzyme identified as an exo-β-1,3-galactanase that can be used in building glycan blocks of crucial glycoconjugates to assess their biological functions.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.1009-1017
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• 2004

Sialyltransferases cloned so far show the remarkable tissue-specific expression, which is correlated with the existence of cell type-specific sialylated sugar structure in glycoconjugates. In the previous studies, we found various mRNA isoforms of human sialyltransferases generated by alternative splicing and alternative promoter utilization. To understand the regulatory mechanisms for specific expression of human sialyltransferase genes and for production of their mRNA isoforms, in this study, we have isolated and characterized five kinds of human sialyltransferase genes: hST3Gal II, hST8Sia II, hST8Sia III, hST8Sia IV, and hST8Sia V. The hST3Gal II gene is composed of six exons, which span over 17kb, with exons ranging in size from 46 to over 1017 bp. The hST8Sia III gene comprises over 10 kb, and consists of only four exons, which is much smaller and simpler than other human sialyltransferase genes. In contrast, three genes (hST8Sia II, hST8Sia IV and hST8Sia V) span more than 70 kb, and comprise five or more exons. All exon-intron boundaries follow the GT-AG rule. In particular, the sialylmotif L, which is a highly conserved region in all cloned sialyltransferases, was found in one exon of hST8Sia III, whereas this motif is encoded by discrete exons in the other human sialyltransferases. Exon structures of these sialyltransferase genes show the structural diversity, as found in other human sialyltransferase genes reported so far. We determined the transcription start site of hST3Gal II gene by the 5'-RACE and cap site hunting experiments.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.655-659
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• 1998

Bacterial strain showing the strong fibrinolytic activity (2.04 plasmin unit) was screened from Jeot-Gal, Korean salt-fermented fish collected from various region. For the identification, when the strain was characterized morphologically, culturally, and biochemically, it was identified to Bacillus pumilus. And, when the fatty acids composition of the strain was analyzed, it was identified to Bacillus atropheus. Finally, the 16S rRNA partial sequence (V3 region) showed that the fibrinolytic stain screened from Jeot-Gal was identified as Bacillus subtilis. So, we named it Bacillus subtilis KJ-48.

• Proceedings of the Korean Magnestics Society Conference
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• 2016.05a
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• pp.58-58
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• 2016

• Proceedings of the Korean Magnestics Society Conference
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• 2016.05a
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• pp.60-60
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• 2016

• Annals of Clinical Neurophysiology
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• v.13 no.1
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• pp.54-57
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• 2011

The Guillain-Barre Sydrome (GBS) is post-infectious autoimmune disease and it could be caused by auto-antibodies produced after infections. Mycoplasma pneumoniae is one of rare cause of GBS and known to be associated with antibody to galactocerebroside (GalC) which is a major neutral glycolipid constituent of myelin. We report a case of GBS with immunoglobulin M GalC antibody after M. pneumoniae infection.

• Proceedings of the Korean Magnestics Society Conference
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• 2015.11a
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• pp.63-64
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• 2015

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.14-23
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• 2002

Development of oligodendrocytes and the generation of myelin internodes within the spinal cord depends on regional signals derived from the notochord and axonally derived signals. Neuregulin (NRG)-1, localized in the floor plate as well as in motor and sensory neurons, is necessary for normal oligodendrocyte development. Oligodendrocytes respond to NRGs by activating members of the erbB receptor tyrosine kinase family. Here, we show that erbB2 is not necessary for the early stages of oligodendrocyte precursor development, but is essential for proligodendroblasts to differentiate into galactosylcerebroside-positive (GalC+) oligodendrocytes. In the presence of erbB2, oligodendrocyte development is normal. In the absence of erbB2 (erbB2-/-), however, oligodendrocyte development is halted at the proligodendroblast stage with a >10-fold reduction in the number of GalC+ oligodendrocytes. ErbB2 appears to function in the transition of proligodendroblast to oligodendrocyte by transducing a terminal differentiation signal, since there is no evidence of increased oligodendrocyte death in the absence of erbB2. Furthermore, known survival signals for oligodendrocytes increase oligodendrocyte numbers in the presence of erbB2, but fail to do so in the absence of erbB2. Of the erbB2-/- oligodendrocytes that do differentiate, all fail to ensheath neurites. These data suggest that erbB2 is required for the terminal differentiation of oligodendrocytes and for development of myelin.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.3
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• pp.76-87
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• 1993

We present a self-consistent, 2-dimensional solution of the Poisson and Sch rodinger equation based on the finite difference method with a nonuniform mesh size for a AlGaAs/GaInAs/GaAs HEMT devide. During the interative self-consistent calculation, however, we calculate Schrodinger equation only a some region of device, not a fully region in order to save the moemory and the speed-up of computation, and then use the approximated data for the other region using by a interpolation method with a given values. Also we adopt the proper matrix transformation method that allows preservation of the symmetric, form of the discretized Schrodinger equation, even with the use of a nonumiform mesh size, therefor, can reduce the computation time. We calculate the wavefunction, eigenstates and the electron concentration uat channel layer nder the thermal equilibrium and the biased conditions, respectively. Also,these parameters are used to solve 2-dimensional tdistribution of potential in he entire region of device. It is proved that the method is very efficient in finding eigenstages extending over relatively large spatial area without loss of accuracy. So, it can be used rather easily in any sarbitrary modulation doped utucture.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.88-95
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• 2010

An airborne gravity survey using a helicopter was carried out in October 2008, offshore along the northern Noto Peninsula, to understand the shallow and regional underground structure. Eleven flight lines, including three tie lines, were arranged at 2 km spacing within 20 km of the coast. The total length of the flight lines was ~700 km. The Bouguer anomalies computed from the airborne gravimetry are consistent with those computed from land and shipborne gravimetry, which gradually decrease in the offshore direction. So, the accuracy of the airborne system is considered to be adequate. A local gravity low in Wajima Bay, which was already known from seafloor gravimetry, was also observed. This suggests that the airborne system has a structural resolution of ~2 km. Reduction of gravity data to a common datum was conducted by compiling the three kinds of gravity data, from airborne, shipborne, and land surveys. In the present study, we have used a solid angle numerical integration method and an iteration method. We finally calculated the gravity anomalies at 300 m above sea level. We needed to add corrections of 2.5 mGals in order to compile the airborne and shipborne gravity data smoothly, so the accuracy of the Bouguer anomaly map is considered to be nearly 2 mGal on the whole, and 5 mGals at worst in limited or local areas.