• Bulletin of the Korean Chemical Society
• /
• v.28 no.2
• /
• pp.347-350
• /
• 2007

• Journal of Microbiology and Biotechnology
• /
• v.9 no.6
• /
• pp.704-708
• /
• 1999

In addition to catalyzing the synthesis of glucan from sucrose as a primary reaction, glucansucrase also catalyzes the transfer of glucose from sucrose to other carbohydrates that are present or are added to the reaction digest. Using dextransucrase and altemansucrase, prepared from Leuconostoc mesenteroides B-742CBM and B-1355C, respectively, we modified the bacterial cellulose in Acetobacter xylinum ATCC10821 culture, and then produced a characteristic cellulose that is soluble and has a new structure. There were also some partially modified insoluble cellulose and oligosaccharides in the modification culture. After methylation and following acid hydrolysis of both the soluble and insoluble glucans, there were ($1{\rightarrow}4$) as well as ($1{\rightarrow}6$) and ($1{\rightarrow}3$) glycosidic linkages in the soluble glucan.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.3
• /
• pp.457-464
• /
• 2008

An extracellular enzyme (RMEBE) possessing ${\alpha}-(1{\rightarrow}4)-(1{\rightarrow}6)$-transferring activity was purified to homogeneity from Rhodothermus marin us by combination of ammonium sulfate precipitation, Q-Sepharose ion-exchange, and Superdex-200 gel filtration chromatographies, and preparative native polyacrylamide gel electrophoresis. The purified enzyme had an optimum pH of 6.0 and was highly thermostable with a maximal activity at $80^{\circ}C$. Its half-life was determined to be 73.7 and 16.7 min at 80 and $85^{\circ}C$, respectively. The enzyme was also halophilic and highly halotolerant up to about 2M NaCl, with a maximal activity at 0.5M. The substrate specificity of RMEBE suggested that it possesses partial characteristics of both glucan branching enzyme and neopullulanase. RMEBE clearly produced branched glucans from amylose, with partial ${\alpha}-(1{\rightarrow}4)$-hydrolysis of amylose and starch. At the same time, it hydrolyzed pullulan partly to panose, and exhibited ${\alpha}-(1{\rightarrow}4)-(1{\rightarrow}6)$-transferase activity for small maltooligosaccharides, producing disproportionated ${\alpha}-(1{\rightarrow}6)$-branched maltooligosaccharides. The enzyme preferred maltopentaose and maltohexaose to smaller maltooligosaccharides for production of longer branched products. Thus, the results suggest that RMEBE might be applied for production of branched oligosaccharides from small maltodextrins at high temperature or even at high salinity.

• Korean Journal of Food Science and Technology
• /
• v.48 no.3
• /
• pp.296-300
• /
• 2016

The effect of different temperatures (45, 55, 65, and $75^{\circ}C$) on the extraction of ${\beta}$-glucan and the properties of extracted ${\beta}$-glucan were investigated with four different varieties of barley. Jeju naked barley, blue barley, beer barley, and black barley contained 6.85, 5.13, 3.58, and 4.16% of ${\beta}$-glucan, respectively. ${\beta}$-glucan in barley was extracted in the range of 64.88 to 93.84% depending on the extraction temperature and barley variety. The ${\beta}$-glucans in Jeju naked barley, Jeju blue barley, and black barley were optimally extracted at $65^{\circ}C$ for 3 h and Jeju beer barley at $75^{\circ}C$. The extracted ${\beta}$-glucan resolubilized to 43.48-81.73% and the ratio of ${\beta}(1{\rightarrow}3)$ to ${\beta}(1{\rightarrow}4)$ linkage was in the range of 1:3.8-5.8. These results suggest that purification and properties of ${\beta}$-glucan depend not only on the water extraction temperature, but also on the barley variety.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.6
• /
• pp.1338-1342
• /
• 2004

Cyclosophoraoses (Cys), cyclic ${\beta}-(1{\rightarrow}2)-D-glucans$ produced by Rhizobium meliloti 2011, were used as a novel chiral stationary phase for the enantiomeric separation. A novel Cys stationary phase, chemically immobilized onto porous silica via aminopropyltrimethoxysilane as a molecular linker, showed good separation for each racemate of bupivacain (separation factor, $\alpha$=1.3), propranolol ($\alpha$=1.3), and fenoprofen ($\alpha$=2.9), respectively, under the mobile phase of water: methanol (80:20, v/v) at a constant flow rate of 0.9 ml/min at pH7.

• Korean Journal of Microbiology
• /
• v.42 no.4
• /
• pp.319-325
• /
• 2006

[ $\beta$ ]-Glucans (AG) were prepared from Agaricus blazei cultured in the medium fortified with the roots of Pueraria spp. by repeated extraction with hot water, gel filtration chromatography and DEAE ion exchange chromatography. Oligosaccharides (AO) were derived from the hydrolysis of AG by an endo-$\beta$-(1$\rightarrow$6)-glucanase from Bacillus megaterium. The anti-HT-29 human colon cancer activity of AG or AO was investigated using MTT assay, apoptosis assay, cell cycle analysis, and cDNA microairay. AG and AO both inhibited proliferation and growth of HT-29 cells, and stimulated apoptosis of the cells in a dose-dependent manner. In cell cycle analysis, treating HT-29 cells with AG or AO resulted in the increase of cells in the G0 (sub-G1) and G1 phase. Especially, AO was more effective in inducing G0/G1 cell cycle arrest than AG. To screen the genes involved in the increase of apoptosis, the gene expression profile of the HT-29 cells treated with AO was examined by cDNA microarray. While several genes involved in cell cycle progression (CCND2 and CDK2) were down-regulated, many genes involved in apoptosis (TNFSF9, TNFRSF9, FADD, CASP8, BAD, CRADD, CASP9 etc), cell cycle inhibitor (CDKN2A), immune response (IL6, IL18, IL6R etc), and tumor suppressor (CEACAM1, TP53BP2, IRF1, and PHB) were up-regulated. These results suggest that AO could inhibit the proliferation and growth of HT-29 cells by G0/G1 cell cycle arrest and induction of apoptosis.

• The Korean Journal of Mycology
• /
• v.27 no.1 s.88
• /
• pp.76-81
• /
• 1999

Exo-polysaccharide obtained from the submerged cultivation of Ganoderma lucidum mycelium was fractionated. The structural analysis of the acidic exo-polysaccharide fraction (BWS-DA-GI), showing high antitumor activity, was carried out and compared to the mycelial acidic fraction (MWS-DA-GI). The major sugar constituents of the fraction of BWS-DA-GI were glucose, galactose and mannose in the molar ratio of 2.5 : 2.1 : 2.5. The minor components in this fraction were xylose and fucose. While the major sugar constituents of the mycelial acidic fraction of MWS-DA-GI were galactose, fucose, mannose and glucose. The trace components in this fraction was xylose. From the results of periodate oxidation, Smith degradation, affinity chromatography and methylation analysis, the chemical structures of the two fractions, BWS-DA-GI and MWS-DA-GI were both determined as ${\beta}-1,3$ glucans. It was also estimated that BWS-DA-GI had a $1{\rightarrow}6$ glucosidic linkage and MWS DA-GI had $1{\rightarrow}4$ and $1{\rightarrow}6$ glucosidic linkages. The molecular weights of these fractions, MWS-DA-GI and MWSDA-GI were estimated as $1.2{\times}10^6\;and\;1.0{\times}10^6$ dalton, respectively.