• Applied Biological Chemistry
• /
• v.37 no.1
• /
• pp.49-55
• /
• 1994

An acidic protein, RCG-2, containing chitinase and ${\beta}-1,3-glucanase$ activity conccurrently was purified from rice leaves by chromatofocusing and gel slicing. The purified enzyme gave a single band on polyacrylamide gel electrophoresis and its molecular weight was appeared to be 29.7 kd using SDS-PAGE. This enzyme also had lysozyme activity. The optimal temperature for both enzyme activities was $40^{\circ}C$, optimal pH were 4.0 for chitinase activity and 7.0 for ${\beta}-1,3-glucanase$ activity. $K_M$ and $V_{max}$ values for chitinase were 7.86 mM and $0.025\;{\mu}M/min.$, and those for ${\beta}-1,3-glucanase$ were 5.95 mM and $0.16\;{\mu}M/min.$ respectively. TLC analysis of the enzyme hydrolysates of chitooligosaccharides indicated that this enzyme acts as endochitinase.

• Journal of the Korean Ceramic Society
• /
• v.25 no.3
• /
• pp.261-267
• /
• 1988

$\beta$-Sialon powder was prepared by the reduction-nitridation reaction from the mixture of Wando Pyrophyllite and carbon black at 135$0^{\circ}C$ in $N_2$ atmosphere. $\beta$-SiC powder was added to the prepared $\beta$-Sialon powder to make $\beta$-Sialon-SiC composite. The $\beta$-Sialon-SiC composites were sintered pressurelessly at 175$0^{\circ}C$ for 2h, using $Y_2O_3$ and $ZrO_2$(monoclinic) as sintering aids. Comparatively higher values of the fracture toughness (3.8 MN/㎥/2), M.O.R. (470 MN/$m^2$) and vickers microhardness (13.7 MN/$m^2$) were obtained when 10 wt% $Y_2O_3$ was added as a sintering aid. The improved fracture toughness and M.O.R. are assumed to be the results of crack deflection and crack branching by the second phase SiC particles.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.9
• /
• pp.1513-1520
• /
• 2007

[ ${\beta}$ ]-1,3-Glucans enhance immune reactions such as antitumor, antibacterial, antiviral, anticoagulatory, and wound healing activities. ${\beta}$-1,3-Glucans have various functions depending on the molecular weight, degree of branching, conformation, water solubility, and intermolecular association. The molecular weight of the soluble glucan was about 15,000 as determined by a high-performance size exclusion chromatography. From the infrared (IR) and $^{13}C$ NMR analytical data, the purified soluble glucan was found to exclusively consist of ${\beta}$-D-glucopyranose with 1,3 linkage. We tested the immunestimulating activities of the soluble ${\beta}$-1,3-glucan extracted from Agrobacterium sp. R259 KCTC 1019 and confirmed the following activities. IFN-$_{\gamma}$ and each cytokines were induced in the spleens and thymus of mice treated with soluble ${\beta}$-1,3-glucan. Adjuvant effect was observed on antibody production. Nitric oxide was synthesized in monocytic cell lines treated with ${\beta}$-1,3-glucan. The cytotoxic and antitumor effects were observed on various cancer cell lines and ICR mice. These results strongly suggested that this soluble ${\beta}$-1,3-glucan could be a good candidate for an immune-modulating agent.

• Korean Journal of Pharmacognosy
• /
• v.38 no.4
• /
• pp.376-381
• /
• 2007

Seven compounds were isolated from the MeOH extract of the seeds of Plantago asiatica L. and their structures were identified as ${\beta}-sitosterol$ (1), (24R)-6${\beta}$-hydroxy-24-ethyl-cholest-4-en-3-one (2), acteoside (3), geniposidic acid (4), 1-octen-3-ol 3-O-${\beta}$-D-xylopyranosyl$(1{\rightarrow}6)-{\beta}-D-glucopyranoside$ (5), plantainoside D (6) and plantamajoside (7) on the spectroscopic analysis. Among them, $(24R)-6{\beta}$-hydroxy-24-ethyl-cholest-4-en-3-one (2) and 1-octen-3-ol 3-O-${\beta}$-D-xylopyranosyl ($1{\rightarrow}6)-{\beta}-D-glucopyranoside$ (5) were first isolated from this plant. Among them, geniposidic acid (4) showed the most potent inhibitory effect on melanogenesis, with inhibition rate of 41%.

• Korean Journal of Medicinal Crop Science
• /
• v.14 no.5
• /
• pp.273-277
• /
• 2006

Three stigmastane-type sterols and one ergostane-type sterol were isolated from the ethyl acetate soluble fraction of the aerial parts of Artemisia princeps Pampanini (Sajuarissuk). From the results of physico-chemical data including NMR, MS and IR, the chemical structures of the compounds were determined as $stigmasta-5,22-dien-3,{\beta}-ol (stigmasterol, 1),stigmast-5-en-3{\beta}-ol({\beta}-sitosterol,2), 5{\beta},8{\beta}-epidioxy-5{\beta},8{\beta}-ergosta-6,22-dien-3{\beta}-ol(ergosterol peroxide, 3),\;and\;{\beta}-sitosterol\;3-O-{\beta}D-glucopyranoside(daucosterol,4)$.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.2
• /
• pp.314-319
• /
• 2001

In the present study, effects of $\beta$-alanine, a known taurine antagonist for its structural similarity, on the adaptive regulation and kinetic behavior of the taurine transporter were investigated in the HT-29, human colon carcinoma cell line. Pretreatment of the cell with $\beta$-alanine(10mM) for varying periods from 3 to 30 hrs significantly reduced the taurine uptake compared to the value for control cells. This decrease in the taurine transporter activity was dependent on the incubation time with $\beta$-alanine, and the maximal down-regulation of the transporter activity was observed in cells pretreated with $\beta$-alanine for 24 hrs (25% of the control value, p<0.01). The taurine transporter appears to bind exclusively with $\beta$-alanine in the HT-29 cells since the same concentration of $\alpha$-alanine added in the culture medium for 24 hrs did not influence the taurine uptake. Kinetic analyses of the taurine transporter activity was performed in the HT-29 cell line with varying taurine concentration (5~60$\mu$M) in the uptake medium. Active taurine uptake was significantly lower in $\beta$-alanine pretreated cells compared to the value for control cells in the range of taurine concentration used in the experiment (p<0.001). The cells pretreated with $\beta$-alanine showed a 50% lower maximal velocity (Vmax, 1.7$\pm$2.0 nmole.mg $protein^{-1}$.$30min^{-1}$), and a 99% higher Michaelis constant (Km, 40.3$\pm$7.6$\mu$M) than the control values (3.3$\pm$1.9 nmole.mg $protein^{-1}$.$30min^{-1}$, and 20.3$\pm$2.1$\mu$M, respectively). These results on kinetic data suggest that $\beta$-alanine induced down-regulation of the taurine transporter activity was associated with decreases in both maximal velocity and affinity of the transporter.

• Bulletin of the Korean Chemical Society
• /
• v.8 no.4
• /
• pp.257-260
• /
• 1987

The asymmetric reduction of representative prochiral ${\alpha},{\beta}$-acetylenic ketones with a new chiral borohydride reducing agent, potassium 9-0-(1,2: 5,6-Di-O-isopropylidene-${\alpha}$ -D-glucofuranosyl)-9-boratabicyclo[3.3.1]nonane, 1, in THF at $-78^{\circ}C$ was studied. Structurally different acetylenic ketones such as internal ${\alpha},{\beta}$-acetylenic ketones $RC {\equiv} CCOCH_3$ and terminal ${\alpha},{\beta}$-acetylenic ketones $HC {\equiv} CCOR$ were chosen. Thus, the reduction of internal ${\alpha},{\beta}$-acetylenic ketones yields the corresponding propargyl alcohols, such as 67% ee for 3-hexyn-2-one, 75% ee for 5-methyl-3-hexyn-2-one, 86% ee for 5,5-dimethyl-3-hexyn-2-one, 74% ee for 3-nonyn-2-one and 61% ee for 4-phenyl-3-butyn-2-one. Terminal ${\alpha},{\beta}$-acetylenic ketones, such as 3-butyn-2-one, 1-pentyn-3-one, 4-methyl-1-pentyn-3-one and 1-octyn-3-one, are reduced to the corresponding alcohols with 59% ee, 17% ee, 44% ee and 12% ee of optical induction respectively. With one exception (4-methyl-1-pentyn-3-one), all propargyl alcohols obtained are enriched in R-enantiomers.

• Journal of Veterinary Clinics
• /
• v.11 no.1
• /
• pp.389-392
• /
• 1994

To purify transforming growth factor type beta(TGF-$\beta$) in canine platelets, Sephadex G-75 gel filtration and semipreparative HPLC were carried out. The column of $2.0 {\times}120cm$ was used for gel filtration and one inch semipreparative column filled with SP-Toyopeal for HPLC. Electrophoresis and bioassay using African green monkey kidney cell were used for identification of TGF-$\beta$ Crude TGF-$\beta$ of 2.75mg was extracted from 5.2g of the platelets by the treatment of acid/ethanol. In gel filtration of crude TGF-$\beta$, 4 peaks were observed at the detection of spectrophotometer at 280nm. Electrophoresis and bioassay identified the 3rd peak TGF-$\beta$. Linear gradient elution from 0 to 3M NaCl in sornipreparative HPLC showed TGF-$\beta$ at 1.5M NaCl. Gel filtration was less expensive and useful method for the purification of TGF-$\beta$.

• The Korean Journal of Physiology and Pharmacology
• /
• v.13 no.4
• /
• pp.273-279
• /
• 2009

The accumulation of ${\beta}$-amyloid (A${\beta}$) aggregates is a characteristic of Alzheimer's disease (AD). Furthermore, these aggregates have neurotoxic effects on cells, and thus, molecules that inhibit A${\beta}$ aggregate formation could be valuable therapeutics for AD. It is well known that aggregation of A${\beta}$ depends on its hydrophobicity, and thus, in order to increase the hydrophilicity of A${\beta}$, we considered using citrate, an anionic surfactant with three carboxylic acid groups. We hypothesized that citrate could reduce hydrophobicity and increase hydrophilicity of A${\beta}_{1-40}$ molecules via hydrophilic/electrostatic interactions. We found that citrate significantly inhibited A${\beta}_{1-40}$ aggregation and significantly protected SH-SY5Y cell line against A${\beta}_{1-40}$ aggregates-induced neurotoxicity. In details, we examined the effects of citrate on A${\beta}_{1-40}$ aggregation and on A${\beta}_{1-40}$ aggregates-induced cytotoxicity, cell viability, and apoptosis. Th-T assays showed that citrate significantly inhibited A${\beta}_{1-40}$ aggregation in a concentration-dependent manner (Th-T intensity: from 91.3% in 0.01 mM citrate to 82.1% in 1.0 mM citrate vs. 100.0% in A${\beta}_{1-40}$ alone). In cytotoxicity and viability assays, citrate reduced the toxicity of A${\beta}_{1-40}$ in a concentration-dependent manner, in which the cytotoxicity decreased from 107.5 to 102.3% as compared with A${\beta}_{1-40}$ aggregates alone treated cells (127.3%) and the cell viability increased from 84.6 to 93.8% as compared with the A${\beta}_{1-40}$ aggregates alone treated cells (65.3%). Furthermore, Hoechst 33342 staining showed that citrate (1.0 mM) suppressed A${\beta}_{1-40}$ aggregates-induced apoptosis in the cells. This study suggests that citrate can inhibit A${\beta}_{1-40}$ aggregation and protect neurons from the apoptotic effects of A${\beta}_{1-40}$ aggregates. Accordingly, our findings suggest that citrate administration should be viewed as a novel neuroprotective strategy for AD.

• Journal of the Korean Magnetic Resonance Society
• /
• v.10 no.1
• /
• pp.89-95
• /
• 2006

The methanolic extract of the marine sponge Raspilia hirsute collected from Keomun Island resulted in three types of sterols: a mixture of (24S)-Poriferasta-5, 25-diene-$3\beta$, 24-diol and (24R)-Stigmasta-5, 25-diene-$3\beta$, 24 -diol (1), 25,26,27-Trinorcholest-5-en-$3\beta$,24-diol (2), and Pregn-5-en-20-on-$3\beta$-ol (3). The isolation and structural determination of these sterols are reported here. Compound 1 showed moderate cytotoxicity against human Leukemia cell line K562.