• Korean Journal of Food Science and Technology
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• v.47 no.3
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• pp.286-292
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• 2015

We developed a rapid isolation method for fractionation of polysaccharides with different characteristics, and optimized it for the polysaccharide mixture from Korean citrus peels. A crude polysaccharide mixture, citrus-peel-enzyme (CPE) fraction was isolated from the citrus peels digested with pectinase and ethanol precipitation. CPE was further fractionated with serially diluted ethanol solution (ethanol:deionized water=8:1, 4:1, 3:1, 2:1, 1.5:1, 1:1, and 0.5:1) to produce seven fractions labeled from CPE8 to CPE0.5. Fraction from CPE8 to CPE1 were mostly composed of 11 different sugars, including rhamnogalacturonan (RG) I and II, and the sugars contained arabino-${\beta}$-3,6-galactan moiety. However, CPE0.5 did not contain RG-II and arabino-${\beta}$-3,6-galactans. Treatment of macrophages with fractions CPE8-CPE1 led to a dose-dependent increase in interleukin-6 production (IL-6), while treatment with CPE1 and CPE0.5 fractions resulted in decreased levels of IL-6. These results indicate that this isolation method may be useful for the rapid fractionation of bioactive RGs from polysaccharide mixtures.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.136-144
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• 1989

The purification of myrosinase from radish roots was performed using Concannavalin A-Sepharose affinity chromatography and gel permeation HPLC, which gave a 22-fold-purification(S.P.A.=39,000 units/mg) with 50% recovery, SDS-polyacrylamide gel electrophoresis showed a single major band, suggestive of a relatively pure myrosinase, and the M.W. of the enzyme determined on gel permeation HPLC was ca. 124K. The enzyme showed on optimum pH of 6.5 and was stable at pH 6 to 7 at room temperature, but unstable below pH 4. The enzyme possessed an optimum temperature of $37^{\circ}C$, and gave a Vmax value of $40\;{\mu}moles/mg{\cdot}min$ and a Km value of 0.12mM for sinigrin. The purified myrosinase was activated maximally by 0.6mM of ascorbic acid, but somewhat inhibited by more than 2 mM ascorbic acid. The activities of myrosinase present in the peelings and the peeled radish amounted to approximately 1,333 units/g and 140 units/g weight, respectively and the peelings contained much more myrosinase activity than the peeled radish.

• The Korean Journal of Mycology
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• v.17 no.2
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• pp.66-75
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• 1989

Heterogeneity in antigenic composition of Aspergillus fumigatus isolates from clinical specimens and in antibody response of patients infected with this fungus was investigated by immunoblotting. A considerable quantitative and qualitative difference was found in composition of the culture filtrate antigens derived from a reference strain (ATCC 13073) and 8 clinical isolates of A. fumigatus on SDS-PAGE and immunoblots. The crude CF antigen of a strain AFG7 was selected to identify the serologically reactive and specific components by immunoblotting. Out of more than 36 components separated by electrophoresis, transblotted to nitrocellulose sheet, and reacted with sera that showed a positive reaction to A. fumigatus or other fungal antigens on immunodiffusion tests, merely four or so were found useful to serodiagnosis of aspergillosis. An antigen of 82KD was found most reactive and specific component so as to be contained in the standard preparation. Several other components, for example 11KD, 26KD, 30KD and 31KD, also possessed relatively high reactivity and specificity and seemed to be worth while purifying and characterizing. Antibody binding activity (reactivity) of the antigenic components was clearly shown on immunoblots because some were faintly stained with Coomassie blue but darkly stained on immunoblots, while some others behaved contrary to them. A number of components seemed to carry not only species specific but cross reactive antigenic determinants. Immunoblotting proved very useful to identify serologically reactive and specific components that should be present in the antigen to be employed to the serodiagnosis of aspergillosis.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.316-323
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• 1992

Studies on the changes in rheological properties, molecular weight distribution and dextran yield after being reacted in lO%(w/w) sucrose concentration were performed with crude dextransucrase produced from Leuconostoc mesenteroides isolated from Sikhae. The reaction rate of dextran formation was monitored by sugar analysis with HPLC and by the changes in apparent viscosity. According to the periodate oxidation test, the dextran produced in this experiment was estimated to have 89% $\alpha$-(1->6) main linkages and 11% $\alpha$-(1->) side linkages. The rheological properties of the dextran solution formed changed with reaction time, and it was related to the changes in molecular weight distribution of dextran as determined by GPC analysis. As the reaction proceeded, the rheological behavior changed from Newtonian to non-Newtonian, showing Binghampseudoplastic and thixothropic flow behavior. The apparent viscosity of dextran formed solution increased with increasing reaction time, reached a maximum value of 2680 cP ($\gamma$=$33.75s^{-1}$, $25^{\circ}C$) by enzyme reaction for 8 hours, and then decreased. The temperature dependency of dextran formed solutions was well expressed by the Arrhenius equation and the activation energy reached a maximum value of 1.69 kcal/mole by enzyme reaction for 8 hours.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.637-644
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• 1998

[ $\beta$ ]-Galactosidase was extracted from the internal organ of sea urchin, Hemicentrotus pulcherrimus The enzyme was purified 384.6-fold over the crude extract by the sequential chromatographic methods including DEAE-Sephadex A-25, CM-Cellulose, and Con A-Sepharose 4B affinity chromatography with a recovery $1.26\%$. The molecular weight of the purified enzyme was estimated approximately 94 kDa as monomeric term by SDS-PAGE and Sephadex G-150 gel chromatography. The maximum enzymatic activity was observed at pH 3.0 and $50^{\circ}C$ but the one was stable over the ph range or 3.0$\~$5.0 and below $37^{\circ}C$. The $K_m$ and $V_{max}$ values against PNPG (P-nitrophenyl $\beta$-D-galactopyranoside) were 15.0 mM and 214 $\mu$mole/min per mg protein, respectively. The enzymatic activity was activated by $Ba^{2+}$, but significantly inhibited by $DEP,\;Hg^{2+},\;Sn^{2+}$ and galactose.

• Korean Journal of Ichthyology
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• v.27 no.4
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• pp.284-292
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• 2015

Monthly variation of species composition and abundance of fish eggs were examined to know the spawning time and location of the fishes inhabiting the coastal region of Jejudo Island. Samplings had been performed at the four locations (Jeju port, Seongsanpo, Seogwipo port and Chagwido) with a bongo net which was towed monthly at the sea surface from August 2006 to July 2007. The fish eggs were identified based on phylogenetic analyses with the DNA sequences generated through PCR-amplification and sequencing of the mitochondrial cytochrome b gene. Among a total of 43 taxa classified during the study period, 34 were identified to species, 4 to families, and the remaining 5 were unidentified. Of them, 23 taxa were occurred at Jeju port, 21 at Seongsanpo, 19 at Seogwipo port and 18 at Chagwido, whereas 15 taxa were found in September 2006, 12 in June 2007, 6 to 8 in August 2006 and January~May 2007, 5 in each October and November 2006, 3 in each December 2006 and July 2007. Among 34 species of fish eggs, Engraulis japonicus and Callanthias japonicus most frequently appeared at 16 times out of 48 observations in total. When those eggs were collected, the surface seawater temperature ranged $14.0{\sim}28.6^{\circ}C$ for E. japonicus and $14.9{\sim}20.5^{\circ}C$ for C. japonicus. The success rates of PCR-amplification and species identification in this study were 68.3% and 79.1%, respectively.

• Polymer(Korea)
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• v.32 no.3
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• pp.246-250
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• 2008

Colloidal stability of the biodegradable nanoparticle was characterized by measuring the variation of particle size with time using photon correlation spectroscopy. Three kinds of polymers, namely, poly(D,L-lactide-co-glycolide)(PLGA), PLGA/poly(L-lactide) blends, and PLGA/poly(L-lactide)-g-poly(ethylene glycol) blends were used as matrix material for nanoparticle preparation. Nanoparticles were prepared with or without using poly(vinyl alcohol)(PVA) as suspension stabilizer to evaluate the condition of preparation. Nanoparticles from the blend of amphiphilic graft copolymer with short poly(ethylene glycol) chain and PLGA maintained suspension for 1 day when protein stock solution was introduced. This is somewhat improvement in colloidal stability against protein adsorption compared with that of nanoparticles without PEG moiety. Suspension stabilizer, PVA, had a significant effect on the colloidal stability against freezing and protein adsorption which led to coagulation of nanoparticles. It is important to consider effect of suspension stabilizer as well as materials used to prepare nanoparticle on the colloidal stability.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.624-632
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• 1989

Lipids of Liza carinata roe were extracted and separated into detailed lipid classes by column chromatography. About 57-62% of the total lipids consisted of wax esters in which saturated and unsaturated fatty alcohols combined with fatty acids with up to six double bonds. Between the even-numbered wax ester peaks in gas-liquid chromatography, ones with odd chain lengths such as C31, C33 and C35 were eluted in appreciable amounts. Isomers composed of different fatty acids and alcohols at a given chain length were not resolved on 1.5% OV-17 column. The principal component of wax esters in sample A were C32, C34 and C30 (45.0%, 19.2%, and 12.2%), followed by C36 and C38 length (9.5% and 4.7%), while those in sample B were mainly occupied by C34, C32 and C36 length (36.3%, 31.4% and 14.5%) with minor components C30 and C38 length (5.2%, and 3.4%). The wax esters were not a random combination of constituent fatty acids and alcohols. With increase in boiling temperature the wax esters increased slightly in viscosity over the unboiled, showing a tendency toward randomness, and finally were completely randomized at $360^{\circ}C$ for 40 minutes. The enzymes involved in wax ester biosynthesis seemed to have high selectivity for chain length of fatty acids and alcohols.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.565-573
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• 2010

Thinning of apple fruitlets is one of the most laborious and important works for the improvement of fruit quality and for the promotion of sufficient flower bud formation to prevent alternate bearing in commercial cultivars. Lateral fruits of self-thinning apple cultivars fall naturally within 30 days after full bloom and only central fruit remains to mature. Differences of gene expression between central fruit and lateral fruit were investigated by differential display (DD) PCR. Partial cDNAs of 30 clones from the central fruit and 24 clones from the lateral fruit were selected for nucleotide sequence determination and homology searches. The levels of transcripts coding for proteins involved in pathogenesis related proteins, senescence, temperature stress, protein degradation, fruit browning, sorbitol metabolism were significantly higher in pedicels of lateral fruit than in pedicels of central fruit. On the other hand, the up-regulation of proteins involved in anthocyanin and flavanol biosynthesis and ethylene synthesis were observed in pedicels of central fruit. In Real time PCR analysis, cytochrome P450 gene was confirmed as showing a higher expression level in lateral fruit than in central fruit. The results of this study indicate that differentially expressed genes are related to self-thinning characteristics in apple tree.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.652-656
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• 2018

In this study, effects of the reaction pressure were studied for petroleum-based pitch synthesis. A two-stage reaction process was performed based on different reaction pressure conditions. Each stage experiments for the two-stage reaction were consecutively carried out. The first stage was consisted of three different pressure conditions; high (10 bar), normal and low (0.1 bar). And the second stage was carried out at the normal and low (0.1 bar) pressure. The pitch synthesis was realized at $400^{\circ}C$ for 2 h. Thermal properties and molecular weight distributions of each samples were investigated by analyzing the softening point and MALDI-TOF data. Volatilized components during the pith synthesis were measured by GC-SIMDIS. In case of the first-step reaction with the high pressure condition, the low molecular weight component participated to the pitch formation more effectively and the pitch with the low softening point was obtained. However, for the case of the first-step with the low pressure, the low molecular weight component was vent outside and the partial coke formation occurred. Eventually, pitch properties such as the softening point and yield were controlled effectively by changing the pressure in the pitch synthesis reaction.