• Macromolecular Research
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• v.15 no.5
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• pp.437-442
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• 2007

Poly(ethylene glycol) methyl ether (PEG)-poly(${\beta}$-amino ester) (PAE) block copolymers were synthesized using a Michael-type step polymerization, and the construction of pH-sensitive polymeric micelles (PM) investigated. The ${\beta}$-amino ester block of the block copolymers functioned as a pH-sensitive moiety as well as a hydrophobic block in relation to the ionization of PAE, while PEG acted as a hydrophilic block, regardless of ionization. The synthesized polymers were characterized using $^1H-NMR$, with their molecular weights measured using gel permeation chromatography. The $pK_b$ values of the pH-sensitive polymers were measured using a titration method. The pH-sensitivity and critical micelle concentration (CMC) of the block copolymers in PBS solution were estimated using fluorescence spectroscopy. The pH dependent micellization behaviors with various bisacrylate esters varied within a narrow pH range. The critical micelle concentration at pH 7.4 decreased from 0.032 to 0.004 mg/mL on increasing the number of methyl group in the bisacrylate from 4 to 10. Also, the particle size of the block copolymer micelles was determined using dynamic light scattering (DLS). The DLS results revealed the micelles had an average size below 100 nm. These pH-sensitive polymeric micelles may be good carriers for the delivery of an anticancer drug.

• Macromolecular Research
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• v.16 no.6
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• pp.510-516
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• 2008

New antitumor active polymers, poly(methacryloyl-2-oxy-1,2,3-propanetricarboxylic acid-co-exo-3,6-epoxy-l,2,3,6-tetrahydrophthalic acid) [poly(MTCA-co-ETAc)], poly(methacryloyl-2-oxy-l,2,3-propanetricarboxylic acid-co-hydrogen ethyl-exo-3,6-epoxy-l,2,3,6-tetrahydrophthalate) [poly(MTCA-co-HEET)], and poly(methacryloyl-2-oxy-l,2,3-propanetricarboxylic acid-co-a-ethoxy-exo-3,6-epoxy-1,2,3,6-tetrahydrophthaloyl-5-fluorouracil) [poly(MTCA-co-EETFU)] were synthesized and characterized. Their antitumor activity, inhibition of DNA replication and antiangiogenesis were examined. The structures of the polymers were identified by FT-IR, $^1H$ and $^{13}C$-NMR spectroscopy. The number average molecular weights of the fractionated polymers determined by GPC ranged from 9,400 to 14,900, and polydispersity indices were less than 1.7. The in vitro cytotoxicity of these polymers was determined and their antitumor activity was evaluated. The $IC_{50}$ values (the drug concentration at inhibition of 50% tumor growth) indicated that the synthesized polymers were much better inhibitors of cancer cells and showed lower cytotoxicity than the free 5-FU. The in vivo antitumor activity of the conjugates was examined using mice bearing the sarcoma 180 tumor cell line. The life spans (TIC) of the mice treated with the conjugates were higher than those treated with the free 5-FU. In addition, the synthesized conjugates showed excellent antiangiogenic activity based on an embryo chorioallantoic membrane assay.

• Fisheries and Aquatic Sciences
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• v.24 no.12
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• pp.406-414
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• 2021

The objective of this study was to investigate the yield and characteristics of collagen protein extracted from the muscle of four different species of mantis shrimp: Miyakella nepa, Harpiosquilla harpax, Erugosquilla woodmasoni, and Odontodactylus cultrifer. Mantis shrimp muscle was extracted by using a pepsin-solubilization technique, with 0.5 M acetic acid and 5% pepsin enzyme. The highest collagen yield was from M. nepa muscle (0.478 ± 0.06%), which was significantly greater (p < 0.05) than that from H. harpax, O. cultrifer, and E. woodmasoni (0.313 ± 0.03%, 0.123 ± 0.02%, and 0.015 ± 0.00%, respectively). The freeze-dried collagen appeared as thin fibers, and formed an opaque film. The pepsin-soluble collagen (PSC) from four mantis shrimp species was analyzed by gel electrophoresis. The results showed that all species of mantis shrimp contained type I collagen, consisting of β, α1, and α2 subunits with average molecular weights of 250, 145, and 118 kDa, respectively. The study of the solubility of collagen showed that, for NaCl, collagen had the highest relative solubility in 2% NaCl (80.20 ± 4.95%). In contrast, the solubility decreased at higher NaCl concentrations. However, in terms of pH, collagen had the highest relative solubility at pH 3 (91.32 ± 5.14%), and its solubility decreased at higher pH. FT-IR spectroscopy was used to compare the collagen with a model compound. Five wavenumbers in the spectrum for model collagen were identified: Amide A (3,406-3,421 cm^-1), amide B (2,916-2,940 cm^-1), amide I (1,639-1,640 cm^-1), amide II (1,539-1,570 cm^-1), and amide III (1,234-1,250 cm^-1).

• Microbiology and Biotechnology Letters
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• v.51 no.2
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• pp.157-166
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• 2023

Three lactic acid bacteria (LAB) producing exopolysaccharides (EPSs) were isolated from Pa (green onion)-kimchi, and identified as Weissella confusa (SKP 173), Weissella cibaria (SKP 182), and Leuconostoc citreum (SKP 281), respectively by 16S rRNA gene sequencing. The yields of EPS were 21.27, 18.53, and 15.4 g/l for EPS from SKP 173, 182, and 281, respectively when grown in MRS broth containing sucrose (5%, w/v). Total sugar contents were 64.39, 62.84, and 65.16% (w/w) for EPS from SKP 173, 182, and 281, respectively while the protein contents were 0.33, 0.31, and 0.25% (w/w), respectively. EPSs from W. confusa SKP 173 and W. cibaria SKP 182 contained glucose only but EPS from L. citreum SKP 281 contained glucose and glucitol. Viscosities of the 2% (w/w) freeze-dried EPS solution were 9.60, 8.00, and 8.20 centipoise (cP) for EPS from SKP 173, 182, and 281, respectively. Viscosities of culture grown in MRS broth with 5% sucrose (no glucose) were 92.98, 57.19, and 18.8 cP, respectively. The average molecular weights of EPSs were larger than 2 × 10⁷ Da. Fourier transform infrared spectroscopy (FT-IR) analyses of EPSs showed typical carbohydrate peaks, suggesting that the EPSs consisted of pyranose saccharides with α-(1,6) and α-(1,3) glycosidic linkages. L. citreim SKP 281 was used as the starter for yogurt fermentation, and EPS production was confirmed.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.223-229
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• 2010

In this study diverse dehydrogenative polymers (DHPs) were synthesized with three precursors of native lignin [p-coumaryl alcohol (PCA), coniferyl alcohol (CA), sinapyl alcohol (SA)] in the presence of horseradish peroxidase (HRP, EC. 1.11.1.7)/$H_2O_2$. To compare the structural features between DHPs and native lignin, the DHPs as well as pine/poplar milled wood lignins were simultaneously subjected to gel permeation chromatography (GPC) to determine average molecular weights and derivatization followed by reductive cleavage (DFRC) to investigate the frequency of ${\beta}$-O-4 linkage. The highest yield of DHP was measured to 71% when CA was solely injected (G-DHP) and the yield of H-DHP was 42%. However, single injection of SA could not form any polymer in this system. The average molecular weights of DHPs were ranged between 3,000~4,700, which were only 1/2 fold compared with that of pine MWL (G-type lignin: Mw 7,340) and 1/3 scale compared with that of poplar MWL (GS-type lignin: Mw 13,250). DFRC analysis revealed that the formation of ${\beta}$-O-4 linkage during dehydrogenative polymerization was the highest in the GS-DHP with ca. 502 ${\mu}mol$/g, which was, however, remained to only 50% compared to that in poplar MWL (1107 ${\mu}mol$/g). The ${\beta}$-O-4 linkage was estimated to ca. 286 ${\mu}mol$/g In the G-DHP, which was twice as much as that of H-DHP(127 ${\mu}mol$/g). Similar to GS-DHP, only half amount of ${\beta}$-O-4 linkage, compared to pine MWL, was formed during in vitro polymerization of CA by horseradish peroxidase/$H_2O_2$.

• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.74-80
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• 1994

As a preliminary study about the reduction of the antigenicity of whey protein isolate(WPI) by treatment of chymotrypsin, trypsin, pancreatin, and protease from Aspergillus oryzae, the properties and antigenicities of whey protein hydrolysates(WPH) were investigated. When degrees of hydrolysis (DH) were measured by use of trinitrobenzensulfonic acid(TNBS), the DH of the WPH treated by pancreatin or protease from Aspergillus oryzae$(5.05{\sim}11.47)$ were much higher than those of the tryptic or chymotryptic WPH$(15.67{\sim}20.20)$. And the pretreatments of heat$(75^{\circ}C)$, 20 min and/or pepsin resulted in higher DH of WPH, generally. When the molecular distributions of the WPH were determined by high performance size exclusion chromatography(HPSEC), the ratios of polypeptides with molecular weight more than 10kDa ranged from 12% to 36%, and the average molecular weights and the average peptide lengths of the WPH were $4,252{\sim}9,132$ dalton and $38{\sim}83$ amino acids, respectively. And there was no bitter taste in all of the WPH. Results of SDS-PAGE showed that most of intact native proteins were eliminated by the enzymatic hydrolysis but there were a few bands of peptides larger than 14.2 kDa in some WPH. When antigenicity was assayed by competitive inhibition enzyme-linked immunosorbent assay(cELISA), monovalent antigenicity of WPH to rabbit anti-WPI antiserum were lowered to $10^{-1.7}-10^{-4.9}$ times and less by the enzymatic hydrolysis. And the pretreatments of heat and pepsin resulted in the lowest antigenicicy within a group of enzymatic hydrolysis, especially in case of the pancreatic hydrolysate(PDP) whose antigenicity was found almost to be removed.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.121-127
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• 2010

In present work, sulfonated poly(arylene biphenyklsulfone ether) copolymers containing hydroquinone moiety were successfully synthesized using 4,4'-bis[(4-chlorophenyl)sulfonyl]-1,1'-biphenyl(BCPSBP), hydroquinone sulfonic acid potassium salt(sHQ), 4,4'-sulfonyldiphenol and evaluated their characteristics. Three kinds of polymer electrolyte membranes, PBPSEH-HQ00, PBPSEH-HQ10 and PBPSEH-HQ30 were prepared by using mole fraction of sulfonated hydroquinone(sHQ). The structure of the fabricated polymers was analyzed using NMR, IR and GPC. The Mw(weight-average molecular weights) of the polymers were in the range of 62,000-213,000 g $mol^{-1}$, and the molecular weight distribution (Mw/Mn) varied from 1.66-4.04. The thermal analysis of the copolymers was carried out by TGA and DSC. The temperature of Td5% and Td10% was decreased with the mole fraction of sHQ but Tg was increased with the mole fraction. The water uptake, IEC and ion conductivity were increased with increasing the ionic cluster of the polymers. The proton conductivity equal to 9.4 mS $cm^{-1}$ was measured for the PBPSEH-HQ30 membrane at $90^{\circ}C$ and 100% relative humidity. From the observed results it is clear that the prepared hydrocarbon membrane can be considered as suitable polymer electrolyte membrane for the application of PEMFC.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.66-72
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• 2016

In this study, a sulfonated poly(arylene ether ketone) block copolymer was prepared from hydrophilic oligomer and hydrophobic oligomer. The structure of the prepared membrane was characterized by $^1H$-NMR, FT-IR and GPC. The $M_w$(weight-average molecular weights) of the polymer was $209,700g\;mol^{-1}$ and the molecular weight distribution($M_w/M_n$) of 1.25 was obtained. The prepared membrane showed excellent thermal stability with gradual weight loss up to $200^{\circ}C$. The proton conductivity of SPAEK block copolymer reached the maximum of $9.0mS\;cm^{-1}$ at $90^{\circ}C$ under 100% relative humidity (RH). From the observed results, it is necessary to do more aggressive attempt to study the possibility of application as an ion-conductive composite electrolyte.

• Food Science and Preservation
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• v.15 no.4
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• pp.532-541
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• 2008

A central composite design was applied to investigate the effects of the independent variables of NaOH concentration(X1) and extraction time(X2) on dependent variables such as Yield(Y1), Xyl/Ara ratio(Y2), uronic acid(Y3), $\beta$-glucan(Y4) and total sugars(Y5) of hemicelluloses separated from rice bran. The Coefficients of determination(R2) in various models ranged from 0.8626 to 0.9319. Yield increased with increased NaOH concentration and extraction time. The optimum extraction conditions were NaOH concentration at 2.45M and extraction time of 24.2 h. Predicted values at the optimized conditions were acceptable, compared with experimental values. The structural characteristics of an optimum hemicellulose extract were explored. As a result, it showed that the surfaces of hemicellulose had a highly irregular reticulated structure. And also it was both small and large molecular particle in the hemicelluloses. Their average molecular weights were in the ranges $235{\sim}240$ kDa and $8.0{\sim}9.4kDa$, respectively.

• Journal of Animal Science and Technology
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• v.50 no.5
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• pp.621-632
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• 2008

Genetic polymorphisms was investigated at five single nucleotide polymorphisms(SNP) sites in four porcine genes(ADCYAP1R1, FABP3, MC4R, and MYL2) and analyzed their statistical association with growth traits in F2 reciprocal-crossbred population between Landrace and Jeju native black pig(JNP). All populations, JNP, Landrace and their F2 were polymorphic for all five SNP loci tested, however, the homozygote T/T of FABP3 g.-158T>C and the homozygote G/G of ADCYAP1R1 intron 2 337A>G were not found in JNP and Landrace, respectively. The genotypes of ADCYAP1R1 were significantly associated with body weights(BW) at 3 weeks and at 20 weeks(P<0.05), respectivley, those of FABP3 g.-135delT were associated with late average daily gain(LADG) (P<0.01), and those of FABP3 g.-158T>G were associated with body weights during late growth period such as, BW20 and LADG(P<0.01). Those of MC4R were also significantly associated with BW10 suggesting by the difference of early average daily gain(EADG) (P<0.05), and with LADG(P<0.01). The body length of F2 animals was affected by the genotypes of ADCYAP1R1, MC4R, and MYL2(P<0.05), respectively. Among these, MC4R A/A homozygotes showed over 3 cm longer in body length than those of other genotypes. As the useful basic information, these results suggested that SNP markers showing statistical association with growth traits and the results help to select the sires of JNP for improving the productivity in JNP-related crossbreeding system in pig industry and also to construct the molecular breeding system for breed improvement of JNP itself.