• Biomaterials and Biomechanics in Bioengineering
• /
• v.3 no.1
• /
• pp.37-46
• /
• 2016

To maintain activity in a coenzyme/enzyme mixture system, such as ${\beta}$-nicotinamide adenine dinucleotide (NADH)/dehydrogenase, the water-soluble 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers as an additive were synthesized and investigated for their stabilizing function. The inhibitor for the NADH/dehydrogenase reaction was spontaneously formed when the NADH was stored in the dehydrogenase solution. Therefore, we hypothesized that if the additive polymer could interact with an inhibitor without any adverse effect on the dehydrogenase, the activity in the NADH/dehydrogenase mixture could be maintained. We selected lactose dehydrogenase (LDH) as the enzyme, and the NADH was dissolved and incubated at $37^{\circ}C$ in the LDH solution containing the polymers. The phospholipid polymers used in this study were poly(MPC) (PMPC), poly(MPC-co-3-trimethylammonium-2-hydroxypropyl methacrylate chloride) (PMQ) and poly[MPC-co-potassium 3-methacryloyloxypropyl sulfonate ($MSO_3$)] ($PMMSO_3$). The poly($MSO_3$) was used as a reference. For the PMQ and $PMSO_3$ aqueous solutions, the activity of the NADH/LDH mixture system decreased with incubation time as the same level or lower than that in the Tris buffered solution in the absence of the polymers. However, for the poly($MPC-co-MSO_3$) ($PMMSO_3$) aqueous solution, the activity of the NADH/LDH mixed system was six times higher than that in the buffered solution even after a 3-days incubation. The LDH activity was 1.5-1.8 times higher in the presence of the $PMMSO_3$ compared with that in the $PMSO_3$ solution. The mixture of two polymers, poly(MPC) and poly($MSO_3$), did not produce any stabilization. Thus, both the MPC and $MSO_3$ units in the polymer chain had important and cooperative effects for stabilizing the NADH/LDH mixture.

• Macromolecular Research
• /
• v.12 no.1
• /
• pp.46-52
• /
• 2004

In a continuation of our previous studies on blood compatibility profiles of anion-substituted poly(vinyl alcohol) (PVA) membranes, in which hydroxyl groups have been replaced with carboxymethyl (C-PVA) and sulfonyl groups (S-PVA), we have studied the activation of complement components and the changes in white cell and platelet count in vitro and compared them with those of unmodified PVA, Cuprophane, and low-density polyethylene. Complement activation of fluid phase components, C3a, Bb, iC3b, and SC5b-9, and of bound phases, C3c, C3d, and SC5b-9, were assessed by enzyme-linked immunosorbent assay (ELISA) and immunoblot, respectively. The changes in the number of white cells and platelets following complement activation were counted using a Coulter counter. C-PVA and S-PVA activated C3 to a lesser extent than did PVA, which we attribute to the diminished level of surface nucleophiles of the samples. In addition, C- and S-PVA exhibit increased inhibition of Bb production, resulting in a decrease in the extent of C5 activation. Consequently, because of the reduced activation of C3 and C5, C- and S-PVA samples cause marked decreases in the SC5b-9 levels in plasma. We also found that the negatively charged sulfonate and carboxylate groups of the samples cause a greater extent of adsorbtion of the positively charged anaphylatoxins, C3a and C5a, because of strong electrostatic attraction, which in turn provides an inhibition of chemotaxis and activation of leukocytes. The ability to inhibit complement production, together with the binding ability of anaphylatoxins of the C- and S-PVA samples, leads to a prominent decrease in lysis of leukocytes as well as activation of platelets.

• Journal of Adhesion and Interface
• /
• v.11 no.3
• /
• pp.112-119
• /
• 2010

Poly(methyl methacrylate)/poly(butyl acrylate) PMMA/PBA core-shell composite particles were prepared by the emulsion polymerization of MMA and BA in the presence of different concentration of sodium dodecyl benzene sulfonate (SDBS). The following conclusions are drawn from the measured conversion and particle size distribution, morphology, average molecular weight distribution, observation of film formation and particle formation, glass transition temperature and physical properties of polymerized core-shell composition particles for using adhesive binder. When the concentration of 0.03 wt% surfactant, the conversions of PMMA and PBA core polymerization are excellent as 95.8% for PMMA core and 92.3% for PBA core. Core-shell composite particles are obtained 90.0% for PMMA/PBA core-shell composite particles and 89.0% for PMMA/PBA core-shell composite particles. It is considered that the core and shell particles are polymerized to be confirmed FT-IR spectra and average molecular weight measured with a GPC, formation of the composite particles is confirmed by the film formation from normal temperature, and composition of inside and outside of the composite particle is confirmed by TEM photograph. The synthesized polymer has two glass transition temperatures, suggesting that the polymer is composed of core polymer and shell polymer unlike general copolymers. It is considered that each core-shell composite particle can be used as a high functionality adhesion binder by the measurement of tensile strength and elongation.

• Elastomers and Composites
• /
• v.45 no.1
• /
• pp.40-43
• /
• 2010

In this study, polyimide(PI) nanofibers mats were prepared by electrospinning and three different fiber morphologies of random, uniaxial, and biaxial orientation were prepared by controlling the speed of drum-shaped collector and other parameters. The SEM studies reveal that the aforesaid morphologies were obtained on the nano-fibrous mats prepared. The ionic conductivity was measured using an in-plane type conductivity tester for the PI mats soaked in the mixture of 1M lithium trifluoro-methane-sulfonate and tetra-ethylene glycol dimethyl ether. The ionic conductivity was surprisingly higher for the biaxial PI mats. For the uniaxially-oriented mats, the ionic conductivity was found to be higher in the parallel direction compared to the perpendicular direction of the fiber orientation. A curious cyclic fluctuation was found in the ionic conductivity with time. The observed behavior was explained by considering the distance between fibers and transport speed of ions used in this study.

• Korean Journal of Food Science and Technology
• /
• v.20 no.2
• /
• pp.164-169
• /
• 1988

Protoplast susion between Zygosaccharmoyces rouxii M-12 and Saccharimyces cerevusuare M-43 were investigated for breeding of a new brewing yeat strain for soy sauce. Auxotrophic mutants of Zygosaccharomyces rouxii ZRM-83 ($Met^-,\;Thr^-$) and Saccharomyces cerevisiae SCM-46 ($Lys^-,\;Arg^-$) were selected by treatment of 3.0% ethylmethane sulfonate and nutritional complementary method. Protoplast of both strains were more effective by treatment of 0.05mg/ml zymolase 20T for 60min. Fusion effeciency was much higher by treatment of 30% PEG 6,000 for 30min and fusion frequencies were $10^{-4}{\sim}10^{-5}$. These fusants originated from two protoplasts had properties of big cell size and much DNA content.

• The Korean Journal of Physiology
• /
• v.30 no.1
• /
• pp.53-62
• /
• 1996

Transepithelial transport of tetraethylammonium (TEA) was studied in monolayers of opossum kidney cells cultured on permeable membrane filters. $[^{14}C]-TEA$ was transported across the OK cell monolayer from basolateral to apical side by a saturable process which can be stimulated by acidification of the apical medium. The apparent Michaelis-Menten constant $(K_{m})$ and the maximum velocity$(V_{max})$ for the transport were $41\;{\mu}M$ and 147 pmole/ mg protein/ min, respectively. The transport was significantly inhibited by unlabelled TEA, amiloride, cimetidine, choline, and mepiperphenidol added to the basolateral side at 1 mM and was slightly inhibited by 5 mM $N_{1}-methylnicotinamide\;(NMN).$ Unlabelled TEA added to the apical side stimulated the $basolateral-to-apical\;{^{14}C}-TEA$ transport, suggesting that the TEA self-exchange mechanism was involved at the apical membrane. Sulfhydryl reagents such as ${\rho}-chloromercuribenzoic\;acid\;(PCMB)\;and \;{\rho}-chloro-mercuribenzene\;sulfonate \;(PCMBS)$ and carboxyl reagents such as N,N'-dicyclohexylcarbodiimidem (DCCD) and N-ethoxy-carbonyl-2-ethoxy-1,2-dihydro-quinoline(EEDQ) inhibited the TEA transport at both the basolateral and apical membranes of the OK cell monolayer. These results suggest that OK cell monolayers possess a vectorial transport system for organic cations which is similar to that for organic cation secretion in the renal proximal tubule.

• Korean Journal of Microbiology
• /
• v.25 no.1
• /
• pp.57-66
• /
• 1987

Mutants of E. coli which showed increased sensitivity to MMS(methylmethane sulfonate)were isolated by MNNG mutagenesis and characterized by enzymatic assay, survival of simple alkylating agents and host-cell reactivation. E.coli mutant, 5-62, which showed absolute deficiency in 3-methyladenine DNA glycosylase II activity and had low capability of reactivating MMS-treated phage charon 35 was very sensitive to MMS and MNNG. NNS gene which confered resistance to the lethal effects of MMS was cloned in 5-62 strain. 5-62 mutants carrying recombinant plasmid, pMRG 1, which acquired resistance to the lethal effects of MMS had normal sensitivity to MNNG. Resistance to MMS was somewhat increased after they were treated with 0.5.$\mu$g MNNG/ml for 2 hours at $37^{\circ}C$. Although recombinant plasmid, pMRG 1, did not complement alk A mutation in 5-62 and ada mutation in 1-27 mutnat, mutnats transformed with this plasmid showed more capability of reactivating MMS treated phage than mutants.

• Journal of Life Science
• /
• v.16 no.1
• /
• pp.126-130
• /
• 2006

The present study intends to characterize the DNA damage-inducible responses in yeast. The fission yeast, Schizosaccharomyces pombe was used in this study as a model system for higher eukaryotes. To study UV-inducible responses in S. pombe, five UV-inducible cDNA clones were isolated from S. pombe by using subtration hybridization method. To investigate the expression of isolated genes, UVI-155, the cellular levels of the transcripts were determined by Northern blot analysis after UV-irradiation. The transcripts of isolated gene (UVI-155) increased rapidly and reached maximum accumulation after UV-irradiation. Compared to the message levels of control, the levels of maximal increase were approximately 5 fold to UV-irradiation. In order to investigation whether the increase of UVI-l55 trascripts was a specific results of UV-irradiation, UVI-155 transcript levels were examined after treating the cells to mthylmethane sulfonate (MMS). The transcripts of UVI-155 were not induced by treatment of $0.25\%$ MMS. These results implied that the effects of damaging agents are complex and different regulatory pathways exist for the induction of these genes. To characterize the UVI-155 gene, gene deletion experiments were analyzed. The deleted strain was not well grown. This result indicated that the UVI-155 gene is essential for cell viability.

• Environmental Analysis Health and Toxicology
• /
• v.25 no.3
• /
• pp.229-240
• /
• 2010

During the last decade, perfluorinated compounds (PFCs) have gained more attention due to their toxicity and global distribution. The aim of this study was to examine the distribution and bioaccumulation of perfluorinated compounds (PFCs) in aquatic wildlife effected from a sewage treatment plant. The concentrations of 12 PFCs were determined in water, sediment and fish samples. PFOS were predominantly detected in both ambient environment and fish. In fish, the concentration of PFCs in blood was the highest (i.e., 112.47 ng/mL wet-wt. PFOS) in comparison to other tissues. However, PFOA and PFHpS were highly detected in gonad as 3.87 and 4.58 ng/g wet-wt., respectively. The bioconcentration factor (BCF) of PFCs was greatest in the blood > liver${\cong}$gonad > kidney > gill, and lowest in the muscle tissue. The BCFs of PFUnDA (39,000), PFDA (2,700) and PFOS (1,100) were rated as high values based on wet weight concentration. BCFs increased with increasing the length of the perfluoralkyl chain.

• Korean Journal of Materials Research
• /
• v.3 no.3
• /
• pp.237-244
• /
• 1993

The characteristics of composite polymer electrolytes obtained by adding a fine ceramic powder($\gamma-{LiAlO}_{2}$) with a diameter of $1{\mu}$m to a poly(ethylene oxide)/lithium trifluoromethane sulfonate (LiC$F_3$S$O_3$) complex are described in terms of morphological and mechanical behavior. The addition of uniformly dispersed ceramic powder greatly improves the electrical and mechanical properties of solid polymer electrolytes at ambient temperature. For the composite polymer electrolytes under this study, the optimum composition of the $\gamma-{LiAIO}_{2}$ in the composite for maximum ionic conductivity was found to be 20 wt%.