• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.571-578
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• 2018

Biofuel production using lignocellulosic biomass is gaining attention because it can be substituted for fossil fuels without competing with edible resources. However, because Saccharomyces cerevisiae does not have a ${\text\tiny{D}}$-xylose metabolic pathway, oxidoreductase or isomerase pathways must be introduced to utilize ${\text\tiny{D}}$-xylose from lignocellulosic biomass in S. cerevisiae. To elucidate the biochemical properties of xylose isomerase (XI) from Piromyces sp. E2 (PsXI), we determine its crystal structure in complex with substrate mimic glycerol. An amino-acid sequence comparison with other reported XIs and relative activity measurements using five kinds of divalent metal ions confirmed that PsXI belongs to class II XIs. Moreover kinetic analysis of PsXI was also performed using $Mn^{2+}$, the preferred divalent metal ion for PsXI. In addition, the substrate-binding mode of PsXI could be predicted with the substrate mimic glycerol bound to the active site. These studies may provide structural information to enhance ${\text\tiny{D}}$-xylose utilization for biofuel production.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.516-521
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• 2014

A bacterium producing ${\alpha}$-galactosidase (${\alpha}$-$\small{D}$-galactoside galactohydrolase, EC 3.2.1.22) was isolated. The isolate, KM-1 was identified as Bacillus coagulans based on its 16S rRNA sequence, morphology, and biochemical properties. ${\alpha}$-Galactosidase activity was detected the culture supernatant of B. coagulans KM-1. The bacterium showed the maximum activity for hydrolyzing para-nitrophenyl-${\alpha}$-$\small{D}$-galactopyranoside (pNP-${\alpha}Gal$) at pH 6.0 and $50^{\circ}C$. It hydrolyzed oligomeric substrates such as melibiose, raffinose, and stachyose liberating a galactose residue, indicating that the B. coagulans KM-1 ${\alpha}$-galactosidase hydrolyzed ${\alpha}$-1,6 linkage. The results suggest that the decreased stachyose and raffinose contents in fermented soybean meal are due to the ${\alpha}$-galactosidase activity.

• Advances in Traditional Medicine
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• v.8 no.4
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• pp.386-394
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• 2008

The tissue extract (TTE) of a marine snail Telescopium telescopium, collected from the coastal regions of West Bengal, India, was extensively screened for pharmacological and biochemical properties. Telescopium telescopium (TTE) produced significant lysis of washed rat erythrocytes (both direct and indirect), produced haemorrhagic lesions in the skin and also released haemoglobin (in vitro tissue damage) from different tissue samples. TTE was found to produce pro-inflammatory effects when injected into the rat hind paw and also increased peritoneal vascular permeability. Furthermore, intravenous administration of TTE produced a decrease in blood pressure (hypotensive effect) in anaesthetized rats. The extract produced potent esterase activity, as was evident from the breakdown of FDA with subsequent release of fluorescein (in vitro). TTE also demonstrated prominent cholinesterase, phospholipase, phosphatase and protease activities.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.335-339
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• 2014

The studies on the characteristics of composite of silica aerogel and pulps were carried out. The composite was manufactured by mixing the paste of silica aerogel and pulps and analyzed by SEM. Using the impedence tube, the sound absorption measurement was investigated. The maximum value of sound absorption coefficient of this composite was obtained in the range of 900 Hz. It was found that the composite of silica aerogel and pulps could be a new sound absorbent because of high absorption capacity and durability which was due to hydrophobic effect on the surface of the composite.

• Journal of Mechanical Science and Technology
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• v.17 no.2
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• pp.296-309
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• 2003

The periodicity of the physiological flow has been the major interest of analytic research in this field up to now Among the mechanical forces stimulating the biochemical reaction of endothelial cells on the wall, the wall shear stresses show the strongest effect to the biochemical product. The objective of present study is to find the effects of velocity waveform on the wall shear stresses and pressure distribution along the artery and to present some correlation of the velocity waveform with the clinical observations. In order to investigate the complex flow phenomena in the bifurcated tube, constitutive equations, which are suitable to describe the rheological properties of the non-Newtonian fluids, are determined, and pulsatile momemtum equations are solved by the finite volume prediction. The results show that pressure and wall shear stresses are related to the velocity waveform of the physiological flow and the blood viscosity. And the variational tendency of the wall shear stresses along the flow direction is very similar to the applied sinusoidal and physiological velocity waveforms, but the stress values are quite different depending on the local region. Under the sinusoidal velocity waveform, a Newtonian fluid and blood show big differences in velocity. pressure, and wall shear stress as a function of time, but the differences under the physiological velocity waveform are negligibly small.

• Elastomers and Composites
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• v.52 no.2
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• pp.143-153
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• 2017

Herein we studied the characterization of the PBO films formed via solution casting and thermal cyclization of poly(o-hyroxyamide)s(PHAs) that were synthesized by direct polycondensation of 3,3'-dihydroxybenzidine with 4,4'-(2,3-quinoxalinedioxy) dibenzoic acid and/or 4,4'-(2,3-pyridinedioxy) dibenzoic acid. All the PHAs exhibited inherent viscosities in the range of 0.55~0.84 dL/g in DMAc solution. The copolymers, CPH-2-5, were partially soluble in less polar solvents like pyridine and THF. However, all the PBOs were not soluble in polar solvents, but only partially soluble in sulfuric acid. The temperatures corresponding to 10% weight loss of the PBOs with increasing content of quinoxalinedioxy unit were higher than those of the PHAs, and the char yields at $900^{\circ}C$ in $N_2$, tensile strength, and initial modulus of the PBOs were 1.1~1.3 times, 1.2~1.8, and 1.6~3.3 times higher, respectively, than those of the PHAs. The LOI value of CPB-2 was 38.5%, while that of CPB-1 was the highest at 40.0%. The LOI test confirmed that excellent flame retardants were synthesized.

• Korean Journal of Veterinary Research
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• v.35 no.2
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• pp.297-306
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• 1995

The present study was conducted to investigate the incidence of Streptococcus suis infection in the pneumonic lungs of slaughter pigs from December 1992 to April 1994 and to examine the biochemical and cultural properties, the antimicrobial susceptibility and serotype of the isolates. Fifty-six(7.95%) strains of S suis was isolated from 704 pneumonic lungs of slaughter pigs, of which 33 cultures were isolated alone, while remaining 18 were complicated wide Pasteurella multocida. Of the 56 S suis isolates, 18(32.1%) were serotype 2, 5(8.9%) were serotype 1/2, 2 were serotype 1, 1 each for serotype 3 & 5, and the remaining 29 were untypable. The twenty five strains(44.6%) of all isolates produced hyaluronidase while 15 strains(88.3%) of 18 serotype 2 isolates were hyaluronidase producers. All of isolates were highly susceptible to ampicillin, amoxicillin, ceftiofur, cephalothin, ciprofloxacin and penicillin G, although the majority of them were resistant to kanamycin, colistin, erythromycin, oxytetracycline.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.5
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• pp.484-489
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• 2011

This study examined whether N-acetylcysteine (NAC), a glutathione precursor, could attenuate toxic effects of three fish anti-parasitic agents, trichlorfon, hydrogen peroxide ($H_2O_2$) and formalin, all of which are known to exert side effects through free radical production. Common carp Cyprinus carpio were fed with NAC (approx. 50 mg/kg/day) for 3 consecutive days prior to anti-parasite bathing for a 24 hr period. Mortality rates were examined during this 24 hr bathing period, and selected hematological and biochemical parameters were also assessed at the termination of anti-parasite exposure. The mortality rates and plasma glucose elevations caused by all three anti-parasitics were significantly reduced by NAC pretreatment. Trichlorfon, but not $H_2O_2$ or formalin, elevated plasma levels of aspartatetransaminase (AST) and alanine-transaminase (ALT), and these elevations were attenuated by NAC. There was no change in hematocrit values in any treatment. The results provide evidence for the attenuating effects of NAC against toxicity caused by anti-parasite agents that act through free radical-producing properties. The results found in this study also suggest that NAC may be administered to fish to minimize toxicity in fish parasiticide use.

• Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.54-59
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• 2009

Carotenoids such as $\beta$-carotene and astaxanthin are used as food colorants, animal feed supplements and for nutritional and cosmetic purposes. In a previous study, an astaxanthin biosynthesis gene cluster was isolated from the marine bacterium, Paracoccus haeundaensis. Geranylgeranyl pyrophosphate (GGPP) synthase (CrtE), encoded by the ortE gene, catalyzes the formation of GGPP from farnesyl pyrophosphate (FPP), which is an essential enzyme for the biosynthesis of carotenoids in early steps. In order to study the biochemical and enzymatic characteristics of this important enzyme, a large quantity of purified GGPP synthase is required. To overproduce GGPP synthase, the crtE gene was subcloned into a pET-44a(+) expression vector and transformed into the Escherichia coli BL21(DE3) codon plus cell. Transformants harboring the crtE gene were cultured and the crtE gene was over-expressed. The expressed protein was purified to homogeneity by affinity chromatography and applied to study its biochemical properties and molecular characteristics.

• Elastomers and Composites
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• v.50 no.2
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• pp.138-145
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• 2015

A series of wholly aromatic poly(hydroxyamide)s(PHAs), containing varying amounts of 2,6-dimethylphenoxy group and quinoxaline ring in the main chain, were synthesized by a direct polycondensation method. The inherent viscosities of the PHAs in either DMAc or DMAc/LiCl solution at $35^{\circ}C$ were found to be in the range of 1.02~1.90 dL/g. In the solubility study, we observed that PHA 1, PHA 2, and PHA 3 were dissolved in aprotic solvents such as DMAc, NMP, DMF, and DMSO with LiCl on heating; however, PHA 4, PHA 5, and PHA 6 could be dissolved in aprotic solvents on heating without LiCl. For poly(benzoxazole)s(PBOs), the 10% and maximum weight loss temperatures were in the range of $582{\sim}622^{\circ}C$ and $630{\sim}659^{\circ}C$, respectively. Residues of PBOs at $900^{\circ}C$ were found to be relatively high, which were in the range of 65.3~70.8%.