• Journal of Life Science
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• v.18 no.11
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• pp.1617-1624
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• 2008

Chitin and chitosan, which is deacetylated form of chitin, are one of the most abundant biomass on the earth. They showed various biological activities including antimicrobial activity, heavy metal chelating, immune system activation, and have very diverse applications in food, pharmaceutical, medicinal, and environmental industry. There have been reported many chitin/chitosan-hydrolyzing enzymes, their structures and genes from three domains, archaea, bacteria, and eukarya. Carbohydrate hydrolyzing enzymes are classified in CAZy (Carbohydrate Active Enzymes) database according to their amino acid sequence similarity. Interestingly, chitinases and chitosanases are classified in various glycosyl hydrolase(GH) families, GH2, GH5, GH7, GH8, GH18, GH19, GH20, GH46, GH48, GH73, GH75, GH80, GH84, and GH85. Here, we review characteristics and structures of chitin/chitosan hydrolyzing enzymes according to glycosyl hydrolase families in order to provide information about gene mining.

• Journal of Life Science
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• v.31 no.3
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• pp.356-365
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• 2021

Recently, we sequenced the entire genome of a freshwater agar-degrading bacterium Cellvibrio sp. KY-GH-1 (KCTC13629BP) to explore genetic information encoding agarases that hydrolyze agarose into monomers 3,6-anhydro-L-galactose (L-AHG) and D-galactose. The KY-GH-1 strain appeared to possess nine β-agarase genes and two α-neoagarobiose hydrolase (α-NABH) genes in a 77-kb agarase gene cluster. Based on these genetic information, the KY-GH-1 strain-caused agarose degradation into L-AHG and D-galactose was predicted to be initiated by both endolytic GH16 and GH86 β-agarases to generate NAOS (NA4/NA6/NA8), and further processed by exolytic GH50 β-agarases to generate NA2, and then terminated by GH117 α-NABHs which degrade NA2 into L-AHG and D-galactose. More recently, by employing E. coli expression system with pET-30a vector we obtained three recombinant His-tagged GH50 family β-agarases (GH50A, GH50B, and GH50C) derived from Cellvibrio sp. KY-GH-1 to compare their enzymatic properties. GH50A β-agarase turned out to have the highest exolytic β-agarase activity among the three GH50 isozymes, catalyzing efficient NA2 production from the substrate (agarose, NAOS or AOS). Additionally, we determined that GH117A α-NABH, but not GH117B α-NABH, could potently degrade NA2 into L-AHG and D-galactose. Sequentially, we examined the enzymatic characteristics of GH50A β-agarase and GH117A α-NABH, and assessed their efficiency for NA2 production from agarose and for production of L-AHG and D-galactose from NA2, respectively. In this review, we describe the benefits of recombinant GH50A β-agarase and GH117A α-NABH originated from Cellvibrio sp. KY-GH-1, which may be useful for the enzymatic hydrolysis of agarose for mass production of L-AHG and D-galactose.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1188-1192
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• 2003

Negative feedback on GH responses to GH-releasing hormone (GHRH) and GH-releasing peptides (GHRPs) has been reported and this action has been suggested to act through an increase in somatostatin. To determine whether the acute administration of porcine GH (pGH) inhibits GH responsiveness to GHRP-2 and GHRH in swine, swine were intravenously administered with pGH (5${\mu}g$/kg BW) or placebo followed 180 min later by a second intravenous administration of saline, GHRP-2 (30 ${\mu}g$/kg BW), GHRH (1${\mu}g$/kg BW) and a combination of GHRP-2 and GHRH. Plasma GH concentration was measured by radioimmunoassay. Administration of pGH caused a significant increase in GH area under curve and GH peak concentrations (p<0.001) over placebo-treated group. Plasma GH concentrations peaked at 15 min and returned to baseline level within 90 min. Pretreatment of pGH abolished (p<0.01) GH response to GHRH and attenuated (p<0.05) GH response to GHRP-2 and GHRH combined, without affecting GH response to GHRP-2. These results demonstrate that negative feedback action on GH releasing effect of GHRH occurs in swine, and that GHRP-2 has ability to interact in this action.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.127-136
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• 1998

A chimeric gene comprising murine whey acidic protein(mWAP) and human growth hormone(hGH) was used to produce transgenic rats express hGH and secrete it into the blood. Two lines of transgenic rats carrying the mWAP/hGH construct were established; High line was characterized by relatively high levels of serum hGH, and low line had relatively low levels. The secretory profiles of rat GH(rGH) as well as hGH, the transgene product, were obtained in transgenic males and females of low line; both hGH and rGH serum levels were flattened with no episodic fluctuations, and the overall mean concentration of rGH was significantly lower than in normal littermates. Although the animals of High line showed an acceles, as assessed by vaginal opening and occurrence of first ovulation, advanced by 7∼8 days in both lines of animals. Accordingly, the body weight at puberty of low line transgenic females was much lower than that of normal littermates, indicating that continuous hGH expression could induce precocious puberty without enhancing the growth rate.

• Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.43-47
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• 2012

Growth hormone (GH) transgenesis in fish has the potential to improve aquaculture efficiency and capacity. However, many fast-growing transgenic fish have experienced side effects caused by excess GH expression. To overcome this unwanted issue associated with several GH transgenic mud loach Misgurnus mizolepis lines carrying GH construct driven by a strong ${\beta}$-actin regulator ($pml{\beta}$-actGH), we performed an alternative version of GH autotransgenesis using a weaker but more stable regulator, the mud loach lectin promoter. GH transgenesis with a pmlectGH construct consisting of the mud loach GH gene driven by the 2.3-kb lectin promoter exhibited significant growth stimulation. However, the extent of the growth acceleration in pmlectGH transgenics (six times maximum when assessed 2 months post hatching) was much less than that in transgenic individuals carrying the $pml{\beta}$-actGH construct. Additionally, the extraordinary gigantism that was common in $pml{\beta}$-actGH-transgenic mud loaches was diminished in transgenic loaches harboring the pmlectGH construct. Transgenic founders (pmlectGH) successfully transmitted their transgene into the next generation with up to 41% frequency. Growth stimulation also persisted in the transgenic F1 strains, with a seven-fold increase in maximum body weight at 6 months of age.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.947-954
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• 2009

Starting from the Eu's GH(Generalized Hydrodynamic) theory, the multi-species GH numerical solver is developed in this research and its computatyional behaviors are examined for the hypersonic rarefied flow over an axisymmetric body. To improve the accuracy of the developed multi-species GH solver, various slip-wall boundary conditions are tested and the computed results are compared. Additionally, in order to validate the entropy characteristics of the GH equation, the entropy production and entropy generation rates of the GH equation are investigated in the 1-dimensional normal shock structure test at a high Knudsen number.

• KSBB Journal
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• v.10 no.3
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• pp.271-282
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• 1995

The authentic hGH converted from met-hGH by immobilized ApM was purified by successive chromatographic processes based on the differences in isoelectric points, hydrophobicities and charges. The final recovery yield was about 14.1% and the specific activity of the purified hGH was 2.75IU per mg when assayed by enzyme immunoassay. The purified hGH was verified to be authentic hGH through the analysis of amino acid composition, amino-terminal amino acid sequence, carboxy-terminal amino acid and tryptic peptide map. The purity of purified hGH was higher than that of commercial hGH when assessed by SDS-PAGE, PAGE, IEF and HSGF. In weight-gain assay and tibia test with hypophysectomized rats, the hGH produced in this study showed the same growth effect as the commercial hGH.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.84-91
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• 2008

Generalized hydrodynamic (GH) theory for multi-species gas and the computational models are developed for the numerical simulation of hypersonic rarefied gas flow on the basis of Eu's GH theory. The rotational non-equilibrium effect of diatomic molecules is taken into account by introducing excess normal stress associated with the bulk viscosity. The numerical model for the diatomic GH theory is developed and tested. Moreover, with the experience of developing the dia-tomic GH computational model, the GH theory is extended to a multi-species gas including 5 species; O$_2$, N$_2$, NO, O, N. The multi-species GH model includes diffusion relation due to the molecular collision and thermal phenomena. Two kinds of GH models are developed for an axisymmetric flow solver. By compar-ing the computed results of diatomic and multi-species GH theories with those of the Navier-Stokes equations and the DSMC results, the accuracy and physical consistency of the GH computational models are examined.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.84-91
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• 2008

Generalized hydrodynamic (GH) theory for multi-species gas and the computational models are developed for the numerical simulation of hypersonic rarefied gas flow on the basis of Eu's GH theory. The rotational non-equilibrium effect of diatomic molecules is taken into account by introducing excess normal stress associated with the bulk viscosity. The numerical model for the diatomic GH theory is developed and tested. Moreover, with the experience of developing the dia-tomic GH computational model, the GH theory is extended to a multi-species gas including 5 species; $O_2,\;N_2$, NO, O, N. The multi-species GH model includes diffusion relation due to the molecular collision and thermal phenomena. Two kinds of GH models are developed for an axisymmetric flow solver. By compar-ing the computed results of diatomic and multi-species GH theories with those of the Navier-Stokes equations and the DSMC results, the accuracy and physical consistency of the GH computational models are examined.

• Biomolecules & Therapeutics
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• v.10 no.3
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• pp.175-179
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• 2002

Human growth hormone (hGH) forms antibody by repeated administration. The present study investigated to confirm formation of antibody by repeated subcutaneous administration of hGH for two months in rats and dogs. In this result, hGH-injected sera were significantly higher than control sera by 1:1,000,000 of dilution factor. After antibody formed sera (anti-hGH sera) and control sera were added to 30 $\mu\textrm{g}$/ml hGR, the complex incubated for overnight at $30^{\circ}C$. Anti-hGH sera decreased hGH contents about 90% compared to control sera. Also, body weight gain conducted decreased about 67% compared to control sera in hypophysectomised rat. Inconclusion, repeated administration of hGH formed antibody because hGH was foreign protein to rats and dogs. And formed antibody of hGH was blocked and decreased many efficacy of hGH, the antibody was proved to be neutralizing antibody. Thus, because neutralizing antibodies were decreased pharmacological effects of hGH, administration more than two months were no significance.