• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.381-388
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• 2001

The present study was designed to obtain porcine growth hormone binding protein (pGHBP) improved biological activation as derived mutation in binding site with growth horlnone (GH). A 756 bp of fragment encoding the extracellular domain of pGHBP gene was cloned from the total RNA of porcine fat tissue by reverse transcriptase polymerase chain reaction (RT-PCR) and created mutation in positions 26 and 122 using site-directed mutagenesis method. Position 26 is one and it is near to get on five potential N-linked glycosylation sites located in the extracellular domain of porcine growth hormone receptor known to have a direct influence on combination with GH. Position 122 is known as one of conformational epitope in bovine. It was over-expressed in E. coli using pET-32(c) expression vector and precisely purified by S-protein agarose and enterokinase. In our results, we was obtained pmGHBP of 30 kDa. It suggests to study the effects of the pmGHBP on cell proliferation in vitro and growth rate in vivo after administration.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.231-234
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• 2011

This study was performed to develop new Hypsizygus marmoreus cultivars that have enhanced functional materials and improved physiological characteristics with mutagenesis by gamma ray irradiation. Protoplasts of H. marmoreus brown strain HYM-056 were irradiated by gamma ray for mutagenesis, and then 2,000 clones of mutants were randomly selected and the fruiting bodies were induced by bottle culture. Among them, 157 isolates with fast-growing, heavy and many fruiting body-producing were selected. The isolates were cultured in plastic bottle containing rice bran, barley hulls and fir sawdust to form the fruiting bodies. About 100 days after inoculation, characteristic of fruiting bodies were investigated. The isolates were divided into 6 groups based on color, shape and size of pileus, and length, diameter, number and weight of stipe. In addition, the genetic variation of the isolates was analyzed by URP-PCR fingerprinting.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.222-227
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• 1991

Rhizobium fredii USDA193 is one of the causal organism for root nodule formation in soybean (peking). Previously we cloned the pectate lyase gene (SY1) of R. fredii USDA193. The $pel^-$ mutants (SY1$\Omega$ and SY1$\Omega$1) of SY1 were obtained using the in vitro insertional omega mutagenesis of RpelB (of Rhizobium pel) and fill-in reaction of RpelE (of Rhizobium pel) gene respectively, and we constructed two mutants (R, fredii USDA193$\Omega$ and R. fredii USDA193$\Omega$1) in pectate lyase function by marker-exchange with pe1B::$\Omega$ and R. fredii USDA193 strain (rif). The pectate lyase activity of two pel- mutant of R. fredii USDA193 was determined by spectrophotometric method. However, all pectate lyase activity of these mutants was not lost upon the mutagenesis by marker-exchange. This suggests that other pectate lyase genes may be present on the plasmid or the chromosome of R. fredii. As yet we do not have evidence linking RpelB and RpelE genes of R. fredii directly to the early nodulation process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.745-750
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• 1998

The antimutagenic and antigenotoxic effects of ethanol, methanol, water and non-heating ethanol extract of Ligularia fischeri were investigated using Ames test and micronucleus test. Four solvent extracts by themseleves did not induce mutagenesis. The four extract of 200㎍/plate showed approximately 84.7%, 77.1%, 72.5% and 71% inhibitory effect on the mutagenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and 67.9%, 66.8%, 64.6% and 56% inhibition on the mutagenesis by 4-nitroquinoline-1-oxide(4NQO) against TA100 strain, whereas 70.2%, 60.9%, 61.9% and 52.8% inhibitions were observed on the mutagenesis induced by 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indol(Trp-P-1) in the presence of 200㎍/plate. TA100 strain was more sensitive than TA98 strain by four kinds of extracts on antimutagenesis. The effects of Ligularia fischeri extracts on the frequencies of micronucleated poly chromatic erythrocytes(MNPECs) induced by MNNG were investigated in the bone marrow. Ten, 20, 40 and 80mg g/kg of each extract were administered to animals immediately after injection of MNNG and the exposure time was 36 hours. Inhibitory effects of Ligularia fischeri ethanol extracts were 12%, 35.3%, 58.8%, and 57%, in the presence of 20, 40, 60 and 80mg/kg, respectively whereas methanol extracts showed 15.5%, 32.7%, 50.8%, and 57.9% inhibitory effects, respectively. Both extracts showed enhanced antimutagenic and antigenotoxic effects. These results showed a good correlation between antimutagenic effects in in vitro and in in vitro assay.

• The Plant Pathology Journal
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• v.20 no.3
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• pp.229-233
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• 2004

The bacterial leaf blight, which is caused by Xantho-monas oryzae pv. oryzae, is the most damaging and intractable disease of rice. To identify the genes involved in the virulence mechanism of transposon TnS complex, which possesses a linearized transposon and transposase, was successfully introduced into X. oryzae pv. oryzae by electroporation. The transposon mutants were selected and confirm the presence of transposition in X. oryzae pv. oryzae by the PCR amplification of transposon fragments and the Southern hybridization using these mutants. Furthermore, transposon insertion sites in the mutant bacterial chromosome were deter-mined by direct genomic DNA sequencing using transposon-specific primers with ABI 3100 Genetic Analyzer. Efficiency of transposition was influenced mostly by the competence status of X. oryzae pv. oryzae cells and the conditions of electroporation. These results indicated that the insertion mutagenesis strategy could be applied to define function of uncharacterized genes in X. oryzae pv. oryzae.

• BMB Reports
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• v.49 no.6
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• pp.349-354
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• 2016

The archaeon Sulfolobus solfataricus P1 carboxylesterase is a thermostable enzyme with a molecular mass of 33.5 kDa belonging to the mammalian hormone-sensitive lipase (HSL) family. In our previous study, we purified the enzyme and suggested the expected amino acids related to its catalysis by chemical modification and a sequence homology search. For further validating these amino acids in this study, we modified them using site-directed mutagenesis and examined the activity of the mutant enzymes using spectrophotometric analysis and then estimated by homology modeling and fluorescence analysis. As a result, it was identified that Ser151, Asp244, and His274 consist of a catalytic triad, and Gly80, Gly81, and Ala152 compose an oxyanion hole of the enzyme. In addition, it was also determined that the cysteine residues are located near the active site or at the positions inducing any conformational changes of the enzyme by their replacement with serine residues.

• Korean Journal Plant Pathology
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• v.11 no.3
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• pp.265-270
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• 1995

Transposon mutation of Xanthomonas campestris pv. vesicatoria (Xcv) was induced by using transposon omegon ($\Omega$)-Km (Tn $\Omega$Km), which was confirmed by resistance to kanamycin (KMr), and nonpathogenic mutants were selected through the inoculation test on pepper plants. The mutagenesis frequency was about 6$\times$10-8, and 53 out of 2,000 Kmr bacterial colonies tested were nonpathogenic to the pepper cultivar Cheung-Hong. Optimum conditions for the Tn $\Omega$Km mutagenesis of Xcv were Luria Bertani (LB) broth medium for culture of Xcv, yeast extract-dextrose-CaCO3 (YDC) agar medium for selection of Tn $\Omega$Km-mediated mutants, and over 1 to 2 in the ratio of the donor (Escherichia coli S17-1 with the plasmid pJFF350 $\Omega$Km) and the recipient (Xcv) in the culture for the mutagenesis. One of the 4 nonpathogenic mutants (WNP1, WNP3, WNP4 and WNP5), which had been reconfirmed through the inoculation on pepper cv. Dabokgun, showed no differences in the production of exoenzymes such as protease and polygalacturonase and extracellular polysaccharides in vitro and the bacterial growth rate from those of the wild type of Xcv.

• BMB Reports
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• v.31 no.3
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• pp.254-257
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• 1998

The gshI gene from the Escherichia coli K-12 strain codes for ${\gamma}-glutamylcysteine$ synthetase which mediates the rate-limiting step of glutathione biosynthesis. The isolated gshI gene from E. coli K-12 has an unusual translation initiation codon, UUG. The 494th amino acid is Ala rather than Gly which was found in a mutant strain E. coli B. In order to improve the translational rate of the gshI gene of E. coli K-12, the initiation codon, UUG, was changed to the usual AUG codon by the site-specific mutagenesis. This change has resulted in a 53% increase of ${\gamma}-glutamylcysteine$ synthetase activity. The enzyme activity was also improved by replacing $Ala^{494}$ with Val (A494V) or Leu (A494L). The replacement of $Ser^{495}$ with Thr (S495T) also resulted in a 62% increase of the enzyme activity. Therefore, the specific activity of ${\gamma}-glutamylcysteine$ synthetase was increased with the increasing chain length of the aliphathic amino acid at the site of the 494th amino acid (Ala<$Val{\leq}Leu$).

• Biomolecules & Therapeutics
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• v.11 no.2
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• pp.139-144
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• 2003

Ganoderma lucidum is commonly known as medically potent mushroom, which has been widely used in China and other oriental countries for the treatment of various diseases, including cancer. In this report, we investigated the anti-oxidant and protective effect of Ganodema lucidum extract (GLE) against the DNA damage induced by free radical and U.V. In the assay of cell growth inhibition, the inhibitory cell growth rate induced by hydroxyl radical was dose-dependently decreased by GLE. This results support that GLE has a detoxifying activity against cytotoxicity of hydroxyl radical in E. coli cell. GLE also protected ColE1 plasmid DNA damage in the concentration of 200$\mu\textrm{g}$ per reaction on the DNA fragmentation assay. The nuclear tailing by hydrogen peroxide in single cell gel electrophoresis(SCGE) was decreased by GLE in the concentration of 50$\mu\textrm{g}$/ml. These data indicate that Ganoderma lucidum has an anti-oxidative activity to hydrogen peroxide. The mutation rate after irradiation of U.V. was reduced by 50$\mu\textrm{g}$/ml GLE and total number of Rif (Rifampicin) resistant mutants was decreased in a concentration dependent manner when added the GLE exogenously in a culture media. According to the results, it is likely that GLE has not only an anti-oxidative activity to hydroxyl radical but also an anti-mutagenic activity to U.V. mutagenesis.

• BMB Reports
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• v.34 no.2
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• pp.172-175
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• 2001

Catechol 1,2-dioxygenase $I_1$ ($CDI_1$) is the first enzyme of the $\beta$-ketoadipate pathway in Acinetobacter lowffii K24. $CDI_1$ has two cysteines (155, 202) and its enzyme activity is inhibited by the cysteine inhibitor, $AgNO_3$. Two mutants, $CDI_1$ C155V and $CDI_1$ C202V, were obtained by site-directed mutagenesis. The two mutants were overexpressed and the mutated amino acid residues (Cys$\rightarrow$Val) were characterized by peptide mapping and amino acid sequencing. Interestingly, $CDI_1$ C155V was inhibited by $AgNO_3$, whereas $CDI_1$ C202V was not inhibited. This suggests that $Cys^{202}$ is the sole inhibition site by $AgNO_3$ and is close to the active site of the enzyme. However, the results of the biochemical assay of mutated $CDI_1s$ suggest that the two cysteines are not directly involved in the activity of the catechol 1,2-dioxygenase of $CDI_1$.