• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.363-368
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• 2017

Methylotrophy is able to use reduced one-carbon compound, such as methanol and methylamine, as a sole carbon source. Methylobacterium extorquens AM1 is the most extensively studied methylotroph utilizing serine-isocitrate lyase cycle. Because the Poly 3-hydroxybutyrate (PHB) synthesis pathway in M. extorquens AM1 is likely to interlink with EMCP (ethylmalonyl-CoA pathway), glyoxylate, and TCA cycles, regulation of PHB production is needed to produce EMCP-derived acid or TCA acids. To adjust carbon flux to PHB production, PhaR, which seems to have function of regulator of PHB synthesis and acetyl-CoA flux, was knocked out in M. extorquens AM1 by using markerless gene deletion methods. As a result, PHB granules were remarkably reduced in the knockout strain ${\Delta}phaR$ compared to parental strain. Although lag phase was extended for 12h, ${\Delta}phaR$ showed similar cell growth and methanol consumption rate compared to wild type.

• Korean Journal of Agricultural Science
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• v.25 no.1
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• pp.68-78
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• 1998

To investigate the genetic polymorphisms and constitutions of blood proteins and enzymes in the Korean native cattle population of National Livestock Cooperatives Federation(NLCF), the genetic variants of transferrin(Tf), post-transferrin-2(pTf-2), albumin(Alb), post-albumin(pAlb), ceruloplasmin(Cp), amylase-I(Am-I) and herroglobin(Hb) were analyzed using the PAGE(polyacrylamide gel electrophoresis) and ST AGE(starch gel electrophoresis) methods. On the genetic variants of the serum proteins, the transferrin(Tf) locus was assumed to be genetically controlled by codominant alleles, Tf A, $D_1$, $D_2$ and E alleles, and the gene frequencies of these were 0.249, 0.248, 0.260 and 0.243, respectively. The post-transferrin locus was observed to be controlled by pTf-2 F and S alleles, and the gene frequencies of these were 0.662 and 0.338, respectively. The post-albumin(pAlb) loci were identified to be controlled by two alleles, pAlb F and S alleles for pAlb locus, and the gene frequncies of these were 0.440 and 0.560 for pAlb F and S alleles, respectively. On the genetic variants of the serum enzymes, ceruloplasmin(Cp) and amylase-I(Am-I) loci were found to be controlled by two alleles, Cp F and S for Cp locus, and Am-I B and C for Am-I locus, and gene frequencies of these were 0.319 and 0.681 for Cp F and S, and 0.871 and 0.120 for Am-I Band C, respectively. On the genetic variants of the hemoglobin(Hb), the distributions of genotypes were 76.5, 21.2 and 2.3% for Hb AA, AB and BB types, and the gene frequnecies for Hb A and B were 0.871 and 0.129, respectively. On the effects of genetic variants of blood proteins, Tf $D_1D_1$, $D_2D_2$ and $D_2E$ genotypes were significantly higher on body weight at 6 month and average daily gain than that of other Tf genotypes.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.69-81
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• 1995

This study was conducted to examine the genetic variants of the blood proteins and enzymes in beef cattle breeds, Hereford, Angus and Sharolais reared at the Daekwanryuong Branch of the National Livestock Research Institute. Genetic polymorphisms of transferrin(Tf), post-transferrin2(pTf-2), albumin(Alb), post-albumin (pAlb), ceruloplasmin(Cp), amylase-I(Am-I) and hemoglobin(Hb) in blood were analyzed by the methods of PAGE(polyacrylamide gel electrophoresis) and STAGE(starch gel electrophoresis). The results obtained from this study were summarized as follows: 1. Tf and pTf-2 locus assumed to be controlled by codominant alleles, A. $D_1$, $D_2$ and E allele for Tf, F and S allele for pTf-2. In genotype frequencies, 25% and 90% for Tf $D_1D_2$ and pTf-2 SS in Hereford, 25% and 100% for Tf $AD_1$ and pTf-2 FF in Angus, 50% for Tf $D_1D_1$ and pTf-2 FS in Sharolais were found to have the highest frequency, respectively. In gene frequencies, 0.400 and 0.900 for Tf E and pTf-2 S allele in Hereford, 0.678 and 0.607 for Tf $D_1$ and pTf-2S in Sharolais were appeared to have the highest frequency. 2. Alb and pAlb locus assumed to be controlled by codominant alleles, only A allele for Alb, F and S allele for pAlb. In genotype frequencies, 70% for pAlb SS in Hereford, 90% for pAlb FF in Angus and 57.15% for pAlb SS in Sharolais were found to have the highest frequency. In gene frequencies, 0.825 and 0.750 for pAlb S in Hereford and Charolais, 0.900 for pAlb F in Angus were found to have the highest frequency. 3. Cp and Am-I locus appeared to be controlled by two alleles, F and S allele for Cp, B and C allele for Am-I. In genotype frequencies, 100% and 65% for Cp FF and Am-I BB in Hereford, 45% and 85% for Cp FF, and Am-I CC in Angus, 50% and 64.29% for Cp FF and Am-I BC in Sharolais were found to have the highest frequency. Gene frequencies were 1,000, 0.600 and 0.750 for Cp F in Herehord, Angus and Sharolais, 0.800, 0.875 and 0.680 for Am-I B, C and C allele in Hereford, Angus and sharolais, respectively. 4. Hb locus assumed to be controlled by codominant alleles, only A allele in Hereford and Angus, A and B allele in Sharolais. Genotype frequencies were 57.14% and 42.86% for Hb AA and AB in Sharolais, and gene frequencies were 0.785 and 0.215 for Hb A and B in Sharolais.

• Horticultural Science & Technology
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• v.30 no.2
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• pp.162-170
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• 2012

The objectives of this study were to isolate and the sequence of novel $F3'H$ gene related to an anthocyanin pathway, and to confirm the expression patterns of the gene involved in the flower color variations of chrysanthemum mutants. In this study, we isolated the full-length cDNAs and the genomic DNAs of an $F3'H$ gene from a wild type (WT) chrysanthemum (cv. Argus) and its three color mutants. The sequence analysis revealed a putative open reading frame of 1,527 bp that encodes a polypeptide of 509 amino acids. Sequence homology ranged from 97% to 99% between 'Argus' and its three color mutants. The sequence analysis from the genomic DNA revealed that the chrysanthemum $DgF3'H$ gene consisted of three exons and two introns spanning a 3,830 bp length. The sizes of the gene for three mutants ranged from a shorter size of 3,828 bp to a longer size of 3,838 bp when compared to the size of WT. The total size of the two introns was 2,157 bp for WT, but those for three color mutants ranged from 2,154 bp to 2,159 bp. A result of an RT-PCR analysis indicated that the color variations of the mutants AM1 and AM2 can be partly explained by the structural modification derived from the sequencial changes in the gene caused by gamma ray. A Southern blot analysis revealed that the $DgF3'H$ gene existing as multiple copies in the chrysanthemum genome. A systemic study will be further needed to provide a genetic mechanism responsible for the color mutation and to uncover any involvement of genetic elements for the expression of the $DgF3'H$ gene for the color variation in chrysanthemum.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.346-356
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• 2011

BACKGROUND: Chemical fungicides not only may pollute the ecosystem but also can be environmentally hazardous, as the chemicals accumulate in soil. Biological control is a frequently-used environment-friendly alternative to chemical pesticides in phytopathogen management. However, the use of microbial products as fungicides has limitations. This study isolated and characterized a three-antifungal-enzyme (chitinase, cellulase, and ${\beta}$-1,3-glucanase)-producing bacterium, and examined the conditions required to optimize the production of the antifungal enzymes. METHOD AND RESULTS: The antifungal enzymes chitinase, cellulase, and ${\beta}$-1,3-glucanase were produced by bacteria isolated from an sawmill in Korea. Based on the 16S ribosomal DNA sequence analysis, the bacterial strain AM50 was identical to Streptomyces sp. And their antifungal activity was optimized when Streptomyces sp. AM50 was grown aerobically in a medium composed of 0.4% chitin, 0.4% starch, 0.2% ammonium sulfate, 0.11% $Na_2HPO_4$, 0.07% $KH_2PO_4$, 0.0001% $MgSO_4$, and 0.0001% $MnSO_4$ at $30^{\circ}C$. A culture broth of Streptomyces sp. AM50 showed antifungal activity towards the hyphae of plant pathogenic fungi, including hyphae swelling and lysis in P. capsici, factors that may contribute to its suppression of plant pathogenic fungi. CONCLUSION(S): This study demonstrated the multiantifungal enzyme production by Streptomyces sp. AM50 for the biological control of major plant pathogens. Further studies will investigate the synergistic effect, to the growth regulations by biogenic amines and antifungal enzyme gene promoter.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.31-39
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• 2007

This study has been carried out for investigating the relatedness of representative 135 Shigella sonnei strains isolated from 2000 to 2004 by using biotyping and antimicrobial resistance. All strains showed typical biochemical characterisics of Shigella strain. Among 135 strains,79 (58.5%) strains were biotype "g",54 (40.0%) strains were biotype "a" and 2 (1.5%) strains were biotype "e". The results of susceptibility test against 16 antimicrobial agents were like this. Most of strains were susceptible to AN, CIP, C and GM. 129 (95.6%) strains were resistant to SXT, 126 (93.3%) strains were resistant to TE and 122 (90.4%) strains were resistant to SM. One hundred thirty two (97.8%) strains were resistant to more than two antimicrobial agents. R28 type (antimicrobial resistance patterns 28: resistant to AM, SAM, TE, TIC, SXT, K, SM and AmC) were 42 strains (31.1%). The other strains were showed 33 kinds of R patterns. The results of $bla_{TEM}$, sulII, tetA and strA gene detection were coincided with phenotype of antimicrobial resistance by disk diffusion method. But some strains which had sulII and strA genes were not showed the resistance against SXT and SM.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1451-1489
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• 2002

Sphingosine is known to regulate a wide range of cell physiology including growth, differentiation, and apoptosis. In this study, we examined the effect of sphingosine on the phospholipase D (PLD) activity in rat thymocytes. Sphingosine potently stimulated PLD in the absence of extracellular calcium, while depletion of intracellular calcium by BAPTA/AM treatment completely blocked activation of PLD by sphingosine. Sphingosine-induced increase of the intracellular calcium concentration was confirmed using a fluorescent calcium indicator Fluo-3/AM. A phosphoinositide-specific phospholipase C inhibitor U73122 partially inhibited the stimulation of PLD by sphingosine. When mouse PLD2 gene was transfected into mouse thymoma EL4 cells, which lack intrinsic PLD activity, sphingosine could stimulate PLD2 significantly while overexpression of human PLD1 had no effect. Taken together, the sphingosine-stimulated PLD activity in rat thymocytes is dependent on the mobilization of intracellular calcium and appears to be due to the PLD2 isoform.

• Clinical and Experimental Reproductive Medicine
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• v.40 no.4
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• pp.155-162
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• 2013

Objective: Stress is known to be an inhibitor of the reproductive hypothalamic-pituitary-gonadal (HPG) axis. However, the neural and molecular connections between stress and reproduction are not yet understood. It is well established that in both humans and rodents, kisspeptin (encoded by the kiss1 gene) is a strong stimulator of the HPG axis. In the present study we hypothesized that endocannabinoids, an important neuromodulatory system in the brain, can act on the HPG axis at the level of kiss1 expression to inhibit reproductive function under stress. Methods: Adult male Wistar rats were unilaterally implanted with an intracerebroventricular cannula. Afterwards, the animals were exposed to immobilization stress, with or without the presence of the cannabinoid CB1 receptor antagonist AM251 (1 ${\mu}g/rat$). Blood samples were collected through a retro-orbital plexus puncture before and after stress. Five hours after the stress, brain tissue was collected for reverse transcriptase-quantitative polymerase chain reaction measurements of kiss1 mRNA. Results: Immobilization stress (1 hour) resulted in a decrease in the serum luteinizing hormone concentration. Additionally, kiss1 gene expression was decreased in key hypothalamic nuclei that regulate gonadotrophin secretion, the medial preoptic area (mPOA), and to some extent the arcuate nucleus (ARC). A single central administration of AM251 was effective in blocking these inhibitory responses. Conclusion: These findings suggest that endocannabinoids mediate, at least in part, immobilization stress-induced inhibition of the reproductive system. Our data suggest that the connection between immobilization stress and the HPG axis is kiss1 expression in the mPOA rather than the ARC.

• The Plant Pathology Journal
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• v.19 no.1
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• pp.51-56
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• 2003

Rehmannia glutinosa is one of the most important medicinal crops in Korea. However, various plant pathogens, including Fusatium spp., cause great damage on R. glutinosa and result in enormous economic losses. This study was conducted to breed Fusarium-resistant plants by using Agrobacterium tumefaciences and AFP (anti-fungal protein) gene. The plant material used was a native accession of R. glutinosa. The PCR analysis was conducted to verify transgenicity. Based on the PCR analysis, nptII band was observed in transgenic plant genome. Southern blot and AFP protein analyses also showed the expression of this gene in transgenic plants. Expression of AFP in transgenic plants offers the possibility of developing resistance to fungal infection.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.1-11
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• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.