• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.11-16
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• 2009

Magnaporthe oryzae, the causal agent of rice blast, forms a specialized infection structure, called an appressorium, which is crucial for penetration and infection of the host plant. Pharmacological data suggest that calcium/calmodulindependent signaling is involved in appressorium formation in this fungus. To understand the role of the calcium/calmodulin-activated protein phosphatase on appressorium formation at the molecular level, MCNA, a gene encoding the catalytic subunit of calcineurin, was functionally characterized in M. oryzae. Transformants expressing sense/antisense RNA of MCNA exhibited significant reductions in mycelial growth, conidiation, appressorium formation, and pathogenicity. cDNA of MCNA functionally complemented a calcineurin disruptant strain (cmp1::LEU2 cmp2::HIS3) of Saccharomyces cerevisiae. These data suggest that calcineurin A plays important roles in signal transduction pathways involved in the infection-related morphogenesis and pathogenicity of M. oryzae.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.75-81
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• 2006

A full-length cDNA encoding dihydroflavonol 4-reductase (st-dfr) of potato was isolated by rapid amplification of cDNA ends, and their expression was investigated from purple-fleshed potato (Solanum tuberosum L. cv. Jashim). The st-dfr exists as a member of a small gene family and its transcripts was abundant in the order of tuber flesh, stem, leaf, and root. The expressions of st-dfr gene were light inducible and cultivar dependant. Transgenic potato plants harboring antisense st-dfr (AS-DFR) sequences were analyzed. The accumulation of mRNA was nearly completely inhibited as a result of introducing an AS-DFR gene under the control of the 35S CaMV promoter into the red tuber skin Solanum tuberosum L. cv. Desiree. The anthocyanin content of the tuber peels of the transgenic lines was dramatically decreased by up to 70%. The possible production of flavonols in the peels of AS-DFR transgenic potatoes was discussed.

• Molecules and Cells
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• v.22 no.1
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• pp.30-35
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• 2006

Munc18, a mammalian homolog of C. elegans Unc, is essential for neurotransmitter release. The aim of this study was to identify estrogen-dependent expression of Munc18-1 and its role in the regulation of glutamate release for puberty onset. Hypothalamic munc18-1 mRNA levels were significantly increased by estrogen treatment in ovariectomized, immature female rats. During pubertal development, the munc18-1 mRNA levels dramatically increased between the juvenile period and the anestrous phase of puberty. Intracerebroventricular administration of an antisense oligodeoxynucleotide against munc18-1 mRNA significantly decreased glutamate release and delayed the day of puberty onset. These results suggest that Munc18-1, expressed in an estrogen-dependent manner, plays an important role in the onset of female puberty via the regulation of glutamate release.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.1-11
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• 2001

New technologies will have a large impact on the discovery of new herbicide site of action. Genomics, combinatorial chemistry, and bioinformatics help take advantage of serendipity through tile sequencing of huge numbers of genes or the synthesis of large numbers of chemical compounds. There are approximately $10^{30}\;to\;10^{50}$ possible molecules in molecular space of which only a fraction have been synthesized. Combining this potential with having access to 50,000 plant genes in the future elevates tile probability of discovering flew herbicidal site of actions. If 0.1, 1.0 or 10% of total genes in a typical plant are valid for herbicide target, a plant with 50,000 genes would provide about 50, 500, and 5,000 targets, respectively. However, only 11 herbicide targets have been identified and commercialized. The successful design of novel herbicides depends on careful consideration of a number of factors including target enzyme selections and validations, inhibitor designs, and the metabolic fates. Biochemical information can be used to identify enzymes which produce lethal phenotypes. The identification of a lethal target site is an important step to this approach. An examination of the characteristics of known targets provides of crucial insight as to the definition of a lethal target. Recently, antisense RNA suppression of an enzyme translation has been used to determine the genes required for toxicity and offers a strategy for identifying lethal target sites. After the identification of a lethal target, detailed knowledge such as the enzyme kinetics and the protein structure may be used to design potent inhibitors. Various types of inhibitors may be designed for a given enzyme. Strategies for the selection of new enzyme targets giving the desired physiological response upon partial inhibition include identification of chemical leads, lethal mutants and the use of antisense technology. Enzyme inhibitors having agrochemical utility can be categorized into six major groups: ground-state analogues, group specific reagents, affinity labels, suicide substrates, reaction intermediate analogues, and extraneous site inhibitors. In this review, examples of each category, and their advantages and disadvantages, will be discussed. The target identification and construction of a potent inhibitor, in itself, may not lead to develop an effective herbicide. The desired in vivo activity, uptake and translocation, and metabolism of the inhibitor should be studied in detail to assess the full potential of the target. Strategies for delivery of the compound to the target enzyme and avoidance of premature detoxification may include a proherbicidal approach, especially when inhibitors are highly charged or when selective detoxification or activation can be exploited. Utilization of differences in detoxification or activation between weeds and crops may lead to enhance selectivity. Without a full appreciation of each of these facets of herbicide design, the chances for success with the target or enzyme-driven approach are reduced.

• Journal of Plant Biotechnology
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• v.38 no.1
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• pp.54-61
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• 2011

Antisense construct of cDNA for senescencerelated ACC oxidase (CAO) cDNA isolated from carnation flowers were introduced into tobacco by Agrobacteriummediated transformation. The decreasing expression of NtACO and the reduction of ethylene production were observed in these transgenic lines. In contrast, the SAMDC transcripts and spermidine content were increased. The findings that higher content of spermidine in the ethylene suppressed transgenic plants compared with wild-type should be directly resulted in the enhancement of SAMDC activity followed by the increased accumulation of SAMDC transcript. To investigate the pathogenic response in these transgenic plants, wild-type and transgenic plants were inoculated with Phytophthora parasitica pv. nicotianae. Transgenic plants suppressing ethylene production showed the increased resistance against fungal pathogen, comparing with wild-type plant. PR-protein genes expression in CAO-AS-2 and CAOAS-4 were also higher at the normal growth condition and pathogenic response than in wild-type plants. The results of higher spermidine content and SAMDC activity in transgenic plants, CAO-AS-2 and CAO-AS-4, support the possibility that an increase in spermidine content might induce the higher transcripts of PR-protein genes. This results agreed with the phenomena that spermidine promoted the expression of PR1a and a SAMDC inhibitor, MGBG, decreased the expression of PR1a in leaf discs. These results suggest that the resistance against fungal pathogen in transgenic tobacco impaired in ethylene production might be caused by increasing in polyamine, especially spermidine, biosynthesis.

• The Korean Journal of Zoology
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• v.39 no.4
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• pp.352-361
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• 1996

The c-myc proto-onco9ene, one of the immediately early genes, is involved in ceflular proliferation and differentiation, and its biologleal function is regulated hy dimerization with a heterodimeric partner, myn. In the present study, gene expression patterns of c-myc and myn during mouse preimplantation embryo development were examined using a semi-quantitative reverse transcription-poiymerase chain reaction (RT-PCR). Myn transcripts were rather constitutively expressed throughout embryonic stages with a slight increase only at biastocyst stage. in contrast, expression of c-myc transcripts wm developmental stage-'pedfic. The c-myc transcripts were detected at 1-cell stage, declined abruptly at 2-cell stage and then increased gradually at blastocyst stage. To examine the possible role of myn during preimpiantation mouse embryo development, two myn antisense oligonucleotides spanning the tail of zipper dognain (myn2; 20-mer) and the second helix domain (myn3; 20-mer) were microinjected into the fertilized 1-cellembryos. Microinjection of myn2 and myn3 resulted in developmental tion at morula/biastocyst transition stage, leading to the fiagentation of embryos. Talien together, these results suggest that c-myc and its heterodimeric partner, myn, are differentially expressed In a developmental stage-dependent manner, and myn may play an important role in mouse preimpiantation embryo development.

• 대한핵의학회:학술대회논문집
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• 2004.11a
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• pp.411.2-411.2
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• 2004

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.260.2-260
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• 1996

No Abstract, See Full Text

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2001.10b
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• pp.203-204
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• 2001

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.206.2-206
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• 1997

No Abstract, See Full Text