• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.457-461
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• 2005

During the last few years, considerable progresses have been made in understanding of roles and biosynthesis of ascorbic acid (AsA) in plants. The concentrations of ascorbic acid is 2-4 mM in leaf cells, but much higher at the chloroplast. There are three forms of ascorbic acid in the plant mainly ascorbic acid (AsA), monode­hydroascorbic acid (MDHA) and dehydroascorbic acid (DHA). AsA in plant cell performs antioxidants by changing those three forms. And AsA promotes cell division and elongation There was new pathway of ascorbic acid metabolism. It is called pathway of Smirnoff-Wheeler. This report will provide understanding of AsA in plants, and also provide

• Journal of Plant Biology
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• v.36 no.3
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• pp.251-257
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• 1993

The size variation of the cambial initials and their derivatives, in relation to the increase of girth, in the intact and decapitated stem of Populus euramericana was anatomically studied. In the typical nonstoried cambium of P. euramericana, the cell size of fusiform initials, vessel member, and sieve tube member were gradually increased and thus it reached a maximal state. In the intact plants, the size of the cambial initials and their derivatives was larger then in the decapitated ones. On the other hand, the frequency of anticlinal division of the cambial cells, the rate of the elongation and loss of the daughter initials in the intact plants was higher than in the decapitated ones. The cambium of the intact plants had higher ray compared with that of the decapitated ones. It was interpreted that these results were caused by the decapitation, which could block the supply of certain substances for cell growth such as hormones and metabolites.

• Biomolecules & Therapeutics
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• v.32 no.2
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• pp.231-239
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• 2024

Methyl anthranilate (MA) is a botanical fragrance used in food flavoring with unexplored potential in anti-pigment cosmetics. MA dose-dependently reduced melanin content without affecting cell viability, inhibited dendrite elongation and melanosome transfer in the co-culture system of human melanoma cells (MNT-1) and human keratinocyte cell line (HaCaT), and downregulated melanogenic genes, including tyrosinase, tyrosinase-related protein 1 and 2 (TRP-1, TRP-2). Additionally, MA decreased cyclic adenosine monophosphate (cAMP) production and exhibited a significant anti-pigmentary effect in Melanoderm^TM. These results suggest that MA is a promising anti-pigmentary agent for replacing or complementing existing anti-pigmentary cosmetics.

• Molecules and Cells
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• v.28 no.2
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• pp.93-98
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• 2009

A plant-specific gene was cloned from melon fruit. This gene was named downward leaf curling (CmDLC) based on the phenotype of transgenic Arabidopsis plants overexpressing the gene. This expression level of this gene was especially upregulated during melon fruit enlargement. Overexpression of CmDLC in Arabidopsis resulted in dwarfism and narrow, epinastically curled leaves. These phenotypes were found to be caused by a reduction in cell number and cell size on the adaxial and abaxial sides of the epidermis, with a greater reduction on the abaxial side of the leaves. These phenotypic characteristics, combined with the more wavy morphology of epidermal cells in overexpression lines, indicate that CmDLC overexpression affects cell elongation and cell morphology. To investigate intracellular protein localization, a CmDLC-GFP fusion protein was made and expressed in onion epidermal cells. This protein was observed to be preferentially localized close to the cell membrane. Thus, we report here a new plant-specific gene that is localized to the cell membrane and that controls leaf cell number, size and morphology.

• Proceedings of the Korean Society of Crop Science Conference
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• 2007.04a
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• pp.65-73
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• 2007

The objective of this study is to understand how regulatory mechanisms respond to sugar status for more efficient carbon utilization and source-sink regulation in plants. So, we need to identify and characterize many components of sugar-response pathways for a better understanding of sugar responses. For this end, genes responding change of sugar status were screened using Arabidpsis cDNA arrays, and confirmed thirty-six genes to be regulated by sucrose supply in detached leaves by RNA blot analysis. Eleven of them encoding proteins for amino acid metabolism and carbohydrate metabolism were repressed by sugars. The remaining genes induced by sugar supply were for protein synthesis including ribosomal proteins and elongation factors. Among them, I focused on three hydrolase genes encoding putative $\beta$-galactosidase, $\beta$-xylosidase, and $\beta$-glucosidase that were transcriptionally induced in sugar starvation. Homology search indicated that these enzymes were involved in hydrolysis of cell wall polysaccharides. In addition to my results, recent transcriptome analysis suggested multiple genes for cell wall degradation were induced by sugar starvation. Thus, I hypothesized that enzyme for cell wall degradation were synthesized and secreted to hydrolyze cell wall polysaccharides producing carbon source under sugar-starved conditions. In fact, the enzymatic activities of these three enzymes increased in culture medium of Arabidopsis suspension cells under sugar starvation. The $\beta$-galactosidase encoded by At5g56870 was identified as a secretory protein in culture medium of suspension cells by mass spectrometry analysis. This protein was specifically detected under sugar-starved condition with a specific antibody. Induction of these genes was repressed in suspension cells grown with galactose, xylose and glucose as well as with sucrose. In planta, expression of the genes and protein accumulation were detected when photosynthesis was inhibited. Glycosyl hydrolase activity against galactan also increased during sugar starvation. Further, contents of cell wall polysaccharides especially pectin and hemicellulose were markedly decreased associating with sugar starvation in detached leaves. The amount of monosaccharide in pectin and hemicellulose in detached leaves decreased in response to sugar starvation. These results supported my idea that cell wall has one of function to supply carbon source in addition to determination of cell shape and physical support of plant bodies.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.72.1-72
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• 2003

Generally, plants defend themselves against pathogens by structural and biochemical reactions. Defense structures act as physical barriers and inhibit the pathogen from gaining entrance and spreading through the plant. Xanthomonas axonopodis pv glycines, the causal pathogen of bacterial pustule of soybean, causes hypersensitive response (HR). When pepper fruits were inoculated with X. axonopodis pv. glycines, in situ, time-series defense-related structural changes occurred in the inoculated sites. Early responses were programmed cell death (PCD), characterized by condensation and vacuolization of the cytoplasm, condensation of nuclear materials, and fragmentation of the nuclear DNA, which were observed by transmission electron microscopy. Nuclear fragmentation was proven by TUNEL method under confocal laser scanning microscopy and DNA laddering through eletrophoresis. At later stages, plant responses were cell elongation and cell division, forming a periderm-like boundary layer that demarcated healthy tissues from the inoculation sites. Using several stains such as toluidine blue, sudan IV, annexin V, and phloroglucinol-HCl, defense-related materials and structural changes were also examined.

• BMB Reports
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• v.45 no.9
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• pp.521-525
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• 2012

In addition to its pivotal role in neuronal survival, PI3K/Akt signaling is integral to neuronal differentiation and neurite outgrowth. However, the exact role of Akt in neuronal differentiation is still controversial. Here, we found that nuclear expression of CA-Akt resulted in unusual rapid neurite outgrowth and overexpression of KD-Akt caused multiple dendrite growth without specific axon elongation. Moreover, microarray data revealed that the expression of FOXQ1 expression was about 10-fold higher in cells with nuclear, active Akt than in control cells. Quantitative real-time PCR analysis showed that mRNA levels were upregulated in NLS-CA-Akt cells as compared to KD or EV cells. Furthermore, our FACS analysis demonstrated that overexpression of NLS-CA-Akt accumulate cells in the G1 phase within 24 h, fitting with the rapid sprouting of neuritis. Thus, our data implied that at least in this early time frame, the overexpression of nuclear, active Akt forced cells into neurite development through probably FOXQ1regulation.

• Journal of Ginseng Research
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• v.16 no.1
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• pp.37-43
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• 1992

Structural changes of the endosperm of Panax ginseng C.A. Meyer from fertilization to germination were investigated by light microscope. The endosperm of the ginseng seed is cellular type. Since endosperm cells adjacent embryo continuously breakdown and disappear with the elongation of embryo, the real of endosperm is gradually decreased. As the anatropous ovules of immature seed with green seed coat developes more and more, ovary cells adjacent ovary cavity become abundant by the periclinal division, their size is decreased, hypotrophy of cell wall discern, and they are gradually differentiated in seed coat. Though embryo responds strongly to basic dye at the stage of completion of endosperm formation, tissue of endosperm responds to acidic dye positively Cell wall of embryo and endosperm are composed of primary cell wall not lignified. Endosperm cells adjacent embryo begin to breakdown in the endosperm tissue of indehiscent seed before the beginning of the after-ripening. Dehiscent seed of which seed coat is opened through after-ripening represent the form as a seedling in the result of embryo developments with the formation of organs; radicle, cotyledon, plumule. Umbilifom layer represents strong positive response to the toluidine blue and the basic function. Umbiliform layer that endosperm cells breakdown and disappear is observed clearly at the periphery of the embryo cotylemon, while slightly at the periphery of the radicle.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.1994-1998
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• 2017

FtsZ, a bacterial cell-division protein, is an attractive antibacterial target. In the screening for an inhibitor of Staphylococcus aureus FtsZ, madurahydroxylactone (1) and its related derivatives 2-5 were isolated from Nonomuraea sp. AN100570. Compound 1 inhibited S. aureus FtsZ with an $IC_{50}$ of $53.4{\mu}M$ and showed potent antibacterial activity against S. aureus and MRSA with an MIC of $1{\mu}g/ml$, whereas 2-5 were weak or inactive. Importantly, 1 induced cell elongation in the cell division phenotype assay, whereas 2-5 did not. It indicates that 1 exhibits its potent antibacterial activity via inhibition of FtsZ, and the hydroxyl group and hydroxylactone ring of 1 are critical for the activity. Thus, madurahydroxylactone is a new type of inhibitor of FtsZ.

• The Plant Pathology Journal
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• v.30 no.2
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• pp.215-219
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• 2014

The GacS/GacA two component system regulates various traits related to the biocontrol potential of plant-associated pseudomonads. The role of the sensor kinase, GacS, differs between strains in regulation of motility. In this study, we determined how a gacS mutation changed cell morphology and motility in Pseudomonas chlororaphis O6. The gacS mutant cells were elongated in stationary-phase compared to the wild type and the complemented gacS mutant, but cells did not differ in length in logarithmic phase. The gacS mutant had a two-fold increase in the number of flagella compared with the wild type strain; flagella number was restored to that of the wild type in the complemented gacS mutant. The more highly flagellated gacS mutant cells had greater swimming motilities than that of the wild type strain. Enhanced flagella formation in the gacS mutant correlated with increased expression of three genes, fleQ, fliQ and flhF, involved in flagellar formation. Expression of these genes in the complemented gacS mutant was similar to that of the wild type. These findings show that this root-colonizing pseudomonad adjusts flagella formation and cell morphology in stationary-phase using GacS as a major regulator.