• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.84.2-85
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• 2003

Magnaporthee grisea causes the devastating blast disease of rice. Entensive research has been conducted on infection mechanisms, particularly on appressorium formation and penetration, of this fungus during the last decade. However, the role(s) of cell-wall-degrading enzymes (CWDEs) on pathogenesis is not clearly demonstrated at molecular level. Many CWDES in plant pathogenic fungi including M. grisea are redundant; that is, there are multiple genes encoding enzymes with a similar or overlapping spectrum of activities. It is laborious to isolate all of the genes encoding related enzymes and to construct mutants lacking all 9f them. Thus, we considered alternative strategies to address the role of CWDEs in pathogenesis. Since expression of CWDE genes Is repressed by a simple sugar, as the first step, we cloned a Snfl (sucrose non-fermenting) gene (MgSnf1) from M. grisea. The predicted amino acid sequence showed a high identity with other Snf1 genes from various fungi. To elucidate molecular function of MgSnf1, a transformant lacking MgSnf1 was created by targeted gene replacement. En glucose, sucrose, and xylan the MgSnf1 mutant grew normally but in pectin and complex media, it grew slower than wild type. Expression of various CWDEs in MgSnf1 mutant was investigated and found that expression of some CWDEs is repressed. However, no significant difference was observed in conidial germination, appressorium formation, and pathogenicity in MgSnf1 mutant. However, MgSnf1 functionally complemented a yeast MgSnf1 mutant. These results suggest that MgSnf1 is involved in regulation of CWDEs and MgSnf1 is dispensable in pathogenicity of M. grisea.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1717-1722
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• 2008

The 70 kDa heat-shock protein (Hsp70) involved in various cellular functions, such as protein folding, translocation and degradation, regulates apoptosis in cancer cells. Recently, it has been reported that the green tea flavonoid (−)-epigallocatechin 3-gallate (EGCG) induces apoptosis in numerous cancer cell lines and could inhibit the anti-apoptotic effect of human Hsp70 ATPase domain (hATPase). In the present study, docking model between EGCG and hATPase was determined using automated docking study. Epi-gallo moiety in EGCG participated in hydrogen bonds with side chain of K71 and T204, and has metal chelating interaction with hATPase. Hydroxyl group of catechin moiety also participated in metal chelating hydrogen bond. Gallate moiety had two hydrogen bondings with side chains of E268 and K271, and hydrophobic interaction with Y15. Based on this docking model, we determined two pharmacophore maps consisted of six or seven features, including three or four hydrogen bonding acceptors, two hydrogen bonding donors, and one lipophilic. We searched a flavonoid database including 23 naturally occurring flavonoids and 10 polyphenolic flavonoids with two maps, and myricetin and GC were hit by map I. Three hydroxyl groups of B-ring in myricetin and gallo moiety of GC formed important hydrogen bonds with hATPase. 7-OH of A-ring in myricetin and OH group of catechin moiety in GC are hydrogen bond donors similar to gallate moiety in EGCG. From these results, it can be proposed that myricetin and GC can be potent inhibitors of hATPase. This study will be helpful to understand the mechanism of inhibition of hATPase by EGCG and give insights to develop potent inhibitors of hATPase.

• Journal of Ginseng Research
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• v.38 no.4
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• pp.289-292
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• 2014

Ginseng leaf/stem extract produced by subcritical water extraction at high temperature ($190^{\circ}C$) posses higher cytotoxic activity against human cancer cell lines than ethanol extract. Subcritical water extraction can be a great candidate for extraction of functional substance from ginseng leaves/stems.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.6
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• pp.267-272
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• 2016

Microscope cell image is an important indicator for obtaining the biological information in a bio-informatics fields. Since human observers have been examining the cell image with microscope, a lot of time and high concentration are required to analyze cell images. Furthermore, It is difficult for the human eye to quantify objectively features in cell images. In this study, we developed HCS algorithm for automatic analysis of cell image using an OpenCV library. HCS algorithm contains the cell image preprocessing, cell counting, cell cycle and mitotic index analysis algorithm. We used human cancer cell (MKN-28) obtained by the confocal laser microscope for image analysis. We compare the value of cell counting to imageJ and to a professional observer to evaluate our algorithm performance. The experimental results showed that the average accuracy of our algorithm is 99.7%.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2577-2583
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• 2011

We have designed a 20-residue hybrid peptide CA(1-8)-MA(1-12) (CAMA) incorporating residues 1-8 of cecropin A (CA) and residues 1-12 of magainin 2 (MA) with high bacterial cell selectivity. CAMA-P2 is an ${\alpha}$-helical antimicrobial peptide designed from a CAMA hybrid peptide and substitution of Gly-Ile-Gly hinge sequence of CAMA to Pro influences the flexibility at central part of CAMA. Based on structure-activity relationships of CAMA peptides, to investigate the effects of the total positive charges on antimicrobial activity of CAMA-P2, the $Ser^{14}{\rightarrow}$Lys analogue (CAMA-syn1) was synthesized. The role of tryptophan at C-terminal ${\alpha}$-helix on its antimicrobial activity as well as synergistic activity was also investigated using $Ser^{14}{\rightarrow}$Lys/$Phe^{18}{\rightarrow}$Trp analogue (CAMA-syn2). Also, we designed CAMA-syn3 by substitution of $Lys^{16}$ located opposite side of substituted $Lys^{14}$ of CAMA-syn1 with Leu residue, resulting in increase of hydrophobicity and amphipathicity of the peptide. All of CAMA-syn analogues showed good antimicrobial activities similar to those of CAMA and CAMA-P2. The CAMA-syn1 and CAMA-syn2 showed low hemolytic activity and cytotoxicity against human keratinocyte Haca-T cells while CAMA-syn3 showed hemolytic activity and cytotoxicity at its MIC value. We then investigated their abilities to act synergistically in combination with the antimicrobial flavonoids and synthetic compounds screened in our laboratory. The results showed that all peptides exhibited synergistic effects with dihydrobinetin, while only CAMA-syn2 exhibited synergistic effects with YKAs3001 against both S. aureus and MRSA, suggesting that Trp residue at C-terminus of CAMA-syn2 may facilitate the polar antibiotic flavonoids and synthetic compounds to permeabilize the membrane. This study will be useful for the development of new antibiotic peptides with potent antimicrobial and synergistic activity but without cytotoxicity.

• Journal of Korea Multimedia Society
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• v.22 no.3
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• pp.335-348
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• 2019

Cell segmentation and counting represent one of the most important tasks required in order to provide an exhaustive understanding of biological images. Conventional features suffer the lack of spatial consistency by causing the joining of the cells and, thus, complicating the cell counting task. We propose, in this work, a cascade of networks that take as inputs different versions of the original image. After constructing a Gaussian pyramid representation of the microscopy data, the inputs of different size and spatial resolution are given to a cascade of deep convolutional autoencoders whose task is to reconstruct the segmentation mask. The coarse masks obtained from the different networks are summed up in order to provide the final mask. The principal and main contribution of this work is to propose a novel method for the cell counting. Unlike the majority of the methods that use the obtained segmentation mask as the prior information for counting, we propose to utilize the hidden latent representations, often called the high-level features, as the inputs of a neural network based regressor. While the segmentation part of our method performs as good as the conventional deep learning methods, the proposed cell counting approach outperforms the state-of-the-art methods.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1183-1189
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• 2017

Objective: Owing to the public availability of complete genome sequences, including avian species, massive bioinformatics analyses may be conducted for computational gene prediction and the identification of gene regulatory networks through various informatics tools. However, to evaluate the biofunctional activity of a predicted target gene, in vivo and in vitro functional genomic analyses should be a prerequisite. Methods: Due to a lack of quail genomic sequence information, we first identified the partial genomic structure and sequences of the quail SH3 domain containing ring finger 2 (SH3RF2) gene. Subsequently, SH3RF2 was knocked out using clustered regularly interspaced short palindromic repeat/Cas9 technology and single cell-derived SH3RF2 mutant sublines were established to study the biofunctional activity of SH3RF2 in quail myoblast (QM7) cells during muscle differentiation. Results: Through a T7 endonuclease I assay and genotyping analysis, we established an SH3RF2 knockout (KO) QM7#4 subline with 61 and 155 nucleotide deletion mutations in SH3RF2. After the induction of myotube differentiation, the expression profiles were analyzed and compared between regular QM7 and SH3RF2 KO QM7#4 cells by global RNA sequencing and bioinformatics analysis. Conclusion: We did not detect any statistically significant role of SH3RF2 during myotube differentiation in QM7 myoblast cells. However, additional experiments are necessary to examine the biofunctional activity of SH3RF2 in cell proliferation and muscle growth.

• Food Science of Animal Resources
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• v.31 no.2
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• pp.311-315
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• 2011

The objective of this study was to evaluate the antimicrobial effects of various natural flavonoids against growth of psychotropic Bacillus cereus strains, which cause dairy food outbreaks. Flavonoids were first screened for their ability to inhibit growth of B. cereus strains using the paper-disc diffusion test. Second, the growth inhibitory effect of selected flavonoids was evaluated in tryptic soy broth supplemented with 0.6% yeast extract, and the bactericidal effect of the flavonoids was measured in 0.8% (w/v) NaCl solution. Based on the paper-disc diffusion test, kaempferol was effectively active against B. cereus P14 and B. cereus KCCM 40935. Kaempferol had an antimicrobial effect at concentrations greater than 100 ${\mu}M$, and the numbers of B. cereus P14 and B. cereus KCCM 40935 decreased by 3.55 and 1.5 log cycles, respectively. The cell numbers of B. cereus P14 and B. cereus KCCM 40935 treated with 50 ${\mu}M$ kaempferol were reduced by 4.18 and 2.84 log cycles during a 24 h incubation to test the bactericidal effect of kaempferol (p<0.05). The results indicate that kaempferol had the greatest antimicrobial effect among the psychotropic B. cereus strains and the natural flavonoids tested.

• BMB Reports
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• v.48 no.12
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• pp.691-695
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• 2015

We report that phytosphingosine, a sphingolipid found in many organisms and implicated in cellular signaling, promotes megakaryocytic differentiation of myeloid leukemia cells. Specifically, phytosphingosine induced several hallmark changes associated with megakaryopoiesis from K562 and HEL cells including cell cycle arrest, cell size increase and polyploidization. We also confirmed that cell type specific markers of megakaryocytes, CD41a and CD42b are induced by phytosphingosine. Phospholipids with highly similar structures were unable to induce similar changes, indicating that the activity of phytosphingosine is highly specific. Although phytosphingosine is known to activate p38 mitogen-activated protein kinase (MAPK)-mediated apoptosis, the signaling mechanisms involved in megakaryopoiesis appear to be distinct. In sum, we present another model for dissecting molecular details of megakaryocytic differentiation which in large part remains obscure.

• Journal of Ginseng Research
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• v.47 no.5
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• pp.615-621
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• 2023

Korean Red Ginseng (KRG) plays a key role in heme oxygenase (HO)-1 induction under physical and moderate oxidative stress conditions. The transient and mild induction of HO-1 is beneficial for cell protection, mitochondrial function, regeneration, and intercellular communication. However, chronic HO-1 overexpression is detrimental in severely injured regions. Thus, in a chronic pathological state, diminishing HO-1-mediated ferroptosis is beneficial for a therapeutic approach. The molecular mechanisms by which KRG protects various cell types in the central nervous system have not yet been established, especially in terms of HO-1-mediated mitochondrial functions. Therefore, in this review, we discuss the multiple roles of KRG in the regulation of astrocytic HO-1 under pathophysiological conditions. More specifically, we discuss the role of the KRG-mediated astrocytic HO-1 pathway in regulating mitochondrial functions in acute and chronic neurodegenerative diseases as well as physiological conditions.