• Parasites, Hosts and Diseases
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• v.62 no.1
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• pp.75-84
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• 2024

Ancylostoma ceylanicum is a zoonotic soil-derived nematode that parasitizes the intestines of humans and animals (dogs and cats), leading to malnutrition and iron-deficiency anemia. Helminth parasites secrete calreticulin (CRT), which regulates or blocks the host's immune response. However, no data on A. ceylanicum calreticulin (Ace-CRT) are available. We investigated the biological function of recombinant Ace-CRT (rAce-CRT). rAce-CRT showed reliable antigenicity and stimulated the proliferation of mouse splenocytes and canine peripheral blood mononuclear cells. Quantitative reverse-transcription PCR assays revealed that rAce-CRT primarily promoted the expression of T helper 2 cytokines, particularly IL-13, in canine peripheral blood lymphocytes. rAce-CRT inhibited complement-mediated sheep erythrocyte hemolysis in vitro. Our findings indicate that Ace-CRT plays an immunomodulatory role and may be a promising candidate molecule for a hookworm vaccine.

• Journal of the Korean Chemical Society
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• v.54 no.3
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• pp.291-294
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• 2010

In this study, we demonstrated high-efficiency blue organic light-emitting diodes (OLEDs) employing BCzVBi as a blue fluorescent dye doped into blue host material, DPVBi with various concentration. The optimized blue OLED device having high-efficiency was constructed with structure of NPB (500 ${\AA}$) / DPVBi:BCzVBi-6% (150 ${\AA}$)/$Alq_3$(300 ${\AA}$) / Liq (20 ${\AA}$) / Al (1000 ${\AA}$). The maximum luminescence of blue OLED was 13200 cd/$m^2$ at 13.8 V and current density and maximum efficiency were 26.4 mA/$cm^2$ at 1000 cd/$m^2$ and 4.24 cd/A at 3.9 V, respectively. Luminous efficiency shows two times higher than comparing with non-doped BCzVBi blue OLED whereas $CIE_{x,y}$ coordinate was similar with bare DPVBi blue OLED such as (0.16, 0.19). Electroluminescence of BCzVBi-6% doped blue OLED has two major peaks at 445 nm and 470 nm whereas pure DPVBi's blue peak appears at 456 nm and it is happened through endothermic Forster energy transfer by molecule's vibration between LUMO of DPVBi as host material and LUMO of BCzVBi as dopant in device.

• Parasites, Hosts and Diseases
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• v.29 no.2
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• pp.121-128
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• 1991

The degree of attraction of Toxoplasma gondii to vertebrate cells varies with cell type and cell phase. Human promyelocytic leukemia cells, HL-60, were synchronized by double thymidine block method and co-cultured with Toxoplasma for 1 hr at each cell stage to investigate the cell cycle specific susceptibility of parasites to host cells. For 30 hr the average number of Texoplasma that invaded was a little changed except at 3 hr from G1/S phase boundary which concurred with the peak point of DNA synthesis. At 3 hr which is a relatively short interval compared to whole S phase, modification of cells by parasitic invasion was most remarkable. The number of Toxoplasma that penetrated was increased to more than sin times. The shape of the cells became sludgy and almost indiscernible by strong accessibility of parasites only for an hour of mfd-S phase. The same auctuation was also observed at the second peak of S phase but weakly. This suggests that there be surface molecules concerning with the attachment of Texoplasma to the host cells, which is expressed at special point of S phase. further studies on the specific protein or similar molecules related could be carried out using synchronized HL-60 cells.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.895-902
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• 2002

Monocytes and macrophages playa major role in defense mechanism of the host response to tumor, in part through the secretion of several potent products and macrophage cytokines. Monocytes and tissue macro phages produce at least two groups of protein mediators of inflammation, interleukin 1 (IL-1) and tumor necrosis factor (TNF). Recent studies emphasizes that TNF and IL-1 modulate the inflammatory function of endothelial cells, leukocytes, and fibroblasts. In this study, our work is directed toward studying the in vitro effects of Korean propolis on the ability to induce cellular and secretory responses in murine macrophage cell line, RAW 264.7. It was found that Water Extract of Korean Propolis (WEP) could activate macro phages by producing cytokines. The production of the macrophage cytokines, IL-1 and TNF-$\alpha$, by RAW 264.7 treated with WEP was examined from 2.5 $\mu\textrm{g}$/ml up to 25 $\mu\textrm{g}$/ml with dose dependent manner. Nitric oxide (NO) production was also increased when cells were exposed to combination of LPS and WEP from 2.5 $\mu\textrm{g}$/ml up to 25 $\mu\textrm{g}$/ml. At high dose of WEP (50 to 100 $\mu\textrm{g}$/ml) used to prescribe for anti-inflammatory and analgesic medicine showed inhibition of NO production in LPS-stimulated macrophage. Besides cytokine production, NO release, surface molecule expression and cell morphologic antigen expression were increased in response to the stimulation by WEP. These results suggested WEP may function through macrophage activation.

• Korean Journal of Microbiology
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• v.50 no.2
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• pp.87-94
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• 2014

Nitric oxide (NO), which has been recognized as an integral molecule in maintaining homeostasis, plays an important role in host defense against microbes. NO has diverse antimicrobial mechanisms by directly and/or indirectly interacting with microbes. Under the circumstance that there is an urgent need for a new class of antimicrobial agents due to antibiotic resistance, much effort has been made to develop a NO-based antimicrobial agent. In order to make it possible, strategies to store and release NO in a controlled manner are required because NO has a gaseous property and a very short half-life. In this review, we described NO biochemistry and its mechanisms of antimicrobial activity. In additions, we introduced various NO-releasing systems that improve NO's antimicrobial activity.

• Parasites, Hosts and Diseases
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• v.55 no.4
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• pp.375-384
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• 2017

Trichomonas vaginalis is a pathogen that triggers severe immune responses in hosts. T. vaginalis ${\alpha}$-actinin 2, $Tv{\alpha}$-actinin 2, has been used to diagnose trichomoniasis. This study was undertaken to examine the role of $Tv{\alpha}$-actinin 2 as an antigenic molecule to induce immune responses from humans. Western blot analysis using anti-$Tv{\alpha}$-actinin 2 antibodies indicated its presence in the secreted proteins of T. vaginalis. ELISA was employed to measure cytokine production by vaginal epithelial cells, prostate cells, mouse dendritic cells (DCs), or T cells stimulated with T. vaginalis or $Tv{\alpha}$-actinin 2 protein. Both T. vaginalis and $rTv{\alpha}$-actinin 2 induced cytokine production from epithelial cell lines, including IL-10. Moreover, $CD4^+CD25^-$ regulatory T cells (Treg cells) incubated with $rTv{\alpha}$-actinin 2-treated DCs produced high levels of IL-10. These data indicate that $Tv{\alpha}$-actinin 2 modulates immune responses via IL-10 production by Treg cells.

• Environmental Analysis Health and Toxicology
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• v.15 no.3
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• pp.69-80
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• 2000

ADP-rubosylation may be involved in the process of macrophage activation. Nitric oxide (NO) has emerged as an important intracellular and interacellular regulatory molecule with function as diverse as vasodilation, neural communication or host defense. NO is derived from the oxidation of the terminal guanidino nitrogen atom of L-arginine by the NADPH -dependent enzyme, nitric oxide synthase (NOS) which is one of the three different isomers in mammalian tissues. Since NO can exert protective or regulatory functions in the cell at a low concentration while toxic effects at higher concentrations, its role may be tightly regulated in the cell. Therefore, this paper was focused on signal transduction pathway of NO synthesis, role of endogenous TGF-$\beta$ in NO production. effect of NO on superoxide formation. Costimulation of murine peritoneal macrophages with interferon-gamma (IFN-γ) and phorbol 12-myristate 13-acetate (PMA) increased both NO secretion and mRNA expression of inducible nitric oxide synthase (iNOS) when PMA abolished costimulation. Pretreatmnet of the cells with PMA abolished costimuation effects due to the depletion of protein kinase C (PKC) activities . The involvement of PKC in NO secretion could be further confirmed by PKC inhibitor, stauroprine, and phorbol ester derivative, phorbol 12,13-didecanoate. Addition of actinomycine D in IFN-γ plus PMA stimulated cells inhibited both NO secretion and mRNA expression of iNOS indication that PMA stabilizes mRNA of iNOS . Exogenous TGF-$\beta$ reduced NO secretion in IFN -γ stimulated murine macrophages. However addition of antisense oligodeoxynucleotide (ODN) to TGF-$\beta$ to this system recovered the ability of NO production and inhibited mRNA expression of TGF-$\beta$. ACAS interactive laser cytometry analysis showed that transportation of FITC -labeled antisense ODN complementary to TGF-$\beta$ mRNA could be observed within 5 min and reached maximal intensity in 30 min in the murine macrophage cells. NO released by activated macrophages inhibits superoxide formation in the same cells . This inhibition nay be related on NO-induced auto -adenosine diphosphate (ADP) -ribosylation . In addition, ADP-ribosylation may be involved in the process of macrophage activation .

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.596-602
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• 2016

Staphylococcus aureus, like other gram-positive pathogens, has evolved a large repertoire of virulence factors as a powerful weapon to subvert the host immune system, among which alpha-hemolysin (Hla), a secreted pore-forming cytotoxin, plays a preeminent role. We observed a concentration-dependent reduction in Hla production by S. aureus in the presence of sub-inhibitory concentrations of isorhamnetin, a flavonoid from the fruits of Hippophae rhamnoides L., which has little antibacterial activity. We further evaluate the effect of isorhamnetin on the transcription of the Hla-encoding gene hla and RNAIII, an effector molecule in the agr system. Isorhamnetin significantly down-regulated RNAIII expression and subsequently inhibited hla transcription. In a co-culture of S. aureus and lung cells, topical isorhamnetin treatment protected against S. aureus-induced cell injury. Isorhamnetin may represent a leading compound for the development of anti-virulence drugs against S. aureus infections.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.155-162
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• 2002

Cytochrome P45O (CYP) gene has been known to play one of the most important roles in metabolizing the exogenous materials. In insect, CYP is particularly known to detoxify toxic materials by adding oxygen molecule to the hydrophobic region of the materials. Thus, CYP-dependent metabolism is associated with the adaptation of insect to host plant chemicals. This in turn is known to be one of the driving forces for CYP diversification. In the present study, we cloned seven gene fragments of CYP 4 (CYP4) family from the midgut of the beet armyworm, Spodoptera exigua, through RT.PCT, Sequence analysis of the product showed the gene fragment to contain an open reading frame of ~150 amino acids, consisted of ~450 bp. The cloned gene fragments contained typical, conserved regions found in CYP4 family. Pairwise comparison of the deduced amino acid sequences among seven clones ranged in divergence from 0% to 52.86% and resulted in five distinct clones. The other two clones were identical or differ by one amino acid respectively to the corresponding clone, although each differed by ten nucleotides. Analysis of correlation between GenBank-registered, full length CYP4 and the cloned fragments resulted in statistically significant relationship ($r^{2}$ = 0.96085; p < 0.001), suggesting utility of the partial sequences as such full-length sequences. Phylogenetic analysis of the clones with GenBank-registered insect and mammal CYP4 family sequences by parsimony and several distance methods subdivided the clones into two groups: tones belonging to CYP4S and the others to CYP4M families.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.543-551
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• 2002

Nitric oxide (NO) is a small molecule (mol. wt. 30 Da) and oxidative free radical. It is uncharged and can therefore diffuse freely within and between cells across membrane. Such characteristics make it a biologically important messenger in physiologic processes such as neurotransmission and the control of vascular tone. NO is also highly toxic and is known to acts as a mediator of cytotoxicity during host defense. NO is synthesized by nitric oxide synthase (NOS) through L-arginine/nitric oxide pathway which is a dioxygenation process. NO synthesis involves several participants, three co-substrates, five electrons, five co-factors and two prosthetic groups. Under normal condition, low levels of NO are synthesized by type I and III NOS for a short period of time and mediates many physiologic processes. Under condition of oxidant stress, high levels of NO are synthesized by type II NOS and inhibits a variety of metabolic processes and can also cause direct damage to DNA. Such interaction result in cytostasis, energy depletion and ultimately cell death. NO has the potential to interact with a variety of intercellular targets producing diverse array of metabolic effects. It is known that NO is involved in hemodynamic regulation, neurogenic inflammation, re-innervation, management of dentin hypersensitivity on teeth. Under basal condition of pulpal blood flow, NO provides constant vasodilator tone acting against sympathetic vasoconstriction. Substance P, a well known vasodilator, was reported to be mediated partly by NO, while calcitonin-gene related peptide has provided no evidence of its relation with NO. This review describes the roles of NO in dental pulp in addition to the known general roles of it.