• Proceedings of the Botanical Society of Korea Conference
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• 2002.04a
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• pp.62-72
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• 2002

This study has investigated the biosynthesis and function of the heavy metal binding peptides, the phytochelatins, in plants. PCs are synthesised enzymatically from glutathione by the enzyme PC synthase in the presence of heavy metal ions. Using Arabidopsis thaliana as a model organism cadmium-sensitive, phytochelatin-deficient mutants have been isolated and characterised in previous studies. The cadl mutants have wildtype levels of glutathione, are PC deficient and lack PC synthase activity. Thus, the CADl gene has been proposed to encode PC synthase. The CADl gene was isolated by a positional cloning strategy The gene was mapped and a candidate identified. Each of four cadl mutants had a single base pair change in the candidate gene and the cadmium-sensitive, cadl phenotype was complemented by the candidate gene. This demonstrated the CADl gene had been cloned. A homologous gene in the fission yeast, Schizosaccharomyces pombe was identified through database searches. A targeted-deletion mutation of this gene was constructed and the mutant, like cadl mutants of Arabidopsis, was cadmium-sensitive and PC-deficient. A comparison of the redicted amino acid sequences reveals a highly conserved N-terminal region Presumed to be the catalytic domain and a variable C-terminal region containing multiple Cys residues proposed to be involved in activation of the enzyme by metal ions. Similar genes were also identified in animal species. The Arabidopsis CADl/AtPCSl and S. pombe SpbPCS genes were expressed in E. coli and were shown to be sufficient for glutathione-dependent, heavy metal activate PC synthesis in vitro, thus demonstrating these genes encode PC synthase enzymes. Using RT-PCR, AtPCSl expression appeared to be independent of Cd exposure. However, at higher levels of Cd exposure a AtPCSl-CUS reporter gene construct appeared to be more highly expressed. Using the reporter gene construct, AtPCSl was expressed most tissues. Expression appeared to be greater in younger tissues and same higher levels of expression was observed in some regions, including carpels and the base of siliques. AtPCS2 was a functional gene encoding an active PC synthase. However, its Pattern of expression and the phenotype of a mutant (or antisense line) have not been determined. Assuming the gene is functional then it has clearly been maintained through evolution and must provide some selective advantage. This implies that, at least in some cells or tissue, it is likely to be the dominant PC synthase expressed. This remains to be determined

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.6
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• pp.695-702
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• 2017

The sustained tonic currents ($I_{tonic}$) generated by ${\gamma}$-aminobutyric acid A receptors ($GABA_{A}Rs$) are implicated in diverse age-dependent brain functions. While various mechanisms regulating $I_{tonic}$ in the hippocampus are known, their combined role in $I_{tonic}$ regulation is not well understood in different age groups. In this study, we demonstrated that a developmental increase in GABA transporter (GAT) expression, combined with gradual decrease in $GABA_AR{\alpha}_5$ subunit, resulted in various $I_{tonic}$ in the dentate gyrus granule cells (DGGCs) of preadolescent rats. Both GAT-1 and GAT-3 expression gradually increased at infantile ($P_{6-8}$ and $P_{13-15}$) and juvenile ($P_{20-22}$ and $P_{27-29}$) stages, with stabilization observed thereafter in adolescents ($P_{34-36}$) and young adults ($P_{41-43}$). $I_{tonic}$ facilitation of a selective GAT-1 blocker (NO-711) was significantly less at $P_{6-8}$ than after $P_{13-15}$. The facilitation of $I_{tonic}$ by SNAP-5114, a GAT-3 inhibitor, was negligible in the absence of exogenous GABA at all tested ages. In contrast, $I_{tonic}$ in the presence of a nonselective GAT blocker (nipecotic acid, NPA) gradually decreased with age during the preadolescent period, which was mimicked by $I_{tonic}$ changes in the presence of exogenous GABA. $I_{tonic}$ sensitivity to L-655,708, a $GABA_AR{\alpha}_5$ subunit inverse agonist, gradually decreased during the preadolescent period in the presence of NPA or exogenous GABA. Finally, Western blot analysis showed that the expression of the $GABA_AR{\alpha}_5$ subunit in the dentate gyrus gradually decreased with age. Collectively, our results suggested that the $I_{tonic}$ regulation of altered GATs is under the final tune of $GABA_AR{\alpha}_5$ subunit activation in DGGCs at different ages.

• The Korean Journal of Physiology
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• v.29 no.1
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• pp.13-27
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• 1995

single $K^{+}$ channels of skeletal muscle from the rat and frog were into planar lipid bilayers and their properties were studied. Fusion was induced by an osmotic gradient. Of the four types of $K^{+}$ channels recorded, the two most frequently observed were a voltage and $Ca^{2+}-activated$ $K^{+}$ channel and a $K^{+}$ channel with a prominent conductance substate. The first $K^{+}$ channel was identified as the large $Ca^{2+}-activated$ $K^{+}$ (BK) channel because the open-state probability was increased with depolarization (e-fold change per $10.6{\pm}3.5$ mV, n=8) and internal $Ca^{2+}$ (half-activation at $16.7{\pm}3.8$ mV, n=8, pCa 4) and its conductance was large ($247{\pm}4.9$ pS, n=24 in 0.1 M KCI). Lifetime distributions of open- and closed-states could be fitted with single exponentials of several milliseconds. The mean open- and closed-lifetimes were linearly dependent on the intracellular $[Ca^{2+}]$ and $1/[Ca^{2+}]$, respectively. The second $K^{+}$ channel showed a conductance substate at $30{\sim}60%$ of the open state. Its current-voltage relation was linear in the range of $-80\;{\sim}\;+80\;mV$. The slope conductance of the substate and open-state were 40 and 144 pS in 0.2 M KCl, respectively. The channel was highly selective for $K^{+}$ over Cl. The open-state probability was weakly voltage-dependent (e-fold change per 35 mV. The lifetime distributions of open- and closed-states were fitted with two exponentials and the major gating occurred slowly at several hundred milliseconds. Based on the above results, we think the second type of $K^{+}$ channel is the sarcoplasmic reticulum $K^{+}$ (SRK) channel. In addition, both types of channel were also incorporated into the lipids extracted from the skeletal muscle. The channel properties recorded in the bilayers termed from synthetic and extracted lipids were qualitatively similar. Our data indicate that BK and SRK channels are rich in the skeletal muscle and their properties and regulation could be effectively studied in planar lipid bilayer.

• Clinical and Experimental Emergency Medicine
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• v.3 no.3
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• pp.175-180
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• 2016

Objective Combination of ${\beta}_1-adrenergic$ receptor (AR) blockade and ${\beta}_2-AR$ activation might be a potential novel therapy for treating heart failure. However, use of ${\beta}-AR$ agonists and/or antagonists in the clinical setting is controversial because of the lack of information on cardiac inotropic or chronotropic regulation by AR signaling. Methods In this study, we performed hemodynamic evaluation by examining force frequency response (FFR), Frank-Starling relationship, and response to a non-selective ${\beta}-AR$ agonist (isoproterenol) in hearts isolated from 6-month-old transgenic (TG) mice overexpressing ${\beta}_1-$ and ${\beta}_2-ARs$ (${\beta}_1-$ and ${\beta}_2-AR$ TG mice, respectively). Results Cardiac physiologic consequences of ${\beta}_1-$ and ${\beta}_2-AR$ overexpression resulted in similar maximal response to isoproterenol and faster temporary decline of positive inotropic response in ${\beta}_2-AR$ TG mice. ${\beta}_1-AR$ TG mice showed a pronounced negative limb of FFR, whereas ${\beta}_2-AR$ TG mice showed high stimulation frequencies with low contractile depression during FFR. In contrast, Frank-Starling relationship was equally enhanced in both ${\beta}_1-$ and ${\beta}_2-AR$ TG mice. Conclusion Hemodynamic evaluation performed in the present showed a difference in ${\beta}_1-$ and ${\beta}_2-AR$ signaling, which may be due to the difference in the desensitization of ${\beta}_1-$ and ${\beta}_2-ARs$.

• The Korean Journal of Pain
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• v.34 no.1
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• pp.27-34
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• 2021

Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a major reason for stopping or changing anticancer therapy. Among the proposed pathomechanisms underlying CIPN, proinflammatory processes have attracted increasing attention. Here we assessed the role of prostaglandin D2 (PGD2) signaling in cisplatin-induced neuropathic pain. Methods: CIPN was induced by intraperitoneal administration of cisplatin 2 mg/kg for 4 consecutive days using adult male Sprague-Dawley rats. PGD2 receptor DP1 and/or DP2 antagonists were administered intrathecally and the paw withdrawal thresholds were measured using von Frey filaments. Spinal expression of DP1, DP2, hematopoietic PGD synthase (H-PGDS), and lipocalin PGD synthase (L-PGDS) proteins were analyzed by western blotting. Results: The DP1 and DP2 antagonist AMG 853 and the selective DP2 antagonist CAY10471, but not the DP1 antagonist MK0524, significantly increased the paw withdrawal threshold compared to vehicle controls (P = 0.004 and P < 0.001, respectively). Western blotting analyses revealed comparable protein expression levels in DP1 and DP2 in the spinal cord. In the CIPN group the protein expression level of L-PGDS, but not of H-PGDS, was significantly increased compared to the control group (P < 0.001). Conclusions: The findings presented here indicate that enhanced PGD2 signaling, via upregulation of L-PGDS in the spinal cord, contributes to mechanical allodynia via DP2 receptors in a cisplatin-induced neuropathic pain model in rats, and that a blockade of DP2 receptor activation may present a novel therapeutic target for managing CIPN.

• Journal of Surface Science and Engineering
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• v.54 no.1
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• pp.1-11
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• 2021

Porous dendrite structure AuCu alloy was formed using a hydrogen bubble template (HBT) technique by electroplating to improve the catalytic performance of gold, known as an excellent oxygen reduction reaction (ORR) catalyst in alkaline medium. The rich Au surface was maximized by selectively electrochemical etching Cu on the AuCu dendrite surface well formed in a leaf shape. The catalytic activity is mainly due to the synergistic effect of Au and Cu existing on the surface and inside of the particle. Au helps desorption of OH- and Cu contributes to the activation of O2 molecule. Therefore, the porous AuCu dendrite alloy catalyst showed markedly improved catalytic activity compared to the monometallic system. The porous structure AuCu formed by the hydrogen bubble template was able to control the size of the pores according to the formation time and applied current. In addition, the Au-rich surface area increased by selectively removing Cu through electrochemical etching was measured using an electrochemical calculation method (ECSA). The results of this study suggest that the alloying of porous AuCu dendrites and selective Cu dissolution treatment induces an internal alloying effect and a large specific surface area to improve catalyst performance.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.259-271
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• 2021

Many bacteria metabolize aromatic compounds via catechol as a catabolic intermediate, and possess multiple genes or clusters encoding catechol-cleavage enzymes. The presence of multiple isozyme-encoding genes is a widespread phenomenon that seems to give the carrying strains a selective advantage in the natural environment over those with only a single copy. In the naphthalene-degrading strain Pseudomonas putida ND6, catechol can be converted into intermediates of the tricarboxylic acid cycle via either the ortho- or meta-cleavage pathways. In this study, we demonstrated that the catechol ortho-cleavage pathway genes (catBICIAI and catBIICIIAII) on the chromosome play an important role. The catI and catII operons are co-transcribed, whereas catAI and catAII are under independent transcriptional regulation. We examined the binding of regulatory proteins to promoters. In the presence of cis-cis-muconate, a well-studied inducer of the cat gene cluster, CatRI and CatRII occupy an additional downstream site, designated as the activation binding site. Notably, CatRI binds to both the catI and catII promoters with high affinity, while CatRII binds weakly. This is likely caused by a T to G mutation in the G/T-N11-A motif. Specifically, we found that CatRI and CatRII regulate catBICIAI and catBIICIIAII in a cooperative manner, which provides new insights into naphthalene degradation.

• Biomolecules & Therapeutics
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• v.29 no.5
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• pp.551-561
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• 2021

Thyroid cancer is the most common endocrine malignancy. Patients with well-differentiated thyroid cancers, such as papillary and follicular cancers, have a favorable prognosis. However, poorly differentiated thyroid cancers, such as medullary, squamous and anaplastic advanced thyroid cancers, are very aggressive and insensitive to radioiodine treatment. Thus, novel therapies that attenuate metastasis are urgently needed. We found that both PDGFC and PDGFRA are predominantly expressed in thyroid cancers and that the survival rate is significantly lower in patients with high PDGFRA expression. This finding indicates the important role of PDGF/PDGFR signaling in thyroid cancer development. Next, we established a SW579 squamous thyroid cancer cell line with 95.6% PDGFRA gene insertion and deletions (indels) through CRISPR/Cas9. Protein and invasion analysis showed a dramatic loss in EMT marker expression and metastatic ability. Furthermore, xenograft tumors derived from PDGFRA geneedited SW579 cells exhibited a minor decrease in tumor growth. However, distant lung metastasis was completely abolished upon PDGFRA gene editing, implying that PDGFRA could be an effective target to inhibit distant metastasis in advanced thyroid cancers. To translate this finding to the clinic, we used the most relevant multikinase inhibitor, imatinib, to inhibit PDGFRA signaling. The results showed that imatinib significantly suppressed cell growth, induced cell cycle arrest and cell death in SW579 cells. Our developed noninvasive apoptosis detection sensor (NIADS) indicated that imatinib induced cell apoptosis through caspase-3 activation. In conclusion, we believe that developing a specific and selective targeted therapy for PDGFRA would effectively suppress PDGFRA-mediated cancer aggressiveness in advanced thyroid cancers.

• The Korea Journal of Herbology
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• v.36 no.6
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• pp.1-8
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• 2021

Objectives : Atractylodis rhizoma Alba has been traditionally used as a medicinal resource that is used for enhancing Qi (氣) in traditional medicine in Korea, China, and Japan. This study investigated the protective effects of Atractylodis rhizoma Alba extract (ARE) against trimethyltin (TMT), a neurotoxin that causes selective hippocampal injury, using both in vitro and in vivo models. Methods : We investigated the effects of ARE on TMT- (5mM) induced cytotoxicity in primary cultures of mouse hippocampal cells (7 days in vitro ) and on hippocampal injury in C57BL/6 mice injected with TMT (2.6 mg/kg). Results : We observed that ARE treatment (0 - 50 ㎍/mL) significantly reduced TMT-induced cytotoxicity in cultured hippocampal neurons in a dose-dependent manner, based on results of lactate dehydrogenase and 3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assays. Additionally, this study showed that orally administered ARE (5 mg/kg; between -6 and 0 days before TMT injection) significantly attenuated seizures in adult mice. Furthermore, quantitative analysis of allograft inflammatory factor-1 (Iba-1)- and glial fibrillary acidic protein (GFAP)- positive cells showed significantly reduced levels of Iba-1- and GFAP-positive cell bodies in the dentate gyrus of mice treated with ARE prior to TMT injection. These findings indicate the significant protective effects of ARE against the TMT-induced massive activation of microglia and astrocytes in the hippocampus. Conclusions : We conclude that ARE minimizes the detrimental effects of TMT-induced hippocampal neurotoxicity, both in vitro and in vivo . Our findings may serve as useful guidelines to support ARE administration as a promising pharmacotherapeutic approach to hippocampal degeneration.

• Korean Journal of Forensic Psychology
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• v.11 no.3
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• pp.329-347
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• 2020

When a person suggests an estimate under uncertainty, (s)he tend to rely on the information and number provided in advance. As a result, their final estimate would be assimilated to the initial value. This phenomenon is called "anchoring effect". The present research examined anchoring effects observed in law courts. Sentencing decision of jurors can be influenced by the sentence demanded by the prosecutor. Specifically, this study demonstrated the condition in which anchoring effect would be stronger and practical solutions for lowering anchoring effect. Study 1 demonstrated whether gravity of criminal cases and levels of anchor influenced anchoring effects. As expected, anchoring effect was stronger in a heavier criminal case than in a lighter one. When a low anchor was provided in a lighter case, anchoring effect was stronger compared to when a high anchor was provided. Study 2 examined how emotion affects anchoring effects. The results showed that anchoring effect appeared to be significantly stronger with feelings of anger than of sadness. Study 3 examined the solution for reducing anchoring effects in a court. When activation of selective-accessibility model was prevented, anchoring effects significantly decreased. These results can help solve the problems about juror judgmental bias and contribute to the development of Korean jury trial.