• BMB Reports
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• v.36 no.3
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• pp.282-287
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• 2003

The production of superoxide dismutase (SOD) varied in Deinococcus radiophilus, the UV resistant bacterium, depending upon different phases of growth, UV irradiation, and superoxide treatment. A gradual increase in total SOD activity occurred up to the stationary phases. The electrophoretic resolution of the SOD in cell extracts of D. radiophilus at each growth phase revealed the occurrence of MnSOD throughout the growth phases. The SOD profiles of D. radiophilus at the exponential phase received oxidative stress by the potassium superoxide treatment or UV irradiation also revealed the occurrence of a single SOD. However, these treatments caused an increase in SOD activity. The data strongly suggest that D. radiophilus has only one species of SOD as a constitutive enzyme, which seems to be a membrane-associated protein.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.3
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• pp.114-119
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• 2013

Potassium is essential for the proper functioning of the ears. The inner ear's endolymph differs from all other extracellular fluids (in its positive potential) and in the ionic compositions in the various parts of the endolymphatic space. Ion concentration of the endolymph is 150 mM of potassium, which is comparable to the concentrations in other organs. Cisplatin (cis-diamminedichloroplatinum II: CDDP) is one of the most effective anticancer drugs, widely used against various tumors. However, its clinical use is limited by the onset of severe side effects, including ototoxicity and nephrotoxicity. For ototoxicity, a number of evidences in cytotoxic mechanism of cisplatin, including perturbation of redox status, increase in lipid peroxydation, and formation of DNA adduct, have been suggested. Therefore, in this study, the author investigated the relationship between the potassium ions on cisplatin-induced cytotoxicity in HEI-OC1 cells associated with reactive oxygen species (ROS). KCNE1 gene expression by the concentration of intracellular potassium appeared in the plasma membrane and increased the concentration of intracellular potassium. Cisplatin decreased the viability of HEI-OC1 cells, but the KCNE1 gene increased. Also, the KCNE1 gene significantly suppressed generation of intracellular ROS by cisplatin. Western blot analysis showed that the KCNE1 gene increased phase II detoxification enzymes markers such as superoxide dismutase 1 (SOD1), superoxide dismutase (SOD2), NAD(P)H:quinine oxidoreductases (NQO1), which were associated with the scavenger of ROS. These results suggest that the KCNE1 gene for intracellular potassium concentration ultimately prevents ROS generation from cisplatin and further contributes to protect auditory sensory hair cells from ROS produced by cisplatin.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.4
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• pp.371-376
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• 2017

The caudal subnucleus of the spinal trigeminal nucleus (medullary dorsal horn; MDH) receives direct inputs from small diameter primary afferent fibers that predominantly transmit nociceptive information in the orofacial region. Recent studies indicate that reactive oxygen species (ROS) is involved in persistent pain, primarily through spinal mechanisms. In this study, we aimed to investigate the role of xanthine/xanthine oxidase (X/XO) system, a known generator of superoxide anion ($O_2{^-}$), on membrane excitability in the rat MDH neurons. For this, we used patch clamp recording and confocal imaging. An application of X/XO ($300{\mu}M/30mU$) induced membrane depolarization and inward currents. When slices were pretreated with ROS scavengers, such as phenyl N-tert-butylnitrone (PBN), superoxide dismutase (SOD), and catalase, X/XO-induced responses decreased. Fluorescence intensity in the DCF-DA and DHE-loaded MDH cells increased on the application of X/XO. An anion channel blocker, 4,4-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS), significantly decreased X/XO-induced depolarization. X/XO elicited an inward current associated with a linear current-voltage relationship that reversed near -40 mV. X/XO-induced depolarization reduced in the presence of $La^{3+}$, a nonselective cation channel (NSCC) blocker, and by lowering the external sodium concentration, indicating that membrane depolarization and inward current are induced by influx of $Na^+$ ions. In conclusion, X/XO-induced ROS modulate the membrane excitability of MDH neurons, which was related to the activation of NSCC.

• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.803-809
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• 2009

Recent evidence has revealed the occurrence of an apoptotic phenotype in Candida albicans that is inducible with environmental stresses such as acetic acid, hydrogen peroxide, and amphotericin B. In the present study, we found that the Chinese herbal medicine Baicalein (BE), which was one of the skullcapflavones, can induce apoptosis in C. albicans. The apoptotic effects of BE were detected by flow cytometry using Annexin V-FITC and DAPI, and it was confirmed by transmission electron microscopy analysis. After exposure to 4 ${\mu}g$/ml BE for 12 h, about 10% of C. albicans cells were apoptotic. Both the increasing intracellular levels of reactive oxygen species (ROS) and upregulation of some redox-related genes (CAP1, SOD2, TRR1) were observed. Furthermore, we compared the survivals of CAP1 deleted, wild-type, and overexpressed strains and found that Cap1p attenuated BE-initiated cell death, which was coherent with a higher mRNA level of the CAP1 gene. In addition, the mitochondrial membrane potential of C. albicans cells changed significantly (p<0.001) upon BE treatment compared with control. Taken together, our results indicated that BE treatment induced apoptosis in C. albicans cells, and the apoptosis was associated with the breakdown of mitochondrial membrane potential.

• Journal of Korean Medicine Rehabilitation
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• v.34 no.2
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• pp.15-28
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• 2024

Objectives We used the D-galactose (D-gal) induced C2C12 myoblast senescence model to investigate whether ethanol extract of Perilla. fructescens leaves (EEPF) could delay cellular senescence and regulate related mechanisms. Methods C2C12 myogenic cells were cultured in an incubator under 37 ℃ and 5% CO₂ conditions. EEPF, dried perilla leaves were pulverized and extracted at 1:10 (v/v) at 50 ℃ for 4 hours. Cell counting kit-8 and western blot analysis was performed. Annexin V-FITC apoptosis detection kit and DAPI staining was applied. Catalase (CAT), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and malondialdehyde analysis kits were used. To measure the level of reactive oxygen species generation, staining and flow cytometry was used. To analyze the mitochondrial activity, membrane potential changes were measured using JC-1. 𝛽-gal activity was analyzed using SA-𝛽-gal staining solution, and DNA damage was analyzed by using 𝛾-H2AX. Quantikine ELISA kit was used to analyze inflammatory cytokine production. Results According to the results of this study, EEPF significantly alleviated the decrease in cell viability in C2C12 cells treated with D-gal and suppressed the decrease in the expression of proliferating cell nuclear antigen. EEPF also markedly blocked D-gal-induced C2C12 cell apoptosis and restored reduced activity of CAT, GSH-Px, T-AOC, SOD. In addition, EEPF suppressed the decrease in 𝛽-galactosidase activity, the induction of DNA damage and the increase in expression of senescence-associated secretory phenotype proteins such as p16, p53 and p21 in D-gal-treated C2C12 cells. Furthermore, EEPF significantly attenuated D-gal-induced production and expression of inflammatory cytokines such as interleukin (IL)-6 and IL-18. Conclusions The results of this study indicate that EEPF can be used as a potential candidate for the prevention and treatment of muscle aging.

• Journal of Korean Society of Forest Science
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• v.99 no.2
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• pp.244-250
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• 2010

The aim of this study was to investigate relationship among seed viability and enzymes activities involved in scavenging reactive oxygen species (ROS), especially, superoxide dismutase (SOD), glutathione reductase (GR), and catalase (CAT). In other respects, osmopriming has been demonstrated to reinvigorate aged seeds. Various viabilities of seeds that were ranged from 80 to 100% of germination rate could be produced using osmopriming and accelerated aging treatments. Priming treatment of Pinus thunbergii seeds for 3 days at $15^{\circ}C$ with a polyethylene glycol solution at -1.2 MPa improved their subsequent germination at $25^{\circ}C$. Accelerated aging (3, 6, 9, and 12 days at $41^{\circ}C$ and 100% relative humidity) decreased seed germination percentage depending on aging treatment duration. Electrolyte conductivities of seeds were measured as assay of membrane integrity. The conductivity from electrolyte leakage of P. thunbergii seed was also correlated with seed germinability. Conductivity for control seeds that had 95% of germination percentage was 3.48 ${\mu}S\;g^{-1}$, but jumped as doubled (7.98 ${\mu}S\;g^{-1}$) in 12-day-aged seed that had 80% of germination percentage. Our results demonstrate that aging of P. thunbergii seeds is associated with changes in the electrolyte leakage, lipid peroxidation, and antioxidant defense system. Priming of aged seeds progressively restored the initial germinative ability and resulted in a marked decrease in the levels of MDA and conductivity of seed leachate. These effects of priming were also well recovered of GR and CAT activities in aged seed. The improved seed quality by priming treatment appears at least partly attributable to reduced lipid peroxidation, resulting from enhanced antioxidative enzyme activities that are suggesting the antioxidant defense systems play a key role in seed vigor.

• BMB Reports
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• v.55 no.7
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• pp.354-359
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• 2022

MitoNEET, a mitochondrial outer membrane protein containing the Asn-Glu-Glu-Thr (NEET) sequence, controls the formation of intermitochondrial junctions and confers autophagy resistance. Moreover, mitoNEET as a mitochondrial substrate undergoes ubiquitination by activated Parkin during the initiation of mitophagy. Therefore, mitoNEET is linked to the regulation of autophagy and mitophagy. Mitophagy is the selective removal of the damaged or unnecessary mitochondria, which is crucial to sustaining mitochondrial quality control. In numerous human diseases, the accumulation of damaged mitochondria by impaired mitophagy has been observed. However, the therapeutic strategy targeting of mitoNEET as a mitophagy-enhancing mediator requires further research. Herein, we confirmed that mitophagy is indeed activated by mitoNEET inhibition. CCCP (carbonyl cyanide m-chlorophenyl hydrazone), which leads to mitochondrial depolarization, induces mitochondrial dysfunction and superoxide production. This, in turn, contributes to the induction of mitophagy; mitoNEET protein levels were initially increased before an increase in LC3-II protein following CCCP treatment. Pharmacological inhibition of mitoNEET using mitoNEET Ligand-1 (NL-1) promoted accumulation of Pink1 and Parkin, which are mitophagy-associated proteins, and activation of mitochondria-lysosome crosstalk, in comparison to CCCP alone. Inhibition of mitoNEET using NL-1, or mitoNEET shRNA transfected into RAW264.7 cells, abrogated CCCP-induced ROS and mitochondrial cell death; additionally, it activated the expression of PGC-1α and SOD2, regulators of oxidative metabolism. In particular, the increase in PGC-1α, which is a major regulator of mitochondrial biogenesis, promotes mitochondrial quality control. These results indicated that mitoNEET is a potential therapeutic target in numerous human diseases to enhance mitophagy and protect cells by maintaining a network of healthy mitochondria.