• 한국식품조리과학회지
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• 제26권6호
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• pp.848-852
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• 2010

This study investigated the antibacterial activities of extracts and fractions of Sasa borealis against eight bacteria (Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, Psedomonas aerginosa, Salmonella choleraesuis, Serratia marcescens and Vibrio vulnificus) by broth dilution assay. Using survival curves, the kinetics of bacterial inactivation upon exposure to the extracts and fractions were followed for 24 h. In this same manner, MIC (minimum inhibitory concentration) values were determined by broth microdilution assay and then confirmed to be the extract concentrations that inhibited bacterial growth. Sasa borealis extracts showed antibacterial activities against all tested bacteria. In particular, all tested fractions of Sasa borealis had stronger activities than 70% ethanol extract. MIC of Sasa borealis extract was determined to be 5 mg/mL against Salmonella choleraesuis. All fractions of Sasa borealis extract had extremely strong antibacterial activities. MIC of fractions were determined to be 0.03~2.5 mg/mL. These results suggest that the extracts and fractions of Sasa borealis effectively inhibited bacterial growth and thus are useful as natural antibacterial agents.

• BMB Reports
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• 제35권2호
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• pp.220-227
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• 2002

Two aspartate aminoransferase (EC 2.6.1.1) isoenzymes (AAT-1 and AAT-2) from Lupinus albus L. cv Estoril were separated, purified, and characterized. The molecular weight, pI value, optimum pH, optimum temperature, and thermodynamic parameters for thermal inactivation of both isoenzymes were obtained. Studies of the kinetic mechanism, and the kinetics of product inhibition and high substrate concentration inhibition, were performed. The effect of some divalent ions and irreversible inhibitors on both AAT isoenzymes was also studied. Native PAGE showed a higher molecular weight for AAT-2 compared with AAT-1. AAT-1 appears to be more anionic than AAT-2, which was suggested by the anion exchange chromatography. SDS-PAGE showed a similar sub-unit molecular weight for both isoenzymes. The optimum pH (between 8,0 and 9.0) and temperature ($60-65^{\circ}C$) were similar for both isoenzymes. In the temperature range of $45-65^{\circ}C$, AAT-2 has higher thermostability than AAT-1. Both isoenzymes showed a high affinity for keto-acid substrates, as well as a higher affinity to aspartate than glutamate. Manganese ions induced an increase in both AAT isoenzymes activities, but no cooperative effect was detected. Among the inhibitors tested, hydroxylamine affected both isoenzymes activity by an irreversible inhibition mechanism.

• 상하수도학회지
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• 제35권6호
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• pp.489-496
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• 2021

Water disinfection using UV-LED(Light emitting diode) has many advantages, such as smaller footprint and power consumption as well as relatively longer lifespan than those of conventional mercury-UV lamps. Moreover, UV-LED disinfection is considered an environmentally benign process due to its mercury-free nature. In this study, disinfection using an LED module emitting 275nm UV was carried out. 384 UV-LEDs were put into a cylinder tube with a capacity of 1.7 liters. The UV intensity of the UV-LED module was controlled from 1.7 to 8.4 mW/cm². The disinfection efficiency for the model microorganism solutions(E. coli ) was monitored. As the UV intensity(I) and contact time(t) varied, inactivation of the microorganisms from 2 to 4-log-removals(i.e., 99 to 99.99% of disinfection efficiency) was achieved. Disinfection using UV-LED was followed to 1^st order reaction and the reaction rate constant, k was determined. In addition, the relationship between UV intensity(I) and contact time(t) in order to obtain 99.99% of disinfection efficiency was modeled: I^1.2·t= 460, which indicates that the product of UV intensity and contact time requiring 4-log-removals is always constant.

• The Korean Journal of Physiology and Pharmacology
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• 제27권1호
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• pp.95-103
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• 2023

Rosiglitazone is a thiazolidinedione-class antidiabetic drug that reduces blood glucose and glycated hemoglobin levels. We here investigated the interaction of rosiglitazone with Kv3.1 expressed in Chinese hamster ovary cells using the wholecell patch-clamp technique. Rosiglitazone rapidly and reversibly inhibited Kv3.1 currents in a concentration-dependent manner (IC₅₀ = 29.8 µM) and accelerated the decay of Kv3.1 currents without modifying the activation kinetics. The rosiglitazonemediated inhibition of Kv3.1 channels increased steeply in a sigmoidal pattern over the voltage range of -20 to +30 mV, whereas it was voltage-independent in the voltage range above +30 mV, where the channels were fully activated. The deactivation of Kv3.1 current, measured along with tail currents, was also slowed by the drug. In addition, the steady-state inactivation curve of Kv3.1 by rosiglitazone shifts to a negative potential without significant change in the slope value. All the results with the use dependence of the rosiglitazone-mediated blockade suggest that rosiglitazone acts on Kv3.1 channels as an open channel blocker.

• The Korean Journal of Physiology
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• 제26권2호
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• pp.113-122
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• 1992

It is well known that chromaffin cells of adrenal medulla secrete catecholamine in response to sympathetic nerve activation and the influx of $Ca^{2+}$ through the voltage dependent $Ca^{2+}$ channels (VDCC) in the cell membrane do a major role in this secretory process. In this study, we explored the effect of divalent cations on VDCC of rat chromaffin cells. Rat (Sprague-Dawley rat, 150-250 gm) chromaffin cells were isolated and cultured. Standard giga seal, whole cell recording techniques were employed to study $Ca^{2+}$ current with external and internal solutions that could effectively isolate VDCC currents $(NMG\;in\;external\;and\;TEA\;and\;Cs^{2+}\;in\;internal\;solution)$. The voltage dependence and the inactivation time course of VDCC in our cells were identical to those of bovine chromaffin cells. A persistent inward current was first activated by depolarizing step pulse from the holding potential (H.P.) of -80 mV to -40 mV, increased to maximum amplitude at around +10 mV, and became smaller with progressively higher depolarizing pulses to reverse at around +60 mV. The inactivation time constant $(\tau)$, fitted from the long duration test potential (2 sec) was $1295.2{\pm}126.8$ msec $(n=20,\;1\;day\;of\;culture,\;mean\;{\pm}S.E.M.)$ and the kinetic parameters were not altered along the culture duration. Nicardipine $(10\;{\mu}M)$ blocked the current almost completely. Among treated divalent cations such as $Cd^{2+},\;Co^{2+},\;Ni^{2+},\;Zn^{2+}\;and\;,Mn^{2+},\;Cd^{2+}$ was the most potent blocker on VDCC. When the depolarizing step pulse from -80 mV to 10 mV was applied, the equilibrium dissociation constant $(K_d)$ of $Cd^{2+}\;was\;39\;{\mu}M,\;K_d\;of\;Co^{2+}\;was\;100\;{\mu}M\;and\;K_d\;of\;Ni^{2+}];was];780{\mu}M.$ The principal findings of this study are as follows. First, the majority of $Ca^{2+}$ channels in rat chromaffin cells are well classified to L-type $Ca^{2+}$ channel in the view of kinetics and pharmacology. Second, all divalent cations tested could block the $Ca^{2+}$ current and the most potent blocker among the tested was $Cd^{2+}$.

• 대한환경공학회지
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• 제36권10호
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• pp.685-690
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• 2014

하수처리시설 초과유량에 대한 처리 규제 입법 예고로 인해 강우 월류수 처리에 대한 관심이 증가하고 있다. 본 연구에서는 강우 월류수 염소(차아염소산나트륨) 소독 시 소독제 농도(0.11-4.0 mg $Cl_2/L$), pH (6.5-8.0), 온도($15-25^{\circ}C$), 암모니아 농도(10-41 mg N/L), 부유물질(91-271 mg SS/L)이 대장균군수 감소 속도에 미치는 영향을 고찰하였다. 차아염소산나트륨 농도 효과는 반속도 상수가 1.212mg $Cl_2/L$인 saturation-type model로 잘 모사되었다. 소독 반응 속도는 SS와 pH 증가에 따라 감소되는 반면, 온도에 따라서는 증가하였고, 암모니아 농도에는 영향을 받지 않았다. 월류수 유입 조건을 $1{\times}10^5MPN/mL$, 271 mg SS/L, $15^{\circ}C$, pH 8.0로 가정할 때, 염소 주입 농도 1 mg/L, 수리학적 체류시간 1.25 분인 염소 소독조를 통해 입법예고 된 수질 기준의 1/3 수준인 대장균군수 1,000개/mL를 달성할 수 있을 것으로 계산되어, 염소 소독이 강우 월류수 소독에 유효하게 사용될 수 있을 것으로 판단된다.

• The Korean Journal of Physiology and Pharmacology
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• 제20권2호
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• pp.193-200
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• 2016

Sertraline, a selective serotonin reuptake inhibitor (SSRI), has been reported to lead to cardiac toxicity even at therapeutic doses including sudden cardiac death and ventricular arrhythmia. And in a SSRI-independent manner, sertraline has been known to inhibit various voltage-dependent channels, which play an important role in regulation of cardiovascular system. In the present study, we investigated the action of sertraline on Kv1.5, which is one of cardiac ion channels. The effect of sertraline on the cloned neuronal rat Kv1.5 channels stably expressed in Chinese hamster ovary cells was investigated using the whole-cell patch-clamp technique. Sertraline reduced Kv1.5 whole-cell currents in a reversible concentration-dependent manner, with an $IC_{50}$ value and a Hill coefficient of $0.71{\mu}M$ and 1.29, respectively. Sertraline accelerated the decay rate of inactivation of Kv1.5 currents without modifying the kinetics of current activation. The inhibition increased steeply between -20 and 0 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to +10 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance ${\delta}$ of 0.16. Sertraline slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of sertraline, were superimposed. Inhibition of Kv1.5 by sertraline was use-dependent. The present results suggest that sertraline acts on Kv1.5 currents as an open-channel blocker.

• BMB Reports
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• 제29권4호
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• pp.277-285
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• 1996

In Pseudomonas fluorescens grown on malonate as sole carbon source, acetyl-CoA synthetase was induced, suggesting that malonate is metabolized through acetate and then acetyl-CoA. Acetyl-CoA synthetase was purified 18.6-fold in 4 steps to apparent homogeneity. The native molecular mass of the enzyme estimated by a native acrylamide gel electrophoresis was 130 kDa. The enzyme was composed of two identical subunits with a molecular mass of 67 kDa. Optimum pH was 70. The acetyl-CoA synthetase showed typical Michaelis-Menten kinetics for the substrates, acetate, ATP and CoA, whose $K_m$ values were calculated to be 33.4, 74.8, and 40.7 mM respectively. Propionate. butyrate and pentanoate were also used as substrates by the enzyme, but the rate of the formation of the CoA derivatives was decreased in the order of the increase in carbon number. The enzyme was inhibited by the group-specific reagents diethylpyro-carbonate, 2,3-butanedione, pyridoxal-5'-phosphate and N-bromosuccinimide. In the presence of substrates the inactivation rate of the enzyme, by all of the group-specific reagents mentioned above decreased, indicating the presence of catalytically essential histidine, arginine, lysine and tryptophan residues at or near the active site. Preincubation of the enzyme with ATP, $Mg^{2+}$ resulted in the increase of its susceptibility to diethylpyrocarbonate, suggesting that ATP, $Mg^{2+}$ may induce a conformational change in the active site exposing the essential histidine residue to diethylpyrocarbonate. The enzyme was acetylated in the presence of acetyl-CoA, indicating that this is one of acyl-enzyme.

• The Korean Journal of Physiology and Pharmacology
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• 제5권5호
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• pp.413-421
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• 2001

An impaired smooth muscle cell (SMC) relaxation of coronary artery by alteration of $K^+$ channels would be the most potential explanation for reduced coronary reserve in left ventricular hypertrophy (LVH), however, this possibility has not been investigated. We performed morphometrical analysis of the coronary artery under electron microscopy and measured $Ca^{2+}-activated\;K\;(K_{Ca})$ currents and delayed rectifier K $(K_{dr})$ currents by whole-cell and inside-out patch-clamp technique in single coronary arterial SMCs from rabbits subjected to isoprenaline-induced cardiac hypertrophy. Coronary arterial SMCs underwent significant changes in ultrastructure. The unitary current amplitude and the open-state probability of $K_{Ca}$ channel were significantly reduced in hypertrophy without open-time and closed-time kinetic. The concentration-response curve of $K_{Ca}$ channel to $Ca^{2+}$ is shifted to the right in hypertrophy. The reduction in the mean single channel current and increase in the open channel noise of $K_{Ca}$ channel by TEA were more sensitive in hypertrophy. $K_{dr}$ current density is significantly reduced in hypertrophy without activation and inactivation kinetics. The sensitivity of $K_{dr}$ current on 4-AP is significantly increased in hypertrophy. This is the first study to report evidence for alterations of $K_{Ca}$ channels and $K_{dr}$ channels in coronary SMCs with LVH. The findings may provide some insight into mechanism of the reduced coronary reserve in LVH.

• The Korean Journal of Physiology and Pharmacology
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• 제20권1호
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• pp.75-82
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• 2016

Paroxetine, a selective serotonin reuptake inhibitor (SSRI), has been reported to have an effect on several ion channels including human ether-a-go-go-related gene in a SSRI-independent manner. These results suggest that paroxetine may cause side effects on cardiac system. In this study, we investigated the effect of paroxetine on Kv1.5, which is one of cardiac ion channels. The action of paroxetine on the cloned neuronal rat Kv1.5 channels stably expressed in Chinese hamster ovary cells was investigated using the whole-cell patch-clamp technique. Paroxetine reduced Kv1.5 whole-cell currents in a reversible concentration-dependent manner, with an $IC_{50}$ value and a Hill coefficient of $4.11{\mu}M$ and 0.98, respectively. Paroxetine accelerated the decay rate of inactivation of Kv1.5 currents without modifying the kinetics of current activation. The inhibition increased steeply between -30 and 0 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to 0 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance ${\delta}$ of 0.32. The binding ($k_{+1}$) and unbinding ($k_{-1}$) rate constants for paroxetine-induced block of Kv1.5 were $4.9{\mu}M^{-1}s^{-1}$ and $16.1s^{-1}$, respectively. The theoretical $K_D$ value derived by $k_{-1}/k_{+1}$ yielded $3.3{\mu}M$. Paroxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of paroxetine, were superimposed. Inhibition of Kv1.5 by paroxetine was use-dependent. The present results suggest that paroxetine acts on Kv1.5 currents as an open-channel blocker.