• 약학회지
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• 제48권3호
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• pp.213-217
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• 2004

For the determination of glutathione S-transferase activity, a new method was established by using HPLC system. Moreover, amount of enzyme for a optimum reaction was determined by a comparative study with a variety concentration of enzyme. Using a established method, activity of glutathione S-transferase that is alcohol metabolizing enzyme was investigated on the fruit of Hovenia dulcis Thunb. As the result of experiment, EtOH and $H_2O$ extracts of the fruit of Hovenia dulcis Thunb showed visible a synergistic effect of glutathione S-transferase activity. On a continuous experiment, EtOH and $H_2O$ extracts of the fruit of Hovenia dulcis Thunb showed alcohol decomposition activity on the in vivo test using rat. These results suggest that the fruit of Hovenia dulcis Thunb may be useful in the prevention of hangover.

• 식물병연구
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• 제27권3호
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• pp.99-106
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• 2021

The fungal isolate Isaria javanica pf185 has potential as a mycopesticide because it demonstrates insecticidal activity against the green peach aphid and antifungal activity against Colletotrichum gloeosporioides. For commercialization of this isolate, determination of the optimal and least expensive culture conditions is required; however, these data are not currently available. This study describes the conditions for optimal development of conidia and production of metabolites for the biocontrol of the fungal pathogen. The optimal culture conditions were examined using cultures on solid agar and liquid media. High growth temperature enhanced spore formation but reduced antifungal activity in both solid and liquid media. The highest spore yield was obtained in a medium containing glucose as a carbon source and yeast extract as a nitrogen source. Soybean powder and wheat bran were effective nitrogen sources that promoted spore production and antifungal activity of the isolate. These results revealed the basic, cost-effective growth media for commercial production of a biopesticide with insecticidal and antifungal properties for use in integrated pest management.

• Journal of Pharmaceutical Investigation
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• 제36권5호
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• pp.309-314
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• 2006

The multicellular layers(MCL) of human cancer cells is a three dimensional(3D) in vitro model for human solid tumors which has been used primarily for the assessment of avascular penetration of anti-cancer drugs. For anti-cancer drugs with penetration problem, MCL represents a good experimental model that can provide clinically relevant data. Calcein-AM is a fluorescent dye that demonstrates the cellular vitality in a graded manner in cancer cell culture system. In the present study, we evaluated the use of calcein-AM for determination of anti-proliferative activity of anti-cancer agents in MCL model of DLD-1 human colorectal cancer cells. Optical sectioning of confocal imaging was compromised with photonic attenuation and penetration barrier in the deep layers of MCL. By contrast, fluorescent measurement on the cryo-sections provided a feasible alternative. Cold pre-incubation did not enhance the calcein-AM distribution to a significant degree in MCL of DLD-1 cells. However, the simultaneous determination of drug penetration and cellular vitality appeared to be possible in drug treated MCL. In conclusion, these data suggest that calcein-AM can be used for the simultaneous determination of drug-induced anti-proliferative effect and drug penetration in MCL model.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.845-849
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• 2010

A gold nanoparticles modified carbon paste electrode (GN-CPE) has been used for the determination of atenolol (ATN) in drug formulations by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronocoulometric methods. The results revealed that the modified electrode shows an electrocatalytic activity toward the anodic oxidation of atenolol by a marked enhancement in the current response in buffered solution at pH 10.0. The anodic peak potential shifts by -80.0 mV when compared with the potential using bare carbon paste electrde. A linear analytical curve was observed in the range of $1.96\;{\times}\;10^{-6}$ to $9.09\;{\times}\;10^{-4}\;mol\;L^{-1}$. The detection limit for this method is $7.3\;{\times}\;10^{-8}\;mol\;L^{-1}$. The method was then successfully applied to the determination of atenolol in tablets and human urine. The percent recoveries in urine ranged from 92.0 to 110.0%.

• Molecules and Cells
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• 제46권12호
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• pp.727-735
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• 2023

Stem cells require high amounts of energy to replicate their genome and organelles and differentiate into numerous cell types. Therefore, metabolic stress has a major impact on stem cell fate determination, including self-renewal, quiescence, and differentiation. Lysosomes are catabolic organelles that influence stem cell function and fate by regulating the degradation of intracellular components and maintaining cellular homeostasis in response to metabolic stress. Lysosomal functions altered by metabolic stress are tightly regulated by the transcription factor EB (TFEB) and TFE3, critical regulators of lysosomal gene expression. Therefore, understanding the regulatory mechanism of TFEB-mediated lysosomal function may provide some insight into stem cell fate determination under metabolic stress. In this review, we summarize the molecular mechanism of TFEB/TFE3 in modulating stem cell lysosomal function and then elucidate the role of TFEB/TFE3-mediated transcriptional activity in the determination of stem cell fate under metabolic stress.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.667-671
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• 2003

표고버섯 추출물을 이용한 total phenolic compounds 와 flavonoid 함량 분석 후 표고버섯의 GST activity를 측정한 결과 높은 GST 활성을 가지는 추출물은 total phenolic compounds의 함량이 높게 나타난 증류수 추출물로 나타났으며, flavonoid의 함량이 높게 나타난 ethanol, methanol 추출물에서는 비교적 낮게 나타났다. 이는 표고버섯 추출물 중 GST 활성을 나타내는 물질은 flavonoid 외의 다른 total phenolic compounds 로 추정된다.

• Toxicological Research
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• 제22권1호
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• pp.39-45
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• 2006

As the antioxidant and free radical scavenger, glutathione (GSH) participates in the preservation of cellular redox status and defense against reactive oxygen species and xenobiotics. Glutamate-cysteine ligase (GCL; also known as ${\gamma}$-glutamylcysteine synthetase, EC 6.3.2.2) is the rate limiting enzyme in GSH synthesis. In the present study, the accurate method for determination of GCL activity in crude liver extracts was developed by measuring both ${\gamma}$-glutamylcysteine and GSH from cysteine in the presence of glutamate, glycine and an ATP-generating system. We added glycine to promote the conversion of ${\gamma}$-glutamylcysteine to GSH, and to minimize the possibility of ${\gamma}$-glutamylcysteine metabolism to cysteine and oxoproline by ${\gamma}$-glutamylcyclotransferase. We established optimal conditions and substrate concentrations for the enzyme assay, and verified that inhibition of GCL by GSH did not interfere with this assay. Therefore, this assay of hepatic GCL under optimal conditions could provide a more accurate measurement of this enzyme activity in the crude liver extracts.

• 산업기술연구
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• 제19권
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• pp.197-208
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• 1999

The process of localization of cracks and movement of the fracture process zone(FPZ) was studied using the acoustic-emission(AE) techniques. The rate of AE events and sources of AE activity were studied for mortar and rock specimens loaded in uniaxial compression. A series of transducers could be used to detect and AE activity. Based on the time differences between detection of the event at different transducers, source of AE activity could be detected. The rate of AE events increased sharply before peak load. The highest rate occurred just after peak load was attained. The effective crack length estimated from the modified linear-elastic fracture mechanics seemed consistent with the optical and AE measurements.

• 한국미생물·생명공학회지
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• 제24권5호
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• pp.579-584
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• 1996

The molecular weight of the purified nucleoside oxidase estimated by gel filtration column chromatography was 480,000 and the enzyme protein was composed of four nonidentical subunits (81,000, 69,000, 32,000 and 16,000). On the basis of the visible absorption spectra and the enzymatic determination of the purified enzyme, the enzyme was supposed as a hemoprotein and also a flavoprotein containing 3 moles of FAD per I mole of enzyme. The isoelectric point of the enzyme was pH 5.1. Addition of metal salts such as 1 mM SnCl$_{2}$ and PbCl$_{2}$ into an enzyme reaction solution inhibited the enzyme activity by 94 and 90%, respectively. The enzyme activity was also lost significantly by hemoenzyme inhibitors such as NaCN and NaN$_{3}$ and flavoenzyme inhibitor, acriflavine and quinacrine. The maximal nucleoside oxidase activity was observed at pH 7.0 and 55$\circ$C. The nucleoside oxidase was relatively stable in the range of pH 5.5-9.0 and below 55$\circ$C.

• 약학회지
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• 제32권1호
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• pp.40-49
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• 1988

There is evidence that brain norepinephrine may play a role in experimentally induced seizures in animals. Thus the present experiments were undertaken in an attempt to explore the role of brain norepinephrine in anticonvulsant activity of clonazepam. 6-Hydroxydopamine was given to newborn rats and PTZ-induced seizures were tested $70{\sim}90$ days after birth and the rats were killed for determination of brain norepinephrine 8 days after the seizure test. Depletion of norepinephrine in the rat brain significantly potentiated the PTZ-induced convulsions and antagonized the effect of clonazepam on clonic seizures, tonic seizures and the number of seizures, but the latency to the seizure and the mortality has not been altered. However the 6-hydroxydopamine-induced antagonism of anticonvulsant action was surmountable by increasing the dose of clonazepam. These results show that brain norepinephrine may play an important role in seizure susceptability as well as in the anticonvulsant activity of clonazepam in rats.