• 한국축산식품학회지
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• 제42권5호
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• pp.800-815
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• 2022

This study aimed to obtain high Fischer's ratio oligopeptides from goat whey (HFO) and investigate antioxidant property of it. Hydrolysis of goat whey was done with the approach of sequential digestion of pepsin and flavourzyme. With the adsorption of aromatic amino acids by activated carbon, HFO with a Fischer's ratio of 27.070 and a molecular weight of 200-1,000 Da were obtained, and the branched-chain amino acids accounted for 22.87%. Then the antioxidant activity of HFO was evaluated. At the concentrations of 2.0 mg/mL and 0.50 mg/mL, HFO scavenged 77.27% and 99.63% of 1,1-diphenyl-2-picrylhydrazyl and 3-ethylbenzthiazoline-6-sulphonate free radicals respectively. The scavenging rate of HFO against hydroxyl radicals reached 92.31% at the concentration of 0.25 mg/mL. Animal experiments demonstrated that HFO could moderate the changes of malondialdehyde, superoxide dismutase and glutathione peroxidase caused by CCl₄-induced oxidative stress in vivo. This study indicated that HFO from goat whey was capable of oxidation resistance both in vivo and in vitro, which provided a scientific basis for the high-value processing and application of goat milk whey.

• Molecules and Cells
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• 제46권8호
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• pp.496-512
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• 2023

A fructose-enriched diet is thought to contribute to hepatic injury in developing non-alcoholic steatohepatitis (NASH). However, the cellular mechanism of fructose-induced hepatic damage remains poorly understood. This study aimed to determine whether fructose induces cell death in primary hepatocytes, and if so, to establish the underlying cellular mechanisms. Our results revealed that treatment with high fructose concentrations for 48 h induced mitochondria-mediated apoptotic death in mouse primary hepatocytes (MPHs). Endoplasmic reticulum stress responses were involved in fructose-induced death as the levels of phosho-eIF2α, phospho-C-Jun-N-terminal kinase (JNK), and C/EBP homologous protein (CHOP) increased, and a chemical chaperone tauroursodeoxycholic acid (TUDCA) prevented cell death. The impaired oxidation metabolism of fatty acids was also possibly involved in the fructose-induced toxicity as treatment with an AMP-activated kinase (AMPK) activator and a PPAR-α agonist significantly protected against fructose-induced death, while carnitine palmitoyl transferase I inhibitor exacerbated the toxicity. However, uric acid-mediated toxicity was not involved in fructose-induced death as uric acid was not toxic to MPHs, and the inhibition of xanthine oxidase (a key enzyme in uric acid synthesis) did not affect cell death. On the other hand, treatment with inhibitors of the nicotinamide adenine dinucleotide (NAD)⁺-consuming enzyme CD38 or CD38 gene knockdown significantly protected against fructose-induced toxicity in MPHs, and fructose treatment increased CD38 levels. These data suggest that CD38 upregulation plays a role in hepatic injury in the fructose-enriched diet-mediated NASH. Thus, CD38 inhibition may be a promising therapeutic strategy to prevent fructose-enriched diet-mediated NASH.

• 부식과 방식
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• 제12권1호
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• pp.30-38
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• 2013

원전의 구조적 건전성에 문제가 될 수 있는, 오스테나이트계 합금의 환경조장균열(EAC)에 대한 거동을 실험적인 결과와 문헌 조사를 통해 분석하였다. 일차측 환경에서 주기적인 반복하중을 받을 때에는 기계적인 피로균열에 더해 수소유기균열이나 동적변형시효 등으로 인한 가속화 메커니즘을 통해 피로수명 감소가 나타났다. 따라서 EAF에 대한 저항성은 전반적인 부식저항성이 우수한 니켈기합금이 스테인리스강보다 크게 나타났다. 그러나 일정한 하중을 받을 때에는 내부산화에 의해 국부적인 취약부인 입계로의 빠른 균열의 생성과 진전이 나타나 일차수 응력부식균열(PWSCC)이라는 형태로 발생한다고 여겨진다. 이때는 니켈-크롬의 비율이 내부산화 저항성에 영향을 미쳐, 비율이 낮은 스테인리스강은 높은 저항성을 가지고, 비율이 높은 니켈기합금은 낮은 저항성을 가진다. 그러나 아직 이러한 균열 메커니즘에 대한 명확한 이해가 부족하므로, 명확히 규명하기 위해서는 추가적인 연구가 필요하다.

• Journal of Electrochemical Science and Technology
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• 제14권4호
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• pp.388-396
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• 2023

Photoelectrochemical (PEC) water splitting is a vital source of clean and sustainable hydrogen energy. Moreover, the large-scale H₂ production is currently necessary, while long-term stability and high PEC activity still remain important issues. In this study, a GaN-based photoelectrode was modified by an additional NH₃ treatment (900℃ for 10 min) and its PEC behavior was monitored. The bare GaN exhibited a highly crystalline wurtzite structure with the (002) plane and the optical bandgap was approximately 3.2 eV. In comparison, the NH₃-treated GaN film exhibited slightly reduced crystallinity and a small improvement in light absorption, resulting from the lattice stress or cracks induced by the excessive N supply. The minor surface nanotexturing created more surface area, providing electroactive reacting sites. From the surface XPS analysis, the formation of an N-Ga-O phase on the surface region of the GaN film was confirmed, which suppressed the charge recombination process and the positive shift of E_FB. Therefore, these effects boosted the PEC activity of the NH₃-treated GaN film, with J values of approximately 0.35 and 0.78 mA·cm^-2 at 0.0 and 1.23 V_RHE, respectively, and an onset potential (V_on) of -0.24 V_RHE. In addition, there was an approximate 50% improvement in the J value within the highly applied potential region with a positive shift of V_on. This result could be explained by the increased nanotexturing on the surface structure, the newly formed defect/trap states correlated to the positive V_on shift, and the formation of a GaO_xN_1-x phase, which partially blocked the charge recombination reaction.

• 한국정보전자통신기술학회논문지
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• 제17권3호
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• pp.146-154
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• 2024

본 논문에서는 액정디스플레이 산업에서 러빙공정의 대안으로 브러시 모(brush hair)를 이용한 편리한 액정분자 정렬 방식을 제시합니다. 졸겔 공정을 이용해서 타이타늄 스트론튬 이트륨 지르코늄 산화물(TiSrYZrO) 용액을 제조하였고, 원스텝(one-step) 브러시 코팅 공정을 통해 TiSrYZrO 배향막 제조와 액정분자 배향을 통합하였다. 경화온도가 높아짐에 따라 액정 셀의 액정분자 정렬 상태가 향상되었고, 코팅 표면의 brush hair 움직임에 의한 전단 응력에 기인하는 물리적 표면 이방성 구조 형성으로 인해 균일한 액정분자 정렬을 유도하였다. 균일하고 균질한 액정분자 정렬은 편광 광학 현미경과 선경사 각 측정을 통해 확인하였다. X-선 광전자 분광법으로 열산화를 통해 금속산화물로 잘 형성된 TiSrYZrO 박막을 확인하였고, 우수한 광학 투명성이 있음을 검증하였다. 이러한 결과로부터 러빙공정의 대안으로 brush hair를 이용한 편리한 액정분자 정렬 방식이 실행 가능한 차세대 기술이 될 것이라고 기대된다.

• 한국식품영양학회지
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• 제28권1호
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• pp.34-39
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• 2015

본 연구는 식용 버섯의 조리방법에 따른 항산화 생리활성의 평가를 위해 수행되었으며, 산화적 스트레스에 의한 DNA 손상 감소 효과를 통해 조리방법을 달리한 버섯 추출물의 유전독성학적 방호효과를 살펴보았다. Human lymphocyte에 조리방법을 달리한 3가지 버섯(느타리, 팽이, 표고)의 추출물을 처리하고, hydrogen peroxide($H_2O_2$)로 산화적 손상을 준 후, DNA 감소 효과를 Comet assay로 평가한 결과, 모든 시료군에서 산화적 손상에 의한 DNA 손상 감소 효과를 나타냈다. 3가지 버섯 모두 비조리군이 조리군보다 높은 효과를 나타냈는데, 이는 조리과정에 의한 페놀성 화합물의 감소로 인한 것으로 보이며, 조리군 중에서 볶기와 전이 비교적 낮은 DNA 손상 감소 효과를 나타낸 것은 조리 시 첨가되었던 대두유의 가열 산화에 의한 것으로 사료된다. 결론적으로, 조리된 버섯은 생버섯에 비해 산화적 스트레스에 의한 DNA 손상 감소효과가 낮으나, 양성 대조군과 비교하였을 때 손상을 유의적으로 감소시킨 것으로 나타났다. 또한, 본 연구에서 사용한 네 가지 조리법(굽기, 데치기, 볶기, 전) 중 DNA 손상 감소에 효과적인 조리법은 대두유를 사용하지 않은 굽기와 데치기인 것으로 판단된다.

• 대한의생명과학회지
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• 제12권2호
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• pp.81-89
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• 2006

The ischemia-responsive 94 gene (irp94) encoding a 94 kDa endoplasmic reticulum resident protein was investigated its molecular properties associated with unfoled protein responses. First, the expression of irp94 mRNA was tested after the reperfusion of the transient forebrain ischemia induction at the central nervous system in three Mongolian gerbils. Second, irp94 expression in PC12 cells, which are derived from transplantable rat pheochromocytoma cultured in the DMEM media, was tested at transcriptional and translational levels. The half life of irp94 mRNA was also determined In PC12 cells. Last, the changes of irp94 mRNA expression were investigated by the addition of various ER stress inducible chemicals (A23187, BFA, tunicamycin, DTT and $H_2O_2$) and proteasome inhibitors, and heat shock. High level expression of irp94 mRNA was detected after 3 hours reperfusion in the both sites of the cerebral cortex and hippocampus of the gerbil brain. The main regulation of irp94 mRNA expression in PC 12 cells was determined at the transcriptional level. The half life of irp94 mRNA in PC12 cells was approximately 5 hours after the initial translation. The remarkable expression of irp94 mRNA was detected by the treatment of tunicamycin, which blocks glycosylation of newly synthesized polypeptides, and $H_2O_2$, which induces apoptosis. When PC12 cells were treated with the cytosol proteasome inhibitors such as ALLN (N-acetyl-leucyl-norleucinal) and MG 132 (methylguanidine), irp94 mRNA expression was increased. These results indicate that expression of irp94 was induced by ER stress including oxidation condition and glycosylation blocking in proteins. Expression of irp94 was increased when the cells were chased after heat shock, suggesting that irp94 may be involved in recovery rather than protection against ER stresses. In addition, irp94 expression was remarkably increased when cytosol proteasomes were inhibited by ALLN and MG 132, suggesting that irp94 plays an important role for maintaining the ERAD (endoplasmic reticulum associated degradation) function.

• 동의생리병리학회지
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• 제27권5호
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• pp.611-616
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• 2013

Alcoholic liver disease (ALD) is a major cause of morbidity and mortality around the world. Although much progress has been made in understanding the pathogenesis of ALD, there remains no effective therapy for it. Accumulated evidence indicates that oxidative stress is the main pathological factors in the development of ALD. Ethanol administration causes accumulation of reactive oxygen species (ROS), including superoxide, hydroxyl radical, and hydrogen peroxide. ROS, in turn, cause lipid peroxidation of cellular membranes, and protein and DNA oxidation, which results in hepatocyte injury. In addition to pro-oxidants formation, antioxidants depletion caused by ethanol administration also results in oxidative stress. The objective of this study is to investigate the effects of Shiryung-tang extract on the chronic alcoholic liver injury induced by EtOH. Male Sprague Dawley rats were used in this study. All rats were maintained under standard laboratory conditions ($23{\pm}1^{\circ}C$, 12h light/12h dark cycles). All animals (n=30) were randomly divided into following groups: (1) Normal group, treated with distilled water (n=10); (2) Control group, treated with ethanol (n=10); (3) Sample group, treated with ethanol + pharmacopuncture (n=10). For oral administration of ethanol in Control and Sample group, the ethanol was dissolved in distilled water in concentrations of 25%(v/v). Throughout the experiment of 8 week, the rats were allowed free access to water and standard chow. Sample group were administrated by Shiryung-tang extract daily for 8 weeks. Control group were given normal saline for same weeks. As a results, the oral administration of ethanol for 8 weeks leads to hepatotoxicity. The levels of hepatic marker such as HDL-cholesterol, triglyceride, aspartate aminotransferase and alanine aminotransferase were altered. The ethanol also increased lipid peroxidation and depletion of antioxidant enzyme activities as well as hepatic tissue injury. However, the treatment of Shiryung-tang extract prevented all the alterations induced by ethanol and returned their levels to near normal. These data suggest that Shiryung-tang extract could have a beneficial effect in inhibiting the oxidative damage induced by chronic ethanol administration. Therefore, Shiryung-tang extract can be a candidate to protect against EtOH-induced liver injury.

• The Plant Pathology Journal
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• 제30권4호
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• pp.343-354
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• 2014

Rice blast disease caused by Magnaporthe oryzae is one of the most serious diseases of cultivated rice (Oryza sativa L.) in most rice-growing regions of the world. In order to investigate early response genes in rice, we utilized the transcriptome analysis approach using a 300 K tilling microarray to rice leaves infected with compatible and incompatible M. oryzae strains. Prior to the microarray experiment, total RNA was validated by measuring the differential expression of rice defense-related marker genes (chitinase 2, barwin, PBZ1, and PR-10) by RT-PCR, and phytoalexins (sakuranetin and momilactone A) with HPLC. Microarray analysis revealed that 231 genes were up-regulated (>2 fold change, p < 0.05) in the incompatible interaction compared to the compatible one. Highly expressed genes were functionally characterized into metabolic processes and oxidation-reduction categories. The oxidative stress response was induced in both early and later infection stages. Biotic stress overview from MapMan analysis revealed that the phytohormone ethylene as well as signaling molecules jasmonic acid and salicylic acid is important for defense gene regulation. WRKY and Myb transcription factors were also involved in signal transduction processes. Additionally, receptor-like kinases were more likely associated with the defense response, and their expression patterns were validated by RT-PCR. Our results suggest that candidate genes, including receptor-like protein kinases, may play a key role in disease resistance against M. oryzae attack.

• Nutrition Research and Practice
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• 제8권5호
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• pp.509-515
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• 2014

BACKGROUND/OBJECTIVES: The root of Vitis amurensis Ruprecht, a sort of wild-growing grape, has been used in oriental medicine for treatment of skin ailments; however, its dermatological activity is not sufficiently understood. The aim of this study was to investigate tyrosinase inhibitory and anti-melanogenic activities of V. amurensis Ruprecht root methanol extract (VARM) in B16F10 mouse melanoma cells and to attempt to isolate and identify the active compound issued from VARM. MATERIALS/METHODS: Anti-melanogenic activity of VARM was analyzed in ${\alpha}$-melanocyte stimulating hormone (MSH)-stimulated B16F10 cells through evaluation of antioxidative activity as well as inhibited tyrosinase activity and melanin contents compared with those of kojic acid and arbutin. After anti-melanogenic analysis of VARM, serial fractionation, nuclear magnetic resonance (NMR), and thin layer chromatorgraphy (TLC) were applied for identification of active compounds contained in VARM. RESULTS: VARM significantly inhibited oxidative stress and tyrosinase activity and attenuated ${\alpha}$-MSH-induced melanin production in B16F10 cells. For isolation of active compounds, VARM was fractionated using a series of organic solvents, including dichloromethane ($CH_2Cl_2$), ethyl acetate (EtOAc), and n-butanol (n-BuOH). Among fractions showing anti-melanogenic activity, the CH2Cl2 fraction induced the most potent attenuation of melanogenesis without cytotoxicity and the major compound in the $CH_2Cl_2$ fraction was identified as betulinic acid. Betulinic acid isolated from the $CH_2Cl_2$ fraction of VARM significantly attenuated ${\alpha}$-MSH-induced melanogenesis in a dose dependent manner, which was stronger than that of arbutin used as a positive control. CONCLUSIONS: These results indicate that VARM inhibits oxidative stress, tyrosinase activity, and ${\alpha}$-MSH-induced melanogenesis in B16F10 cells, due primarily to the active compound, betulinic acid, in the $CH_2Cl_2$ fraction.