• 한국환경농학회지
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• 제27권1호
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• pp.86-91
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• 2008

물에 대한 용해도가 높아 수질오염을 시킬 가능성이 있는 제초제 dicamba를 분해시키기 위하여 zerovalent iron 및 Fenton reagent를 처리하여 분해되는 정도와 분해산물을 동정하였다. ZVI에 의한 dicamba의 분해 반응속도는 pH 3.0이 pH 5.0 조건보다 빠르게 진행되었으며 처리된 ZVI의 양이 0.05%에서 1.0%(w/v)로 증가됨에 따라 분해율이 증가되어 반응 3시간 이내에 90% 이상이 분해되었다. 그러나 ZVI의 처리량이 증가됨에 따라 반응후 용액의 pH 상승으로 인하여 dicamba의 분해효율은 증가되지 않았다. ZVI 처리에 의해 생성된 dicamba의 분해 산물을 diazomethane 유도체화 과정을 거쳐 GC-MS로 분석한 결과 dicamba 구조내의 잔기가 없는 부분에 hydroxylation된 형태인 4-hydroxy dicamba 혹은 5-hydroxy dicamba, 4,5-dihydroxy dicamba 그리고 dicamba 구조내의 carboxyl기가 hydroxyl기로 전환된 형태인 3,6-dichloro-2-methoxyphenol로 예상되는 compound를 확인하였다. 이러한 반응산물은 ferric sulfate를 이용한 Fenton 반응에서 조사된 dicamba의 분해 산물과 동일한 것으로 확인되었다. 그러나 ZVI에 의한 dicamba의 탈염소화 분해산물은 확인되지 않았다. 따라서 호기적 조건 하에서 ZVI 처리에 의해 유도되는 제초제 dicamba의 주된 분해 경로는 환원반응보다는 반응용액 중에 존재하는 $O_2$와 $Fe^0$의 산화에 의해 생성된 $Fe^{2+}$ 사이의 Fenton 반응과 같은 산화반응인 것으로 사료된다.

• BMB Reports
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• 제49권11호
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• pp.617-622
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• 2016

Oxidative stress is closely associated with various diseases and is considered to be a major factor in ischemia. NAD(P)H: quinone oxidoreductase 1 (NQO1) protein is a known antioxidant protein that plays a protective role in various cells against oxidative stress. We therefore investigated the effects of cell permeable Tat-NQO1 protein on hippocampal HT-22 cells, and in an animal ischemia model. The Tat-NQO1 protein transduced into HT-22 cells, and significantly inhibited against hydrogen peroxide ($H_2O_2$)-induced cell death and cellular toxicities. Tat-NQO1 protein inhibited the Akt and mitogen activated protein kinases (MAPK) activation as well as caspase-3 expression levels, in $H_2O_2$ exposed HT-22 cells. Moreover, Tat-NQO1 protein transduced into the CA1 region of the hippocampus of the animal brain and drastically protected against ischemic injury. Our results indicate that Tat-NQO1 protein exerts protection against neuronal cell death induced by oxidative stress, suggesting that Tat-NQO1 protein may potentially provide a therapeutic agent for neuronal diseases.

• The Korean Journal of Physiology and Pharmacology
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• 제24권1호
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• pp.69-79
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• 2020

Aging is one of the risk factors for the development of cardiovascular diseases. During the progression of cellular senescence, cells enter a state of irreversible growth arrest and display resistance to apoptosis. As a flavonoid, quercetin induces apoptosis in various cells. Accordingly, we investigated the relationship between quercetin-induced apoptosis and the inhibition of cellular senescence, and determined the mechanism of oxidative stress-induced vascular smooth muscle cell (VSMC) senescence. In cultured VSMCs, hydrogen peroxide (H₂O₂) dose-dependently induced senescence, which was associated with increased numbers of senescence-associated β-galactosidase-positive cells, decreased expression of SMP30, and activation of p53-p21 and p16 pathways. Along with senescence, expression of the anti-apoptotic protein Bcl-2 was observed to increase and the levels of proteins related to the apoptosis pathway were observed to decrease. Quercetin induced apoptosis through the activation of AMP-activated protein kinase. This action led to the alleviation of oxidative stress-induced VSMC senescence. Furthermore, the inhibition of AMPK activation with compound C and siRNA inhibited apoptosis and aggravated VSMC senescence by reversing p53-p21 and p16 pathways. These results suggest that senescent VSMCs are resistant to apoptosis and quercetin-induced apoptosis attenuated the oxidative stress-induced senescence through activation of AMPK. Therefore, induction of apoptosis by polyphenols such as quercetin may be worthy of attention for its anti-aging effects.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.78.2-79
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• 2003

Pepper defensin ( CADEFl) clone was isolated from cDNA library constructed from pepper leaves infected with avirulent strain Bv5-4a of Xanthomonu campestris pv. vesicatoria. The deduced amino acid sequence of CADEFl is 82-64％ identical to that of other plant defensins. Putative protein encoded by CADEFl gene consists of 78 amino acids and 8 conserved cysteine residues to form four structure-stabilizing disulfide bridges. Transcription of the CADEF1 gene was earlier and stronger induced by X campestris pv. vesicatoria infection in the incompatible than in the compatible interaction. CADEF1 mRNA was constitutively expressed in stem, root and green fruit of pepper. Transcripts of CADEFl gene drastically accumulated in pepper leaf tissues treated With Salicylic acid (SA), methyl jasmonate (MeJA), abscisic acid (ABA), hydrogen Peroxide (H$_2$O$_2$), benzothiadiazole (BTH) and DL-${\beta}$-amino-n-butyric acid (BABA). In situ hybridization results revealed that CADEF1 mRNA was localized in the phloem areas of vascular bundles in leaf tissues treated with exogenous SA, MeJA and ABA. Strong accumulation of CADEF1 mRNA occurred in pepper leaves in response to wounding, high salinity and drought stress. These results suggest that bacterial pathogen infection, abiotic elicitors and some environmental stresses may play a significant role in signal transduction pathway for CADEF1 gene expression.

• 한국식품저장유통학회지
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• 제12권3호
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• pp.267-274
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• 2005

천식과 관련하여 산화스트레스 (Oxidant stress)는 그 발병요인 중의 하나로 알려져 있다. 이에 본 연구는 농산물과 한약재를 이용하여 항산화 물질을 찾고자 하였으며, 시간과 비용의 단축을 위하여 HTS인 throughput screening)을 이용을 하였다. 항산화 실험과 관련하여서 DPPH(1,1-diphenyl-2-picrylhydrazyl), FRAP(ferric ion reducing antioxidant power), HO(hydroxyl radical) 소거, linoleic acid에 대한 항산화 활성 등을 시행하였다. 이후 $H_{2}O_2$에 의한 산화스트레스를 이용한 세포사멸을 유도하여 세포생존을 확인해 보았다. 실험결과 해바라기씨(Helianthus annuus), 신선초(Angelica utilis Makino), 시금치(Rehmannia glutinosa Libo) 등이 활성이 높게 나타났다. 본 연구는 여기에서 나온 hit를 이용하여 동물모델 실험을 진행하고자 한다.

• 센서학회지
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• 제4권4호
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• pp.23-28
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• 1995

백금작업전극과 광가교화된 효소고정화막을 가진 ISFET 포도당 및 자당센서가 제조되었다. 효소반응의 부산물인 과산화수소수($H_{2}O_{2}$)는 백금전극표면에서 분해되어 센서의 감지특성을 개선시키고, 광가교화 고분자(PVA-SbQ)가 효소고정화막으로 이용되어 센서의 응답시간을 단축하였다. 그리고 백금전극의 면적변화에 따라 센서의 응답크기는 증가하였다. 센서의 응답시간은 $3{\sim}5$분이었으며, $30{\sim}300mg/dl$의 포도당 및 자당농도에서 센서의 선형적인 응답을 보였다.

• 한국작물학회지
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• 제50권spc1호
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• pp.220-223
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• 2005

최근 뽕잎과 더불어 기능성 및 천연색소 자원으로서 뽕나무의 열매인 오디가 새로운 작목으로 유망시 되고 있다. 농가의 소득향상은 물론 소비자의 관심과 수요에 부응하기 위한 연구의 일환으로 오디를 수확하여 신경세포 보호활성과 항균활성에 대한 오디 추출물의 효능을 평가함으로써 오디의 기능성 및 이용성을 증대시키고자 하였다. 그 결과를 요약하면 다음과 같다. 1. 신경독성 물질 $H_2O_2$처리에 의해 유도되는 신경세포사에 대하여 오디 추출물 $10{\mu}g/ml$의 농도 처리시 $37\%$의 세포보호 효과를 나타냈으며, Oxygen-glucose deprivation (OGD)에 의하여 유발된 뇌허혈 모델에서는 오디 C3G의 경우 농도 의존형으로 세포괴사를 막았다. 특히 cyanidin의 경우는 $10{\mu}g/ml$의 농도에서 $70\%$이상의 뇌세포보호 효과를 나타냈다. 2. 오디 추출물과 C3G의 항균활성을 검정한 결과, 청일뽕 오디의 MeOH 추출물의 항균 활성이 가장 높았으나, Salmonella typhimurium 의 경우 모든 처리군에서 $70\%$ 이상의 억제 활성을 나타냈다. 모든 처리군에서 $50{\mu}l$농도보다 $100{\mu}l$농도에서 균주의 억제 활성이 높게 나타났다.

• Advances in Traditional Medicine
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• 제1권2호
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• pp.59-65
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• 2000

To clarify the toxic effect of oxidative stress, hydrogen peroxide $(H_{2}O_{2})-induced$ neurotoxicity was examined in cultured newborn mouse spinal motor neurons after spinal motor neurons were grown in the media containing various concentrations of glucose oxidase (GO). And also, the protective effect of Rhizoma gastrodiae extract against GO-induced neurotoxicity was evaluated. Cytotoxicity was expressed as a cell viability by 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay. In this study, exposure of motor neurons to GO-induced cell death significantly, in a dose- and time-dependent manners in spinal motor neuron cultures. The decrease in cell viability of motor neurons damaged by GO was proventioned by Rhizoma gastrodiae extract. These results suggest that the neuroprotective effect of Rhizoma gastrodiae extract on GO-induced neurotoxicity may result from a attenuation of $H_{2}O_{2}-induced$ oxidative stress.

• 대한수의학회지
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• 제44권3호
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• pp.475-482
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• 2004

For the induction of arthropathy, 4% hydrogen peroxide ($H_2O_2$) was injected for 4 weeks into the intra-articular space of the 25 New Zealand white rabbits to damage articular cartilage. The verification of arthropathy induction and the effect of scan-bio laser treatment were determined by measuring superoxide dismutase (SOD) activity, by observing gross and histopathologic findings. The SOD activity increased by about 40% in arthropathy group, as compared to controls. Although SOD activity in arthropathy group was not significantly different from the 2-week group, it was significantly different from the 4-week control and treatment groups. There was also a significant difference between the 4-week control and treatment groups. Grossly, erosions formed on the articular cartilage surface, and the lateral femoral condyle was damaged in arthropathy group. In comparison, there was slight, but not significant, progression of the lesion in the 2-week control group, and no difference between the 2-week treatment and control groups. Conversely, severe erosions damaged the articular cartilage in the 4-week control group. Cartilage proliferation was seen in gross observations in the 4-week treatment group, suggesting a treatment effect. Histopathologically, there was slight articular surface damage and apoptosis in arthropathy group, and serious cartilage damage, despite slight chondrocyte proliferation, in the 4-week control group. By contrast, the 4-week treatment group showed chondrocyte replacement, with close to normal articular cartilage on the articular surface. There was significant cartilage proliferation with regeneration of the articular cartilage on the articular surface in the group treated with low-level laser, as compared to control group, when arthropathy was induced by $H_2O_2$ injections. Therefore, low-level laser was effective in the treatment of chemically induced arthropathy.

• Journal of Periodontal and Implant Science
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• 제42권1호
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• pp.13-19
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• 2012

Purpose: The aim of this study was to examine whether a previous peri-implantitis site can affect osseointegration, by comparing implant placement at a site where peri-implantitis was present and at a normal bone site. A second aim of this study was to identify the tissue and bone reaction after treating the contaminated implant surface to determine the optimal treatment for peri-implant diseases. Methods: A peri-implant mucositis model for dogs was prepared to determine the optimal treatment option for peri-implant mucositis or peri-implantitis. The implants were inserted partially to a length of 6 mm. The upper 4 mm part of the dental implants was exposed to the oral environment. Simple exposure for 2 weeks contaminated the implant surface. After 2 weeks, the implants were divided into three groups: untreated, swabbed with saline, and swabbed with $H_2O_2$. Three implants from each group were placed to the full length in the same spot. The other three implants were placed fully into newly prepared bone. After eight weeks of healing, the animals were sacrificed. Ground sections, representing the mid-buccal-lingual plane, were prepared for histological analysis. The analysis was evaluated clinically and histometrically. Results: The untreated implants and $H_2O_2$-swabbed implants showed gingival inflammation. Only the saline-swabbed implant group showed re-osseointegration and no gingival inflammation. There was no difference in regeneration height or bone-to-implant contact between in situ implant placement and implant placement in the new bone site. Conclusions: It can be concluded that cleaning with saline may be effective in implant decontamination. After implant surface decontamination, implant installation in a previous peri-implant diseased site may not interfere with osseointegration.