• Rapid Communication in Photoscience
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• 제4권2호
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• pp.37-40
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• 2015

To examine the photosensitized biomolecules damaging activity, dimethoxyP(V)tetrakis(2-naphthyl)porphyrin (NP) and dimethoxyP(V)tetraphenylporphyrin (PP) were synthesized. The naphthyl moiety of NP hardly deactivated the photoexcited P(V)porphyrin ring in ethanol. In aqueous solution, the naphthyl moiety showed the quenching effect on the photoexcited porphyrin ring, possibly through electron transfer and self-quenching by a molecular association. Binding interaction between human serum albumin (HSA), a water soluble protein, and these porphyrins could be confirmed by the absorption spectral change. The apparent association constant of NP was larger than that of PP. It is explained by that more hydrophobic NP can easily bind into the hydrophobic pockets of HSA. The photoexcited PP effectively induced damage of the tryptophan residue of HSA, through electron transfer-mediated oxidation and singlet oxygen generation. NP also induced HSA damage during photo-irradiation and the contributions of the electron transfer and singlet oxygen mechanisms were speculated. The electron transfer-mediated mechanism to the photosensitized protein damage should be advantageous for photodynamic therapy in hypoxic condition. The quantum yield of the HSA photodamage by PP was significantly larger than that of NP. The quenching effect of the naphthyl moiety is considered to suppress the photosensitized protein damage. In conclusion, the naphthalene substitution to the P(V)porphyrins can enhance the binding interaction with hydrophobic biomacromolecules such as protein, however, this substitution may reduce the photodynamic effect of P(V)porphyrin ring in aqueous media.

• Journal of Ginseng Research
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• 제14권1호
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• pp.57-62
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• 1990

In order to Investigate the mechanism of the leaf-burning disease of ginseng (Panax ginseng C.A. Meyer), studies on the generation of singlet oxygen (1O2) and the photooxidation of the pigments were carried out in comparison with the ones of soybean (G1ycine max L). The studies were mainly focalized on the effects of light intensity, light intensity, inhibitor and electron donor/acceptor of the Photosynthetic electron transport system. When we measured the amounts of 1O2 generated in the thylakoids of ginseng and soybean by the irradiation of light (300 w/m2) as a function its time. It was identified that a higher amount of 1O2 was formed in the ginseng thylakoid than the case of soybean. A generation ratio of lO2 between ginseng and soybean sltbstantially identical in the range of light intensities 50∼150w/m2 However much higher amount of 1O2 was generated in ginseng by irradiation of strong intensity of light (200 500w/m2). Wave length dependency on the generation of 1O2 and the pigment photooxidation was observed on ginseng thylakoids; red light (600-700 nm) gave a maximum effect in the contrast with blur green light (400-60 nm). When the ginseng thylalioid was treated with the electron donor (Mn2+) and acceptors (DCPIP, FeCy) of the photosynthetic electron transport system. a drastic inhibition of 1O2 generation was observed. However, treatment with its inhibitors (DCMU, KCW) activated 1O2 generation. An interesting fact that an electron donor or acceptor of the photosystem II(P680) Inhibited 1O2 generation, suggests an intimate relationship between 1O2 generation and photosystem II.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.70-71
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• 2003

산소-요오드 화학레이저(Chemical Oxygen iodine Laser： COIL)는 화학반응에 의해 발생되는 막대한 에너지를 변환시켜 레이저발진을 일으키는 기술로서 화학반응물의 양에 비례하여 출력을 높일 수 있어서 MW급 이상의 고출력이 가능한 레이저이다. 화학반응에 의해 레이저빔이 발생되는 COIL은 화학반응량에 비례하여 높은 화학에너지를 발생시키게 되며, 빛 에너지로 변환되어 고출력레이저가 가능해 진다. (중략)

• Bulletin of the Korean Chemical Society
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• 제7권2호
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• pp.150-153
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• 1986

Co-sensitized photooxygenation of 1,1-diphenyl-2-vinylcyclopropane (VCP-DPh) with 9,10-dicyanoanthracene and biphenyl in oxygen-saturated acetonitrile solution produced 3,3-diphenyl-5-vinyl-1,2-dioxolane as the major product. The same photoproduct was obtained by acetone sensitized photooxygenation in oxygen-saturated acetone solution. However, VCP-DPh remained intact when directly irradiated with DCA or irradiated with Rose Bengal to generate singlet oxygen. A mechanism involving a cosensitizer radical cation and sensitizer radical anion is proposed.

• Journal of Ginseng Research
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• 제13권2호
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• pp.158-164
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• 1989

인삼엽소병(leaf-burning disease) 원인과 light-harvesting chlorophyll-protein(LHCP) complex의 solar energy 분배능력과의 상호 연관성을 조사하기 위한 기초 연구로써 인삼 thylakoid의 chlorophyll-protein(CP) complex의 조성 및 특징을 조사하였다. 인삼의 CP-complex는 non-denaturing SDS-PAGE 방법에 의해 4개 bands로 분리되었으며 각 band는 Bassi와 Dunahay의 결과에 따라 CPI(PSI의 reaction center와 LHCP I antennae), CP I(PSI reaction center), LHCP II(LHCP II)의 oligoform), 그리고 LHCP II(PS II antennae; CP29, CP26)로 확인되었다. 인삼의 LHCP II 는 양지식물인 spinach, soybean과 비교해 볼 때 오히려 인삼의 band intensity가 더 높았으며, CP I band는 인삼에서만 분리되었다. 인삼 CP-complex band의 absorption 및 fluorescence spectra, chlorophyll a.b ratio 에서도 비교식물과 차이를 나타내었다. Thylakoid membrane의 polypeptide 함량은 인삼에서 비교식물에 비해 현저히 낮은 polypeptide 함량은을 나타내었다. SDS-PAGE에 의한 polypeptide pattern은 band의 수나 band intensity에서 비교식물과 차이를 나타내었으며, 특히 29-35 kD, 55 kD과 60 kD 근치에서 현저한 band intensity 차이를 확인하였다. Specific $^1O_2$에 의해 chl. a가 60%, chl.b는 90%, 그리고 carotenoid는 70%가 파괴되는 것으로 확인되었다.

• 한국환경과학회지
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• 제25권3호
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• pp.373-383
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• 2016

The aim of this study is to determine the exposure concentration of tetrabromobisphenol A(TBBPA) in southwestern coast and their photodecomposition rate. Also, it is to identify the radical species of the photodecomposition of TBBPA and their reactive byproducts using the electron spin resonance(ESR) method. TBBPA was not detected in any of the sea water samples from Mokpo, Gunsan, or Goheung. The sediment samples from Mokpo contained not detection(N.D)~50.0 ng/g dry wt., while those from Gunsan contained N.D~28.5 ng/g dry wt. and those from Goheung contained N.D~7.3 ng/g dry wt. The photodecomposition rates were $2.56{\times}10^{-6}/hr$ by visible light(400 nm), $7.98{\times}10^{-6}/hr$ by ultraviolet light(300 nm <), and $6.78{\times}10^{-6}/hr$ by sunlight. Also, we confirmed that singlet oxygen and hydroxyl radicals are the key reactive oxygen species at wavelengths greater than 400 and 300 nm, respectively. This study shows that the main byproducts formed during irradiation at wavelengths above 300 nm are 2,6-dibromobenzosemiquinone radical(2,6-$DBSQ{\cdot}^-$) and g-value 2.0048 doublet spectrum.

• Plant Biotechnology Reports
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• 제2권1호
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• pp.21-31
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• 2008

In plants, the oxygen generated by photosynthesis can be excited to form reactive oxygen species (ROS) under excessive sunlight. Excess ROS including singlet oxygen ($^1O_2$) inhibit the growth, development and photosynthesis of plants. To isolate ROS-resistant crop plants, we used paraquat (PQ), a generator of $O_2{^-}$ as a source of screening and mutagen, and obtained two PQ-resistant lines in Pisum sativum, namely R3-1 and R3-2. Both lines showed greater resistance to PQ than their wild type (WT) siblings with respect to germination, root growth, and shoot growth. Biochemical analysis showed differences in these lines, in which ROS-scavenging enzymes undergo changes with a distinguishable increase in Mn-SOD. We further observed that the cytosolic catalases (CATs) in leaves in both lines were shifted in a native-PAGE analysis compared with that of the WT, indicating that the release of bound $^1O_2$ was enhanced. Phenotypic analysis revealed distinguishable differences in leaf development, and in flowering time and position. In addition, R3-1 and R3-2 showed shorter individual inter-node lengths, dwarf plant height, and stronger branching compared with the WT. These results suggested that PQ-induced ROS-resistant Pisum have the potential pleiotropic effects on flowering time and stem branching, and that ROS including $^1O_2$ plays not only important roles in plant growth and development as a signal transducer, but also appears as a strong inhibitor for crop yield.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2006년도 International Meeting of the Microbiological Society of Korea
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• pp.63-65
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• 2006

• 약학회지
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• 제44권1호
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• pp.36-40
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• 2000

The photodegradation of pefloxacin, photolabile fluoroquinolone antibacterial agent, was studied. In the presence of $N_2$, photodegradation of pefloxacin was suppressed. The singlet oxygen and free radical generated in the reaction media proceeded photochemical reaction. The photodegradation of peflxacin was sensitized by benzophenone, a triplet state sensitizer.

• 한국광과학회:학술대회논문집
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• 한국광과학회 2002년도 정기총회 및 제9회 광과학 학술심포지움 논문초록
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• pp.66-66
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• 2002