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Photochemistry and Photobiology

Yang Liu, Jia Liu, Yu Wang, Ann Abozeid, Dong-Mei Tian, Xiao-Ning Zhang, Zhong-Hua Tang
In this work, the changes in isoflavone levels and the expression of genes involved in their biosynthesis were studied in two Astragalus by UPLC-MS and real-time PCR after 10 days of UV-B treatment (λmax = 313 nm, 804 J/ m(2) ). Isoflavones were significantly induced by UV-B irradiation. The influence might be activated by the regulation of these target genes. Our results indicate that (1) the resistance of A. membranaceus might not be as good as A. mongholicus in the enhanced UV-B radiation environment; (2) the enhanced accumulation of Calycosin and Calycosin-7-glucoside with UV-B treatment in roots of A...
September 7, 2017: Photochemistry and Photobiology
Dan Zhang, Taotao Ji, Jingang Yu, Xinyu Jiang, Feipeng Jiao
A novel Cs0.33 WO3 /LDHs (CWLDH) composite was synthesized by simple two steps solvothermal method and first investigated as the photocatalyst for tetracycline (TC) and Congo red (CR) degradation under visible light irradiation. The CWLDH heterostructures catalysts were characterized by XRD, UV-vis, SEM, XPS and BET. The composite CWLDH showed enhanced photocatalytic activity compared with pure Cs0.33 WO3 and NiAl-LDH under identical experimental conditions. The enhanced photocatalytic activity was mainly attributed to the higher visible-light adsorbing ability, efficient electron-hole separation, and prolonged lifetimes of photogenerated charges...
September 7, 2017: Photochemistry and Photobiology
Jiacheng Yi, Hua Fang
The first excited-state proton transfer (ESPT) in 7AI-H2 O complex and its derivatives, in which the hydrogen atom at the C2 position in pyrrole ring was replaced by halogen atom X (X=F, Cl, Br), were studied at the TD-M06-2X/6-31+G(d, p) level. The double proton transfer took place in a concerted but asynchronous protolysis pathway. The vibrational-mode selectivity of excited-state double proton transfer in the model system was confirmed. The specific vibrational-mode could shorten the reaction path and accelerate the reaction rate...
September 7, 2017: Photochemistry and Photobiology
Elaine Sciuniti Benites Mansano, Gutierrez Rodriguês de Morais, Edilaine Martins Moratto, Francielle Sato, Mauro Luciano Baesso, Antonio Neto Medina, Terezinha Inez Estivalet Svidzinski, Luzmarina Hernandes
Paracoccidioides brasiliensis (Pb) can disseminate through the lymphatic and hematogenic pathways. As a result the spleen and other lymphoid organs are targets of paracoccidioidomycosis. There are few studies describing this disease in the spleen and more detailed descriptions are required. The present study combines Histopathology and Fourier Transform Raman Spectroscopy (FT-Raman) methods to study spleen infected by Pb. The Swiss mice were euthanized after one, two, four and eight weeks of infection with Pb and their spleens were removed for ex vivo analyzes...
September 7, 2017: Photochemistry and Photobiology
Shuwei Ning, Qiaozhen Kang, Dandan Fan, Jingjing Liu, Chaoyue Xue, Xiaolin Zhang, Cong Ding, Jianying Zhang, Qian Peng, Zhenyu Ji
5-aminolevulinic acid (5-ALA)-based photodynamic therapy (PDT) has been successfully used in the treatment of cancers. However, the mechanism of 5-ALA transportation into cancer cells is still not fully elucidated. Previous studies have confirmed that the efficiency of 5-ALA-PDT could be affected by the membrane skeleton protein 4.1R. In this study we investigated the role of 4.1R in the transport of 5-ALA into cells. Wild-type (4.1R(+/+) ) and 4.1R gene knockout (4.1R(-/-) ) mouse embryonic fibroblast (MEF) cells were incubated with 1 mM 5-ALA and different concentrations of specific inhibitors of GABA transporters GAT(1-3)...
September 7, 2017: Photochemistry and Photobiology
Oscar Juan Oppezzo, Ana Florencia Forte Giacobone
Persister bacteria tolerate bactericidal antibiotics due to transient and reversible phenotypic changes. Since these bacteria can limit the effectiveness of antibiotics to eradicate certain infections, their elimination is a relevant issue. Photodynamic therapy seems suitable for this purpose, but phenotypic tolerance to it has also been reported for Pseudomonas aeruginosa. To test whether any phenotypic feature could confer tolerance against both antibiotics and photoinactivation, survivors from exposures to light in the presence of methylene blue were treated with ofloxacin, an antibiotic effective on non-growing bacteria...
September 7, 2017: Photochemistry and Photobiology
Shosuke Ito, Kazumasa Wakamatsu, Tadeusz Sarna
Eumelanin is photoprotective for pigmented tissues while pheomelanin is phototoxic. In this review, we summarize current understanding of how eumelanin and pheomelanin structures are modified by ultraviolet A (UVA) and also by visible light and how reactive oxygen species participate in those processes. Alkaline hydrogen peroxide oxidation was employed to characterize eumelanin and benzothiazole-type pheomelanin, giving pyrrole-2,3,5-tricarboxylic acid (PTCA) and thiazole-2,4,5-tricarboxylic acid (TTCA), respectively...
September 5, 2017: Photochemistry and Photobiology
Elisabeth Ignatz, Yann Geisselbrecht, Stephan Kiontke, Lars-Oliver Essen
All light-sensitive members of the photolyase/cryptochrome family rely on FAD as catalytic cofactor. Its activity is regulated by photoreduction, a light-triggered electron transfer process from a conserved tryptophan triad to the flavin. The stability of the reduced flavin depends on available external electron donors and oxygen. In this study, we show for the class II photolyase of Methanosarcina mazei, MmCPDII, that it utilizes physiologically relevant redox cofactors NADH and NADPH for the formation of the semiquinoid FAD in a light-dependent reaction...
August 31, 2017: Photochemistry and Photobiology
Wei Gao, Pei Lin, Eunson Hwang, Yushuai Wang, Zhengfei Yan, Hien T T Ngo, Tae-Hoo Yi
Ultraviolet light-induced reactive oxygen species (ROS) damage human skin and prematurely cause aging. A growing body of research is focusing on considering plants and plant-derived compounds as anti-photoaging therapeutic material. Pterocarpus santalinus L., as an Indian traditional medicine, possesses antidiabetic, anti-inflammatory and antioxidative effects. Here, we studied the anti-photoaging effects of ethanolic extract of P. santalinus L. heartwood (EPS) on ultraviolet radiation B (UVB)-irradiated normal human dermal fibroblasts (NHDFs)...
August 31, 2017: Photochemistry and Photobiology
Hua Wang, Liefeng Liang, Xinjian Cheng, Yanmei Luo, Sheng Sun
Porous ZnS and ZnO nano-crystal films were fabricated via a three-step procedure. First, Zn(CH3 COO)2 /Silk Fibroin nanofiber mats were prepared by coaxial electrospinning. Second, Zn(CH3 COO)2 /Silk Fibroin mats were immersed in NaS solution to react with S(2-) to obtain ZnS/Silk Fibroin nanofiber mats. Finally, ZnO porous films were prepared by calcination of ZnS/Silk Fibroin composite mat at 600°C in air atmosphere. When ZnS/Silk Fibroin mats were calcinated in nitrogen, ZnS/Carbon composite mats were obtained accordingly...
August 31, 2017: Photochemistry and Photobiology
Irina Dokukina, Christel M Marian, Oliver Weingart
Polyenic systems are involved in light perception of numerous living organisms. Although a π-conjugated backbone is a common feature of all polyenes, their photophysics may vary. We provide a comparative quantum-mechanical study of low lying S1 and S2 excited states in short (3-5 double bonds) symmetric all-trans linear polyenes and corresponding protonated Schiff bases. In our investigation, we use the well-established ab initio multireference CASPT2 approach and benchmark the efficient semi-empirical OM2-MRCI approach against it...
August 22, 2017: Photochemistry and Photobiology
Vahid Mahmoodi, Ali Ahmadpour, Tahereh Rohani Bastami, Mohammad Taghi Hamed Mousavian
In this paper, highly photoactive BiOI nanoparticles (NPs) under sunlight irradiation were synthesized by a facile precipitation method using polyvinylpyrrolidone (PVP) at room temperature. The as-prepared catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) and UV-vis diffusive reflectance spectra (UV-vis DRS). The results of XRD showed that PVP did not have any significant effect on tetragonal crystalline structure of BiOI...
August 21, 2017: Photochemistry and Photobiology
Alaa El-Din Hamid Sayed
Ultraviolet-A light (UVA) -induced DNA damage and repair in red blood cells to investigate the sensitivity of African catfish to UVA exposure is reported. Fishes were irradiated with various doses of UVA light (15, 30, and 60 min/day for 3 days). Morphological and nuclear abnormalities in red blood cells were observed in the fish exposed to UVA compared with controls. Morphological alterations such as acanthocytes, crenated cells, swollen cells, teardrop-like cells, hemolyzed cells, and sickle cells were observed...
August 2, 2017: Photochemistry and Photobiology
Alicja Utrata-Wesołek, Iwona Żymełka-Miara, Agnieszka Kowalczuk, Barbara Trzebicka, Andrzej Dworak
Hydrogels of biologically well-tolerated, high-molar-mass polyglycidol and its thermoresponsive derivative poly(glycidol-co-ethyl glycidyl carbamate) have been obtained by direct UV crosslinking in the solid state. Polymers with molar masses up to 1.45 x 10(6) g/mol were crosslinked in the presence of benzophenone or (4-benzoylbenzyl)trimethylammonium chloride as photosensitizers. The photosensitizer concentration was varied from 2 to 10 wt%. The influence of polymer composition and photosensitizer type and amount on the crosslinking efficiency, swelling and temperature behavior of the obtained hydrogels was investigated...
August 2, 2017: Photochemistry and Photobiology
Cheryl Leong, Paul L Bigliardi, Gopu Sriram, Bijin Veonice Au, John Connolly, Mei Bigliardi-Qi
Phototherapy is routinely used for the treatment of various skin conditions and targeted therapy of superficial cancers. However, the molecular mechanisms behind their biological effects and the need for efficacy enhancing photosensitizers are not well addressed. Particularly, not much is known about the inherent effect of light from the visible spectrum on cytokine release and its downstream effects in keratinocytes and immune cells located in skin and therefore exposed to light. To address this, we delivered calibrated doses of well-defined light qualities (380 to 660 nm) to co-cultures of human keratinocytes and macrophage/dendritic cells in the absence or presence of the commonly used photosensitizer 8-methoxypsoralen (8-MOP)...
August 1, 2017: Photochemistry and Photobiology
Heng Zhang, Shupeng Liu, Xiangfei Yang, Na Chen, Fufei Pang, Zhenyi Chen, Tingyun Wang, Jianshe Zhou, Fuji Ren, Xiaoyin Xu, Taihao Li
Tiny but highly efficient, a light emitting diode (LED) can power a therapy device, such as a phototherapy device, and, at the same time, decrease the device's size requirements. In this study, a LED phototherapy device was designed to investigate the possible impact on wound healing using a mouse model and a cell line exposed to red and blue light. To enhance wound phototherapy, a gelatin sponge was fabricated. Results showed that the red and blue lights promoted cell growth and wound healing, while the blue light with a gelatin sponge protected the wound from infection in the early stages of wound healing...
August 1, 2017: Photochemistry and Photobiology
Paulo Vale
The chain-forming dinoflagellate Gymnodinium catenatum was exposed to hydrogen peroxide. Microscopical examination revealed striking dose-response alterations in chain formation above 245 μM: singlets replaced the dominance of long chain formations. These observations were valid for cells acclimated to halogen light. Under fluorescent light, cells were more resistant to modifications in chain length after H2 O2 exposure. Growth along 9-hour in the presence of extracelular H2 O2 followed an hormesis response in both light regimes...
August 1, 2017: Photochemistry and Photobiology
Caroline S Cencer, Shravan K Chintala, Tenira J Townsend, Daniel P Feldmann, Mirna A Awrow, Nahrain A Putris, Mason E Geno, Maria G Donovan, Frank J Giblin
This study investigated poly (ADP-ribose) polymerase-1 (PARP-1) activation in cultured human lens epithelial cells exposed to two levels of UVB light (312 nm peak wavelength), 0.014 and 0.14 J/cm(2) ("low" and "high" dose, respectively). At the low dose, PARP-1 and poly (ADP-ribose) (PAR) polymers acted to repair DNA strand breaks rapidly with no subsequent major effects on either cell morphology or viability. However, following the high UVB dose, there was a dramatic second phase of PARP-1 activation, 90 min later, which included a sudden reappearance of DNA strand breaks, bursts of reactive oxygen species (ROS) formation both within the mitochondria and nucleus, a translocation of PAR from the nucleus to the mitochondria, and an ultimate 70% loss of cell viability occurring after 24 hrs...
July 30, 2017: Photochemistry and Photobiology
Jiawan Wang, Meili Guo, Yonghua Li, Ronghua Wu, Kaiming Zhang
Begonia semperflorens is an ornamental perennial herb. The leaves of B. semperflorens turn red under increased light, which increases the ornamental value of the plant. The color of the leaves is determined by anthocyanin metabolism. In B. semperflorens leaves, anthocyanin metabolism is sensitive to external environmental conditions such as temperature, light and hormone levels. To explore this process in detail and to assess gene expression under high light stress, transcriptome analysis was performed by RNA sequencing using the sequencing-by-synthesis method...
July 26, 2017: Photochemistry and Photobiology
Marija Najdanova, Daniel Gräsing, A Alia, Jörg Matysik
The origin of the functional symmetry break in bacterial photosynthesis challenges since several decades. Although structurally very similar, the two branches of cofactors in the reaction center (RC) protein complex act very differently. Upon photochemical excitation, an electron is transported along one branch, while the other remains inactive. Photochemically induced dynamic nuclear polarization (photo-CIDNP) magic-angle spinning (MAS) (13) C NMR revealed that the two bacteriochlorophyll cofactors forming the "Special Pair" donor dimer are already well distinguished in the electronic ground-state...
July 26, 2017: Photochemistry and Photobiology
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