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Photochemistry and Photobiology

Lu Yang, Fangyun Ye, Peng Liu, Fazhou Wang
Visible light driven Ag/AgBr/TiO2 /activated carbon (AC) composite was prepared by sol-gel method coupled with photo-reduction method. For comparison, TiO2 , TiO2 /AC and Ag/AgBr/TiO2 were also synthesized. Their characteristics were analyzed by XRD, SEM-EDS, TG-DSC and UV-Vis techniques. Photocatalytic activity and antibacterial performance under visible light irradiation were investigated by ICP-AES, ATR-FT-IR and spectrophotometry methods using methylene blue and Escherichia coli as target systems, respectively...
October 20, 2016: Photochemistry and Photobiology
Bice S Martincigh, Moses A Ollengo
The photostabilizing ability of grape seed extract on three common sunscreen absorbers: 2-ethylhexyl-p-methoxcinnamate (EHMC), benzophenone-3 (BP3) and tert-butylmethoxy dibenzoylmethane (BMDBM), was investigated. Samples were exposed to simulated solar radiation and monitored by spectrophotometric and chromatographic methods. The chemical composition of the grape seed extract was determined by GC-MS and HPLC-MS and the major secondary metabolites were found to be epicatechin and catechin. Exposure of the extract to UV radiation increased the UV absorption capacity of the extract...
October 19, 2016: Photochemistry and Photobiology
Masaatsu Miyauchi, Hideaki Nakajima
UV radiation contains erythemally-weighted UV, as well as UV that synthesizes vitamin D3 . Here, we attempted to determine the relationship between these factors by numerical simulation of atmospheric parameters, such as total ozone, using a simplified "SMART2″ model for radiative transfer. Both forms of UV were almost linearly correlated with each other for a comparably large UV radiation exposure, larger than UV Index ~ 1.6. If erythemally-weighted UV, which carries a risk of sunburn, is known, the amount of UV exposure needed for vitamin D synthesis in the epidermis can be estimated using this relationship...
October 18, 2016: Photochemistry and Photobiology
John Lee
The molecular mechanisms of the bioluminescence systems of the firefly, bacteria, and those utilizing imidazopyrazinone luciferins such as coelenterazine, are gradually being uncovered using modern biophysical methods such as dynamic (ns-ps) fluorescence spectroscopy, NMR, X-ray crystallography, and computational chemistry. The chemical structures of all reactants are well defined and the spatial structures of the luciferases are providing important insight into interactions within the active cavity. It is generally accepted that the firefly and coelenterazine systems, although proceeding by different chemistries, both generate a dioxetanone high energy species that undergoes decarboxylation to form directly the product in its S1 state, the bioluminescence emitter...
October 17, 2016: Photochemistry and Photobiology
Qianzheng Zhu, Altaf A Wani
Nucleotide excision repair (NER) eliminates a broad variety of helix-distorting DNA lesions that can otherwise cause genomic instability. NER comprises two distinct sub-pathways: global genomic NER (GG-NER) operating throughout the genome, and transcription-coupled NER (TC-NER) preferentially removing DNA lesions from transcribing DNA strands of transcriptionally active genes. Several NER factors undergo post-translational modifications, including ubiquitination, occurring swiftly and reversibly at DNA lesion sites...
October 1, 2016: Photochemistry and Photobiology
Bruce R Branchini, Tara L Southworth, Leah J Salituro, Danielle M Fontaine, Yuichi Oba
In the southern Appalachian area of the United States, the Phausis reticulata firefly, commonly known as the "Blue Ghost," performs a unique display of bioluminescence. Adult male organisms are observed darting rapidly along paths and riverbeds in dark forests producing long-lasting and mesmerizing bluish-white luminous streaks. Starting with eighteen adult male firefly lanterns, we used a reverse transcriptase and rapid amplification of cDNA ends (RACE) approach to clone the 1635 base pair open reading frame of the P...
October 1, 2016: Photochemistry and Photobiology
Eugenia E Bashmakova, Vasilisa V Krasitskaya, Alexander N Kudryavtsev, Vitaly G Grigorenko, Ludmila A Frank
Ca(2+) -regulated photoprotein obelin was genetically fused with a minimum-sized core streptavidin. Hybrid protein (SAV-OL) was produced by bacterial expression and applied as a specific bioluminescent probe in diverse solid-phase assays. The obtained results clearly demonstrate specific activity of each domain indicating its proper folding with favorable space orientation. SAV-OL has been shown to be a much more sensitive label than the chemical conjugate of a full-length streptavidin with obelin. This article is protected by copyright...
October 1, 2016: Photochemistry and Photobiology
Peng Mao, John J Wyrick, Steven A Roberts, Michael J Smerdon
UV radiation induces photolesions that distort the DNA double helix and, if not repaired, can cause severe biological consequences, including mutagenesis or cell death. In eukaryotes, both the formation and repair of UV damage occur in the context of chromatin, in which genomic DNA is packaged with histones into nucleosomes and higher-order chromatin structures. Here, we review how chromatin impacts the formation of UV photoproducts in eukaryotic cells. We describe the initial discovery that nucleosomes and other DNA-binding proteins induce characteristic 'photofootprints' during the formation of UV photoproducts...
September 26, 2016: Photochemistry and Photobiology
Cezary Skobowiat, Arnold E Postlethwaite, Andrzej T Slominski
The back skin of C57BL/6 mice was exposed to a single 400 mJ/cm(2) dose of ultraviolet B (UVB), and parameters of hypothalamic-pituitary-adrenal (HPA) axis in relation to immune activity were tested after 30-90 min following irradiation. Levels of brain and/or plasma corticotropin releasing hormone (CRH), β-endorphin, ACTH and corticosterone (CORT) were enhanced by UVB. Hypophysectomy had no effect on UVB-induced increases of CORT. Mitogen induced IFNγ production by splenocytes from UVB-treated mice was inhibited at 30, 90 min and after 24 h...
September 26, 2016: Photochemistry and Photobiology
Andrea Amaroli, Alberico Benedicenti, Sara Ferrando, Steven Parker, Wayne Selting, Lorenzo Gallus, Stefano Benedicenti
In Paramecium cilia beating is correlated to intracellular calcium concentration ([Ca(2+) ]i) and nitric oxide (NO) synthesis. Recent findings affirm that photobiomodulation (PBM) can transiently increase the [Ca(2+) ]i in mammalian cells. In the present study we investigated the effect of both 808nm and 980nm diode laser irradiated with flat-top hand-piece on [Ca(2+) ]i and NO production of Paramecium primaurelia, to provide basic information for the development of new therapeutic approaches. In the experiments, the laser power in CW varied (0...
September 26, 2016: Photochemistry and Photobiology
Yasuo Mitani, Ryo Futahashi, Zichao Liu, Xingcai Liang, Yoshihiro Ohmiya
Fireflies are widespread all over the world and a numerous numbers of luciferases have been isolated and characterized. In this study, we identified and characterized the luciferase and luciferase-like genes from a Tibetan firefly collected in Shangri-La, China. The altitude of this area is more than 3,300 meters. We saw this Tibetan firefly flying with strong luminescence after sunset at ~10°C. We analyzed the transcriptome of Tibetan firefly using head, thorax, abdomen (without light organ), and light organ tissue by RNA sequencing...
September 26, 2016: Photochemistry and Photobiology
Camila Fabiano de Freitas, Diogo Silva Pellosi, Bianca Martins Estevão, Italo Rodrigo Calori, Tayana Mazin Tsubone, Mário José Politi, Wilker Caetano, Noboru Hioka
It was evaluated the properties of the xanthene dyes Erythrosin B, Eosin Y and theirs Methyl, Butyl and Decyl ester derivatives as possible photosensitizers (PS) for photodynamic treatments. The more hydrophobic dyes self-aggregate in water/ethanol solutions above 70% water (v/v) in the mixture. In buffered water these PS were encapsulated in Pluronic polymeric surfactants of P-123 and F-127 by two methodologies: direct addition and the thin-film solid dispersion methods. The thin solid method provided formulations with higher stabilities besides effective encapsulation of the PS as monomers...
September 26, 2016: Photochemistry and Photobiology
Michael G Kemp, Jinchuan Hu
The nucleotide excision repair system removes a wide variety of DNA lesions from the human genome, including photoproducts induced by ultraviolet (UV) wavelengths of sunlight. A defining feature of nucleotide excision repair is its dual incision mechanism, in which two nucleolytic incision events on the damaged strand of DNA at sites bracketing the lesion generate a damage-containing DNA oligonucleotide and a single-stranded DNA gap approximately 30 nucleotides in length. Although the early events of nucleotide excision repair, which include lesion recognition and the dual incisions, have been explored in detail and are reasonably well understood, the fate of the single-stranded gaps and excised oligonucleotide products of repair have not been as extensively examined...
September 19, 2016: Photochemistry and Photobiology
Stuart G Jarrett, John A D'Orazio
Melanoma is the deadliest form of skin cancer because of its propensity to spread beyond the primary site of disease and because it resists many forms of treatment. Incidence of melanoma has been increasing for decades. Though ultraviolet radiation (UV) has been identified as the most important environmental causative factor for melanoma development, UV-protective strategies have had limited efficacy in melanoma prevention. UV mutational burden correlates with melanoma development and tumor progression, underscoring the importance of UV in melanomagenesis...
September 19, 2016: Photochemistry and Photobiology
Nadezhda S Kudryasheva, Ekaterina S Kovel, Anna S Sachkova, Anna A Vorobeva, Viktoriya G Isakova, Grigoriy N Churilov
A bioluminescent assay based on a system of coupled enzymatic reactions catalyzed by bacterial luciferase and NADH:FMN-oxidoreductase was developed to monitor toxicity and antioxidant activity of bioactive compounds. The assay enables studying toxic effects at the level of biomolecules and physicochemical processes, as well as determining the toxicity of general and oxidative types. Toxic and detoxifying effects of bioactive compounds were studied. Fullerenols, perspective pharmaceutical agents, nanosized particles, water-soluble polyhydroxylated fullerene-60 derivatives were chosen as bioactive compounds...
September 19, 2016: Photochemistry and Photobiology
Jimyeong Song, Michael G Kemp, Jun-Hyuk Choi
The human nucleotide excision repair system targets a wide variety of DNA adducts for removal from DNA, including photoproducts induced by UV wavelengths of sunlight. A key feature of nucleotide excision repair is its dual incision mechanism, which results in generation of a small, damage-containing oligonucleotide approximately 24- to 32-nt in length. Detection of these excised oligonucleotides using cell-free extracts and purified proteins with defined DNA substrates has provided a robust biochemical assay for excision repair activity in vitro...
September 16, 2016: Photochemistry and Photobiology
Cameron C Jones, Steffi Valdeig, Raymond M Sova, Clifford R Weiss
Biofilms are difficult to eradicate due to a protective architecture and create major challenges in patient care by diminishing both host immune response and therapeutic approaches. This study investigated a new strategy for treating surface-attached biofilms by delivering germicidal UV through a material surface in a process referred to as "inside-out sterilization" (IOS). Mature Pseudomonas aeruginosa (ATCC(®) 27853(™) ) biofilms were irradiated with up to 1400 mJ cm(-2) of germicidal UV from both ambient and IOS configurations...
September 12, 2016: Photochemistry and Photobiology
Jonathan M Fahey, Joseph V Emmer, Witold Korytowski, Neil Hogg, Albert W Girotti
Gliomas are aggressive brain tumors that are resistant to conventional chemotherapy and radiotherapy. Much of this resistance is attributed to endogenous nitric oxide (NO). Recent studies revealed that 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) has advantages over conventional treatments for glioblastoma. In this study, we used an in vitro model to assess whether NO from glioblastoma cells can interfere with ALA-PDT. Human U87 and U251 cells expressed significant basal levels of neuronal NO synthase (nNOS) and its inducible counterpart (iNOS)...
September 8, 2016: Photochemistry and Photobiology
Ilana Sherman, Yoram Gerchman, Yoel Sasson, Hani Gnayem, Hadas Mamane
This study demonstrates the potential of a new BiOCl0.875 Br0.125 photocatalyst to disinfect Escherichia coli in water under simulated solar irradiation. Photocatalytic efficiency was examined for different photocatalyst loadings, solar wavelengths, exposure times, photocatalyst concentration × contact time (Ct) concept, and with the use of scavengers. To elucidate the inactivation mechanism, we examined DNA damage, membrane damage, lipid peroxidation and protein release. Both photolysis and photocatalysis were negligible under visible irradiation, but enhanced photocatalytic activity was observed under solar UVA (λ > 320 nm) and UVB (λ > 280 nm), with 1...
August 17, 2016: Photochemistry and Photobiology
Huaping Li, Aili Gao, Na Jiang, Qing Liu, Bihua Liang, Runxiang Li, Erting Zhang, Zhenjie Li, Huilan Zhu
Ultraviolet B (UVB) irradiation is one of the most dangerous insults for skin, and causes sunburn, erythema, photoaging and photocarcinogenesis. Curcumin (diferuloylmethane), a yellow spice derived from dried rhizomes of Curcuma longa, has been shown to possess significant anti-inflammatory, anti-oxidant, anti-carcinogenic, anti-mutagenic, anticoagulant and anti-infective effects. However, the protective effects of curcumin against acute photo-damage are poorly understood. In this study, we investigated the photo-protective effects of curcumin against UVB induced acute photo-damage in hairless mice and immortalized human keratinocytes (HaCaT)...
August 12, 2016: Photochemistry and Photobiology
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