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Showing 601 - 735 of 735 Journals sorted alphabetically
World Journal of Chemical Education     Open Access   (Followers: 1)
X-Ray Spectrometry     Hybrid Journal   (Followers: 10)
Zeitschrift für Naturforschung B : A Journal of Chemical Sciences     Open Access   (Followers: 1)

  First | 1 2 3 4     

Journal Cover Photochemistry and Photobiology
  [SJR: 0.63]   [H-I: 106]   [1 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0031-8655 - ISSN (Online) 1751-1097
   Published by John Wiley and Sons Homepage  [1611 journals]
  • The Visible Light Photocatalytic Activity and Antibacterial Performance of
           Ag/AgBr/TiO2 Immobilized on Activated Carbon
    • Authors: Lu Yang; Fangyun Ye, Peng Liu, Fazhou Wang
      Abstract: 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. The results showed that Ag/AgBr was successfully deposited on anatase TiO2/AC surface, and exhibited a distinct light absorption in the visible region. Ag/AgBr/TiO2/AC displayed excellent antibacterial performance both in dark and under visible light illumination. The growth of E. coli cell was inhibited in presence of Ag/AgBr/TiO2/AC in dark. Moreover, upon visible light illumination, a significant damaged of cell membrane was noticed. Ag/AgBr/TiO2/AC was also shown higher photocatalytic efficiency for methylene blue degradation than those of TiO2, TiO2/AC and Ag/AgBr/TiO2. This is attributed to the synergetic effect between AC and Ag/AgBr/TiO2, of which AC acts as the role of increasing reaction areas, continuous enriching and transferring the adsorbed MB molecules to the surface of supported photocatalysts, and the Ag/AgBr/TiO2 acts as a highly active photocatalyst for degrading MB molecules under visible light irradiation.This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-20T03:45:23.134136-05:
      DOI: 10.1111/php.12653
  • The Photostabilizing Effect of Grape Seed Extract on Three Common
           Sunscreen Absorbers
    • Authors: Bice S. Martincigh; Moses A. Ollengo
      Abstract: 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. All sunscreens showed an improved photostability in the extract. The inherent photo-instability of BMDBM when exposed to UV radiation was almost eliminated in the presence of grape seed extract. A mixture of all three sunscreens in the extract showed very high photostability and a red shift covering the entire UVB and UVA regions thereby improving the broad-spectrum protection. The incorporation of grape seed extract in sunscreen and other cosmetic formulations for topical application boosts photoprotection by stabilizing the UV filters and enhancing broad-spectrum coverage. This in turn helps in reducing the amounts of absorbers and other additives incorporated in a sunscreen product and consequently lowers the risk of an unprecedented build-up of photoproducts whose toxicities are currently unknown.This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-19T09:35:23.252659-05:
      DOI: 10.1111/php.12652
  • Determining an Effective UV Radiation Exposure Time for Vitamin D
           Synthesis in the Skin Without Risk to Health: Simplified Estimations from
           UV Observations
    • Authors: Masaatsu Miyauchi; Hideaki Nakajima
      Abstract: 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. The production of 10 μg (400 IU) of vitamin D per day takes approximately 1/3 of the time needed to reach the Minimal Erythemal Dose (MED) for an effective skin area of 600 cm2 for skin photo type III. For an area of 1200 cm2, 1/6 of that exposure time suffices. From a UV Index that is commonly used, the risks and benefits can be evaluated using this linear relationship which will enable people to effectively manage their UV exposure and consider the risks and benefits to optimize health outcomes.This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-18T09:25:28.19068-05:0
      DOI: 10.1111/php.12651
  • Perspectives on Bioluminescence Mechanisms
    • Authors: John Lee
      Abstract: 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. More work is still needed to establish the structure of the products completely. In spite of the bacterial system receiving the most research attention, the chemical pathway for excitation remains mysterious except that it is clearly not by a decarboxylation. Both the coelenterazine and bacterial systems have in common of being able to employ “antenna proteins”, lumazine protein and the green-fluorescent protein, for tuning the color of the bioluminescence. Spatial structure information has been most valuable in informing the mechanism of the Ca2+-regulated photoproteins and the antenna protein interactions.This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-17T09:35:21.666291-05:
      DOI: 10.1111/php.12650
  • Cloning of the Blue Ghost (Phausis reticulata) Luciferase Reveals a
           Glowing Source of Green Light
    • Authors: Bruce R. Branchini; Tara L. Southworth, Leah J. Salituro, Danielle M. Fontaine, Yuichi Oba
      Abstract: 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. reticulata luc gene corresponding to a 545 residue protein. Expression of the recombinant luciferase protein in E. coli and characterization studies revealed the true color of the light emission to be green (λmax = 552 nm), strongly suggesting that the field observations result from a Purkinje shift. While the P. reticulata luciferase amino acid sequence is 74.3% identical to the North American P. pyralis luciferase, we were surprised to find that it was 88.4% and 87.7% identical to luciferases from C. ruficollis and D. axillaris both native to mainland Japan. Phylogenetic analysis confirmed the close relationship of the three enzymes that is surprising given the great distance between their natural habitats and the inability of the Japanese fireflies to produce bright bioluminescence.This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-01T10:23:59.50573-05:0
      DOI: 10.1111/php.12649
  • Hybrid Minimal Core Streptavidin-obelin as a Versatile Reporter for
           Bioluminescence-based Bioassay
    • Authors: Eugenia E. Bashmakova; Vasilisa V. Krasitskaya, Alexander N. Kudryavtsev, Vitaly G. Grigorenko, Ludmila A. Frank
      Abstract: Ca2+-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. All rights reserved.
      PubDate: 2016-10-01T10:23:57.26145-05:0
      DOI: 10.1111/php.12648
  • Nucleotide Excision Repair: Finely Tuned Molecular Orchestra of Early
           Pre-incision Events
    • Authors: Qianzheng Zhu; Altaf A. Wani
      Abstract: 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. Accumulating evidence indicates that ubiquitination not only orchestrates the spatio-temporal recruitment of key protein factors to DNA lesion sites but also the productive assembly of NER preincision complex. This review will be restricted to the latest conceptual understanding of ubiquitin-mediated regulation of initial damage sensors of NER, i.e., DDB, XPC, RNAPII and CSB. We project hypothetical NER models in which ubiquitin-specific segregase, valosin-containing protein (VCP)/p97, plays an essential role in timely extraction of the congregated DNA damage sensors to functionally facilitate the DNA lesion elimination from the genome.This article is protected by copyright. All rights reserved.
      PubDate: 2016-10-01T10:15:25.064246-05:
      DOI: 10.1111/php.12647
  • UV‐Induced DNA Damage and Mutagenesis in Chromatin
    • Authors: Peng Mao; John J. Wyrick, Steven A. Roberts, Michael J. Smerdon
      Abstract: 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. We also describe recent progress in genome‐wide methods for mapping UV damage, which echoes early biochemical studies, and highlights the role of nucleosomes and transcription factors in UV damage formation and repair at unprecedented resolution. Finally, we discuss our current understanding of how the distribution and repair of UV DNA damage influence mutagenesis in human skin cancers.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T09:00:24.412429-05:
      DOI: 10.1111/php.12646
  • Nanostructured Polymeric Micelles Carrying Xanthene Dyes for Photodynamic
    • Authors: Camila Fabiano Freitas; Diogo Silva Pellosi, Bianca Martins Estevão, Italo Rodrigo Calori, Tayana Mazin Tsubone, Mário José Politi, Wilker Caetano, Noboru Hioka
      Abstract: 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. Size measurements demonstrated that Pluronic forms self‐assembled micelles with uniform size, which present slightly negative surface potential and a spherical form detected by TEM microscopy. The ester length modulates xanthene localization in the micelle, which is deeper with the increase of the alkyl chain. Moreover, some PS is distributed into two populations: one on the corona micelle interface shell (PEO layer) and the other into the core (PPO region). Although all PS formulations show high singlet oxygen quantum yield, promising results were obtained for Erythrosin B esters with the hydrophobic P‐123, which ensures their potential as drug for clinical photodynamic applications.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T08:55:36.692863-05:
      DOI: 10.1111/php.12645
  • Photobiomodulation by Infrared Diode‐Laser: Effects on Intracellular
           Calcium Concentration and Nitric Oxide Production of Paramecium
    • Authors: Andrea Amaroli; Alberico Benedicenti, Sara Ferrando, Steven Parker, Wayne Selting, Lorenzo Gallus, Stefano Benedicenti
      Abstract: In Paramecium cilia beating is correlated to intracellular calcium concentration ([Ca2+]i) and nitric oxide (NO) synthesis. Recent findings affirm that photobiomodulation (PBM) can transiently increase the [Ca2+]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 [Ca2+]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 (0.1W; 0.5W; 1W; 1.5W) to generate the following respective fluences: 6.4J/cm2; 32J/cm2; 64J/cm2; 96J/cm2. The 6.4J/cm2 didn't induce PBM if irradiated by both 808nm and 980nm diode laser. Conversely, the 32J/cm2 fluence had no effect on Paramecium cells if irradiated by the 808nm laser, while if irradiated by the 980 nm laser induced increment in swimming speed (suggesting an effect on the [Ca2+]i, NO production, similar to the 64J/cm2 with the 808nm wavelength). The more evident discordance occurred with the 96J/cm2fluence, which had the more efficient effect on PBM among the parameters if irradiated with the 808nm laser and killed the Paramecium cells if irradiated by the 980nm laser. Lastly, the 980nm and 64J/cm2 or 96J/cm2 were the only parameters to induce a release of stored calcium.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T08:50:29.612682-05:
      DOI: 10.1111/php.12644
  • Tibetan Firefly Luciferase With Low Temperature Adaptation
    • Authors: Yasuo Mitani; Ryo Futahashi, Zichao Liu, Xingcai Liang, Yoshihiro Ohmiya
      Abstract: 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. We identified one luciferase gene, which was almost identical to luciferase from fireflies Pyrocoelia species, and expressed specifically in the light organ. Interestingly, the optimal temperature of the Tibetan firefly recombinant luciferase was 10°C. The Km for D‐luciferin and ATP of the recombinant luciferase was 23 and 154 μM, respectively. The optimal pH was around 7.0 to 7.5. The emission peak was 556 nm at pH 8.0, while it shifted to 606 nm at pH 6.0. We also found a luciferase‐like gene with 43% identical amino acids to the Tibetan firefly luciferase, which was scarcely expressed in any portion of the adult body. No luciferase activity was detected for this luciferase‐like protein.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T08:50:23.110213-05:
      DOI: 10.1111/php.12643
  • Skin Exposure to Ultraviolet B Rapidly Activates Systemic Neuroendocrine
           and Immunosuppressive Responses
    • Authors: Cezary Skobowiat; Arnold E. Postlethwaite, Andrzej T. Slominski
      Abstract: The back skin of C57BL/6 mice was exposed to a single 400 mJ/cm2 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. UVB also led to inhibition of IL‐10 production indicating an immunosuppressive effect on both Th1 and Th2 cytokines. Conditioned media from splenocytes isolated from UVB‐treated animals had no effect on IFNγ production in cultured normal splenocytes, however IFNγ increased with conditioned media from sham‐irradiated animals. Sera from UVB‐treated mice suppressed T cell mitogen‐induced IFNγ production as compared to sera from sham‐treated mice. IFNγ production was inhibited in splenocytes isolated from UVB‐treated animals with intact pituitary, while stimulated in splenocytes from UVB‐treated hypophysectomised mice. Thus, cutaneous exposure to UVB rapidly stimulates systemic CRH, ACTH, β‐endorphin, and CORT production accompanied by rapid immunosuppressive effects in splenocytes that appear to be independent of the HPA axis.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-26T08:45:23.154824-05:
      DOI: 10.1111/php.12642
  • Post‐excision Events in Human Nucleotide Excision Repair
    • Authors: Michael G. Kemp; Jinchuan Hu
      Abstract: 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. In this review, recent findings that address these less‐explored aspects of nucleotide excision repair are discussed and support the concept that post‐incision gap and excised oligonucleotide processing are critical steps in the cellular response to DNA damage induced by UV light and other environmental carcinogens. Defects in these latter stages of repair lead to cell death and other DNA damage signaling responses and may therefore contribute to a number of human disease states associated with exposure to UV wavelengths of sunlight, including skin cancer, aging, and autoimmunity.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-19T19:25:23.282486-05:
      DOI: 10.1111/php.12641
  • Hormonal Regulation of the Repair of UV Photoproducts in Melanocytes by
           the Melanocortin Signaling Axis
    • Authors: Stuart G. Jarrett; John A. D'Orazio
      Abstract: 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. However, besides amount of UV exposure, melanocyte UV mutational load is influenced by the robustness of nucleotide excision repair, the genome maintenance pathway charged with removing UV photoproducts before they cause permanent mutations in the genome. In this review, we highlight the importance of the melanocortin hormonal signaling axis on regulating efficiency of nucleotide excision repair in melanocytes. By understanding the molecular mechanisms by which nucleotide excision repair can be increased, it may be possible to prevent many cases of melanoma by reducing UV mutational burden over time.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-19T19:25:20.826358-05:
      DOI: 10.1111/php.12640
  • Bioluminescent Enzymatic Assay as a Tool for Studying Antioxidant Activity
           and Toxicity of Bioactive Compounds
    • Authors: Nadezhda S. Kudryasheva; Ekaterina S. Kovel, Anna S. Sachkova, Anna A. Vorobeva, Viktoriya G. Isakova, Grigoriy N. Churilov
      Abstract: 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. Two homologous fullerenols with different number and type of substituents, C60O2‐4(OH)20‐24 and Fe0.5C60(OH)xOy (x+y=40‐42), were used. They suppressed bioluminescent intensity at concentrations > 0.01 g L−1 and > 0.001 g L−1 for C60O2‐4(OH)20‐24 and Fe0.5C60(OH)xOy, respectively, hence, a lower toxicity of C60O2‐4(OH)20‐24 was demonstrated. Antioxidant activity of fullerenols was studied in model solutions of organic and inorganic oxidizers; changes in toxicities of general and oxidative type were determined; detoxification coefficients were calculated. Fullerenol C60O2‐4(OH)20‐24 revealed higher antioxidant ability at concentrations 10‐17‐10‐5 g L−1. The difference in the toxicity and antioxidant activity of fullerenols was explained through their electron donor/acceptor properties and different catalytic activity. Principles of bioluminescent enzyme assay application for evaluating the toxic effect and antioxidant activity of bioactive compounds were summarized.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-19T19:20:27.241649-05:
      DOI: 10.1111/php.12639
  • Detection of the Excised, Damage‐containing Oligonucleotide Products of
           Nucleotide Excision Repair in Human Cells
    • Authors: Jimyeong Song; Michael G. Kemp, Jun‐Hyuk Choi
      Abstract: 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. However, the relevance of a number of in vitro findings to excision repair in living cells in vivo has remained unresolved. Over the past few years, novel methods for detecting and isolating the excised oligonucleotide products of repair in vivo have therefore been developed. Here we provide a basic outline of a sensitive and versatile in vivo excision assay and discuss how the assay both confirms previous in vitro findings and offers a number of advantages over existing cell‐based DNA repair assays. Thus, the in vivo excision assay offers a powerful tool for readily monitoring the repair of DNA lesions induced by a large number of environmental carcinogens and anti‐cancer compounds.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-16T02:30:41.787955-05:
      DOI: 10.1111/php.12638
  • Inside‐Out Ultraviolet‐C Sterilization of Pseudomonas
           aeruginosa Biofilm In Vitro
    • Authors: Cameron C Jones; Steffi Valdeig, Raymond M Sova, Clifford R Weiss
      Abstract: 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. The lethal dose for the ambient exposure group was 461 mJ cm−2 95% CI [292, 728] compared to the IOS treatment group of 247 mJ cm−2 95% CI [187, 325], corresponding to 47% less UV dosage for the IOS group (p < 0.05). This study demonstrated that with IOS, a lower quantal dosage of UV energy is required to eradicate biofilm than with ambient exposure by leveraging the organizational structure of the biofilm.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-12T05:00:58.784369-05:
      DOI: 10.1111/php.12637
  • Antagonistic Effects of Endogenous Nitric Oxide in a Glioblastoma
           Photodynamic Therapy Model
    • Authors: Jonathan M. Fahey; Joseph V. Emmer, Witold Korytowski, Neil Hogg, Albert W. Girotti
      Abstract: 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 the present 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). After an ALA/light challenge, iNOS level increased 3‐4 fold over 24 h, whereas nNOS remained unchanged. Elevated iNOS resulted in a large increase in intracellular NO. Extent of ALA/light‐induced apoptosis increased substantially when an iNOS inhibitor or NO scavenger was present, implying that iNOS/NO was acting cytoprotectively. Moreover, cells surviving a photochallenge exhibited a striking increase in proliferation, migration, and invasion rates, iNOS/NO again playing a dominant role. Also observed was a large iNOS/NO‐dependent increase in matrix metalloproteinase‐9 activity, decrease in tissue inhibitor of metalloproteinase‐1 expression, and increase in survivin and S100A4 expression, each effect being consistent with accelerated migration/invasion as a prelude to metastasis. Our findings suggest introduction of iNOS inhibitors as pharmacologic adjuvants for glioblastoma PDT.This article is protected by copyright. All rights reserved.
      PubDate: 2016-09-08T09:45:22.725513-05:
      DOI: 10.1111/php.12636
  • Disinfection and Mechanistic Insights of E. coli in Water by Bismuth
           Oxyhalide Photocatalysis
    • Authors: Ilana Sherman; Yoram Gerchman, Yoel Sasson, Hani Gnayem, Hadas Mamane
      Abstract: This study demonstrates the potential of a new BiOCl0.875Br0.125 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 1.5 and 3.6 log inactivation, respectively, after 40 min irradiation. The log inactivation vs. Ct curve for E. coli by UVA/BiOCl0.875Br0.125 was fairly linear, with Ct = 10 g L−1×min, resulting in 2‐log inactivation. Photocatalytic treatment led to membrane damage, but without lipid peroxidation. Accordingly, protein was released from the cells after UVA or UVA/BiOCl0.875Br0.125 treatment. Photocatalysis also increased endonuclease‐sensitive sites vs. photolysis alone, by an unknown mechanism. Finally, E. coli inactivation was not influenced by the addition of tert‐butanol or L‐histidine, implying that neither hydroxyl radicals nor singlet oxygen reactive species are involved in the inactivation process.This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-17T02:50:20.725368-05:
      DOI: 10.1111/php.12635
  • Protective Effect of Curcumin Against Acute Ultraviolet B Irradiation
           Induced Photo‐damage
    • Authors: Huaping Li; Aili Gao, Na Jiang, Qing Liu, Bihua Liang, Runxiang Li, Erting Zhang, Zhenjie Li, Huilan Zhu
      Abstract: 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). Topical application of curcumin significantly inhibited acute UVB (540 mJ/cm2, for 3 successive days)‐induced inflammatory cells, collagen accrementition derangement and lipid peroxidation, and effectively induced NF‐E2‐related factor 2 (Nrf2) nuclear accumulation in Uncovered (Uncv) hairless mice skin. Treatment of HaCaT cells with curcumin significantly attenuated acute UVB (300 mJ/cm2)‐induced lactate dehydrogenase (LDH) release, intracellular reactive oxygen species (ROS) production and DNA damage, activated the expression of the phase II detoxifying enzymes and promoted DNA repair activity. The photoprotective effect provided by curcumin was potential associated with modulation of Nrf2–dependent antioxidant response. Our study suggested that curcumin is a potential agent for preventing and/or treating UV radiation induced acute inflammation and photoaging.This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-12T03:55:22.752187-05:
      DOI: 10.1111/php.12628
  • Objective Detection of Oral Carcinoma with Multispectral Fluorescence
           Lifetime Imaging In Vivo
    • Authors: Bilal H. Malik; Joohyung Lee, Shuna Cheng, Rodrigo Cuenca, Joey M. Jabbour, Yi‐Shing Lisa Cheng, John Wright, Beena Ahmed, Kristen C. Maitland, Javier A. Jo
      Abstract: Successful early detection and demarcation of oral carcinoma can greatly impact the associated morbidity and mortality rates. Current methods for detection of oral cancer include comprehensive visual examination of the oral cavity, typically followed by tissue biopsy. A noninvasive means to guide the clinician in making a more objective and informed decision towards tissue biopsy can potentially improve the diagnostic yield of this process. To this end, we investigate the potential of fluorescence lifetime imaging (FLIM) for objective detection of oral carcinoma in the hamster cheek pouch model of oral carcinogenesis in vivo. We report that systematically selected FLIM features can differentiate between low‐risk (normal, benign and low‐grade dysplasia) and high‐risk (high‐grade dysplasia and cancer) oral lesions with sensitivity and specificity of 87.26% and 93.96%, respectively. We also show the ability of FLIM to generate ‘disease’ maps of the tissue which can be used to evaluate relative risk of neoplasia. The results demonstrate the potential of multispectral FLIM with objective image analysis as a noninvasive tool to guide comprehensive oral examination.This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-06T21:34:36.427675-05:
      DOI: 10.1111/php.12627
  • Synthesis and Modification of Zn‐doped TiO2 Nanoparticles for the
           Photocatalytic Degradation of Tetracycline
    • Authors: Shuo Pang; Ji‐guo Huang, Yun Su, Bo Geng, Su‐yuan Lei, Yu‐ting Huang, Cong Lyu, Xing‐juan Liu
      Abstract: The synthesis of Zn‐doped TiO2 nanoparticles by sol‐gel method was investigated in this study, as well as its modification by H2O2. The catalyst was characterized by transmission electron microscopy, X‐ray diffraction, Brunauer‐Emmett‐Teller, UV‐visible reflectance spectra and X‐ray photoelectron spectroscopy (XPS). The results indicated that doping Zn into TiO2 nanoparticles could inhibit the transformation from anatase phase to rutile phase. Zn existed as the second valence oxidation state in the Zn‐doped TiO2. Zn‐doped TiO2 that was synthesized by 5% Zn doping at 450 °C exhibited the best photocatalytic activity. Then, the H2O2 modification further enhanced the photocatalytic activity. Zn doping and H2O2 modifying narrowed the band gap and efficiently increased the optical absorption in visible region. The optimal degradation rate of tetracycline by Zn‐doped TiO2 and H2O2 modified Zn‐doped TiO2 was 85.27% and 88.14%. Peroxide groups were detected in XPS analysis of H2O2 modified Zn‐doped TiO2, favoring the adsorption of visible light. Furthermore, Zn‐doped TiO2 modified by H2O2 had relatively good reusability, exhibiting a potential practical application for tetracycline's photocatalytic degradation.This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-06T15:45:38.498958-05:
      DOI: 10.1111/php.12626
  • Deficient Nucleotide Excision Repair in Squamous Cell Carcinoma Cells
    • Authors: Tiffany K. Dong; Katherine Ona, Amy E. Scandurra, Stephanie K. Demetriou, Dennis H. Oh
      Abstract: Squamous cell carcinomas (SCCs) are associated with ultraviolet radiation and multiple genetic changes, but the mechanisms leading to genetic instability are unclear. SCC cell lines were compared to normal keratinocytes for sensitivity to ultraviolet radiation, DNA repair kinetics, and DNA repair protein expression. Relative to normal keratinocytes, four SCC cell lines were all variably sensitive to ultraviolet radiation and, except for the SCC25 cell line, were deficient in global repair of cyclobutane pyrimidine dimers, though not 6‐4 photoproducts. Impaired DNA repair of cyclobutane pyrimidine dimers was associated with reduced mRNA expression from XPC but not DDB2 genes which each encode key DNA damage recognition proteins. However, levels of XPC or DDB2 proteins or both were variably reduced in repair‐deficient SCC cell lines. p53 levels did not correlate with DNA repair activity or with XPC and DDB2 levels, but p63 levels were deficient in cell lines with reduced global repair. Repair‐proficient SCC25 cells depleted of p63 lost XPC expression, early global DNA repair activity and UV‐resistance. These results demonstrate that some SCC cell lines are deficient in global nucleotide excision repair, and support a role for p63 as a regulator of nucleotide excision repair in SCCs.This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-06T12:06:45.722471-05:
      DOI: 10.1111/php.12625
  • Distinct Role of Sesn2 in Response to UVB‐induced DNA Damage and
           UVA‐induced Oxidative Stress in Melanocytes
    • Authors: Baozhong Zhao; Palak Shah, Lei Qiang, Tong‐Chuan He, Andrey Budanov, Yu‐Ying He
      Abstract: Ultraviolet (UV) radiation, including both UVB and UVA irradiation, is the major risk factor for causing skin cancer including melanoma. Recently we have shown that Sesn2, a member of the evolutionarily conserved stress‐inducible protein family Sestrins (Sesn), is up‐regulated in human melanomas as compared to melanocytes in normal human skin, suggesting an oncogenic role of Sesn2. However, the role of Sesn2 in UVB and UVA response is unknown. Here we demonstrated that both UVB and UVA induce Sesn2 up‐regulation in melanocytes and melanoma cells. UVB induces Sesn2 expression through the p53 and AKT3 pathways. Sesn2 negatively regulates UVB‐induced DNA damage repair. In comparison UVA induces Sesn2 up‐regulation through mitochondria but not Nrf2. Sesn2 ablation increased UVA‐induced Nrf2 induction and inhibits UVA‐induced ROS production, indicating that Sesn2 acts as an upstream regulator of Nrf2. These findings suggest previously unrecognized mechanisms in melanocyte response to UVB and UVA irradiation and potentially in melanoma formation.This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T09:50:19.827165-05:
      DOI: 10.1111/php.12624
  • Attitudes, Beliefs and Measures Taken by Parents to Protect Their Children
           from the Sun in Guangzhou City, China
    • Authors: Miaojian Wan; Rong Hu, Ying Li, Yaning Wang, Xiaoyuan Xie, Pan Yue, Lei Guan, Wei Lai
      Abstract: Excessive sun exposure can cause sunburn, suntan, skin photoaging, and even skin cancer. Skin photoaging conflicts with the human pursuit of a young and beautiful appearance. Some research data indicate that the incidence of skin cancer in the Chinese has been increasing, although it remains lower than in whites. To estimate the prevalence of sun protection used on Chinese children aged 3–13 years and identify its predictors, a population‐based cross‐sectional questionnaire was give to 3,684 parents/guardians of children in Guangzhou, China of which 3,083 questionnaires were returned. Of those returned, 35.5% of parents/guardians reported regularly using sun protection on their children and the primary reason cited was to prevent sunburn. Hats and handheld umbrellas were the most frequently used measures; sunscreen was less common, and when used, 48.8% of parents/guardians still reapplied sunscreen on their children every 2.0–3.0 h. Parental age, parents using sun protection measures themselves when outdoors, and the child's sex were factors associated with regular use of sun protection on children. These results suggest that sun protection campaigns targeted toward parents and children need to be conducted in Guangzhou, or throughout China, to strengthen awareness about sun protection and address any inadequate protocols of sun protection.This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T09:45:23.857185-05:
      DOI: 10.1111/php.12623
  • FAD and MTHF are the in‐planta Cofactors of Arabidopsis thaliana
           Cryptochrome 3
    • Authors: Tanja Göbel; Stefan Reisbacher, Alfred Batschauer, Richard Pokorny
      Abstract: Members of the cryptochrome/photolyase family (CPF) of proteins utilize non‐covalently bound light‐absorbing cofactors for their biological function. Usually, the identity of these cofactors is determined after expression in heterologous systems leaving the question unanswered whether these cofactors are identical to the indigenous ones. Here, cryptochrome 3 from Arabidopsis thaliana was expressed as a fusion with the green fluorescent protein in Arabidopsis plants. Besides the confirmation of the earlier report of its localization in chloroplasts, our data indicate that fractions of the fusion protein are present in the stroma and associated with thylakoids, respectively. Furthermore, it is shown that the fusion protein expressed in planta contains the same cofactors as the His6‐tagged protein expressed in Escherichia coli, i.e., flavin adenine dinucleotide and N5,N10‐methenyltetrahydrofolate. This demonstrates that the heterologously‐expressed cryptochrome 3, characterized in a number of previous studies, is a valid surrogate of the corresponding protein expressed in plants. To our knowledge, this is also a first conclusive analysis of cofactors bound to an Arabidopsis protein belonging to the CPF and purified from plant tissue.This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T09:45:21.608782-05:
      DOI: 10.1111/php.12622
  • Near–infrared–Responsive Peptide that Targets Collagen Fibrils
           to Induce Cytotoxicity
    • Authors: Masayuki Honda; Aoi Odawara, Ikuro Suzuki, Morio Shimada, Kohki Yoshikawa, Tomoko Okada
      Abstract: A novel conjugate, PHG10–dye, was synthesized using a collagen peptide and a near‐infrared (NIR) responsive dye to achieve targeted cytotoxicity. The collagen peptide motif, ‐(Pro‐Hyp‐Gly)10‐ (PHG10), was incorporated for targeting collagen fibrils that are excessively produced by activated fibroblasts around tumor cells. PHG10–dye was purified by HPLC and identified by MALDI‐MS. The phototoxicity and cytotoxicity of PHG10–dye were examined using human glioma cells (HGCs). Fluorescent images indicated that PHG10–dye preferably assembled to collagen‐coated HGCs compared with non‐coated HGCs. Under irradiation with NIR light, effective cytotoxicity was observed on collagen‐coated HGCs within 20 min. Because phototoxicity and cytotoxicity are dependent on the assembled amount of PHG10–dye, the targeting of collagen fibrils by the collagen peptide motif PHG10 is assured.This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-18T11:15:31.735262-05:
      DOI: 10.1111/php.12621
  • The Effects of Ultraviolet Ray Eye Irradiation on DSS‐induced
           Ulcerative Colitis in Mice
    • Authors: Keiichi Hiramoto; Yurika Yamate, Eisuke F. Sato
      Abstract: Ultraviolet (UV) eye irradiation denatures the cells of the intestine. This study examined the action of UVA and UVB on dextran sodium sulfate (DSS)‐induced ulcerative colitis. We produced a mouse model of ulcerative colitis by administering DSS for five days, and irradiated the eye with UVB or UVA for each day of the DSS‐treatment period. DSS‐induced ulcerative colitis was deteriorated by the UVB eye irradiation. Conversely, the symptoms improved with UVA eye irradiation. The levels of adrenocorticotropic hormone (ACTH), corticotropin‐releasing hormone (CRH), urocortin 2, interleukin (IL)‐18, IL‐6, and histamine in the blood increased after the UVB eye irradiation of DSS‐treated mice (UVB/DSS‐treated mice). In contrast, the β‐endorphin level in the blood of the UVA/DSS‐treated mice increased and the levels urocortin 2, tumor necrosis factor (TNF)‐α and histamine decreased. Furthermore, in the colon, the expression of melanocortin‐2 receptors (MC2R) increased in the UVB/DSS‐treated mice, while the expression of μ‐opioid receptors increased in the UVA/DSS‐treated mice. When an ACTH inhibitor was administered, UVB eye irradiation caused the deterioration of DSS‐treated ulcerative colitis, while the effect of UV eye irradiation disappeared with a μ‐opioid receptor antagonist. These results suggested that UV eye irradiation plays an important role in DSS‐induced ulcerative colitis.This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-18T11:06:55.377456-05:
      DOI: 10.1111/php.12620
  • Differential Laser‐induced Perturbation Spectroscopy for Analysis of
           Mixtures of the Fluorophores L‐Phenylalanine, L‐Tyrosine, and
           L‐Tryptophan Using a Fluorescence Probe
    • Authors: Erman K. Oztekin; David W. Hahn
      Abstract: Quantitative detection of common endogenous fluorophores is accomplished using differential laser‐induced perturbation spectroscopy (DLIPS) with a 193‐nm UV fluorescence probe and various UV perturbation wavelengths. In this study, DLIPS is explored as an alternative to traditional fluorescence spectroscopy alone, with a goal of exploring natural fluorophores pursuant to biological samples and tissue analysis. To this end, aromatic amino acids, namely, L‐Phenylalanine, L‐Tyrosine and L‐Tryptophan are mixed with differing mass ratios and then classified with various DLIPS schemes. Classification with a traditional fluorescence probe is used as a benchmark. The results show a 20% improvement in classification performance of the DLIPS method over the traditional fluorescence method using partial least squares (PLS) analysis. Additional multivariate analyses are explored and the relevant photochemistry is elucidated in the context of perturbation wavelengths. We conclude that DLIPS is a promising biosensing approach with potential for in vivo analysis given the current findings with fluorophores relevant to biological tissues.This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-15T03:05:32.109278-05:
      DOI: 10.1111/php.12618
  • Photoprotective Potential of Baccharis antioquensis (Asteraceae) as
           Natural Sunscreen
    • Authors: Juan C. Mejía‐Giraldo; Robert Winkler, Cecilia Gallardo, Ana M. Sánchez‐Zapata, Miguel A. Puertas‐Mejía
      Abstract: In the quest for new natural agents of photoprotection, we evaluated the photoprotective and antioxidant activity of B. antioquensis leaf extracts as well as its phenolic composition. The methanolic extract treated with activated carbon showed the highest absorption coefficients for UVA‐UVB radiation, as well as an antioxidant capacity comparable to BHT. Furthermore, the formulation containing this extract showed suitable sensorial and photostable characteristics for topical use, and significant values of UVAPF, critical wavelength (λc), UVA/UVB ratio and SPF (5.3, 378 nm, 0.78 and 9.1±0.1, respectively). In addition, three glycoside derivatives of quercetin, a kaempferol glycoside and a derivative of caffeic acid were the main polyphenolic compounds identified. These results demonstrate the potential of B. antioquensis extracts to be used as active components of novel, natural sunscreens.This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-15T03:05:29.864055-05:
      DOI: 10.1111/php.12619
  • Germ Cell Testicular Cancer Incidence, Latitude and Sunlight Associations
           in the United States and Australia
    • Authors: Robert J. Biggar; Peter D. Baade, Jiandong Sun, Lindsay E. Brandon, Michael Kimlin
      Abstract: International patterns suggest germ cell testicular cancer (GCTC) incidence may be lower in lower latitudes. To investigate this possibility, we examined GCTC incidence by latitude (population‐centroid in 2000) for men >15 years within two reasonably homogeneous countries, the United States (US) and Australia. In the US, we examined age‐adjusted incidence/latitude trends using data from states (2001‐2010) and local‐area registries (1980‐2011). In Australia, we evaluated incidence/latitude trends in 61 Statistical Divisions (2000‐2009). In White US men (68,566 cases), state incidences increased by latitude, rising 5.74% (4.45‐7.05%) per 5°North latitude increment. Similar trends were found for seminoma and non‐seminoma subtypes (p
      PubDate: 2016-07-11T08:26:48.537791-05:
      DOI: 10.1111/php.12617
  • Ultra‐weak Photon Emission from the Seed Coat in Response to Temperature
           and Humidity ‐ A Potential Mechanism for Environmental Signal
           Transduction in the Soil Seed Bank
    • Authors: Steven Footitt; Simonetta Palleschi, Eugenio Fazio, Raffaele Palomba, William E Finch‐Savage, Leopoldo Silvestroni
      Abstract: Seeds beneath the soil sense the changing environment to time germination and seedling emergence with the optimum time of year for survival. Environmental signals first impact with the seed at the seed coat. To investigate whether the seed coat has a role in environmental sensing we investigated their ultra‐weak photon emission (UPE) under the variable temperature, relative humidity and oxygen conditions they could experience in the soil seed bank. Using a custom built luminometer we measured UPE intensity and spectra (300‐700 nm) from Phaseolus vulgaris seeds, seed coats and cotyledons. UPE was greatest from the internal surface of the seed coat. Seed coat UPE increased concomitantly with both increasing temperature and decreasing relative humidity. Emission was oxygen dependent and it was abolished by treatment with dinitrophenylhydrazine demonstrating the key role of seed coat carbonyls in the phenomenon. We hypothesize that beneath the soil surface the attenuation of light (virtual darkness: low background noise) enables seeds to exploit UPE for transducing key environmental variables in the soil (temperature, humidity and oxygen) to inform them of seasonal and local temperature patterns. Overall, seed coats were found to have potential as effective transducers of key fluctuating environmental variables in the soil.This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-08T01:55:35.057823-05:
      DOI: 10.1111/php.12616
  • Plantamajoside Inhibits UVB and Advanced Glycation End Products‐induced
           MMP‐1 Expression by Suppressing the MAPK and NF‐ĸB Pathways in HaCaT
    • Authors: Ah‐Ram Han; Mi‐Hyun Nam, Kwang‐Won Lee
      Abstract: Photoaging and glycation stress are major causes of skin deterioration. Oxidative stress caused by ultraviolet B (UVB) irradiation can upregulate matrix metalloprotease 1 (MMP‐1), a major enzyme responsible for collagen damage in the skin. Advanced glycation end products (AGEs) accumulate via gradual formation from skin proteins, especially from long‐lived proteins such as dermal elastin and collagen. Plantamajoside (PM), isolated from Plantago asiatica, has various biological effects including anti‐inflammatory and antioxidant effects. In this study, we assessed the protective effects of PM on a human keratinocyte cell line (HaCaT) and primary human dermal fibroblasts (HDF) against stress caused by glyceraldehyde‐induced AGEs (glycer‐AGEs) with UVB irradiation. We found that PM attenuated UVB‐and‐glycer‐AGEs–induced MMP‐1 expression in HaCaT and HDF cells and proinflammatory cytokines expression by inhibiting the phosphorylation of mitogen‐activated protein kinases (MAPKs) activated by reactive oxygen species. Specific inhibitors of NF‐κB and MAPKs attenuated the induced expression of MMP‐1. PM also inhibited the phosphorylation of IκBα, and reduced nuclear translocation of NF‐κB in these cells. Furthermore, PM attenuated the upregulation of receptor for AGEs (RAGE) by glycer‐AGEs with UVB irradiation. Therefore, our findings strongly suggest that PM is a promising inhibitor of skin photoaging.This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-27T03:05:52.855034-05:
      DOI: 10.1111/php.12615
  • A Possible Phenom of Persistence in Pseudomonas aeruginosa Treated With
           Methylene Blue and Red Light
    • Authors: Ana Florencia Forte Giacobone; Maria Fernanda Ruiz Gale, Elsa Noemí Hogert, Oscar Juan Oppezzo
      Abstract: Planktonic Pseudomonas aeruginosa cells harvested in stationary phase were exposed to red light in presence of methylene blue to study the potential occurrence of persistence in bacterial populations submitted to photodynamic antimicrobial therapy. Survival curves revealed the existence of small subpopulations of cells exhibiting increased ability to tolerate the treatment. These subpopulations were detected even using high concentrations of photosensitizer, whether added in a single step or following a fractionated scheme, and when the irradiation medium was modified to delay the photodecomposition of methylene blue. When cells grown from survivors to the treatment were cultured and exposed to red light and dye, their responses were similar to that of the original strain. These results exclude exhaustion of the photosensitizer and selection of resistant mutants as explanations for the features of the survival curves. Cells able to tolerate the treatment were found even when radiation was imparted at a high dose rate. They exhibit a response typical of persisters, which tolerate antimicrobial agents due to transient and reversible changes in their phenotype, suggesting that persistence is a factor to consider upon evaluating the efficacy of photodynamic antimicrobial therapy.This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-25T09:50:30.647571-05:
      DOI: 10.1111/php.12613
  • Surface Arginine Saturation Effect on Unfolding Reaction of Firefly
           Luciferase: A Thermodynamic and Kinetic Perspective
    • Authors: Zahra Solgi; Khosrow Khalifeh, Saman Hosseinkhani, Bijan Ranjbar
      Abstract: Replacement of some hydrophobic solvent‐exposed residues in Lampyris turkestanicus luciferase with arginine increases thermostability of this enzyme. Herein, thermodynamic and kinetic of unfolding reactions of wild type (WT), E354R/356R, E354R/356R‐I232R and E354R/356R‐Q35R/L182R/I232R variants has been investigated. Fluorescence and Far‐UV circular dichroism signals using urea as chemical denaturant indicated that the value of ∆G(H2O) for all variants is greater than that of WT enzyme. Analysis of m‐values, as a measure of difference in the solvent accessible surface area between the native and denatured states of protein, revealed that higher stability of mutants is related to their higher degree of compactness in the folded state. Results of unfolding kinetic experiments showed that all variants have three‐exponential behavior in which, they unfolded with three rate constants and corresponding amplitudes. Increasing the rate constants of fast unfolding phase in mutants relative to WT protein may be attributed to more compactness and more kinetic sensitivity of their folded state to urea. However, more population of WT protein was unfolded from fast unfolding phase. Results of this investigation highlight kinetic stability of luciferase via a slow rate of unfolding.This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-25T09:45:25.91839-05:0
      DOI: 10.1111/php.12614
  • Reduced Levels of Tissue Inhibitors of Metalloproteinases (TIMPs) in UVB
           Irradiated Corneal Epithelium
    • Authors: Taras Ardan; Lucie Němcová, Božena Bohuslavová, Adéla Klezlová, Štěpán Popelka, Hana Studenovská, Eva Hrnčiarová, Jitka Čejková, Jan Motlík
      Abstract: Tissue inhibitors of metalloproteinases (TIMPs) are the major endogenous regulators of metalloproteinase activity in tissues. TIMPs are able to inhibit activity of all known matrix metalloproteinases (MMPs) and thus participate in controlling extracellular matrix synthesis and degradation. We showed previously elevated expressions of MMPs in the rabbit corneal epithelium upon UVB exposure and suggested that these enzymes might be involved in corneal destruction caused by excessive proteolysis. The aim of this study was to investigate TIMPs in the corneal epithelium after UV irradiation using immunohistochemical and biochemical methods. We found that as compared to control rabbit corneas where relatively high levels of TIMPs were present in the epithelium, repeated irradiation of the cornea with UVB rays (not with UVA rays of similar doses) significantly decreased TIMPs in corneal epithelial cells. The results of this study point to the suggestion that the decrease of TIMPs in the corneal epithelium after UVB irradiation contributes to increased proteolytic activity of MMPs in UVB irradiated corneal epithelium found previously.This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T02:25:26.941082-05:
      DOI: 10.1111/php.12612
  • Identification of a Fluorescent Protein from Rhacostoma atlantica
    • Authors: Michael R. Tota; Jeanna M. Allen, Jan O. Karolin, Chris D. Geddes, William W.Ward
      Abstract: We have cloned a novel fluorescent protein from the jellyfish Rhacostoma atlantica. The closest known related fluorescent protein is the Phialidium yellow‐fluorescent protein, with only a 55% amino acid sequence identity. A somewhat unusual alanine‐tyrosine‐glycine amino acid sequence forms the presumed chromophore of the novel protein. The protein has an absorption peak at 466 nm and a fluorescence emission peak at 498 nm. The fluorescence quantum yield was measured to be 0.77 and the extinction coefficient is 58,200 M−1 cm−1. Several mutations were identified that shift the absorption peak to about 494 nm and the emission peak to between 512 and 514 nm.This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-11T08:15:25.856241-05:
      DOI: 10.1111/php.12609
  • Issue Information
    • Pages: 649 - 650
      PubDate: 2016-09-19T06:25:07.292491-05:
      DOI: 10.1111/php.12517
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