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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  [1589 journals]
  • Continuum Electrostatic Calculation on Bovine Rhodopsin: Protonation and
           the Effect of the Membrane Potential
    • Authors: Elisa Bombarda; G. Matthias Ullmann
      Abstract: In this work, we calculate the protonation probabilities of titratable residues of bovine rhodopsin using the Poisson-Boltzmann equation. We also consider the influence of the membrane potential. Our results indicate that at physiological pH, the titratable groups directly involved in photosensing, namely Glu113, Glu181 and the retinal Schiff base, are charged. In contrast, the residues Asp83, Glu122, and His211, which are buried in the membrane, are uncharged. However, since these later residues are localized in the middle of the membrane, they are exposed to the membrane potential more strongly, which may have important functional implications. Despite of their large distance, Asp83 and Glu122 interact relatively strongly. Since these two residues are in contact with opposite sides of the membrane, the membrane potential has different effects on them, which allows an enhancement of the membrane potential signal. An analysis of the different contributions to the protonation energy indicates that conformational changes that reduce the desolvation penalty of Asp83, Glu122, and His211 may lead to a complex protonation pattern change that allows an influence of the membrane potential on the function of rhodopsin. The high degree of evolutionary conservation of these three buried residues support the idea of their functional importance. Our results are inline with many experimental findings and lead to new ideas that can be experimentally tested.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-24T08:36:00.170592-05:
      DOI: 10.1111/php.12777
       
  • High-level Ab Initio Absorption Spectra Simulations of Neutral, Anionic
           and Neutral+ Chromophore of Green Fluorescence Protein Chromophore Models
           in Gas Phase and Solution
    • Authors: Ivelina Georgieva; Adelia J. A. Aquino, Natasha Trendafilova, Hans Lischka
      Abstract: Semi-classical ab initio simulations of the absorption spectra of neutral and anionic p-hydroxybenzylidene-2,3-dimethylimidazolinone (p-HBDI), a model chromophore of Green Fluorescent Protein (GFP) and of a positively charged neutral (N+)-HBDI chromophore model were performed in gas phase with the resolution-of-identity algebraic diagrammatic construction through second-order (RI-ADC(2)) method. The calculated absorption spectra in gas phase are composed of one band centered at 3.51 eV (HBDI), 2.50 eV (HBDI-) and 3.02 eV ((N+)-HBDI) owing to the absorption of the first 1ππ* transition. Band maxima are red-shifted by ~0.1 eV with respect to the corresponding vertical energies. The COSMO-RI-ADC(2) calculations of the first vertical excitation energy of HBDI, HBDI- and (N+)-HBDI forms in polar solution including microsolvation simulate the observed solvent red-shift for neutral HBDI and the solvent blue-shift of the HBDI- and (N+)-HBDI forms. The state-specific solvation approach applied to TDDFT calculations reproduced the experimental solvent shifts for the three HBDI forms, demonstrating a more accurate theoretical description as compared to the linear-response TDDFT approach.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-24T00:11:10.833533-05:
      DOI: 10.1111/php.12778
       
  • Validation of Sun Exposure Reported Annually Against Interim Self-report
           and Daily Sun Diaries
    • Authors: Laura King; Fan Xiang, Ashwin Swaminathan, Keith Dear, Simone L Harrison, Ingrid van der Mei, Michael G Kimlin, Catherine D'Este, Robyn M Lucas
      Abstract: Data on personal sun exposure over a period exceeding the immediate past days or weeks is typically self-reported in brief questionnaire items. The validity of such self-reporting of longer-term personal sun exposure, e.g. over a year, including detail on variation across seasons, has not previously been investigated. In a volunteer sample (n = 331) of Australian adults age 18 years and over, we assessed the 12-month reliability of sun exposure reported separately for each season, and its accuracy compared to a daily sun diary in the same season. Seasonal time outdoors displayed fair to good reliability between baseline and end of study (12 months), with responses showing higher agreement at lower levels of time outdoors. There was good agreement for ranking of individuals’ time outdoors with the daily sun diary data, although the actual diary time outdoors was typically considerably lower than the self-reported questionnaire data. Place of residence, education, being a smoker, day of the week (i.e. working day vs. non-working day), and working mainly outdoors were significant predictors of agreement. While participants over-estimated their actual time outdoors, the self-report questionnaire provided a valid ranking of long term sun exposure against others in the study that was reliable over time.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-22T10:10:29.294254-05:
      DOI: 10.1111/php.12780
       
  • Addition of Hydrogen Peroxide to Groundwater with Natural Iron Induces
           Water Disinfection by Photo-Fenton at Circumneutral pH and other
           Photochemical Events
    • Authors: Héctor Mario Gutiérrez-Zapata; John Jairo Alvear-Daza, Julián Andrés Rengifo-Herrera, Janeth Sanabria
      Abstract: Samples of natural groundwater (with low turbidity, neutral pH and 0.3 mg L−1 iron concentration) inoculated with Escherichia coli K-12, were exposed to simulated solar light both in the presence and absence 10 mg L−1 of H2O2. Results demonstrated that the viability of E. coli (by DVC-FISH) was grounded to zero after 360 min of irradiation. This abatement could be caused by the oxidative stress induced by •OH radicals or another photo-induced reactive oxygen species.Two 23 factorial experimental designs enabled the evaluation of the effects of chemical factors on the inactivation of E. coli. The first experimental design considered the pH, iron and H2O2, while the second evaluated the ions fluoride, carbonate and phosphate found in groundwater. pH was found to play a key role in the inactivation of E. coli. The best reduction in viability was obtained at the lower pH (6.75), while a non-significant effect was observed when iron or H2O2 concentrations were raised. At higher concentrations, anions such as carbonate and phosphate, negatively affected the E. coli abatement. However, a higher concentration of fluoride accelerated it. In all experiments, the pH was observed to rise to values higher than 8.0 units after 360 min of treatment.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-22T10:00:30.891266-05:
      DOI: 10.1111/php.12779
       
  • Marine Bioluminescence: Measurement by a Classical Light Sensor and
           Related Foraging Behaviour of a Deep Diving Predator
    • Authors: Jade Vacquié-Garcia; Jérôme Mallefet, Frédéric Bailleul, Baptiste Picard, Christophe Guinet
      Abstract: Bioluminescence is produced by a broad range of organisms for defense, predation or communication purposes. Southern elephant seal (SES) vision is adapted to low intensity light with a peak sensitivity, matching the wavelength emitted by myctophid species, one of the main prey of female SES. A total of 11 satellite-tracked female SES were equipped with a Time-Depth-Light 3D-accelerometers (TDR10-X) in order to assess whether bioluminescence could be used by SES to locate their prey. First, we demonstrated experimentally that the TDR10-X light sensor was sensitive enough to detect natural bioluminescence; however, we highlighted a low distance detection of the sensor. Then, we linked the number of Prey Capture Attempts (PCA), assessed from accelerometer data, with the number of detected bioluminescence events. PCA was positively related to bioluminescence, which provides strong support that bioluminescence is involved in predator-prey interactions for these species. However, the limitations of the sensor did not allow us to discern whether bioluminescence (i) provided remote indication of the biological richness of the area to SES, (ii) was emitted as a mechanic reaction, or (iii) was emitted as a defense mechanism in response to SES behaviour.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-20T01:35:46.52876-05:0
      DOI: 10.1111/php.12776
       
  • Mechanistic Analysis of Fluorescence Quenching of Reduced Nicotinamide
           Adenine Dinucleotide by Oxamate in Lactate Dehydrogenase Ternary Complexes
           
    • Authors: Huo-Lei Peng; Robert Callender
      Abstract: Fluorescence of Reduced Nicotinamide Adenine Dinucleotide (NADH) is extensively employed in studies of oxidoreductases. A substantial amount of static and kinetic work has focused on the binding of pyruvate or substrate mimic oxamate to LDH•NADH where substantial fluorescence quenching is typically observed. However, the quenching mechanism is not well understood limiting structural interpretation. Based on time-dependent density functional theory (TDDFT) computations with cam-B3LYP functional in conjunction with the analysis of previous experimental results, we propose that bound oxamate acts as an electron acceptor in the quenching of fluorescence of NADH in the ternary complex, where a charge transfer (CT) state characterized by excitation from the highest occupied molecular orbital (HOMO) of the nicotinamide moiety of NADH to the lowest unoccupied molecular orbital (LUMO) of oxamate exists close to the locally excited (LE) state involving only the nicotinamide moiety. Efficient quenching in the encounter complex like in pig heart LDH requires that oxamate forms a salt bridge with Arg-171 and hydrogen bonds with His-195, Thr-246 and Asn-140. Further structural rearrangement and loop closure, which also brings about another hydrogen bond between oxamate and Arg-109, will increase the rate of fluorescence quenching as well.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-09T01:45:37.885979-05:
      DOI: 10.1111/php.12775
       
  • Construction of Er3+:YAlO3/RGO/TiO2 Hybrid Electrode
           With Enhanced Photoelectrocatalytic Performance in
           Methylene Blue Degradation Under Visible Light
    • Authors: Xian Zhou; Jun Zhang, Yue Ma, Hanqing Cheng, Shaozhu Fu, Dandan Zhou, Shuangshi Dong
      Abstract: Much attention has been paid on doping TiO2 to narrow its band gap to promote the absorption of visible light and restrain the recombination of electron-hole pairs to improve its efficiency in photoelectrocatalysis (PEC) under visible light irradiation. However, the oxidation potential energy of photo-induced holes for the modified catalysts by visible light excitation is lower than that without modification by UV excitation. In this work, we synthesized a co-coupled TiO2 electrode (denoted ERT) with the Er3+:YAlO3 and reduced graphene oxide (RGO), achieving the synergetic effect of visible-light-to-UV up conversion and response and great electron transfer ability. The effects of external bias voltage, electrolyte concentration and pH on the PEC activity were studied with the methylene blue (MB) as the target pollutant. The results indicated that PEC by the ERT electrode showed the highest MB removal compared with those by the electrodes coupled with RGO or Er3+:YAlO3 alone. In addition, the kinetic rate constant of the PEC process using the ERT electrode was higher than the sum of those of the photocatalytic and electrocatalytic processes. The optimal conditions for PEC by the ERT electrode were an external bias voltage of 1.0 V, 0.1 mol/L Na2SO4 and pH=10.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-09T01:45:33.602877-05:
      DOI: 10.1111/php.12774
       
  • Synthesis, Photophysics and PDT Evaluation of Mono-, Di-, Tri- and
           Hexa-PEG Chlorins for Pointsource Photodynamic Therapy
    • Authors: Tobias Bornhütter; Ashwini A. Ghogare, Annegret Preuß, Alexander Greer, Beate Röder
      Abstract: Pointsource photodynamic therapy (PSPDT) is a newly developed fiber optic method aimed at the delivery of photosensitizer, light and oxygen to a diseased site. Because of a need for developing photosensitizers with desirable properties for PSPDT, we have carried out a synthetic, photophysical and phototoxicity study on a series of PEGylated sensitizers. Chlorin and pheophorbide sensitizers were readily amenable to our synthetic PEGylation strategy to reach triPEG and hexaPEG galloyl pheophorbides and mono-, di-, triPEG chlorins. On screening these PEG sensitizers, we found that increasing the number of PEG groups, except for hexaPEGylation, increases phototoxicity. We find that three PEG groups but not less or more was optimal. Of the series tested, a triPEG gallyol pheophorbide and a triPEG chlorin were the most efficient at generating singlet oxygen, and produced the highest phototoxicity and lowest dark toxicity to Jurkat cells. A detailed kinetic analysis of the PEGylated sensitizers in solution and cell culture and media is also presented. The data provide us with steps in the development of PSPDT to add to the PDT tools we have in general.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-09T01:35:26.514398-05:
      DOI: 10.1111/php.12773
       
  • The Evaluation of Non-invasive Measurements of Erythema as a Potential
           Surrogate for DNA Damage in Repetitively UV-exposed Human Skin
    • Authors: Sharon A. Miller; Sergio G. Coelho, Yuji Yamaguchi, Vincent J. Hearing, Janusz Z. Beer, Frank de Gruijl
      Abstract: Erythema (i.e. visible redness) and DNA damage caused by ultraviolet radiation (UVR) in human skin have similar action spectra and show good correlation after a single exposure to UVR. We explored the potential to use instrumental assessments of erythema as a surrogate for DNA damage after repeated exposures to UVR. We exposed 40 human subjects to three different exposure schedules using two different UVR sources. Cyclobutane pyrimidine dimers (CPDs) in skin biopsies were measured by immunofluorescence and erythema was assessed by both the Erythemal Index (EI) and the Oxy-hemoglobin (Oxy-Hb) content. Surprisingly, the skin with the highest cumulative dose ended up with the lowest level of DNA damage, and with the least erythema, as assessed by Oxy-Hb (but not EI) 24 h after the last UV exposure. Although the level of CPDs, on average, paralleled Oxy-Hb (R2 = 0.80 – 0.94, p = 0.03 – 0.11), the correlation did not hold for the pooled individual measurements (R2 = 0.009, p = 0.37) due to potential individual differences in UV-induced photoadaptation. We suggest that the methodology may be optimized to improve the correlation between DNA damage level and erythema to enable non-invasive risk assessment based on erythema/Oxy-Hb content for individual human subjects.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T17:25:42.023342-05:
      DOI: 10.1111/php.12772
       
  • FTIR Analysis of a Light-driven Inward Proton Pumping Rhodopsin at 77 K
    • Authors: Shota Ito; Shinya Sugita, Keiichi Inoue, Hideki Kandori
      Abstract: Parvularcula oceani xenorhodopsin (PoXeR) is a light-driven inward proton pump that was discovered from deep ocean marine bacteria. PoXeR is categorized into the same family of Anabaena sensory rhodopsin (ASR) that functions as a photochromic sensor. In this paper, we applied light-induced difference Fourier-transform infrared (FTIR) spectroscopy to PoXeR at 77 K, and the obtained spectra were compared with those of ASR. The structure and structural changes in the primary processes of PoXeR are common to all microbial rhodopsins. The red-shifted K formation (PoXeRK) was accompanied by retinal photoisomerization from the all-trans to 13-cis form resulting in a distorted structure of the retinal. The observed hydrogen out-of-plane (HOOP) vibrations were sensitive to H/D exchange, indicating that the chromophore distortion by retinal isomerization is located near the Schiff base region in PoXeR. The hydrogen-bonding strength of the protonated Schiff base is similar between PoXeR and ASR, whose acceptor is presumably a water molecule. Unlike ASR, however, PoXeR contains strongly hydrogen-bonded water (O-D stretch at 2277 cm−1 in D2O), which is also the case for outward proton pumps. The detailed structure, structural changes upon retinal photoisomerization, as well as functional correlation in PoXeR are discussed based on the present FTIR study.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T17:23:42.030513-05:
      DOI: 10.1111/php.12771
       
  • On the Simulation of Two-dimensional Electronic Spectroscopy of
           Indole-containing Peptides
    • Authors: Angelo Giussani; Jacopo Marcheselli, Shaul Mukamel, Marco Garavelli, Artur Nenov
      Abstract: A benchmark study of low-cost multi-configurational CASSCF/CASPT2 schemes for computing the electronic structure of indole is presented. This facilitates the simulation of near-ultraviolet (UV) pump visible (VIS) probe (i.e. two-color) two-dimensional electronic spectra (2DES) of homo- and hetero-aggregates as well as for processing of multiple snapshots from molecular dynamics simulations. Fingerprint excited state absorption signatures of indole are identified in a broad spectral window between 10 and 25 kcm−1. The 18-24 kcm−1 spectral window which has no absorption of the monomer and non-interacting aggregates, is ideally suited to embed charge transfer signatures in stacked aggregates. The small peptide Trp-cage, containing a tryptophan and a tyrosine amino acids, having indole and phenol as side chains, respectively, serves to prove the concept. Clear charge transfer signatures are found in the proposed spectral window for an inter-chromophore distance of 5 Å making near-UV pump VIS probe 2DES a suitable technique for resolving closely packed aggregates. We demonstrate that 2DES utilizing ultra-short pulses has the potential to resolve the nature of the spectroscopically resolved electronic states and that the line shapes of the excited state absorption signals can be correlated to the polarity of the relevant states.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T17:22:45.362785-05:
      DOI: 10.1111/php.12770
       
  • Fluorescence Sensor with A New ON1–OFF–ON2 Switching Mechanism Using
           the Excited State Intermolecular Proton Transfer Reaction of An
           Anthracene-diurea Compound
    • Authors: Hisato Matsumoto; Yoshinobu Nishimura, Tatsuo Arai
      Abstract: A new photoreaction mechanism of “Three-state molecular switch” fluorescence sensor based on ON1-OFF-ON2 sequence, was achieved by anthracene-diurea compound, which was designed by using two phenylurea groups and one anthracene, 9,10BtDSPUA. Photochemical properties of 9,10BtDSPUA and interaction between 9,10BtDSPUA and anion were investigated in detail by absorption, 1H NMR, fluorescence and fluorescence decay measurements. While the fluorescence of 9,10BtDSPUA in DMSO (ON1) was quenched in the presence of low concentration of acetate anion (OFF), fluorescence enhancement occurred by the addition of high concentration of acetate anion (ON2). This compound forms complex with acetate anion through hydrogen bonding interaction in the ground state resulted in tautomer formation by excited-state intermolecular proton transfer (ESIPT) on irradiation. Whereas single coordination of acetate anion to anthracene-diurea compound may cause fluorescence quenching, full coordination may cause fluorescence enhancement due to suppressing ESIPT. This suppressing ESIPT was occurred by electron-donating resonance effect between two urea moieties. This study is the first example of ON1-OFF-ON2 fluorescence sensor for concentration detection of acetate anion.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T17:21:20.622038-05:
      DOI: 10.1111/php.12768
       
  • Effectiveness of Photodynamic Therapy in Elimination of HPV-16 and HPV-18
           Associated with CIN I in Mexican Women
    • Authors: Elizabeth Maldonado Alvarado; M. Olivia Osorio Peralta, Alejandra Moreno Vázquez, L. Alejandra Martínez Guzmán, M. Eugenia Melo Petrone, Z.Iveth Enriquez Mar, D.Estela Jovel Galdamez, Bárbara Carrión Solana, Guadalupe Balderas Martínez, Eduarda Parra, R. Inés Castellanos Oliveros, R. Linda Bello Leiva, Araceli Espinosa Montesinos, Citlalli Barrera Mendoza, S. Eugenia Medina García, Eva Ramón Gallegos
      Abstract: The present study aimed to determine the effectiveness of photodynamic therapy (PDT), using δ-aminolevulinic acid (5-ALA), in the elimination of premalignant cervical lesions in Mexican patients with human papillomavirus (HPV) infection and/or cervical intraepithelial neoplasia (CIN). Thirty women diagnosed with CIN I and/or positive for HPV participated in the study. Topical 6% 5-ALA in gel form was applied to the uterine cervix; after 4 h, the lesion area was irradiated with a light dose of 200 J/cm2 at 635 nm. This procedure was performed three times at 48-h intervals. Clinical follow-up was performed at 3, 6 and 12 months after the initial PDT administration, by colposcopy, cervical cytology, histopathological analysis, polymerase chain reaction and hybrid capture. Of HPV-infected patients without evidence of CIN I, 80% cleared the infection, while HPV associated with CIN I was eliminated in 83% of patients (p
      PubDate: 2017-04-05T17:20:39.458713-05:
      DOI: 10.1111/php.12769
       
  • Information for authors
    • PubDate: 2017-04-04T07:44:47.124548-05:
      DOI: 10.1002/pssa.201770125
       
  • Targeting Photochemical Scalpels or Lancets in the PDT Field - The
           Photochemist's Role
    • Authors: Stefano Protti; Angelo Albini, Radhika Viswanathan, Alexander Greer
      Abstract: This review covers photochemical approaches aimed at supplementing surgical instruments with hand-held photodynamic therapy (PDT) instruments. PDT is not widely used in hospitals, because of the laser equipment and expertise needed, and because insurance policies often do not cover the procedure. Accordingly, this review focuses on advances in photochemistry, photophysics, nanotechnology and miniaturization techniques that may likely inspire the use of hand-held instruments in PDT. A takeaway point is that the advent of photochemical scalpels or lancets that deliver reactive oxygen species (ROS) on site may better equip medical practitioners and allow for eradication of tumors or infections in general. Specifically, the review is divided into several sections: sensitizer types, multiphoton and plasmonic topics, sensitizer delivery, light delivery, dosimetry, fiber optics and hand-held implements in PDT.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-04T05:30:58.563328-05:
      DOI: 10.1111/php.12766
       
  • Novel Osmium-based Coordination Complexes as Photosensitizers for
           Panchromatic Photodynamic Therapy
    • Authors: Savo Lazic; Pavel Kaspler, Ge Shi, Susan Monro, Tariq Sainuddin, Sarah Forward, Kamola Kasimova, Robie Hennigar, Arkady Mandel, Sherri McFarland, Lothar Lilge
      Abstract: Cancer remains a major global malaise requiring the advent of new, efficient, and low-cost treatments. Photodynamic therapy, which combines a photosensitizer and photons to produce cytotoxic reactive oxygen species, has been established as an effective cancer treatment but has yet to become mainstream. One of the main limitations has been the paucity of photosensitizers that are effective over a wide range of wavelengths, can exert their cytotoxic effects in hypoxia, are easily synthesized, and produce few if any side effects. To address these shortfalls, three new osmium-based photosensitizers (TLD1822, TLD1824, and TLD1829) were synthesized and their photophysical and photobiological attributes determined. These photosensitizers are panchromatic (i.e., black absorbers), activatable from 200 to 900 nm, and have strong resistance to photobleaching. In vitro studies show PDT efficacy with both red and near infrared light in normoxic and hypoxic conditions, which translated to in vivo efficacy of TLD1829 in a subcutaneous murine colon cancer model.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-03T13:30:38.049001-05:
      DOI: 10.1111/php.12767
       
  • Naproxen Inhibits UVB-induced Basal Cell and Squamous Cell Carcinoma
           Development in Ptch1+/-/SKH-1 hairless mice
    • Authors: Sandeep C. Chaudhary; Mohammad Waseem, Mehtab Rana, Hui Xu, Levy Kopelovich, Craig A. Elmets, Mohammad Athar
      Abstract: Naproxen possesses anti-proliferative and pro-apoptotic effects besides its known anti-inflammatory functions. Here, we demonstrate the anti-cancer effects of naproxen against UVB-induced BCCs and SCCs in a highly susceptible murine model of UVB carcinogenesis. Naproxen significantly inhibited UVB-induced BCCs and SCCs in this model. Tumor number and volume were significantly decreased (p
      PubDate: 2017-03-22T12:05:24.656823-05:
      DOI: 10.1111/php.12758
       
  • The Phototoxic Potential of the Flavonoids, Taxifolin and Quercetin
    • Authors: Alena Rajnochová Svobodová; Alena Ryšavá, Michaela Psotová, Pavel Kosina, Bohumil Zálešák, Jitka Ulrichová, Jitka Vostálová
      Abstract: Quercetin, one of the most abundant polyphenols in the plant kingdom has been shown to be photodegraded on exposure to UV light. Despite the fact, it is a component of several dermatological preparations. Its phototoxic potential has not been evaluated to date. The aim of this study was to assess whether photo-induced degradation of quercetin is linked to phototoxic effects on living cells. Its dihydro derivative, taxifolin was included in the study. For evaluation, the 3T3 Neutral Red Uptake Phototoxicity Test according to OECD TG 432, was used. To better approximate human skin, HaCaT keratinocytes, normal human epidermal keratinocytes and dermal fibroblasts were used, apart from the Balb/c 3T3 cell line. Quercetin showed a dose-dependent photodegradation in aqueous and organic environments and a phototoxic effect on all used cells. Quercetin pre-treatment and following UVA exposure resulted in increased reactive oxygen species production and intracellular GSH level depletion in human dermal fibroblasts. Taxifolin was found completely non-phototoxic and photostable. As only in vitro methodology was used further studies using 3D skin models and/or human volunteers are needed to confirm whether exposure to sunlight, tanning sunbeds and/or phototherapy in people using cosmetics containing quercetin, is a health risk.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-16T23:25:28.479225-05:
      DOI: 10.1111/php.12755
       
  • Skin Erythema, Pigmentation and Hydration Kinetics after Ultraviolet
           Radiation-induced Photodamage in Southern Chinese Women
    • Authors: MiaoJian Wan; Rong Hu, Xiaoyuan Xie, Zijian Gong, Jinling Yi, Haiyan Chen, Lin Xie, Xiaomin Guan, Lei Guan, Wei Lai
      Abstract: Although there have been some studies about changes of skin erythema and pigmentation following ultraviolet radiation in other races, the relevant data in Chinese have never been achieved. Thus we evaluated the long-time course of skin erythema, pigmentation and hydration changes after different doses of solar-simulated ultraviolet (SSUV) irradiation in 26 Chinese women for 168 days. The erythema index increased abruptly and peaked during 3 days of SSUV exposure, then slowly returned to the baseline level starting at day 7 and completely recovered during 168-day course of this study only in one minimal erythema doses (MED) SSUV irradiation. The melanin index started to slowly increase at day 3 of SSUV exposure, peaking at day 14 and gradually returned to the baseline level thereafter, but did not return to the baseline level during 168-day course in all doses. Skin hydration slowly declined at day 3 of exposure, hitting the lowest point at day 7, then slowly recovered starting at day 14 and completely returned to the baseline level at day 28 only in 1.5MED. These results will serve as baseline data on Chinese skin and provide useful references for the treatment of serious skin photodamage in Chinese.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-15T01:50:36.871093-05:
      DOI: 10.1111/php.12752
       
  • Photochemical Immobilization of Polymers on a Surface: Controlling Film
           Thickness and Wettability
    • Authors: Gregory T. Carroll; Nicholas J. Turro, Angela Mammana, Jeffrey T. Koberstein
      Abstract: In this manuscript we demonstrate the control of film thickness and surface wettability in the photochemical immobilization of poly (vinyl alcohol) (PVA) to a self-assembled monolayer (SAM) containing a phthalimide chromophore. Surface attachment is characterized by ellipsometry and contact angle measurements. The wettability of the resulting films is shown to depend on the chemical composition of the polymer. The film thickness is shown to depend on the irradiation time and molecular weight of the polymer. Using a photo-mask, micro-patterns of polymers can be grafted to the SAM. The photo-patterned surface can be “developed” by coating with a thin layer of a mixture containing poly (styrene) (PS) and triphenylsulfonium triflate.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-15T01:45:22.696003-05:
      DOI: 10.1111/php.12751
       
  • Melanoma Chemoprevention: Current Status and Future Prospects
    • Authors: Gagan Chhabra; Mary Ann Ndiaye, Liz Mariely Garcia-Peterson, Nihal Ahmad
      Abstract: The incidence of skin cancers, both non-melanoma as well as melanoma, are increasing in the United States. The ultraviolet radiation, mainly from sun, is considered the major cause for these neoplasms. While non-melanoma skin cancers are far more numerous, melanoma remains the most challenging. This is because melanoma can become extremely aggressive and its incidence is increasing worldwide due to lack of effective early detection, as well as disease recurrence, following both surgery and chemotherapy. Therefore, in addition to better treatment options, newer means are required to prevent melanomas from developing. Chemoprevention is a reasonable cost-effective approach to prevent carcinogenesis by inhibiting the processes of tumor initiation, promotion and progression. Melanoma is a progressive disease, which makes it very suitable for chemopreventive interventions, by targeting the processes and molecular pathways involved in the progression of melanoma. This review discusses the roles of various chemopreventive agents such as NSAIDs, statins, vitamins and dietary agents in melanoma and highlights current advancements and our perspective on future of melanoma chemoprevention. Although considerable preclinical data suggest that melanoma may be prevented or delayed by a numerous chemopreventive agents, we realize there are insufficient clinical studies evaluating their efficacy and long-term safety for human use.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-15T01:30:30.413457-05:
      DOI: 10.1111/php.12749
       
  • Calcium Control of the Sign of Phototaxis in Brown Algal Gametes of Mutimo
           cylindricus
    • Authors: Nana Kinoshita; Chikako Nagasato, Taizo Motomura
      Abstract: Brown algal swarmers usually exhibit positive or negative phototaxis. Such behaviours influence the increasing or decreasing dispersal distance or colonization on the new substratum. We confirmed that the sign of phototaxis (negative or positive) in male gametes of Mutimo cylindricus was affected by extracellular Ca2+ influx through Ca2+ channels. Under the control condition (10-2 M [Ca2+]), male gametes swimming with a helical rotation of their cell body mostly showed positive phototaxis. At 10-3 M [Ca2+], more than half of the male gametes showed positive phototaxis, whereas the others showed negative phototaxis. From 10-4–10-5 M [Ca2+], the phototactic sign changed to negative. When these negative phototactic gametes were transferred back to the control condition, the phototactic sign reverted to positive. At 10-6 M [Ca2+], some of male gametes showed negative phototaxis, but most showed no phototaxis or flagellar beating. Lanthanum, a Ca2+ channel blocker, affected the sign of phototaxis at 10-4 M [La3+] under 10-2 M [Ca2+], and male gametes mostly showed negative phototaxis. A further increase in [La3+] inhibited phototaxis and flagellar beating. These results pointed out the involvement of Ca2+ channels that were blocked by La3+ in phototaxis and flagellar beating.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-15T01:30:25.621746-05:
      DOI: 10.1111/php.12748
       
  • Phytochemicals for the Prevention of Photocarcinogenesis
    • Authors: Mary K. Montes de Oca; Ross L. Pearlman, Sarah F. McClees, Rebecca Strickland, Farrukh Afaq
      Abstract: Ultraviolet (UV) exposure has an array of damaging effects and is the main cause of skin cancer in humans. Nonmelanoma skin cancer (NMSC), including basal cell carcinoma and squamous cell carcinoma, is the most common type of cancer. Incidence of NMSC has increased due to greater UV radiation, increased life expectancy and other changes in lifestyle; the annual cost of skin cancer treatment in the United States has increased concurrently to around eight billion dollars. Because of these trends, novel approaches to skin cancer prevention have become an important area of research to decrease skin cancer morbidity and defray the costs associated with treatment. Chemoprevention aims to prevent or delay the development of skin cancer through the use of phytochemicals. Use of phytochemicals as chemopreventive agents has gained attention due to their low toxicity and anticarcinogenic properties. Phytochemicals also exhibit antioxidant, anti-inflammatory and antiproliferative effects which support their use as chemopreventive agents, particularly for skin cancer. Preclinical and human studies have shown that phytochemicals decrease UV-induced skin damage and photocarcinogenesis. In this review article, we discuss the selected phytochemicals that may prevent or delay UV-induced carcinogenesis and highlight their potential use for skin protection.Ultraviolet (UV) exposure is the main cause of human skin cancer due to its damaging effects on skin cells. Chemoprevention prevents or delays the development of skin cancer through the use of phytochemicals. Phytochemicals impede the damaging effects of UV radiation and may lead to inhibition of photocarcinogenesis.
      PubDate: 2017-03-14T13:35:28.021513-05:
      DOI: 10.1111/php.12711
       
  • Ultraviolet Radiation-Induced Downregulation of SERCA2 Mediates Activation
           of NLRP3 Inflammasome in Basal Cell Carcinoma
    • Authors: Israr Ahmad; Kashiff M. Muneer, Michelle E. Chang, Hana M. Nasr, Jacqueline M. Clay, Conway C. Huang, Nabiha Yusuf
      Abstract: Basal cell carcinomas (BCCs) account for majority of skin malignancies in the United States. The incidence of BCCs is strongly associated with exposure of ultraviolet (UV) radiation. Nucleotide-binding domain, leucine-rich-repeat-containing family, pyrin domain-containing 3 (NLRP3) inflammasome plays an important role in innate immune responses. Different stimuli such as toxins, microorganisms and particles released from injured cells activate the NLRP3 inflammasome. Activated NLRP3 results in activation of caspase-1, which cleaves pro-IL-1β to active IL-1β. In this study, we have shown that NLRP3 is expressed in human basal cell carcinomas. The proximal steps in activation of NLRP3 inflammasome are not well understood. Here, we have attempted to elucidate a critical role for Ca2+ mobilization in activation of the NLRP3 inflammasome by UVB exposure using HaCaT keratinocytes. We have demonstrated that UVB exposure blocks Ca2+ mobilization by downregulating the expression of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2), a component of store-operated Ca2+ entry that leads to activation of the NLRP3 inflammasome.Critical role for Ca2+ mobilization in activation of the nucleotide-binding domain, leucine-rich-repeat-containing family, pyrin domain-containing 3 (NLRP3) inflammasome. Ultraviolet (UV) B exposure blocks Ca2+ mobilization by downregulating the expression of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2), a component of store-operated Ca2+ entry (SOCE) that leads to activation of the NLRP3 inflammasome.
      PubDate: 2017-03-06T03:41:36.853784-05:
      DOI: 10.1111/php.12725
       
  • Silibinin Treatment Inhibits the Growth of Hedgehog Inhibitor-Resistant
           Basal Cell Carcinoma Cells via Targeting EGFR-MAPK-Akt and Hedgehog
           Signaling
    • Authors: Arpit Dheeraj; Cynthia M. Rigby, Cindy L. O'Bryant, Chapla Agarwal, Rana P. Singh, Gagan Deep, Rajesh Agarwal
      Abstract: Basal cell carcinoma (BCC) is the most common skin malignancy. Deregulated hedgehog signaling plays a central role in BCC development; therefore, hedgehog inhibitors have been approved to treat locally advanced or metastatic BCC. However, the development of resistance to hedgehog inhibitors is the major challenge in effective treatment of this disease. Herein, we evaluated the efficacy of a natural agent silibinin to overcome resistance with hedgehog inhibitors (Sant-1 and GDC-0449) in BCC cells. Silibinin (25–100 μm) treatment for 48 h strongly inhibited growth and induced death in ASZ001, Sant-1-resistant (ASZ001-Sant-1) and GDC-0449-resistant (ASZ001-GDC-0449) BCC cells. Furthermore, colony-forming ability of ASZ001, ASZ001-Sant-1 and ASZ001-GDC-0449 cells was completely inhibited by silibinin treatment. Molecular analysis showed that silibinin treatment decreased the level of phosphorylated EGFR (Tyrosine 1173) and total EGFR in ASZ001-Sant-1 cells, key signaling molecules responsible for BCC resistance toward hedgehog inhibitors. Further, silibinin treatment decreased the phosphorylated Akt (Serine 473), phosphorylated ERK1/2 (Threonine 202/Tyrosine 204), cyclin D1 and Gli-1 level but increased the SUFU expression in ASZ001-Sant-1-resistant cells. Silibinin treatment of ASZ001-Sant-1-resistant cells also decreased bcl-2 but increased cleaved caspase 3 and PARP cleavage, suggesting induction of apoptosis. Together, these results support silibinin use to target hedgehog inhibitor-resistant BCC cells.In this study, we evaluated the efficacy of a natural agent silibinin to overcome resistance against hedgehog inhibitors (Sant-1 or GDC-0449) in basal cell carcinoma (BCC) cells. The silibinin treatment strongly inhibited the cell growth and induced death in ASZ001, ASZ001-Sant-1-resistant and ASZ001-GDC-0449-resistant BCC cells. Colony-forming ability of the hedgehog inhibitor-resistant BCC cells was completely inhibited with silibinin treatment. Mechanistic studies revealed that silibinin inhibits EGFR-MAPK-Akt and hedgehog signaling in resistant BCC cells. Silibinin treatment also targeted the key cell death-associated molecules in the resistant BCC cells.
      PubDate: 2017-03-06T03:41:29.654018-05:
      DOI: 10.1111/php.12727
       
  • CeO2/Bi2WO6 Heterostructured Microsphere with Excellent
           Visible-light-driven Photocatalytic Performance for Degradation of
           Tetracycline Hydrochloride
    • Authors: Fengjun Zhang; Shuang Zou, Tianye Wang, Yuxi Shi, Peng Liu
      Abstract: CeO2/Bi2WO6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines were successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO2/Bi2WO6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi2WO6 in both the degradation of Tetracycline hydrochloride (TCH) and Rhodamine B (RhB) under visible-light irradiation. The 1CeO2/2Bi2WO6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO2 and Bi2WO6 in the as-prepared microspheres, so that the separation efficiency of photogenerated electrons and holes were dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO2 could significantly enhance the photocatalytic activity of CeO2/Bi2WO6 heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO2/Bi2WO6 with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines waste water from pharmaceutical factory.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-06T02:55:41.678243-05:
      DOI: 10.1111/php.12747
       
  • UVB-generated Microvesicle Particles: A Novel Pathway by Which a
           Skin-specific Stimulus Could Exert Systemic Effects
    • Authors: Katherine Fahy; Langni Liu, Christine M. Rapp, Christina Borchers, Ji C. Bihl, Yanfang Chen, Richard Simman, Jeffrey B. Travers
      Abstract: Ultraviolet B radiation (UVB) exerts profound effects on human skin. Much is known regarding the ability of UVB to generate a plethora of bioactive agents ranging from cytokines and other bioactive proteins, lipid mediators and microRNAs. It is presumed that these agents are in large part responsible for the effects of UVB, which is only absorbed appreciably in the epidermis. However, the exact mechanism by which these bioactive agents can leave the epidermis are as yet unclear. This review addresses the potential role of microvesicle particles (MVP) as UVB signaling agents through transmitting biologic mediators. New data are provided that UVB treatment of human skin explants also generates MVP production. We hypothesize that UVB production of MVPs (UVB-MVP) could serve this important function of transmitting keratinocyte-derived bioactive agents. Moreover, we propose that UVB-MVP formation involves the lipid mediator platelet-activating factor. This novel pathway has the potential to be exploited pharmacologically to modulate UVB effects.UVB generates microvesicle particles through involvement of the lipid mediator platelet-activating factor (PAF). The cartoon depicts theoretical pathway by which UVB-induced reactive oxygen species (ROS) which generate PAF agonists that then trigger microvesicle particle release. This cartoon also suggests potential targets by which this pathway can be modulated.
      PubDate: 2017-03-02T06:25:57.5006-05:00
      DOI: 10.1111/php.12703
       
  • FRET in a Synthetic Flavin- and Bilin-binding Protein
    • Authors: Julian Simon; Aba Losi, Kai-Hong Zhao, Wolfgang Gärtner
      Abstract: The last decade has seen development and application of a large number of novel fluorescence-based techniques that have revolutionized fluorescence microscopy in life sciences. Preferred tags for such applications are genetically encoded fluorescent proteins (FP), mostly derivatives of the green fluorescent protein (GFP). Combinations of FPs with wavelength-separated absorption/fluorescence properties serve as excellent tools for molecular interaction studies, for example, protein–protein complexes or enzyme–substrate interactions, based on the FRET phenomenon (Förster resonance energy transfer). However, alternatives are requested for experimental conditions where FP proteins or FP couples are not or less efficiently applicable. We here report as a “proof of principle” a specially designed, non-naturally occurring protein (LG1) carrying a combination of a flavin-binding LOV- and a photochromic bilin-binding GAF domain and demonstrate a FRET process between both chromophores.A ‘home-made’ FRET couple: Energy transfer is demonstrated between a flavin-binding LOV domain and a photochromic bilin-binding GAF domain. A FRET process between both chromophores is observed over a distance of 5–7 nm with a transfer efficiency of maximally 40%.
      PubDate: 2017-03-01T07:02:00.200836-05:
      DOI: 10.1111/php.12707
       
  • Elucidation of Binding Mechanism of Photodynamic Therapeutic Agent
           Toluidine Blue O with Chicken Egg White Lysozyme by Spectroscopic and
           Molecular Dynamics Studies
    • Authors: Shanmugaraj Krishnamoorthy; Umadevi Palanivel, Senthilkumar Lakshmipathi, Ilanchelian Malaichamy
      Abstract: The nature of binding mechanism of toluidine blue O (TBO) with chicken egg white lysozyme was studied comprehensively by various spectroscopic and computational methods. Both steady state and time resolved fluorescence studies unambiguously point to the prevalence of static quenching mechanism in lysozyme-TBO system. Thermodynamic parameters revealed that the association of TBO with lysozyme was a spontaneous process in which hydrophobic and hydrogen bond interactions played a pivotal role in the binding process. The secondary and tertiary conformational changes in lysozyme in the presence of TBO were unraveled using absorption, Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) techniques. Molecular docking studies of lysozyme-TBO system substantiated the findings of site marker experiment and revealed TBO adjacent to Trp-63 and Trp-108 residues of lysozyme. Molecular dynamics (MD) simulation studies of lysozyme-TBO system indicate a stable and effective complexation of TBO with lysozyme. It is hoped that the results presented here will enable further understanding of TBO toxicity.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-01T01:55:25.875691-05:
      DOI: 10.1111/php.12744
       
  • The B6-vitamer Pyridoxal is a Sensitizer of UVA-induced Genotoxic Stress
           in Human Primary Keratinocytes and Reconstructed Epidermis
    • Authors: Rebecca Justiniano; Joshua D. Williams, Jessica Perer, Anh Hua, Jessica Lesson, Sophia L. Park, Georg T. Wondrak
      Abstract: UVA-driven photooxidative stress in human skin may originate from excitation of specific endogenous chromophores acting as photosensitizers. Previously, we have demonstrated that 3-hydroxypyridine-derived chromophores including B6-vitamers (pyridoxine, pyridoxamine and pyridoxal) are endogenous photosensitizers that enhance UVA-induced photooxidative stress in human skin cells. Here, we report that the B6-vitamer pyridoxal is a sensitizer of genotoxic stress in human adult primary keratinocytes (HEKa) and reconstructed epidermis. Comparative array analysis indicated that exposure to the combined action of pyridoxal and UVA caused upregulation of heat shock (HSPA6, HSPA1A, HSPA1L, HSPA2), redox (GSTM3, EGR1, MT2A, HMOX1, SOD1) and genotoxic (GADD45A, DDIT3, CDKN1A) stress response gene expression. Together with potentiation of UVA-induced photooxidative stress and glutathione depletion, induction of HEKa cell death occurred only in response to the combined action of pyridoxal and UVA. In addition to activational phosphorylation indicative of genotoxic stress [p53 (Ser15) and γ-H2AX (Ser139)], comet analysis indicated the formation of Fpg-sensitive oxidative DNA lesions, observable only after combined exposure to pyridoxal and UVA. In human reconstructed epidermis, pyridoxal preincubation followed by UVA exposure caused genomic oxidative base damage, procaspase 3 cleavage and TUNEL positivity, consistent with UVA-driven photooxidative damage that may be relevant to human skin exposed to high concentrations of B6-vitamers.UVA-driven photooxidative stress in human skin may originate from excitation of specific endogenous chromophores acting as photosensitizers. Here, evidence is presented suggesting that the B6-vitamer pyridoxal is a sensitizer of genotoxic stress in human adult primary keratinocytes. In human reconstructed epidermis, pyridoxal pre-incubation followed by UVA exposure caused genomic oxidative base damage (8-oxo-dG), procaspase 3 cleavage and TUNEL positivity, consistent with UVA-driven photooxidative damage that may be relevant to human skin exposed to high concentrations of B6-vitamers.
      PubDate: 2017-02-28T01:55:46.315205-05:
      DOI: 10.1111/php.12720
       
  • Damaging Effects of Ultraviolet Radiation on the Cornea
    • Authors: Naomi C. Delic; J. Guy Lyons, Nick Di Girolamo, Gary M. Halliday
      Abstract: The cornea sits at the anterior aspect of the eye and, like the skin, is highly exposed to ultraviolet radiation (UVR). The cornea blocks a significant proportion of UVB from reaching the posterior structures of the eye. However, UVA can penetrate the full thickness of the cornea, even reaching the anterior portion of the lens. Epidemiological data indicate that UVR is a contributing factor for a multitude of diseases of the cornea including pterygium, photokeratitis, climatic droplet keratopathy and ocular surface squamous neoplasia (OSSN), although the pathogenic mechanisms of each require further elucidation. UVR is a well-known genotoxic agent, and its effects have been well characterized in organs such as the skin. However, we are only beginning to identify its effects on the cornea, such as the UVR signature C T and CC TT transversions identified by sequencing and increased proliferative and shedding rates in response to UVR exposure. Alarmingly, a single low-dose exposure of UVR to the cornea is sufficient to elicit genetic, molecular and cellular changes, supporting the consideration of using protective measures, such as wearing sunglasses when outdoors. The aim of this review was to describe the adverse effects of UVR on the cornea.The clarity and structural integrity of the cornea is essential for proper vision. It is highly exposed to sunlight and therefore susceptible to ultraviolet radiation (UVR)-induced damage. We have recently used a mouse model containing fluorescent probes in stem cells in the cornea. A single low dose of UVB provoked an increase in the epithelial progeny of the stem cells in the limbus being forced centripetally towards the center of the cornea, creating a spoke like appearance of the labeled progeny growing toward the center of the cornea. This review highlights the damaging effects of UVR on the cornea.
      PubDate: 2017-02-28T01:55:33.443453-05:
      DOI: 10.1111/php.12686
       
  • Schoolyard Shade and Sun Exposure: Assessment of Personal Monitoring
           During Children's Physical Activity
    • Authors: Jennifer K. Vanos; Grant R. McKercher, Kylie Naughton, Marc Lochbaum
      Abstract: Childhood exposure to ultraviolet radiation (UVR) is a major risk factor for the development of melanoma later in life. However, it is challenging to accurately determine personal outdoor exposure to UVR, specifically erythemally weighted UVR (UVEry), due to technological constraints, variable time–activity patterns, and the influence of outdoor environmental design. To address this challenge, this study utilized mobile and stationary techniques to examine the UVEry exposures of 14 children in a schoolyard in Lubbock, TX, in spring 2016. The aims of the study were to examine the influence of artificial shade on personal UVEry exposures and to assess full sun exposure ratios (ERs) within the same playground microenvironment. On average, personal wrist dosimeters worn during play in the sun measured 18% of the total onsite UVEry measured by a stationary UV pyranometer. Shade was found to significantly reduce the personal UVEry exposures by 55%, UVB280–315 nm exposures by 91%, and the overall solar radiation by 84%. Substantial benefits can be garnered through focused design of children's recreational space to utilize shade—both natural and artificial—to reduce UVR exposures during play, and to extend safe outdoor stays. Finally, although the wrist is a practical location for a dosimeter, it often underestimates full exposures, particularly during physical activity.The use of personal UV dosimeters allows for the detection of individual erythemal UV exposures. Results show that substantial benefits can be garnered through focused bioclimatic design of children's recreational space to utilize shade, both natural and artificial, to reduce UV exposures during play, and to extend safe outdoor stays.
      PubDate: 2017-02-24T13:40:32.134613-05:
      DOI: 10.1111/php.12721
       
  • A Comparison of Dose Metrics to Predict Local Tumor Control for
           Photofrin-mediated Photodynamic Therapy
    • Authors: Haixia Qiu; Michele M. Kim, Rozhin Penjweini, Jarod C. Finlay, Theresa M. Busch, Tianhao Wang, Wensheng Guo, Keith A. Cengel, Charles B. Simone, Eli Glatstein, Timothy C. Zhu
      Abstract: This preclinical study examines light fluence, photodynamic therapy (PDT) dose and “apparent reacted singlet oxygen,” [1O2]rx, to predict local control rate (LCR) for Photofrin-mediated PDT of radiation-induced fibrosarcoma (RIF) tumors. Mice bearing RIF tumors were treated with in-air fluences (50–250 J cm−2) and in-air fluence rates (50–150 mW cm−2) at Photofrin dosages of 5 and 15 mg kg−1 and a drug-light interval of 24 h using a 630-nm, 1-cm-diameter collimated laser. A macroscopic model was used to calculate [1O2]rx and PDT dose based on in vivo explicit dosimetry of the drug concentration, light fluence and tissue optical properties. PDT dose and [1O2]rx were defined as a temporal integral of drug concentration and fluence rate, and singlet oxygen concentration consumed divided by the singlet oxygen lifetime, respectively. LCR was stratified for different dose metrics for 74 mice (66 + 8 control). Complete tumor control at 14 days was observed for [1O2]rx ≥ 1.1 mm or PDT dose ≥1200 μm J cm−2 but cannot be predicted with fluence alone. LCR increases with increasing [1O2]rx and PDT dose but is not well correlated with fluence. Comparing dosimetric quantities, [1O2]rx outperformed both PDT dose and fluence in predicting tumor response and correlating with LCR.This preclinical study examines light fluence, photodynamic therapy (PDT) dose and “apparent reacted singlet oxygen,” [1O2]rx, to predict local control rate (LCR) for Photofrin-mediated PDT of radiation-induced fibrosarcoma (RIF) tumors. LCR was stratified for different dose metrics for 74 mice (66 + 8 control). Complete tumor control at 14 days was observed for [1O2]rx ≥ 1.1 mm or PDT dose ≥1200 µm J cm−2 but cannot be predicted with fluence alone. LCR increases with increasing [1O2]rx and PDT dose but is not well correlated with fluence. Comparing dosimetric quantities, [1O2]rx outperformed both PDT dose and fluence in predicting tumor response and correlating with LCR.
      PubDate: 2017-02-22T14:15:41.481931-05:
      DOI: 10.1111/php.12719
       
  • UVA Light-mediated Ascorbate Oxidation in Human Lenses
    • Authors: Stefan Rakete; Ram H. Nagaraj
      Abstract: Whether ascorbate oxidation is promoted by UVA light in human lenses and whether this process is influenced by age and GSH levels are not known. In this study, we used paired lenses from human donors. One lens of each pair was exposed to UVA light, whereas the other lens was kept in the dark for the same period of time as the control. Using LC-MS/MS analyses, we found that older lenses (41–73 years) were more susceptible to UVA-induced ascorbate oxidation than younger lenses (18–40 years). Approximately 36% of the ascorbate (relative to control) was oxidized in older lenses compared to ~16% in younger lenses. Furthermore, lenses with higher levels of GSH were less susceptible to UVA-induced ascorbate oxidation compared to those with lower levels, and this effect was not dependent on age. The oxidation of ascorbate led to elevated levels of reactive α-dicarbonyl compounds. In summary, our study showed that UVA light exposure leads to ascorbate oxidation in human lenses and that such oxidation is more pronounced in aged lenses and is inversely related to GSH levels. Our findings suggest that UVA light exposure could lead to protein aggregation through ascorbate oxidation in human lenses.This study shows that UVA light (320–400 nm) can oxidize human lens ascorbate and decrease glutathione levels. The combined effects are a decline in ascorbate reduction and an increase in the production of α-dicarbonyl compounds. The latter can react with lens proteins to form advanced glycation end products (AGEs) that can cross-link proteins and could contribute to lens aging and cataract formation.
      PubDate: 2017-02-22T14:15:31.512279-05:
      DOI: 10.1111/php.12717
       
  • Novel Bi2WO6 coupled Fe3O4 Magnetic Photocatalysts: Preparation,
           Characterization and Photodegradation of Tetracycline Hydrochloride
    • Authors: Tianye Wang; Shuang Zhong, Shuang Zou, Fuhuan Jiang, Limin Feng, Xiaosi Su
      Abstract: Novel Bi2WO6 coupled Fe3O4 magnetic photocatalysts with excellent and stable photocatalytic activity for degrading tetracycline hydrochloride and RhB were successfully synthesized via a facile solvothermal route. Through the characterization of the as-prepared magnetic photocatalysts by XRD, SEM, TEM, XPS, UV-vis diffuse reflectance spectra, it was found that the as-prepared magnetic photocatalysts were synthesized by the coupling of Bi2WO6 and Fe3O4, and introduction of appropriated Fe3O4 can improved nanospheres morphology and visible-light response. Among them, BFe2 (0.16% Fe3O4) exhibited the best photocatalytic activity for degradation of TCH, reaching 81.53% after 90min. Meanwhile, the as-prepared magnetic photocatalysts showed great separation and recycle property. Moreover, the results of EIS demonstrated that the well conductivity of Fe3O4 can promoted photogenerated charge carriers transfer and inhibited recombination of electron-hole pairs, so that Bi2WO6/Fe3O4 exhibited enhanced photocatalytic activity on degradation of TCH and RhB. Hence, this work provides a principle method to synthesize Bi2WO6/Fe3O4 with excellent photocatalytic performance for actual application, in addition, it showed that introduction of Fe3O4 not only can provide magnetism, but also can enhance photocatalytic activity of Bi2WO6/Fe3O4 magnetic photocatalysts.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-15T16:45:28.60909-05:0
      DOI: 10.1111/php.12739
       
  • Enhancement of the Efficacy of Photodynamic Inactivation of Candida
           albicans with the Use of Biogenic Gold Nanoparticles
    • Authors: Irena Maliszewska; Barbara Lisiak, Katarzyna Popko, Katarzyna Matczyszyn
      Abstract: This study reports on successful photodynamic inactivation of planktonic and biofilm cells of Candida albicans using Rose Bengal (RB) in combination with biogenic gold nanoparticles synthesized by the cell-free filtrate of Penicillium funiculosum BL1 strain. Monodispersed colloidal gold nanoparticles coated with proteins were characterized by a number of techniques including SEM-EDS, TEM, UV-Vis absorption and fluorescence spectroscopy, as well as Fourier transform infrared spectroscopy to be 24±3 nm spheres coated with proteins. A Xe-lamp (output power of 20mW, delivering intensity of 53 mW cm−2) was used as a light source. The most effective reduction in the number of planktonic cells was found after 30 minutes of Xe lamp light irradiation (95.4 J cm−2) and was 4.89 log10 that is 99.99% kill compared with 2.19 log10 or 99.37% for RB. The biofilm cells were more resistant to photodynamic inactivation and the highest effective reduction in the number of cells was found after 30 minutes of irradiation in the presence of the RB-gold nanoparticles mixture and was 1.53 log10, that is 97.04% kill compared with 0.6 log10 or 74.73% for RB.The probable mechanism of enhancement of RB-mediated photodynamic fungicidal efficacy against Candida albicans in the presence of biogenic gold nanoparticles is discussed leading to the conclusion that this process may have a multifaceted character.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-12T20:20:28.272401-05:
      DOI: 10.1111/php.12733
       
  • Antigenotoxic Effect Against Ultraviolet Radiation Induced DNA Damage of
           the Essential Oils from Lippia Species
    • Authors: Nathalia Quintero Ruiz; Yuri Cordoba Campo, Elena E. Stashenko, Jorge Luis Fuentes
      Abstract: The antigenotoxicity against ultraviolet radiation (UV) -induced DNA damage of essential oils (EO) from Lippia species was studied using SOS Chromotest. Based on the minimum concentration that significantly inhibits genotoxicity, the genoprotective potential of EO from highest to lowest was L. alba, citral -rich chemotype (RC) > L. graveolens, thymol-RC ≈ L. origanoides, thymol-RC ≈ L. origanoides, carvacrol-RC > L. micromera, thymol-RC ≈ L. citriodora, citral-RC > L. alba, myrcenone-RC > L. alba, carvone-RC > L. origanoides, p-cymene/phellandrene-RC. EO from L. dulcis, trans-β-caryophyllene-RC did not reduce the DNA damage. A gas chromatography with flame ionization detection analysis (GC-FID) was conducted to evaluate the solubility of the major EO constituents under our experimental conditions. GC-FID analysis showed that, at least partially, major EO constituents were water-soluble and therefore, they were related with the antigenotoxicity detected for EO. Constituents such as p-cymene, geraniol, carvacrol, thymol, citral and 1,8-cineole showed antigenotoxicity. The antioxidant activity of EO constituents was also determined using the oxygen radical antioxidant capacity (ORAC) assay. The results shown that the antigenotoxicity of the EO constituents was unconnected with their antioxidant activity. The antigenotoxicity to different constituent binary mixtures suggest that synergistic effects can occur in some of the studied EO.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-08T13:00:41.334056-05:
      DOI: 10.1111/php.12735
       
  • Crosstalk Among UV-Induced Inflammatory Mediators, DNA Damage and
           Epigenetic Regulators Facilitates Suppression of the Immune System
    • Authors: Ram Prasad; Santosh K. Katiyar
      Abstract: The suppression of the immune system by overexposure to ultraviolet (UV) radiation has been implicated in the initiation and progression of photocarcinogenesis. Numerous changes occur in the skin on UVB exposure, including the generation of inflammatory mediators, DNA damage, epigenetic modifications, and migration and functional alterations in the antigen-presenting dendritic cells. Although each of these alterations can elicit a cascade of events that have the potential to modulate immune sensitivity alone, there is emerging evidence that there is considerable crosstalk between these cascades. The development of an understanding of UV-induced changes in the skin that culminate in UV-induced immunosuppression, which has been implicated in the risk of nonmelanoma skin cancer, as a network of events has implications for the development of more effective chemopreventive strategies. In the current review article, we discuss the evidence of interactions between the various molecular targets and signaling mechanisms associated with UV-induced immunosuppression.Crosstalk among UV radiation-induced inflammatory mediators, DNA damage and epigenetic regulators results in photo-immunosuppression. UVB radiation-induced photodamage initiates migration of antigen-presenting cells from skin to regional lymph nodes, where they present antigen to T cells in an unusual way. UVB-induced inflammatory mediators and DNA damage affect epigenetic regulators and all together play crucial roles in suppression of immune system in UV radiation-exposed mouse skin. This suppression of immune system is implicated in skin cancer risk.
      PubDate: 2017-02-06T01:50:55.81864-05:0
      DOI: 10.1111/php.12687
       
  • Photo Co-Carcinogenesis of Topically Applied Retinyl Palmitate in SKH-1
           Hairless Mice
    • Authors: Mary D. Boudreau; Frederick A. Beland, Robert P. Felton, Peter P. Fu, Paul C. Howard, Paul W. Mellick, Brett T. Thorn, Greg R. Olson
      Abstract: Cosmetic products that contain retinyl palmitate are popular as anti-aging skin treatments; however, recent studies suggest a risk for enhanced skin tumor development with topical retinyl palmitate applications and exposure to solar ultraviolet radiation (UVR). In this study, we investigated the potential of retinyl palmitate to enhance UVR-induced photo co-carcinogenesis. Groups of 36 male and 36 female SKH-1 hairless mice were exposed to simulated solar light (SSL) and treated with the control cream or creams containing retinyl palmitate, five days per week for 40 weeks. Other groups of mice were exposed to SSL and received no cream treatment or received cream treatments and were exposed to ultraviolet-A or -B. Mice were monitored for the development of skin tumors, and the incidences and multiplicities of squamous cell neoplasia were determined by histopathology. In both the absence and presence of SSL, mice administered the control cream developed skin tumors earlier and had higher incidences and multiplicities of skin squamous cell neoplasms than mice that received no cream treatment. Compared to the control cream groups, mice exposed to SSL and administered the retinyl palmitate creams demonstrated earlier onsets of skin tumors and had increased incidences and multiplicities of squamous cell skin neoplasms.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-28T02:50:51.17796-05:0
      DOI: 10.1111/php.12730
       
  • Autophagy in UV Damage Response
    • Authors: Ashley Sample; Yu-Ying He
      Abstract: UV radiation exposure from sunlight and artificial tanning beds is the major risk factor for the development of skin cancer and skin photoaging. UV-induced skin damage can trigger a cascade of DNA damage response signaling pathways, including cell cycle arrest, DNA repair and, if damage is irreparable, apoptosis. Compensatory proliferation replaces the apoptotic cells to maintain skin barrier integrity. Disruption of these processes can be exploited to promote carcinogenesis by allowing the survival and proliferation of damaged cells. UV radiation also induces autophagy, a catabolic process that clears unwanted or damaged proteins, lipids and organelles. The mechanisms by which autophagy is activated following UV exposure, and the functions of autophagy in UV response, are only now being clarified. Here, we summarize the current understanding of the mechanisms governing autophagy regulation by UV, the roles of autophagy in regulating cellular response to UV-induced photodamage and the implications of autophagy modulation in the treatment and prevention of photoaging and skin cancer.Ultraviolet (UV) radiation exposure has a number of effects on skin cells, including DNA damage, oxidative stress and apoptosis. Recent evidence has shown that autophagy is also activated by UV to mediate the complex response to UV-induced stress. This review investigates the current understanding of the role of autophagy in UV response and UV-induced disease, as well as the implications of autophagy modulation in the treatment or prevention of skin cancer.
      PubDate: 2017-01-27T10:36:37.003738-05:
      DOI: 10.1111/php.12691
       
  • Probing the Electronic Structure of Bacteriochlorophyll Radical Ions – A
           Theoretical Study of the Effect of Substituents on Hyperfine Parameters
    • Authors: Sebastian Sinnecker; Wolfgang Lubitz
      Abstract: In reaction centers (RCs) of photosynthesis a light-induced charge separation takes place creating radical cations and anions of the participating cofactors. In photosynthetic bacteria different bacteriochlorophylls (BChl) are involved in this process. Information about the electronic structure of the BChl radical cations and anions can be obtained by measuring the electron spin density distribution via the electron-nuclear hyperfine interaction using EPR and ENDOR techniques. In this communication we report isotropic hyperfine coupling constants (hfcs) of the BChl b and g radical cations and anions, calculated by density functional theory, and compare them with the more common radical ions of BChl a and with available experimental data. The observed differences in the computed hyperfine data are discussed in view of a possible distinction between these species by EPR/ENDOR methods. In addition, 14N nuclear quadrupole coupling constants (nqcs) computed for BChl a, b, g, and also for Chl a in their charge neutral, radical cation, and radical anion states are presented. These nqcs are compared with experimental values obtained by ESEEM spectroscopy on several different radical ions.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-25T02:10:41.040684-05:
      DOI: 10.1111/php.12724
       
  • Proteomic Analyses of Changes in Synechococcus sp. PCC7942 Following UV-C
           Stress
    • Authors: Xi Peng; Jie Yang, Yang Gao
      Abstract: UV-C's effects on the physiological and biochemical processes of cyanobacteria have been well characterized. However, the molecular mechanisms of cyanobacteria's tolerance to UV-C still needs further investigation. This research attempts to decode the variation in protein abundances in cyanobacteria after UV-C stress. Different expression levels of proteins in the cytoplasm of Synechococcus sp. PCC7942 under UV-C stress were investigated by using a comparative proteomic approach. Forty-seven UV-C-regulated proteins were identified by MALDI-TOF analysis and classified by Gene Ontology (GO). After studying their pathways, the proteins were mainly enriched in the groups of protein folding, inorganic ion transport, and energy production. By focusing on these areas, this study reveals the correlation between UV-C stress-responsive proteins and the physiological changes of Synechococcus sp. PCC7942 under UV-C radiation. These findings may open up new areas for further exploration in the homeostatic mechanisms associated with cyanobacteria responses to UV-C radiation.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-25T02:10:26.721776-05:
      DOI: 10.1111/php.12726
       
  • Type I and II Photosensitized Oxidation Reactions: Guidelines and
           Mechanistic Pathways
    • Authors: Maurício da Silva Baptista; Jean Cadet, Paolo Di Mascio, Ashwini A. Ghogare, Alexander Greer, Michael R. Hamblin, Carolina Lorente, Silvia Cristina Nunez, Martha Simões Ribeiro, Andrés H. Thomas, Mariana Vignoni, Tania Mateus Yoshimura
      Abstract: Here, ten guidelines are presented for a standardized definition of type I and II photosensitized oxidation reactions. Because of varied notions of reactions mediated by photosensitizers, a checklist of recommendations is provided for their definitions. Type I and type II photoreactions are oxygen-dependent and involve unstable species such as the initial formation of radical cation or neutral radicals from the substrates and/or singlet oxygen (1O2 1∆g) by energy transfer to molecular oxygen. In addition, superoxide anion radical (O2•-) can be generated by a charge transfer reaction involving O2 or more likely indirectly as the result of O2-mediated oxidation of the radical anion of type I photosensitizers. In subsequent reactions, O2•- may add and/or reduce a few highly oxidizing radicals that arise from the deprotonation of the radical cations of key biological targets. O2•- can also undergo dismutation into H2O2, the precursor of the highly reactive hydroxyl radical (•OH) that may induce delayed oxidation reactions in cells. In the second part several examples of type I and type II photosensitized oxidation reactions are provided to illustrate the complexity and the diversity of the degradation pathways of mostly relevant biomolecules upon one-electron oxidation and singlet oxygen reactions.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-13T01:55:29.576825-05:
      DOI: 10.1111/php.12716
       
  • Issue Information
    • Pages: 385 - 386
      PubDate: 2017-03-14T13:44:38.783735-05:
      DOI: 10.1111/php.12630
       
  • Bioluminescence: Basic and Applied Research.
    • Authors: Eugene S. Vysotski
      Pages: 387 - 388
      PubDate: 2017-03-14T13:44:44.049588-05:
      DOI: 10.1111/php.12736
       
  • Selected Least Studied but not Forgotten Bioluminescent Systems
    • Authors: Yuichi Oba; Cassius V. Stevani, Anderson G. Oliveira, Aleksandra S. Tsarkova, Tatiana V. Chepurnykh, Ilia V. Yampolsky
      Pages: 405 - 415
      Abstract: Bioluminescence is a form of chemiluminescence generated by luminous organisms. Luminous taxa have currently been reported from about 800 genera and probably over 10 000 species in the world. On the other hand, their bioluminescent systems, including chemical structures of luciferins/chromophores and the genes encoding luciferases/photoproteins, have been elucidated from only a few taxonomic groups, for example beetles, bacteria, dinoflagellates, ostracods and some cnidarians. Research efforts to understand unknown bioluminescence systems are being conducted around the world, and recently, for example, novel luciferin structures of luminous enchytraeid potworms and fungi were identified by the authors. In this study, we review the current status and perspectives, in the context of postgenomic era, of most likely novel but less-revealed bioluminescence systems of ten selected organisms: earthworm, parchment tubeworm, fireworm, scaleworm, limpet, millipede, brittle star, acorn worms, tunicate and shark, which indeed are the next focus of our international collaboration.Bioluminescent organisms are found in 800 genera of 13 phyla and 4 kingdoms of Life. They use ~50 distinct independently evolved bioluminescence systems comprising different chemical components: luciferin–luciferase pairs or photoproteins. Currently, the chemical structures of these components are known for only nine bioluminescence systems. Here, we review the current status and perspectives, in the context of postgenomic era, of novel bioluminescence systems of 10 selected organisms under study by the international collaborative project led by the authors: earthworm, parchment tubeworm, fireworm, scaleworm, limpet, millipede, brittle star, acorn worms, tunicate and shark.
      PubDate: 2017-02-22T14:16:16.09525-05:0
      DOI: 10.1111/php.12704
       
  • Progress in the Study of Bioluminescent Earthworms
    • Authors: Natalja S. Rodionova; Emilia Rota, Aleksandra S. Tsarkova, Valentin N. Petushkov
      Pages: 416 - 428
      Abstract: Even though bioluminescent oligochaetes rarely catch people's eyes due to their secretive lifestyle, glowing earthworms sighting reports have come from different areas on all continents except Antarctica. A major breakthrough in the research of earthworm bioluminescence occurred in the 1960s with the studies of the North American Diplocardia longa. Comparative studies conducted on 13 earthworm species belonging to six genera showed that N-isovaleryl-3-aminopropanal (Diplocardia luciferin) is the common substrate for bioluminescence in all examined species, while luciferases appeared to be responsible for the color of bioluminescence. The second momentous change in the situation has occurred with the discovery in Siberia (Russia) of two unknown luminous enchytraeids. The two bioluminescent systems belong to different types, have different spectral characteristics and localization, and different temperature and pH optima. They are unique, and this fact is confirmed by the negative results of all possible cross-reactions. The bioluminescent system of Henlea sp. comprises four essential components: luciferase, luciferin, oxygen and calcium ion. For Friderica heliota, the luminescent reaction requires five components: luciferase, luciferin, ATP, magnesium ion and oxygen. Along with luciferin, more than a dozen analogues were isolated from worm biomass. These novel peptide-like natural compounds represent an unprecedented chemistry found in terrestrial organisms.A major breakthrough in the research of earthworm bioluminescence occurred in the 1960s with the studies of the North American Diplocardia longa. A second great shift in this study has arisen with the discovery in Siberia (Russia) of two unknown luminous enchytraeids belonging to Henlea and Fridericia genera. Along with luciferin, more than a dozen analogs were isolated from Fridericia earthworm biomass. These novel peptide-like natural compounds represent an unprecedented chemistry found in terrestrial organisms.
      PubDate: 2017-02-28T01:55:42.204377-05:
      DOI: 10.1111/php.12709
       
  • Luciferin-Regenerating Enzyme Crystal Structure Is Solved but its Function
           Is Still Unclear
    • Authors: Saman Hosseinkhani; Elaheh Emamgholi Zadeh, Fatemeh Sahebazzamani, Farangis Ataei, Roohullah Hemmati
      Pages: 429 - 435
      Abstract: Contribution of luciferin-regenerating enzyme (LRE) for in vitro recycling of D-luciferin has been reported. According to crystal structure of LRE, it is a beta-propeller protein which is a type of all β-protein architecture. In this overview, reinvestigation of the luciferase-based LRE assays and its function is reported. Until now, sequence of LRE genes from four different species of firefly has been reported. In spite of previous reports, T-LRE (from Lampyris turkestanicus) was cloned and expressed in Escherichia coli as well as Pichia pastoris in a nonsoluble form as inclusion body. According to recent investigations, bioluminescent signal of soluble T-LRE–luciferase-coupled assay increased and then reached an equilibrium state in the presence of D-cysteine. In addition, the results revealed that both D- and L-cysteine in the absence of T-LRE caused a significant increase in bioluminescence intensity of luciferase over a long time. Based on activity measurements and spectroscopic results, D-cysteine increased the activity of luciferase due to its redox potential and induction of conformational changes in structure and kinetics properties. In conclusion, in spite of previous reports on the effect of LRE (at least T-LRE) on luciferase activity, most of the increase in luciferase activity is caused by direct effect of D-cysteine on structure and activity of firefly luciferase. Moreover, bioinformatics analysis cannot support the presence of LRE in peroxisome of photocytes in firefly lanterns.In luciferase–LRE-coupled assays, most of the increase in luciferase activity is caused by direct effects of D-cysteine on structural and functional properties of firefly luciferase. In spite of many studies on possible role of LRE in recycling of luciferin in vitro, low solubility of beta-rich LRE after purification and many doubts over the role of LRE in vivo remained to be investigated while the problem of crystal structure of LRE has been solved.
      PubDate: 2017-03-08T04:45:44.579492-05:
      DOI: 10.1111/php.12723
       
  • Fluorescent Protein–photoprotein Fusions and Their Applications in
           Calcium Imaging
    • Authors: Adil Bakayan; Beatriz Domingo, Cecilia F. Vaquero, Nadine Peyriéras, Juan Llopis
      Pages: 448 - 465
      Abstract: Calcium-activated photoproteins, such as aequorin, have been used as luminescent Ca2+ indicators since 1967. After the cloning of aequorin in 1985, microinjection was substituted by its heterologous expression, which opened the way for a widespread use. Molecular fusion of green fluorescent protein (GFP) to aequorin recapitulated the nonradiative energy transfer process that occurs in the jellyfish Aequorea victoria, from which these two proteins were obtained, resulting in an increase of light emission and a shift to longer wavelength. The abundance and location of the chimera are seen by fluorescence, whereas its luminescence reports Ca2+ levels. GFP-aequorin is broadly used in an increasing number of studies, from organelles and cells to intact organisms. By fusing other fluorescent proteins to aequorin, the available luminescence color palette has been expanded for multiplexing assays and for in vivo measurements. In this report, we will attempt to review the various photoproteins available, their reported fusions with fluorescent proteins and their biological applications to image Ca2+ dynamics in organelles, cells, tissue explants and in live organisms.The Ca2+-activated photoprotein aequorin has been widely used to measure Ca2+ dynamics in cells and living organisms. Chimeric fusion proteins between GFP or related fluorescent proteins and aequorin have been constructed to provide various hues for multicolor imaging or for multiplexing assays. These genetically encoded Ca2+ indicators, whose expression levels can be conveniently followed by fluorescence, show increased stability within live cells and enhanced total luminescence capacity. We review the available photoproteins, the rationale and strategies used for shifting their emission, and examples of biological applications targeted to organelles, microdomains, cell types or in vivo in transgenic organisms.
      PubDate: 2017-01-25T14:50:30.389933-05:
      DOI: 10.1111/php.12682
       
  • Cloning of the Orange Light-Producing Luciferase from Photinus
           scintillans—A New Proposal on how Bioluminescence Color is Determined
    • Authors: Bruce R. Branchini; Tara L. Southworth, Danielle M. Fontaine, Martha H. Murtiashaw, Alex McGurk, Munya H. Talukder, Rakhshi Qureshi, Deniz Yetil, Jesse A. Sundlov, Andrew M. Gulick
      Pages: 479 - 485
      Abstract: Unlike the enchanting yellow-green flashes of light produced on warm summer evenings by Photinus pyralis, the most common firefly species in North America, the orange lights of Photinus scintillans are infrequently observed. These Photinus species, and likely all bioluminescent beetles, use the same substrates beetle luciferin, ATP and oxygen to produce light. It is the structure of the particular luciferase enzyme that is the key to determining the color of the emitted light. We report here the molecular cloning of the P. scintillans luc gene and the expression and characterization of the corresponding novel recombinant luciferase enzyme. A comparison of the amino acid sequence with that of the highly similar P. pyralis enzyme and subsequent mutagenesis studies revealed that the single conservative amino acid change tyrosine to phenylalanine at position 255 accounted for the entire emission color difference. Additional mutagenesis and crystallographic studies were performed on a H-bond network, which includes the position 255 residue and five other stringently conserved beetle luciferase residues, that is proximal to the substrate/emitter binding site. The results are interpreted in the context of a speculative proposal that this network is key to the understanding of bioluminescence color determination.Photograph of a live Photinus scintillans male firefly provided by Dr. Heloise DeRosis Morgan next to an in vitro bioluminescence reaction produced by mixing its luciferase with beetle luciferin and ATP. The recombinant enzyme, which was produced from the corresponding cloned gene, produced light of identical color as that observed from the live firefly. We determined that the color of the light, which differs from the typical green, was determined by a single amino acid change. Additional mutagenesis and crystallographic results point to an active site H-bond network having a key role in color determination.
      PubDate: 2017-01-18T02:05:32.226739-05:
      DOI: 10.1111/php.12671
       
  • Tyr72 and Tyr80 are Involved in the Formation of an Active Site of a
           Luciferase of Copepod Metridia longa
    • Authors: Marina D. Larionova; Svetlana V. Markova, Eugene S. Vysotski
      Pages: 503 - 510
      Abstract: Luciferase of copepod Metridia longa (MLuc) is a naturally secreted enzyme catalyzing the oxidative decarboxylation of coelenterazine with the emission of light. To date, three nonallelic isoforms of different lengths (17–24 kDa) for M. longa luciferase have been cloned. All the isoforms are single-chain proteins consisting of a 17-residue signal peptide for secretion, variable N-terminal part and conservative C-terminus responsible for luciferase activity. In contrast to other bioluminescent proteins containing a lot of aromatic residues which are frequently involved in light emission reaction, the C-terminal part of MLuc contains only four Phe, two Tyr, one Trp and two His residues. To figure out whether Tyr residues influence bioluminescence, we constructed the mutants with substitution of Tyr to Phe (Y72F and Y80F). Tyrosine substitutions do not eliminate the ability of luciferase to bioluminescence albeit significantly reduce relative specific activity and change bioluminescence kinetics. In addition, the Tyr replacements have no effect on bioluminescence spectrum, thereby indicating that tyrosines are not involved in the emitter formation. However, as it was found that the intrinsic fluorescence caused by Tyr residues is quenched by a reaction substrate, coelenterazine, in concentration-dependent manner, we infer that both tyrosine residues are located in the luciferase substrate-binding cavity.Luciferase from copepod Metridia longa is a naturally secreted enzyme catalyzing the oxidative decarboxylation of coelenterazine with the emission of blue light. To date, the spatial structure of luciferase and the function of certain amino acids in bioluminescent reaction are still undetermined. From the quenching studies on intrinsic tyrosine fluorescence of the smallest isoform of M. longa luciferase and its tyrosine mutants with substitutions to Phe (Y72F and Y80F), we infer that both tyrosine residues are localized in the active site of luciferase.
      PubDate: 2017-01-05T04:42:30.953873-05:
      DOI: 10.1111/php.12694
       
  • Bioluminescence in Dinoflagellates: Evidence that the Adaptive Value of
           Bioluminescence in Dinoflagellates is Concentration Dependent
    • Authors: Karen A. Hanley; Edith A. Widder
      Pages: 519 - 530
      Abstract: Three major hypotheses have been proposed to explain why dinoflagellate bioluminescence deters copepod grazing: startle response, aposematic warning, and burglar alarm. These hypotheses propose dinoflagellate bioluminescence (A) startles predatory copepods, (B) warns potential predators of toxicity, and (C) draws the attention of higher order visual predators to the copepod's location. While the burglar alarm is the most commonly accepted hypothesis, it requires a high concentration of bioluminescent dinoflagellates to be effective, meaning the bioluminescence selective advantage at lower, more commonly observed, dinoflagellate concentrations may result from another function (e.g. startle response or aposematic warning). Therefore, a series of experiments was conducted to evaluate copepod grazing (Acartia tonsa) on bioluminescent dinoflagellates (during bioluminescent and nonbioluminescent phases, corresponding to night and day, respectively) at different concentrations (10, 1000, and 3000 cells mL−1), on toxic (Pyrodinium bahamense var. bahamense) and nontoxic (Lingulodinium polyedrum) bioluminescent dinoflagellates, and in the presence of nonluminescent diatoms (Thalassiosira eccentrica). Changes in copepod ingestion rates, clearance rates, and feeding preferences as a result of these experimental factors, particularly during the mixed trails with nonluminescent diatoms, indicate there is a concentration threshold at which the burglar alarm becomes effective and below which dinoflagellate bioluminescence functions as an aposematic warning.Three major hypotheses have been proposed to explain why dinoflagellate bioluminescence deters copepod grazing: startle response, aposematic warning, and burglar alarm. These hypotheses propose dinoflagellate bioluminescence startles predatory copepods, warns potential predators of toxicity, or draws the attention of higher order visual predators to the copepod's location, respectively. While the burglar alarm is the most commonly accepted hypothesis, it requires a high concentration of bioluminescent dinoflagellates to be effective. The series of experiments conducted for this study indicate there is a concentration threshold at which the burglar alarm becomes effective and below which dinoflagellate bioluminescence functions as an aposematic warning.
      PubDate: 2017-02-28T01:50:28.333512-05:
      DOI: 10.1111/php.12713
       
  • Bioluminescence Imaging of Spheroids for High-throughput Longitudinal
           Studies on 3D Cell Culture Models
    • Authors: Luca Cevenini; Maria M. Calabretta, Antonia Lopreside, Bruce R. Branchini, Tara L. Southworth, Elisa Michelini, Aldo Roda
      Pages: 531 - 535
      Abstract: Bioluminescent (BL) cell-based assays based on two-dimensional (2D) monolayer cell cultures represent well-established bioanalytical tools for preclinical screening of drugs. However, cells in 2D cultures do not often reflect the morphology and functionality of living organisms, thus limiting the predictive value of 2D cell-based assays. Conversely, 3D cell models have the capability to generate the extracellular matrix and restore cell-to-cell communications; thus, they are the most suitable model to mimic in vivo physiology. In this work, we developed a nondestructive real-time BL imaging assay of spheroids for longitudinal studies on 3D cell models. A high-throughput BL 3D cell-based assay in micropatterned 96-well plate format is reported. The assay performance was assessed using the transcriptional regulation of nuclear factor K beta response element in human embryonic kidney (HEK293) cells. We compared concentration–response curves for tumor necrosis factor-α with those obtained using conventional 2D cell cultures. One of the main advantages of this approach is the nonlysing nature of the assay, which allows for repetitive measurements on the same sample. The assay can be implemented in any laboratory equipped with basic cell culture facilities and paves the way to the development of new 3D bioluminescent cell-based assays.Bioluminescence imaging of 3D-Hek293 spheroids.
      PubDate: 2017-02-28T01:30:29.013234-05:
      DOI: 10.1111/php.12718
       
  • Mutants of Ca2+-regulated Photoprotein Obelin for Site-specific
           Conjugation
    • Authors: Vasilisa V. Krasitskaya; Ludmila P. Burakova, Anastasia A. Komarova, Eugenia E. Bashmakova, Ludmila A. Frank
      Pages: 553 - 557
      Abstract: Color variants of Ca2+-regulated photoprotein obelin were shown to be an important tool for dual-analyte binding assay. To provide site-directed conjugation with biospecific molecules, several obelin color mutants carrying unique cysteine residues were obtained and characterized for their novel properties. A pair of obelins Y138F,A5C and W92F,H22E,D12C was found to be most suitable (in terms of high bioluminescent activity and stability) as reporters in simultaneous assay of two targets in a sample. Availability of SH-groups, accessible for chemical modification, essentially simplifies the synthesis of biospecific conjugates, increases their yield and conserves obelins' bioluminescence activity. Conjugates with immunoglobulin and oligonucleotide were produced and successfully applied in single nucleotide polymorphism genotyping.A pair of novel obelins Y138F,A5C and W92F1,H22E,D12C was found to be most suitable as reporters in simultaneous assay of two targets in a sample. Availability of SH-groups, accessible for chemical modification, essentially simplifies the synthesis of biospecific conjugates, increases their yield and conserves obelins' bioluminescence activity.
      PubDate: 2017-03-08T04:45:27.779469-05:
      DOI: 10.1111/php.12712
       
  • The Properties and Activity of TiO2/beta-SiC Nanocomposites in Organic
           Dyes Photodegradation
    • Authors: Katarzyna Pstrowska; Bartłomiej Maciej Szyja, Hanna Czapor-Irzabek, Adam Kiersnowski, Jerzy Walendziewski
      Pages: 558 - 568
      Abstract: The TiO2/beta-SiC nanocomposites containing 0–25 wt. % of beta-SiC were synthesized by the sol-gel method and tested in the photodegradation of methylene blue and methyl orange water solutions. With the increase in SiC content, only a slight decrease in energy band gap was observed (3.19–3.12 eV), together with significant increase in the surface area of the catalysts (42.7–80.4 m2 g−1). In the synthesized material, the anatase phase of TiO2 was present in the form of small agglomerates resulting from the mechanical mixing process. In the process conditions (catalyst concentration 0.5 g L−1, initial dye concentration 100 ppm, light source 100 W UV-Vis lamp), we have observed no signs of catalyst deactivation. The significantly higher photodegradation activity of methylene blue than methyl orange can be attributed to the preferable pH of the solution compared to pHPZC and the cationic character of the first dye. In case of methyl orange, pH process conditions substantially limit the contact of the catalyst with the dye, as negatively charged surface of the catalysts repels the dissociated anionic dye molecules.TiO2/beta-SiC nanocomposites containing 0–25 wt% of beta-SiC were tested in the photodegradation of methylene blue (MB) and methyl orange (MO) 100 ppm water solutions. With the increase in SiC content, only a slight decrease in energy band gap was observed (3.19–3.12 eV), together with significant increase in the SBET of the catalysts (42.7–80.4 m2 g−1). The significantly higher photodegradation activity of MB than MO can be attributed to the preferable pH of the solution compared to pHPZC and the cationic character of the MB. In the case of MO, pH process conditions substantially limit the contact of the catalyst with the dye.
      PubDate: 2017-02-28T01:50:41.624554-05:
      DOI: 10.1111/php.12705
       
  • Cation- and Anion-Substituted Potassium Manganese Phosphate, KMnP3O9:
           Luminescence and Photocatalytic Studies
    • Authors: Sudhakar Reddy Chandiri; Ravi Gundeboina, Sreenu Kurra, Ravinder Guje, Malathi Maligi, Vithal Muga
      Pages: 569 - 578
      Abstract: Phosphates as multifunctional materials were of vital importance in the environmental and energy fields. In the present work, a new cyclophosphate, potassium manganese phosphate (KMnP3O9) (hereafter KMPO), was prepared by solid state method. Cations (Ag+ and Cu2+) and anion (N3−) were substituted into KMPO lattice via ion-exchange and solid state methods, respectively. The as-prepared materials were characterized by powder X–ray diffraction, SEM–EDS and UV–visible diffuse reflectance spectra. Rietveld refinement was carried out for parent material. All the prepared materials were found to crystallize in the hexagonal lattice and isomorphous with KCoP3O9. The nitrogen content in N3−-substituted KMPO was estimated by EDS and O-N-H analysis. The bandgap energy of the cation- and anion-substituted samples was lower compared to that of pristine KMPO. Gouy method was employed to determine the magnetic susceptibility of KMPO. The photoluminescence property of Mn2+ in all the samples was studied, and the color coordinates were calculated using CIE 1931 chromaticity. The photocatalytic activity of visible light active material, N3−-substituted KMPO, was examined against the degradation of methylene blue and methyl violet at ambient conditions.The framework structure of KMnP3O9 is built from P3O93- anions sharing corners or edges with MnO6 polyhedra. Potassium ions are located in P3O9 tunnels and surrounded by six oxygen atoms.
      PubDate: 2017-01-23T07:01:02.386634-05:
      DOI: 10.1111/php.12673
       
  • Chemiluminescence of Cigarette Smoke: Salient Features of the Phenomenon
    • Authors: Galina F. Fedorova; Valery A. Menshov, Aleksei V. Trofimov, Yury B. Tsaplev, Rostislav F. Vasil'ev, Olga I. Yablonskaya
      Pages: 579 - 589
      Abstract: The study disclosed herein provides for the first time a detailed experimental support for the general mechanism of the cigarette-smoke-derived chemiluminescence, as an example par excellence of the excited-state generation in a chemically complex aerosol medium. The mechanism involves chemiexcitation in a unimolecular transformation of the smoke-borne free radical species. However, the concentration of these radicals, [r∙], obeys a bimolecular (second-order) kinetics and depends on a particulate-phase content (total particulate matter, TPM) of the cigarette smoke. The decrease in [r∙] with increasing the TPM amount manifests radical-scavenging propensity of the smoke particulate phase. Astonishingly, no energy transfer takes place from the primary excited light-emitting species to luminophoric molecules abundant in the smoke. The reported results build up fundamentals of a facile chemiluminescence assay for free radical properties of the smoke. The experimental approaches developed for this study are of general scope and may be used for mechanistic elucidation of the excited-state generation in chemical systems and environments of an arbitrary complexity.Chemiluminescence of cigarette smoke comes about from an excited-state generation in a unimolecular transformation of the smoke-borne free radical species, while a predominant disappearance of the latter is bimolecular. The particulate phase (tar) of the smoke exhibits remarkable antiradical propensity manifested by the decrease in the α value upon increasing the smoke tar content.
      PubDate: 2017-02-06T01:55:32.70323-05:0
      DOI: 10.1111/php.12689
       
  • The Anthocyanins, Oenin and Callistephin, Protect RPE Cells Against
           Oxidative Stress
    • Authors: Sally M. Yacout; Elizabeth R. Gaillard
      Pages: 590 - 599
      Abstract: The retinal pigment epithelium (RPE) is a highly metabolic layer of postmitotic cells lining Bruch's membrane in the retina. While these cells contain endogenous photosensitizers that mediate blue light-induced damage, it has also been shown that blue light exposure damages mitochondrial DNA in RPE cells resulting in mitochondrial dysfunction and unregulated generation of reactive oxygen species (ROS). As RPE cells are postmitotic, it is imperative to decrease oxidative stress to these cells and preserve function. Dietary plant-derived antioxidants such as anthocyanins offer a simple and accessible solution for decreasing oxidative stress. The anthocyanins malvidin-3-O-glucoside (oenin) and pelargonidin-3-O-glucoside (callistephin) were tested for their ability and efficacy in decreasing ROS generation and preserving mitochondrial redox activity in blue light-irradiated ARPE-19 cells. A significant decrease in intracellular ROS with concurrent increase in mitochondrial redox activity was observed for tested concentrations of oenin, while callistephin was beneficial to stressed cells at higher concentrations. These findings suggest anthocyanins are effective antioxidants in blue light-stressed RPE cells in vitro. Additionally, oxidation products of these anthocyanins were examined using LC/MS and findings suggest the possibility of multiple oxidation sites for these compounds.The antioxidant properties of the anthocyanins oenin and callistephin were tested in photo-stressed retinal pigment epithelial (RPE) cells. Intracellular ROS production and mitochondrial redox activity was assessed in response to blue light irradiation. LC/MS was used to identify oxidation products of these anthocyanins and elucidate structural modifications. A decrease in intracellular ROS with concurrent increase in mitochondrial redox activity was observed for oenin while callistephin was beneficial to stressed cells at higher concentrations. In vitro, oenin and callistephin behave as antioxidants against blue light-mediated photo-oxidation in human RPE cells and may offer an accessible means of preventing oxidative damage to RPE cells.
      PubDate: 2017-02-06T01:55:26.597102-05:
      DOI: 10.1111/php.12683
       
  • Bimodal Targeting Using Sulfonated, Mannosylated PEI for Combined Gene
           Delivery and Photodynamic Therapy
    • Authors: Upendra Chitgupi; Yi Li, Mingfu Chen, Shuai Shao, Marie Beitelshees, Myles Joshua Tan, Sriram Neelamegham, Blaine A. Pfeifer, Charles Jones, Jonathan F. Lovell
      Pages: 600 - 608
      Abstract: Photodynamic therapy (PDT) and gene delivery have both been used to target both cancer cells and tumor-associated macrophages (TAMs). Given the complex nature of tumor tissue, there could be merit in combining these strategies simultaneously. In this study, we developed a bimodal targeting approach to both cancer cells and macrophages, employing materials conducive to both gene delivery and PDT. Polymers libraries were created that consisted of cationic polyethyleneimine (PEI) conjugated to the photosensitizer pyropheophorbide-a, with sulfonation (to target selectin-expressing cells) and mannosylation (to target TAMs). Polyplexes, consisting of these polymers electrostatically bound to DNA, were analyzed for transfection efficacy and cytotoxicity toward epithelial cells and macrophages to assess dual-targeting. This study provides preliminary proof of principle for using modified PEI for targeted gene delivery and PDT.Polyethyleneimine (PEI), an amine-rich, cationic polymer is modified with sulfonate and mannose groups. This results in targeting to cells that express selectins and mannose receptors. The polymer is also modified with pyropheophorbide-a, a photosensitizer. The modified polymer is demonstrated for use both as a targeted photosensitizer for photodynamic therapy and as a vector for gene delivery.
      PubDate: 2017-02-07T01:40:31.085429-05:
      DOI: 10.1111/php.12688
       
  • Subcellular Targeting as a Determinant of the Efficacy of Photodynamic
           Therapy
    • Authors: David Kessel
      Pages: 609 - 612
      Abstract: In prior studies, we have identified the ability of low-level lysosomal photodamage to potentiate the phototoxic effect of subsequent photodamage to mitochondria. The mechanism involves calpain-mediated cleavage of the autophagy-associated protein ATG5 to form a proapoptotic fragment (tATG5). In this report, we explore the permissible time lag between the two targeting procedures along with the effect of simultaneously targeting both lysosomes and mitochondria. This was found to be as effective as the sequential protocol with no gap between the irradiation steps. Inhibition of calpain reversed the enhanced efficacy of the “simultaneous” protocol. It appears that even a minor level of lysosomal photodamage can have a significant effect on the efficacy of subsequent mitochondrial photodamage. We propose that these results may explain the efficacy of Photofrin, a photosensitizing product that also targets both lysosomes and mitochondria for photodamage.A very low level of prior or simultaneous lysosomal photodamage (NPe6) can convert a 10% photokilling effect from mitochondrial photodamage (BPD) into an LD50 effect.
      PubDate: 2017-01-27T10:44:58.6227-05:00
      DOI: 10.1111/php.12692
       
  • In vivo Confocal Raman Spectroscopic Analysis of the Effects of Infrared
           Radiation in the Human Skin Dermis
    • Authors: Monica Bergamo Lopes; Ramu Rajasekaran, Ana Clara Figueira Lopes Cançado, Airton Abrahão Martin
      Pages: 613 - 618
      Abstract: Human skin is the outer covering of the body, and its composition changes with overexposure to environmental pollution and solar radiation. Infrared (IR) radiation is capable of penetrating more deeply into the skin producing free radicals causing irreversible damage. Confocal Raman spectroscopy was considered as a potential tool for the in vivo analysis of the different metabolic conditions with respect to different depths of the skin. In this regard, this work verifies the influence of infrared radiation on the skin dermis after having been exposed to 432 J cm−2 which corresponds to the dose received in a day in the summer time in a tropical region. This study was performed with 17 female volunteers who were divided into two groups. The marked skin area was exposed twice to IR radiation for a duration of 30 min each with an interval of 30 min. The spectral signatures were collected in the fingerprint region before (T0) and after 60 min (T60) of IR irradiation. The analysis shows that, on average, no significant variations occurred in group I and decreased collagen was observed in group II. However, when considering the effect seen in each individual, collagen degradation was detected in 60% of volunteers.Infrared (IR) radiation is capable of penetrating deeply into the skin producing free radicals and irreversible damage. In this regard, confocal Raman spectroscopy is considered for the in vivo analysis of the different metabolic conditions, and we verify the influence of IR radiation on the skin dermis after having been exposed to 432 J cm−2. On average, no significant variations were observed in group I, and decreased collagen was observed in group II. However, when considered individually, collagen degradation was detected in 60% of volunteers.
      PubDate: 2017-02-16T01:10:43.793907-05:
      DOI: 10.1111/php.12701
       
  • Changes in Time Spent Outdoors During the Daytime in Rural Populations in
           Four Geographically Distinct Regions in China: A Retrospective Study
    • Authors: Qian Gao; Fang Wang, Liwen Hu, Jiaming Yu, Rong Liu, Yang Wang, Yang Liu
      Pages: 619 - 625
      Abstract: Changes in time-activity patterns may influence personal exposure to various environmental factors and affect individual health. However, few studies have investigated the changes in patterns of time spent outdoors. To investigate the trends in outdoor activity in recent decades in China, a retrospective questionnaire was used to examine the amount and pattern of time spent outdoors during the day by 2076 subjects in four geographically distinct rural regions of China. Rural Chinese people spent less time outdoors than they used to because of the economic development, increase in education and changes in working conditions that occurred over time. Outdoor time was the shortest during the school stage of life (Sanya: 3.24–3.61; Shaoxing: 3.35–3.68; Lhasa: 4.37–4.54; Xiuyan: 2.94–3.26 h per day). Subjects in wealthy regions spent less time outdoors during their working stage of life. In the four regions in this study, the average daily times spent outdoors were 3–13% lower for subjects aged 40–59 years and 20–38% lower for those under 40 years compared to subjects aged 60 years and over. Certain health-related issues, such as vitamin D deficiency, will become more prominent in China if this trend continues.This study investigated the amount and pattern of time spent outdoors during the day by 2076 subjects in four geographically distinct rural regions in China. The average daily hours spent outdoors were 3–13% lower for subjects aged 40–59 years and 20–38% lower for those under 40 years compared to subjects aged 60 years and over. Outdoor time was the shortest during the school stage of life. The greatest decrease in time spent outdoors occurred between the young group and the old group during the work stage.
      PubDate: 2017-02-28T01:55:48.565587-05:
      DOI: 10.1111/php.12714
       
  • Computed Regioselectivity and Conjectured Biological Activity of Ene
           Reactions of Singlet Oxygen with the Natural Product Hyperforin
    • Authors: Inna Abramova; Benjamin Rudshteyn, Joel F. Liebman, Alexander Greer
      Pages: 626 - 631
      Abstract: Hyperforin is a constituent of St. John's wort and coexists with the singlet oxygen sensitizer hypericin. Density functional theory, molecular mechanics and Connolly surface calculations show that accessibility in the singlet oxygen “ene” reaction favors the hyperforin “southwest” and “southeast” prenyl (2-methyl-2-butenyl) groups over the northern prenyl groups. While the southern part of hyperforin is initially more susceptible to oxidation, up to 4 “ene” reactions of singlet oxygen can take place. Computational results assist in predicting the fate of adjacent hydroperoxides in hyperforin, where the loss of hydrogen atoms may lead to the formation of a hydrotrioxide and a carbonyl instead of a Russell reaction.This is a theoretical study of “ene” reactions of singlet oxygen with hyperforin. Shown is a brief compass to give directions of prenyl locations where the southern part of the natural product is more susceptible to singlet oxygenation.
      PubDate: 2017-02-16T01:10:38.666682-05:
      DOI: 10.1111/php.12706
       
  • Daily Variation of UV-induced Erythema and the Action of Solar Filters
    • Authors: Ana Flo; Ana C. Calpena, Antoni Díez-Noguera, Alfons Pozo, Trinitat Cambras
      Pages: 632 - 635
      Abstract: UV rays may cause several degrees of skin damage, which makes sunscreen research necessary. In addition, skin sensitivity shows daily variations, which can interfere in the detection of the efficacy of the filters. Here, we studied the UV-induced erythema in hairless rats at two times of the day (light and darkness) using a colorimeter method. The effect of an emulsion with solar filters with or without melatonin was also assayed. Results indicate that the value of a* (from CIELAB color space values L* a* b) was the most useful variable to evaluate the erythema. However, at the UV intensity used, erythema was only detected when irradiation was carried out during the activity phase of the animal, enabling the detection of the protective action of the sunscreen at this time. Thus, daily variations in skin sensitivity have been demonstrated and should be taken into account in dermatological research.UV-induced erythema in hairless rats was tested at two times of the day using a colorimeter method. Erythema was detected when irradiation occurred 4 hours after the activity onset of the animals (16 HALO), but not at 4 HALO. Variables a*, R and x were all useful to measure erythema. However, the action of the solar filters was only detected using a* and only at 16 HALO.
      PubDate: 2017-01-05T04:51:12.688923-05:
      DOI: 10.1111/php.12670
       
  • 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 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. 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 hypophysectomized 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.Possible neuroendocrine pathways involved in spleenic immunosuppressive action evoked by exposure of murine skin to ultraviolet B (UVB) radiation. UVB-induced afferent neural signals activate the central HPA axis resulting in pituitary proopiomelanocortin-derived ACTH and adrenal corticosterone release to plasma. Slower immunosuppressive action, takes 12–24 h (upper part). UVB-induced afferent neuronal signals affect CNS and directly activate adrenal gland (CORT, neurotransmitters) and spleen (neurotransmitters, neuropeptides). Rapid immunosuppression, 30–90 min (lower part).
      PubDate: 2016-11-01T05:06:02.695909-05:
      DOI: 10.1111/php.12642
       
  • Perspectives on Bioluminescence Mechanisms
    • Authors: John Lee
      Pages: 389 - 404
      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.What's in the Bioluminescence Black Box' (1) The means by which vibrational energy of the transition state transforms into a product electronic state with more than 50% efficiency. (2) The direct evidence for the firefly luciferin and coelenterazine dioxetanones. (3) The nondioxetanone excitation mechanism in bacterial bioluminescence and identification of the emitter. (4) The variation within firefly luciferases from different species that explains how the bioluminescence color is modulated among species. (5) The interaction with their cognate antenna proteins, lumazine protein and GFP (Green-Fluorescent Protein), responsible for bioluminescence color tuning in the bacterial and coelenterazine systems.
      PubDate: 2016-12-03T01:36:36.258629-05:
      DOI: 10.1111/php.12650
       
  • Firefly Luciferase-based Fusion Proteins and their Applications in
           Bioanalysis
    • Authors: Daria V. Smirnova; Natalia N. Ugarova
      Pages: 436 - 447
      Abstract: Firefly luciferase is widely used in molecular biology and bioanalytical systems as a reporter molecule due to the high quantum yield of the bioluminescence, availability of stable mutant forms of the enzyme with prescribed spectral characteristics and abundance of bacterial expression systems suitable for production of recombinant proteins in limitless quantities. In this review, we described fusion proteins of luciferase with biotin-binding domain and streptavidin, with proteins A and G, antibodies, with DNA- and RNA-binding proteins, as well as fusion proteins designed for BRET systems. The firefly luciferase-based fusion proteins are represented as an effective tool for the development of different bioanalytical systems such as (1) systems in which luciferase is attached to the surface of the target and the bioluminescence signal is detected from the specific complexes formed; (2) BRET-based systems, in which the specific interaction induces changes in the bioluminescence spectrum; and (3) systems that use modified or split luciferases, in which the luciferase activity changes under the action of the analyte. All these systems have wide application in biochemical analysis of physiologically important compounds, for the detection of pathogenic bacteria and viruses, for evaluation of protein–protein interactions, assaying of metabolites involved in cell communication and cell signaling.Firefly luciferase is widely used in molecular biology and bioanalytical systems as a reporter molecule. The firefly luciferase-based fusion proteins are represented as an effective tool for the development of different bioanalytical systems, such as (1) systems in which luciferase is attached to the surface of the target and the bioluminescence signal is detected from the specific complexes formed; (2) BRET-based systems, in which the specific interaction induces changes in the bioluminescence spectrum; (3) systems that use modified or split-luciferases, in which the luciferase activity changes under the action of the analyte.
      PubDate: 2016-11-30T04:45:31.875287-05:
      DOI: 10.1111/php.12656
       
  • Tibetan Firefly Luciferase with Low Temperature Adaptation
    • Authors: Yasuo Mitani; Ryo Futahashi, Zichao Liu, Xingcai Liang, Yoshihiro Ohmiya
      Pages: 466 - 472
      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 3300 m. 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 7.0–7.5. 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.A firefly living in the Tibetan plateau, Shangri-La, was collected and analyzed for its luciferase activity using recombinant protein. The altitude of collecting place was more than 3300 m, and the temperature was around 10°C. The luciferase activity showed high activity at low temperature suggesting its adaptation to the habitat.
      PubDate: 2016-11-03T12:26:13.784294-05:
      DOI: 10.1111/php.12643
       
  • 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
      Pages: 473 - 478
      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 Escherichia 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 Photinus 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 time-lapse photograph by Spencer Black (Blackvisual.com) entitled “Searching for Love” is a beautiful illustration of the mysterious Blue Ghost (Phausis reticulata) fireflies on a summer night in North Carolina. We recently witnessed this fascinating natural display in the Dupont State Recreational Forest while collecting several adult males. Using tiny lanterns from 18 specimens, we cloned the Blue Ghost luciferase gene and then studied the properties of the corresponding enzyme. We offer an explanation for the mesmerizing bluish-white color of the luminous streaks and report the puzzling similarity of the luciferase to that of fireflies found only in Japan.
      PubDate: 2016-11-10T02:45:37.127274-05:
      DOI: 10.1111/php.12649
       
  • Spectroscopic Properties of Amine-substituted Analogues of Firefly
           Luciferin and Oxyluciferin
    • Authors: Michio Kakiuchi; Soichiro Ito, Minoru Yamaji, Vadim R. Viviani, Shojiro Maki, Takashi Hirano
      Pages: 486 - 494
      Abstract: Spectroscopic and photophysical properties of firefly luciferin and oxyluciferin analogues with an amine substituent (NH2, NHMe and NMe2) at the C6' position were studied based on absorption and fluorescence measurements. Their π-electronic properties were investigated by DFT and TD-DFT calculations. These compounds showed fluorescence solvatochromism with good quantum yields. An increase in the electron-donating strength of the substituent led to the bathochromic shift of the fluorescence maximum. The fluorescence maxima of the luciferin analogues and the corresponding oxyluciferin analogues in a solvent were well correlated with each other. Based on the obtained data, the polarity of a luciferase active site was explained. As a result, the maximum wavelength of bioluminescence for a luciferin analogue was readily predicted by measuring the photoluminescence of the luciferin analogue in place of that of the corresponding oxyluciferin analogue.The spectroscopic and photophysical properties of firefly luciferin and oxyluciferin analogues with an amine substituent (NH2, NHMe and NMe2) at the C6' position were studied. The electron donating strength of the amine substituent has important role to modulate their π-electronic, fluorescence and bioluminescence properties.
      PubDate: 2016-12-16T06:00:33.198233-05:
      DOI: 10.1111/php.12654
       
  • Unanimous Model for Describing the Fast Bioluminescence Kinetics of
           Ca2+-regulated Photoproteins of Different Organisms
    • Authors: Elena V. Eremeeva; Sergey I. Bartsev, Willem J. H. Berkel, Eugene S. Vysotski
      Pages: 495 - 502
      Abstract: Upon binding their metal ion cofactors, Ca2+-regulated photoproteins display a rapid increase of light signal, which reaches its peak within milliseconds. In the present study, we investigate bioluminescence kinetics of the entire photoprotein family. All five recombinant hydromedusan Ca2+-regulated photoproteins—aequorin from Aequorea victoria, clytin from Clytia gregaria, mitrocomin from Mitrocoma cellularia and obelins from Obelia longissima and Obelia geniculata—demonstrate the same bioluminescent kinetics pattern. Based on these findings, for the first time we propose a unanimous kinetic model describing the bioluminescence mechanism of Ca2+-regulated photoproteins.Bioluminescence of a great number of marine organisms, mostly coelenterates, is due to the presence of Ca2+-regulated photoproteins demonstrating the same bioluminescent kinetics pattern. In the present study, we investigate bioluminescence kinetics of the entire photoprotein family using five recombinant hydromedusan Ca2+-regulated photoproteins—aequorin from Aequorea victoria, clytin from Clytia gregaria, mitrocomin from Mitrocoma cellularia and obelins from Obelia longissima and Obelia geniculata. For the first time, we propose a unanimous kinetic model describing the bioluminescence mechanism of Ca2+-regulated photoproteins.
      PubDate: 2016-12-16T06:00:28.304444-05:
      DOI: 10.1111/php.12664
       
  • Theoretical Study of Dinoflagellate Bioluminescence
    • Authors: Ming-Yu Wang; Ya-Jun Liu
      Pages: 511 - 518
      Abstract: Dinoflagellates are the most ubiquitous luminescent protists in the marine environment and have drawn much attention for their crucial roles in marine ecosystems. Dinoflagellate bioluminescence has been applied in underwater target detection. The luminescent system of dinoflagellates is a typical luciferin–luciferase one. However, the excited-state oxyluciferin is not the light emitter of dinoflagellate bioluminescence as in most luciferin–luciferase bioluminescent organisms. The oxyluciferin of bioluminescent dinoflagellates is not fluorescent, whereas its luciferin emits bright fluorescence with similar wavelength of the bioluminescence. What is the light emitter of dinoflagellate bioluminescence and what is the chemical process of the light emission like' These questions have not been answered by the limited experimental evidence so far. In this study, for the first time, the density functional calculation is employed to investigate the geometries and properties of luciferin and oxyluciferin of bioluminescent dinoflagellate. The calculated results agree with the experimental observations and indicate the luciferin or its analogue, rather than oxyluciferin, is the bioluminophore of dinoflagellate bioluminescence. A rough mechanism involving energy transfer is proposed for dinoflagellate bioluminescence.This figure shows the schematic process of dinoflagellate bioluminescence. LCF is in blue. The excited state is in dark red with star and the ground state in gold.
      PubDate: 2016-12-02T02:37:00.625437-05:
      DOI: 10.1111/php.12657
       
  • 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
      Pages: 536 - 540
      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 and the procedure steps were described.Principles for evaluation of the toxic effect (lower line) and antioxidant effect (upper line) of fullerenols which were used as a representative of bioactive compounds.
      PubDate: 2016-10-17T03:17:03.014021-05:
      DOI: 10.1111/php.12639
       
  • A Novel Streptavidin–luciferase Fusion Protein: Preparation, Properties
           and Application in Hybridization Analysis of DNA
    • Authors: Daria V. Smirnova; Maya Y. Rubtsova, Vitaly G. Grigorenko, Natalia N. Ugarova
      Pages: 541 - 547
      Abstract: A streptavidin–luciferase fusion protein comprising the thermostable mutant form of firefly luciferase Luciola mingrelica and minimal core streptavidin was constructed. The streptavidin–luciferase fusion was mainly produced in a tetrameric form with high luciferase and biotin-binding activities. It was shown that fusion has the same Km values for ATP and luciferin and the bioluminescence spectra as initial luciferase. The linear dependence of the bioluminescence signal on the content of the fusion was observed within the range of 10−18–10−13 mol per well. Successful application of obtained fusion in a biospecific bioluminescence assay based on biotin–streptavidin interactions was demonstrated by the example of a specific DNA hybridization analysis. A DNA hybridization analysis for Escherichia coli cells identification was developed using unique for these cells gadB fragment encoding glutamate decarboxylase. The amplified biotinylated GadB fragments were hybridized with the immobilized oligonucleotide probes; then, the biotin in the DNA duplexes was detected using the streptavidin–luciferase fusion protein. To reach the high sensitivity of the assay, we optimized the conditions of the assay. It was shown that the use of Pluronic for plate modification resulted in a significant reduction in the DNA detection limit which finally was 0.4 ng per well.A streptavidin–luciferase fusion protein comprising the thermostable mutant form of firefly luciferase Luciola mingrelica and minimal core streptavidin was produced in highly active tetrameric form and successfully applied in a biospecific bioluminescence assay based on biotin–streptavidin interactions. The DNA hybridization analysis for the specific identification of E. coli cells was developed using this fusion protein. The unique for these cells GadB fragment encoding glutamate decarboxylase was biotinylated during amplification, hybridized with the immobilized oligonucleotide probes; then, the biotin in the DNA duplexes was detected using the streptavidin–luciferase fusion protein.
      PubDate: 2016-12-23T07:13:53.316643-05:
      DOI: 10.1111/php.12666
       
  • 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
      Pages: 548 - 552
      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.Novel hybrid protein possessing obelin's Ca2+-triggered bioluminescence and streptavidin's affinity to biotin moiety was developed and applied as a highly-sensitive bioluminescent reporter for binding assays.
      PubDate: 2016-11-03T12:26:08.375457-05:
      DOI: 10.1111/php.12648
       
 
 
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