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Photochemistry and Photobiology

Xiao-Yi Liu, Eunson Hwang, Bom Park, Hien T T Ngo, Yong-Kun Xiao, Tae-Hoo Yi
Notoginseng is a traditional herbal medicine widely used for medicinal therapy in Asia, as it contains numerous ginsenosides with pharmacological effects. In this study, we submitted Notoginseng stem-leaf (NGL) ginsenosides to an enzyme to create reaction the monomer products of ginsenoside C-Mx and then investigated the ability of ginsenoside C-Mx to protect the skin against ultraviolet B-induced injury in normal human dermal fibroblasts (NHDFs). Ginsenoside C-Mx alleviated UVB-induced intracellular reactive oxygen species (ROS), MMP-1, and IL-6 expression while accelerating TGF-β and procollagen type I secretion...
May 20, 2018: Photochemistry and Photobiology
Edyta M Greer, Kitae Kwon
Little attention has been focused on diradical and zwitterionic photoperoxides formed from nitrosamine compounds. Here, an attempt is made to probe the electronic character of the nitrooxide intermediate formed in photochemical reactions with triplet oxygen (3 O2 ). Theoretical studies have been conducted to screen para-substituted phenyl nitrosamines. In particular, we find that electron-withdrawing substituents produce low-lying triplet nitrooxide diradicals. A clear electronic dependence in the S0 - T1 and S0 - S1 energy gaps of nitrooxides was found using Hammett plots...
May 20, 2018: Photochemistry and Photobiology
Lu Li, Eunson Hwang, Hien T T Ngo, Seul A Seo, Pei Lin, Wei Gao, Ying Liu, Tae-Hoo Yi
Black currants (Ribes nigrum L, RN) are known as a "super fruit" to possess for their many potential health benefits such as the alleviation of oxidative stress-related disorders. However, little skin photoaging-related research has been done on the use of this agent. In the present study, we investigated the protective effects of RN in UVB-irradiated human dermal fibroblasts (NHDFs). RN treatment in UVB-irradiated skin models alleviated UVB-mediated photoaging through several mechanisms: Treatment with RN downregulated MAPK-related signaling models, such as those of activation protein 1 (AP-1) and nuclear factor kappa B (NF-κB)...
May 16, 2018: Photochemistry and Photobiology
Imran Ali, Omar M L Alharbi, Zeid A Alothman, Ahmad Yacine Badjah
Titanium oxide nanoparticles were doped with copper and characterized by XRD, FT-IR, TEM and SEM. The surface morphology was spherical with 15-26 nm as particle size. The doped titanium oxide (Co/TiO2 ) nanomaterial was used for photodegradation of amido black dye in water. The maximum photodegradation of amido black obtained was 90%. The values of free energy, and enthalpy were negative, indicating spontaneous photodegradation of amido black dye. The photodegradation of amido black dye obeyed first order kinetic model...
May 16, 2018: Photochemistry and Photobiology
Natalia S Gsponer, M Claudia Rodríguez, Rodrigo E Palacios, Carlos A Chesta
In this study, the phytoplankton structure of a freshwater reservoir located in central Argentina (Embalse Río Tercero) was analyzed using Beutler's method (Photosynthesis Research 72: 39-53, 2002), aiming to provide water quality control agencies with a reliable tool for early detection of algae blooms, particularly cyanobacteria. The method estimates the concentration of chlorophyll a (Chl a) contributed by individual algal groups in a real sample by fitting its fluorescence excitation spectrum to a linear combination of norm spectra of relevant algae groups...
May 16, 2018: Photochemistry and Photobiology
Marioly Vernhes Tamayo, André Passaglia Schuch, Teiti Yagura, Luis Baly Gil, Carlos Frederico Martins Menck, Angel Sánchez-Lamar
One approach to protect the human skin against harmful effects of solar ultraviolet (UV) radiation is to use natural products as photoprotectors. In this work, the extract from specie Phyllanthus orbicularis K was evaluated as a protective agent against the photodamage by UVB, UVA artificial lamps and environmental sunlight exposure. The plasmid DNA solutions were exposed to radiations using the DNA-dosimeter system in presence of plant extract. The DNA repair enzymes, E. coli Formamidopyrimidine-DNA glycosylase (Fpg) and T4 bacteriophage endonuclease V (T4-endo V), were employed to discriminate oxidized DNA damage and cyclobutane pyrimidine dimers (CPD) respectively...
May 16, 2018: Photochemistry and Photobiology
Sally M Yacout, Kelsey L McIlwain, Shama P Mirza, Elizabeth R Gaillard
With increasing age, there is an observable loss of melanin in retinal pigment epithelial (RPE) cells. It is possible that degradation of the pigment contributes to the pathogenesis of retinal disease, as the cellular antioxidant material is depleted. Functionally, intact melanin maintains protective qualities, while oxidative degradation of melanin promotes reactive oxygen species (ROS) generation and formation of metabolic byproducts, such as melanolipofuscin. Understanding the structural and functional changes to RPE melanin with increasing age may contribute to a better understanding of disease progression and risk factors for conditions such as Age-related macular degeneration (AMD)...
May 12, 2018: Photochemistry and Photobiology
Isla Rose Mary Barnard, Patrick Tierney, Catherine Louise Campbell, Lewis McMillan, Harry Moseley, Ewan Eadie, Christian Tom Alcuin Brown, Kenneth Wood
Non-melanoma and melanoma skin cancers are attributable to DNA damage caused by ultraviolet (UV) radiation exposure. One DNA photoproduct, the Cyclobutane Pyrimidine Dimer (CPD), is believed to lead to DNA mutations caused by UV radiation. Using radiative transfer simulations, we compare the number of CPDs directly induced by UV irradiation from artificial and natural UV sources (a standard sunbed and the midday summer Mediterranean sun) for skin types I and II on the Fitzpatrick scale. We use Monte Carlo Radiative Transfer (MCRT) modelling to track the progression of UV photons through a multi-layered three dimensional (3D) grid that simulates the upper layers of the skin...
May 12, 2018: Photochemistry and Photobiology
Sandra Estébanez, Carolina Lorente, Teodoro S Kaufman, Enrique L Larghi, Andrés H Thomas, Mariana P Serrano
Pterin derivatives are heterocyclic compounds which are present in different biological systems. Neutral aqueous solutions of pterins presents acid-base and keto-enol equilibria. These compounds under UV-A radiation fluoresce, undergo photooxidation, generate reactive oxygen species, and photoinduce the oxidation of biological substrates. As photosensitizers, they may act through different mechanisms; mainly through an electron-transfer initiated process (type I mechanism), but they also produce singlet molecular oxygen (1 O2 ) upon irradiation (type II mechanism)...
May 4, 2018: Photochemistry and Photobiology
Myles Robinson, Palak Shah, Yanhong Cui, Yu-Ying He
N6 -methyladenosine (m6 A) is the most abundant internal RNA modification among numerous post-transcriptional modifications identified in eukaryotic mRNA. m6 A modification of RNA is catalyzed by the "writer" m6 A methyltransferase enzyme complex, consisting of METTL3, METTL14, WTAP, and KIAA1429. The m6 A modification is reversible, and can be removed by "eraser" m6 A demethylase enzymes, namely, FTO and ALKBH5. The biological function of m6 A modification on RNA is carried out by RNA-binding effector proteins called "readers"...
May 4, 2018: Photochemistry and Photobiology
Marcella Gabarra Almeida Leite, Patricia M B G Maia Campos
The aim of this study was to develop and evaluate the efficacy of a multifunctional hair care formulation - Hair BB Cream - containing botanical extracts of Camellia sinensis, Vitis vinifera and Euterpe orleacea, vitamins, amino acids, UV filters and silicones for hair treatment and prevention of UV damages. The in vitro antioxidant activity of the botanical extracts was evaluated using the DPPH and chemiluminescence methods. A tensile test, combability, shine and image analysis were performed to evaluate the efficacy of the formulation...
May 4, 2018: Photochemistry and Photobiology
Hangbin Miao, John Beardall, Kunshan Gao
The physiological performance of calcified and non-calcified cells of Gephyrocapsa oceanica (NIES-1318) and their short-term responses to UV radiation were compared for cultures grown under present-day (LC, 400 μatm) and high pCO2 (HC, 1000 μatm) conditions. Similar growth rates and Fv / Fm values were observed in both types of cell under LC conditions, indicating that the loss of calcification in the non-calcified cell did not lead to a competitive disadvantage under such conditions. Detrimental effects of elevated pCO2 were observed in both cell types, with the growth rate of non-calcified cells decreasing more markedly, which might reflect a negative impact of higher cytoplasmic H+ ...
April 27, 2018: Photochemistry and Photobiology
María T Lafuente, Fernando Alférez, Luis González-Candelas
Penicillium digitatum (Pers.:Fr.) Sacc. is the main fungus causing postharvest losses in citrus fruits. Previous work showed the potential of LED blue light (LBL) in controlling P. digitatum growth. Here, we have investigated whether LBL alters the ability of this fungus to infect citrus fruits. Before fruit infection, Petri plates inoculated with the same conidia concentration were held under darkness (control) or LBL (100 μmol m-2 s-1 ) for 8 d (continuous light), or were treated with the same LBL for 3 d and then shifted to darkness for 5 d (non-continuous light)...
April 27, 2018: Photochemistry and Photobiology
Brandon J Foley, Haley Stutts, Sydney L Schmitt, Jameela Lokhandwala, Aditi Nagar, Brian D Zoltowski
Blue-light signaling pathways regulated by members of the Light-Oxygen-Voltage (LOV) domain family integrate stress responses, circadian rhythms and pathogenesis in fungi. The canonical signaling mechanism involves two LOV containing proteins that maintain homology to Neurospora crassa Vivid (NcVVD) and White Collar 1 (NcWC1). These proteins engage in homo- and heterodimerization events that modulate gene transcription in response to light. Here, we clone and characterize the VVD homolog in Botrytis cinerea (BcVVD)...
April 23, 2018: Photochemistry and Photobiology
Tomasz J Merta, Nicholas E Geacintov, Vladimir Shafirovich
The mechanistic aspects of one-electron oxidation of G-quadruplexes in the basket (Na+ ions) and hybrid (K+ ions) conformations were investigated by transient absorption laser kinetic spectroscopy and HPLC detection of the 8-oxo-7,8-dihydroguanine (8-oxoG) oxidation product. The photo-induced one-electron abstraction from G-quadruplexes was initiated by sulfate radical anions (SO4 •- ) derived from the photolysis of persulfate ions by 308 nm excimer laser pulses. In neutral aqueous solutions (pH 7.0), the transient absorbance of neutral guanine radicals, G(-H)• is observed following the complete decay of SO4 •- radicals (~10 μs after the actinic laser flash)...
April 21, 2018: Photochemistry and Photobiology
Katrin A Salva, Youn H Kim, Ziba Rahbar, Gary S Wood
Aminolevulinate-based photodynamic therapy (ALA-PDT) selectively eliminates diseased tissues primarily through the induction of intrinsic apoptotic pathway. ALA-PDT is a first-line therapy for actinic keratosis, however, it is less effective for cutaneous T-cell lymphoma (CTCL). We have previously demonstrated that the resistance of CTCL to apoptosis correlates with decreased expression of death receptors such as FAS, and that methotrexate functions as an epigenetic regulator that re-establishes the susceptibility of CTCL to extrinsic pathway apoptosis...
April 20, 2018: Photochemistry and Photobiology
Kayla Marra, Ethan P LaRochelle, M Shane Chapman, P Jack Hoopes, Karina Lukovits, Edward V Maytin, Tayyaba Hasan, Brian W Pogue
Daylight-mediated photodynamic therapy (d-PDT) as a treatment for actinic keratosis (AK) is an increasingly common technique due to a significant reduction in pain, leading to better patient tolerability. While past studies have looked at different light sources and delivery methods, this study strives to provide equivalent PpIX-weighted light doses with the hypothesis that artificial light sources could be equally as effective as natural sunlight if their PpIX-weighted fluences were equalized. Normal mouse skin was used as the model to compare blue LED light, metal halide white light, and natural sunlight, with minimal incubation time between topical ALA application and the onset of light delivery...
April 16, 2018: Photochemistry and Photobiology
Sonja Schrack, Christopher Hohl, Wolfgang Schwack
For consumer safety reasons, cosmetics that are exposed to light are evaluated with respect to phototoxicity and/or photoallergy (photosensitization). For perfumes/aftershaves, however, these tests are not performed with the cosmetic product but only with single fragrance compounds, which may influence the outcome. In the presence of a sensitizer, photoinduced oxidation of unsaturated fragrances might result in the formation of unwanted products. Therefore, using real samples, we studied the photodegradation of the common fragrance octahydro tetramethyl naphthalenylethanone (OTNE) under in-vitro irradiation, during indoor-storage, and after application on skin...
April 16, 2018: Photochemistry and Photobiology
Anna Reiffers, Christian Torres Ziegenbein, Alyn Engelhardt, Ralf Kühnemuth, Peter Gilch, Constantin Czekelius
Three mono-fluorinated derivatives of the flavin core system 10-methylisoalloxazine (MIA) were synthesized. Aqueous solutions of these compounds were characterized by steady state and time resolved spectroscopy. The positions for the fluorination (6, 7, and 8) were motivated by the nodal structure of the frontier orbitals of MIA. In comparison with MIA, the fluorination results in bathochromic (6F- and 7F-MIA) and hypsochromic (8F-MIA) shifts of the adiabatic excitation energy of the lowest allowed transition...
March 31, 2018: Photochemistry and Photobiology
Kasper Grandahl, Paul Eriksen, Kristina Sophie Ibler, Jens Peter Bonde, Ole Steen Mortensen
Exposure to solar ultraviolet radiation is the main cause of skin cancer and may well present an occupational health and safety problem. In Denmark, skin cancer is a common disease in the general population, but detailed data on solar ultraviolet radiation exposure among outdoor workers is lacking. The aim of this study is to provide objective measurements of solar ultraviolet radiation exposure on working days and at leisure and compare levels of exposure between groups of mainly-outdoor, equal-parts-outdoor-and-indoor and indoor workers...
March 30, 2018: Photochemistry and Photobiology
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