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Isabel Aparici-Espert, Guillermo Garcia-Lainez, Inmaculada Andreu, Miguel Angel Miranda, Virginie Lhiaubet-Vallet
In this work, the attention is focused on UVA-photosensitized reactions triggered by a DNA chromophore-containing lesion, namely 5-formyluracil. This is a major oxidatively generated lesion that exhibits an enhanced light absorption in the UVB-UVA region. The mechanistic study combining photochemical and photobiological techniques shows that irradiation of 5-formyluracil leads to a triplet excited state capable of sensitizing formation of cyclobutane pyrimidine dimers in DNA via a triplet-triplet energy transfer...
January 4, 2018: ACS Chemical Biology
Brian C Thomas
We investigated the potential biological impacts at Earth's surface of stratospheric O3 depletion caused by nearby supernovae known to have occurred about 2.5 and 8 million years ago at about 50 pc distance. New and previously published atmospheric chemistry modeling results were combined with radiative transfer modeling to determine changes in surface-level solar irradiance and biological responses. We find that UVB irradiance is increased by a factor of 1.1 to 2.8, with large variation in latitude, and seasonally at high-latitude regions...
December 28, 2017: Astrobiology
Xiao Pudroma, Gongsang Duoji, Mantas Grigalavicius, Duan Jie, Asta Juzeniene
Cutaneous melanoma is a deadly skin cancer, resulting from malignant transformation of melanocytes. Long-wave ultraviolet radiation (315-400 nm) is able to damage DNA, cause mutations, and induce melanoma. However, the exact mechanisms of UVA-induced cutaneous melanoma remain a matter of debate. In this review, we give a brief characterization of the most important elements in the photobiology of UVA in melanomagenesis.
2017: Journal of Environmental Pathology, Toxicology and Oncology
D Morgado-Carrasco, X Fustà-Novell, S Podlipnik, A Combalia, P Aguilera
BACKGROUND: Solar urticaria (SU) is a rare photodermatosis. Treatment is challenging and outcomes are often disappointing. Omalizumab is an anti-IgE, currently approved for treatment of chronic spontaneous urticaria. We sought to evaluate therapy with omalizumab in refractory SU and describe predictive factors for response. MATERIALS/METHODS: Patients with refractory SU under treatment with omalizumab were included in this study. Clinical outcome was evaluated using the Urticaria Activity score 7 (UAS7), Dermatology Life Quality Index (DLQI) and Pruritus Visual Analogue scale (VAS)...
November 24, 2017: Photodermatology, Photoimmunology & Photomedicine
Bo-Sen Wu, Mark G Lefsrud
Light emitting diodes have slowly gained market share as horticultural lighting systems in greenhouses due to their rapid improvement in color performances and light outputs. These advancements have increased the availability of the full spectrum of visible wavelengths and the corresponding irradiance outputs available to plants. However, light emitting diodes owners have limited information on the proper options for personal eyewear protection as the irradiance levels have increased. The objective of this study was to measure the light transmittance performance of 12 eyewear protection including welding goggles, safety goggles, polarized glasses and sunglasses across the human visible spectrum (380-740 nm) up to an irradiance level of 1500 W·m(-2) from high-irradiant light emitting diodes assemblies...
November 20, 2017: Journal of Occupational and Environmental Hygiene
Luisa Christensen, Amanda Suggs, Elma Baron
The effects of ultraviolet radiation on human skin have been studied for years, and both its harmful and therapeutic effects are well known. Exposure to UV light can lead to sunburn, immunosuppression, skin aging, and carcinogenesis, and photoprotection is strongly advocated. However, when used under controlled conditions, UV radiation can also be helpful in the diagnosis and treatment of many skin conditions.
2017: Advances in Experimental Medicine and Biology
Anzhela Galstyan, Johannes Putze, Ulrich Dobrindt
Development of antimicrobial photodynamic therapy (aPDT) is highly dependent on the development of suitable photosensitizers (PS): ideally affinity of PS towards bacterial cells should be much higher than towards mammalian cells. Cationic charge of PS may lead to selective binding of PS to bacteria mediated by electrostatic interaction; however, the photodynamic outcome is highly dependent on the lipophilicity of PS. Herein we report the aPDT effect of silicon(IV)phthalocyanine derivatives bearing four positive charges and methyl, phenyl or naphthyl substituents on the periphery of the macrocycle...
November 8, 2017: Chemistry: a European Journal
Brian L Diffey, Peter M Farr
The earliest contribution made by Jan van der Leun to the field of photobiology was studying the mechanism of UV-induced erythema in human skin - a subject he chose for his PhD in the 1960s. His contribution to this topic encouraged us to continue this work and over a number of years in the 1980s and 1990s, we carried out several studies on quantitative aspects of UV erythema. A major part of Jan's thesis focused on diffusion processes in UV erythema and his observations led him to conclude that erythema induced by radiation with wavelengths of around 300 nm was due to the actions of a diffusing mediator arising in the epidermis, whereas radiation at shorter wavelengths around 254 nm, caused erythema by exerting a direct effect on the dermal blood vessels...
October 26, 2017: Photochemical & Photobiological Sciences
Masamitsu Wada
Plant cells connected to adjacent cells with rigid cell wall cannot change their position, so that appropriate nuclear positioning according to nuclear movement is indispensable for cellular development involving unequal cell division. Sessile plants are severely affected by fluctuating environmental conditions, so that movement of organelles including nucleus is fundamental to accomplish physiological functions. The mechanisms of nuclear movement and their purposes studied recently with Arabidopsis thaliana, the model plants for genetics and molecular biology, and the nuclear behavior in fern gametophytes, an apical growing protonemal cell and a two-dimensional prothallus of Adiantum capillus-veneris, the model plants for cell biology and photobiology are described in this review...
October 17, 2017: Seminars in Cell & Developmental Biology
Dimitri D Deheyn
No abstract text is available yet for this article.
October 26, 2017: Nature
Ana Luiza Ribeiro de Souza, Ethan LaRochelle, Kayla Marra, Jason Gunn, Scott C Davis, Kimberley S Samkoe, M Shane Chapman, Edward V Maytin, Tayyaba Hasan, Brian W Pogue
BACKGROUND: Sunlight can activate photodynamic therapy (PDT), and this is a proven strategy to reduce pain caused by the conventional PDT treatment, but assessment of this and other alternative low dose rate light sources, and their efficacy, has not been studied in an objective, controlled pre-clinical setting. This study used three objective assays to assess the efficacy of different PDT treatment regimens, using PpIX fluorescence as a photophysical measure, STAT3 cross-linking as a photochemical measure, and keratinocyte damage as a photobiological measure...
October 13, 2017: Photodiagnosis and Photodynamic Therapy
Lars Kohler, Leona Nease, Pascal Vo, Jenna Garofolo, David K Heidary, Randolph P Thummel, Edith C Glazer
Light-activated compounds are powerful tools and potential agents for medical applications, as biological effects can be controlled in space and time. Ruthenium polypyridyl complexes can induce cytotoxic effects through multiple mechanisms, including acting as photosensitizers for singlet oxygen ((1)O2) production, generating other reactive oxygen species (ROS), releasing biologically active ligands, and creating reactive intermediates that form covalent bonds to biological molecules. A structure-activity relationship (SAR) study was performed on a series of Ru(II) complexes containing isomeric tetramethyl-substituted bipyridyl-type ligands...
September 26, 2017: Inorganic Chemistry
Suleyman I Allakhverdiev, Sergey K Zharmukhamedov, Margarita V Rodionova, Vladimir A Shuvalov, Charles Dismukes, Jian-Ren Shen, James Barber, Göran Samuelsson, Govindjee
Vyacheslav Vasilevich (V.V.) Klimov (or Slava, as most of us called him) was born on January 12, 1945 and passed away on May 9, 2017. He began his scientific career at the Bach Institute of Biochemistry of the USSR Academy of Sciences (Akademy Nauk (AN) SSSR), Moscow, Russia, and then, he was associated with the Institute of Photosynthesis, Pushchino, Moscow Region, for about 50 years. He worked in the field of biochemistry and biophysics of photosynthesis. He is known for his studies on the molecular organization of photosystem II (PSII)...
September 18, 2017: Photosynthesis Research
Mayumi Hatakeyama, Atsushi Fukunaga, Ken Washio, Kumiko Taguchi, Yoshiko Oda, Kanako Ogura, Chikako Nishigori
UV radiation, particularly UVB, is the major risk factor for the induction of skin cancer, and it induces skin inflammation and immunosuppression. Although reports documented that Langerhans cells (LCs) play various roles in photobiology, little is known about whether they contribute to UVB-induced cutaneous inflammation. Recently, the anti-inflammatory effect of apoptotic cells was noted. This study focuses on the roles of LCs and apoptotic cells in UVB-induced cutaneous inflammation. We show that LCs are essential for resolution of UVB-induced cutaneous inflammation...
October 15, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
Xian-Fu Zhang, Xudong Yang, Baomin Xu
Herein, four covalent BODIPY heterodimers that differ by dihedral angles were shown to be highly efficient excited triplet state (T1) photosensitizers (PSs) for singlet oxygen formation with a quantum yield (ΦΔ) of up to 0.94 as compared to their respective monomers, which had only negligible ΦΔ of ca. 0.060. More interestingly, these PSs generate T1via charge recombination mechanism rather than traditional inter-system crossing. The photosensitizing ability of dimers is easily tuned by either the dihedral angle (between the two linked BODIPYs) or solvent polarity...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
Qicai Xiao, Juan Wu, Xin Pang, Yue Jiang, Pan Wang, Albert Wingnang Leung, Liqian Gao, Sheng Jiang, Chuanshan Xu
Photodynamic therapy (PDT) has been developed as an alternative modality for the management of neoplastic and nonneoplastic diseases. It is a minimally invasive treatment that involves the interaction of a non-toxic photosensitizer (PS), light and molecular oxygen to generate reactive oxygen species (ROS), resulting in the destruction of unwanted cells and tissues. Discovery and development of new PSs with optimized properties are much crucial for achieving a desirable therapeutic efficacy. This review describes the photochemical and photobiological mechanisms of PDT, and outlines the recent progress in discovery and development of natural products and their derivatives as phototherapeutic drugs...
August 23, 2017: Current Medicinal Chemistry
Wanthanee Khetkorn, Rajesh P Rastogi, Aran Incharoensakdi, Peter Lindblad, Datta Madamwar, Ashok Pandey, Christian Larroche
Bio-hydrogen from microalgae including cyanobacteria has attracted commercial awareness due to its potential as an alternative, reliable and renewable energy source. Photosynthetic hydrogen production from microalgae can be interesting and promising options for clean energy. Advances in hydrogen-fuel-cell technology may attest an eco-friendly way of biofuel production, since, the use of H2 to generate electricity releases only water as a by-product. Progress in genetic/metabolic engineering may significantly enhance the photobiological hydrogen production from microalgae...
November 2017: Bioresource Technology
Bin Xie, Jingjing Zhang, Wei Chen, Junjie Hao, Yanhua Cheng, Run Hu, Dan Wu, Kai Wang, Xiaobing Luo
Human comfort has become one of the most important criteria in modern lighting architecture. Here, we proposed a tuning strategy to enhance the non-image forming photobiological effect on the human circadian rhythm based on quantum-dots-converted white light-emitting diodes (QDs-WLEDs). We introduced the limiting variability of the circadian action factor (CAF), defined as the ratio of circadian efficiency and luminous efficiency of radiation. The CAF was deeply discussed and was found to be a function of constraining the color rendering index (CRI) and correlated color temperatures...
October 20, 2017: Nanotechnology
Ophilia I L Mawphlang, Eros V Kharshiing
Rising temperatures during growing seasons coupled with altered precipitation rates presents a challenging task of improving crop productivity for overcoming such altered weather patterns and cater to a growing population. Light is a critical environmental factor that exerts a powerful influence on plant growth and development ranging from seed germination to flowering and fruiting. Higher plants utilize a suite of complex photoreceptor proteins to perceive surrounding red/far-red (phytochromes), blue/UV-A (cryptochromes, phototropins, ZTL/FKF1/LKP2), and UV-B light (UVR8)...
2017: Frontiers in Plant Science
Burak Barut, Ümit Demirbaş, Arzu Özel, Halit Kantekin
In this study, novel peripherally tetra 3-morpholinophenol substituted zinc(II) phthalocyanine (4) and its water soluble form quaternized zinc(II) phthalocyanine (ZnQ) were synthesized for the first time. These novel compounds were characterized by a combination of different spectroscopic techniques such as FT-IR, (1)H NMR, (13)C NMR, UV-vis and mass. The DNA binding of ZnQ was investigated using UV-vis absorption titration, competitive ethidium bromide, thermal denaturation and viscosity experiments that the ZnQ bound to CT-DNA via intercalation mode...
December 2017: International Journal of Biological Macromolecules
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