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https://www.readbyqxmd.com/read/28637029/blue-enriched-morning-light-as-a-countermeasure-to-light-at-the-wrong-time-effects-on-cognition-sleepiness-sleep-and-circadian-phase
#1
Mirjam Münch, Claudia Nowozin, Johannes Regente, Frederik Bes, Jan De Zeeuw, Sven Hädel, Amely Wahnschaffe, Dieter Kunz
Light during the day and darkness at night are crucial factors for proper entrainment of the human circadian system to the solar 24-h day. However, modern life and work styles have led to much more time spent indoors, often with lower daytime and higher evening/nighttime light intensity from electrical lighting than outdoors. Whether this has long-term consequences for human health is being currently investigated. We tested if bright blue-enriched morning light over several days could counteract the detrimental effects of inadequate daytime and evening lighting...
June 22, 2017: Neuropsychobiology
https://www.readbyqxmd.com/read/28636344/ruthenium-complexes-are-ph-activated-metallo-prodrugs-phamps-with-light-triggered-selective-toxicity-toward-cancer-cells
#2
Fengrui Qu, Seungjo Park, Kristina Martinez, Jessica L Gray, Fathima Shazna Thowfeik, John A Lundeen, Ashley E Kuhn, David J Charboneau, Deidra L Gerlach, Molly M Lockart, James A Law, Katherine L Jernigan, Nicole Chambers, Matthias Zeller, Nicholas A Piro, W Scott Kassel, Russell H Schmehl, Jared J Paul, Edward J Merino, Yonghyun Kim, Elizabeth T Papish
Metallo prodrugs that take advantage of the inherent acidity surrounding cancer cells have yet to be developed. We report a new class of pH-activated metallo prodrugs (pHAMPs) that are activated by light- and pH-triggered ligand dissociation. These ruthenium complexes take advantage of a key characteristic of cancer cells and hypoxic solid tumors (acidity) that can be exploited to lessen the side effects of chemotherapy. Five ruthenium complexes of the type [(N,N)2Ru(PL)](2+) were synthesized, fully characterized, and tested for cytotoxicity in cell culture (1A: N,N = 2,2'-bipyridine (bipy) and PL, the photolabile ligand, = 6,6'-dihydroxybipyridine (6,6'-dhbp); 2A: N,N = 1,10-phenanthroline (phen) and PL = 6,6'-dhbp; 3A: N,N = 2,3-dihydro-[1,4]dioxino[2,3-f][1,10]phenanthroline (dop) and PL = 6,6'-dhbp; 4A: N,N = bipy and PL = 4,4'-dimethyl-6,6'-dihydroxybipyridine (dmdhbp); 5A: N,N = 1,10-phenanthroline (phen) and PL = 4,4'-dihydroxybipyridine (4,4'-dhbp)...
June 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28636018/fluorescence-lifetime-microscopy-reveals-the-biologically-related-photophysical-heterogeneity-of-oxyblepharismin-in-light-adapted-blue-blepharisma-japonicum-cells
#3
G Checcucci, B Storti, F Ghetti, G Signore, R Bizzarri
The step-up photophobic response of the heterotrich ciliate Blepharisma japonicum is mediated by a hypericinic pigment, blepharismin, which is not present in any of the known six families of photoreceptors, namely rhodopsins, phytochromes, xanthopsins, cryptochromes, phototropins, and BLUF proteins. Upon irradiation, native cells become light-adapted (blue) by converting blepharismin into the photochemically stable oxyblepharismin (OxyBP). So far, OxyBP has been investigated mainly from a photophysical point of view in vitro, either alone or complexed with proteins...
June 21, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28635593/the-protein-slr1143-is-an-active-diguanylate-cyclase-in-synechocystis-sp-pcc-6803-and-interacts-with-the-photoreceptor-cph2
#4
Veronika Angerer, Philipp Schwenk, Thomas Wallner, Volkhard Kaever, Andreas Hiltbrunner, Annegret Wilde
Cyclic-di-GMP is an ubiquitous second messenger in bacteria. Several c-di-GMP receptor proteins have been identified to date, and downstream signalling pathways are often mediated through protein-protein interactions. The photoreceptor Cph2 from the cyanobacterium Synechocystis sp. PCC 6803 comprises three domains related to c-di-GMP metabolism: two GGDEF and one EAL domain. It has been shown that the C-terminal GGDEF domain acts as blue-light triggered c-di-GMP producer thereby inhibiting motility of the cells in blue light...
June 21, 2017: Microbiology
https://www.readbyqxmd.com/read/28635081/understanding-and-improving-photo-control-of-ion-channels-in-nociceptors-with-azobenzene-photoswitches
#5
Alexandre Mourot, Christian Herold, Michael A Kienzler, Richard H Kramer
BACKGROUND AND PURPOSE: We previously developed a photoisomerizable local anaesthetic, named QAQ, to gain rapid, optical control over pain signaling without involving genetic modification. In darkness or in green light, trans-QAQ blocks voltage-gated K(+) and Na(+) channels and silences action potentials in pain-sensing neurons. Upon photoisomerization to cis with near UV light, QAQ blockade is rapidly relieved and neuronal activity is restored. However, the molecular mechanism of cis and trans QAQ blockade is not known...
June 20, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28634231/hyperactivity-of-the-arabidopsis-cryptochrome-cry1-l407f-mutant-is-caused-by-a-structural-alteration-close-to-the-cry1-atp-binding-sit
#6
Christian Orth, Nils Niemann, Lars Hennig, Lars-Oliver Essen, Alfred Batschauer
Plant cryptochromes (cry) act as UV-A/blue light receptors. The prototype, Arabidopsis thaliana cry1, regulates several light responses during the life cycle, including de-etiolation, and is also involved in regulating flowering time. The cry1 photocycle is initiated by light absorption by its FAD chromophore, which is most likely fully oxidized (FADox) in the dark state and photoreduced to the neutral flavin semiquinone (FADH(o)) in its lit state. Cryptochromes lack the DNA-repair activity of the closely related DNA photolyases, but retain the ability to bind nucleotides such as ATP...
June 20, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28633330/the-asparagine-rich-protein-nrp-interacts-with-the-verticillium-effector-pevd1-and-regulates-the-subcellular-localization-of-cryptochrome-2
#7
Ruimin Zhou, Tong Zhu, Lei Han, Mengjie Liu, Mengyuan Xu, Yanli Liu, Dandan Han, Dewen Qiu, Qingqiu Gong, Xinqi Liu
The soil-borne fungal pathogen Verticillium dahliae infects a wide range of dicotyledonous plants including cotton, tobacco, and Arabidopsis. Among the effector proteins secreted by V. dahliae, the 16 kDa PevD1 induces a hypersensitive response in tobacco. Here we report the high-resolution structure of PevD1 with folds resembling a C2 domain-like structure with a calcium ion bound to the C-terminal acidic pocket. A yeast two-hybrid screen, designed to probe for molecular functions of PevD1, identified Arabidopsis asparagine-rich protein (NRP) as the interacting partner of PevD1...
June 13, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28633062/blue-light-induced-reactive-oxygen-species-from-flavin-mononucleotide-and-flavin-adenine-dinucleotide-on-lethality-of-hela-cells
#8
Ming-Yeh Yang, Chih-Jui Chang, Liang-Yü Chen
Photodynamic therapy (PDT) is a safe and non-invasive treatment for cancers and microbial infections. Various photosensitizers and light sources have been developed for clinical cancer therapies. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are the cofactor of enzymes and are used as photosensitizers in this study. Targeting hypoxia and light-triggering reactive oxygen species (ROS) are experimental strategies for poisoning tumor cells in vitro. HeLa cells are committed to apoptosis when treated with FMN or FAD and exposed to visible blue light (the maximum emitted wavelength of blue light is 462nm)...
June 13, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28632959/defect-based-modulation-of-opto-electronic-properties-for-bio-functionalized-hexagonal-boron-nitride-nanosheets
#9
Mehdi Shakourian-Fard, Hadiseh Heydari, Ganesh Kamath
Defect engineering could potentially allow for dramatic tuning of optoelectronic properties of two-dimensional materials. With the help of density functional theory (DFT) calculations, we present a systematic study of the DNA Nucleobases (NBs) adsorbed on hexagonal boron-nitride nanoflake (h-BNNF) and boron and nitrogen monovacancies. The presence of such VN and VB defects increases the binding strength of NBs by 9 kcal/mol and 34 kcal/mol, respectively (h-BNNF-VB> h-BNNF-VN> h-BNNF). A more negative electrostatic potential at the B vacancy-site makes h-BNNF-VB surface more reactive than h-BNNF-VN surface enabling H-bonding interactions with NBs...
June 20, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28632841/green-light-autofluorescence-versus-combined-blue-light-autofluorescence-and-near-infrared-reflectance-imaging-in-geographic-atrophy-secondary-to-age-related-macular-degeneration
#10
Maximilian Pfau, Lukas Goerdt, Steffen Schmitz-Valckenberg, Matthias M Mauschitz, Divyansh K Mishra, Frank G Holz, Moritz Lindner, Monika Fleckenstein
Purpose: To compare the intermodality and interreader agreement for geographic atrophy (GA) lesion size quantification in green-light fundus autofluorescence (GAF; excitation = 518 nm) versus combined blue-light fundus autofluorescence (BAF; excitation = 488 nm) and near-infrared reflectance (NIR; 820 nm) -based grading. Methods: Confocal scanning laser ophthalmoscopy (cSLO) GAF, BAF, and NIR images of 40 eyes from 29 patients (mean age 79.7 years) with GA secondary to AMD were recorded according to a standardized protocol...
May 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28632317/qm-mm-study-on-the-photoreactions-of-dark-and-light-adapted-states-of-a-blue-light-ytva-lov-photoreceptor
#11
Xue-Ping Chang, Yuan-Jun Gao, Wei-Hai Fang, Ganglong Cui, Walter Thiel
The dark- and light-adapted states of YtvA LOV domains exhibit distinct excited-state behavior. We have employed high-level QM(MS-CASPT2)/MM calculations to study the photochemical reactions of the dark- and light-adapted states. The photoreaction from the dark-adapted state starts with an S1→T1 intersystem crossing followed by a triplet-state hydrogen transfer from the thiol to the flavin moiety that produces a diradical intermediate, and a subsequent internal conversion that triggers a barrierless C-S bond formation in the S0 state...
June 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28631264/targeted-use-of-leds-in-improvement-of-production-efficiency-through-phytochemical-enrichment
#12
REVIEW
E Taulavuori, K Taulavuori, J K Holopainen, R Julkunen-Tiitto, C Acar, I Dincer
Based on available literature, ecology and economy of LED (light emitting diode) lights in plant foods production were assessed and compared to HPS (high pressure sodium) and CFL (compact fluorescent light) lamps. The assessment summarises that LEDs are superior compared to other lamp types. LEDs are ideal in luminous efficiency, life span and electricity usage. Mercury, carbon dioxide and heat emissions are also lowest in comparison to HPS and CFL lamps. This indicates that LEDs are indeed economic and eco-friendly lighting devices...
June 20, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28630783/highly-sensitive-colorimetric-assay-for-determining-fe-3-based-on-gold-nanoparticles-conjugated-with-glycol-chitosan
#13
Kyungmin Kim, Yun-Sik Nam, Yeonhee Lee, Kang-Bong Lee
A highly sensitive and simple colorimetric assay for the detection of Fe(3+) ions was developed using gold nanoparticles (AuNPs) conjugated with glycol chitosan (GC). The Fe(3+) ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe(3+)-O), decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe(3+) was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation...
2017: Journal of Analytical Methods in Chemistry
https://www.readbyqxmd.com/read/28630678/on-the-colour-of-wing-scales-in-butterflies-iridescence-and-preferred-orientation-of-single-gyroid-photonic-crystals
#14
Robert W Corkery, Eric C Tyrode
Lycaenid butterflies from the genera Callophrys, Cyanophrys and Thecla have evolved remarkable biophotonic gyroid nanostructures within their wing scales that have only recently been replicated by nanoscale additive manufacturing. These nanostructures selectively reflect parts of the visible spectrum to give their characteristic non-iridescent, matte-green appearance, despite a distinct blue-green-yellow iridescence predicted for individual crystals from theory. It has been hypothesized that the organism must achieve its uniform appearance by growing crystals with some restrictions on the possible distribution of orientations, yet preferential orientation observed in Callophrys rubi confirms that this distribution need not be uniform...
August 6, 2017: Interface Focus
https://www.readbyqxmd.com/read/28630378/randomised-controlled-trial-of-the-efficacy-of-a-blue-enriched-light-intervention-to-improve-alertness-and-performance-in-night-shift-workers
#15
Tracey L Sletten, Suzanne Ftouni, Christian L Nicholas, Michelle Magee, Ronald R Grunstein, Sally Ferguson, David J Kennaway, Darren O'Brien, Steven W Lockley, Shantha M W Rajaratnam
OBJECTIVES: Night workers often experience high levels of sleepiness due to misalignment of the sleep-wake cycle from the circadian pacemaker, in addition to acute and chronic sleep loss. Exposure to light, in particular short wavelength light, can improve alertness and neurobehavioural performance. This randomised controlled trial examined the efficacy of blue-enriched polychromatic light to improve alertness and neurobehavioural performance in night workers. DESIGN: Participants were 71 night shift workers (42 males; 32...
June 19, 2017: Occupational and Environmental Medicine
https://www.readbyqxmd.com/read/28630286/efficient-switching-of-mcherry-fluorescence-using-chemical-caging
#16
Bas M C Cloin, Elke De Zitter, Desiree Salas, Vincent Gielen, Gert E Folkers, Marina Mikhaylova, Maike Bergeler, Bartosz Krajnik, Jeremy Harvey, Casper C Hoogenraad, Luc Van Meervelt, Peter Dedecker, Lukas C Kapitein
Fluorophores with dynamic or controllable fluorescence emission have become essential tools for advanced imaging, such as superresolution imaging. These applications have driven the continuing development of photoactivatable or photoconvertible labels, including genetically encoded fluorescent proteins. These new probes work well but require the introduction of new labels that may interfere with the proper functioning of existing constructs and therefore require extensive functional characterization. In this work we show that the widely used red fluorescent protein mCherry can be brought to a purely chemically induced blue-fluorescent state by incubation with β-mercaptoethanol (βME)...
June 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28629848/a-novel-intrinsic-electroretinogram-response-in-isolated-mouse-retina
#17
Motoharu Takao, Yumi Fukuda, Takeshi Morita
Since the discovery of intrinsic photosensitive retinal ganglion cell (ipRGC) was reported in 2002, many features specific to this cell type have been described. However, scare information is available on the retinographic components directly reflecting ipRGC activity. In this study, we identified the electroretinogram (microERG) that reflects the photoresponses by ipRGCs in ex vivo preparations of the mouse retina, in which classical photoreceptors (cones and rods) were ablated mechanically and photochemically...
June 16, 2017: Neuroscience
https://www.readbyqxmd.com/read/28628685/a-systematic-review-of-light-emitting-diode-led-phototherapy-for-treatment-of-psoriasis-an-emerging-therapeutic-modality
#18
Derek Ho, Eugene Koo, Andrew Mamalis, Jared Jagdeo
<p>Background: Psoriasis is a chronic, inflammatory skin condition. The economic burden of psoriasis is approximately $35.2 billion in the United States per year, and treatment costs are increasing at a higher rate than general inflation. Light emitting diode (LED) phototherapy may represent a cost-effective, efficacious, safe, and portable treatment modality for psoriasis.</p> <p>Objective: The goal of our manuscript is to review the published literature and provide evidence-based recommendations on LED phototherapy for the treatment of psoriasis...
May 1, 2017: Journal of Drugs in Dermatology: JDD
https://www.readbyqxmd.com/read/28626456/bactericidal-effect-of-photodynamic-therapy-alone-or-in-combination-with-mupirocin-or-linezolid-on-staphylococcus-aureus
#19
Vanesa Pérez-Laguna, Luna Pérez-Artiaga, Verónica Lampaya-Pérez, Isabel García-Luque, Sofía Ballesta, Santi Nonell, Manuel P Paz-Cristobal, Yolanda Gilaberte, Antonio Rezusta
Antibiotic treatments frequently fail due to the development of antibiotic resistance, underscoring the need for new treatment strategies. Antimicrobial photodynamic therapy (aPDT) could constitute an alternative therapy. In bacterial suspensions of Staphylococcus aureus, which is commonly implicated in cutaneous and mucosal infections, we evaluated the in vitro efficacy of aPDT, using the photosensitizing agents rose bengal (RB) or methylene blue (MB), alone or combined with the antibiotics mupirocin (MU) or linezolid (LN)...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28625924/protoporphyrin-ix-fluorescence-as-potential-indicator-of-psoriasis-severity-and-progression
#20
Bo Wang, Yu-Ting Xu, Li Zhang, Jie Zheng, Ronald Sroka, Hong-Wei Wang, Xiu-Li Wang
BACKGROUND AND OBJECTIVES: In psoriatic lesions, fluorescence diagnosis with blue light can detect protoporphyrin IX accumulation, especially after topical 5-aminolaevulinic acid (ALA) application. However, variable fluorescence distributions, interpersonal variations and long incubation time limit its wide application in clinic. This study is aimed to identify a consistent and convenient method to facilitate diagnosis and evaluation of psoriatic lesions. METHODS: 104 psoriatic lesions from 30 patients were evaluated...
June 15, 2017: Photodiagnosis and Photodynamic Therapy
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