keyword
MENU ▼
Read by QxMD icon Read
search

Photoprotection

keyword
https://www.readbyqxmd.com/read/28076815/fluorescent-labeling-preserving-ocp-photoactivity-reveals-its-reorganization-during-the-photocycle
#1
Eugene G Maksimov, Nikolai N Sluchanko, Kirill S Mironov, Evgeny A Shirshin, Konstantin E Klementiev, Georgy V Tsoraev, Marcus Moldenhauer, Thomas Friedrich, Dmitry A Los, Suleyman I Allakhverdiev, Vladimir Z Paschenko, Andrei B Rubin
Orange carotenoid protein (OCP), responsible for the photoprotection of the cyanobacterial photosynthetic apparatus under excessive light conditions, undergoes significant rearrangements upon photoconversion and transits from the stable orange to the signaling red state. This is thought to involve a 12-Å translocation of the carotenoid cofactor and separation of the N- and C-terminal protein domains. Despite clear recent progress, the detailed mechanism of the OCP photoconversion and associated photoprotection remains elusive...
January 10, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28071755/variation-in-short-term-and-long-term-responses-of-photosynthesis-and-isoprenoid-mediated-photoprotection-to-soil-water-availability-in-four-douglas-fir-provenances
#2
Laura Verena Junker, Anita Kleiber, Kirstin Jansen, Henning Wildhagen, Moritz Hess, Zachary Kayler, Bernd Kammerer, Jörg-Peter Schnitzler, Jürgen Kreuzwieser, Arthur Gessler, Ingo Ensminger
For long-lived forest tree species, the understanding of intraspecific variation among populations and their response to water availability can reveal their ability to cope with and adapt to climate change. Dissipation of excess excitation energy, mediated by photoprotective isoprenoids, is an important defense mechanism against drought and high light when photosynthesis is hampered. We used 50-year-old Douglas-fir trees of four provenances at two common garden experiments to characterize provenance-specific variation in photosynthesis and photoprotective mechanisms mediated by essential and non-essential isoprenoids in response to soil water availability and solar radiation...
January 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28070301/blood-serum-retinol-levels-in-asinara-white-donkeys-reflect-albinism-induced-metabolic-adaptation-to-photoperiod-at-mediterranean-latitudes
#3
Maria Grazia Cappai, Maria Grazia Antonietta Lunesu, Francesca Accioni, Massimo Liscia, Mauro Pusceddu, Lucia Burrai, Maria Nieddu, Corrado Dimauro, Gianpiero Boatto, Walter Pinna
Previous works on albinism form of Asinara white donkeys (Equus asinus) identified the mutation leading to the peculiar phenotype spread to all specimens of the breed. Inbreeding naturally occurred under geographic isolation, on Asinara Island, in the Mediterranean Sea. Albino individuals can be more susceptible to develop health problems when exposed to natural sun radiation. Alternative metabolic pathways involved in photoprotection were explored in this trial. Nutrition-related metabolites are believed to contribute to the conservation of Asinara donkeys, in which melanin, guaranteeing photoprotection, is lacking...
January 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28069780/a-chlorophyll-fluorescence-based-method-for-the-integrated-characterization-of-the-photophysiological-response-to-light-stress
#4
João Serôdio, William Schmidt, Silja Frankenbach
This work introduces a new experimental method for the comprehensive description of the physiological responses to light of photosynthetic organisms. It allows the integration in a single experiment of the main established manipulative chlorophyll fluorescence-based protocols. It enables the integrated characterization of the photophysiology of samples regarding photoacclimation state (generating non-sequential light-response curves of effective PSII quantum yield, electron transport rate or non-photochemical quenching), photoprotection capacity (running light stress-recovery experiments, quantifying non-photochemical quenching components) and the operation of photoinactivation and photorepair processes (measuring rate constants of photoinactivation and repair for different light levels and the relative quantum yield of photoinactivation)...
January 9, 2017: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28069222/ultrasound-assisted-extraction-of-bioactive-compounds-from-palm-pressed-fiber-with-high-antioxidant-and-photoprotective-activities
#5
Valéria Dal Prá, Felipe C Lunelli, Raquel Guidetti Vendruscolo, Rafael Martins, Roger Wagner, Ayres P Lazzaretti, Denise M Guimarães Freire, Maria Alexandri, Apostolis Koutinas, Marcio A Mazutti, Marcelo Barcellos da Rosa
This work is focused on the optimization of the ultrasound-assisted extraction of antioxidant compounds with photoprotective effect from palm pressed fiber. The influence of ultrasound intensity and pulse cycle was investigated by means of a central composite rotational design. The optimized condition was ultrasound intensity of 120W.cm(-2) and pulse factor of 0.4, yielding 3.24wt%. Compounds such as fatty acids, β-sitosterol, α-tocopherol, squalene, total phenolics and carotene were identified. The extract presented antioxidant activity towards synthetic (2,2-diphenyl-1-picrylhydrazyl - DPPH, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) - ABTS) and biological radicals (Hydroxyl - OH), besides a sun protection factor of 15...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28058723/contrasting-phenotypic-plasticity-in-the-photoprotective-strategies-of-the-invasive-species-carpobrotus-edulis-and-the-coexisting-native-species-crithmum-maritimum
#6
Erola Fenollosa, Sergi Munné-Bosch, Marta Pintó-Marijuan
Photoprotective strategies vary greatly within the plant kingdom and reflect a plant's physiological status and capacity to cope with environment variations. The plasticity and intensity of these responses may determine plant success. Invasive species are reported to show increased vigor to displace native species. Describing the mechanisms that confer such vigor is essential to understanding the success of invasive species. We performed an experiment whereby two species were monitored: Carpobrotus edulis, an aggressive invasive species in the Mediterranean basin, and Crithmum maritimum, a coexisting native species in the Cap de Creus Natural Park (NE Spain)...
January 5, 2017: Physiologia Plantarum
https://www.readbyqxmd.com/read/28058690/functions-of-chromophore-containing-domain-in-the-large-linker-lcm-polypeptide-of-phycobilisome
#7
I V Elanskaya, I A Kononova, E P Lukashev, Y V Bolychevtseva, M F Yanushin, I N Stadnichuk
In the large linker ArcE polypeptide of the phycobilisome (PBS) from the cyanobacterium Synechocystis sp. PCC 6803, the chromophore-containing 26-kDa domain was deleted with consequent disturbance of the main PBS functions. Phycobilisomes in mutant cells staying in contact with photosystem I cannot transfer energy to the photosystem II. Under the bright light conditions, the interaction of PBSs with the photoprotective orange carotenoid protein in the mutant was lost and the implementation of transition states 1 and 2 of the pigment apparatus was significantly reduced...
November 2016: Doklady. Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28039793/lippia-graveolens-photochemopreventive-effect-against-uvb-radiation-induced-skin-carcinogenesis
#8
A M García-Bores, A M Espinosa-González, A Reyna-Campos, S Cruz-Toscano, J C Benítez-Flores, C T Hernández-Delgado, S Flores-Maya, M Urzúa-Meza, I Peñalosa-Castro, C L Céspedes-Acuña, J G Avila-Acevedo
Lippia graveolens HBK (Mexican oregano) is a species that is regularly used as a condiment in Mexican cuisine. In traditional medicine, it is used for the treatment of respiratory and digestive illnesses, headaches, rheumatism and inflammation-related disorders. The main chemical components reported in this species include the following: terpenoids, iridoids and flavonoids. The aim of this study was to determine the potential photochemopreventive effect of the methanolic extract of Lippia graveolens (MELG) against ultraviolet B (UVB)-induced skin cancer in SKH-1 mice...
December 18, 2016: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28038890/challenges-in-photoprotection-introduction
#9
Henry W Lim
No abstract text is available yet for this article.
December 23, 2016: Journal of the American Academy of Dermatology
https://www.readbyqxmd.com/read/28038886/current-challenges-in-photoprotection
#10
Henry W Lim, Maria-Ivonne Arellano-Mendoza, Fernando Stengel
Electromagnetic radiation in the ultraviolet, visible, and infrared ranges all produce biologic effects. Ultraviolet filters are the most well-studied photoprotective measure for the adverse effects of ultraviolet radiation. Because of the reported endocrinologic effects of oxybenzone in animal studies, its effects on coral reefs, and its photocontact allergy potential, its use has been minimized in many countries worldwide. New developments in topical antioxidants and oral and subcutaneous agents (eg, Polypodium leucotomos extract, afamelanotide, nicotinamide) with photoprotective and antiphotocarcinogenic properties could potentially provide addition modalities for protection against the effects of visible light and infrared radiation...
December 23, 2016: Journal of the American Academy of Dermatology
https://www.readbyqxmd.com/read/28038885/ultraviolet-radiation-and-the-skin-photobiology-and-sunscreen-photoprotection
#11
Antony R Young, Joël Claveau, Ana Beatris Rossi
The efficacy of sunscreens can be measured by different methods, involving in vitro, ex vivo, or in vivo techniques. There is a need for a worldwide standardization of these methods to avoid misunderstanding and confusion among sunscreen users. The clinical benefits of sunscreens have been demonstrated in randomized controlled trials that established the role of sunscreens in the prevention of actinic keratoses, squamous cell carcinomas, nevi, and melanomas. Sunscreens also prevent photoimmunosuppression and signs of photoaging...
December 23, 2016: Journal of the American Academy of Dermatology
https://www.readbyqxmd.com/read/28038884/photoprotection-in-specific-populations-children-and-people-of-color
#12
Tania Cestari, Kesha Buster
Improved education on appropriate photoprotection in children is vital. Photoprotection for these individuals should include seeking shade, the use of physical agents (clothing, hat, sunglasses), and application of sunscreens on exposed areas. Avoidance of the use of tanning beds is an important component of education for teenagers. Ultraviolet radiation exposure induces DNA damage and photoaging in all skin types, including people of color. The extent of such damage is inversely related to constitutive skin pigmentation...
December 23, 2016: Journal of the American Academy of Dermatology
https://www.readbyqxmd.com/read/28035956/changes-of-photosynthetic-behaviors-and-photoprotection-during-cell-transformation-and-astaxanthin-accumulation-in-haematococcus-pluvialis-grown-outdoors-in-tubular-photobioreactors
#13
Litao Zhang, Fang Su, Chunhui Zhang, Fengying Gong, Jianguo Liu
The cell transformation from green motile cells to non-motile cells and astaxanthin accumulation can be induced in the green alga Haematococcus pluvialis cultured outdoors. In the initial 3 d of incubation (cell transformation phase), light absorption and photosynthetic electron transport became more efficient. After five days of incubation (astaxanthin accumulation phase), the light absorption per active reaction center (ABS/RC) increased, but the efficiency of electron transport (ψo) and the quantum yield of electron transport (φEo) decreased with increased time, indicating that the capacity of photosynthetic energy utilization decreased significantly during astaxanthin accumulation, leading to an imbalance between photosynthetic light absorption and energy utilization...
December 26, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28018387/role-of-ions-in-the-regulation-of-light-harvesting
#14
REVIEW
Radek Kaňa, Govindjee
Regulation of photosynthetic light harvesting in the thylakoids is one of the major key factors affecting the efficiency of photosynthesis. Thylakoid membrane is negatively charged and influences both the structure and the function of the primarily photosynthetic reactions through its electrical double layer (EDL). Further, there is a heterogeneous organization of soluble ions (K(+), Mg(2+), Cl(-)) attached to the thylakoid membrane that, together with fixed charges (negatively charged amino acids, lipids), provides an electrical field...
2016: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28013173/specific-roles-of-cyclic-electron-flow-around-photosystem-i-in-photosynthetic-regulation-in-immature-and-mature-leaves
#15
Wei Huang, Ying-Jie Yang, Shi-Bao Zhang
Cyclic electron flow (CEF) around photosystem I (PSI) is essential for photosynthesis in mature leaves. However, the physiological roles of CEF in immature leaves are little known. Here, we measured the PSI and PSII activities, light response changes in PSI and PSII energy quenching for immature and mature leaves of Erythrophleum guineense grown under full sunlight. Comparing with the maximum quantum yield of PSII (Fv/Fm), the immature leaves had much lower values of the maximum photo-oxidizable P700 (Pm) than the mature leaves, suggesting the unsynchronized development of PSI and PSII activities...
December 10, 2016: Journal of Plant Physiology
https://www.readbyqxmd.com/read/28011874/activation-of-nrf2-reduces-uva-mediated-mmp-1-upregulation-via-mapk-ap-1-signaling-cascades-the-photoprotective-effects-of-sulforaphane-and-hispidulin
#16
Anyamanee Chaiprasongsuk, Jinaphat Lohakul, Kitipong Soontrapa, Somponnat Sampattavanich, Pravit Akarasereenont, Uraiwan Panich
Ultraviolet A (UVA) irradiation plays a role in premature aging of the skin through triggering oxidative stress-associated stimulation of matrix metalloproteinase-1 (MMP-1) responsible for collagen degradation, a hallmark of photoaged skin. Compounds which can activate Nrf2, a transcription factor regulating antioxidant gene expression, should therefore serve as effective anti-photoaging agents. We investigated whether genetic silencing of Nrf2 could relieve UVA-mediated MMP-1 upregulation via activation of MAPK/AP-1 signaling using human keratinocyte cell line (HaCaT)...
December 23, 2016: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/28007953/the-function-of-lhcbm4-6-8-antenna-proteins-in-chlamydomonas-reinhardtii
#17
Laura Girolomoni, Paola Ferrante, Silvia Berteotti, Giovanni Giuliano, Roberto Bassi, Matteo Ballottari
In eukaryotic autotrophs, photosystems are composed of a core moiety, hosting charge separation and electron transport reactions, and an antenna system, enhancing light harvesting and photoprotection. In Chlamydomonas reinhardtii, the major antenna of PSII is a heterogeneous trimeric complex made up of LHCBM1-LHCBM9 subunits. Despite high similarity, specific functions have been reported for several members including LHCBM1, 2, 7, and 9. In this work, we analyzed the function of LHCBM4 and LHCBM6 gene products in vitro by synthesizing recombinant apoproteins from individual sequences and refolding them with pigments...
December 21, 2016: Journal of Experimental Botany
https://www.readbyqxmd.com/read/28002950/energetics-of-radical-formation-in-eumelanin-building-blocks-implications-for-understanding-photoprotection-mechanisms-in-eumelanin
#18
Filipe Agapito, Benedito J Costa Cabral
The supramolecular structure of melanin pigments is characterized by a high concentration of radical species. Therefore, the energetics of the radical formation in melanin building blocks is key for understanding the structure and the electronic properties of the pigments at the molecular level. Nevertheless, the radical energetics of even the simplest melanin building blocks are largely unknown. In order to address this fundamental issue, the bond dissociation enthalpies (BDEs) for the melanin monomers 5,6-dihydroxy-1H-indole-2-carboxylic acid (DHICA), 1H-indole-5,6-diol (DHI), and 1H-indole-5,6-dione (IQ) were determined through high-accuracy ab initio quantum chemistry methods...
December 22, 2016: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/27997134/native-mass-spectrometry-analysis-of-oligomerization-states-of-fluorescence-recovery-protein-and-orange-carotenoid-protein-two-proteins-involved-in-the-cyanobacterial-photoprotection-cycle
#19
Yue Lu, Haijun Liu, Rafael G Saer, Hao Zhang, Christine M Meyer, Veronica L Li, Liuqing Shi, Jeremy D King, Michael L Gross, Robert E Blankenship
The orange carotenoid protein (OCP) and fluorescence recovery protein (FRP) are present in many cyanobacteria and regulate an essential photoprotection cycle in an antagonistic manner as a function of light intensity. We characterized the oligomerization states of OCP and FRP by using native mass spectrometry, a technique that has the capability of studying native proteins under a wide range of protein concentrations and molecular masses. We found that dimeric FRP is the predominant state at protein concentrations ranging from 3 to 180 μM and that higher-order oligomers gradually form at protein concentrations above this range...
December 20, 2016: Biochemistry
https://www.readbyqxmd.com/read/27994060/twisting-a-%C3%AE-carotene-an-adaptive-trick-from-nature-for-dissipating-energy-during-photoprotection
#20
Manuel J Llansola-Portoles, Roman Sobotka, Elizabeth Kish, Mahendra Kumar Shukla, Andrew A Pascal, Tomáš Polívka, Bruno Robert
Cyanobacteria possess a family of one-helix high-light-inducible proteins (Hlips) that are homologous to light-harvesting antenna of plants and algae. An Hlip protein, high light inducible protein D (HliD) purified as a small complex with the Ycf39 protein is evaluated using resonance Raman spectroscopy. We show that the HliD binds two different β-carotenes, each present in two non-equivalent binding pockets with different conformations, having their (0,0) absorption maxima at 489 and 522 nm respectively. Both populations of β-carotene molecules were in all-trans configuration and the absorption position of the farthest blue-shifted β-carotene was attributed entirely to the polarizability of the environment in its binding pocked...
December 19, 2016: Journal of Biological Chemistry
keyword
keyword
13408
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"