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Beatriz Fernández-Marín, Gilbert Neuner, Edith Kuprian, Jose Manuel Laza, J I José Ignacio García-Plazaola, Amy Verhoeven
The photoprotective mechanisms of desiccation tolerance and freezing tolerance and their relation to molecular mobility (cell vitrification) were assessed in a single model: the exceptional subalpine and resurrection plant Ramonda myconi. Dehydrated leaves showed a drop in Fv /Fm accompanied by synthesis of zeaxanthin (Z), even in the dark, which was limited by cell vitrification after complete desiccation. The recovery of Fv /Fm after a severe drying treatment (7 d at 50% RH) confirmed the tolerance of R. myconi leaves to desiccation...
January 18, 2018: Physiologia Plantarum
Mark D Farrar, Raqib Huq, Sarah Mason, Anna Nicolaou, Kayleigh A Clarke, Tristan P Dew, Gary Williamson, Rachel E B Watson, Lesley E Rhodes
No abstract text is available yet for this article.
February 2018: Journal of the American Academy of Dermatology
H Yoshida, A Nagaoka, A Komiya, M Aoki, S Nakamura, T Morikawa, R Ohtsuki, T Sayo, Y Okada, Y Takahashi
BACKGROUND: Hyaluronan (HA) metabolism in skin fibroblasts is mediated by HYBID (HYaluronan Binding protein Involved in hyaluronan Depolymerisation, KIAA1199) and HA synthases 1/2 (HAS1/2). However, photoageing-dependent changes in HA and their molecular mechanisms, and the relationship between HA metabolism and clinical symptoms in photoaged skin remain elusive. OBJECTIVES: We examined amount, size and tissue distribution of HA and expression levels of HYBID and HAS1/2 in photoaged skin, and analysed their relationships to the degree of photoageing...
January 12, 2018: British Journal of Dermatology
Viviane C K N Deuschle, Indiara Brusco, Mariana Piana, Henrique Faccin, Leandro Machado de Carvalho, Sara Marchesan Oliveira, Carine Viana
Persea americana, popularly known as avocado, has been empirically used as analgesic and anti-inflammatory including in the skin disorder treatment. Species of the genus Persea also show a photoprotective effect against UVB radiation. We investigated the antinociceptive and anti-inflammatory effects from a topical formulation containing the P. americana leaf extract in a UVB irradiation-induced burn model in mice and performed a gel-formulation stability study. The antinociceptive and anti-inflammatory effect was evaluated through mechanical allodynia, paw oedema, and inflammatory cell infiltration...
January 11, 2018: Inflammopharmacology
Dong Yan, John Beardall, Kunshan Gao
Cell size has implications for the package effect in photon absorption as well as for metabolic scaling of metabolism. In this study, we have avoided species-related differences by using isolates of the marine planktonic diatom Coscinodiscus granii with cells of different sizes and grown at different light intensities to investigate their energy allocation strategies. To make full use of incident light, several fold variations in cellular chlorophyll a content were employed across cell size. This modulation of pigment-related light absorbance was deemed effective as similar light absorbing capacities were found in all treatments...
January 10, 2018: Photosynthesis Research
V K Sharma, V Gupta, B L Jangid, M Pathak
BACKGROUND: The Fitzpatrick classification for skin phototyping is widely used, but its usefulness in dark-skinned populations has been questioned by some researchers. Recently, skin colour measurement has been proposed for phototyping skin colour objectively. AIMS: To modify the Fitzpatrick system of skin phototyping for the Indian population and to study its correlation with skin colour using narrowband diffuse reflectance spectrophotometry METHODS: Answer choices for three items (eye colour, hair colour, colour of unexposed skin) out of 10 in the original Fitzpatrick questionnaire were modified, followed by self-administration of the original and the modified Fitzpatrick questionnaire by 70 healthy Indian volunteers...
January 10, 2018: Clinical and Experimental Dermatology
M D Horbury, A L Flourat, S E Greenough, F Allais, V G Stavros
Sinapate esters are used throughout the plant kingdom, for example in photoprotection from ultraviolet radiation. Sinapate esters are naturally produced in their E-isomeric form; however, upon exposure to ultraviolet radiation, photoisomerization drives Z-isomer formation. To elucidate the photoprotection capacity of E vs. Z forms of sinapate esters, we explore the photochemistry of the model system, Z-ethyl sinapate. Following a novel Z-ethyl sinapate synthesis, we demonstrate that photoprotection is isomer independent...
January 10, 2018: Chemical Communications: Chem Comm
Dalila E Orallo, M Florencia Fangio, Martin Poblet, Mario O Carignan, Luis Bernal, José I Carreto, Sonia G Bertolotti, M Sandra Churio
The photostability and photophysical properties of the dimethyl ester of the mycosporine-like amino acid shinorine have been experimentally evaluated in aqueous solution and in the presence of direct micelles prepared with a cationic or an anionic detergent, respectively. In comparison with shinorine, the ester molecule increases the photostability, the fluorescence quantum yield and the fluorescence lifetime in water as well as in the micellar solutions. The effects are more pronounced in sodium dodecyl sulfate solutions and suggest that the electrostatic attractions with the micellar interface contribute to limit the movement of the molecules and influence the relative rate of their deactivation channels...
January 6, 2018: Photochemistry and Photobiology
Yongfeng Lou, Huayu Sun, Sining Wang, Hao Xu, Lichao Li, Hansheng Zhao, Zhimin Gao
Higher plants have an array of photoprotection mechanisms alleviating the harmful effects of light. Non-photochemical quenching (NPQ) is one of the photoprotective mechanisms, which dissipates the excess of light energy absorbed in the light-harvesting complexes (LHCs) into thermal energy. The PsbS (photosystem II subunit S), a member of the LHC family thought to be present exclusively in higher plants, is supposed to activate NPQ through interactions with antenna proteins. However, the roles of PsbS in bamboo remain unclear...
January 4, 2018: Physiologia Plantarum
Federico Perozeni, Giulio Rocco Stella, Matteo Ballottari
Microalgae are unicellular photosynthetic organisms considered as potential alternative sources for biomass, biofuels or high value products. However, limited biomass productivity is commonly experienced in their cultivating system despite their high potential. One of the reasons for this limitation is the high thermal dissipation of the light absorbed by the outer layers of the cultures exposed to high light caused by the activation of a photoprotective mechanism called non-photochemical quenching (NPQ). In the model organism for green algae Chlamydomonas reinhardtii, NPQ is triggered by pigment binding proteins called light-harvesting-complexes-stress-related (LHCSRs), which are over-accumulated in high light...
January 5, 2018: International Journal of Molecular Sciences
Christopher G Oakley, Linda Savage, Samuel Lotz, G Rudd Larson, Michael F Thomashow, David M Kramer, Douglas W Schemske
Local adaptation is common, but the traits and genes involved are often unknown. Physiological responses to cold probably contribute to local adaptation in wide-ranging species, but the genetic basis underlying natural variation in these traits has rarely been studied. Using a recombinant inbred (495 lines) mapping population from locally adapted populations of Arabidopsis thaliana from Sweden and Italy, we grew plants at low temperature and mapped quantitative trait loci (QTLs) for traits related to photosynthesis: maximal quantum efficiency (Fv/Fm), rapidly reversible photoprotection (NPQfast), and photoinhibition of PSII (NPQslow) using high-throughput, whole-plant measures of chlorophyll fluorescence...
December 28, 2017: Journal of Experimental Botany
Nikki Cecil M Magdaong, Robert E Blankenship
Light-harvesting complexes (LHCs) serve a dual role in photosynthesis, depending on the prevailing light conditions. In low light, they ensure photosynthetic efficiency by maximizing the light absorption cross-section and subsequent energy storage. Under excess light conditions, LHCs perform photoprotective quenching functions to prevent harmful chemical species such as triplet chlorophyll and singlet oxygen from forming and damaging the photosynthetic apparatus. In this minireview, various photoprotective quenching mechanisms that have been identified in different photosynthetic organisms are surveyed and summarized, and implications for improving photosynthetic productivity are briefly discussed...
January 3, 2018: Journal of Biological Chemistry
Eugen Kress, Peter Jahns
The dynamics of non-photochemical quenching (NPQ) of chlorophyll fluorescence and the dynamics of xanthophyll conversion under different actinic light conditions were studied in intact leaves of Arabidopsis thaliana. NPQ induction was investigated during up to 180 min illumination at 450, 900, and 1,800 μmol photons m-2 s-1 (μE) and NPQ relaxation after 5, 30, 90, or 180 min of pre-illumination at the same light intensities. The comparison of wild-type plants with mutants affected either in xanthophyll conversion (npq1 and npq2) or PsbS expression (npq4 and L17) or lumen acidification (pgr1) indicated that NPQ states with similar, but not identical characteristics are induced at longer time range (15-60 min) in wild-type and mutant plants...
2017: Frontiers in Plant Science
Montserrat Rojo de la Vega, Andrea Krajisnik, Donna D Zhang, Georg T Wondrak
The transcription factor NRF2 (nuclear factor-E2-related factor 2) orchestrates major cellular defense mechanisms including phase-II detoxification, inflammatory signaling, DNA repair, and antioxidant response. Recent studies strongly suggest a protective role of NRF2-mediated gene expression in the suppression of cutaneous photodamage induced by solar UV (ultraviolet) radiation. The apocarotenoid bixin, a Food and Drug Administration (FDA)-approved natural food colorant (referred to as 'annatto') originates from the seeds of the achiote tree native to tropical America, consumed by humans since ancient times...
December 18, 2017: Nutrients
Anatoly Gitelson, Alexei Solovchenko
Established reflectance-based approaches for estimation of foliar pigment contents assume close relationship between leaf absorbance and reflectance. Complex organization and high pigment content of leaves may lead to violation of the essential assumptions under Kubleka-Munk theory relating reflectance and absorbance. We compared relationships of absorbance and reciprocal reflectance vs. pigment content in leaves collected across species, developmental stages and physiological states. As a result, limitations of reflectance-based spectroscopy for pigment quantification were revealed...
November 20, 2017: Journal of Photochemistry and Photobiology. B, Biology
Mohan Sankari, Priya Rajendra Rao, Hridya Hemachandran, Phani Kumar Pullela, George Priya Doss C, Iftikhar Aslam Tayubi, Babu Subramanian, K M Gothandam, Pooja Singh, Siva Ramamoorthy
Carotenoids are isoprenoid pigments synthesized exclusively by plants and microorganisms and play critical roles in light harvesting, photoprotection, attracting pollinators and phytohormone production. In recent years, carotenoids have been used for their health benefits due to their high antioxidant activity and are extensively utilized in food, pharmaceutical, and nutraceutical industries. Regulation of carotenoid biosynthesis occurs throughout the life cycle of plants, with vibrant changes in composition based on developmental needs and responses to external environmental stimuli...
December 13, 2017: Journal of Biotechnology
Mateusz Labudda, Elżbieta Różańska, Weronika Czarnocka, Mirosław Sobczak, Jolanta Maria Dzik
Photosynthetic efficiency and redox homeostasis are important for plant physiological processes during regular development as well as defence responses. The second-stage juveniles of the Heterodera schachtii, induce syncytial feeding sites in host roots. To ascertain whether development of the syncytia alters photosynthesis and metabolism of ROS, chlorophyll a fluorescence measurements and antioxidant responses were studied in Arabidopsis thaliana shoots at the day of inoculation and at 3, 7 and 15 days post-inoculation (dpi)...
December 14, 2017: Molecular Plant Pathology
Ida M Heerfordt, Linnea R Torsnes, Peter A Philipsen, Hans Christian Wulf
BACKGROUND: To be effective, sunscreens must be applied in a sufficient quantity and reapplication is recommended. No previous study has investigated whether time spent on sunscreen application is important for the achieved photoprotection. AIM: To determine whether time spent on sunscreen application is related to the amount of sunscreen used during a first and second application. METHODS: Thirty-one volunteers wearing swimwear applied sunscreen twice in a laboratory environment...
December 13, 2017: Photodermatology, Photoimmunology & Photomedicine
Alizée Malnoë, Alex Schultink, Sanya Shahrasbi, Dominique Rumeau, Michel Havaux, Krishna K Niyogi
Light utilization is finely tuned in photosynthetic organisms to prevent cellular damage. The dissipation of excess absorbed light energy, a process termed NPQ, plays an important role in photoprotection. Little is known about the sustained or slowly reversible form(s) of NPQ and whether they are photoprotective, in part due to the lack of mutants. The Arabidopsis thaliana suppressor of quenching1 (soq1) mutant exhibits enhanced sustained NPQ, which we term qH. To identify molecular players involved in qH, we screened for suppressors of soq1 and isolated mutants affecting either chlorophyllide a oxygenase (CAO) or the chloroplastic lipocalin (CHL), now renamed plastid lipocalin (LCNP)...
December 12, 2017: Plant Cell
Gladyston Netto MPharm, Jobin Jose
BACKGROUND: Most of the sunscreen formulations mainly contain chemicals or synthetic molecules. Nowadays, researchers are mainly focussing on herbal formulations due to toxicity of the synthetic molecules. Silymarin is a natural flavonoids having excellent antioxidant properties. Solid lipid nanoparticles are novel drug carriers which improve the drug stability and tolerance effect and also enhance the permeation effect. AIMS: This study aimed at the preparation of solid lipid nanoparticles containing silymarin that will be incorporated into a sunscreen cream and determine its sun protection factor...
December 10, 2017: Journal of Cosmetic Dermatology
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