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Systemic photoprotection

Chenggang Liu, Yanjie Wang, Kaiwen Pan, Qingwei Wang, Jin Liang, Yanqiang Jin, Akash Tariq
Dwarf bamboo-dominated forests are often subjected to temporary periods of drought due to rising air temperature and decreasing rainfall. Nevertheless, the relationship among CO2 assimilation, photoprotective pathways and metabolism of reactive oxygen species (ROS) remains unexplored in bamboo species. Changes in leaf gas exchange, chlorophyll fluorescence, energy partitioning, antioxidative system and compounds related to ROS metabolism in Fargesia rufa plants subjected to drought and subsequent rewatering were analyzed...
2017: Frontiers in Plant Science
Nabil Killiny, Yasser Nehela
Huanglongbing is currently the largest threat to global citrus production. We examined the effect of HLB pathogen, Candidatus Liberibacter asiaticus-infection and/or its vector, Diaphorina citri-infestation on Valencia sweet orange leaf pigments using HPLC, followed by gene expression analysis for 46 involved genes in carotenoids- and chlorophylls-biosynthesis pathways. Both CLas and D. citri alter the total citrus leaf pigments balance with a greater impact by CLas. While zeaxanthin was accumulated in CLas-infected leaves, chlorophyllide a was increased in D...
March 30, 2017: Molecular Plant-microbe Interactions: MPMI
Indermeet Kohli, Rubina Shafi, Prescilia Isedeh, James L Griffith, Mohammed S Al-Jamal, Narumol Silpa-Archa, Bradford Jackson, Mohammed Athar, Nikiforos Kollias, Craig A Elmets, Henry W Lim, Iltefat H Hamzavi
BACKGROUND: There is a rationale for adding systemic photoprotective agents to the current photoprotection regimen. OBJECTIVE: This study was designed to objectively evaluate the molecular and photobiologic effects of oral administration of Polypodium leucotomos extract (PLE). METHODS: In all, 22 subjects with Fitzpatrick skin phototype I to III were enrolled. On day 1, subjects were irradiated with visible light, ultraviolet (UV) A1, and UVB (using 308-nm excimer laser)...
March 21, 2017: Journal of the American Academy of Dermatology
Françoise Bernerd, Claire Marionnet
Identifying and understanding the biological events that occur following ultraviolet (UV) exposure are mandatory to elucidate the biological and clinical consequences of sun exposure, and to provide efficient and adequate photoprotection strategies. The main UV-induced biological features (markers related to sunburn, cancer, photoaging immunosuppression, pigmentation), characterized in human skin in vivo, could be reproduced in adapted models of reconstructed skin in vitro, attesting their high relevance in the field of photobiology...
March 3, 2017: Current Medicinal Chemistry
Meixian Wang, Yuxuan Zhang, Peiyong Guo
Florfenicol (FF) and thiamphenicol (TAP) are two typical pharmaceuticals used widely as therapeutica antibiotic agents in aquaculture. However, little is known about the potential adverse effects of these two antibiotics on non-target organisms in the aquatic ecosystem. In this study we investigated the effects of FF and TAP on photosynthesis and the antioxidant system of the cyanobacteria Microcystis flos-aquae. Over a concentration range of 0.001-1μg/L, the results showed that both FF and TAP significantly increased the chlorophyll a content of M...
February 22, 2017: Aquatic Toxicology
Yuri Dakhiya, Duaa Hussien, Eyal Fridman, Moshe Kiflawi, Rachel Green
In plants, the circadian system controls a plethora of processes, many with agronomic importance, such as photosynthesis, photoprotection, stomatal opening, and photoperiodic development, as well as molecular processes, such as gene expression. It has been suggested that modifying circadian rhythms may be a means to manipulate crops to develop improved plants for agriculture. However, there is very little information on how the clock influences the performance of crop plants. We used a noninvasive, high-throughput technique, based on prompt chlorophyll fluorescence, to measure circadian rhythms and demonstrated that the technique works in a range of plants...
March 2017: Plant Physiology
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...
January 1, 2017: Journal of Experimental Botany
Elżbieta Romanowska, Alicja Buczyńska, Wioleta Wasilewska, Tomasz Krupnik, Anna Drożak, Paweł Rogowski, Eugeniusz Parys, Maksymilian Zienkiewicz
Three species chosen as representatives of NADP-ME C4 subtype exhibit different sensitivity toward photoinhibition, and great photochemical differences were found to exist between the species. These characteristics might be due to the imbalance in the excitation energy between the photosystems present in M and BS cells, and also due to that between species caused by the penetration of light inside the leaves. Such regulation in the distribution of light intensity between M and BS cells shows that co-operation between both the metabolic systems determines effective photosynthesis and reduces the harmful effects of high light on the degradation of PSII through the production of reactive oxygen species (ROS)...
March 2017: Planta
Koichi Kobayashi, Tatsuru Masuda
Biosynthesis of chlorophyll (Chl) involves many enzymatic reactions that share several first steps for biosynthesis of other tetrapyrroles such as heme, siroheme, and phycobilins. Chl allows photosynthetic organisms to capture light energy for photosynthesis but with simultaneous threat of photooxidative damage to cells. To prevent photodamage by Chl and its highly photoreactive intermediates, photosynthetic organisms have developed multiple levels of regulatory mechanisms to coordinate tetrapyrrole biosynthesis (TPB) with the formation of photosynthetic and photoprotective systems and to fine-tune the metabolic flow with the varying needs of Chl and other tetrapyrroles under various developmental and environmental conditions...
2016: Frontiers in Plant Science
Hong-Po Dong, Yue-Lei Dong, Lei Cui, Srinivasan Balamurugan, Jian Gao, Song-Hui Lu, Tao Jiang
BACKGROUND: Diatoms are able to acclimate to frequent and large light fluctuations in the surface ocean waters. However, the molecular mechanisms underlying these acclimation responses of diaotms remain elusive. RESULTS: In this study, we investigated the mechanism of high light protection in marine diatom Thalassiosira pseudonana using comparative proteomics in combination with biochemical analyses. Cells treated under high light (800 μmol photons m(-2)s(-1)) for 10 h were subjected to proteomic analysis...
December 5, 2016: BMC Genomics
Katherina Petrou, Peter J Ralph, Daniel A Nielsen
Light underpins the health and function of coral reef ecosystems, where symbiotic partnerships with photosynthetic algae constitute the life support system of the reef. Decades of research have given us detailed knowledge of the photoprotective capacity of phototrophic organisms, yet little is known about the role of the host in providing photoprotection in symbiotic systems. Here we show that the intracellular symbionts within the large photosymbiotic foraminifera Marginopora vertebralis exhibit phototactic behaviour, and that the phototactic movement of the symbionts is accomplished by the host, through rapid actin-mediated relocation of the symbionts deeper into the cavities within the calcium carbonate test...
February 2017: ISME Journal
Nikolai N Sluchanko, Konstantin E Klementiev, Evgeny A Shirshin, Georgy V Tsoraev, Thomas Friedrich, Eugene G Maksimov
In Cyanobacteria, the Orange Carotenoid Protein (OCP) and Fluorescence Recovery Protein (FRP) are central to the photoprotective mechanism consisting in regulated quenching of phycobilisome (PBs) fluorescence. Due to a transient and flexible nature of the light-activated red quenching form, OCP(R), which is obtained from the stable dark-adapted orange form, OCP(O), by photoconversion, the detailed mechanism of photoprotection remains unclear. Here we demonstrate that our recently described W288A mutant of the Synechocystis OCP (hereinafter called OCP(W288A)) is a fully functional analogue of the OCP(R) form which is capable of constitutive PBs fluorescence quenching in vitro with no need of photoactivation...
January 2017: Biochimica et Biophysica Acta
Yik Weng Yew, Cerrene N Giordano, Graciela Spivak, Henry W Lim
Photodermatoses associated with defective DNA repair are a group of photosensitive hereditary skin disorders. In this review, we focus on diseases and syndromes with defective nucleotide excision repair that are not accompanied by an increased risk of cutaneous malignancies despite having photosensitivity. Specifically, the gene mutations and transcription defects, epidemiology, and clinical features of Cockayne syndrome, cerebro-oculo-facial-skeletal syndrome, ultraviolet-sensitive syndrome, and trichothiodystrophy will be discussed...
November 2016: Journal of the American Academy of Dermatology
Riham Gharib, Lizette Auezova, Catherine Charcosset, Hélène Greige-Gerges
A combined approach based on cyclodextrin/drug inclusion complex formation and loading into liposomes was applied to improve the effectiveness of liposome loading with essential oils. Hydroxypropyl-β-cyclodextrin/ANE (HP-β-CD/ANE) inclusion complexes were prepared and encapsulated into liposomes (ACL). ANE-double-loaded liposomes (ACL2) were obtained with the HP-β-CD/ANE complex in the aqueous phase and ANE in the organic phase. Liposomes were prepared from saturated (Phospholipon 90H) or unsaturated (Lipoid S100) phospholipids and characterized for size, polydispersity index, zeta potential, morphology, loading rate (LR) and photo- and storage stabilities...
March 1, 2017: Food Chemistry
Yazhe Wang, Cheng Wang, Yang Ding, Jing Li, Min Li, Xiao Liang, Jianping Zhou, Wei Wang
Photodynamic therapy has emerged as a promising strategy for cancer treatment. To ensure the efficient delivery of a photosensitizer to tumor for anticancer effect, a safe and tumor-specific delivery system is highly desirable. Herein, we introduce a novel biomimetic nanoparticle named rHDL/ICG (rHDL/I), by loading amphiphilic near-infrared (NIR) fluorescent dye indocyanine green (ICG) into reconstituted high density lipoproteins (rHDL). In this system, rHDL can mediate photoprotection effect and receptor-guided tumor-targeting transportation of cargos into cells...
December 1, 2016: Colloids and Surfaces. B, Biointerfaces
Marilena Di Valentin, Maria Giulia Dal Farra, Laura Galazzo, Marco Albertini, Tim Schulte, Eckhard Hofmann, Donatella Carbonera
Triplet-triplet energy transfer from chlorophylls to carotenoids is the mechanism underlying the photoprotective role played by carotenoids in many light harvesting complexes, during photosynthesis. The peridinin-chlorophyll-a protein (PCP) is a water-soluble light harvesting protein of the dinoflagellate Amphidinium carterae, employing peridinin as the main carotenoid to fulfil this function. The dipolar coupling of the triplet state of peridinin, populated under light excitation in isolated PCP, to the MTSSL nitroxide, introduced in the protein by site-directed mutagenesis followed by spin labeling, has been measured by Pulse ELectron-electron DOuble Resonance (PELDOR) spectroscopy...
December 2016: Biochimica et Biophysica Acta
Zhengwang Sun, Sang Yong Park, Eunson Hwang, Mengyang Zhang, Seul A Seo, Pei Lin, Tae-Hoo Yi
Solar ultraviolet (UV) radiation-induced reactive oxidative species is mainly responsible for the development of photoageing. Rosmarinic acid was one of the main bioactive components detected in Thymus vulgaris (TV) we extracted. In this study, UVB-induced skin damages have been shown to be ameliorated by treatment with TV in hairless mice (HR-1) skin, demonstrated by decreased matrix metalloproteinases (MMPs) and increased collagen production. However, the underlying molecular mechanism on which TV acted was unclear...
February 2017: Journal of Cellular and Molecular Medicine
Ian Pahk, Gerdenis Kodis, Graham R Fleming, Thomas A Moore, Ana L Moore, Devens Gust
Nonphotochemical quenching (NPQ) is a photoprotective regulatory mechanism employed by many photosynthetic organisms to dynamically modulate energy flow within the photosynthetic apparatus in response to fluctuating light conditions. Activated by decreases in lumen pH produced during periods of high photon flux, NPQ induces rapid thermal dissipation of excess excitation energy. As a result, the rate of charge separation (CS) decreases, thereby limiting the accumulation of potentially deleterious reactive intermediates and byproducts...
October 4, 2016: Journal of Physical Chemistry. B
Daniel L Jones, Bonnie K Baxter
Halophilic archaea experience high levels of ultraviolet (UV) light in their environments and demonstrate resistance to UV irradiation. DNA repair systems and carotenoids provide UV protection but do not account for the high resistance observed. Herein, we consider genomic signatures as an additional photoprotective strategy. The predominant forms of UV-induced DNA damage are cyclobutane pyrimidine dimers, most notoriously thymine dimers (T^Ts), which form at adjacent Ts. We tested whether the high G + C content seen in halophilic archaea serves a photoprotective function through limiting T nucleotides, and thus T^T lesions...
September 2, 2016: Life
Federico Gonzalez-Fernandez, Brandi Betts-Obregon, Andrew T Tsin, Richard J DeSa
PURPOSE: Assaying photodecomposition is challenging because light must be used to initiate the photodamage and light must be used to monitor the photodecomposition. The experimental requirements are as follows: 1) During exposure of the actinic beam, continuously monitor the spectral characteristics of the sample, 2) uniformly expose the reactants to the actinic source, 3) obtain informative spectra in the presence of light scatter, and 4) achieve sufficient sensitivity for dilute reactants...
2016: Molecular Vision
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