Bibliographies thématiques / Non photochemical quencing

Littérature scientifique sur le sujet « Non photochemical quencing »

Auteur : Grafiati
Publié le 11 mars 2023

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Articles de revues sur le sujet "Non photochemical quencing"

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Schreiber, Ulrich, et Christian Neubauer. « The Polyphasic Rise of Chlorophyll Fluorescence upon Onset of Strong Continuous Illumination : II. Partial Control by the Photosystem II Donor Side and Possible Ways of Interpretation ». Zeitschrift für Naturforschung C 42, no 11-12 (1 décembre 1987) : 1255–64. http://dx.doi.org/10.1515/znc-1987-11-1218.

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The fluorescence rise kinetics in saturating light display two well separated components with largely different properties. The rapid rise from F0 to a first intermediate level, I1 is photochemically controlled, while the following phases leading to a secondary intermediate level, I2 and to a peak level, P, are limited by thermal reactions. Treatments which primarily affect components at the photosystem II donor side are shown to increase quenching at I1 and/or to suppress the secondary fluorescence rise to I2. Preillumination by single turnover saturating flashes causes I1- quenching oscillating with period-4 in dependence of flash number. It is suggested that this quenching correlates with (S2 + S3) states of the watersplitting enzyme system. Suppression of the secondary, I1 - I2 rise component is invariably found with treatments which lower electron donation rate by the watersplitting system and are known to favor the low potential form of cyt b 559. Three different mechanisms are discussed on the basis of which donor-side dependent quench­ing could be interpreted: 1) Non-photochemical quenching by accumulation of the P 680+ radical cation. 2) Dissipative photochemical quenching at a special population of PS II centers (β- or non- B centers) displaying low donor capacity and high rates of charge recombination. 3) Dissipative photochemical quenching via cyclic electron flow around PS II, involving alternate donors to P 680+ (like cyt b 559 or carotenoid in their low potential forms), which can compete when donation rate from the water splitting system is slowed down. The possibility of donor-side limitation also being involved in “energy dependent” quenching is discussed.
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Bilger, W., et U. Schreiber. « Modulation of Millisecond Chlorophyll Luminescence by Non-Photochemical Fluorescence Quenching ». Zeitschrift für Naturforschung C 44, no 11-12 (1 décembre 1989) : 966–70. http://dx.doi.org/10.1515/znc-1989-11-1215.

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Abstract By combining a high frequency modulation system for measurement of fluorescence with a phosphoroscope type apparatus for measurement of luminescence, recordings of fluorescence and luminescence induction kinetics under identical conditions were obtained. Both measuring sys­tems tolerated the application of saturating pulses of white light for rapid, transient elimination of photochemical quenching at photosystem II reaction centers, thus allowing determination of the non-photochemical quenching component. The saturation pulse induction curves of luminescence are well correlated with the corresponding curves of fluorescence, suggesting that luminescence yield is lowered by the same type of non-photochemical quenching (mostly “energy dependent quenching”) as fluorescence. Hence, in order to evaluate luminescence signals in terms of the rate of charge recombination at photosystem II reaction centers, knowledge of fluorescence quenching is required.
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Correa-Galvis, Viviana, Petra Redekop, Katharine Guan, Annika Griess, Thuy B. Truong, Setsuko Wakao, Krishna K. Niyogi et Peter Jahns. « Photosystem II Subunit PsbS Is Involved in the Induction of LHCSR Protein-dependent Energy Dissipation in Chlamydomonas reinhardtii ». Journal of Biological Chemistry 291, no 33 (29 juin 2016) : 17478–87. http://dx.doi.org/10.1074/jbc.m116.737312.

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Non-photochemical quenching of excess excitation energy is an important photoprotective mechanism in photosynthetic organisms. In Arabidopsis thaliana, a high quenching capacity is constitutively present and depends on the PsbS protein. In the green alga Chlamydomonas reinhardtii, non-photochemical quenching becomes activated upon high light acclimation and requires the accumulation of light harvesting complex stress-related (LHCSR) proteins. Expression of the PsbS protein in C. reinhardtii has not been reported yet. Here, we show that PsbS is a light-induced protein in C. reinhardtii, whose accumulation under high light is further controlled by CO2 availability. PsbS accumulated after several hours of high light illumination at low CO2. At high CO2, however, PsbS was only transiently expressed under high light and was degraded after 1 h of high light exposure. PsbS accumulation correlated with an enhanced non-photochemical quenching capacity in high light-acclimated cells grown at low CO2. However, PsbS could not compensate for the function of LHCSR in an LHCSR-deficient mutant. Knockdown of PsbS accumulation led to reduction of both non-photochemical quenching capacity and LHCSR3 accumulation. Our data suggest that PsbS is essential for the activation of non-photochemical quenching in C. reinhardtii, possibly by promoting conformational changes required for activation of LHCSR3-dependent quenching in the antenna of photosystem II.
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Hashim, Mohd Akmal, Sharir Aizat Kamaruddin, Mun Fei Yam, Ahmad Suhail Khazali, Khairunnisa Ahmad Kamil, Nor Atikah Husna Ahmad Nasir et Murray T. Brown. « Effects of Diuron, Terbuthylazine and Isoproturon on Photochemical and Non-Photochemical Quenching of Ectocarpus siliculosus ». IOP Conference Series : Earth and Environmental Science 1019, no 1 (1 avril 2022) : 012015. http://dx.doi.org/10.1088/1755-1315/1019/1/012015.

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Abstract The influence of anthropogenic discharges on the environment is an increasing concern among environmental toxicologists. This investigation set out to analyse the impacts of selected herbicides; diuron, terbuthylazine and isoproturon on two strains of Ectocarpus siliculosus with different pollution histories, LIA4 and Es524. Evaluation of their effects on photochemical quenching (qP) and non-photochemical quenching (qN) indicators have demonstrated negative impacts of all herbicides on both strains. From the results, diuron shows to exert significant negative effect at concentration as low as 5 µg L−1 followed by terbuthylazine at 10 µg L−1 (qP) and 5 µg L−1 (qN), and isoproturon at 100 µg L−1 (qP) and 50 µg L−1 (qN). Non-photochemical quenching (qN) indicator was found to exhibit greater sensitivity to the herbicides compared to photochemical quenching (qP). In both strains of E. siliculosus, the three herbicides were ranked in order of toxicity: diuron > terbuthylazine > isoproturon. This investigation provides new information on ecotoxicology of herbicides towards brown algae.
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Kitao, Mitsutoshi, Hiroyuki Tobita, Satoshi Kitaoka, Hisanori Harayama, Kenichi Yazaki, Masabumi Komatsu, Evgenios Agathokleous et Takayoshi Koike. « Light Energy Partitioning under Various Environmental Stresses Combined with Elevated CO2 in Three Deciduous Broadleaf Tree Species in Japan ». Climate 7, no 6 (3 juin 2019) : 79. http://dx.doi.org/10.3390/cli7060079.

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Understanding plant response to excessive light energy not consumed by photosynthesis under various environmental stresses, would be important for maintaining biosphere sustainability. Based on previous studies regarding nitrogen (N) limitation, drought in Japanese white birch (Betula platyphylla var. japonica), and elevated O3 in Japanese oak (Quercus mongolica var. crispula) and Konara oak (Q. serrata) under future-coming elevated CO2 concentrations, we newly analyze the fate of absorbed light energy by a leaf, partitioning into photochemical processes, including photosynthesis, photorespiration and regulated and non-regulated, non-photochemical quenchings. No significant increases in the rate of non-regulated non-photochemical quenching (JNO) were observed in plants grown under N limitation, drought and elevated O3 in ambient or elevated CO2. This suggests that the risk of photodamage caused by excessive light energy was not increased by environmental stresses reducing photosynthesis, irrespective of CO2 concentrations. The rate of regulated non-photochemical quenching (JNPQ), which contributes to regulating photoprotective thermal dissipation, could well compensate decreases in the photosynthetic electron transport rate through photosystem II (JPSII) under various environmental stresses, since JNPQ+JPSII was constant across the treatment combinations. It is noteworthy that even decreases in JNO were observed under N limitation and elevated O3, irrespective of CO2 conditions, which may denote a preconditioning-mode adaptive response for protection against further stress. Such an adaptive response may not fully compensate for the negative effects of lethal stress, but may be critical for coping with non-lethal stress and regulating homeostasis. Regarding the three deciduous broadleaf tree species, elevated CO2 appears not to influence the plant responses to environmental stresses from the viewpoint of susceptibility to photodamage.
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Neubauer, Christian, et Ulrich Schreiber. « Photochemical and Non-Photochemical Quenching of Chlorophyll Fluorescence Induced by Hydrogen Peroxide ». Zeitschrift für Naturforschung C 44, no 3-4 (1 avril 1989) : 262–70. http://dx.doi.org/10.1515/znc-1989-3-415.

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Abstract Chlorophyll Fluorescence. Fluorescence Quenching, Hydrogen Peroxide. Active Oxygen. Ascorbate Peroxidase Chlorophyll fluorescence quenching induced by H 20 2 in intact spinach chloroplasts was investi­gated with a modulation fluorometer which allows to distinguish between photochemical and non­ photochemical quenching components by the so-called saturation pulse method. Residual catalase activity was removed by washing and percoll gradient centrifugation. H2O2 was found to induce pronounced photochem ical and non-photochemical quenching, characteristic for the action of a Hill reagent, with a half-maximal rate already observed at 5 × 10-6 m . The saturation characteris­tics and maximal rate of H2O2-reduction were very similar to those of methylviologen reduction. H2O2-dependent quenching was stimulated by ascorbate and inhibited by cyanide and azide in agreement with previous findings by other researchers that H2O2-reduction involves the ascorbate peroxidase scavenging system and that the actual “Hill acceptor” is an oxidation product of ascorbate, i.e. monodehydroascorbate or dehydroascorbate. With well-coupled intact chloro­plasts reducing CO2 at 150 (μmol (mg Chl)-1h-1, iodoacetamide stopped CO2-dependent O2-evolution and consequent addition of 10″3 m H2O2 produced an O2-Solution rate of 240 (μmol (mg Chl)-1h-1 .It is concluded that light-dependent H 20 2 reduction is a very efficient reaction in intact chloroplasts. As H2O2 formation and consequent reduction also occur in vivo, the corre­sponding quenching should be considered when assimilatory electron flow is estimated from quenching coefficients. It is suggested that proton flux associated with H2O2-formation and reduc­tion may be important for the adjustment of appropriate ATP /NADPH ratios required for CO2-fixation in vivo. Furthermore, H2O2-reduction may serve as a valve reaction whenever Calvin cycle activity is limited by factors different from NADPH supply, thus protecting against photo-inhibitory damage.
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Laisk, A., et V. Oja. « Alteration of photosystem II properties with non-photochemical excitation quenching ». Philosophical Transactions of the Royal Society of London. Series B : Biological Sciences 355, no 1402 (29 octobre 2000) : 1405–18. http://dx.doi.org/10.1098/rstb.2000.0702.

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Oxygen yield from single turnover flashes and multiple turnover pulses was measured in sunflower leaves differently pre–illuminated to induce either ‘energy–dependent type’ non–photochemical excitation quenching ( q E ) or reversible, inhibitory type non–photochemical quenching ( q I ). A zirconium O 2 analyser, combined with a flexible gas system, was used for these measurements. Oxygen yield from saturating single turnover flashes was the equivalent of 1.3–2.0 μmol e − m −2 in leaves pre–adapted to low light. It did not decrease when q E quenching was induced by a 1 min exposure to saturating light, but it decreased when pre–illumination was extended to 30–60 min. Oxygen evolution from saturating multiple turnover pulses behaved similarly: it did not decrease with the rapidly induced q E but decreased considerably when exposure to saturating light was extended or O 2 concentration was decreased to 0.4%. Parallel recording of chlorophyll fluorescence and O 2 evolution during multiple turnover pulses, interpreted with the help of a mathematical model of photosystem II (PS II) electron transport, revealed PS II donor and acceptor side resistances. These experiments showed that PS II properties depend on the type of non–photochemical quenching present. The rapidly induced and rapidly reversible q E type (photoprotective) quenching does not induce changes in the number of active PS II or in the PS II maximum turnover rate, thus confirming the antenna mechanism of q E. The more slowly induced but still reversible q I type quenching (photoinactivation) induced a decrease in the number of active PS II and in the maximum PS II turnover rate. Modelling showed that, mainly, the acceptor side resistance of PS II increased in parallel with the reversible q I. Oxygen yield from single turnover flashes and multiple turnover pulses was measured in sunflower leaves differently pre–illuminated to induce either ‘energy–dependent type’ non–photochemical excitation quenching ( q E ) or reversible, inhibitory type non–photochemical quenching ( q I ). A zirconium O 2 analyser, combined with a flexible gas system, was used for these measurements. Oxygen yield from saturating single turnover flashes was the equivalent of 1.3–2.0 μmol e − m −2 in leaves pre–adapted to low light. It did not decrease when q E quenching was induced by a 1 min exposure to saturating light, but it decreased when pre–illumination was extended to 30–60 min. Oxygen evolution from saturating multiple turnover pulses behaved similarly: it did not decrease with the rapidly induced q E but decreased considerably when exposure to saturating light was extended or O 2 concentration was decreased to 0.4%. Parallel recording of chlorophyll fluorescence and O 2 evolution during multiple turnover pulses, interpreted with the help of a mathematical model of photosystem II (PS II) electron transport, revealed PS II donor and acceptor side resistances. These experiments showed that PS II properties depend on the type of non–photochemical quenching present. The rapidly induced and rapidly reversible q E type (photoprotective) quenching does not induce changes in the number of active PS II or in the PS II maximum turnover rate, thus confirming the antenna mechanism of q E. The more slowly induced but still reversible q I type quenching (photoinactivation) induced a decrease in the number of active PS II and in the maximum PS II turnover rate. Modelling showed that, mainly, the acceptor side resistance of PS II increased in parallel with the reversible q I.
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Gruber, J. Michael, Pengqi Xu, Jevgenij Chmeliov, Tjaart P. J. Krüger, Maxime T. A. Alexandre, Leonas Valkunas, Roberta Croce et Rienk van Grondelle. « Dynamic quenching in single photosystem II supercomplexes ». Physical Chemistry Chemical Physics 18, no 37 (2016) : 25852–60. http://dx.doi.org/10.1039/c6cp05493e.

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Nosalewicz, Artur, Karolina Okoń et Maria Skorupka. « Non-Photochemical Quenching under Drought and Fluctuating Light ». International Journal of Molecular Sciences 23, no 9 (6 mai 2022) : 5182. http://dx.doi.org/10.3390/ijms23095182.

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Plants grow in a variable environment in regard to soil water and light driving photochemical reactions. Light energy exceeding plant capability to use it for photochemical reactions must be dissipated by processes of non-photochemical quenching (NPQ). The aim of the study was to evaluate the impact of various components of NPQ on the response of Arabidopsis thaliana to fluctuating light and water availability. A laboratory experiment with Arabidopsis thaliana wild type (WT) and mutants npq1 and npq4 grown under optimum or reduced water availability was conducted. Dark-adapted plants were illuminated with fluctuating light (FL) of two intensities (55 and 530 μmol m−2 s−1) with each of the phases lasting for 20 s. The impact of water availability on the role of zeaxanthin and PsbS protein in NPQ induced at FL was analysed. The water deficit affected the dynamics of NPQ induced by FL. The lack of zeaxanthin or PsbS reduced plant capability to cope with FL. The synergy of both of these components was enhanced in regard to the amplitude of NPQ in the drought conditions. PsbS was shown as a component of primary importance in suiting plant response to FL under optimum and reduced water availability.
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Karapetyan, N. V. « Non-photochemical quenching of fluorescence in cyanobacteria ». Biochemistry (Moscow) 72, no 10 (octobre 2007) : 1127–35. http://dx.doi.org/10.1134/s0006297907100100.

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Thèses sur le sujet "Non photochemical quencing"

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Yokoyama, Ryo. « Functional Link Between Photoprotection Mechanisms and Thylakoid Structures in Plants ». 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225440.

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Johansson, Jänkänpää Hanna. « Stress responses of Arabidopsis plants with a varying level of non-photochemical quenching ». Doctoral thesis, Umeå universitet, Institutionen för fysiologisk botanik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-48566.

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When light energy input exceeds the capacity for photosynthesis the plant need to dissipate the excess energy and this is done through non-photo-chemical quenching (NPQ). Photochemical quenching (photosynthesis), NPQ and fluorescence are three alternative faiths of excited chlorophylls. PsbS associates to photosystem II and is involved in NPQ. The results presented in this thesis were generated on Arabidopsis plants and mainly based on wildtype Col-0 together with a mutant deficient in PsbS (npq4) and a transgene overexpressing PsbS (oePsbS). We connect light and herbivore stress and show that the level of PsbS influences the food preference of both a specialist (Plutella) and a generalist (Spodoptera) herbivore as well as oviposition of Plutella. Level of PsbS also affects both metabolomics and transcriptomics of the plant; up-regulation of genes in the jasmonic acid (JA) -pathway and amount of JA has been found in the npq4 plants after herbivory. Since many experiments were performed in field we have also characterized the field plant and how it differs from the commonly used lab plant. We have also studied the natural variation of NPQ in Arabidopsis plants both in the field and the lab. The results show surprisingly no correlation.
Överskottsenergi kan vara skadligt för en växts membran och fotosynteskomplex. Vid överskott av solenergi blir fotosystemen mättade och växten behöver därför ett sätt för att göra sig av med all överskottsenergi, detta kallas för ”icke-fotokemisk quenching” (NPQ). Fotokemisk quenching (fotosyntes), NPQ och fluoresens är tre alternativa vägar för exalterade klorofyller. PsbS är involverad i NPQ och associerar med fotosystem II. De resultat som presenteras i denna avhandling kommer från studier av modellväxten Arabidopsis thaliana (Backtrav), i huvudsak gjorda på vildtypen i jämförelse med en mutant som saknar PsbS (npq4) och en transgen som överuttrycker PsbS (oePsbS). Vi har försökt att undersöka kopplingen mellan ljus- och herbivoristress och visar här att mängden PsbS påverkar både en specialist (Plutella) och en generalist (Spodoptera) insekt vid val av föda, samt Plutella även vid äggläggning. Växternas nivå av PsbS visade sig även påverka metabolomet och transkriptomet, och vi fann en uppreglering av gener i biosyntesen för jasmonat samt mer av själva hormonet jasmonat i npq4 växter efter herbivori. Eftersom vi har gjort många av experimenten ute i fält har vi även karakteriserat en typisk Arabidopsis växt i fält samt hur denna skiljer sig från den vanligt använda lab-växten. Dessutom har vi även undersökt naturlig variation av NPQ av Arabidopsis både i fält och på lab och resultaten visar, till vår förvåning, att det inte går att finna någon korrelation mellan dessa.
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Marshall, H. L. « Photoinhibition of primary production in marine phytoplankton : modelling photon damage and non-photochemical quenching ». Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638011.

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Photoinhibition in three species of prymnesiophyte algae (Isochrysis galbana, Phaeocystis globosa and Emiliania huxleyi) was investigated using inhibitors to isolate various components. Results suggested that the three species show the same general responses, but timing and magnitude varied. I.galbana was the least susceptible to high light stress and showed a faster and greater non-photochemical quenching response than the other two species. This may be due to genetic adaptation, however characterisation of many more species is required before it becomes clear how photoinhibition responses vary in situ. A mathematical model was developed that simulates photon damage of photosystem II and subsequent effects on the initial slope of the photosynthesis/irradiance curve. Species specific differences in photoinhibition are proposed to be due to differences in pigment content and photoprotection. This was supported by the results presented, in that for each of the three species, the decline in the ratio of variable:maximum fluorescence normalised to Chlorophyll a for a given number of photons, is the same for a give species regardless of exposure irradiance. An additional model was constructed to simulate 3-step xanthophyll cycling (violaxanthin, antheraxanthin & zeaxanthin) in higher plants and chlorophyte algae. Both models were incorporated within existing photoacclimation models. The resultant model can simulate dynamic photoacclimation and photoinhibition under both nutrient replete and limiting conditions, and compares well with independent published experimental results. Experimental investigations into the 2-step xanthophyll cycle seen in prymnesiophyte algae (diadinoxanthin & diatoxanthin) presented here suggested that the relationship between non-photochemical quenching and the epoxidation state of the cycle was not as simple as the relationship seen in higher plants. Further research is required to clarify the relationship between non-photochemical quenching and this 2-step cycle, and the part of non-photochemical quenching that occurs in the presence of inhibitors of the de-epoxidation step of this cycle (DpH dependant quenching).
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Taddei, Lucilla. « The role of the LHCX light-harvesting complex protein family in diatom photoprotection ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066219/document.

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Les diatomées constituent le principal groupe du phytoplancton dans les océans, contribuant à près de 20% de la production primaire globale. Dans leur environnement très variable, les diatomées sont particulièrement efficaces dans leur capacité à ajuster leur activité photosynthétique en dissipant sous forme de chaleur l’énergie lumineuse absorbée en excès, par un processus appelé le « Non-Photochemical Quenching of chlorophyll fluorescence », (NPQ). Chez la diatomée modèle, Phaeodactylum tricornutum, il a été montré que LHCX1, une protéine proche des antennes photosynthétiques, est impliquée dans le NPQ. Par des approches intrégrées de génétique, biologie moléculaire, biochimie, imagerie des cinétiques de fluorescence et spectroscopie ultrarapide, j’ai étudié le rôle de la famille des LHCX chez P. tricornutum. J’ai tout d’abord pu corréler une expression différentielle des 4 gènes LHCX de P. tricornutum avec différentes dynamiques de NPQ et activités photosynthétiques, dans différentes conditions de lumiére et nutriments. En localisant les LHCX dans les differents complexes photosynthétiques et les différents sites de dissipation d’énergie, j’ai pu proposer un modèle de régulation dynamique du NPQ impliquant à court terme principalement LHCX1 au niveau des centres réactionnels, et une autre isoforme, possiblement LHCX3, au niveau des antennes lors d’un stress lumineux prolongé. Enfin, par le criblage d’une série de mutants potentiellement dérégulés dans leur contenu en LHCXs, j’ai pu identifier des lignées avec un NPQ altéré qui pourront constituer des nouveaux outils de recherche. Dans l’ensemble ce travail de thèse a permis de mettre en évidence la diversification fonctionnelle et l’importance de la famille des LHCX dans la fine modulation des capacités de collecte de lumière et de photoprotection, expliquant sans doute en partie le succès des diatomées dans leur environnement très fluctuant
Diatoms dominate phytoplanktonic communities in contemporary oceans, contributing to 20% of global primary productivity. In their extremely variable environment, diatoms are especially efficient in adjusting their photosynthetic activity by dissipating as heat the light energy absorbed in excess, through a process called “Non-Photochemical Quenching of chlorophyll fluorescence”, (NPQ). In the model diatom Phaeodactylum tricornutum, it has been shown that LHCX1, a photosynthetic antenna-related gene, is involved in the NPQ process. Through integrated approaches of genetics, molecular biology, biochemistry, study of the kinetics of chlorophyll fluorescence yields and ultrafast spectroscopy, I studied the role of the LHCX family in the photoprotection activity of P. tricornutum. I first correlated a differential regulation of the 4 P. tricornutum LHCX genes with different dynamics of NPQ and photosynthetic activity, in different light and nutrient conditions. By localizing the LHCXs in fractioned photosynthetic complexes and the different sites of energy dissipation, I was able to propose a model of dynamic regulation of NPQ capacity involving mainly the LHCX1 in the reaction centers, during short-term high light responses. During prolonged high light stress, the quenching occurs mainly in the antennas, potentially mediated by the LHCX3 isoform. Finally, using photosynthetic parameters, I screened a series of transgenic lines putatively deregulated in their LHCX amount, and I identified lines with altered NPQ, which could represent novel investigation tools. Altogether, this work highlighted the functional diversification and the importance of the LHCX protein family in the fine-tuning of light harvesting and photoprotection capacity, possibly contributing to explain diatoms success in their highly fluctuating environment
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Cendrero, Mateo Maria del Pilar. « Chlorophyll Fluorescence Response to Water and Nitrogen Deficit ». Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/312504.

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The increasing food demand as well as the need to predict the impact of warming climate on vegetation makes it critical to find the best tools to assess crop production and carbon dioxide (CO₂) exchange between the land and atmosphere. Photosynthesis is a good indicator of crop production and CO₂ exchange. Chlorophyll fluorescence (ChF) is directly related to photosynthesis. ChF can be measured at leaf-scale using active techniques and at field-scales using passive techniques. The measurement principles of both techniques are different. In this study, three overarching questions about ChF were addressed: Q1) How water, nutrient and ambient light conditions determine the relationships between photosynthesis and ChF? Which is the optimum irradiance level for detecting water and nutrient deficit conditions with ChF?; Q2) which are the limits within which active and passive techniques are comparable?; and Q3) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? To address these questions, two main experiments were conducted: Exp1) Concurrent photosynthesis and ChF light-response curves were measured in camelina and wheat plants growing under (i) intermediate-light and (ii) high-light conditions respectively. Plant stress was induced by (i) withdrawing water, and (ii) applying different nitrogen levels; and Exp2) coincident active and passive ChF measurements were made in a wheat field under different nitrogen treatments. The results indicated ChF has a direct relationship with photosynthesis when water or nitrogen drives the relationship. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Also, the results showed that for leaf-average-values, active measurements can be used to better understand the daily and seasonal behavior of passive ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a simple linear function. Our study showed that at times in the season when nitrogen was sufficient and photosynthesis was highest, ChF decreased because these two processes compete for available energy. These results demonstrated that ChF is a reliable indicator of crop stress and has great potential for better understand the CO₂ exchange between the land and atmosphere.
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Paul, Suman [Verfasser], Alfred R. [Akademischer Betreuer] Holzwarth et Claus A. M. [Akademischer Betreuer] Seidel. « Non-photochemical quenching mechanisms in plants - light induced reorganization of the thylakoid membrane / Suman Paul. Gutachter : Alfred R. Holzwarth ; Claus A. M. Seidel ». Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2014. http://d-nb.info/1052993710/34.

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Hernández-Prieto, Miguel Angel. « The Small Cab-like Proteins in the cyanobacterium Synechocystis sp. PCC 6803 ». Doctoral thesis, Umeå universitet, Kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-25886.

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The Small Cab-like Proteins (SCPs) in the cyanobacterium Synechocystis sp. PCC 6803 accumulate in cells grown under different stress conditions. Genes coding for SCPs have been found in all sequenced organisms performing oxygenic photosynthesis and even in the genomes of cyanophages. Deletion of multiple scp genes in Synechocystis resulted in mutants with severely impaired growth and altered pigment content. These findings indicate the importance of SCPs in photosynthesis; however, their specific function is not well understood. SCPs share a chlorophyll-binding motif with the plant light harvesting complex, suggesting that they bind chlorophyll. Here I describe my findings, which unambiguously show that SCPs are able to bind chlorophyll in vitro. Although they affect both the stoichiometric ratio of Photosystem I to II and chlorophyll stability, they do not seem to be directly involved in non-photochemical quenching. I was able to reveal the location of the SCPs within the cyanobacterial cell: in stressed cells they attach to Photosystem II in the thylakoid membrane. Furthermore, I revealed the presence of another light-harvesting like (Lil)/SCP protein in Synechocystis sp. PCC 6803. The gene, slr1544, codifying for this newly characterised LilA protein, co-transcribes together with scpD and also appears to bind to Photosystem II during stress.
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Giossi, Chiara. « Photoacclimation and photoprotection strategies in siphonous green algae of the order Bryopsidales (Codium tomentosum and Bryopsis plumosa) ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/19835/.

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Several species of Bryopsidales (Chlorophyta) are known for displaying functional absence of the xanthophyll cycle, a common photoprotection mechanism responsible for qE component of NPQ. To cope with the extreme variability of their natural environment, these algae must be able to avoid photodamage. Previous works reported significant accumulation of all-trans-neoxanthin and violaxanthin under high light acclimation in different Bryopsidales, and speculated that these xanthophylls might control the amount of energy that reaches the photosystems, causing photoprotection. In this work, we investigated photoacclimation and photoprotection strategies in two species of Bryopsidales (Codium tomentosum and Bryopsis plumosa). We first characterised the acclimation state of algae exposed for 7 days to low light or high light (respectively 20 and 1000 μmol photons m2 s−1) in terms of pigment content (HPLC) and chlorophyll a variable fluorescence (PAM). We confirmed that high light triggers significant alteration of pigment content with accumulation of trans-Neoxanthin and Violaxanthin, and for the first time we characterised thoroughly how the pigment pool is altered during acclimation. We also confirmed that no evidence of any xanthophyll cycle is present in high light acclimated cultures. On a second note we tried to answer another major question: are trans-neoxanthin and violaxanthin photoprotective? Using a novel chlorophyll a variable fluorescence approach (pNPQ assessment) and performing quantification of PSII repair capacity (via lincomycin treatment) we were not able to give a clear answer to this question. Nonetheless, we concluded that despite trans-Neoxanthin and Violaxanthin might contribute to photoprotection, this process in Bryopsidales algae is likely given by the coordination between different mechanisms that deserve to be further investigated, including chloroplast movement, PSII repair/modulation, state transitions, and PSI cyclic electron transport.
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Rousso, Benny Z. « Optimization of cyanobacteria bloom management through improved forecasting models and optical sensors ». Thesis, Griffith University, 2022. http://hdl.handle.net/10072/412995.

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Cyanobacteria are a diverse group of microorganisms adapted to a range of environmental conditions that favour their ubiquity in waterbodies. Cyanobacteria harmful blooms (CyanoHABs) are events in which a cyanobacteria population grows rapidly, dominates the phytoplankton community and may release toxins or other noxious compounds in the waterbody. The frequency and magnitude of CyanoHABs are increasing as a result of climate change and increased pollution from urbanisation and agriculture expansion, representing a major risk to the public health and economy. Management of CyanoHABs is complicated by the temporal and spatial dynamic nature of these events, and by the large diversity of cyanobacteria species. Identification of the dominant cyanobacteria species is required to select appropriate mitigation and treatment alternatives. Therefore, water authorities have longed for reliable tools to support proactive and species-targeted CyanoHAB management. Emerging monitoring technologies and data-driven models represent a tangible opportunity to optimise CyanoHABs management by integrating rapid and taxa precise features into a single tool. Optical sensors, namely in-situ fluorescence sensors, allow rapid, remote estimation of the total phytoplankton and cyanobacteria concentration in a waterbody. This is done by measuring the fluorescence of the pigments chlorophyll a, common to all phytoplankton, and phycocyanin, exclusive to cyanobacteria. However, fluorescence estimates have limited taxa precision because they cannot discriminate between cyanobacteria species, and may have reduced accuracy, due to optical interferences. Data-driven models are increasingly being used to understand and predict complex ecological patterns, including cyanobacteria species succession, but the combination of high-frequency fluorescence data with data-driven models to optimise CyanoHAB management has seldom been investigated. The aim of this doctoral thesis is to develop an integrated model able to optimise CyanoHAB management by incorporating site-specific drivers of cyanobacteria succession and factors that affect fluorescence sensor estimates. This aim was achieved by addressing four objectives: (1) to systematically review the state-of-knowledge of forecasting and predictive CyanoHAB models and their application to freshwater lakes; (2) to test and quantify interferences, if any, on fluorescence probe measurements according to diel light variability and species composition; (3) to identify and quantify, through observational data analysis, dominance of cyanobacteria species according to site-specific environmental conditions; and (4) to establish a framework for implementation of integrated models considering fluorescence sensor calibration and prediction of cyanobacteria species succession. This research project’s combination of observational data analysis and analytical laboratory work underpins its novelty and relevance. Observational data analysis was performed for three Australian drinking-water reservoirs and correlations between environmental drivers and dominance of key cyanobacteria species were determined for Wivenhoe Lake (Queensland), Tingalpa Reservoir (Queensland) and Myponga Reservoir (South Australia). Two sets of controlled laboratory experiments were then performed. The first experiment analysed the fluorescence characteristics of four key cyanobacteria species (Aphanocapsa sp., Microcystis aeruginosa, Dolichospermum circinale and Raphidiopsis raciborskii) that are often dominant in the assessed drinking-water reservoirs. The experiment quantified the variability of the species’ fluorescence characteristics throughout their respective growth phases and also compared the differences among morphologically similar species. The second experiment analysed light-induced quenching in a cyanobacterium (Dolichospermum variabilis) and a green alga (Ankistrodesmus gracilis) by simulating diel light variability under controlled temperature and stratification conditions. Lastly, a framework combining the methodological procedures from the observational data analysis and the fluorescence calibration experiments was established with the aim of supporting the development of species-targeted models utilizing fluorescence sensors. An integrated model based on the framework was developed and tested in Myponga Reservoir, South Australia. Moreover, a continuous improvement process for CyanoHAB models and guidelines of best practices for fluorescence sensors deployment, calibration and operation were developed as a result of this research. The methods and findings are provided in four peer-reviewed journal papers included as chapters in this thesis (i.e., chapters 3, 5, 6 and 7) and a final discussion chapter (chapter 8). Objective 1 findings revealed that high-frequency data, such as the data from optical sensors, can improve performance of CyanoHAB models. For Objective 2, two key findings should be highlighted. First, fluorescence per cell was found to significantly vary among species, while fluorescence per unit of biomass (estimated from biovolume) was much more consistent among species. Second, diel light variability reduced fluorescence for both cyanobacteria and green algae up to 79% under the assessed conditions. Objective 3 findings indicated that environmental drivers for cyanobacteria succession and dominance are mostly site-specific. Species-specific traits, such as diazotrophy and gas vesicles, interact in complex ways with local environmental conditions leading to variable dominance succession among species. Finally, the key findings of Objective 4 showed that the required steps to develop a species-targeted CyanoHAB model using fluorescence sensors are feasible, given that constraints in data availability are met. Overall, the findings of this PhD research indicate that CyanoHAB management can be optimised through the combination of fluorescence sensors and forecasting models based on data-driven approaches, as long as rigorous calibration and data analysis procedures are undertaken. Importantly, the findings also highlight that even though generalisable patterns of species-specific drivers exist, site-specific analysis is required due to the complex interactions between the several factors involved in the occurrence of CyanoHABs.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Wilson, Flore Adjélé. « Étude du mécanisme de photoprotection lié à l’Orange Carotenoid Protein et ses homologues chez les cyanobactéries ». Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS503/document.

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La lumière est essentielle pour les organismes photosynthétiques qui convertissent l'énergie solaire en énergie chimique. Cependant, la lumière devient dangereuse lorsque l'énergie qui arrive aux centres réactionnels de l'appareil photosynthétique, est en excès par rapport à l’énergie consommée. Dans ce cas, la chaîne de transport d'électrons photosynthétiques se réduit et les espèces réactives de l'oxygène (ROS) sont accumulées, notamment au niveau des deux photosystèmes, PSI et PSII. Les cyanobactéries ont développé des mécanismes photoprotecteurs qui diminuent l'énergie transférée au PSII atténuant ainsi l'accumulation de ROS et les dommages cellulaires, comme l’extinction non-photochimique (NPQcya) induite par la lumière bleue-verte. La soluble Orange Caroténoïde Protéine (OCPo) est essentielle pour ce mécanisme de photoprotection. L'OCP agit comme un senseur de l’intensité lumineuse et un inducteur de la dissipation d'énergie des phycobilisomes (PBS), l'antenne extra-membranaire des cyanobactéries. L'OCP est la première protéine photo-active à caroténoïde connue comme senseur. Une forte lumière bleue-verte déclenche des changements structurels dans l'OCPo qui induisent une forme active, rouge (OCPr). Le domaine N-terminal de l’OCPr, en s’intercalant entre les trimères externes d’un des cylindres basaux du cœur du PBS, augmente la dissipation thermique de l'énergie au niveau de l'antenne. L'OCP possède aussi une autre fonction : l’extinction de l’oxygène singulet, qui protège les cellules du stress oxydatif. Pour récupérer pleinement la capacité de l’antenne en faible lumière, une deuxième protéine est nécessaire, la "Fluorescence Recovery Protein" (FRP), dont le rôle est de détacher l’OCPr des PBS et d’accélérer sa reconversion en OCPo inactive. Ce manuscrit est un état des lieux des connaissances et des dernières avancées sur le mécanisme de NPQ associé à l'OCP dans les cyanobactéries
Photosynthetic organisms use light energy from the sun in order to perform photosynthesis and to convert solar energy into chemical energy. Absorbance of excess light energy beyond what can be consumed in photosynthesis is dangerous for these organisms. Reactive oxygen species (ROS) are formed at the reaction centers and collecting light antennas inducing photooxidative damage which can lead to cell death. In cyanobacteria, one of these photoprotective mechanisms consists to reduce the amount of energy arriving to the reaction centers by thermal dissipation of the excess absorbed energy. Energy dissipation is accompanied by a decrease of Photosystem II-related fluorescence emission called non-photochemical quenching (NPQ). The soluble Orange Carotenoid Protein (OCPo) is essential for this photoprotective mechanism. The OCP is the first photo-active protein with a carotenoid known as light intensity sensor and acts as energy quencher of the phycobilisome (PB), the extra-membrane antenna of cyanobacteria. Structural changes occur when the OCPo absorbs a strong blue-green light leading to a red active form (OCPr). The N-terminal domain of OCPr burrows into the two external trimers of the core basal APC cylinders of the PB and increases thermal energy dissipation at the level of antenna. The OCP has an additional function in photoprotection as oxygen singlet quencher protecting cells from oxidative stress. Under low light conditions, to recover the full antenna capacity, a second protein is needed, the "Fluorescence Recovery Protein" (FRP), whose role is to detach the OCPr from the PB and accelerate its conversion into an inactive OCPo. In this manuscript, I will review the knowledge about the OCP, since the discovery of the mechanism and its characterization to the latest advances on the OCP-related-NPQ mechanism in cyanobacteria
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Livres sur le sujet "Non photochemical quencing"

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Demmig-Adams, Barbara, Gyozo Garab, William Adams III et Govindjee, dir. Non-Photochemical Quenching and Energy Dissipation in Plants, Algae and Cyanobacteria. Dordrecht : Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9032-1.

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Demmig-Adams, Barbara, Govindjee, Gyozo Garab et William Adams III. Non-Photochemical Quenching and Energy Dissipation in Plants, Algae and Cyanobacteria. Ingramcontent, 2014.

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Demmig-Adams, Barbara, Govindjee, William Adams III et Gyözö Garab. Non-Photochemical Quenching and Energy Dissipation in Plants, Algae and Cyanobacteria. Springer, 2014.

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Demmig-Adams, Barbara, Govindjee, Gyozo Garab et Adams William III. Non-Photochemical Quenching and Energy Dissipation in Plants, Algae and Cyanobacteria. Springer Netherlands, 2016.

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Chapitres de livres sur le sujet "Non photochemical quencing"

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Brooks, Matthew D., Stefan Jansson et Krishna K. Niyogi. « PsbS-Dependent Non-Photochemical Quenching ». Dans Advances in Photosynthesis and Respiration, 297–314. Dordrecht : Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9032-1_13.

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Krüger, Tjaart P. J., Cristian Ilioaia, Peter Horton, Maxime T. A. Alexandre et Rienk van Grondelle. « How Protein Disorder Controls Non-Photochemical Fluorescence Quenching ». Dans Advances in Photosynthesis and Respiration, 157–85. Dordrecht : Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9032-1_6.

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Manca, Vincenzo, Roberto Pagliarini et Simone Zorzan. « Toward an MP Model of Non-Photochemical Quenching ». Dans Membrane Computing, 299–310. Berlin, Heidelberg : Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-95885-7_22.

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Abasova, Leyla, Clemence Boulay, Imre Vass et Diana Kirilovsky. « Non-photochemical-quenching Mechanisms in the Cyanobacterium Thermosynechococcus elongatus ». Dans Photosynthesis. Energy from the Sun, 993–96. Dordrecht : Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6709-9_216.

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Büchel, Claudia. « Fucoxanthin-Chlorophyll-Proteins and Non-Photochemical Fluorescence Quenching of Diatoms ». Dans Advances in Photosynthesis and Respiration, 259–75. Dordrecht : Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9032-1_11.

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Demmig-Adams, Barbara, Seok-Chan Koh, Christopher M. Cohu, Onno Muller, Jared J. Stewart et William W. Adams. « Non-Photochemical Fluorescence Quenching in Contrasting Plant Species and Environments ». Dans Advances in Photosynthesis and Respiration, 531–52. Dordrecht : Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9032-1_24.

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Polívka, Tomáš, et Harry A. Frank. « Spectroscopic Investigation of Carotenoids Involved in Non-Photochemical Fluorescence Quenching ». Dans Advances in Photosynthesis and Respiration, 203–27. Dordrecht : Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9032-1_8.

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Melø, Thor Bernt. « Non-Photochemical Fluorescence Quenching in Avena Sativa at Subambient Temperatures ». Dans Photosynthesis : Mechanisms and Effects, 2293–96. Dordrecht : Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_537.

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Kaňa, Radek, Eva Kotabová et Ondřej Prášil. « Presence of Flexible Non-Photochemical Quenching in Cryptophytes (Rhodomonas Salina) ». Dans Advanced Topics in Science and Technology in China, 489–92. Berlin, Heidelberg : Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-32034-7_103.

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D’Ambrosio, N., C. R. Guadagno et A. Virzo De Santo. « Is qE Always the Major Component of Non-photochemical Quenching ? » Dans Photosynthesis. Energy from the Sun, 1001–4. Dordrecht : Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6709-9_218.

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Actes de conférences sur le sujet "Non photochemical quencing"

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Sukhova, E. M., et V. S. Sukhov. « Optical model of the distribution of non-photochemical quenching in a sheet ». Dans IX Congress of society physiologists of plants of Russia "Plant physiology is the basis for creating plants of the future. Kazan University Press, 2019. http://dx.doi.org/10.26907/978-5-00130-204-9-2019-421.

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de la Cruz Valbuena, Gabriel Jose, Franco Valduga De Almeida Camargo, Rocio Borrego Varillas, Federico Perozeni, Cosimo DaAndrea, Matteo Ballottari et Giulio Cerullo. « Molecular Mechanism of Non-Photochemical Quenching in LHCSR3 Protein of Chlamydomonas Reindhartii ». Dans 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC). IEEE, 2019. http://dx.doi.org/10.1109/cleoe-eqec.2019.8872630.

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Amarie, Sergiu, Andreas Dreuw, Josef Wachtveitl, Tiago Barros, Jörg Standfuss et Werner Kühlbrandt. « Molecular basis of Non-Photochemical Quenching (NPQ) ; The Role of the Major Light-Harvesting Complex LHC II ». Dans International Conference on Ultrafast Phenomena. Washington, D.C. : OSA, 2006. http://dx.doi.org/10.1364/up.2006.mh11.

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