Artículos de revistas: "Thylakoid pigment"

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Takeuchi, TS y JP Thornber. "Heat-Induced Alterations in Thylakoid Membrane Protein Composition in Barley". Functional Plant Biology 21, n.º 6 (1994): 759. http://dx.doi.org/10.1071/pp9940759.

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Biochemical and spectroscopic studies on the effects of high temperatures (45-47� C) over a 1 h period on the protein composition, fluorescence and photochemical activities of the barley thylakoid membrane were made. Photosystem II (PS II) activity decreased as expected, and photosystem I (PS I) activity also unexpectedly decreased. Our data support previous conclusions that the decrease in PS I activity is largely due to inactivation (or loss) of a component between the two photosystems. A two-dimensional electrophoretic system permitted first the separation of the thylakoid pigment-protein complexes of unstressed and stressed plants, followed by a determination of their subunit composition. The changes in the protein composition of each pigment-protein complex in response to elevated temperatures were monitored. Heat changed the quaternary structure of PS II and resulted in removal of the oxygen-evolving enhancer proteins from the thylakoid, but did essentially no damage to the PS I complex. The PS II core complex dissociated from a dimeric form to a monomeric one, and the major LHC II component (LHC IIb) changed from a trimeric to a monomeric form. The pigments that are lost from thylakoids during heat stress are mainly removed from the PS II pigment-proteins.

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Ghoshroy, Soumitra y Wayne R. Fagerberg. "Light-detection system in higher-plant chloroplasts : Pigment mediated or energy related". Proceedings, annual meeting, Electron Microscopy Society of America 50, n.º 2 (agosto de 1992): 1668–69. http://dx.doi.org/10.1017/s0424820100132972.

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Light is the driving force of photosynthesis. Plants adapt to rapid changes in irradiance, quality and duration of the light environment by modulating the composition of the thylakoid membranes to make the best use of the available light energy. Each chloroplast contains a large amount of thylakoid membranes some of which may be arranged as stacks (granal thylakoids) and others as unstacked sacks (stromal thylakoids). Shaded chloroplasts develop more thylakoid surface area as compared to those growing in full sunlight. Conversion of sun-type chloroplasts to those of shade-types can occur quickly, when sun plants are shaded. However, the response mechanism of chloroplasts to changes in light levels is yet to be understood. Reports in the literature showed that plants grown in red light developed more grana compared to those grown under blue light and a pigment detection system has been postulated. While, other models propose that overall energy flux changes within the chloroplast induce sun/shade response.

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Yi-Bin, Wang, Liu Fang-Ming, Zhang Xiu-Fang, Zhang Ai-Jun, Wang Bin, Zheng Zhou, Sun Cheng-Jun y Miao Jin-Lai. "Composition and regulation of thylakoid membrane of Antarctic ice microalgae Chlamydomonas sp. ICE-L in response to low-temperature environment stress". Journal of the Marine Biological Association of the United Kingdom 97, n.º 6 (6 de mayo de 2016): 1241–49. http://dx.doi.org/10.1017/s0025315416000588.

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Ice algae have successfully adapted to the extreme environmental conditions in the Antarctic, however the underlying mechanisms involved in the regulation and response of thylakoid membranes and chloroplast to low-temperature stress are still not well understood. In this study, changes in pigment concentrations, lipids, fatty acids and pigment protein complexes in thylakoid membranes and chloroplast after exposure to low temperature conditions were investigated using the Antarctic ice algae Chlamydomonas sp. ICE-L. Results showed that the chloroplasts of Chlamydomonas sp. ICE-L are distributed throughout the cell except in the nuclear region in the form of thylakoid lamellas which exists in the gap between organelles and the starch granules. Also, the structure of mitochondria has no obvious change after cold stress. Concentrations of Chl a, Chl b, monogalactosyl diacylglycerol, digalactosyl diacylglycerol and fatty acids were also observed to exhibit changes with temperature, suggesting possible adaptations to cold environments. The light harvesting complex, lutein and β-carotene played an important role for adaptation of ICE-L, and increasing of monogalactosyl diacylglycerol and digalactosyl diacylglycerol improved the overall degree of unsaturation of thylakoid membranes, thereby maintaining liquidity of thylakoid membranes. The pigments, lipids, fatty acids and pigment-protein complexes maintained the stability of the thylakoid membranes and the normal physiological function of Chlamydomonas sp. ICE-L.

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Carpentier, Robert, Roger M. Leblanc y Guy Bellemare. "Chlorophyll Photobleaching in Pigment-Protein Complexes". Zeitschrift für Naturforschung C 41, n.º 3 (1 de marzo de 1986): 284–90. http://dx.doi.org/10.1515/znc-1986-0307.

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Pigment photobleaching was performed in thylakoid membranes of Hordeum vulgare (wild type, mutant Chlorina f2, Norfluranzon treated seedlings) and in pigment-protein complexes (CP-I and LHCP) isolated from H. vulgare and Chlamydomonas reinhardtii. Multiphasic kinetics were obtained in all of the above cases. Energy transfer towards pigments absorbing at longer wavelength is postulated as a general protection mechanism against photobleaching. This mechanism explains a substantial bleaching of carotenoids and a faster bleaching of chlorophyll aggregates, absorbing at long wavelength. These conclusions were valid for isolated complexes as well as for thylakoid membranes, although membranes were less sensitive to light.

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Moisan, Tiffany A., Mark Ellisman y Gina Sosinsky. "Chloroplast Ultrastructure And Absorption Properties Of The Alga Phaeocystis Antarctica Karsten: A Qualitative Study Using Electron Tomography". Microscopy and Microanalysis 5, S2 (agosto de 1999): 1258–59. http://dx.doi.org/10.1017/s1431927600019619.

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Understanding the light-harvesting properties of algae and higher plants are a fundamental topic in photosynthesis research. Much oceanographic research has focused on characterizing the in vivo chlorophyll-specific absorption coefficient, a*ph (λ) in phytoplankton because it serves as an input variable for bio-optical modeling of photosynthesis using remote sensing instrumentation such as moorings, drifters, and satellites. Values of a*ph (λ) vary spectrally and the magnitude depends on accessory pigments, photo-protective pigments, and pigment packaging effects. Several studies have shown that the contribution of cellular characteristics to a*ph(λ) varies with growth conditions including temperature, light, and nutrients. It has been shown that a*ph (λ) values in Phaeocystis vary predictably at 4°C over light intensities under light limitation. Phaeocystis demonstrated significant pigment package effects that depended on single cell diameter and thylakoid membrane stacking. Using thick sections obtained from fixed and embedded cultures of colonial P. antarctica, we calculated tomographic reconstructions of individual chloroplasts under light-limiting conditions for net photosynthesis in order to gain an understanding of the continuity of thylakoid membranes and understand the spatial relationship between the pyrenoid, the starch containing organelle, and thylakoid membranes.

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Freeman, Thomas, Murray Duysen, Ken Eskins y James Guikema. "Thylakoid membrane development in pigment-deficient wheat chloroplasts". Proceedings, annual meeting, Electron Microscopy Society of America 49 (agosto de 1991): 214–15. http://dx.doi.org/10.1017/s042482010008537x.

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The thylakoid membranes of higher plant chloroplasts contain at least two major pigment protein complexes, photosystem I (PSI), and photosystem II (PSII). The mature apoprotein of these complexes (involved in the initial reactions of photosynthesis) bind specific chlorophylls (Chl) and specific carotenoids in an unknown manner. It has been suggested, however, that the synthesis of pigments is normally coordinated with that of apoproteins. We have examined the effect of gabaculine (3-amino-2, 3-dihydrobenzoic acid) on granal thylakoid stacking as well as pigment and apoprotein accumulations for PSI and PSII in wheat.Gabaculine (0.5mM) was applied with nutrient solution to 6.5 day-old wheat seedlings maintained in a growth chamber at 23C. One seedling lot grown under continuous light (400 μmol photons s-1 m-2) possessed green primary leaves at time of treatment whereas another seedling lot, dark grown, possessed only etiolated primary leaves. Twelve hours after treatment, the etiolated seedlings were transferred into continuous light. The primary and secondary leaves were subsequently harvested from 14 day-old seedlings of both lots.

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Luciński, Robert y Grzegorz Jackowski. "The structure, functions and degradation of pigment-binding proteins of photosystem II." Acta Biochimica Polonica 53, n.º 4 (14 de noviembre de 2006): 693–708. http://dx.doi.org/10.18388/abp.2006_3297.

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Eleven proteins belonging to photosystem II (PSII) bind photosynthetic pigments in the form of thylakoid membrane-associated pigment-protein complexes. Five of them (PsbA, PsbB, PsbC, PsbD and PsbS) are assigned to PSII core complex while the remaining six (Lhcb1, Lhcb2, Lhcb3, Lhcb4, Lhcb5 and Lhcb6) constitute, along with their pigments, functional complexes situated more distantly with regard to P680 - the photochemical center of PSII. The main function of the pigment-binding proteins is to harvest solar energy and deliver it, in the form of excitation energy, ultimately to P680 although individual pigment-proteins may be engaged in other photosynthesis-related processes as well. The aim of this review is to present the current state of knowledge regarding the structure, functions and degradation of this family of proteins.

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8

Kaňa, Radek, Gábor Steinbach, Roman Sobotka, György Vámosi y Josef Komenda. "Fast Diffusion of the Unassembled PetC1-GFP Protein in the Cyanobacterial Thylakoid Membrane". Life 11, n.º 1 (29 de diciembre de 2020): 15. http://dx.doi.org/10.3390/life11010015.

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Biological membranes were originally described as a fluid mosaic with uniform distribution of proteins and lipids. Later, heterogeneous membrane areas were found in many membrane systems including cyanobacterial thylakoids. In fact, cyanobacterial pigment–protein complexes (photosystems, phycobilisomes) form a heterogeneous mosaic of thylakoid membrane microdomains (MDs) restricting protein mobility. The trafficking of membrane proteins is one of the key factors for long-term survival under stress conditions, for instance during exposure to photoinhibitory light conditions. However, the mobility of unbound ‘free’ proteins in thylakoid membrane is poorly characterized. In this work, we assessed the maximal diffusional ability of a small, unbound thylakoid membrane protein by semi-single molecule FCS (fluorescence correlation spectroscopy) method in the cyanobacterium Synechocystis sp. PCC6803. We utilized a GFP-tagged variant of the cytochrome b6f subunit PetC1 (PetC1-GFP), which was not assembled in the b6f complex due to the presence of the tag. Subsequent FCS measurements have identified a very fast diffusion of the PetC1-GFP protein in the thylakoid membrane (D = 0.14 − 2.95 µm2s−1). This means that the mobility of PetC1-GFP was comparable with that of free lipids and was 50–500 times higher in comparison to the mobility of proteins (e.g., IsiA, LHCII—light-harvesting complexes of PSII) naturally associated with larger thylakoid membrane complexes like photosystems. Our results thus demonstrate the ability of free thylakoid-membrane proteins to move very fast, revealing the crucial role of protein–protein interactions in the mobility restrictions for large thylakoid protein complexes.

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9

Sridharan, Govindachary, Simon Gaudreau, Laetitia Dalstein, Christelle Huiban, Agnès Lejeune y Mário Fragata. "Effect of α-, β-and γ-Cyclodextrins on Oxygen Evolution by the Thylakoid Membrane. Influence of pH and Temperature". Zeitschrift für Naturforschung C 56, n.º 9-10 (1 de octubre de 2001): 792–802. http://dx.doi.org/10.1515/znc-2001-9-1018.

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AbstractThe present work investigates the effect of α-, β- and γ-cyclodextrins (CD), i.e., α-CD, β- CD and γ-CD, on the oxygen evolution activity, the protein content and the uv-vis spectroscopic characteristics of thylakoid membranes. To study the pH-dependence, the thylakoids were incubated with the cyclodextrins at 273 K for a period of 10 min in the pH range from 5.5 to 9.0. To study the temperature-dependence the membranes were incubated at 273 and 293 K at pH 6.5, that is, the pH which induces a maximal oxygen evolution in the thylakoid preparations. The major observations are: (i) a stimulation of oxygen evolution in thylakoids incubated with α- and β-CD either in acidic or alkaline conditions, (ii) a low inhibitory effect induced by γ-CD on oxygen evolution, (iii) a significant decrease of the stimulatory effect of α- and β-CD on oxygen evolution as the incubation temperature is raised from 273 to 293 K, (iv) the apparent inability of the cyclodextrins to change the protein contents of the thylakoids, and (v) a significant CD-induced red-shift from 681 to 683 nm observed in the absorption and second derivative spectra of the thylakoid membranes treated with β-CD. First, it was found that the temperature effect described here is in accord with the general trend of the chemical effect of various cyclodextrins, i.e., the increase of the CD efficiency with decreasing temperature. Secondly, the CD effect is related to the size of the inner cavity diameter of the cyclodextrin molecules. An important conclusion in this work is that the molecular targets of the cyclodextrins are not limited to the thylakoid lipids as was described previously [Rawyler A. and Siegenthaler P.A. (1996) Biochim. Biophys. Acta 1278, 89-97], but are located as well in other molecular species exposed at the stromal side of the thylakoid membrane. In particular, the CD-induced red-shift from 681 to 683 nm in the absorption and second derivative spectra of the thylakoid membranes indicates that the cyclodextrins targets might be either the exposed heme macrocycle in cytochrome b559, or the chlorophylls and pheophytins in the pigment-proteins of the photosystems I and II.

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Chandra, Rosita Dwi, Renny Indrawati, Heriyanto Heriyanto, Tatas H. P. Brotosudarmo y Leenawaty Limantara. "Isolation, Encapsulation, Stability and Characteristics of Thylakoid from Suji Leaves (Pleomele angustifolia) as Natural Food Coloring Agent". Indonesian Journal of Natural Pigments 1, n.º 2 (3 de septiembre de 2019): 53. http://dx.doi.org/10.33479/ijnp.2019.01.2.53.

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Suji (Pleomele angustifolia) is one kind of Indonesian typical plants which can be used as natural green food coloring agent. The susceptibility of natural pigment to external environment forces the protection in order to prolong its shelf life. Encapsulation has been known in the art of food preparation to provide protection for several ingredients including food coloring agent. The objective of this study was to observe the method for isolation and encapsulation of thylakoid, and to investigate the stability and characteristics of thylakoid of suji leaves encapsulated in maltodextrin during dark storage at 30 °C, 45 °C, and 60 °C. The degradation of the encapsulated pigments was identified through chromametric analysis which resulted in the increase of L* (lightness), a* (redness), and b* (yellowness) values. In addition, it was also indicated by the decrease of total chlorophyll (TC) which was determined using spectrophotometer. Chromatography analysis confirmed the presence of four major peaks in the fresh encapsulated thylakoid powder and five major peaks in the encapsulated thylakoid powder stored at the highest temperature (60 °C), with Chl a as the dominant pigments in both powder. The vivid green powder was able to preserve its color without any obvious change to an untrained eye up to 60 d of storage at 30 °C, becoming a promising ingredient to replace the synthetic colorants.

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11

Krasnovsky, A. A. "Singlet molecular oxygen and primary mechanisms of photo-oxidative damage of chloroplasts. Studies based on detection of oxygen and pigment phosphorescence". Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 102 (1994): 219–35. http://dx.doi.org/10.1017/s0269727000014147.

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SynopsisPhotogeneration of singlet oxygen molecules (1O2), their vibrationally excited stateand dimols (1O2)2has been shown by measuring photosensitised delayed luminescence in pigment-containing media. All singlet oxygen species are formed as a result of energy transfer to O2from triplet pigment molecules. Monomeric pigment molecules are the most efficient singlet oxygen generators. The1O2quantum yields are 40–80% in aerobic solutions of monomeric chlorophylls and pheophytins. Pigment aggregation causes a strong decrease in singlet oxygen production. The1O2quantum yield in chloroplasts has been estimated using literature and experimental data on formation of the chlorophyll triplet states in the photosynthetic apparatus. The most probable value is 0.1%. One of the major sources of singlet oxygen is likely to be the triplet states of newly formed pigment molecules which are not quenched by carotenoids and can be detected by measuring low-temperature pigment phosphorescence. Quenching of singlet oxygen by the thylakoid components has been analysed and the1O2lifetime estimated. The data suggest that carotenoids and chlorophylls are the most efficient physical1O2quenchers and the1O2lifetime is about 70 ns in thylakoids. The quantum yield of1O2-induced pigment photodestruction was estimated to be about 10−6–10−5. This value is close to the quantum yield of chlorophyll photobleaching experimentally observed in aerobic suspensions of isolated chloroplasts. The intensity of pigment phosphorescence at 77 K correlates with the rate of chlorophyll photobleaching in plant materials. The data suggest that1O2generation by the pigment triplet states is the most likely reason for chloroplast photodamage. The intensity of pigment phosphorescence can be used as an index of the degree of plant photo-oxidative stress.

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Bashir, Faiza, Ateeq Ur Rehman, Milán Szabó y Imre Vass. "Singlet oxygen damages the function of Photosystem II in isolated thylakoids and in the green alga Chlorella sorokiniana". Photosynthesis Research 149, n.º 1-2 (19 de mayo de 2021): 93–105. http://dx.doi.org/10.1007/s11120-021-00841-3.

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AbstractSinglet oxygen (1O2) is an important damaging agent, which is produced during illumination by the interaction of the triplet excited state pigment molecules with molecular oxygen. In cells of photosynthetic organisms 1O2 is formed primarily in chlorophyll containing complexes, and damages pigments, lipids, proteins and other cellular constituents in their environment. A useful approach to study the physiological role of 1O2 is the utilization of external photosensitizers. In the present study, we employed a multiwell plate-based screening method in combination with chlorophyll fluorescence imaging to characterize the effect of externally produced 1O2 on the photosynthetic activity of isolated thylakoid membranes and intact Chlorella sorokiniana cells. The results show that the external 1O2 produced by the photosensitization reactions of Rose Bengal damages Photosystem II both in isolated thylakoid membranes and in intact cells in a concentration dependent manner indicating that 1O2 plays a significant role in photodamage of Photosystem II.

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Zuo, Lihui, Shuang Zhang, Yichao Liu, Yinran Huang, Minsheng Yang y Jinmao Wang. "The Reason for Growth Inhibition of Ulmus pumila ‘Jinye’: Lower Resistance and Abnormal Development of Chloroplasts Slow Down the Accumulation of Energy". International Journal of Molecular Sciences 20, n.º 17 (29 de agosto de 2019): 4227. http://dx.doi.org/10.3390/ijms20174227.

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Ulmus pumila ‘Jinye’, the colorful leaf mutant of Ulmus pumila L., is widely used in landscaping. In common with most leaf color mutants, U. pumila ‘Jinye’ exhibits growth inhibition. In this study, U. pumila L. and U. pumila ‘Jinye’ were used to elucidate the reasons for growth inhibition at the physiological, cellular microstructural, and transcriptional levels. The results showed that the pigment (chlorophyll a, chlorophyll b, and carotenoids) content of U. pumila L. was higher than that of U. pumila ‘Jinye’, whereas U. pumila ‘Jinye’ had a higher proportion of carotenoids, which may be the cause of the yellow leaves. Examination of the cell microstructure and RNA sequencing analysis showed that the leaf color and growth inhibition were mainly due to the following reasons: first, there were differences in the structure of the thylakoid grana layer. U. pumila L. has a normal chloroplast structure and clear thylakoid grana slice layer structure, with ordered and compact thylakoids. However, U. pumila ‘Jinye’ exhibited the grana lamella stacking failures and fewer thylakoid grana slice layers. As the pigment carrier and the key location for photosynthesis, the close stacking of thylakoid grana could combine more chlorophyll and promote efficient electron transfer promoting the photosynthesis reaction. In addition, U. pumila ‘Jinye’ had a lower capacity for light energy absorption, transformation, and transportation, carbon dioxide (CO2) fixation, lipopolysaccharide biosynthesis, auxin synthesis, and protein transport. The genes related to respiration and starch consumption were higher than those of U. pumila L., which indicated less energy accumulation caused the growth inhibition of U. pumila ‘Jinye’. Finally, compared with U. pumila ‘Jinye’, the transcription of genes related to stress resistance all showed an upward trend in U. pumila L. That is to say, U. pumila L. had a greater ability to resist adversity, which could maintain the stability of the intracellular environment and maintain normal progress of physiological metabolism. However, U. pumila ‘Jinye’ was more susceptible to changes in the external environment, which affected normal physiological metabolism. This study provides evidence for the main cause of growth inhibition in U. pumila ‘Jinye’, information for future cultivation, and information on the mutation mechanism for the breeding of colored leaf trees.

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Doltchinkova, Virjinia R., Katia Georgieva, Veneta Kapchina-Toteva y Juergen Polle. "Electrokinetic properties of thylakoids in in vitro cultured Gypsophila paniculata plants". Functional Plant Biology 27, n.º 11 (2000): 1085. http://dx.doi.org/10.1071/pp99042.

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In vitro cultured Gypsophila paniculata L. plants were used as a model to evaluate the effect of some cytokinins and anticytokinins on thylakoid surface charge. Influence of the cytokinins N-6-furfurylaminopurine (kinetin) and N1-(2-chloro-4-pyridyl)-N2-phenylurea (4-PU-30), cytokinin antagonists 2-chloro-4-cyclobutylamino-6-ethylamino-1,3,5-triazine and N-(4-pyridyl)-O-(4-chlorophenyl) carbamate on the pigment content, surface charge density (s ), fluorescence induction kinetics and millisecond-delayed light emission was studied. Our results showed that the chlorophyll (a+b) content significantly decreased after the 1st and the 2nd month of G. paniculata growth in the presence of the cytokinins kinetin and 4-PU-30. In our model system, cytokinins enhanced the number of open lateral buds and, as a consequence, more shoots per explant. Hence, chlorophyll synthesis was not inhibited but so-called ‘dilution of the pigments’ was available. Anticytokinins inhibited the formation of more than one shoot, and the chlorophyll content was not influenced significantly. The phenylurea cytokinin 4-PU-30 and anticytokinins increased the electrophoretic mobility, zeta potential and surface charge density of thylakoids after a longer time of treatment. Making thylakoid membranes more negatively charged, phenylurea cytokinin and anticytokinins increased the aggregation of the complexes and the energization of the membrane. Our results showed that plant growth regulators decreased the primary photochemical activity of photosystem II (estimated by the ratio Fv/Fm) and delayed fluorescence intensity in the 1st month. However, no significant changes were observed in these parameters in the 2nd month.

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Lee, Tzan-Chain, Kuan-Hung Lin, Meng-Yuan Huang y Chi-Ming Yang. "Glucose Induces Thylakoid Formation and Upregulates Green Pigment Contents in Complete Dark Culture of the Angiosperm Pachiramacrocarpa". Agronomy 11, n.º 9 (30 de agosto de 2021): 1746. http://dx.doi.org/10.3390/agronomy11091746.

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In addition to angiosperms, most plants are able to synthesize chlorophyll (Chl)-generating green tissues in total darkness. In this study, 140 plants of the angiosperm Pachira macrocarpa were divided into five groups. Among them, one group was grown for 2 weeks under natural light conditions, whereas the others were grown in complete darkness (0 μmol m−2 s−1). Dark-grown plants were then treated with 0~6% glucose for another 8 weeks. The budding and greening ratios, ultrastructure of chloroplasts (ChlPs) of newly developed leaves, and green pigment contents of pre-illuminated mature and young leaves, and totally dark-grown newly developed leaves were measured. Results showed that glucose inhibited the budding and promoted the greening of newly developed leaves. Pre-illuminated mature and young leaves were able to synthesize green pigments during the 2 weeks of dark adaption. Dark-grown newly developed leaves contained high levels of green pigments at 2 and 3 weeks after budding. Green pigments of glucose-fed newly developed leaves had increased, whereas they had decreased in control leaves. In addition, ChlPs of dark-grown glucose-fed newly developed leaves contained both giant grana and prolamellar bodies (PLBs), usually found in shade plants and etiolated seedlings, respectively. The higher the glucose concentration was, the greater the numbers of grana, thylakoids, and PLBs. Glucose increased the green pigment contents and grana formation in newly developed leaves in a dark condition, and the mechanisms are discussed.

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Dymova, Olga, Mikhail Khristin, Zbigniew Miszalski, Andrzej Kornas, Kazimierz Strzalka y Tamara Golovko. "Seasonal variations of leaf chlorophyll–protein complexes in the wintergreen herbaceous plant Ajuga reptans L." Functional Plant Biology 45, n.º 5 (2018): 519. http://dx.doi.org/10.1071/fp17199.

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The chlorophyll and carotenoid content, and the spectra of low-temperature fluorescence of the leaves, chloroplasts and isolated pigment–protein complexes in the perennial herbaceous wintergreen plant Ajuga reptans L. (bugle) in different seasons of the year were studied. During winter, these plants downregulate photosynthesis and the PSA is reorganised, including the loss of chlorophyll, possible reductions in the number of functional reaction centres of PSII, and changes in aggregation of the thylakoid protein complexes. We also observed a restructuring of the PSI–PSII megacomplex and the PSII–light-harvesting complex II supercomplex in leaves covered by snow. After snowmelt, the monomeric form of the chl a/b pigment–protein complex associated with PSII (LHCII) and the free pigments were also detected. We expect that snow cover provides favourable conditions for keeping photosynthetic machinery ready for photosynthesis in spring just after snowmelt. During winter, the role of the zeaxanthin-dependent protective mechanism, which is responsible for the dissipation of excess absorbed light energy, is likely to increase.

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Whyte, B. J. y P. A. Castelfranco. "Breakdown of thylakoid pigments by soluble proteins of developing chloroplasts". Biochemical Journal 290, n.º 2 (1 de marzo de 1993): 361–67. http://dx.doi.org/10.1042/bj2900361.

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In the presence of Triton X-100 (TX-100) or imazalil, plastidic pigments were degraded by a soluble enzyme extracted from developing chloroplasts. This bleaching was not photochemical and required oxygen; it was not inhibited by superoxide dismutase or catalase, but was strongly inhibited by benzoquinone, quinol, phenazine methosulphate and, more weakly, by other reagents. Synthetic intermediates of chlorophyll biosynthesis, e.g. Mg(II)-protoporphyrin IX monomethyl ester, was also degraded. This reaction was compared with the bleaching catalysed by soybean (Glycine max) lipoxygenase. The plastidic system required TX-100 and was inhibited by unsaturated fatty acids, whereas lipoxygenase required a polyunsaturated fatty acid and was inhibited by TX-100. The bleaching capability of the stromal extract decreased with age if the seedlings were placed in the greenhouse to allow further development of the chloroplasts. A direct relationship was observed between the promotion of pigment bleaching by TX-100 and the inhibition of the in vitro synthesis of divinylprotochlorophyllide. This bleaching reaction is discussed on the basis of interference by TX-100 with the normal O2-requiring anabolic processes of developing chloroplasts.

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Chesalin, Denis D. y Roman Y. Pishchalnikov. "Photosynthetic pigment-protein complexes optical response modeling optimized by Differential evolution: algorithm convergence study". Journal of Physics: Conference Series 2090, n.º 1 (1 de noviembre de 2021): 012028. http://dx.doi.org/10.1088/1742-6596/2090/1/012028.

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Abstract Photosynthetic pigment-protein complexes are the essential parts of thylakoid membranes of higher plants and cyanobacteria. Besides many organic and inorganic molecules they contain pigments like chlorophyll, bacteriochlorophyll, and carotenoids, which absorb the incident light and transform it into the energy of the excited electronic states. The semiclassical theories such as molecular exciton theory and the multimode Brownian oscillator model allows us to simulate the linear and nonlinear optical response of any pigment-protein complex, however, the main disadvantage of those approaches is a significant amount of effective parameters needed to be found in order to reproduce the experimental data. To overcome these difficulties we used the Differential evolution method (DE) that belongs to the family of evolutionary optimization algorithms. Based on our preliminary studies of the linear optical properties of monomeric photosynthetic pigments using DE, we proceed to more complex systems like the reaction center of photosystem II isolated from higher plants (PSIIRC). PSIIRC contains only eight chlorophyll pigments, and therefore it is potentially a very promising subject to test DE as a powerful optimization procedure for simulation of the optical response of a system of interacting pigments. Using the theoretically simulated linear spectra of PSIIRC (absorption, circular dichroism, linear dichroism, and fluorescence), we investigated the dependence of the algorithm convergence on DE settings: strategies, crossover, weighting factor; eventually finding the optimal mode of operation of the optimization procedure.

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Fujii, Wada y Kobayashi. "Role of Galactolipids in Plastid Differentiation Before and After Light Exposure". Plants 8, n.º 10 (20 de septiembre de 2019): 357. http://dx.doi.org/10.3390/plants8100357.

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Galactolipids, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), are the predominant lipid classes in the thylakoid membrane of chloroplasts. These lipids are also major constituents of internal membrane structures called prolamellar bodies (PLBs) and prothylakoids (PTs) in etioplasts, which develop in the cotyledon cells of dark-grown angiosperms. Analysis of Arabidopsis mutants defective in the major galactolipid biosynthesis pathway revealed that MGDG and DGDG are similarly and, in part, differently required for membrane-associated processes such as the organization of PLBs and PTs and the formation of pigment–protein complexes in etioplasts. After light exposure, PLBs and PTs in etioplasts are transformed into the thylakoid membrane, resulting in chloroplast biogenesis. During the etioplast-to-chloroplast differentiation, galactolipids facilitate thylakoid membrane biogenesis from PLBs and PTs and play crucial roles in chlorophyll biosynthesis and accumulation of light-harvesting proteins. These recent findings shed light on the roles of galactolipids as key facilitators of several membrane-associated processes during the development of the internal membrane systems in plant plastids.

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20

Young, Andrew, Paul Barry y George Britton. "The Occurrence of β-Carotene-5,6-epoxide in the Photosynthetic Apparatus of Higher Plants". Zeitschrift für Naturforschung C 44, n.º 11-12 (1 de diciembre de 1989): 959–65. http://dx.doi.org/10.1515/znc-1989-11-1214.

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Abstract The occurrence of β-carotene-5,6-epoxide in higher plant photosynthetic tissue is described. The compound is found in isolated chloroplasts, thylakoids and other subchloroplast particles but can only be detected in intact leaves or cotyledons of higher plants when these are exposed to very high light intensities or to inhibitors such as monuron or paraquat. The distribution of the epoxide within the individual pigment-protein complexes is given. It is particularly associated with the PS I reaction centres (C P I and CP la) and less so with the PS II reaction centre (CPa). Circular dichroism shows that the β-carotene-5,6-epoxide isolated from photosynthetic tissue is optically inactive. It is therefore not produced enzymically but is a product of photooxidative events in the photosynthetic apparatus. Its presence in photosynthetic tissue is a reliable indicator of photooxidative damage to the thylakoid membrane involving oxidation of β-carotene.

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21

Shevchenko, V. V., O. Yu Bondarenko y D. Yu Kornyeyev. "Short-term heating causes thylakoid restructuring in pea chloroplasts and modifies spectral properties of pigment-protein complexes". Fiziologia rastenij i genetika 54, n.º 2 (abril de 2022): 134–47. http://dx.doi.org/10.15407/frg2022.02.134.

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22

Taran, N. Yu, I. P. Ozheredova, V. O. Storozhenko, N. B. Svetlova y N. M. Topchiy. "Pigment-protein complexes of thylakoid membranes of Deschampsia antarctica Desv. plants". Ukrainian Antarctic Journal, n.º 9 (2010): 202–5. http://dx.doi.org/10.33275/1727-7485.9.2010.405.

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23

Cho, Sung Ho y Guy A. Thompson. "Galactolipids of Thylakoid Pigment Protein Complexes Separated Electrophoretically from Thylakoids of Dunaliella salina Labeled with Radioactive Fatty Acids". Plant Physiology 90, n.º 2 (1 de junio de 1989): 610–16. http://dx.doi.org/10.1104/pp.90.2.610.

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24

Lehto, Kirsi, Mikko Tikkanen, Jean-Baptiste Hiriart, Virpi Paakkarinen y Eva-Mari Aro. "Depletion of the Photosystem II Core Complex in Mature Tobacco Leaves Infected by the Flavum Strain of Tobacco mosaic virus". Molecular Plant-Microbe Interactions® 16, n.º 12 (diciembre de 2003): 1135–44. http://dx.doi.org/10.1094/mpmi.2003.16.12.1135.

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The flavum strain of Tobacco mosaic virus (TMV) differs from the wild-type (wt) virus by causing strong yellow and green mosaic in the systemically infected developing leaves, yellowing in the fully expanded leaves, and distinct malformations of chloroplasts in both types of infected tissues. Analysis of the thylakoid proteins of flavum strain-infected tobacco leaves indicated that the chlorosis in mature leaves was accompanied by depletion of the entire photosystem II (PSII) core complexes and the 33-kDa protein of the oxygen evolving complex. The only change observed in the thyla-koid proteins of the corresponding wt TMV-infected leaves was a slight reduction of the α and β subunits of the ATP synthase complex. The coat proteins of different yellowing strains of TMV are known to effectively accumulate inside chloroplasts, but in this work, the viral movement protein also was detected in association with the thylakoid membranes of flavum strain-infected leaves. The mRNAs of different enzymes involved in the chlorophyll biosynthesis pathway were not reduced in the mature chlorotic leaves. These results suggest that the chlorosis was not caused by reduction of pigment biosynthesis, but rather, by reduction of specific proteins of the PSII core complexes and by consequent break-down of the pigments.

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25

Horton, Peter. "Optimization of light harvesting and photoprotection: molecular mechanisms and physiological consequences". Philosophical Transactions of the Royal Society B: Biological Sciences 367, n.º 1608 (19 de diciembre de 2012): 3455–65. http://dx.doi.org/10.1098/rstb.2012.0069.

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The distinctive lateral organization of the protein complexes in the thylakoid membrane investigated by Jan Anderson and co-workers is dependent on the balance of various attractive and repulsive forces. Modulation of these forces allows critical physiological regulation of photosynthesis that provides efficient light-harvesting in limiting light but dissipation of excess potentially damaging radiation in saturating light. The light-harvesting complexes (LHCII) are central to this regulation, which is achieved by phosphorylation of stromal residues, protonation on the lumen surface and de-epoxidation of bound violaxanthin. The functional flexibility of LHCII derives from a remarkable pigment composition and configuration that not only allow efficient absorption of light and efficient energy transfer either to photosystem II or photosystem I core complexes, but through subtle configurational changes can also exhibit highly efficient dissipative reactions involving chlorophyll–xanthophyll and/or chlorophyll–chlorophyll interactions. These changes in function are determined at a macroscopic level by alterations in protein–protein interactions in the thylakoid membrane. The capacity and dynamics of this regulation are tuned to different physiological scenarios by the exact protein and pigment content of the light-harvesting system. Here, the molecular mechanisms involved will be reviewed, and the optimization of the light-harvesting system in different environmental conditions described.

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26

Matsubara, Shizue, Britta Förster, Melinda Waterman, Sharon A. Robinson, Barry J. Pogson, Brian Gunning y Barry Osmond. "From ecophysiology to phenomics: some implications of photoprotection and shade–sun acclimation in situ for dynamics of thylakoids in vitro". Philosophical Transactions of the Royal Society B: Biological Sciences 367, n.º 1608 (19 de diciembre de 2012): 3503–14. http://dx.doi.org/10.1098/rstb.2012.0072.

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Half a century of research into the physiology and biochemistry of sun–shade acclimation in diverse plants has provided reality checks for contemporary understanding of thylakoid membrane dynamics. This paper reviews recent insights into photosynthetic efficiency and photoprotection from studies of two xanthophyll cycles in old shade leaves from the inner canopy of the tropical trees Inga sapindoides and Persea americana (avocado). It then presents new physiological data from avocado on the time frames of the slow coordinated photosynthetic development of sink leaves in sunlight and on the slow renovation of photosynthetic properties in old leaves during sun to shade and shade to sun acclimation. In so doing, it grapples with issues in vivo that seem relevant to our increasingly sophisticated understanding of Δ pH-dependent, xanthophyll-pigment-stabilized non-photochemical quenching in the antenna of PSII in thylakoid membranes in vitro .

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27

Andreeva, Atanaska, Katerina Stoitchkova, Mira Busheva, Emilia Apostolova, Zsuzsanna Várkonyi y Gyözö Garab. "Resonance Raman spectroscopy of xanthophylls in pigment mutant thylakoid membranes of pea". Biopolymers 74, n.º 1-2 (7 de abril de 2004): 87–91. http://dx.doi.org/10.1002/bip.20050.

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28

Swingley, Wesley D., Martin F. Hohmann-Marriott, Tien Le Olson y Robert E. Blankenship. "Effect of Iron on Growth and Ultrastructure of Acaryochloris marina". Applied and Environmental Microbiology 71, n.º 12 (diciembre de 2005): 8606–10. http://dx.doi.org/10.1128/aem.71.12.8606-8610.2005.

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ABSTRACT The cyanobacterial genus Acaryochloris is the only known group of oxygenic phototrophs that contain chlorophyll d rather than chlorophyll a as the major photosynthetic pigment. Studies on this organism are still in their earliest stages, and biochemical analysis has rapidly outpaced growth optimization. We have investigated culture growth of the major strains of Acaryochloris marina (MBIC11017 and MBIC10697) by using several published and some newly developed growth media. It was determined that heavy addition of iron significantly enhanced culture longevity. These high-iron cultures showed an ultrastructure with thylakoid stacks that resemble traditional cyanobacteria (unlike previous studies). These cultures also show a novel reversal in the pigment ratios of the photosystem II signature components chlorophyll a and pheophytin a, as opposed to those in previous studies.

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29

Huang, Wei-Tao, Yi-Zhi Xie, Xu-Feng Chen, Jiang Zhang, Huan-Huan Chen, Xin Ye, Jiuxin Guo, Lin-Tong Yang y Li-Song Chen. "Growth, Mineral Nutrients, Photosynthesis and Related Physiological Parameters of Citrus in Response to Nitrogen Deficiency". Agronomy 11, n.º 9 (16 de septiembre de 2021): 1859. http://dx.doi.org/10.3390/agronomy11091859.

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Limited data are available on the physiological responses of Citrus to nitrogen (N) deficiency. ‘Xuegan’ (Citrus sinensis (L.) Osbeck) and ‘Shantian pummelo’ (Citrus grandis (L.) Osbeck) seedlings were fertilized with nutrient solution at a N concentration of 0, 5, 10, 15 or 20 mM for 10 weeks. N deficiency decreased N uptake and N concentration in leaves, stems and roots and disturbed nutrient balance and homeostasis in plants, thus inhibiting plant growth, as well as reducing photosynthetic pigment levels and impairing thylakoid structure and photosynthetic electron transport chain (PETC) in leaves, hence lowering CO2 assimilation. The imbalance of nutrients intensified N deficiency’s adverse impacts on biomass, PETC, CO2 assimilation and biosynthesis of photosynthetic pigments. Citrus displayed adaptive responses to N deficiency, including (a) elevating the distributions of N and other elements in roots, as well as root dry weight (DW)/shoot DW ratio and root-surface-per-unit volume and (b) improving photosynthetic N use efficiency (PNUE). In general, N deficiency had less impact on biomass and photosynthetic pigment levels in C. grandis than in C. sinensis seedlings, demonstrating that the tolerance of C. grandis seedlings to N deficiency was slightly higher than that of C. sinensis seedlings, which might be related to the higher PNUE of the former.

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30

Nagarajan, Aparna, Mowei Zhou, Amelia Y. Nguyen, Michelle Liberton, Komal Kedia, Tujin Shi, Paul Piehowski et al. "Proteomic Insights into Phycobilisome Degradation, A Selective and Tightly Controlled Process in The Fast-Growing Cyanobacterium Synechococcus elongatus UTEX 2973". Biomolecules 9, n.º 8 (16 de agosto de 2019): 374. http://dx.doi.org/10.3390/biom9080374.

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Phycobilisomes (PBSs) are large (3–5 megadalton) pigment-protein complexes in cyanobacteria that associate with thylakoid membranes and harvest light primarily for photosystem II. PBSs consist of highly ordered assemblies of pigmented phycobiliproteins (PBPs) and linker proteins that can account for up to half of the soluble protein in cells. Cyanobacteria adjust to changing environmental conditions by modulating PBS size and number. In response to nutrient depletion such as nitrogen (N) deprivation, PBSs are degraded in an extensive, tightly controlled, and reversible process. In Synechococcus elongatus UTEX 2973, a fast-growing cyanobacterium with a doubling time of two hours, the process of PBS degradation is very rapid, with 80% of PBSs per cell degraded in six hours under optimal light and CO2 conditions. Proteomic analysis during PBS degradation and re-synthesis revealed multiple proteoforms of PBPs with partially degraded phycocyanobilin (PCB) pigments. NblA, a small proteolysis adaptor essential for PBS degradation, was characterized and validated with targeted mass spectrometry. NblA levels rose from essentially 0 to 25,000 copies per cell within 30 min of N depletion, and correlated with the rate of decrease in phycocyanin (PC). Implications of this correlation on the overall mechanism of PBS degradation during N deprivation are discussed.

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31

Timperio, A. M., G. M. D'Amici, C. Barta, F. Loreto y L. Zolla. "Proteomics, pigment composition, and organization of thylakoid membranes in iron-deficient spinach leaves". Journal of Experimental Botany 58, n.º 13 (26 de septiembre de 2007): 3695–710. http://dx.doi.org/10.1093/jxb/erm219.

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32

Ruizzo, Michael A., Robert Bertekap y Michael L. Mishkind. "Consequences of herbicide-induced pigment deficiencies on thylakoid membrane proteins of Chlamydomonas reinhardtii". Plant Science 81, n.º 1 (enero de 1992): 13–20. http://dx.doi.org/10.1016/0168-9452(92)90019-i.

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33

Agarwal, Rachna, Gururaj Maralihalli, V. Sudarsan, Sharmistha Dutta Choudhury, Rajesh Kumar Vatsa, Haridas Pal, Michael Melzer y Jayashree Krishna Sainis. "Differential distribution of pigment-protein complexes in the Thylakoid membranes of Synechocystis 6803". Journal of Bioenergetics and Biomembranes 44, n.º 4 (24 de mayo de 2012): 399–409. http://dx.doi.org/10.1007/s10863-012-9437-0.

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34

Coelho, L., J. Prince y T. G. Nolen. "Processing of defensive pigment in Aplysia californica: acquisition, modification and mobilization of the red algal pigment, r-phycoerythrin by the digestive gland." Journal of Experimental Biology 201, n.º 3 (1 de febrero de 1998): 425–38. http://dx.doi.org/10.1242/jeb.201.3.425.

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The marine snail Aplysia californica obtains its purple defensive ink exclusively from the accessory photosynthetic pigment r-phycoerythrin, which is found in the red seaweeds of its diet. The rhodoplast digestive cell, one of three types of cell lining the tubules of the digestive gland, appears to be the site of catabolism of red algal chloroplasts (rhodoplasts) since thylakoid membranes, including phycobilisome-sized membrane-associated particles, were found within the large digestive vacuoles of this cell. Immunogold localization showed that there was a statistically significant occurrence of the red algal phycobilisome pigment r-phycoerythrin within these rhodoplast digestive vacuoles, but not in other compartments of this cell type (endoplasmic reticulum, mitochondria, nucleus) or in other tissues (abdominal ganglion). Immunogold analysis also suggested that the rhodoplast vacuole is the site for additional modification of r-phycoerythrin, which makes it non-antigenic: the chromophore is either cleaved from its biliprotein or the biliprotein is otherwise modified. The hemolymph had spectrographic absorption maxima typical of the protein-free chromophore (phycoerythrobilin) and/or r-phycoerythrin, but only when the animal had been feeding on red algae. Rhodoplast digestive cells and their vacuoles were not induced by the type of food in the diet: snails fed green seaweed and animals fed lettuce had characteristic rhodoplast cells but without the large membranous inclusions (rhodoplasts) or phycobilisome-like granules found in animals fed red seaweed. Two additional cell types lining the tubules of the digestive gland were characterized ultrastructurally: (1) a club-shaped digestive cell filled with electron-dense material, and (2) a triangular 'secretory' cell devoid of storage material and calcium carbonate. The following model is consistent with our observations: red algal rhodoplasts are freed from algal cells in the foregut and then engulfed by rhodoplast digestive cells in the tubules of the digestive diverticula, where they are digested in membrane-bound vacuoles; r-phycoerythrin is released from phycobilisomes on the rhodoplast thylakoids and chemically modified before leaving the digestive vacuole and accumulating in the hemolymph; the pigment then circulates throughout the body and is concentrated in specialized cells and vesicles of the ink gland, where it is stored until secreted in response to certain predators.

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35

Seibert, M. "Reflections on the Nature and Function of the Photosystem II Reaction Centre". Functional Plant Biology 22, n.º 2 (1995): 161. http://dx.doi.org/10.1071/pp9950161.

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The reaction centre of photosystem II (PSII) converts light energy into chemical potential used by higher photosynthetic organisms to produce atmospheric oxygen. Water is the source of the oxygen and also the reductant required to fix atmospheric carbon dioxide. The purpose of this paper is to identify the physical location of the reaction centre complex in the thylakoid membrane, quantitate the core chlorophyll pigment stoichiometry in the isolated complex, discuss the primary charge-separation process, and examine current information on the nature of the primary electron donor of PSII.

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36

Gruber, J. Michael, Pavel Malý, Tjaart P. J. Krüger y Rienk van Grondelle. "From isolated light-harvesting complexes to the thylakoid membrane: a single-molecule perspective". Nanophotonics 7, n.º 1 (1 de enero de 2018): 81–92. http://dx.doi.org/10.1515/nanoph-2017-0014.

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AbstractThe conversion of solar radiation to chemical energy in plants and green algae takes place in the thylakoid membrane. This amphiphilic environment hosts a complex arrangement of light-harvesting pigment-protein complexes that absorb light and transfer the excitation energy to photochemically active reaction centers. This efficient light-harvesting capacity is moreover tightly regulated by a photoprotective mechanism called non-photochemical quenching to avoid the stress-induced destruction of the catalytic reaction center. In this review we provide an overview of single-molecule fluorescence measurements on plant light-harvesting complexes (LHCs) of varying sizes with the aim of bridging the gap between the smallest isolated complexes, which have been well-characterized, and the native photosystem. The smallest complexes contain only a small number (10–20) of interacting chlorophylls, while the native photosystem contains dozens of protein subunits and many hundreds of connected pigments. We discuss the functional significance of conformational dynamics, the lipid environment, and the structural arrangement of this fascinating nano-machinery. The described experimental results can be utilized to build mathematical-physical models in a bottom-up approach, which can then be tested on larger in vivo systems. The results also clearly showcase the general property of biological systems to utilize the same system properties for different purposes. In this case it is the regulated conformational flexibility that allows LHCs to switch between efficient light-harvesting and a photoprotective function.

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37

Popova, Antoaneta V., Preslava Borisova y Dimitar Vasilev. "Response of Pea Plants (Pisum sativum cv. Ran 1) to NaCl Treatment in Regard to Membrane Stability and Photosynthetic Activity". Plants 12, n.º 2 (10 de enero de 2023): 324. http://dx.doi.org/10.3390/plants12020324.

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Salinity is one of the most extreme abiotic stress factors that negatively affect the development and productivity of plants. The salt-induced injuries depend on the salt tolerance of the plant species, salt concentration, time of exposure and developmental stage. Here, we report on the response of pea plants (Pisum sativum L. cv Ran 1) to exposure to increasing salt concentrations (100, 150 and 200 mM NaCl) for a short time period (5 days) and the ability of the plants to recover after the removal of salt. The water content, membrane integrity, lipid peroxidation, pigment content and net photosynthetic rate were determined for the pea leaves of the control, treated and recovered plants. Salt-induced alterations in the primary photosynthetic reactions and energy transfer between the main pigment–protein complexes in isolated thylakoid membranes were evaluated. The pea plants were able to recover from the treatment with 100 mM NaCl, while at higher concentrations, concentration-dependent water loss, the disturbance of the membrane integrity, lipid peroxidation and an increase in the pigment content were detected. The net photosynthetic rate, electron transport through the reaction centers of PSII and PSII, activity of PSIIα centers and energy transfer between the pigment–protein complexes were negatively affected and were not restored after the removal of NaCl.

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38

Misra, Amarendra Narayan, Sachindra Mohan Sahu, Meena Misra, N. K. Ramaswamy y T. S. Desai. "Sodium Chloride Salt Stress Induced Changes in Thylakoid Pigment-Protein Complexes, Photosystem II Activity and Thermoluminescence Glow Peaks". Zeitschrift für Naturforschung C 54, n.º 9-10 (1 de octubre de 1999): 640–44. http://dx.doi.org/10.1515/znc-1999-9-1005.

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In the present study, mung bean (Vigna radiata L.) - a salt susceptible and Indian mustard (Brassica juncea L.) - a salt resistant crop was studied to find out the differences in stress responses of these crops. Seedlings were grown in water soaked cotton under continuous illumination of 35 μmole m-2 s-1 at 26 ± 1 °C. Salinity treatment of 0, 0.5 and 1.0% (w/v) was given to the seedlings at 6 day Photosynthetic pigment content and PS II electron transport activity was reduced under salinity in both mung bean and Indian mustard. The pigment protein pattern of both the crops were similar. Ratio analysis of B and Q thermoluminescence (TL) glow peaks suggested that S2QA- charge recombination was relatively more affected than S2/3QB- charge recombinations

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39

Krause, G. Heinrich y Henrik Laasch. "Energy-Dependent Chlorophyll Fluorescence Quenching in Chloroplasts Correlated with Quantum Yield of Photosynthesis". Zeitschrift für Naturforschung C 42, n.º 5 (1 de mayo de 1987): 581–84. http://dx.doi.org/10.1515/znc-1987-0514.

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Abstract Chlorophyll a fluorescence quenching was studied in intact, CO2 fixing chloroplasts isolated from spinach. Energy-dependent quenching (qᴇ), which is correlated with the light-induced pro ton gradient across the thylakoid membrane presumably reflects an increase in the rate-constant of thermal dissipation of excitation energy in the photosynthetic pigment system . The extent of qᴇ was found to be linearly related to the decrease of quantum yield of photosynthesis. We suggest that this relationship indicates a dynamic property of the membrane to adjust thermal dissipation of absorbed light energy to the energy requirement of photosynthesis.

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40

Collins, Aaron M., Michelle Liberton, Howland D. T. Jones, Omar F. Garcia, Himadri B. Pakrasi y Jerilyn A. Timlin. "Photosynthetic Pigment Localization and Thylakoid Membrane Morphology Are Altered in Synechocystis 6803 Phycobilisome Mutants". Plant Physiology 158, n.º 4 (13 de febrero de 2012): 1600–1609. http://dx.doi.org/10.1104/pp.111.192849.

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41

Bassi, Roberto. "A new function for the xanthophyll zeaxanthin: glueing chlorophyll biosynthesis to thylakoid protein assembly". Biochemical Journal 478, n.º 1 (8 de enero de 2021): 61–62. http://dx.doi.org/10.1042/bcj20200803.

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Xanthophylls are coloured isoprenoid metabolites synthesized in many organisms with a variety of functions from the attraction of animals for impollination to absorption of light energy for photosynthesis to photoprotection against photooxidative stress. The finding by Proctor and co-workers makes a new addition to the last type of functions by showing that zeaxanthin is instrumental in coordinating chlorophyll biosynthesis with the insertion of pigment-binding proteins into the photosynthetic membrane by glueing the protein components catalyzing these functions into a supercomplex and regulating its activity.

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42

Bergdahl, Roland, Christin Grundström, Patrik Storm, Wolfgang Schröder y Uwe Sauer. "Photosystem II assembly factor HCF136 from A. thaliana at 1.67 Å resolution". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 de agosto de 2014): C1170. http://dx.doi.org/10.1107/s2053273314088299.

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The High Chlorophyll Fluorescence 136 protein (HCF136) is essential for the assembly and repair of Photosystem II (PSII) and its central reaction centre (RC)[1]. HCF136 is an abundant protein in the thylakoid lumen and has been suggested to directly interact with subunits of the RC. The multi-subunit pigment-protein PSII complex is imbedded in the thylakoid membrane of the oxygenic photosynthetic organisms, and responsible for water splitting during oxygenic photosynthesis. PSII harbours more than 20 different integral and peripheral membrane proteins and its assembly requires a high level of coordination[2]. Two proteins D1 (psbA) and D2 (psbD) form the core of the complex and bind most of the redox-active co-factors. The PSII RC contains, in addition to D1 and D2, the intrinsic PsbI subunit and cytochrome b559. Light is a harmful substrate and subunits are damaged during the water-splitting reaction. The largest irreversible damage is experienced by the central D1 protein that has the highest turnover rate of all thylakoid proteins. Analysis of mutated A. thaliana has identified HCF136 as an essential factor for PSII RC assembly and RC turnover and repair[3]. In order to gain functional and structural insight in the way the HCF136 protein is involved in the PSII repair cycle, we have cloned, expressed, purified and crystallized the HCF136 protein from A. thaliana. Here we present the structure of this doughnut shaped WD40 domain family protein determined at 1.67 Å resolution. Biochemical and biophysical analysis of HCF136 and components of the PSII RC are under way.

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43

Pashayeva. "PsbS Dependence in Lipid and Pigment Composition in Rice Plants". Bulletin of Science and Practice 7, n.º 9 (15 de septiembre de 2021): 59–68. http://dx.doi.org/10.33619/2414-2948/70/05.

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Plants acclimate to fluctuations in light conditions by adjusting their photosynthetic apparatus. When the light intensity exceeds, an unbalanced excitation of the two photosystems occurs. It results in reduced photosynthetic efficiency. Photosystem II (PSII) is the most susceptible and dynamically regulated part of the light reactions in the thylakoid membrane. Non-photochemical quenching of chlorophyll fluorescence (NPQ) is one of the short-term photoprotective mechanisms, which consist of the number of components. The strongest NPQ component — qE is localized in the PSII antenna and induced in plants by lumen acidification, the activation of the pH sensor PsbS, and the conversion of the violaxanthin to zeaxanthin within the xanthophyll cycle. Here, I present data that characterizes the role of the PsbS protein in organization of PSII structural components in isolated PSII-enriched membranes. The preparations were isolated from wild-type (WT) and PsbS-less (PsbS-KO) mutant rice plant. Based on the obtained results, the PSII-enriched membranes from WT and PsbS-KO differ as in the level of lipids, also in carotenoids. I conclude that the PsbS-dependent changes in membrane fluidity in PsbS-KO mutant plants compensated with increased lipid level in mutant plants.

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Yue, Jianmin, Zhiyuan Fu, Liang Zhang, Zihan Zhang y Jinchi Zhang. "The Positive Effect of Different 24-epiBL Pretreatments on Salinity Tolerance in Robinia pseudoacacia L. Seedlings". Forests 10, n.º 1 (20 de diciembre de 2018): 4. http://dx.doi.org/10.3390/f10010004.

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As a brassinosteroid (BR), 24-epibrassinolide (24-epiBL) has been widely used to enhance the resistance of plants to multiple stresses, including salinity. Black locust (Robinia pseudoacacia L.) is a common species in degraded soils. In the current study, plants were pretreated with three levels of 24-epiBL (0.21, 0.62, or 1.04 µM) by either soaking seeds during the germination phase (Sew), foliar spraying (Spw), or root dipping (Diw) at the age of 6 months. The plants were exposed to salt stress (100 and 200 mM NaCl) via automatic drip-feeding (water content ~40%) for 45 days after each treatment. Increased salinity resulted in a decrease in net photosynthesis rate (Pn), stomatal conductance (Gs), intercellular:ambient CO2 concentration ratio (Ci/Ca), water-use efficiency (WUEi), and maximum quantum yield of photosystem II (PSII) (Fv/Fm). Non-photochemical quenching (NPQ) and thermal dissipation (Hd) were elevated under stress, which accompanied the reduction in the membrane steady index (MSI), water content (RWC), and pigment concentration (Chl a, Chl b, and Chl). Indicators of oxidative stress (i.e., malondialdehyde (MDA) and antioxidant enzymes (peroxidase (POD) and superoxide dismutase (SOD)) in leaves and Na+ content in chloroplasts increased accompanied by a reduction in chloroplastid K+ and Ca2+. At 200 mM NaCl, the chloroplast and thylakoid ultrastructures were severely disrupted. Exogenous 24-epiBL improved MSI, RWC, K+, and Ca2+ content, reduced Na+ levels, maintained chloroplast and thylakoid membrane structures, and enhanced the antioxidant ability in leaves. 24-epiBL also substantially alleviated stress-induced limitations of photosynthetic ability, reflected by elevated chlorophyll fluorescence, pigment levels, and Pn. The positive effects of alleviating salt stress in R. pseudoacacia seedlings in terms of treatment application was Diw > Sew > Spw, and the most positive impacts were seen with 1.04 µM 24-epiBL. These results provide diverse choice for 24-epiBL usage to defend against NaCl stress of a plant.

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45

Milivojevic, D. B. y B. R. Nikolic. "Effects of diquat on pigment-protein complexes of thylakoid membranes in soybean and maize plants". Biologia plantarum 41, n.º 4 (1 de mayo de 1998): 597–600. http://dx.doi.org/10.1023/a:1001804802959.

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Janik, Ewa, Waldemar Maksymiec, Wojciech Grudziński y Wiesław I. Gruszecki. "Strong light-induced reorganization of pigment–protein complexes of thylakoid membranes in rye (spectroscopic study)". Journal of Plant Physiology 169, n.º 1 (enero de 2012): 65–71. http://dx.doi.org/10.1016/j.jplph.2011.08.021.

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Rhiel, E., E. M�rschel y W. Wehrmeyer. "Correlation of pigment deprivation and ultrastructural organization of thylakoid membranes incryptomonas maculata following nutrient deficiency". Protoplasma 129, n.º 1 (febrero de 1985): 62–73. http://dx.doi.org/10.1007/bf01282306.

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Karlicky, V., J. Podolinska, L. Nadkanska, M. Stroch, M. Cajanek y V. Spunda. "Pigment composition and functional state of the thylakoid membranes during preparation of samples for pigment-protein complexes separation by nondenaturing gel electrophoresis". Photosynthetica 48, n.º 3 (1 de septiembre de 2010): 475–80. http://dx.doi.org/10.1007/s11099-010-0063-y.

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Wójtowicz, Joanna y Katarzyna B. Gieczewska. "The Arabidopsis Accessions Selection Is Crucial: Insight from Photosynthetic Studies". International Journal of Molecular Sciences 22, n.º 18 (13 de septiembre de 2021): 9866. http://dx.doi.org/10.3390/ijms22189866.

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Natural genetic variation in photosynthesis is strictly associated with the remarkable adaptive plasticity observed amongst Arabidopsis thaliana accessions derived from environmentally distinct regions. Exploration of the characteristic features of the photosynthetic machinery could reveal the regulatory mechanisms underlying those traits. In this study, we performed a detailed characterisation and comparison of photosynthesis performance and spectral properties of the photosynthetic apparatus in the following selected Arabidopsis thaliana accessions commonly used in laboratories as background lines: Col-0, Col-1, Col-2, Col-8, Ler-0, and Ws-2. The main focus was to distinguish the characteristic disparities for every accession in photosynthetic efficiency that could be accountable for their remarkable plasticity to adapt. The biophysical and biochemical analysis of the thylakoid membranes in control conditions revealed differences in lipid-to-protein contribution, Chlorophyll-to-Carotenoid ratio (Chl/Car), and xanthophyll cycle pigment distribution among accessions. We presented that such changes led to disparities in the arrangement of the Chlorophyll-Protein complexes, the PSI/PSII ratio, and the lateral mobility of the thylakoid membrane, with the most significant aberrations detected in the Ler-0 and Ws-2 accessions. We concluded that selecting an accession suitable for specific research on the photosynthetic process is essential for optimising the experiment.

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Romanowska, Elzbieta y Anna Drozak. "Comparative analysis of biochemical properties of mesophyll and bundle sheath chloroplasts from various subtypes of C4 plants grown at moderate irradiance." Acta Biochimica Polonica 53, n.º 4 (14 de noviembre de 2006): 709–19. http://dx.doi.org/10.18388/abp.2006_3298.

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The photochemical characteristics of mesophyll and bundle sheath chloroplasts isolated from the leaves of C4 species were investigated in Zea mays (NADP-ME type), Panicum miliaceum (NAD-ME type) and Panicum maximum (PEP-CK type) plants. The aim of this work was to gain information about selected photochemical properties of mesophyll and bundle sheath chloroplasts isolated from C4 plants grown in the same moderate light conditions. Enzymatic as well as mechanical methods were applied for the isolation of bundle sheath chloroplasts. In the case of Z. mays and P. maximum the enzymatic isolation resulted in the loss of some thylakoid polypeptides. It was found that the PSI and PSII activities of mesophyll and bundle sheath chloroplasts of all species studied differed significantly and the differences correlated with the composition of pigment-protein complexes, photophosphorylation efficiency and fluorescence emission characteristic of these chloroplasts. This is the first report showing differences in the photochemical activities between mesophyll chloroplasts of C4 subtypes. Our results also demonstrate that mesophyll and bundle sheath chloroplasts of C4 plants grown in identical light conditions differ significantly with respect to the activity of main thylakoid complexes, suggesting a role of factor(s) other than light in the development of photochemical activity in C4 subtypes.

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