Dynamic quenching in single photosystem II supercomplexes

2016 ◽  
Vol 18 (37) ◽  
pp. 25852-25860 ◽  
Author(s):  
J. Michael Gruber ◽  
Pengqi Xu ◽  
Jevgenij Chmeliov ◽  
Tjaart P. J. Krüger ◽  
Maxime T. A. Alexandre ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Photochemical Quenching ◽  
Dynamic Quenching ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Fluorescence Measurements ◽  
Non Photochemical Quenching

Time-resolved fluorescence measurements of single PSII supercomplexes to investigate blinking and dynamic quenching in the context of non-photochemical quenching (NPQ).

Fluorescence property of photosystem II protein complexes bound to a gold nanoparticle

2017 ◽  
Vol 198 ◽  
pp. 121-134 ◽  
Author(s):  
Kazuki Tahara ◽  
Ahmed Mohamed ◽  
Kousuke Kawahara ◽  
Ryo Nagao ◽  
Yuki Kato ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Gold Nanoparticle ◽  
Water Oxidation ◽  
Artificial Photosynthesis ◽  
Fluorescence Property ◽  
Light Illumination ◽  
Time Resolved Fluorescence ◽  
Strong Light ◽  
Time Resolved ◽  
Fluorescence Measurements

Development of an efficient photo-anode system for water oxidation is key to the success of artificial photosynthesis. We previously assembled photosystem II (PSII) proteins, which are an efficient natural photocatalyst for water oxidation, on a gold nanoparticle (GNP) to prepare a PSII–GNP conjugate as an anode system in a light-driven water-splitting nano-device (Noji et al., J. Phys. Chem. Lett., 2011, 2, 2448–2452). In the current study, we characterized the fluorescence property of the PSII–GNP conjugate by static and time-resolved fluorescence measurements, and compared with that of free PSII proteins. It was shown that in a static fluorescence spectrum measured at 77 K, the amplitude of a major peak at 683 nm was significantly reduced and a red shoulder at 693 nm disappeared in PSII–GNP. Time-resolved fluorescence measurements showed that picosecond components at 683 nm decayed faster by factors of 1.4–2.1 in PSII–GNP than in free PSII, explaining the observed quenching of the major fluorescence peak. In addition, a nanosecond-decay component arising from a ‘red chlorophyll’ at 693 nm was lost in time-resolved fluorescence of PSII–GNP, probably due to a structural perturbation of this chlorophyll by interaction with GNP. Consistently with these fluorescence properties, degradation of PSII during strong-light illumination was two times slower in PSII–GNP than in free PSII. The enhanced durability of PSII is an advantageous property of the PSII–GNP conjugate in the development of an artificial photosynthesis device.

Time-Resolved Fluorescence Measurements of Photosystem II:  The Effect of Quenching by Oxidized Chlorophyll Z

1998 ◽  
Vol 102 (42) ◽  
pp. 8320-8326 ◽  
Author(s):  
Robert H. Schweitzer ◽  
Alexander N. Melkozernov ◽  
Robert E. Blankenship ◽  
Gary W. Brudvig
Keyword(s):  
Photosystem Ii ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Fluorescence Measurements

scholarly journals The quantitative contribution of different Photosystem II compartments to non-photochemical quenching in Arabidopsis

2021 ◽  
Author(s):  
Lauren Nicol ◽  
Vincenzo Mascoli ◽  
Herbert van Amerongen ◽  
Roberta Croce
Keyword(s):  
Photosystem Ii ◽  
Excitation Energy ◽  
Quantitative Description ◽  
Photosynthetic Apparatus ◽  
Intrinsic Rate ◽  
High Light Intensity ◽  
Photochemical Quenching ◽  
Irreversible Damage ◽  
Fluorescence Measurements ◽  
Non Photochemical Quenching

Excess excitation energy in the light-harvesting antenna of Photosystem II (PSII) can cause irreversible damage to the photosynthetic apparatus. In periods of high light intensity, a feedback mechanism known as non-photochemical quenching (NPQ), induces the formation of quenchers which can safely dissipate excess excitation energy as heat. Although quenchers have been identified in more than one compartment of the PSII supercomplex, there is currently no quantitative description of how much NPQ is occurring at each of these locations. Here, we perform time-resolved fluorescence measurements on WT and antenna mutants lacking LHCII (NoL) and all peripheral antenna (Ch1 and Ch1lhcb5). By combining the results with those of steady-state fluorescence experiments we are able to estimate the intrinsic rate of NPQ for each plant and each PSII compartment. It is concluded that 60-70% of quenching occurs in LHCII, 15-20% in the minor antenna and 15-20% in the PSII core.

scholarly journals Ground and excited-state interactions of coumarin and nucleotide base

1988 ◽  
Vol 66 (3) ◽  
pp. 513-516 ◽  
Author(s):  
Grażyna Wenska ◽  
Stefan Paszyc
Keyword(s):  
Organic Solvents ◽  
Relative Proportion ◽  
Stacking Interactions ◽  
Dynamic Quenching ◽  
Time Resolved Fluorescence ◽  
Quenching Mechanism ◽  
Time Resolved ◽  
Nucleotide Base ◽  
Fluorescence Measurements ◽  
Total Fluorescence

Steady-state and time-resolved fluorescence measurements for a series of bichromophoric compounds containing 7-methoxy-coumarin and nucleotide base residues have been performed in water and in organic solvents. The data from these studies have been used to calculate the relative proportion of folded and extended conformations of bichromophores. Ground-state stacking interactions of coumarin and nucleotide base have been found to be limited to aqueous solution. The contribution of the dynamic quenching mechanism to the total fluorescence quenching in water has been estimated. The absence of dynamic quenching in organic solvents is.explained on the basis of the very short lifetime of the fluorophore in methanol.

Light Absorption and Partitioning in Response to Nitrogen in Apple Leaves

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541a-541
Author(s):  
Lailiang Cheng ◽  
Leslie H. Fuchigami ◽  
Patrick J. Breen
Keyword(s):  
High Light ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Psii Efficiency ◽  
Fluorescence Measurements ◽  
Free Radical Formation ◽  
Highly Correlated ◽  
Non Photochemical Quenching ◽  
Leaf N

Bench-grafted Fuji/M26 apple trees were fertigated with different concentrations of nitrogen by using a modified Hoagland solution for 6 weeks, resulting in a range of leaf N from 1.0 to 4.3 g·m–2. Over this range, leaf absorptance increased curvilinearly from 75% to 92.5%. Under high light conditions (1500 (mol·m–2·s–1), the amount of absorbed light in excess of that required to saturate CO2 assimilation decreased with increasing leaf N. Chlorophyll fluorescence measurements revealed that the maximum photosystem II (PSII) efficiency of dark-adapted leaves was relatively constant over the leaf N range except for a slight drop at the lower end. As leaf N increased, non-photochemical quenching under high light declined and there was a corresponding increase in the efficiency with which the absorbed photons were delivered to open PSII centers. Photochemical quenching coefficient decreased significantly at the lower end of the leaf N range. Actual PSII efficiency increased curvilinearly with increasing leaf N, and was highly correlated with light-saturated CO2 assimilation. The fraction of absorbed light potentially used for free radical formation was estimated to be about 10% regardless of the leaf N status. It was concluded that increased thermal dissipation protected leaves from photo-oxidation as leaf N declined.

scholarly journals Growth under Fluctuating Light Reveals Large Trait Variation in a Panel of Arabidopsis Accessions

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 316 ◽  
Author(s):  
Elias Kaiser ◽  
Dirk Walther ◽  
Ute Armbruster
Keyword(s):  
Photosystem Ii ◽  
Chemical Potential ◽  
Genomic Variation ◽  
Operating Efficiency ◽  
Photochemical Quenching ◽  
Low Light ◽  
Trait Variation ◽  
Light Regimes ◽  
Fluctuating Light ◽  
Non Photochemical Quenching

The capacity of photoautotrophs to fix carbon depends on the efficiency of the conversion of light energy into chemical potential by photosynthesis. In nature, light input into photosynthesis can change very rapidly and dramatically. To analyze how genetic variation in Arabidopsis thaliana affects photosynthesis and growth under dynamic light conditions, 36 randomly chosen natural accessions were grown under uniform and fluctuating light intensities. After 14 days of growth under uniform or fluctuating light regimes, maximum photosystem II quantum efficiency (Fv/Fm) was determined, photosystem II operating efficiency (ΦPSII) and non-photochemical quenching (NPQ) were measured in low light, and projected leaf area (PLA) as well as the number of visible leaves were estimated. Our data show that ΦPSII and PLA were decreased and NPQ was increased, while Fv/Fm and number of visible leaves were unaffected, in most accessions grown under fluctuating compared to uniform light. There were large changes between accessions for most of these parameters, which, however, were not correlated with genomic variation. Fast growing accessions under uniform light showed the largest growth reductions under fluctuating light, which correlated strongly with a reduction in ΦPSII, suggesting that, under fluctuating light, photosynthesis controls growth and not vice versa.

Sensitive, rapid procedure for time-resolved immunofluorometry of lutropin.

1988 ◽  
Vol 34 (8) ◽  
pp. 1640-1644 ◽  
Author(s):  
M J Khosravi ◽  
R C Morton ◽  
E P Diamandis
Keyword(s):  
Monoclonal Antibody ◽  
Solid Phase ◽  
Detection System ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Practical Procedure ◽  
Daily Monitoring ◽  
Fluorescence Measurements ◽  
Capture Antibody ◽  
Europium Chelate

Abstract In this new immunofluorometric method for quantification of lutropin in serum, the "sandwich" principle is combined with time-resolved fluorescence measurements, with the europium chelate 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA) used as label. A monoclonal antibody to the alpha-subunit of lutropin is adsorbed onto the walls of white-opaque microtiter wells to form the solid-phase capture antibody, and a biotin-labeled soluble monoclonal antibody is used for antigen quantification. The detection system is completed with streptavidin, which has been linked to a protein bulking agent labeled with multiple BCPDA residues. In the presence of excess europium, the fluorescence of the final complex attached to captured lutropin molecules is measured on the dried solid phasse with an automated time-resolved fluorometer. The assay can be performed as a rapid (less than 60 min incubation) or regular (150 min incubation) procedure. The rapid assay is well-suited for routine daily monitoring of increasing or ovulatory lutropin concentrations; the regular assay, with its greater sensitivity (0.5 int. unit/L), is a practical procedure for lutropin measurements in hyposecretory states. The assay measures up to 240 int. units/L, and results compare well with those by a commercially available radioimmunoassay, an immunoradiometric assay, and another time-resolved immunofluorometric procedure.

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