scholarly journals Novel chlorophylls and new directions in photosynthesis research

2015 ◽  
Vol 42 (6) ◽  
pp. 493 ◽  
Author(s):  
Yaqiong Li ◽  
Min Chen
Keyword(s):  
Chlorophyll A ◽  
Red Light ◽  
Oxygenic Photosynthesis ◽  
Ecological Niches ◽  
Absorption Bands ◽  
Absorption Region ◽  
Chlorophyll D ◽  
And Function ◽  
Unique Status ◽  
Chlorophyll F

Chlorophyll d and chlorophyll f are red-shifted chlorophylls, because their Qy absorption bands are significantly red-shifted compared with chlorophyll a. The red-shifted chlorophylls broaden the light absorption region further into far red light. The presence of red-shifted chlorophylls in photosynthetic systems has opened up new possibilities of research on photosystem energetics and challenged the unique status of chlorophyll a in oxygenic photosynthesis. In this review, we report on the chemistry and function of red-shifted chlorophylls in photosynthesis and summarise the unique adaptations that have allowed the proliferation of chlorophyll d- and chlorophyll f-containing organisms in diverse ecological niches around the world.

Photochemistry beyond the red limit in chlorophyll f–containing photosystems

Science ◽  
2018 ◽  
Vol 360 (6394) ◽  
pp. 1210-1213 ◽  
Author(s):  
Dennis J. Nürnberg ◽  
Jennifer Morton ◽  
Stefano Santabarbara ◽  
Alison Telfer ◽  
Pierre Joliot ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Charge Separation ◽  
Red Light ◽  
Oxygenic Photosynthesis ◽  
Long Wavelength ◽  
Photosystems I And Ii ◽  
Biophysical Studies ◽  
A Charge ◽  
Photosystem I And Ii ◽  
Chlorophyll F

Photosystems I and II convert solar energy into the chemical energy that powers life. Chlorophyll a photochemistry, using red light (680 to 700 nm), is near universal and is considered to define the energy “red limit” of oxygenic photosynthesis. We present biophysical studies on the photosystems from a cyanobacterium grown in far-red light (750 nm). The few long-wavelength chlorophylls present are well resolved from each other and from the majority pigment, chlorophyll a. Charge separation in photosystem I and II uses chlorophyll f at 745 nm and chlorophyll f (or d) at 727 nm, respectively. Each photosystem has a few even longer-wavelength chlorophylls f that collect light and pass excitation energy uphill to the photochemically active pigments. These photosystems function beyond the red limit using far-red pigments in only a few key positions.

ANALYSE DER PHOTOSYNTHESE MIT BLITZLICHT

1964 ◽  
Vol 19 (8) ◽  
pp. 693-707 ◽  
Author(s):  
B. Rumberg ◽  
H. T. Witt
Keyword(s):  
Chlorophyll A ◽  
Red Light ◽  
Difference Spectrum ◽  
Reaction Scheme ◽  
Back Reaction ◽  
Absorption Bands ◽  
Light Reaction ◽  
Background Light ◽  
Light Product ◽  
The Difference

The primary reactions of photosynthesis are fast reactions. To get detailed informations we developed three different methods. 1. sensitive flash photometry 38, 2. periodically chemical relaxation51, 26a, 3. manometry in flashing light groups 26b. With the method of flash photometry fast absorption changes in suspensions of chlorella and spinach chloroplasts were studied. 7 different types of absorption changes have been separated and analysed (Fig. 2). Older results 28-49lead to a reaction scheme published in l. c. 13. This scheme was refined (s. Fig. 3) by results published in l. c. 14-26. In the following 6 papers these investigations are described in detail and supplement by new results.Separation of the difference-spectrum of chlorophyll-al (P 700) in 5 ways. Under “normal” conditions (exciting Hill - active chloroplasts with blue light between 380 and 480 mμ or with red light between 620 and 720 mµ) mixed changes of absorption can be observed between 400 and 800 mµ (Fig. 4, this difference-spectrum does not include the changes with τ<10-3 sec, s. Fig. 2). Out of this overall difference-spectrum one component with changes of absorption at 430 and 703 mμ could be separated by using the following different systems: a) aged chloroplasts reactivated by addition of reduced DPIP or reduced PMS (ascorbate in excess) (Fig. 5), b) plastoquinone-extracted chloroplasts [extraction with petroleumether] (Fig. 6), c) digitonin-treated chloroplasts reactivated by addition of reduced PMS [ascorbate in excess] (Fig. 7), d) chloroplasts at -150°C with addition of reduced PMS [ascorbate in excess] (Fig. 8), e) chloroplasts under the influence of far-red background-light [728 mµ] (Fig. 9).Kinetics. During the flash the absorption at 430 and 703 mµ decreases very fast (<10-5 sec). In the dark the back reaction takes place in ≈10-2 sec at 20°C (s. Fig. 10). This reaction time is always observable in the presents of far redbackground light λ>700 mμ. (The detecting light at 703 mµ can act already as far red background light.) At very low itensities of far red background light the backreaction takes place however in <10-4 sec (details s. l. c. 25a).Identification of chlorophyll-al. The upper results (5 equal spectra under different conditions) suggest that the changes of absorption at 430 and 703 mμ are caused by one substance. This was additionally proved by comparing the magnitude and the kinetic of both changes in reactivated aged or digitonin-treated chloroplasts under different conditions. The ratio of the amplitudes and the halflifes are identical at 430 and 703 mµ at different values of pH (Fig. 11 and Fig. 12) and also at different concentrations of added reduced PMS (Fig. 13). Decreases of absorption just within the two absorption bands of chlorophyll-a indicate that very probably a chlorophyll-a (Chl-aI-430-703) is in action. From the magnitude of the changes of absorption at 703 mμ it follows, that Chl-al has a concentration of 0,1% of the bulk of chlorophyll.Oxidation of Chl-ai. The decreases of absorption indicate an oxidation of Chl-al in the light. This is proved by the fact, that in aged or digitonin-treated chloroplasts reduced PMS can be directly coupled to the light product. This is demonstrated by the strong acceleration of the back reaction with increasing concentrations of reduced PMS (Fig. 13 and Fig. 15) and by the demonstration of a first order back reaction (Fig. 14 and Fig. 15). The experimental results are theoretically explained. It is proved, that the light product Chl-aI⨁ reacts with PMSH⊖ [compare measuring points and theoretical curve in Fig. 12] [s. scheme (1)]. From the measurements it follows a reaction constant of 1,5·107 l/Mol·sec (Fig. 15) and an energy of activation of 3,8 kcal/Mol (Fig. 16) for the reaction of Chl-aI⨁ with PMSH⊖.Chl-aI-oxidation as a primary act. The fact, that Chl-ai⊕ is built up within <10-5 sec (20°C) [Fig. 10] and that Chl-aI⨂ could be trapped at -150°C (Fig. 8 and Fig. 17) give evidence, that this oxidation is a primary act. The electron acceptor of Chl-ai is called Ζ. Ζ⊖ reduces via intermediary products TPN. Under the reported conditions a - e one light reaction cycle (I) of the overall electron transport system of photosynthesis has been isolated [s. scheme (1) and (2)].

scholarly journals The structure of Photosystem I acclimated to far-red light illuminates an ecologically important acclimation process in photosynthesis

2020 ◽  
Vol 6 (6) ◽  
pp. eaay6415 ◽  
Author(s):  
Christopher Gisriel ◽  
Gaozhong Shen ◽  
Vasily Kurashov ◽  
Ming-Yang Ho ◽  
Shangji Zhang ◽  
...  
Keyword(s):  
Photosystem I ◽  
Binding Sites ◽  
Structural Changes ◽  
Red Light ◽  
Oxygenic Photosynthesis ◽  
Cryo Electron Microscopy ◽  
Photosynthetic Proteins ◽  
Functional Differences ◽  
Light Utilization ◽  
Chlorophyll F

Phototrophic organisms are superbly adapted to different light environments but often must acclimate to challenging competition for visible light wavelengths in their niches. Some cyanobacteria overcome this challenge by expressing paralogous photosynthetic proteins and by synthesizing and incorporating ~8% chlorophyll f into their Photosystem I (PSI) complexes, enabling them to grow under far-red light (FRL). We solved the structure of FRL-acclimated PSI from the cyanobacterium Fischerella thermalis PCC 7521 by single-particle, cryo–electron microscopy to understand its structural and functional differences. Four binding sites occupied by chlorophyll f are proposed. Subtle structural changes enable FRL-adapted PSI to extend light utilization for oxygenic photosynthesis to nearly 800 nm. This structure provides a platform for understanding FRL-driven photosynthesis and illustrates the robustness of adaptive and acclimation mechanisms in nature.

scholarly journals Antioxidant and Signaling Role of Plastid-Derived Isoprenoid Quinones and Chromanols

2021 ◽  
Vol 22 (6) ◽  
pp. 2950
Author(s):  
Beatrycze Nowicka ◽  
Agnieszka Trela-Makowej ◽  
Dariusz Latowski ◽  
Kazimierz Strzalka ◽  
Renata Szymańska
Keyword(s):  
Current Knowledge ◽  
Stress Factors ◽  
Oxygenic Photosynthesis ◽  
Ros Generation ◽  
Main Site ◽  
Storage Lipids ◽  
Abiotic Stress Factors ◽  
Cell Components ◽  
And Function

Plant prenyllipids, especially isoprenoid chromanols and quinols, are very efficient low-molecular-weight lipophilic antioxidants, protecting membranes and storage lipids from reactive oxygen species (ROS). ROS are byproducts of aerobic metabolism that can damage cell components, they are also known to play a role in signaling. Plants are particularly prone to oxidative damage because oxygenic photosynthesis results in O2 formation in their green tissues. In addition, the photosynthetic electron transfer chain is an important source of ROS. Therefore, chloroplasts are the main site of ROS generation in plant cells during the light reactions of photosynthesis, and plastidic antioxidants are crucial to prevent oxidative stress, which occurs when plants are exposed to various types of stress factors, both biotic and abiotic. The increase in antioxidant content during stress acclimation is a common phenomenon. In the present review, we describe the mechanisms of ROS (singlet oxygen, superoxide, hydrogen peroxide and hydroxyl radical) production in chloroplasts in general and during exposure to abiotic stress factors, such as high light, low temperature, drought and salinity. We highlight the dual role of their presence: negative (i.e., lipid peroxidation, pigment and protein oxidation) and positive (i.e., contribution in redox-based physiological processes). Then we provide a summary of current knowledge concerning plastidic prenyllipid antioxidants belonging to isoprenoid chromanols and quinols, as well as their structure, occurrence, biosynthesis and function both in ROS detoxification and signaling.

scholarly journals Harvesting Far-Red Light with Plant Antenna Complexes Incorporating Chlorophyll d

2021 ◽  
Author(s):  
Eduard Elias ◽  
Nicoletta Liguori ◽  
Yoshitaka Saga ◽  
Judith Schäfers ◽  
Roberta Croce
Keyword(s):  
Red Light ◽  
Chlorophyll D

Chlorophyll f can replace chlorophyll a in the soluble antenna of dinoflagellates

2022 ◽  
Author(s):  
Miguel A. Hernández‐Prieto ◽  
Roger Hiller ◽  
Min Chen
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll F

scholarly journals A photosystem I reaction center driven by chlorophyll d in oxygenic photosynthesis

1998 ◽  
Vol 95 (22) ◽  
pp. 13319-13323 ◽  
Author(s):  
Q. Hu ◽  
H. Miyashita ◽  
I. Iwasaki ◽  
N. Kurano ◽  
S. Miyachi ◽  
...  
Keyword(s):  
Reaction Center ◽  
Photosystem I ◽  
Oxygenic Photosynthesis ◽  
Chlorophyll D

scholarly journals Chlorophyll a fluorescence as an indicator of water stress in Calophyllum brasiliense

2020 ◽  
Vol 48 (1) ◽  
pp. 210-220 ◽  
Author(s):  
Lucas C. REIS ◽  
Silvana P.Q. SCALON ◽  
Daiane DRESCH ◽  
Andressa Caroline FORESTI ◽  
Cleberton C. SANTOS ◽  
...  
Keyword(s):  
Water Deficit ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Stress Condition ◽  
Water Status ◽  
Photosynthetic Apparatus ◽  
Stress Indicator ◽  
Fluorescence Measurements ◽  
Calophyllum Brasiliense ◽  
And Function

The objective of this study was to evaluate chlorophyll a fluorescence as a stress indicator in Calophyllum brasiliense Cambess seedlings grown with different concentrations of abscisic acid (ABA) under intermittent water deficit condition: daily irrigation without ABA (I); daily irrigation + 10 μM ABA (I 10); daily irrigation + 100 μM ABA (I 100); suspension of daily irrigation without ABA (SI); suspension of daily irrigation + 10 μM ABA (SI 10) and  suspension of daily irrigation + 100 μM ABA (SI 100). The intermittent water deficit reduces water status and impairs the photochemical apparatus functioning and seedling quality. The fluorescence measurements helped identify the stress condition of water deficit in the cultivation of C. brasiliense and the beneficial effect of the application of 10 μM of ABA in minimizing stress and facilitating the recovery of seedlings after re-irrigation, while maintaining the integrity and function of the photosynthetic apparatus.

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