scholarly journals Light Induced Changes in Pigment and Lipid Profiles of Bryopsidales Algae

2021 ◽  
Vol 8 ◽  
Author(s):  
Chiara E. Giossi ◽  
Sónia Cruz ◽  
Felisa Rey ◽  
Rúben Marques ◽  
Tânia Melo ◽  
...  

Bryopsidales (Chlorophyta) are cultured and consumed in several regions of the planet and are known for their high nutritional value and bioprospection potential, due to a high content of relevant polar lipids and polysaccharides. Among other characteristic features, these marine algae are known for possessing unique photosynthetic pigment-protein complexes and for the absence (in nearly all species investigated) of a functional xanthophyll cycle, a ubiquitous photoprotection mechanism present in most algae and plants. With the aim of characterizing the photophysiology of this atypical group of algae, we investigated the changes in pigment content and polar lipidome of two Bryopsidales species (Codium tomentosum and Bryopsis plumosa) exposed for 7 days to low or high irradiance (20 vs. 1,000 μmol photons m–2 s–1). Our results show that high light has a strong effect on the pigment composition, triggering the time-dependent accumulation of all-trans-neoxanthin (t-Neo) and violaxanthin (Viola). High light-acclimated macroalgae also displayed a shift in the characteristic polar lipidome, including a trend of accumulation of lyso-glycolipids, and highly unsaturated phospholipids and betaine lipids. We hypothesize that the observed shifts on the lipid composition could promote the interaction between t-Neo and Viola with the siphonaxanthin–chlorophyll–protein complexes (SCP) of photosystem II (PSII) within the thylakoid membranes of the chloroplasts. Light induced changes in pigment and lipid composition could contribute to the fitness of Bryopsidales algae by reducing damages to the photosynthetic apparatus under increased irradiance.

2021 ◽  
Vol 22 (18) ◽  
pp. 9866
Author(s):  
Joanna Wójtowicz ◽  
Katarzyna B. Gieczewska

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.


1993 ◽  
Author(s):  
Rachel Nechushtai ◽  
Parag Chitnis

The major goal of the proposed research was to study the role of a 70-kDa heat shock cognate protein from chloroplasts (ct-HSP70) in the assembly of chlorophyll-protein complexes. The latters are mostly important in allowing photosynthesis to occur. Photosynthesis is at the heart of crop productivity and the knowledge of the biogenesis of the photosynthetic apparatus is essential to manipulate the efficiency of photosynthesis. The characterization of the function of the ct-HSP70 was planned to be studied in vitro by assaying its capability to physically interact with the thylakoid proteins and to assist their assembly into thylakoid membranes. We planned to identify regions in the light-harvesting complex protein (LHCP) that interact with the ct-HSP70 and characterize the interaction between them. We also intended to isolate cDNA clones encoding ct-HSP70, sequence them, express one of them in E. coli and use the purified protein for functional assays. The research in this BARD proposal aimed at providing insights and aid in understanding the mechanism by which plants may respond to the heat stress. Since plants often experience increased temperatures.


Author(s):  
Thomas S. Bianchi ◽  
Elizabeth A. Canuel

This chapter examines the primary photosynthetic pigments used in absorbing photosynthetically active radiation, which include chlorophylls, carotenoids, and phycobilins—with chlorophyll representing the dominant photosynthetic pigment. Although a greater amount of chlorophyll is found on land, 75% of the annual global turnover occurs in oceans, lakes, and rivers/estuaries. All of the light-harvesting pigments are bound to proteins making up distinct carotenoid and chlorophyll-protein complexes. The chapter considers the chemistry and application of these very important chemical biomarkers and discusses their limitations in aquatic systems. The matrix factorization program CHEMical TAXonomy (CHEMTAX) was introduced to calculate the relative abundance of major algal groups based on concentrations of diagnostic pigments and is also discussed.


1997 ◽  
Vol 24 (2) ◽  
pp. 205 ◽  
Author(s):  
Ralph A. Bungard ◽  
David McNeil ◽  
James D. Morton

Effects of nitrogen supply (N-supply) on the photosynthetic apparatus of Clematis vitalba L. grown at several irradiances were determined by measuring soluble protein content, rubisco activity, photosynthetic pigment content and composition, and the photochemical efficiency of photosystem II (Fv/Fm). Compared to low irradiance (3 and 10% full sunlight), leaves grown at higher irradiance (up to full sunlight) had up to 5–6 times the soluble protein content and rubisco activity, and up to 2–4 times the total carotenoid content, on both a leaf area and a chlorophyll basis. On a leaf area basis, decreased N-supply reduced soluble protein concentration, rubisco activity and total carotenoid concentration to a greater extent at high compared to low irradiance. On a chlorophyll basis, in contrast, soluble protein and rubisco activity decreased by over 40% with increased N-supply (1.0–0.1 mol m-3) at high irradiance but N-supply did not influence the concentration of total carotenoids. Leaves grown at high compared to low irradiance had a greater concentration of xanthophyll cycle pigments (V+A+Z), β-carotene and lutein (but not neoxanthin) on a chlorophyll basis, and a slightly lower Fv/Fm. Nitrogen- supply did not influence the composition of the photosynthetic pigment pool, Fv/Fm, or the extent of de-epoxidation of the V+A+Z pool. The results suggest that irradiance-acclimation of C. vitalba can occur regardless of N-supply. Under N limitation at high irradiance, a balance between light capture and photosynthetic capacity is important rather than an increase in xanthophyll cycle-dependent energy dissipation. The importance of lutein as a light-harvesting pigment is questioned. A rapid method for the reversed phase-HPLC separation of carotenoids is described.


2000 ◽  
Vol 182 (19) ◽  
pp. 5440-5447 ◽  
Author(s):  
Muktak Aklujkar ◽  
Andrea L. Harmer ◽  
Roger C. Prince ◽  
J. Thomas Beatty

ABSTRACT The orf162b sequence, the second open reading frame 3′ of the reaction center (RC) H protein gene puhA in theRhodobacter capsulatus photosynthesis gene cluster, is shown to be transcribed from a promoter located 5′ of puhA. A nonpolar mutation of orf162b was generated by replacing most of the coding region with an antibiotic resistance cartridge. Although the mutant strain initiated rapid photosynthetic growth, growth slowed progressively and cultures often entered a pseudostationary phase. The amounts of the RC and light harvesting complex I (LHI) in cells obtained from such photosynthetic cultures were abnormally low, but these deficiencies were less severe when the mutant was grown to a pseudostationary phase induced by low aeration in the absence of illumination. The orf162b mutation did not significantly affect the expression of apufB::lacZ translationally in-frame gene fusion under the control of the puf promoter, indicating normal transcription and translation of RC and LHI genes. Spontaneous secondary mutations in the strain with theorf162b disruption resulted in a bypass of the photosynthetic growth retardation and reduced the level of light harvesting complex II. These results and the presence of sequences similar to orf162b in other species indicate that the Orf162b protein is required for normal levels of the photosynthetic apparatus in purple photosynthetic bacteria.


1992 ◽  
Vol 119 (2) ◽  
pp. 325-335 ◽  
Author(s):  
R Barbato ◽  
G Friso ◽  
F Rigoni ◽  
F Dalla Vecchia ◽  
G M Giacometti

The structural and topological stability of thylakoid components under photoinhibitory conditions (4,500 microE.m-2.s-1 white light) was studied on Mn depleted thylakoids isolated from spinach leaves. After various exposures to photoinhibitory light, the chlorophyll-protein complexes of both photosystems I and II were separated by sucrose gradient centrifugation and analysed by Western blotting, using a set of polyclonals raised against various apoproteins of the photosynthetic apparatus. A series of events occurring during donor side photoinhibition are described for photosystem II, including: (a) lowering of the oligomerization state of the photosystem II core; (b) cleavage of 32-kD protein D1 at specific sites; (c) dissociation of chlorophyll-protein CP43 from the photosystem II core; and (d) migration of damaged photosystem II components from the grana to the stroma lamellae. A tentative scheme for the succession of these events is illustrated. Some effects of photoinhibition on photosystem I are also reported involving dissociation of antenna chlorophyll-proteins LHCI from the photosystem I reaction center.


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