Photosynthetic light reactions

‘Candidatus Phytoplasma solani’ is endemic in Europe and infects a wide range of weeds and cultivated plants. Phytoplasmas are prokaryotic plant pathogens that colonize the sieve elements of their host plant, causing severe alterations in phloem function and impairment of assimilate translocation.

21p visilicon2711 20-08-2021 15 1   Download

Photosynthesis is able to convert solar energy into chemical energy in the form of biomass, but the efficiency of photosynthetic solar energy conversion is low. Chlorophyll fluorescence measurements are rapid, nondestructive, and can provide a wealth of information about the efficiencies of the photosynthetic light reaction processes.

19p vishikamaru2711 29-04-2020 11 1   Download

Aminolevulinic acid (ALA) is found as one of the potential plant growth regulator which is involved in the development of heme, chlorophyll, bilins, vitamin B and other specialized plant products. ALA has a significant role in stress adaptation in plants through regulating several key physiological processes associated with plant adaptations such as seed germination, reduced Na+ uptake, altered light reactions, improved scavenging of reactive oxygen species, enhanced photosynthetic assimilation and maintenance of nutrients status.

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After studying this chapter, you should be able to accomplish the following outcomes: List the types of organisms that carry on photosynthesis; identify the main pars of a chloroplast; show that photosynthesis is a redox reaction that produces a carbohydrate and releases O2;...

46p tangtuy07 02-04-2016 41 2   Download

The photosynthetic protein complexes in plants are located in the chloroplast thylakoid membranes. These membranes have an ultrastructure that consists of tightly stackedÔgranaÕ regions interconnectedbyunstackedmembrane regions.The structure of isolated granamembranes has been studiedhere by cryo-electron microscopy. The data reveals an unusual arrangement of the photosynthetic protein complexes, staggered over two tightly stacked planes.

11p research12 29-04-2013 40 1   Download

The core complex ofRhodobacter sphaeroidesis formed by the association of the light-harvesting antenna 1 (LH1) and the reaction center (RC). The PufX protein is essential for photosynthetic growth; it is locatedwithin the core in a 1 : 1 stoichiometry with the RC. PufX is required for a fast ubiquinol exchange between the QBsite of the RC and the Qo site of the cytochromebc1complex.

9p research12 23-04-2013 31 1   Download

We briefly review the metabolism of the chloroplast stroma, and describe the structural modelling technique of elementary modes analysis. The technique is applied to a model of chloroplast metabolism to investigate viable pathways in the light, in the dark, and in the dark with the addition of sedoheptulose-1,7-bisphosphatase (nor-mally inactive in the dark).

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Transmembrane proton translocation in the photosynthetic membranes of the purple bacteriumRhodobacter sphaero-ides is driven by light and performed by two transmem-brane complexes; the photosynthetic reaction center and the ubiquinol–cytochromecoxidoreductase complex, coupled by two mobile electron carriers; the cytochrome and the quinone. This paper focuses on the kinetics and thermo-dynamics of the interaction between the lipophylic electron carrier ubiquinone-10 and the photosynthetic enzyme reconstituted in liposomes. ...

11p fptmusic 12-04-2013 52 1   Download

We measured cocrystals of the membrane protein Photosystem I with its soluble electron acceptor ferredoxin for the first time at the ALS (Berkeley, CA). Previous data collected at our home source and at other synchrotron sources showed crystals with very high mosaicity (2–5%) and a diffraction limit to 7–8 Aresolution. This first beamtime at ALS was very successful and may represent a breakthrough for the determination of the crystal structure. 110 crystals, grown under modified crystallization conditions, were scanned and for the first time, crystals diffraction to 3.5 A were observed....

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LIFE ON EARTH ULTIMATELY DEPENDS ON ENERGY derived from the sun. Photosynthesis is the only process of biological importance that can harvest this energy. In addition, a large fraction of the planet’s energy resources results from photosynthetic activity in either recent or ancient times (fossil fuels). This chapter introduces the basic physical principles that underlie photosynthetic energy storage and the current understanding of the structure and function of the photosynthetic apparatus (Blankenship 2002). The term photosynthesis means literally “synthesis using light.

36p anhphuonggl 11-04-2013 74 9   Download

Heme oxygenase (HO) catalyzes the oxidative degradation of heme utilizing molecular oxygen and reducing equiva-lents. In photosynthetic organisms, HO functions in the biosynthesis of such open-chain tetrapyrroles as phyto-chromobilin and phycobilins, which are involved in the sig-nal transduction for light responses and light harvesting for photosynthesis, respectively.

9p awards 05-04-2013 30 2   Download

Exposure ofArabidopsis thalianaplants to high levels of light revealed specific phosphorylation of a 40 kDa protein in photosynthetic thylakoid membranes. The protein was identified by MS as extracellular calcium-sensing receptor (CaS), previously reported to be located in the plasma membrane.

11p media19 06-03-2013 42 1   Download

In dense plant populations, individuals shade each other resulting in a low-light habitat that is enriched in far-red light. This light quality gradient decreases the efficiency of the photosynthetic light reaction as a result of imbalanced excitation of the two photosystems. Plants counteract such con-ditions by performing acclimation reactions.

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Native and Ca 2+ -depleted light-harvesting–reaction center core complexes (LH1–RC) from the photosynthetic bacterium Thermochromatium(Tch.) tepidum exhibit maximal LH1–Qy absorption at 915 and 889 nm, respec-tively. To understand the structural origins of the spectral variation, we performed spectroscopic and structure modeling investigations.

11p vinaphone15 27-02-2013 50 3   Download

Microalgae are prokaryotic or eukaryotic photosynthetic microorganisms that can grow rapidly and live in a wide range of ecosystems extending from terrestrial to aquatic environment. Environmental factors such as temperature, UV-light, irradiance, drought and salinity are known to affect their photosynthesis. Photosynthesis was the most sensitive process in microalgae, leading to numerous changes in structure and function of the photosynthetic apparatus under various conditions.

412p conquynho32 15-09-2012 73 10   Download