Search results for "Chlorophyll"
showing 10 items of 453 documents
Expression of a higher plant light-harvesting chlorophyll a/b-binding protein in Synechocystis sp. PCC 6803
1999
A chimeric lhcb gene, coding for Lhcb, a higher plant chlorophyll a/b-binding light-harvesting complex of photosystem II (LHCII), was constructed using the Synechocystis sp. PCC 6803 psbA3 promoter and a modified lhcb gene from pea. This construct drives synthesis of full-length, mature Lhcb under the control of the strong psbA3 promoter that usually drives expression of the D1 protein of photosystem II. This chimeric gene was transformed into a photosystem I-less/chlL(-) Synechocystis sp. PCC 6803 strain that is unable to synthesize chlorophyll in darkness. In the resulting strain, a high level of lhcb transcript was detected and transcript accumulation was enhanced by addition of exogenou…
Water soluble chlorophyll binding protein of higher plants: A most suitable model system for basic analyses of pigment–pigment and pigment–protein in…
2011
Abstract This short review paper describes spectroscopic studies on pigment–pigment and pigment–protein interactions of chlorophyll (Chl) a and b bound to the recombinant protein of class IIa water soluble chlorophyll protein (WSCP) from cauliflower. Two Chls form a strongly excitonically coupled open sandwich dimer within the tetrameric protein matrix. In marked contrast to the mode of excitonic coupling of Chl and bacterio-Chl molecules in light harvesting complexes and reaction centers of all photosynthetic organisms, the unique structural pigment array in the Chl dimer of WSCP gives rise to an upper excitonic state with a large oscillator strength. This property opens the way for thorou…
Up-regulation of 1-deoxy-D-xylulose-5-phosphate synthase enhances production of essential oils in transgenic spike lavender.
2006
Abstract Spike lavender (Lavandula latifolia) is an aromatic shrub cultivated worldwide for the production of essential oils. The major constituents of these oils are monoterpenes, which are obtained from isopentenyl diphosphate and dimethylallyl diphosphate precursors through the plastidial methylerythritol phosphate (MEP) pathway and/or the cytosolic mevalonate pathway. 1-Deoxy-d-xylulose-5-P synthase (DXS) catalyzes the first step of the MEP pathway. A cDNA coding for the Arabidopsis (Arabidopsis thaliana) DXS was constitutively expressed in spike lavender. Gas chromatography/mass spectrometry analyses revealed that transgenic plants accumulated significantly more essential oils compared…
Deoxyxylulose 5-phosphate reductoisomerase is not a rate-determining enzyme for essential oil production in spike lavender
2014
[EN] Spike lavender (Lavandula latifolia) is an economically important aromatic plant producing essential oils, whose components (mostly monoterpenes) are mainly synthesized through the plastidial methylerythritol 4-phosphate (MEP) pathway. 1-Deoxy-d-xylulose-5-phosphate (DXP) synthase (DXS), that catalyzes the first step of the MEP pathway, plays a crucial role in monoterpene precursors biosynthesis in spike lavender. To date, however, it is not known whether the DXP reductoisomerase (DXR), that catalyzes the conversion of DXP into MEP, is also a rate-limiting enzyme for the biosynthesis of monoterpenes in spike lavender. To investigate it, we generated transgenic spike lavender plants con…
Modulation of the growth and metabolic response of cyanobacteria by the multifaceted activity of naringenin
2017
The interactions between the plant-derived bioflavonoid, naringenin, and prokaryotic microalgae representatives (cyanobacteria), were investigated with respect to its influence on the growth and metabolic response of these microorganisms. To achieve reliable results, the growth of cyanobacteria was determined based on measurements of chlorophyll content, morphological changes were assessed through microscopic observations, and the chemical response of cells was determined using liquid and gas chromatography (HPLC; GC-FID). The results show that micromolar levels of naringenin stimulated the growth of cyanobacteria. Increased growth was observed for halophilic strains at naringenin concentra…
Dynamics of Two Picophytoplankton Groups in Mediterranean Sea: Analysis of the Deep Chlorophyll Maximum by a Stochastic Advection-Reaction-Diffusion …
2013
A stochastic advection-reaction-diffusion model with terms of multiplicative white Gaussian noise, valid for weakly mixed waters, is studied to obtain the vertical stationary spatial distributions of two groups of picophytoplankton, i.e., picoeukaryotes and Prochlorococcus, which account about for 60% of total chlorophyll on average in Mediterranean Sea. By numerically solving the equations of the model, we analyze the one-dimensional spatio-temporal dynamics of the total picophytoplankton biomass and nutrient concentration along the water column at different depths. In particular, we integrate the equations over a time interval long enough, obtaining the steady spatial distributions for th…
The Folding State of the Lumenal Loop Determines the Thermal Stability of Light-Harvesting Chlorophyll a/b Protein
2004
The major light-harvesting protein of photosystem II (LHCIIb) is the most abundant chlorophyll-binding protein in the thylakoid membrane. It contains three membrane-spanning alpha helices; the first and third one closely interact with each other to form a super helix, and all three helices bind most of the pigment cofactors. The protein loop domains connecting the alpha helices also play an important role in stabilizing the LHCIIb structure. Single amino acid exchanges in either loop were found to be sufficient to significantly destabilize the complex assembled in vitro [Heinemann, B., and Paulsen, H. (1999) Biochemistry 38, 14088-14093. Mick, V., Eggert, K., Heinemann, B., Geister, S., and…
The Light-Harvesting Chlorophyll a/b Complex Can Be Reconstituted in Vitro from Its Completely Unfolded Apoprotein
2003
The major light-harvesting chlorophyll a/b protein (LHCIIb) of higher plants is one of the few membrane proteins that can be refolded in vitro. During folding, the apoprotein is assembled with pigments to form a structurally authentic and functional pigment--protein complex. All reconstitution procedures used so far include solubilization of the apoprotein in sodium dodecyl sulfate (SDS) where the protein adopts approximately half of its alpha-helical folding present in the native structure. This paper shows that this preformed alpha-helix is not a prerequisite for LHCIIb folding in vitro. The apoprotein can also be reconstituted starting from a solution in guanidinium hydrochloride (Gnd) w…
Chlamydomonas reinhardtii in the landscape of pigments.
2004
▪ Abstract This review focuses on the biosynthesis of pigments in the unicellular alga Chlamydomonas reinhardtii and their physiological and regulatory functions in the context of information gathered from studies of other photosynthetic organisms. C. reinhardtii is serving as an important model organism for studies of photosynthesis and the pigments associated with the photosynthetic apparatus. Despite extensive information pertaining to the biosynthetic pathways critical for making chlorophylls and carotenoids, we are just beginning to understand the control of these pathways, the coordination between pigment and apoprotein synthesis, and the interactions between the activities of these…
Gaussian processes retrieval of leaf parameters from a multi-species reflectance, absorbance and fluorescence dataset.
2013
Abstract: Biochemical and structural leaf properties such as chlorophyll content (Chl), nitrogen content (N), leaf water content (LWC), and specific leaf area (SLA) have the benefit to be estimated through nondestructive spectral measurements. Current practices, however, mainly focus on a limited amount of wavelength bands while more information could be extracted from other wavelengths in the full range (400-2500 nm) spectrum. In this research, leaf characteristics were estimated from a field-based multi-species dataset, covering a wide range in leaf structures and Chl concentrations. The dataset contains leaves with extremely high Chl concentrations (>100 mu g cm(-2)), which are seldom es…