Lipidomic Profiling of Rice Bran after Green Solid-Liquid Extractions for the Development of Circular Economy Approaches.

Rice bran is a rather underutilized by-product of the rice industry that nowadays is far from being valorized. In this study, the lipidomic profile of bran of the Italian rice variety, Roma, has been evaluated through ultra performance liquid chromatography-tandem mass spectrometry. Crude lipid extracts were obtained from rice bran treated with different green solvents (1-butanol, ethanol and methyl tert-butyl ether/methanol mixture) in combination with an ultrasonic pre-treatment, and then compared with extracts obtained with standard solvents (chloroform/methanol mixture).

A green and easy-to-assemble electrochemical biosensor based on thylakoid membranes for photosynthetic herbicides detection.

In this study, we report on an easy-to-assemble amperometric electrochemical biosensor incorporating thylakoid membranes for the detection of photosynthetic herbicides. These molecules interfere with the light-induced photosynthetic electron transport occurring at the level of the photosystems within the thylakoid membranes, thus reducing the current of the associated bioelectrode. Thylakoid membranes isolated from pea plants were adsorbed directly on a bare carbon paper working electrode and placed in the measurement cell in the absence of any electrochemical mediator, obtaining a fully environmental-friendly biodevice capable of photocurrent densities up to 14 μA/cm.

Channeling Anabolic Side Products toward the Production of Nonessential Metabolites: Stable Malate Production in sp. PCC6803.

Powered by (sun)light to oxidize water, cyanobacteria can directly convert atmospheric CO into valuable carbon-based compounds and meanwhile release O to the atmosphere. As such, cyanobacteria are promising candidates to be developed as microbial cell factories for the production of chemicals. Nevertheless, similar to other microbial cell factories, engineered cyanobacteria may suffer from production instability.

Binding Properties of Photosynthetic Herbicides with the Q Site of the D1 Protein in Plant Photosystem II: A Combined Functional and Molecular Docking Study.

Photosystem II (PSII) is a multi-subunit enzymatic complex embedded in the thylakoid membranes responsible for the primary photosynthetic reactions vital for plants. Many herbicides used for weed control inhibit PSII by interfering with the photosynthetic electron transport at the level of the D1 protein, through competition with the native plastoquinone for the Q site. Molecular details of the interaction of these herbicides in the D1 Q site remain to be elucidated in plants.

High-Light versus Low-Light: Effects on Paired Photosystem II Supercomplex Structural Rearrangement in Pea Plants.

In plant thylakoid membranes Photosystem II (PSII) associates with a variable number of antenna proteins (LHCII) to form different types of supercomplexes (PSII-LHCII), whose organization is dynamically adjusted in response to light cues, with the CS more abundant in high-light and the CSM in low-light. Paired PSII-LHCII supercomplexes interacting at their stromal surface from adjacent thylakoid membranes were previously suggested to mediate stacking. Here, we present the cryo-electron microscopy maps of paired CS and CSM supercomplexes isolated from pea plants grown in high-light and low-light, respectively.

How paired PSII-LHCII supercomplexes mediate the stacking of plant thylakoid membranes unveiled by structural mass-spectrometry.

Grana are a characteristic feature of higher plants' thylakoid membranes, consisting of stacks of appressed membranes enriched in Photosystem II (PSII) and associated light-harvesting complex II (LHCII) proteins, together forming the PSII-LHCII supercomplex. Grana stacks undergo light-dependent structural changes, mainly by reorganizing the supramolecular structure of PSII-LHCII supercomplexes. LHCII is vital for grana formation, in which also PSII-LHCII supercomplexes are involved.

Structural and functional differentiation of the light-harvesting protein Lhcb4 during land plant diversification.

About 475 million years ago, plants originated from an ancestral green alga and evolved first as non-vascular and later as vascular plants, becoming the primary producers of biomass on lands. During that time, the light-harvesting complex II (LHCII), responsible for sunlight absorption and excitation energy transfer to the photosystem II (PSII) core, underwent extensive differentiation. Lhcb4 is an ancestral LHCII that, in flowering plants, differentiated into up to three isoforms, Lhcb4.

Response of the thylakoid proteome of Synechocystis sp. PCC 6803 to photohinibitory intensities of orange-red light.

Photoautotrophic growth of Synechocystis sp. PCC 6803 in a flat-panel photobioreactor, run in turbidostat mode under increasing intensities of orange-red light (636 nm), showed a maximal growth rate (0.12 h) at 300 μmol m s, whereas first signs of photoinhibition were detected above 800 μmol m s.

Isolation and characterization of a photosystem II preparation from thylakoid membranes of the extreme halophyte Salicornia veneta Pignatti et Lausi.

Salicornia veneta (Pignatti et Lausi) is an extreme halophyte living in salt marsh where NaCl concentration may be as high as 1 M. Here we report on the isolation and characterization of a PSII preparation obtained by Triton X-100 solubilisation of the thylakoid membrane. By a combination of gel electrophoresis, immunoblotting and mass spectrometry, the depletion of a number of PSII proteins such as PsbQ, PsbM and PsbT was highlighted.

Thylakoid proteome modulation in pea plants grown at different irradiances: quantitative proteomic profiling in a non-model organism aided by transcriptomic data integration.

Plant thylakoid membranes contain hundreds of proteins that closely interact to cope with ever-changing environmental conditions. We investigated how Pisum sativum L. (pea) grown at different irradiances optimizes light-use efficiency through the differential accumulation of thylakoid proteins.

Analysis of the light intensity dependence of the growth of and of the light distribution in a photobioreactor energized by 635 nm light.

gathered momentum in modelling studies and biotechnological applications owing to multiple factors like fast growth, ability to fix carbon dioxide into valuable products, and the relative ease of genetic manipulation. physiology and metabolism, and consequently, the productivity of -based photobioreactors (PBRs), are heavily light modulated. Here, we set up a turbidostat-controlled lab-scale cultivation system in order to study the influence of varying orange-red light intensities on growth characteristics and photosynthetic activity.

In pea stipules a functional photosynthetic electron flow occurs despite a reduced dynamicity of LHCII association with photosystems.

The flexible association of the light harvesting complex II (LHCII) to photosystem (PS) I and PSII to balance their excitation is a major short-term acclimation process of the thylakoid membrane, together with the thermal dissipation of excess absorbed energy, reflected in non-photochemical quenching of chlorophyll fluorescence (NPQ). In Pisum sativum, the leaf includes two main photosynthetic parts, the basal stipules and the leaflets. Since the stipules are less efficient in carbon fixation than leaflets, the adjustments of the thylakoid system, which safeguard the photosynthetic membrane against photodamage, were analysed.

Pea PSII-LHCII supercomplexes form pairs by making connections across the stromal gap.

In higher plant thylakoids, the heterogeneous distribution of photosynthetic protein complexes is a determinant for the formation of grana, stacks of membrane discs that are densely populated with Photosystem II (PSII) and its light harvesting complex (LHCII). PSII associates with LHCII to form the PSII-LHCII supercomplex, a crucial component for solar energy conversion. Here, we report a biochemical, structural and functional characterization of pairs of PSII-LHCII supercomplexes, which were isolated under physiologically-relevant cation concentrations.

Use of Nicotiana tabacum transplastomic plants engineered to express a His-tagged CP47 for the isolation of functional photosystem II core complexes.

This work focuses on the development of a molecular tool for purification of Photosystem II (PSII) from Nicotiana tabacum (L.). To this end, the chloroplast psbB gene encoding the CP47 PSII subunit was replaced with an engineered version of the same gene containing a C-terminal His-tag.

Dynamic reorganization of photosystem II supercomplexes in response to variations in light intensities.

Plants are sessile organisms and need to acclimate to ever-changing light conditions in order to survive. These changes trigger a dynamic reorganization of the membrane protein complexes in the thylakoid membranes. Photosystem II (PSII) and its light harvesting system (LHCII) are the major target of this acclimation response, and accumulating evidences indicate that the amount and composition of PSII-LHCII supercomplexes in thylakoids are dynamically adjusted in response to changes in light intensity and quality.

Isolation of novel PSII-LHCII megacomplexes from pea plants characterized by a combination of proteomics and electron microscopy.

In higher plants, photosystem II (PSII) is a multi-subunit pigment-protein complex embedded in the thylakoid membranes of chloroplasts, where it is present mostly in dimeric form within the grana. Its light-harvesting antenna system, LHCII, is composed of trimeric and monomeric complexes, which can associate in variable number with the dimeric PSII core complex in order to form different types of PSII-LHCII supercomplexes. Moreover, PSII-LHCII supercomplexes can laterally associate within the thylakoid membrane plane, thus forming higher molecular mass complexes, termed PSII-LHCII megacomplexes (Boekema et al.

Analysis of the transgenerational iron deficiency stress memory in Arabidopsis thaliana plants.

We investigated the existence of the transgenerational memory of iron (Fe) deficiency stress, in Arabidopsis thaliana. Plants were grown under Fe deficiency/sufficiency, and so were their offspring. The frequency of somatic homologous recombination (SHR) events, of DNA strand breaks as well as the expression of the transcription elongation factor TFIIS-like gene increase when plants are grown under Fe deficiency.

Outer Co(II) ions in Co-ZIF-67 reversibly adsorb oxygen from both gas phase and liquid water.

Outer Co(II) species in Co-ZIF-67 coordinate molecular oxygen both from the gas phase and liquid water, through an adsorption process (presumably yielding in both cases surface superoxo species), respectively weak and reversible (gas phase), and strong and irreversible (liquid); in the latter case desorption is however brought about by illumination with solar light comprising the UV component.

Light-dependent reversible phosphorylation of the minor photosystem II antenna Lhcb6 (CP24) occurs in lycophytes.

Evolution of vascular plants required compromise between photosynthesis and photodamage. We analyzed representative species from two divergent lineages of vascular plants, lycophytes and euphyllophytes, with respect to the response of their photosynthesis and light-harvesting properties to increasing light intensity. In the two analyzed lycophytes, Selaginella martensii and Lycopodium squarrosum, the medium phase of non-photochemical quenching relaxation increased under high light compared to euphyllophytes.

Proteomic characterization and three-dimensional electron microscopy study of PSII-LHCII supercomplexes from higher plants.

In higher plants a variable number of peripheral LHCII trimers can strongly (S), moderately (M) or loosely (L) associate with the dimeric PSII core (C2) complex via monomeric Lhcb proteins to form PSII-LHCII supercomplexes with different structural organizations. By solubilizing isolated stacked pea thylakoid membranes either with the α or β isomeric forms of the detergent n-dodecyl-D-maltoside, followed by sucrose density ultracentrifugation, we previously showed that PSII-LHCII supercomplexes of types C2S2M2 and C2S2, respectively, can be isolated [S. Barera et al.

Structural, functional and auxiliary proteins of photosystem II.

Photosystem II (PSII) is the water-splitting enzyme complex of photosynthesis and consists of a large number of protein subunits. Most of these proteins have been structurally and functionally characterized, although there are differences between PSII of plants, algae and cyanobacteria. Here we catalogue all known PSII proteins giving a brief description, where possible of their genetic origin, physical properties, structural relationships and functions.

Characterization of PSII-LHCII supercomplexes isolated from pea thylakoid membrane by one-step treatment with α- and β-dodecyl-D-maltoside.

It was the work of Jan Anderson, together with Keith Boardman, that showed it was possible to physically separate photosystem I (PSI) from photosystem II (PSII), and it was Jan Anderson who realized the importance of this work in terms of the fluid-mosaic model as applied to the thylakoid membrane. Since then, there has been a steady progress in the development of biochemical procedures to isolate PSII and PSI both for physical and structural studies. Dodecylmaltoside (DM) has emerged as an effective mild detergent for this purpose.

Biomimetic soluble collagen purified from bones.

Type I collagen has been extensively exploited as a biomaterial for biomedical applications and drug delivery; however, small molecular alterations occurring during the isolation procedure and its interaction with residual bone extracellular matrix molecules or proteins might affect the overall material biocompatibility and performance. The aim of the current work is to study the potential alterations in collagen properties and organization associated with the absence of proteoglycans, which mimic pathological conditions associated with age-related diseases. A new approach for evaluating the effect of proteoglycans on the properties of isolated type I collagen from the bone matrix is described.