Insights into the effects of phenolic compounds on the growth of Chlorella vulgaris: The case of olive mill wastewater.

Olive mill wastewaters (OMWW) are characterized by a large concentration of pollutants, among which polyphenols represent a large part. This study investigated the effect of different dilutions of a culture medium enriched with olive-derived phenolic compounds on Chlorella vulgaris growth and its ability to degrade each one of them. In particular, polyphenols were precisely identified and quantified by HPLC-DAD analysis, showing high removal efficiency by C.

An unusual triplet population pathway in the Reaction Centre of the Chlorophyll-d binding Photosystem I of A. marina, as revealed by a combination of TR-EPR and ODMR spectroscopies.

Photo-induced Chlorophyll (Chl) triplet states in the isolated Photosystem I (PSI) of Acaryochloris marina, that harbours Chl d as its main pigment, were investigated by Optically Detected Magnetic Resonance (ODMR) and Time-Resolved Electron Paramagnetic Resonance (TR-EPR), and as a function of pre-illumination of the sample under reducing redox poising. Fluorescence Detected Magnetic Resonance (FDMR) allowed resolving four Chl d triplet (Chl d) populations (T-T) both in untreated and illuminated samples in the presence of ascorbate and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD). The FDMR signals increased following the pre-illumination treatment, particularly for the T and T populations, which are therefore sensitive to the redox state of PSI cofactors.

Thermodynamic Factors Controlling Electron Transfer among the Terminal Electron Acceptors of Photosystem I: Insights from Kinetic Modelling.

Photosystem I is a key component of primary energy conversion in oxygenic photosynthesis. Electron transfer reactions in Photosystem I take place across two parallel electron transfer chains that converge after a few electron transfer steps, sharing both the terminal electron acceptors, which are a series of three iron-sulphur (Fe-S) clusters known as FX, FA, and FB, and the terminal donor, P700. The two electron transfer chains show kinetic differences which are, due to their close geometrical symmetry, mainly attributable to the tuning of the physicochemical reactivity of the bound cofactors, exerted by the protein surroundings.

Recombinant human placental growth factor-2 in post-infarction left ventricular dysfunction: a randomized, placebo-controlled, preclinical study.

Placental growth factor (PlGF)-2 induces angio- and arteriogenesis in rodents but its therapeutic potential in a clinically representative post-infarction left ventricular (LV) dysfunction model remains unclear. We, therefore, investigated the safety and efficacy of recombinant human (rh)PlGF-2 in the infarcted porcine heart in a randomized, placebo-controlled blinded study. We induced myocardial infarction (MI) in pigs using 75 min mid-LAD balloon occlusion followed by reperfusion.

Temperature-Dependent Olive Pomace Extraction for Obtaining Bioactive Compounds Preventing the Death of Murine Cortical Neurons.

High-pressure and temperature extraction (HPTE) can effectively recover bioactive compounds from olive pomace (OP). HPTE extract obtained by extracting OP with ethanol and water (50:50 /) at 180 °C for 90 min demonstrated a pronounced ability to preserve intracellular calcium homeostasis, shielding neurons from the harmful effects induced by N-methyl-d-aspartate (NMDA) receptor (NMDAR) overactivation, such as aberrant calpain activation. In this study, the extraction temperature was changed from 37 to 180 °C, and the extracts were evaluated for their antioxidant potency and ability to preserve crucial intracellular Ca-homeostasis necessary for neuronal survival.

From laboratory- to industrial-scale plants: Future of anaerobic digestion of olive mill solid wastes.

In this review, the main properties of olive mill solid waste, the primary by-product of olive oil production, and its feasibility as a feedstock for anaerobic digesters operating at laboratory-, pilot- and industrial-scales are discussed in detail. Nutrient addition and thermal pretreatments were found to have the potential to address the challenges arising from the high carbon-to-nitrogen ratio, the low pH, and the high concentration of phenolic compounds. Furthermore, anaerobic co-digestion with different organic feedstocks has been identified as one of the most promising options to solve the aforementioned problems and the seasonality nature of olive waste, while improving the efficiency of anaerobic treatment plants that operate throughout the whole year.

Investigating the Effect of Operational Variables on the Yield, Characterization, and Properties of End-of-Life Olive Stone Biomass Pyrolysis Products.

In recent years, biomass has emerged as a promising raw material to produce various products, including hydrocarbons, platform chemicals, and fuels. However, a more comprehensive evaluation of the potential production of desirable value-added products and chemical intermediates is required. For these reasons, this study aimed to investigate the impact of various operating parameters on the pyrolysis of end-of-life olive stone, an agriculture and food industry waste, using a tubular quartz reactor operated at 773 K.

Inulin as prebiotic encapsulating agent for the production of spray-dried L. tea microcapsules.

Due to the high content of phenolics and anthocyanins of L. tea and the sensibility of these bioactive compounds, this work aimed to optimize the obtention of microcapsules by spray-drying, using inulin as a carrier agent. Using a Box-Behnken Design, the effects of inlet temperature (130, 150, and 170 °C), feed flow rate (5, 10, and 15 mL min), and inulin concentration (5, 10, and 15 g L) were evaluated.

Chlorophyll triplet states in thylakoid membranes of Acaryochloris marina. Evidence for a triplet state sitting on the photosystem I primary donor populated by intersystem crossing.

Photo-induced triplet states in the thylakoid membranes isolated from the cyanobacterium Acaryocholoris marina, that harbours Chlorophyll (Chl) d as its main chromophore, have been investigated by Optically Detected Magnetic Resonance (ODMR) and time-resolved Electron Paramagnetic Resonance (TR-EPR). Thylakoids were subjected to treatments aimed at poising the redox state of the terminal electron transfer acceptors and donors of Photosystem II (PSII) and Photosystem I (PSI), respectively. Under ambient redox conditions, four Chl d triplet populations were detectable, identifiable by their characteristic zero field splitting parameters, after deconvolution of the Fluorescence Detected Magnetic Resonance (FDMR) spectra.

Role of pheophytin a in the primary charge separation of photosystem I from Acaryochloris marina: Femtosecond optical studies of excitation energy and electron transfer reactions.

Photosystem I (PSI) of the cyanobacterium Acaryochloris marina is capable of performing an efficient photoelectrochemical conversion of far-red light due to its unique suite of cofactors. Chlorophyll d (Chl-d) has been long known as the major antenna pigment in the PSI from A. marina, while the exact cofactor composition of the reaction centre (RC) was established only recently by cryo-electron microscopy.

Temperature-induced zeaxanthin overproduction in Synechococcus elongatus PCC 7942.

The exogenous crtZ gene from Brevundimonas sp. SD212, coding for a 3,3' β-car hydroxylase, was expressed in Synechococcus elongatus PCC 7942 under the control of a temperature-inducible promoter in an attempt to engineer the carotenoid metabolic pathway, to increase the content of zeaxanthin and its further hydroxylated derivatives caloxanthin and nostoxanthin. These molecules are of particular interest due to their renowned antioxidant properties.

Ultrafast excited state dynamics in the monomeric and trimeric photosystem I core complex of Spirulina platensis probed by two-dimensional electronic spectroscopy.

Photosystem I (PSI), a naturally occurring supercomplex composed of a core part and a light-harvesting antenna, plays an essential role in the photosynthetic electron transfer chain. Evolutionary adaptation dictates a large variability in the type, number, arrangement, and absorption of the Chlorophylls (Chls) responsible for the early steps of light-harvesting and charge separation. For example, the specific location of long-wavelength Chls (referred to as red forms) in the cyanobacterial core has been intensively investigated, but the assignment of the chromophores involved is still controversial.

Enhanced Antitumor Efficacy of PhAc-ALGP-Dox, an Enzyme-Activated Doxorubicin Prodrug, in a Panel of THOP1-Expressing Patient-Derived Xenografts of Soft Tissue Sarcoma.

Despite poor response rates and dose-limiting cardiotoxicity, doxorubicin (doxo) remains the standard-of-care for patients with advanced soft tissue sarcoma. We evaluated the efficacy of two tetrapeptidic doxo prodrugs (PhAc-ALGP-Dox or CBR-049 and CBR-050) that are locally activated by enzymes expressed in the tumor environment, in ten sarcoma patient-derived xenografts. Xenograft models were selected based on expression of the main activating enzyme, i.

PhAc-ALGP-Dox, a Novel Anticancer Prodrug with Targeted Activation and Improved Therapeutic Index.

Clinical use of doxorubicin (Dox) is limited by cumulative myelo- and cardiotoxicity. This research focuses on the detailed characterization of PhAc-ALGP-Dox, a targeted tetrapeptide prodrug with a unique dual-step activation mechanism, designed to circumvent Dox-related toxicities and is ready for upcoming clinical investigation. Coupling Dox to a phosphonoacetyl (PhAc)-capped tetrapeptide forms the cell-impermeable, inactive compound, PhAc-ALGP-Dox.

Direct Evidence for Excitation Energy Transfer Limitations Imposed by Low-Energy Chlorophylls in Photosystem I-Light Harvesting Complex I of Land Plants.

The overall efficiency of photosynthetic energy conversion depends both on photochemical and excitation energy transfer processes from extended light-harvesting antenna networks. Understanding the trade-offs between increase in the antenna cross section and bandwidth and photochemical conversion efficiency is of central importance both from a biological perspective and for the design of biomimetic artificial photosynthetic complexes. Here, we employ two-dimensional electronic spectroscopy to spectrally resolve the excitation energy transfer dynamics and directly correlate them with the initial site of excitation in photosystem I-light harvesting complex I (PSI-LHCI) supercomplex of land plants, which has both a large antenna dimension and a wide optical bandwidth extending to energies lower than the peak of the reaction center chlorophylls.

On wavelength-dependent exciton lifetime distributions in reconstituted CP29 antenna of the photosystem II and its site-directed mutants.

To provide more insight into the excitonic structure and exciton lifetimes of the wild type (WT) CP29 complex of photosystem II, we measured high-resolution (low temperature) absorption, emission, and hole burned spectra for the A2 and B3 mutants, which lack chlorophylls a612 and b614 (Chls), respectively. Experimental and modeling results obtained for the WT CP29 and A2/B3 mutants provide new insight on the mutation-induced changes at the molecular level and shed more light on energy transfer dynamics. Simulations of the A2 and B3 optical spectra, using the second-order non-Markovian theory, and comparison with improved fits of WT CP29 optical spectra provide more insight into their excitonic structure, mutation induced changes, and frequency-dependent distributions of exciton lifetimes (T).

Repetitive non-destructive extraction of lipids from Chlorella vulgaris grown under stress conditions.

The aim of this study was the investigation of non-destructive lipid extraction from Chlorella vulgaris grown under stress conditions of nutrient limitation and salinity. To select a suitable solvent for extraction, the performances of decane, dodecane and hexadecane were tested based on their effect on lipid extraction and cell viability. The results showed that dodecane was the most suitable solvent for the extraction process.

A Bioactive Olive Pomace Extract Prevents the Death of Murine Cortical Neurons Triggered by NMDAR Over-Activation.

We have recently demonstrated that bioactive molecules, extracted by high pressure and temperature from olive pomace, counteract calcium-induced cell damage to different cell lines. Here, our aim was to study the effect of the same extract on murine cortical neurons, since the preservation of the intracellular Ca-homeostasis is essential for neuronal function and survival. Accordingly, we treated neurons with different stimuli in order to evoke cytotoxic glutamatergic activation.

Ultrafast excited-state dynamics in land plants Photosystem I core and whole supercomplex under oxidised electron donor conditions.

The kinetics of excited-state energy migration were investigated by femtosecond transient absorption in the isolated Photosystem I-Light-Harvesting Complex I (PSI-LHCI) supercomplex and in the isolated PSI core complex of spinach under conditions in which the terminal electron donor P is chemically pre-oxidised. It is shown that, under these conditions, the relaxation of the excited state is characterised by lifetimes of about 0.4 ps, 4.

A Comparison of Constitutive and Inducible Non-Endogenous Keto-Carotenoids Biosynthesis in sp. PCC 6803.

The model cyanobacterium sp. PCC 6803 has gained significant attention as an alternative and sustainable source for biomass, biofuels and added-value compounds. The latter category includes keto-carotenoids, which are molecules largely employed in a wide spectrum of industrial applications in the food, feed, nutraceutical, cosmetic and pharmaceutical sectors.

Kinetics and Energetics of Phylloquinone Reduction in Photosystem I: Insight From Modeling of the Site Directed Mutants.

Two phylloquinone molecules ( ), one being predominantly coordinated by PsaA subunit residues ( ) the other by those of PsaB ( ), act as intermediates in the two parallel electron transfer chains of Photosystem I. The oxidation kinetics of the two phyllosemiquinones by the iron-sulfur cluster F differ by approximately one order of magnitude, with being oxidized in about 200 ns and in about 20 ns. These differences are generally explained in terms of asymmetries in the driving force for F reduction on the two electron transfer chains.

Modelling electron transfer in photosystem I: limits and perspectives.

Uncovering the parameters underlying the electron transfer (ET) in photosynthetic reaction centres is of importance for understanding the molecular mechanisms underpinning their functionality. The reductive nature of most cofactors involved in photosynthetic ET makes the direct estimation of their properties difficult. Photosystem I (PSI) operates in a highly reducing regime, making the assessment of cofactor properties even more difficult.

Comparative excitation-emission dependence of the F /F ratio in model green algae and cyanobacterial strains.

The emission spectra collected under conditions of open (F ) and closed (F ) photosystem II (PSII) reaction centres are close-to-independent from the excitation wavelength in Chlamydomonas reinhardtii and Chlorella sorokiniana, whereas a pronounced dependence is observed in Synechocystis sp. PCC6803 and Synechococcus PCC7942, instead. The differences in band-shape between the F and F emission are limited in green algae, giving rise only to a minor trough in the F /F spectrum in the 705-720 nm range, irrespectively of the excitation.

Non-endogenous ketocarotenoid accumulation in engineered Synechocystis sp. PCC 6803.

The cyanobacterium Synechocystis sp. PCC 6803 is a model species commonly employed for biotechnological applications. It is naturally able to accumulate zeaxanthin (Zea) and echinenone (Ech), but not astaxanthin (Asx), which is the highest value carotenoid produced by microalgae, with a wide range of applications in pharmaceutical, cosmetics, food and feed industries.