Amber ale beer enriched with goji berries - The effect on bioactive compound content and sensorial properties.

Goji berries, traditionally used in Chinese medicine, are nowadays gaining popularity in the Western world. Efforts are made to enlarge the offer of goji containing foods. In this study, goji berries were added to ale type beer at different stages of the production process in order to develop a beverage with desirable sensory characteristic and high antioxidant capacity.

A new chemical tool for absinthe producers, quantification of α/β-thujone and the bitter components in Artemisia absinthium.

The concentrations of α/β-thujone and the bitter components of Artemisia absinthium were quantified from alcoholic wormwood extracts during four phenological stages of their harvest period. A solid-phase micro-extraction method coupled to gas chromatography-mass spectrometry was used to determine the concentration of the two isomeric forms of thujone. In parallel, the combination of ultra-high pressure liquid chromatography and high resolution mass spectrometry allowed to quantify the compounds absinthin, artemisetin and dihydro-epi-deoxyarteannuin B.

Quantification of the production of hydrogen peroxide H2O2 during accelerated wine oxidation.

Understanding how wines react towards oxidation is of primary importance. Here, a novel approach was developed based on the quantitative determination of the key intermediate H2O2 produced during accelerated oxidation by ambient oxygen. The assay makes use of the conversion of the non-fluorescent Amplex Red substrate into a fluorescent product in presence of H2O2.

Assessment of photosystem II thermoluminescence as a tool to investigate the effects of dehydration and rehydration on the cyclic/chlororespiratory electron pathways in wheat and barley leaves.

Thermoluminescence emission from wheat leaves was recorded under various controlled drought stress conditions: (i) fast dehydration (few hours) of excised leaves in the dark (ii) slow dehydration (several days) obtained by withholding watering of plants under a day/night cycle (iii) overnight rehydration of the slowly dehydrated plants at a stage of severe dessication. In fast dehydrated leaves, the AG band intensity was unchanged but its position was shifted to lower temperatures, indicating an activation of cyclic and chlororespiratory pathways in darkness, without any increase of their overall electron transfer capacity. By contrast, after a slow dehydration the AG intensity was strongly increased whereas its position was almost unchanged, indicating respectively that the capacity of cyclic pathways was enhanced but that they remained inactivated in darkness.

Pitfalls, artefacts and open questions in chlorophyll thermoluminescence of leaves or algal cells.

Thermoluminescence of intact photosynthetic organisms, leaves or algal cells, raises specific problems. The constitutive S2/3Q B (-) B bands constitute major probes of the state of photosystem II in vivo. The presence of a dark-stable acidic lumen causes a temperature downshift of B bands, specially the S3 B band, providing a lumen pH indicator.

Thermoluminescence and P700 redox kinetics as complementary tools to investigate the cyclic/chlororespiratory electron pathways in stress conditions in barley leaves.

Cyclic electron flow around photosystem I drives additional proton pumping into the thylakoid lumen, which enhances the protective non-photochemical quenching and increases ATP synthesis. It involves several pathways activated independently. In whole barley leaves, P700 oxidation under far-red illumination and subsequent P700(+) dark reduction kinetics provide a major probe of the activation of cyclic pathways.

Peculiar properties of chlorophyll thermoluminescence emission of autotrophically or mixotrophically grown Chlamydomonas reinhardtii.

The microalgae Chlamydomonas reinhardtii and Chlorella sp. CCAP 211/84 were grown autotrophically and mixotrophically and their thermoluminescence emissions were recorded above 0 °C after excitation by 1, 2 or 3 xenon flashes or by continuous far-red light. An oscillation of the B band intensity according to the number of flashes was always observed, with a maximum after 2 flashes, accompanied by a downshift of the B band temperature maximum in mixotrophic compared to autotrophic grown cells, indicative of a dark stable pH gradient.

Thermoluminescence: experimental.

Thermoluminesence measurements are useful for the study of Photosystem II electron transport in intact leaves, in algal and cyanobacterial cells, as well as in isolated membrane complexes. Here an overview of the experimental approaches is provided. In the present review, instruments and the experimental procedures for measuring thermoluminescence emission from photosynthetic systems of various origins are summarized and discussed.

Photosynthesis limitations during water stress acclimation and recovery in the drought-adapted Vitis hybrid Richter-110 (V. berlandierixV. rupestris).

The hybrid Richter-110 (Vitis berlandierixVitis rupestris) has the reputation of being a genotype strongly adapted to drought. A study was performed with plants of R-110 subjected to sustained water-withholding to induce acclimation to two different levels of water stress, followed by rewatering to induce recovery. The goal was to analyse how photosynthesis is regulated during acclimation to water stress and recovery.

[Evaluation of HBA1C measurement on Architect CI8200 (Abbott Diagnostic). Comparison with HPLC D-10 Bio-Rad assay].

The aim of this study is to present an evaluation of HbA(1c) Assay on Architect CI8200 (Abbott Diagnostic). The measurement includes Hb assay by colorimetry and HbA(1c) by immunoturbidimetry. The percentage of HbA(1c) is the report HbA(1c)/complete Hb with a conversion coefficient.

Changes in photosynthetic metabolism induced by tobamovirus infection in Nicotiana benthamiana studied in vivo by thermoluminescence.

* In thylakoids from Nicotiana benthamiana infected with the pepper mild mottle virus (PMMoV), a decreased amount of the PsbP and PsbQ proteins of photosystem II and different proteins of the Calvin cycle have been previously observed. We used thermoluminescence to study the consequences in vivo. * Measurements on unfrozen discs from symptomatic and asymptomatic leaves of plants infected by two tobamovirus PMMoV-S and PMMoV-I strains were compared with homologous samples in control plants.

Chlorophyll thermofluorescence and thermoluminescence as complementary tools for the study of temperature stress in plants.

The photosynthetic apparatus, especially the electron transport chain imbedded in the thylakoid membrane, is one of the main targets of cold and heat stress in plants. Prompt and delayed fluorescence emission originating from photosystem II have been used, most often separately, to monitor the changes induced in the photosynthetic membranes during progressive warming or cooling of a leaf sample. Thermofluorescence of F (0) and F (M) informs on the effects of heat on the chlorophyll antennae and the photochemical centers, thermoluminescence on the stabilization and movements of charges and Delayed Light Emission on the permeability of the thylakoid membranes to protons and ions.

Probing the FQR and NDH activities involved in cyclic electron transport around Photosystem I by the 'afterglow' luminescence.

Far-red illumination of plant leaves for a few seconds induces a delayed luminescence rise, or afterglow, that can be measured with the thermoluminescence technique as a sharp band peaking at around 40-45 degrees C. The afterglow band is attributable to a heat-induced electron flow from the stroma to the plastoquinone pool and the PSII centers. Using various Arabidopsis and tobacco mutants, we show here that the electron fluxes reflected by the afterglow luminescence follow the pathways of cyclic electron transport around PSI.

Role of the oxidized secondary acceptor QB of photosystem II in the delayed 'afterglow' chlorophyll luminescence.

Leaf discs of dark-adapted tobacco plants were excited by 2 flashes and kept in darkness at 20 degrees C for various time periods, then thermoluminescence emission was recorded without freezing the sample. The B band at 30 degrees C decreased with a half-time t1/2 approximately 1 min and the AG band at 45 degrees C with a t1/2 approximately 5 min. This corresponds to the decay kinetics of S2/3 in PS II centres in the state S2/3 QB - (B band) or S2/3 QB.

Cyclic electron flow around PSI monitored by afterglow luminescence in leaves of maize inbred lines (Zea mays L.): correlation with chilling tolerance.

Maize (Zea mays L.) inbred lines of contrasting chilling sensitivity (three tolerant, three sensitive lines) were acclimated to 280 mumol photons m(-2) s(-1) white light at a 17 degrees C sub-optimal temperature. They showed no symptoms of photoinhibition, despite slight changes in photosystem II (PSII) fluorescence and thermoluminescence properties in two tolerant lines.

Cytochrome c550 in the cyanobacterium Thermosynechococcus elongatus: study of redox mutants.

Cytochrome c(550) is one of the extrinsic Photosystem II subunits in cyanobacteria and red algae. To study the possible role of the heme of the cytochrome c(550) we constructed two mutants of Thermosynechococcus elongatus in which the residue His-92, the sixth ligand of the heme, was replaced by a Met or a Cys in order to modify the redox properties of the heme. The H92M and H92C mutations changed the midpoint redox potential of the heme in the isolated cytochrome by +125 mV and -30 mV, respectively, compared with the wild type.

Chlorophyll thermoluminescence of leaf discs: simple instruments and progress in signal interpretation open the way to new ecophysiological indicators.

Luminescence from photosynthetic material observed in darkness following illumination is a delayed fluorescence produced by a recombination of charge pairs stored in photosystem II, i.e. the back-reaction of photosynthetic charge separation.

Biological fluxes conversion and SXRF experiment with a new active biomonitoring tool for atmospheric metals and trace element deposition.

A new active biomonitoring tool, keeping alive mosses for 2 months, had demonstrated the buffering action of the water presence on the biological activity of three moss species (chlorophyll fluorescence induction method on Pleurozium schreberi, Scleropodium purum, Eurhynchium praelongum). The two more resistant mosses were exposed on four different sites with parallel exposure of monthly bulk collectors during three successive periods of 2 months. The coarse and sedimentable particles of bulk collectors were separated into different size classes (> 1 mm; 1000-200 microm; 200-40 microm; 40-20 microm).

Chlorophyll high-temperature thermoluminescence emission as an indicator of oxidative stress: perturbating effects of oxygen and leaf water content.

A high-temperature chlorophyll thermoluminescence emission can be observed in plant leaves, without preillumination, following various oxidative stresses. This emission was recorded from 0 degrees C to 160 degrees C on a leaf sample pressed by a teflon ring on a heating plate. A band at 140 degrees C was observed in senescing tree leaves, a band at 130 degrees C with a shoulder at 75 degrees C in tobacco leaves treated with the fungal elicitor cryptogein.

Heat stress induces in leaves an increase of the minimum level of chlorophyll fluorescence, Fo: A time-resolved analysis.

A time-resolved study of the effects of heat stress (23 to 50°C) on Fo level of chlorophyll fluorescence of leaves having different antenna content has been performed in order to elucidate the causes of heat induced increase of Fo in vivo. The multi-exponential deconvolution of the decays after a picosecond flash at Fo have shown that the best fit in both wild-type and the mutant chlorina F2 of barley leaves is obtained with three components in the temperature range utilized (100, 400 and 1200 ps at 23°C). In intermittent light greened pea leaves, a fourth long lifetime component (4 ns at 23°C) is needed.

Effects of dark- and light-induced proton gradients in thylakoids on the Q and B thermoluminescence bands.

Thermoluminescence experiments have been carried out to study the effect of a transmembrane proton gradient on the recombination properties of the S2 and S3 states of the oxygen evolving complex with QA (-) and QB (-), the reduced electron acceptors of Photosystem II. We first determined the properties of the S2QA (-) (Q band), S2QB (-) and S3QB (-) (B bands) recombinations in the pH range 5.5 to 9.

A Mutation in the D-de Loop of D1 Modifies the Stability of the S2QA- and S2QB- States in Photosystem II.

Photosystem II electron transfer, charge stabilization, and photoinhibition were studied in three site-specific mutants of the D1 polypeptide of Synechocystis PCC 6803: E243K, E229D, and CA1 (deletion of three glutamates 242-244 and a substitution, glutamine-241 to histidine). The phenotypes of the E229D and E243K mutants were similar to that of the control strain (AR) in all of the studied aspects. The characteristics of CA1 were very different.

Graphical and numerical analysis of thermoluminescence and fluorescence F0 emission in photosynthetic material.

A set-up for recording thermoluminescence emission together with the constant F0 fluorescence yield is described briefly. It is driven by a microcomputer through plugged-in cards.Practical aspects of the simulation of TL bands and of decomposition of complex TL signals are examined.

Oxygen-evolving photosystem II preparation from wild type and photosystem II mutants of Synechocystis sp. PCC 6803.

We present here a simple and rapid method which allows relatively large quantities of oxygen-evolving photosystem II- (PS-II-) enriched particles to be obtained from wild-type and mutants of the cyanobacterium Synechocystis 6803. This method is based on that of Burnap et al. [Burnap, R.