Dark Anaerobic Conditions Induce a Fast Induction of the Xanthophyll Cycle in When Exposed to High Light.

Background: Dark anaerobiosis promotes the acidification of the thylakoid lumen and a reduction in the plastoquinone (PQ) pool. The relationship between the reduction in the PQ pool in the dark and the induction of the xanthophyll cycle under high light stress was investigated in .

Methods: To achieve a comprehensive oxidative/reductive (aerobic/anaerobic conditions) state of the PQ pool, cultures were bubbled with air or nitrogen for 4 h.

Fire up Biosensor Technology to Assess the Vitality of Trees after Wildfires.

The development of tools to quickly identify the fate of damaged trees after a stress event such as a wildfire is of great importance. In this context, an innovative approach to assess irreversible physiological damage in trees could help to support the planning of management decisions for disturbed sites to restore biodiversity, protect the environment and understand the adaptations of ecosystem functionality. The vitality of trees can be estimated by several physiological indicators, such as cambium activity and the amount of starch and soluble sugars, while the accumulation of ethanol in the cambial cells and phloem is considered an alarm sign of cell death.

Photosynthesis and biochemical characterization of the green alga Chlamydopodium fusiforme (Chlorophyta) grown in a thin-layer cascade.

Photosynthesis, growth and biochemical composition of the biomass of the freshwater microalga Chlamydopodium fusiforme cultures outdoors in a thin-layer cascade were investigated. Gross oxygen production measured off-line in samples taken from the outdoor cultures was correlated with the electron transport rate estimated from chlorophyll a fluorescence measurements. According to photosynthesis measurements, a mean of 38.

Growth and photosynthetic performance of Nostoc linckia (formerly N. calcicola) cells grown in BG11 and BG11 media.

The biotechnological potential of Nostoc linckia as a biofertilizer and source of bioactive compounds makes it important to study its growth physiology and productivity. Since nitrogen is a fundamental component of N. linckia biomass, we compared the growth and biochemical composition of cultures grown in BG11 (i.

Investigation of Photosystem II Functional Size in Higher Plants under Physiological and Stress Conditions Using Radiation Target Analysis and Sucrose Gradient Ultracentrifugation.

The photosystem II (PSII) reaction centre is the critical supramolecular pigment-protein complex in the chloroplast which catalyses the light-induced transfer of electrons from water to plastoquinone. Structural studies have demonstrated the existence of an oligomeric PSII. We carried out radiation inactivation target analysis (RTA), together with sucrose gradient ultracentrifugation (SGU) of PSII, to study the functional size of PSII in diverse plant species under physiological and stress conditions.

Purple non-sulfur bacteria as cell factories to produce a copolymer as PHBV under light/dark cycle in a 4-L photobioreactor.

The present study reports a strategy to produce polyhydroxyalkanoates (PHAs) by culturing the marine bacterium Rhodovulum sulfidophilum DSM-1374. The study was carried out by growing the bacterium anaerobically for 720 h under 16/8 light/dark cycle. Two analytical techniques such as proton magnetic nuclear magnetic resonance (H NMR) and Fourier transform infrared spectroscopy (FT-IR) were used to determine that the polyester produced was poly-3-hydroxybutirate-co-3-hydroxyvalerate (PHBV).

Effect of plate distance on light conversion efficiency of a Synechocystis culture grown outdoors in a multiplate photobioreactor.

In this work, the performance of a vertical multiplate photobioreactor is analyzed and presented. The photobioreactor consisted of 20 vertical plates (1 m each) connected by manifolds and a working volume of 1300 L. The total area occupied (footprint) was 10 m, while the illuminated area was 40 m, therefore the ratio of illuminated area to volume ratio was about 30 m.

In situ monitoring of chlorophyll a fluorescence in Nannochloropsis oceanica cultures to assess photochemical changes and the onset of lipid accumulation during nitrogen deprivation.

In situ chlorophyll a fluorescence measurements were applied to monitor changes in the photochemical variables of Nannochloropsis oceanica cultures under nitrogen-deplete and nitrogen-replete (control) conditions. In addition, growth, lipid, fatty acid, and pigment contents were also followed. In the control culture, growth was promoted along with pigment content, electron transport rate (ETR), and polyunsaturated fatty acids, while total lipid content and fatty acid saturation level diminished.

Photoautotrophs-Bacteria Co-Cultures: Advances, Challenges and Applications.

Photosynthetic microorganisms are among the fundamental living organisms exploited for millennia in many industrial applications, including the food chain, thanks to their adaptable behavior and intrinsic proprieties. The great multipotency of these photoautotroph microorganisms has been described through their attitude to become biofarm for the production of value-added compounds to develop functional foods and personalized drugs. Furthermore, such biological systems demonstrated their potential for green energy production (e.

Bioplastic production by feeding the marine Rhodovulum sulfidophilum DSM-1374 with four different carbon sources under batch, fed-batch and semi-continuous growth regimes.

In the present study, the ability of the marine bacterium Rhodovulum sulfidophilum DSM-1374 to convert, via photo-fermentative process, certain organic acids such as single carbon source (acetate, lactate, malate and succinate) into polyhydroxyalkanoate accumulations within bacterial cells is evaluated. The main goal of the investigation was poly-3-hydroxybutyrate (P3HB) synthesis by a photo-fermentative process. Of the four carbon sources, only succinate simultaneously produced P3HB and H (268 mg/L and 1085 mL/L respectively).

Production of Biohydrogen and/or Poly-β-hydroxybutyrate by Rhodopseudomonas sp. Using Various Carbon Sources as Substrate.

The polyhydroxyalkanoates (PHA) are family of biopolyesters synthesized by numerous bacteria which are attracting a great attention due to their thermoplastic properties. Polyhydroxybutyrate (PHB) is the most common type of PHA which presents thermoplastic and biodegradable properties. It is synthesized under stressful conditions by heterotrophic bacteria and many photosynthetic microorganisms such as purple non-sulfur bacteria and cyanobacteria.

Whey and molasses as inexpensive raw materials for parallel production of biohydrogen and polyesters via a two-stage bioprocess: New routes towards a circular bioeconomy.

Consecutive dark-fermentation and photo-fermentation stages were investigated for a profitable circular bio-economy. H photo-production versus poly(3-hydroxybutyrate) (P3HB) accumulation is a modern biotechnological approach to use agro-food industrial byproducts as no-cost rich-nutrient medium in eco-sustainable biological processes. Whey and molasses are very important byproducts rich in nutrients that lactic acid bacteria can convert, by dark-fermentation, in dark fermented effluents of whey (DFE) and molasses (DFE).

Poly-3-hydroxybutyrate and H production by Rhodopseudomonas sp. S16-VOGS3 grown in a new generation photobioreactor under single or combined nutrient deficiency.

The main goal of this investigation was setting up a growth strategy to separate H evolution from P3HB synthesis in order to increase cumulative P3HB in Rhodopseudomonas cells. The accumulation of poly-3-hydroxybutyrate (P3HB) was investigated culturing Rhodopseudomonas sp. S16-VOGS3 with three carbon substrates either as acetate, butyrate or lactate and with two nitrogen sources either as ammonium or glutamate.

Effect of high pH on growth of Synechocystis sp. PCC 6803 cultures and their contamination by golden algae (Poterioochromonas sp.).

Culturing cyanobacteria in a highly alkaline environment is a possible strategy for controlling contamination by other organisms. Synechocystis PCC 6803 cells were grown in continuous cultures to assess their growth performance at different pH values. Light conversion efficiency linearly decreased with the increase in pH and ranged between 12.

A bioenergetic assessment of photosynthetic growth of Synechocystis sp. PCC 6803 in continuous cultures.

Background: Synechocystis sp. PCC 6803, a model organism used for bioenergy and bioplastic production, was grown in continuous culture to assess its most important bioenergetic parameters.

Results: Biomass yield on light energy of 1.

Preventive or potential therapeutic value of nutraceuticals against ionizing radiation-induced oxidative stress in exposed subjects and frequent fliers.

Humans are constantly exposed to ionizing radiation deriving from outer space sources or activities related to medical care. Absorption of ionizing radiation doses over a prolonged period of time can result in oxidative damage and cellular dysfunction inducing several diseases, especially in ageing subjects. In this report, we analyze the effects of ionizing radiation, particularly at low doses, in relation to a variety of human pathologies, including cancer, and cardiovascular and retinal diseases.

A photosynthetic biosensor with enhanced electron transfer generation realized by laser printing technology.

One of the limits of current electrochemical biosensors is a lack of methods providing stable and highly efficient junctions between biomaterial and solid-state devices. This paper shows how laser-induced forward transfer (LIFT) can enable efficient electron transfer from photosynthetic biomaterial immobilized on screen-printed electrodes (SPE). The ideal pattern, in terms of photocurrent signal of thylakoid droplets giving a stable response signal with a current intensity of approximately 335 ± 13 nA for a thylakoid mass of 28 ± 4 ng, was selected.

Intercalation of the herbicide atrazine in layered double hydroxides for controlled-release applications.

Background: The herbicide atrazine was intercalated in the interlayer region of Mg/Al layered double hydroxides in order to produce a nanohybrid that could be used in controlled-release applications.

Results: The hydrophobic herbicide was incorporated in artificial membranes formed in the interlayer of the inorganic host by using palmitic acid. The synthetic nanohybrid material was characterised by various techniques, and release studies were carried out.

Nutraceutical use of garlic sulfur-containing compounds.

Garlic is one of the world's oldest medicines that has been employed not only for flavouring but also as a medical herb for its prophylactic and therapeutic actions. Most garlics' beneficial effects are due to the presence of the organosulphate molecule allicin. Allicin is a highly unstable molecule and, during processing, is rapidly transformed into a variety of organosulfur components.

Development of a photosystem II-based optical microfluidic sensor for herbicide detection.

Herbicides are highly toxic for both human and animal health. The increased application of herbicides in agriculture during the last decades has resulted in the contamination of both soil and water. Herbicides, under illumination, can inhibit photosystem II electron transfer.

Isolation, characterization, sequencing and crystal structure of charybdin, a type 1 ribosome-inactivating protein from Charybdis maritima agg.

A novel, type 1 ribosome-inactivating protein designated charybdin was isolated from bulbs of Charybdis maritima agg. The protein, consisting of a single polypeptide chain with a molecular mass of 29 kDa, inhibited translation in rabbit reticulocytes with an IC50 of 27.2 nm.

Role of the PSII-H subunit in photoprotection: novel aspects of D1 turnover in Synechocystis 6803.

Photosystem I-less Synechocystis 6803 mutants carrying modified PsbH proteins, derived from different combinations of wild-type cyanobacterial and maize genes, were constructed. The mutants were analyzed in order to determine the relative importance of the intra- and extramembrane domains of the PsbH subunit in the functioning of photosystem (PS) II, by a combination of biochemical, biophysical, and physiological approaches. The results confirmed and extended previously published data showing that, besides D1, the whole PsbH protein is necessary to determine the correct structure of a QB/herbicide-binding site.