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Covina, CA, United States

Theoretical modelling is often overlooked in photosynthesis research even if it can significantly help with understanding of explored system. A new model of light-induced photosynthetic reactions occurring in and around thylakoid membrane is introduced here and used for theoretical modelling of not only the light-induced chlorophyll (Chl) a fluorescence rise (FLR; the O-J-I-P transient), reflecting function of photosystem II (PSII), but also of the 820 nmtransmittance signal (I 820), reflecting function of photosystem I (PSI) and plastocyanin (PC), paralleling the FLR. Correctness of the model was verified by successful simulations of the FLR and I 820 signal as measured with the control (no treatment) sample but also as measured with 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone- (inhibits electron transport in cytochrome b 6/f) and methylviologen- (accepts electrons from iron-sulphur cluster of PSI) treated samples and with the control sample upon different intensities of excitation light. From the simulations performed for the control sample, contribution of the oxidised donor of PSI, P700, and oxidised PC to the I 820 signal minimum (reflects maximal accumulations of the two components) was estimated to be 75% and 25%, respectively. Further in silico experiments showed that PC must be reduced in the dark, cyclic electron transport around PSI must be considered in the model and activation of ferredoxin-NADP +-oxidoreductase (FNR) also affects the FLR. Correct simulations of the FLR and I 820 signal demonstrate robustness of the model, confirm that the electron transport reactions occurring beyond PSII affect the shape of the FLR, and show usefulness and perspective of theoretical approach in studying of the light-induced photosynthetic reactions. © Springer Science+Business Media B.V. 2010. Source

Sukacova K.,Academy of Sciences of the Czech Republic | Trtilek M.,Photon Systems | Rataj T.,Academy of Sciences of the Czech Republic
Water Research

Eutrophication of surface water has been an important environmental issue for nearly half a century. High concentrations of phosphorus contribute to the process of eutrophication, resulting in the demand for effective and economic methods of phosphorus removal from treated water. The aim of this study was to evaluate the capacity for phosphorus removal of a microalgal biofilm during different light regimes. The photobioreactor was operated for nine months each year over a two-year period without interruption and without any need of re-inoculation. The algal biofilm was able to remove 97±1% of total phosphorus from wastewater during 24hof continuous artificial illumination. The average TP uptake rate in our experiments was 0.16±0.008gm-2d-1. Phosphorus removal values ranged from 36 to 41% when the algal biofilm was illuminated by natural light (12hsunlight-12hnight). The biomass production rate was 12.21±10gdry weightm-2d-1 in experiments with continuous artificial light and 5.6±1g dry weight (DW)m-2d-1 in experiments with natural light. These results indicate the great potential of microalgal biofilms in the tertiary treatment of wastewater. © 2015 Elsevier Ltd. Source

Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 124.07K | Year: 2015

This proposal addresses the need for advanced analytical methods and instrumentation to detect trace levels of chemical and biological contaminants directly on spacecraft and related surfaces to comply with Contamination Control and Planetary Protection requirements in an effort to preserve sample science integrity for life detection investigations on Europa, Enceladus, Mars, etc. The proposed methods employ non-contact deep UV Raman and fluorescence chemical imaging and mapping methods to avoid the need for any contact with spacecraft and related surfaces. The method eliminates the use of traditional sample collection methods such as swabs, wipes, or other methods, which have been shown to back-contaminate spacecraft surfaces as well as collected samples. Raman and fluorescence spectroscopy with excitation in the deep UV below 250 nm enables separation of the spectral regions of both Raman and fluorescence emissions, enabling collection of Raman emissions without obscuration by fluorescence from chemicals of interest as well as many spacecraft materials and from trace organic contamination within field of view of the Raman detection optics. This cannot be accomplished with excitation at longer wavelength including 263 nm or 266 nm from 4th harmonic Nd based lasers. Combining Raman and fluorescence methods in the deep UV enhances the ability to detect and identify the trace chemical or biological materials on these surfaces and have a proven ability to detect biological and other particles and materials on surfaces less than 1 pg, the mass of a single bacterial spore, with dimensions as small as 200 nm. These methods were first developed under funding from NASA Planetary Protection, but were advanced by contracts with several Department of Defense organizations well as commercial developments with both Pfizer Pharmaceutical and DuPont for chemical and biological cleaning validation of their manufacturing equipment.

Agency: Department of Defense | Branch: Army | Program: STTR | Phase: Phase II | Award Amount: 749.85K | Year: 2011

This proposal addresses the need to increase the probability of detection (PD) and reduce the probability of false alarm (Pfa) for non-contact, real-time sensors for trace levels of biological and chemical targets using simultaneous detection of Raman and fluorescence emissions. Raman spectroscopy is a spectroscopic method that provides information about molecular bonds in target materials. Fluorescence spectroscopy is a much more sensitive spectroscopic method that provides information regarding the electronic configuration of target molecules. Photon Systems has been developing combined Raman and fluorescence methods for over 6 years with a focus on the advantages of excitation in the deep UV below 250nm. There are three main advantages of excitation in the deep UV, below 250nm compared to near-UV, visible or near-IR counterparts. 1) Raman scattering occurs in a fluorescence-free region of the spectrum. At longer excitation wavelengths, fluorescence from target or surrounding materials overwhelms weak Raman emissions, making them impossible to detect. 2) The wavelength range for Raman and fluorescence emissions is separate, enabling simultaneous detection of both modes of emission. 3) Resonance Raman occurs for a wide range of biological and organic materials, providing simplified and more easily interpreted Raman spectra as well as enabling enhanced Raman signal strength."

Agency: Cordis | Branch: FP7 | Program: BSG-SME | Phase: SME-1 | Award Amount: 1.50M | Year: 2011

In August 2009 was fully implemented the reform of the Common Market Organization for wine (CR N479/2008, 29-04-2008). It aims at reducing the 24 million hl/year surplus of basic low quality wine, phasing out the 500 million/year spent on wine disposal subsidies and making EU wine more competitive. This reform, together with other market constraints will endanger all EU winegrowing SMEs. To survive, they will have to increase crop value, reduce the production of basic wine and convert part into premium quality. This can be achieved by implementing new and more effective field control methods. PREMIVM proposes a low-cost, handheld device capable of non-invasively estimating ripeness and vigour parameters for grapes and vine plants. All this in the vineyard, by means of the innovative use of chlorophyll fluorescence and reflectance multispectral data correlated by specific mathematical models, with GPS tags for all readings. The device will provide data to precisely control the field, and increase production value up to 25% (expected yearly 5.000-10.000/ha income increase for winegrowing SMEs like PEREZ, QMF and PERACCIO). With a cost of 2500/ unit, consortium manufacture and distribution SMEs PSI and AGRI estimate, through a joint-venture, to reach at least 2% of the market in 5 years. This is equivalent to an expected income of 70 million, with a 30 million profit and a ROI of 0.86. The consortium provides the complementary business capabilities, commercial networks and research expertise to guarantee the technology a quick route to the market. All members are fully committed to ensuring the success of the project, led by the SMEs in testing, validating, using and protecting the results outsourced to the necessary expertise in Chl-F&R, optical instrumentation, botany, IT solutions, communications and prototyping of RTDs BIOENG, KIT and ISBE.

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