scholarly journals Effect of recombinant phycocyanin on photosynthetic system in Chlamydomonas reinhardtii

2019 ◽  
Author(s):  
Feng Zhang ◽  
Xiaomei Cong ◽  
Zhendong Wang ◽  
Yalin Guo ◽  
Lulu Hou ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Fluorescence Emission ◽  
Arthrospira Platensis ◽  
Transcriptional Level ◽  
Light Conditions ◽  
Low Light ◽  
Fluorescence Emission Spectra ◽  
Photosynthetic System ◽  
Ferredoxin Oxidoreductase ◽  
Transgenic Strains

AbstractThe phycobilisome is an important photosynthetic antenna in the photosynthetic cyanobacteria, and phycocyanin is one of the main components of phycobilisomes. It helps cells absorb green light that green-lineage photo-synthetic organisms cannot. In this work, phycocyanin, heme oxidase and ferredoxin oxidoreductase from Arthrospira platensis FACHB 314 were successfully expressed in the green algae Chlamydomonas reinhardtii. Then the effects of this expression on the photosynthesis and growth of C. reinhardtii were detected. Transcriptional level analysis showed that the phycocyanin gene was successfully expressed stably in the transgenic strains. The results of low-temperature fluorescence emission spectra and chlorophyll fluorescence showed that recombinant phycocyanin has considerable optical activity. The expression of phycocyanin, heme oxidase and ferredoxin oxidoreductase in low-light conditions is particularly evident in the promotion of photosynthesis in C. reinhardtii. The growth of transgenic strains was significantly promoted in the early growth phase under low-light conditions. However, the final growth and biomass accumulation of transgenic C. reinhardti were inhibited by this expression. In this paper, the possibility of photoenergy transfer between phycocyanin and heterologous host thylakoid membrane was researched, which provided a useful attempt for the construction of a new photosynthetic system using phycobiliprotein from cyanobacteria.One-sentence summaryPhycocyanin from Arthrospira platensis FACHB 314 expressed in Chlamydomonas reinhardtii can effect the photosynthetic system of C. reinhardtii.

scholarly journals Stability of Chlorophyll a Monomer Incorporated into Cremophor EL Nano-Micelles under Dark and Moderate Light Conditions

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5059
Author(s):  
Ewa Janik-Zabrotowicz ◽  
Marta Arczewska ◽  
Patrycja Prochniewicz ◽  
Izabela Świetlicka ◽  
Konrad Terpiłowski
Keyword(s):  
Chlorophyll A ◽  
Self Assembly ◽  
Molecular Spectroscopy ◽  
Fluorescence Emission ◽  
Molecular Organization ◽  
Cremophor El ◽  
Light Conditions ◽  
Fluorescence Emission Spectra ◽  
Pigment Stability ◽  
The Stability

In this paper, stability of chlorophyll a monomers encapsulated into the Cremophor EL nano-micelles was studied under dark and moderate light conditions, typical of a room with natural or artificial lighting, in the presence of oxygen. The pigment stability against visible light was determined using the dynamic light scattering and molecular spectroscopy (UV-Vis absorption and stationary fluorescence) methods. Chlorophyll a, at the molar concentration of 10−5 M, was dissolved in the 5 wt% Cremophor emulsion for comparison in the ethanolic solution. The stability of such a self-assembly pigment–detergent nano-system is important in the light of its application on the commercial-scale. The presented results indicate the high stability of the pigment monomeric molecular organization in the nano-emulsion. During the storage in the dark, the half-lifetime was calculated as about 7 months. Additionally, based on the shape of absorption and fluorescence emission spectra, chlorophyll aggregation in the Cremophor EL aqueous solution along with the time was excluded. Moreover, the average size of detergent micelles as chlorophyll carriers was not affected after 70 days of the nano-system storage. Pigment stability against the moderate white light (0.1 mW) did not differ significantly from storage conditions in the dark. The photooxidation products, detected by occurrence of new absorption and fluorescence emission bands, was estimated on the negligible level. The stability of such a self-assembly pigment–detergent nano-system would potentially broaden the field of chlorophyll a (chl a) application in the food industry, medicine or artificial photosynthesis models.

Changes in the Stoichiometry of Photosystem II Components as an Adaptive Response to High-Light and Low-Light Conditions during Growth

1986 ◽  
Vol 41 (5-6) ◽  
pp. 597-603 ◽  
Author(s):  
Aloysius Wild ◽  
Matthias Höpfner ◽  
Wolfgang Rühle ◽  
Michael Richter
Keyword(s):  
Photosystem Ii ◽  
Functional Organization ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Molar Ratio ◽  
Light Conditions ◽  
Low Light ◽  
Pigment System ◽  
Transport Chain ◽  
The One

The effect of different growth light intensities (60 W·m-2, 6 W·m-2) on the performance of the photosynthetic apparatus of mustard plants (Sinapis alba L.) was studied. A distinct decrease in photosystem II content per chlorophyll under low-light conditions compared to high-light conditions was found. For P-680 as well as for Oᴀ and Oв protein the molar ratio between high-light and low-light plants was 1.4 whereas the respective concentrations per chlorophyll showed some variations for P-680 and Oᴀ on the one and Oв protein on the other hand.In addition to the study of photosystem II components, the concentrations of PQ, Cyt f, and P-700 were measured. The light regime during growth had no effect on the amount of P-700 per chlorophyll but there were large differences with respect to PQ and Cyt f. The molar ratio for Cyt f and PQ between high- and low-light leaves was 2.2 and 1.9, respectively.Two models are proposed, showing the functional organization of the pigment system and the electron transport chain in thylakoids of high-light and low-light leaves of mustard plants.

Optical Properties and Zinc Nitride Thin Films Prepared Using Magnetron Reactive Sputtering

2014 ◽  
Vol 940 ◽  
pp. 11-15
Author(s):  
Jun Qin Feng ◽  
Jun Fang Chen
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Sem Images ◽  
Fluorescence Emission Spectra ◽  
Glass Substrates ◽  
Zinc Nitride ◽  
Direct Band

Zinc nitride films were deposited by ion sources-assisted magnetron sputtering with the use of Zn target (99.99% purity) on 7059 glass substrates. The films were characterized by XRD, SEM and EDS, the results of which show that the polycrystalline zinc nitride thin film can be grown on the glass substrates, the EDS spectrum confirmed the chemical composition of the films and the SEM images revealed that the zinc nitride thin films have a dense structure. Ultraviolet-visible-near infrared spectrophotometer was used to study the transmittance behaviors of zinc nitride thin films, which calculated the optical band gap by Davis Mott model. The results of the fluorescence emission spectra show the zinc nitride would be a direct band gap semiconductor material.

scholarly journals Perceptually based tone mapping for low-light conditions

2011 ◽  
Author(s):  
Adam G. Kirk ◽  
James F. O'Brien
Keyword(s):  
Tone Mapping ◽  
Light Conditions ◽  
Low Light

scholarly journals Perceptually based tone mapping for low-light conditions

2011 ◽  
Vol 30 (4) ◽  
pp. 1-10 ◽  
Author(s):  
Adam G. Kirk ◽  
James F. O'Brien
Keyword(s):  
Tone Mapping ◽  
Light Conditions ◽  
Low Light

Stress and Phase Transformation Phenomena in Oxide Films: Real-Time Spectroscopic Measurements

1992 ◽  
Vol 271 ◽  
Author(s):  
Gregory J. Exarhos ◽  
Nancy J. Hess
Keyword(s):  
Phase Transformation ◽  
Applied Pressure ◽  
Oxide Films ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Film Deposition ◽  
Optical Methods ◽  
Fluorescence Emission Spectra ◽  
Line Intensities ◽  
Deposition Parameters

ABSTRACTIn situ optical methods are reviewed for characterization of phase transformation processes and evaluation of residual stress in solution-deposited metastable oxide films. Such low density films most often are deposited as disordered phases making them prone to crystallization and attendant densification when subjected to increased temperature and/or applied pressure. Inherent stress imparted during film deposition and its evolution during the transformation are evaluated from phonon frequency shifts seen in Raman spectra (TiO2) or from changes in the laser-induced fluorescence emission spectra for films containing rare earth (Sm+3:Y3Al5O12) or transition metal (Cr+3 :Al2O3) dopants. The data in combination with measured increases in line intensities intrinsic to the evolving phase are used to follow crystallization processes in thin films. In general, film deposition parameters are found to influence the crystallite ingrowth kinetics and the magnitude of stress and stress relaxation in the film during the transformation. The utility of these methods to probe crystallization phenomena in oxide films will be addressed.

scholarly journals Olfactory acuity in theropods: palaeobiological and evolutionary implications

2008 ◽  
Vol 276 (1657) ◽  
pp. 667-673 ◽  
Author(s):  
Darla K Zelenitsky ◽  
François Therrien ◽  
Yoshitsugu Kobayashi
Keyword(s):  
Olfactory Bulb ◽  
Cerebral Hemisphere ◽  
Home Ranges ◽  
Light Conditions ◽  
Low Light ◽  
Olfactory Bulbs ◽  
Theropod Dinosaurs ◽  
Olfactory Acuity ◽  
Predicted Values ◽  
Omnivorous Diet

This research presents the first quantitative evaluation of the olfactory acuity in extinct theropod dinosaurs. Olfactory ratios (i.e. the ratio of the greatest diameter of the olfactory bulb to the greatest diameter of the cerebral hemisphere) are analysed in order to infer the olfactory acuity and behavioural traits in theropods, as well as to identify phylogenetic trends in olfaction within Theropoda. A phylogenetically corrected regression of olfactory ratio to body mass reveals that, relative to predicted values, the olfactory bulbs of (i) tyrannosaurids and dromaeosaurids are significantly larger, (ii) ornithomimosaurs and oviraptorids are significantly smaller, and (iii) ceratosaurians, allosauroids, basal tyrannosauroids, troodontids and basal birds are within the 95% CI. Relative to other theropods, olfactory acuity was high in tyrannosaurids and dromaeosaurids and therefore olfaction would have played an important role in their ecology, possibly for activities in low-light conditions, locating food, or for navigation within large home ranges. Olfactory acuity was the lowest in ornithomimosaurs and oviraptorids, suggesting a reduced reliance on olfaction and perhaps an omnivorous diet in these theropods. Phylogenetic trends in olfaction among theropods reveal that olfactory acuity did not decrease in the ancestry of birds, as troodontids, dromaeosaurids and primitive birds possessed typical or high olfactory acuity. Thus, the sense of smell must have remained important in primitive birds and its presumed decrease associated with the increased importance of sight did not occur until later among more derived birds.

scholarly journals Fluorescence emission spectra of silver and silver/cobalt nanoparticles

2012 ◽  
Vol 19 (3) ◽  
pp. 943-947 ◽  
Author(s):  
Z. Parang ◽  
A. Keshavarz ◽  
S. Farahi ◽  
S.M. Elahi ◽  
M. Ghoranneviss ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
Emission Spectra ◽  
Cobalt Nanoparticles ◽  
Fluorescence Emission Spectra
Sign in / Sign up

Export Citation Format

Share Document