Light regulating metabolic responses of Cyanobium sp. (Cyanobacteria)

2020 ◽  
Vol 193 (4) ◽  
pp. 285-297 ◽  
Author(s):  
Fernando Pagels ◽  
José Bonomi Barufi ◽  
Julia Vega ◽  
Roberto Abdala-Díaz ◽  
Vitor Vasconcelos ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Photosynthetic Activity ◽  
Processing Parameters ◽  
Light Sources ◽  
Light Conditions ◽  
Light Irradiance ◽  
Important Group ◽  
Bg11 Medium ◽  
P Concentration ◽  
Sodium Lamp

Cyanobacteria are an important group of microorganisms of significant economic interest due to, for ex- ample, the antioxidant capacity of their metabolites. Cyanobium sp. LEGE 06113 is a marine cyanobacterium poorly studied, but with promising future applications. The aim of this study was to optimize the light conditions (both source and irradiance) and nutrient (N and P) concentration for Cyanobium sp. production as a source of high-valued com- pounds. The optimization of the processing parameters was performed using two different light sources (fluorescent and low-pressure sodium lamp), four irradiances (50, 100, 200 and 300 μmol photons m–2 s–1) and two variations of BG11 medium (BG11 and BG11+, with the second containing double amounts of phosphates and nitrates). The effects of the three factors were evaluated on the biomass production, photosynthetic activity, biochemical composition and antioxidant capacity. A synergistic effect between the light source, light intensity, and medium was observed for all measured parameters, with the greatest impact of light irradiance on the metabolism of Cyanobium sp. The combination of the SOX lamp, BG11+ medium, and a light irradiance of 200 μmol photons m–2 s–1 was optimal for the cultivation of Cyanobium sp. This work reports the tools for the production of Cyanobium sp. as a source of high-value products, thus increasing its biotechnological potentials.

The Research on the Application of Two Kinds of Light Sources in the Training Venue for Physical Education of Universities

2012 ◽  
Vol 430-432 ◽  
pp. 1786-1790 ◽  
Author(s):  
Shu Fang Li
Keyword(s):  
Energy Efficiency ◽  
High Pressure ◽  
Physical Education ◽  
Lighting Design ◽  
Light Sources ◽  
Metal Halide Lamp ◽  
Sodium Lamp ◽  
Electric Light ◽  
High Pressure Sodium Lamp ◽  
Power And Energy

The energy efficiency experiment of electric light is implemented according to the lighting design of the physical training venues. In the experiment, the corresponding illumination, power and energy efficiency ratio of the commonly used high pressure sodium lamp and metal halide lamp which work under the voltage ranging from 187V to 234V are experimentally measured and the lighting effect characteristics of the two kinds of electric light sources compared, proving that the high pressure sodium light source should be employed in the training venue for physical education of universities.

scholarly journals Automated Microscopy: Macro Language Controlling a Confocal Microscope and its External Illumination: Adaptation for Photosynthetic Organisms

2016 ◽  
Vol 22 (2) ◽  
pp. 258-263 ◽  
Author(s):  
Gábor Steinbach ◽  
Radek Kaňa
Keyword(s):  
Light Sources ◽  
Light Conditions ◽  
Photosynthetic Organisms ◽  
Automated Microscopy ◽  
Photosynthetic Microorganisms ◽  
Arduino Microcontroller ◽  
Microscopy Data ◽  
Kinetics Of ◽  
Photosynthetic Cells

AbstractPhotosynthesis research employs several biophysical methods, including the detection of fluorescence. Even though fluorescence is a key method to detect photosynthetic efficiency, it has not been applied/adapted to single-cell confocal microscopy measurements to examine photosynthetic microorganisms. Experiments with photosynthetic cells may require automation to perform a large number of measurements with different parameters, especially concerning light conditions. However, commercial microscopes support custom protocols (throughTime Controlleroffered by Olympus orExperiment Designeroffered by Zeiss) that are often unable to provide special set-ups and connection to external devices (e.g., for irradiation). Our new system combining an Arduino microcontroller with theCell⊕Findersoftware was developed for controlling Olympus FV1000 and FV1200 confocal microscopes and the attached hardware modules. Our software/hardware solution offers (1) a text file-based macro language to control the imaging functions of the microscope; (2) programmable control of several external hardware devices (light sources, thermal controllers, actuators) during imaging via the Arduino microcontroller; (3) theCell⊕Findersoftware with ergonomic user environment, a fast selection method for the biologically important cells and precise positioning feature that reduces unwanted bleaching of the cells by the scanning laser.Cell⊕Findercan be downloaded fromhttp://www.alga.cz/cellfinder. The system was applied to study changes in fluorescence intensity inSynechocystissp. PCC6803 cells under long-term illumination. Thus, we were able to describe the kinetics of phycobilisome decoupling. Microscopy data showed that phycobilisome decoupling appears slowly after long-term (>1 h) exposure to high light.

scholarly journals Generalized receptor law governs phototaxis in the phytoplanktonEuglena gracilis

2015 ◽  
Vol 112 (22) ◽  
pp. 7045-7050 ◽  
Author(s):  
Andrea Giometto ◽  
Florian Altermatt ◽  
Amos Maritan ◽  
Roman Stocker ◽  
Andrea Rinaldo
Keyword(s):  
Algal Blooms ◽  
Nonlinear Response ◽  
Temporal Dynamics ◽  
Freshwater Ecosystems ◽  
Trophic Levels ◽  
Light Fields ◽  
Light Sources ◽  
Mathematical Framework ◽  
Heterogeneous Environments ◽  
Light Conditions

Phototaxis, the process through which motile organisms direct their swimming toward or away from light, is implicated in key ecological phenomena (including algal blooms and diel vertical migration) that shape the distribution, diversity, and productivity of phytoplankton and thus energy transfer to higher trophic levels in aquatic ecosystems. Phototaxis also finds important applications in biofuel reactors and microbiopropellers and is argued to serve as a benchmark for the study of biological invasions in heterogeneous environments owing to the ease of generating stochastic light fields. Despite its ecological and technological relevance, an experimentally tested, general theoretical model of phototaxis seems unavailable to date. Here, we present accurate measurements of the behavior of the algaEuglena graciliswhen exposed to controlled light fields. Analysis ofE. gracilis’ phototactic accumulation dynamics over a broad range of light intensities proves that the classic Keller–Segel mathematical framework for taxis provides an accurate description of both positive and negative phototaxis only when phototactic sensitivity is modeled by a generalized “receptor law,” a specific nonlinear response function to light intensity that drives algae toward beneficial light conditions and away from harmful ones. The proposed phototactic model captures the temporal dynamics of both cells’ accumulation toward light sources and their dispersion upon light cessation. The model could thus be of use in integrating models of vertical phytoplankton migrations in marine and freshwater ecosystems, and in the design of bioreactors.

Highway Tunnel Lighting Research Based on Mesopic Vision

2011 ◽  
Vol 71-78 ◽  
pp. 4061-4064
Author(s):  
Yong Yang ◽  
Chuan Zheng Zhu ◽  
Lei Wang
Keyword(s):  
Reaction Time ◽  
Design Method ◽  
B Value ◽  
Light Sources ◽  
White Led ◽  
Mesopic Vision ◽  
Highway Tunnel ◽  
Function Fitting ◽  
Sodium Lamp ◽  
High Pressure Sodium Lamp

The white LED and high-pressure sodium lamp (HPS) are used to simulate highway tunnel lighting under different background brightness (abbreviated as B) conditions, from a series of reaction time tests, the result shows that white LED can provide shorter reaction time for observers compared with HPS, further research suggests under the mesopic vision, different kinds of light sources maybe have unlike brightness, although which is identical under the photopic vision. From the luminous spectrum test and mesopic vision spectral luminous efficiency function fitting calculation, the mesopic equivalent brightness can be determined with certain light source and B value. This conclusion would provide a more accurate and lower energy consumption lighting design method for highway tunnel.

Auto White Balance Algorithm in Digital Camera

2012 ◽  
Vol 182-183 ◽  
pp. 2080-2084
Author(s):  
Jie Li ◽  
Xue Xiang Wang ◽  
Hao Liu
Keyword(s):  
Hardware Implementation ◽  
Digital Camera ◽  
Low Complexity ◽  
Light Sources ◽  
Light Conditions ◽  
Threshold Method ◽  
White Balance ◽  
White Point ◽  
A New Technique ◽  
Better Than

Auto white balance (AWB) is an important function of digital camera. The purpose of white balance is to adjust the image to make it look like taken under standard light conditions. We present a new technique to detect the reference white point of image in this paper. This technique detects the white point of image by using dynamic threshold method, thus making it more flexible and more applicable compared to other algorithms. We test 50 images which were taken under different light sources, and find that this algorithm is better than or comparable to other algorithms both in subjective and objective aspects. At the same time, this algorithm has low complexity, and it can be easily applied to hardware implementation.

scholarly journals MORPHOLOGICAL AND PHYSIOLOGICAL PLASTICITY OF SAPLINGS OF Cabralea canjerana (Vell.) MART. IN DIFFERENT LIGHT CONDITIONS

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Anna Paula Lora Zimmermann ◽  
Frederico Dimas Fleig ◽  
Luciane Almeri Tabaldi ◽  
Suelen Carpenedo Aimi
Keyword(s):  
Leaf Area ◽  
Photosynthetic Activity ◽  
Dry Mass ◽  
Chlorophyll B ◽  
Light Conditions ◽  
Forest Fragment ◽  
Lower Content ◽  
Physiological Plasticity ◽  
Chlorophyll A And B ◽  
Number Of Leaves

ABSTRACT This work was carried out to verify the plasticity of saplings of Cabralea canjerana plants and their capacity to adapt to different light environments by means of morphological and physiological characteristics. For this, 12 plants of a secondary Deciduous Seasonal Forest fragment were selected, six growing under canopy and six in full sun. Trees were classified according to their sociological position as emergent and dominated. The leaves were classified as apical, intermediate and basal according to their position in the canopy. The variables measured were: total number of leaves, width, length, thickness, leaf area and dry mass of leaflets; content of chlorophyll a and b and carotenoids. Emergent leaflets of the upper position of the canopy in full sun, which are considered the most exposed to luminosity, presented xeromorphic characteristics such as leaflet size reduction, greater limbus thickness, smaller leaf area and lower content of chlorophyll b. The similarity in the dry mass and pigment content demonstrates that the photosynthetic activity of the C. canjerana plants analyzed is not being affected by the different conditions of the environment, which demonstrates the plasticity of the species and its capacity of development in several light conditions.

scholarly journals The effects of light-emitting diode lighting on greenhouse plant growth and quality

2013 ◽  
Vol 22 (2) ◽  
pp. 223-234 ◽  
Author(s):  
Margit Olle ◽  
Akvile Viršile
Keyword(s):  
Growth Promotion ◽  
Light Emitting Diode ◽  
Red Light ◽  
Growth Yield ◽  
Sweet Pepper ◽  
Light Sources ◽  
Light Emitting ◽  
Sodium Lamp ◽  
Greenhouse Plant ◽  
High Pressure Sodium Lamp

The aim of this study is to present the light emitting diode (LED) technology for greenhouse plant lighting and to give an overview about LED light effects on photosynthetic indices, growth, yield and nutritional value in green vegetables and tomato, cucumber, sweet pepper transplants. The sole LED lighting, applied in closed growth chambers, as well as combinations of LED wavelengths with conventional light sources, fluorescent and high pressure sodium lamp light, and natural illumination in greenhouses are overviewed. Red and blue light are basal in the lighting spectra for green vegetables and tomato, cucumber, and pepper transplants; far red light, important for photomorphogenetic processes in plants also results in growth promotion. However, theoretically unprofitable spectral parts as green or yellow also have significant physiological effects on investigated plants. Presented results disclose the variability of light spectral effects on different plant species and different physiological indices.

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