Blue Light Conditions Research Articles

Estimation of linear and cyclic electron flows in photosynthesis based on 13C-metabolic flux analysis

Photosynthetic organisms produce ATP and NADPH using light as an energy source and further utilize these cofactors during metabolism. Photosynthesis involves linear and cyclic electron flows; as the cyclic electron flow produces ATP more effectively than the linear electron flow without NADPH, the cell efficiently adjusts ATP and NADPH production using the two different pathways. Nevertheless, direct measurement of ATP and NADPH production during photosynthesis has been difficult. In the present study, the photosynthetic ATP and NADPH production rates of Synechocystis sp. PCC 6803 under three different single peak wavelength lights (blue: 470nm, R630: 630nm, and R680: 680nm) were evaluated based on 13C-metabolic flux analysis (13C-MFA) by considering the mass balance of ATP and NADPH between photosynthesis and metabolism. The ratios of ATP/NADPH production via photosynthesis were estimated as 3.13, 1.70, and 2.10 under blue, R630, and R680 light conditions, respectively. Moreover, the linear and cyclic electron flow ratios were estimated to be 1.1-2.2, 0.2-0.5, and 0.5-1.0 under blue, R630, and R680 light conditions, respectively. The predicted linear and cyclic electron flow ratios were consistent with the excitation ratio between photosystems I and II, as observed in the steady-state fluorescence spectra.

Plasma Rich in Growth Factors Enhances Cell Survival after in Situ Retinal Degeneration

Purpose: The purpose of this study was to examine the effect of plasma rich in growth factors (PRGFs) under blue light conditions in an in vivo model of retinal degeneration. Methods: Male Wistar rats were exposed to dark/blue light conditions for 9 days. On day 7, right eyes were injected with saline and left eyes with PRGF. Electroretinography (ERG) and intraocular pressure (IoP) measurements were performed before and after the experiment. After sacrifice, retinal samples were collected. Hematoxylin and eosin staining was performed to analyze the structure of retinal sections. Immunofluorescence for brain-specific homeobox/POU domain protein 3A (Brn3a), choline acetyltransferase (ChAT), rhodopsin, heme oxygenase-1 (HO-1), and glial fibrillary acidic protein (GFAP) was performed to study the retinal conditions. Results: Retinal signaling measured by ERG was reduced by blue light and recovered with PRGF; however, IoP measurements did not show significant differences among treatments. Blue light reduced the expression for Brn3a, ChAT, and rhodopsin. Treatment with PRGF showed a recovery in their expressions. HO-1 and GFAP results showed that blue light increased their expression but the use of PRGF reduced the effect of light. Conclusions: Blue light causes retinal degeneration. PRGF mitigated the injury, restoring the functionality of these cells and maintaining the tissue integrity.

Lighting Conditions Influence the Dynamics of Protease Synthesis and Proteasomal Activity in the White Rot Fungus Cerrena unicolor.

Recent transcriptomic and biochemical studies have revealed that light influences the global gene expression profile and metabolism of the white-rot fungus Cerrena unicolor. Here, we aimed to reveal the involvement of proteases and ubiquitin-mediated proteolysis by the 26S proteasome in the response of this fungus to white, red, blue and green lighting conditions and darkness. The changes in the expression profile of C. unicolor genes putatively engaged in proteolysis were found to be unique and specific to the applied wavelength of light. It was also demonstrated that the activity of proteases in the culture fluid and mycelium measured using natural and synthetic substrates was regulated by light and was substrate-dependent. A clear influence of light on protein turnover and the qualitative and quantitative changes in the hydrolytic degradation of proteins catalyzed by various types of proteases was shown. The analysis of activity associated with the 26S proteasome showed a key role of ATP-dependent proteolysis in the initial stages of adaptation of fungal cells to the stress factors. It was suggested that the light-sensing pathways in C. unicolor are cross-linked with stress signaling and secretion of proteases presumably serving as regulatory molecules.

Blue Light Induced Edible Mushroom (Lentinula edodes) Proteomic Analysis.

Blue light is an important environmental factor that induces mushroom growth and morphological changes. In this study, after confirming the morphological difference between Lentinula edodes (LE) under blue light condition (BL) and lightless condition (LL), the increase and decrease in LE protein and the expression of RNA of each protein were confirmed under each condition. LE specimens grown in BL and LL were identified by 253 spots in BL through 2D electrophoresis and LC-MSMS analysis, and 22 types of proteins were identified. It was confirmed that 14 types of proteins showed reduced expression in BL compared to LL. On the other hand, eight kinds of proteins with increased expression in blue light compared to LL were identified. As a result of confirming the difference from the expression pattern in 2D electrophoresis through Quantitative Real-Time PCR, it was confirmed that the expression pattern of the two proteins showed a difference. Therefore, this study will be a key study on the changes in mushroom morphology induced by blue light and the proteins that induce it.

Photocatalytic Unsymmetrical Coupling of 2-Substituted Quinolines: Synthesis and Evaluation of the Antiplasmodial Potential of β-Norbenzomorphan Frameworks

We herein report unsymmetrical coupling of 2-methylquinolines under the blue LED light conditions using iridium-based photocatalyst. This methodology represents the direct synthetic method for the ...

Effects of Darkness and Light Spectra on Nutrients and Pigments in Radish, Soybean, Mung Bean and Pumpkin Sprouts.

Fresh sprouts are an important source of antioxidant compounds and contain useful phytonutrients in the human diet. Many factors, such as the time of germination and types of light, influence the physiological processes and biosynthetic pathways in sprouts. The effect of red, blue and white light vs. dark conditions on the quality parameters in different sprout species after 5 d of germination was evaluated. Total ascorbate, soluble proteins, sugars, phenolic compounds, and pigments, such as carotenoids, chlorophylls, and anthocyanins, were investigated in radishes, soybeans, mung beans, and pumpkin sprouts. The light treatments increased the contents of vitamin C and the various pigments in all sprouts, conversely, they increased the soluble proteins and sugars, including d-glucose, d-fructose and sucrose, in soybeans and pumpkins, respectively. The dark treatment prevented the decrease in dry matter due to the lighting, while the red light induced an increase in polyphenols in soybean. These results suggest that the nutritional content of different sprouts grown under different light conditions depend on the dark or specific spectral wavelength used for their growth. The manuscript may increase the knowledge on light use for the industrialized food production aiming at preserving the phytonutrient content of vegetables, increasing the consumer health, or developing tailored diets for specific nutritional needs.

First person – Lana de Vries

ABSTRACTFirst Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping early-career researchers promote themselves alongside their papers. Lana de Vries is first author on ‘Bumblebees land remarkably well in red–blue greenhouse LED light conditions’, published in BiO. Lana is a PhD Candidate in the lab of Dr Florian Muijres at the Experimental Zoology Group, Wageningen University & Research, studying insects, especially social insects like bumblebees, since these kinds of animals can build complex social systems with an organized division of tasks.

Effect of thidiazuron and monochromatic light on shoot development in vitro culture of Polygonum cuspidatum Sieb et Zucc

Polygonum cuspidatum Sieb. et Zucc, a medicinal plant, contains many phenolic compounds such as resveratrol. It has antioxidant, antibacterial, anti-cancer, HIV, and neuron protective properties. In this study, stem segments having an auxiliary bud were cultured in vitro on MS medium supplemented with TDZ at 0.1 mg/L for obtaining the highest number of shoots (8–9 shoots/cluster after eight weeks). The bud shoots were originated from the differentiation in the periphery of the lateral meristem. After eight weeks, the shoots cultured under the monochromatic light showed that the plant height, fresh and dry weight was higher than those grown under the fluorescent light at the same intensity of 50 µmol photon/m2/sec. Blue LED reduced the number of shoots/cluster, and respiration intensity of the inoculum compared to the red LED or fluorescent light conditions. However, after eight weeks, the total sugar and phenolic content in leaves and stems, as well as the resveratrol content of shoots under blue light, were always higher than under red LED or fluorescent light. Moreover, when samples were exposed under the one-week blue light condition at a double intensity (100 µmol photon/m2/sec), the shoot clusters growing under blue LED also had a remarkably high total phenolic content and significantly high resveratrol levels compared to the two other treatments. The roles of endogenous growth regulators in shoot clusters under different lighting conditions were also analyzed and discussed.

Transcriptome analysis of the edible mushroom Lentinula edodes in response to blue light.

Lentinula edodes is one of the most popular edible mushrooms worldwide and contains important medicinal components such as lentinan, ergosterol, and eritadenine. Mushroom metabolism is regulated by the mycelia and fruit body using light; however, in mushrooms, the underlying molecular mechanisms controlling this process as well as light-induced gene expression remain unclear. Therefore, in this study, we compared morphological changes and gene expression in the fruit bodies of L. edodes cultivated under blue light and continuous darkness. Our results showed that blue light primarily induced pileus growth (diameter and thickness) compared to dark cultivation. Alternatively, stipe length development was promoted by dark cultivation. We also performed RNAseq on L. edodes under the blue light/dark cultivation conditions. A total of 12,051 genes were used for aligning the Illumina raw reads and 762 genes that showed fold change cut-offs of >|2| and significance p-values of <0.05 were selected under blue light condition. Among the genes which showed two-fold changed genes, 221 were upregulated and 541 were downregulated. In order to identify blue light induced candidate genes, differentially expressed genes (DEGs) were selected according to 4-fold changes and validated by RT-PCR. We identified 8 upregulated genes under blue light condition, such as DDR48-heat shock protein, Fasciclin-domain-containing protein and carbohydrate esterase family 4 protein, FAD NAD-binding domain-containing protein that are involved in morphological development of primordium and embryonic muscle development, cell adhesion and affect the structure of cellulosic and non-cellulosic cell walls of fruit body development, and photoreceptor of blue light signaling for fruit body and pigment development, respectively. This study provides valuable insights into the molecular mechanisms underlying the role of blue light in mushroom growth and development and can thus contribute to breeding programs to improve mushroom cultivation.

An Optogenetic Tool for Induced Protein Stabilization Based on the Phaeodactylum tricornutum Aureochrome 1a Light–Oxygen–Voltage Domain

Control of cellular events by optogenetic tools is a powerful approach to manipulate cellular functions in a minimally invasive manner. A common problem posed by the application of optogenetic tools is to tune the activity range to be physiologically relevant. Here, we characterized a photoreceptor of the light–oxygen–voltage (LOV) domain family of Phaeodactylum tricornutum aureochrome 1a (AuLOV) as a tool for increasing protein stability under blue light conditions in budding yeast. Structural studies of AuLOVwt, the variants AuLOVM254, and AuLOVW349 revealed alternative dimer association modes for the dark state, which differ from previously reported AuLOV dark-state structures. Rational design of AuLOV-dimer interface mutations resulted in an optimized optogenetic tool that we fused to the photoactivatable adenylyl cyclase from Beggiatoa sp. This synergistic light-regulation approach using two photoreceptors resulted in an optimized, photoactivatable adenylyl cyclase with a cyclic adenosine monophosphate production activity that matches the physiological range of Saccharomyces cerevisiae. Overall, we enlarged the optogenetic toolbox for yeast and demonstrated the importance of fine-tuning the optogenetic tool activity for successful application in cells.

Comparative Transcriptome Analyses of Gene Response to Different Light Conditions of Camellia oleifera Leaf Using Illumina and Single-Molecule Real-Time-Based RNA-Sequencing

Camellia oleifera Abel. is a critical oil tree species. Camellia oil, which is extracted from the seeds, is widely regarded as a premium cooking oil, with the content of oleic acid being over 80%. Light is thought to be one of the largest essential natural components in the regulation of plant developmental processes, and different light qualities can considerably influence plant physiological and phenotypic traits. In this research, we examined the growth and physiological responses of C. oleifera “MIN 43” cultivar plantlets to three different wavelengths of light, containing white, red, and blue light, and we utilized the combination of the PacBio single-molecule real-time (SMRT) and Illumina HiSeq RNA sequencing to obtain the mRNA expression profiles. The results showed that plantlets growing under blue light conditions displayed superior growth performance, including stimulated enhancement of the leaf area, increased leaf number, increased chlorophyll synthesis, and improved photosynthesis. Furthermore, SMAT sequencing created 429,955 reads of inserts, where 406,722 of them were full-length non-chimeric reads, and 131,357 non-redundant isoforms were produced. Abundant differentially expressed genes were found in leaves under different light qualities by RNA-sequencing. Gene expression profiles of actin, dynein, tubulin, defectively organized tributaries 3 (DOT3), and ADP ribosylation factor 5 (ARF5) were associated with the greatest leaf performance occurring under blue light conditions. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified hundreds of pathways involved in different light conditions. The pathways of the plant circadian rhythm and hormone signal transduction were associated with different light quality responses in C. oleifera. Phytochrome B (PHYB), constitutively photomorphogenic 1 (COP1), long hypocotyl 5 (HY5), auxin/indole-3-acetic acid (AUX/IAA), Gretchen Hagen 3 (GH3), and small auxin-up RNA (SAUR), which were differentially expressed genes involved in these two pathways, play a vital role in responses to different wavelengths of light in C. oleifera. In addition, blue light significantly promotes flavonoid biosynthesis via changing expression of related genes.

Heat pain modulation with virtual water during a virtual hand illusion

Immersive virtual reality is a powerful method to modify the environment and thereby influence experience. The present study used a virtual hand illusion and context manipulation in immersive virtual reality to examine top-down modulation of pain. Participants received painful heat stimuli on their forearm and placed an embodied virtual hand (co-located with their real one) under a virtual water tap, which dispensed virtual water under different experimental conditions. We aimed to induce a temperature illusion by a red, blue or white light suggesting warm, cold or no virtual water. In addition, the sense of agency was manipulated by allowing participants to have high or low control over the virtual hand’s movements. Most participants experienced a thermal sensation in response to the virtual water and associated the blue and red light with cool/cold or warm/hot temperatures, respectively. Importantly, the blue light condition reduced and the red light condition increased pain intensity and unpleasantness, both compared to the control condition. The control manipulation influenced the sense of agency, but did not influence pain ratings. The large effects revealed in our study suggest that context effects within an embodied setting in an immersive virtual environment should be considered within VR based pain therapy.

Light-regulated synthesis of extra- and intracellular enzymes related to wood degradation by the white rot fungus Cerrena unicolor during solid-state fermentation on ash sawdust-based medium.

The light-dependent metabolism of the white rot basidiomycete Cerrena unicolor FCL139 has already been demonstrated using transcriptomic and Biolog-based approaches. To further analyze the influence of light on C. unicolor wood degradation, we measured the activity of an array of CAZymes (carbohydrate-active enzymes) and enzymes involved in the redox system of fungal cells associated with lignolysis. Extra- and intracellular enzymatic extracts were obtained from solid-state ash sawdust C. unicolor cultures cultivated for 14 days under red, blue, green, or white light conditions, or in the dark. Light greatly influenced the synthesis of MnP, total cellulases, endo-1,4-β-glucanase, endo-1,4-β-xylanase, catalase, and superoxide dismutase. The production of MnP and catalase was evidently stimulated by white light. It is also worth noticing that blue light caused a gradual increase in the activity of total cellulases throughout the entire period of C. unicolor growth. Moreover, endo-1,4-β-glucanase showed the highest activity on day 13 of fungus cultivation and the production of laccase and β-glucosidase appeared to be the least influenced by light. However, the strongest activity of the endo-1,4-β-xylanase was observed in the dark. It seemed that light not only influenced the regulation of the synthesis of the wood-degrading enzymes at different levels, but also acted indirectly by affecting production of enzymes managing harmful lignin by-products causing oxidative stress. The ability of the fungus to decompose woody plant material is clearly influenced by environmental factors.

Variations of Saponarin Content in Young Barley Leaves Illuminated with Different Light-Emitting Diodes (LEDs)

In this study, the effect of light on the regulation of flavonoid production in young barley leaves (YBLs) was investigated. YBLs following germination were illuminated with different light-emitting diode (LED) lights, i.e. blue, red, far-red light, along with fluorescence and dark conditions as controls, and as the main flavonoid, saponarin content of YBLs was analyzed quantitatively with HPLC. In addition, the antioxidant activities of the crude ethanoic extracts of YBLs were analyzed by several antioxidant assays. The content of saponarin in blue light-illuminated barley leaves is two or three times higher than those in barley leaves with other lighting conditions, i.e. red, far-red, and the content with fluorescence and even dark conditions as controls. However, the levels of saponarin among the leaves illuminated with other lighting systems show no significant difference. And, the antioxidant potentials of the extracts of YBLs demonstrated same tendency shown in saponarin levels. Our results suggested that blue lighting conditions might evoke the photoprotection changes in YBLs, leading elevated level of saponarin, consequently increasing their antioxidant potentials.

Precise Cross-Dimensional Regulation of the Structure of a Photoreversible DNA Nanoswitch.

In this study, an accurately and digitally regulated allosteric nanoswitch based on the conformational control of two DNA hairpins was developed. By switching between UV irradiation and blue light conditions, the second molecular beacon (H#2) would bind/separate with a repression sequence (RES) via the introduced PTG molecules (a photosensitive azobenzene derivative), resulting in the target aptamer sequence in the first molecular beacon (H#1) not being able/being able to hold the stem-loop configuration, hence losing/regaining the ability to bind with the target. Importantly, we successfully monitor conformation changes of the nanoswitch by an elegant mathematical model for connecting Ki (the dissociation constant between RES and H#2) with Kd (the overall equilibrium constant of the nanoswitch binding the target), hence realizing "observing" DNA structure across dimensions from "structural visualization" to digitization and, accurately, digitally regulating DNA structure from digitization to "structural visualization".

Effect of light specters (red and blue) on two-potato varieties tissue (spunta and Agria)

This study was carried out in plant tissue culture laboratory which belong to bio technology research center in order to test the effect of raid and blue spectral light colors and white lighting as a control and white fluorescent lamps as a second control on plant growth stages while two potato variety ( Spunta , Agria) were used in this experiment . potato plant samples were collected and cultured in special jars contain MS media after being sterilized by Clorox solution in order to avoid the any contamination risk , while the culture stage of the explant started in sterilized condition in sited the hood cabinet, wherever the culture stage completed the cultured plants were placed in the growth room under controlled condition with raid , blue and normal light condition. The obtained results showed that the wait normal color treatment was significantly higher than the other two treatments in plant length factor for the tow used potato variety, while for the number of leaves factor the results showed that the normal light color treatment was significantly higher than the other two treatments in plant number of leaves factor followed by raid color treatment in the two used variety Spunta and Agria while the Raid color treatment scored average of leaves (23.9, 23.3 ) leaf respectively.

Assessment of photocatalytic performance of Fe/N-TiO2 photocatalysts prepared by liquid phase plasma process

Abstract To improve the photocatalytic performance of TiO2 photocatalysts, a new method, liquid phase plasma (LPP) method, was used to introduce nitrogen and iron oxide. Interstitial or substitutional nitrogen and Fe3+ iron nanoparticles were impregnated on the surface of TiO2 by LPP reaction without additional chemical reduction agent and the amount of iron of modified TiO2 photocatalysts was affected by the amount of initial precursor. The adsorption edge of modified TiO2 photocatalysts was shifted to the visible region in proportion to the amount of nitrogen and iron oxide, and the band gap energy was decreased, and the photocatalytic activity was confirmed by PL and EPR analysis. The photocatalytic activities of modified TiO2 photocatalysts were measured under UV and blue LED lamps and compared with pure TiO2 powder (P-25). The modified TiO2 exhibited better photocatalytic degradation performance than pure TiO2 under blue LED light conditions, but exhibited low degradation activity under UV LED light conditions. Through GC–MS analysis, it was found that the methylene blue was finally decomposed into an inorganic substance through intermediates such as benzene sulfonic acid and phenol by OH radicals. From these results, we found that the modified TiO2 photocatalysts can be easily prepared using the LPP method and can be used in the visible region.

Effect of blue light-emitting diode light and antioxidantpotential in a somatic cell.

Light is an indispensable part of routine laboratory workin which conventional light is generally used. Light-emitting diodes (LEDs) have come to replace conventional light, andthus could be a potent target in biomedical studies. Since blue light is a major component of visible light wavelength, in this study, using a somatic cell from the African green monkey kidney, we assessed the possible consequences of the blue spectra of LED light in future animal experiments and proposed a potent mitigation against light-induced damage. COS-7 cells were exposed to blue LED light (450 nm) and the growth and deoxyribonucleic acid (DNA) damage were assessed at different exposure times. A higher suppression in cell growth and viability was observed under a longer period of blue LED light exposure. The number of apoptotic cells increased as the light exposure time was prolonged. Reactive oxygen species (ROS) generation was also elevated in accordance to the extension of light exposure time. A comparison withdark-maintained cells revealed that the upregulation of ROS by blue LED light plays a significant role in causing cellular dysfunction in DNA in a time-dependent manner. In turn, antioxidant treatment has been shown to improve cell growth and viability under blue LED light conditions. This indicates that antioxidants havepotential against blue LED light-induced somatic cell damage. It is expected that this study will contribute to the understanding of the basic mechanism of somatic cell death under visible light and maximize the beneficial use of LED light in future animal experiments.

Effect of light quality on growth rate, carbohydrate accumulation, fatty acid profile and lutein biosynthesis of Chlorella sp. AE10

Microalgae are feedstocks for multiple product development based on algal biorefinery concept. The effects of light quality (white, red and blue light emitting diodes) and macro-element starvations on Chlorella sp. AE10 were investigated under 20% CO2 and 850 µmol m−2 d−1. Nitrogen and phosphorus starvations had negative effects on its growth rate. The biomass productivities were decreased from day 1 and the highest one was 1.90 g L−1 d−1 under white light conditions. Phosphorus starvation promoted carbohydrate accumulation under three LED light sources conditions and the highest carbohydrate content was 75.9% using red light. Blue light increased lutein content to 9.58 mg g−1. The content of saturated fatty acids was significantly increased from 37.51% under blue light and full culture medium conditions to 77.44% under blue light and nitrogen starvation conditions. Chlorella sp. AE10 was a good candidate for carbohydrate and lutein productions.

Near Room Temperature Light-Activated WS2-Decorated rGO as NO2 Gas Sensor.

The NO2 response in the range of 200 ppb to 1 ppm of a chemoresistive WS2-decorated rGO sensor has been investigated at operating temperatures of 25 °C and 50 °C in dry and humid air (40% RH) under dark and Purple Blue (PB) light conditions (λ = 430 nm). Few-layers WS2, exfoliated by ball milling and sonication technique, with average dimensions of 200 nm, have been mixed with rGO flakes (average dimension 700 nm) to yield WS2-decorated rGO, deposited on Si3N4 substrates, provided with platinum (30 μm gap distance) finger-type electrodes. TEM analysis showed the formation of homogeneous and well-dispersed WS2 flakes distributed over a thin, continuous and uniform underlying layer of interconnected rGO flakes. XPS and STEM revealed a partial oxidation of WS2 flakes leading to the formation of 18% amorphous WO3 over the WS2 flakes. PB-light irradiation and mild heating of the sensor at 50 °C substantially enhanced the baseline recovery yielding improved adsorption/desorption rates, with detection limit of 400 ppb NO2 and reproducible gas responses. Cross sensitivity tests with humid air interfering vapor highlighted a negligible influence of water vapor on the NO2 response. A charge carrier mechanism between WS2 and rGO is proposed and discussed to explain the overall NO2 and H2O response of the WS2–rGO hybrids.