Continuous Blue Light Irradiation Research Articles

Integrated transcriptome and metabolome analysis reveals anthocyanin biosynthesis mechanisms in pepper (Capsicum annuum L.) leaves under continuous blue light irradiation

BackgroundDifferent metabolic compounds give pepper leaves and fruits their diverse colors. Anthocyanin accumulation is the main cause of the purple color of pepper leaves. The light environment is a critical factor affecting anthocyanin biosynthesis. It is essential that we understand how to use light to regulate anthocyanin biosynthesis in plants.ResultPepper leaves were significantly blue–purple only in continuous blue light or white light (with a blue light component) irradiation treatments, and the anthocyanin content of pepper leaves increased significantly after continuous blue light irradiation. This green-to-purple phenotype change in pepper leaves was due to the expression of different genes. We found that the anthocyanin synthesis precursor-related genes PAL and 4CL, as well as the structural genes F3H, DFR, ANS, BZ1, and F3’5’H in the anthocyanin synthesis pathway, had high expression under continuous blue light irradiation. Similarly, the expression of transcription factors MYB1R1-like, MYB48, MYB4-like isoform X1, bHLH143-like, and bHLH92-like isoform X3, and circadian rhythm-related genes LHY and COP1, were significantly increased after continuous blue light irradiation. A correlation network analysis revealed that these transcription factors and circadian rhythm-related genes were positively correlated with structural genes in the anthocyanin synthesis pathway. Metabolomic analysis showed that delphinidin-3-O-glucoside and delphinidin-3-O-rutinoside were significantly higher under continuous blue light irradiation relative to other light treatments. We selected 12 genes involved in anthocyanin synthesis in pepper leaves for qRT-PCR analysis, and the accuracy of the RNA-seq results was confirmed.ConclusionsIn this study, we found that blue light and 24-hour irradiation together induced the expression of key genes and the accumulation of metabolites in the anthocyanin synthesis pathway, thus promoting anthocyanin biosynthesis in pepper leaves. These results provide a basis for future study of the mechanisms of light quality and photoperiod in anthocyanin synthesis and metabolism, and our study may serve as a valuable reference for screening light ratios that regulate anthocyanin biosynthesis in plants.

Induction of Skin Cancer by Long-Term Blue Light Irradiation.

Presently, people are not only exposed to sunlight but also to a large amount of blue light from personal computers and smartphones. This blue light has various effects on the living body. However, its effect on the induction of skin cancer is unknown. In this study, we investigated the induction of skin cancer by long-term blue light irradiation. Hairless mice were irradiated with blue light (LED; peak emission 479 nm) every day for one year, and a control was irradiated with white light (LED), green light (LED; peak emission 538 nm), and red light (LED; peak emission 629 nm) for one year, respectively. Skin cancer was induced only in the mice exposed to blue light. Long-term blue light irradiation also increased the migration of neutrophils and macrophages involved in carcinogenesis in the skin. In neutrophils, an increased expression of citH3 and PAD4 was observed, suggesting the possibility of NETosis. Conversely, in macrophages, inflammatory macrophages (type 1 macrophages) increased and anti-inflammatory macrophages (type 2 macrophages) decreased due to continuous blue light irradiation. These findings suggest that long-term continuous irradiation with blue light induces neutrophil NETosis and an increase in type 1 macrophages, resulting in skin cancer.

Comparison of the Effects of Intermittent Blue Light Irradiation Therapy and Continuous Blue Light Irradiation Therapy in the Clinical Treatment of Neonatal Jaundice

Comparison of the Effects of Intermittent Blue Light Irradiation Therapy and Continuous Blue Light Irradiation Therapy in the Clinical Treatment of Neonatal Jaundice

Effect Comparison of Intermittent Blue Light Irradiation and Continuous Blue Light Irradiation Assisted Yinzhi Huang Oral Liquid in the Treatment of Neonatal Jaundice

Effect Comparison of Intermittent Blue Light Irradiation and Continuous Blue Light Irradiation Assisted Yinzhi Huang Oral Liquid in the Treatment of Neonatal Jaundice

Spectroscopic and structural characteristics of a dual-light sensor protein, PYP-phytochrome related protein.

PYP-phytochrome related (Ppr) protein contains the two light sensor domains, photoactive yellow protein (PYP) and bacteriophytochrome (Bph), which mainly absorb blue and red light by the chromophores of p-coumaric acid (pCA) and biliverdin (BV), respectively. As a result, Ppr has the ability to photoactivate both domains together or separately. We investigated the photoreaction of each photosensor domain under different light irradiation conditions and clarified the inter-dependency between these domains. Within the first 10 s of blue light illumination, Ppr (Holo-Holo-Ppr) accompanied by both pCA and BV demonstrated spectrum changes reflecting PYPL accumulation, which can also be observed in Ppr containing only pCA (Holo-Apo-Ppr), and a fragment of Ppr lacking the C-terminal Bph domain. Although Holo-Apo-Ppr showed PYPL as a major photoproduct under blue light, as seen in the Bph-truncated Ppr, the equilibrium in the Holo-Holo-Ppr was shifted from PYPL to PYPM as the reaction progresses under blue light. Concomitantly, the spectrum of Bph exhibited subtle but distinguishable alteration. Together with the fact, it can be proposed that Bph with BV influences the photoreaction of PYP in Ppr, and vice versa. SAXS measurements revealed substantial tertiary structure changes in Holo-Holo-Ppr under continuous blue light irradiation within the first 5 min time domain. Interestingly, the changes in tertiary structure were partially suppressed by photoactivation of the Bph domain. These observations indicate that the photoreactions of the PYP and Bph domains are coupled with each other, and that the interplay realizes the structural switch, which might be involved in downstream signal transduction.

Analysis of therapeutic effect of intermittent and continuous phototherapy on neonatal hemolytic jaundice.

Clinical efficacy and adverse reaction rates of ABO hemolytic jaundice in patients with continuous and intermittent blue light irradiation were compared, to provide reference for clinical treatment of neonatal ABO hemolytic jaundice. A retrospective analysis of 307 patients with neonatal hemolytic jaundice admitted to Qilu Hospital of Shandong University (Qingdao) from January 2010 to December 2017 was undertaken. A total of 165 cases of children with continuous blue light irradiation and 142 cases of intermittent blue light irradiation were analyzed. Also the serum bilirubin levels, phototherapy time and frequency, treatment efficiency and adverse reaction rates were compared between the groups. The phototherapy time of children in the continuous phototherapy group was significantly higher from the intermittent phototherapy group, and the difference was statistically significant (t=26.800, P<0.001). Before treatment, there was no significant difference in serum bilirubin levels between continuous and intermittent phototherapy groups (P>0.050). Serum bilirubin levels of patients in continuous and intermittent phototherapy groups were lower than both previous and before treatment period, and differences were statistically significant (P<0.001). The overall effective rate of the continuous phototherapy group was higher than that of the intermittent phototherapy group (P>0.050). The adverse reaction rates after treatment in the continuous phototherapy group was significantly higher than the intermittent phototherapy group (P<0.050). After the symptomatic treatment in children, the adverse reactions ceased. The therapeutic effect of intermittent blue light irradiation on neonatal ABO hemolytic jaundice was consistent with the continuous blue light irradiation treatment, and the intermittent blue light irradiation treatment has a low adverse reaction rate, and is worth promotion in clinical practice.

Comparison of the effect and prognosis of intermittent blue light and continuous blue light therapy for neonatal jaundice

Objective To observe the effect of intermittent and continuous blue light therapy for pathological neonatal jaundice, and to evaluate the prognosis of newborns. Methods 214 patients with pathologic neonatal jaundice who treated with blue light irradiation were slected, they were randomly divided into two groups according to the admission number combined with single and double numbers, 107 patients in each group.Group A received continuous blue light irradiation treatment.Group B received intermittent blue light irradiation.The clinical efficacy and prognosis of children, blue light exposure time, serum total bilirubin (TBiL) recovery time, the hospitalization time and the adverse reactions during the treatment were observed.The levels of serum TBiL were measured before and after light exposure 3, 5 days. Results The total effective rate of group B was 97.18% (104/107), which was higher than that of group A [90.65%(97/107)], the difference was statistically significant (χ2=10.30, P<0.05). The time of blue light irradiation and hospital stay time of group B were (71.59±7.05)d and (11.51±1.23)d, respectively, which were significantly shorter than those of group A [(79.54±6.82)d and (13.64±1.18)d], the differences were statistically significant(u=11.42, 9.87, all P<0.05). The level of TBiL of group B was (96.28±10.25)μmol/L, which was significantly lower than (104.52±10.31) μmol/L of group A (u=8.94, P<0.05). The incidence rate of adverse reactions in group B was 2.55% (4/157), which was lower than that in group A [7.01%(11/157)], the difference was statistically significant (χ2=9.66, P<0.05). The prognosis of neonatal in the two groups was good. Conclusion The intermittent and continuous blue light in the treatment of pathological neonatal jaundice has good clinical effect and the neonatal prognosis is good.The clinical efficacy of intermittent blue light irradiation is better, which can significantly shorten the treatment time and has higher safety. Key words: Jaundice, neonatal; Photochemotherapy; Prognosis

Dissipative and Autonomous Square-Wave Self-Oscillation of a Macroscopic Hybrid Self-Assembly under Continuous Light Irradiation.

Building a bottom-up supramolecular system to perform continuously autonomous motions will pave the way for the next generation of biomimetic mechanical systems. In biological systems, hierarchical molecular synchronization underlies the generation of spatio-temporal patterns with dissipative structures. However, it remains difficult to build such self-organized working objects via artificial techniques. Herein, we show the first example of a square-wave limit-cycle self-oscillatory motion of a noncovalent assembly of oleic acid and an azobenzene derivative. The assembly steadily flips under continuous blue-light irradiation. Mechanical self-oscillation is established by successively alternating photoisomerization processes and multi-stable phase transitions. These results offer a fundamental strategy for creating a supramolecular motor that works progressively under the operation of molecule-based machines.

Blue light inactivates plasma membrane H(+)-ATPase in pulvinar motor cells of Phaseolus vulgaris L.

Unilateral blue light irradiation induces bending of pulvini of Phaseolus vulgaris towards the source of light. The pulvinar bending is caused by a decrease in turgor pressure of motor cells that are irradiated with blue light. Decrease in the turgor pressure is caused by the net efflux of K(+) and counter anions, accompanying membrane depolarization. In the present study the effect of blue light on the activity of plasma membrane H(+)-ATPase was studied in relation to the membrane depolarization. The activity of the plasma membrane H(+)-ATPase was measured using protoplast suspensions prepared from laminar pulvini from primary leaves. A pulse of blue light under continuous red light irradiation induced both a transient increase in the external pH and transient inhibition of the vanadate-sensitive ATPase. Continuous blue light irradiation under continuous red light irradiation induced both a sustained increase in the external pH and sustained inhibition of the vanadate-sensitive ATPase. These results show that blue light inhibits the activity of the plasma membrane H(+)-ATPase. Inactivation of the plasma membrane H(+)-ATPase supports the membrane depolarization induced by the blue light irradiation.

The effect of light quality on ethylene production in leaves of oat seedlings ( Avena sativa L.)

The effect of UV, blue, green, red, far-red and white fluorescent lights at a fluence of 1.5–20 μmol m −2 s −1 photon flux density (PFD) on endogenous and ACC-dependent ethylene production by etiolated and green apical oat-leaf segments was investigated. It was found that endogenous ethylene production in light-irradiated green and etiolated oat leaves depends upon light quality and its fluence. All light of the visible spectrum (400–700 nm) at PFD 5–20 μmol m −2 s −1 reduced conversion of ACC to ethylene in green oat leaves incubated in 10 −3 M ACC. Blue light was most effective in the inhibition of ACC-dependent ethylene production at 5–10 μmol m −2 s −1 PFD, and endogenous ethylene formation at 10 μmol m −2 s −1 PFD. At 20 μmol m −2 s −1 PFD, all visible light wavebands substantially reduced endogenous ethylene production but blue and red light were most effective. In etiolated leaves UV at 1.5 μmol m −2 s −1 PFD, enhanced endogenous ethylene production and other lights at 20 μmol m −2 s −1 PFD decreased evolution of ethylene, whereas ACC-dependent ethylene formation was stimulated by UV, red and far-red wavebands. Growth of 10-day old seedlings was reduced by 40% under continuous blue light irradiation relative to that obtained with white light. Irradiation of etiolated and green leaf segments for 18 hr with blue light reduced ACC oxidase activity when compared to dark-treated ones. The influence of light quality and its fluence rate on the control of ethylene biosynthesis in oat leaves is discussed.

Prooxidant and antioxidant effects of ascorbate on photosensitized peroxidation of lipids in erythrocyte membranes.

Abstract— Continuous blue light irradiation of resealed erythrocyte ghosts at 37°C in the presence of uroporphyrin or protoporphyrin results in 1O2‐mediated (azide inhibitable) lipid peroxidation and membrane lysis. Lipid peroxidation was assessed by thiobarbituric acid reactivity and by quantitation of total hydroperoxides, while lysis was measured in terms of trappedglucose–6‐P release. Low concentrations of ascorbate, AH‐ (e.g. 0.5 mM). present at the start of irradiation, significantly enhanced the rates of lysis and peroxidation, whereas relatively high concentrations of AH‐ (e.g. 15 mM) inhibited both processes. By way of contrast. AH‐ produced only a dose‐dependent inhibition of the photoinactivation of lysozyme, added as an extramembranous target. No significant AH‐induced lipid peroxidation was observed in dark or light controls, plus porphyrin or minus porphyrin, respectively. Stimulation of peroxidation and lysis by low levels of AH‐ was enhanced by added Fe(III), abolished by EDTA. but unaffected by catalase or superoxide dismutase. A plausible explanation for these results is as follows. At low concentrations of AH‐ prooxidant activity is favored. Redox metal‐mediated breakdown of photoperoxides occurs, which tends to amplify lipid peroxidation. Neither O2‐ nor H2O2 appears to be involved. At significantly high concentrations, AH‐ acts predominantly as an antioxidant by intercepting 1O2 and/or sensitizer triplet, or by scavenging free radical intermediates of lipid peroxidation.

Lipid photooxidation in erythrocyte ghosts: Sensitization of the membranes toward ascorbate- and superoxide-induced peroxidation and lysis

The damaging effects of ascorbate (AH −) and superoxide (O 2 −) on resealed erythrocyte ghosts containing predetermined levels of lipid hydroperoxides (LOOHs) have been studied. Continuous blue light irradiation of membranes in the presence of protoprophyrin resulted in steadily increasing LOOH levels and enhanced release of a trapped marker, glucose 6-phosphate (G6P), after a 3- to 4-h lag. Neither superoxide dismutase (SOD) nor catalase inhibited these effects, ruling out O 2 − and H 2O 2 as reactive intermediates. A 1-h light dose produced partially photoperoxidized ghosts, which, in the dark at 37 °C, released G6P no faster than unirradiated controls (~7%/h). When xanthine oxidase plus xanthine (XO/X) was introduced as a source of O 2 − and H 2O 2, the irradiated membranes lysed rapidly ( t 1 2 ~ 2 h ). EDTA or SOD inhibited the reaction, whereas catalase had little or no effect. Unirradiated ghosts were not lysed by XO/X unless the system was supplemented with Fe(III), in which case total protection was afforded by SOD or catalase. In all experiments there was an excellent correlation between postirradiation lipid peroxidation (thiobarbituric acid reactivity) and G6P release. Similar observations were made with AH −. For example, dark incubation of photooxidized ghosts in the presence of 0.5 m m AH − resulted in rapid lysis ( t 1 2 ~ 1 h ), which was stimulated ~ twofold by 50 μ m Fe(III) and was inhibited by EDTA. By comparison, unirradiated ghosts showed no net peroxidation or lysis after 3 h exposure to Fe(III)/AH −. Neither SOD nor catalase protected against AH −-stimulated damage. AH − -promoted lipid peroxidation was inhibited by butylated hydroxytoluene, a lipophilic antioxidant, but was unaffected by 2,5-dimethylfuran or ethanol, singlet oxygen, and hydroxyl radical traps, respectively. These results suggest that a mechanism exists by which photogenerated LOOHs undergo redox metalmediated reduction to alkoxy radicals (LO •), which trigger a burst of membrane-disrupting lipid peroxidation.

Lysis of resealed erythrocyte ghosts by photoactivated tetrapyrroles: Estimation of photolesion dimensions

1. 1. Resealed erythrocyte ghosts containing Na + and glucose-6-P (G6P) as markers of membrane integrity were used as a model system for probing the damaging effects of photoactivated tetrapyrroles on cell membranes. 2. 2. Continuous blue-light irradiation of bilirubin (BR)-sensitized and protoporphyrin (PP)-sensitized ghosts made them progressively more permeable to Na + the cation emerging well ahead of G6P. 3. 3. G6P efflux occurred abruptly after a lag period and resembled an all-or-none process. 4. 4. These and other results suggest that a relatively subtle structural modification (possibly in some crucial protein(s) is sufficient for Na + release, whereas gross disruption of the bilayer (probably by free-radical lipid peroxidation) is necessary for G6P release. 5. 5. The dimensions of the G6P-releasing photolesions were estimated by density floatation centrifugation, using saccharides of increasing molecular size. Both BR and PP produced pores > 11 Å but <42 Å in diam, which is considerably smaller than the size range estimated in hypotonically lysed ghosts.