Project description:Light quality is an important abiotic factor that affects growth and development of photosynthetic organism. In this study, D. salina was exposed to red (660 nm) and blue light (450 nm), and cell growth, pigments, and transcriptome were analyzed. The RNA of D. salina was sequenced and transcriptomic response of algal cells after transitioning from white light to red and blue light was investigated. Genes encoding for enzymes involved in photosynthesis were down-regulated, whereas genes involved in the metabolism of carotenoid were up-regulated. Genes encoding for photoprotective enzymes related to reactive oxygen species scavenging were up-regulated under both red and blue light. The present transcriptomic study would assist in the comprehensive understanding of carotenoid biosynthesis of D. salina.
Project description:The cyanobacterial phytochrome Cph2 is a light-dependent diguanylate cyclase producing the second messenger c-di-GMP. Under blue light, the Cph2-dependent increase in the cellular c-di-GMP concentration leads to inhibition of motility in the cyanobacterium Synechocystis 6803. However, the targets of c-di-GMP in this cyanobacterium and its mechanism of action remained unclear. Here, we determined the cellular concentrations of three cyclic nucleotides in wild-type and Δcph2 cells after blue- and green light illumination. Inactivation of the photoreceptor gene completely abolished the blue-light dependent increase in the c-di-GMP content. Microarray analysis revealed that in the wild type in comparison to the Δcph2 mutant, blue light mainly led to a change in accumulation of mRNAs encoding minor pilins, putative chaperone usher pili as well as several chemotaxis regulators. The mRNA encoding the minor pilins pilA5-pilA6 is negatively affected by high c-di GMP content under blue light, whereas the minor pilin encoding operon pilA9-slr2018 accumulates under the same conditions, suggesting opposing functions of the respective gene sets. Based on mutational and gene expression analysis, we further suggest that the second Synechocystis 6803 homolog of a CRP-like transcription factor, SyCRP2, is the regulator of minor pilin gene expression and of putative chaperone usher pili genes slr1667/slr1668. Thus, our work indicates that the Cph2-mediated increase in cellular c-di-GMP concentration upon blue-light illumination specifically changes the transcriptome of Synechocystis 6803.
Project description:Lycopene content significantly increased in pulsed light-treated tomatoes. Proteomic analysis identified 1046 differentially expressed proteins (DEPs). Multi-omics analyses revealed that the gene expression, protein accumulation, and metabolite levels in the carotenoid biosynthesis pathway of tomatoes were coordinately upregulated after pulsed light treatment, with particularly significant activation of pathways related to the tricarboxylic acid (TCA) cycle, terpenoid backbone biosynthesis, and photosynthesis-antenna proteins. The findings indicated that the reprogramming of energy metabolism (including oxidative phosphorylation and carbon fixation pathways) and the synthesis of secondary metabolites (such as porphyrin metabolism and glutathione metabolism) played crucial roles in lycopene accumulation induced by pulsed light. These differential molecules were significantly enriched in pathways including terpenoid backbone biosynthesis, carotenoid biosynthesis, the tricarboxylic acid (TCA) cycle, and photosynthesis.
Project description:Photobiomodulation (PBM) with blue light induces a biphasic dose response curve in proliferation of immortalized human keratinocytes (HaCaT), with a maximum anti-proliferative effect reached with 30min (41.4J/cm²). The aim of this study was to test the photobiomodulatory effect of 41.4J/cm2 blue light irradiation on ROS production, apoptosis and gene expression at different time points after irradiation of HaCaT cells in vitro. ROS concentration was increased 30min after irradiation. However, already 1h after irradiation, cells were able to reduce ROS and balance the concentration to a normal level. The sudden increase in ROS did not damage the cells, which was demonstrated with FACS analysis where HaCaT cells did not show any sign of apoptosis after blue light irradiation. Furthermore, a time course could be seen in gene expression analysis after blue light, with an early response of stimulated genes already 1h after blue light irradiation, leading to the discovery of the aryl hydrocarbon receptor as possible target for blue light irradiation.
Project description:Photobiomodulation (PBM) with blue light induces a biphasic dose response curve in proliferation of immortalized human keratinocytes (HaCaT), with a maximum anti-proliferative effect reached with 30min (41.4J/cm²). The aim of this study was to test the photobiomodulatory effect of 41.4J/cm2 blue light irradiation on ROS production, apoptosis and gene expression at different time points after irradiation of HaCaT cells in vitro. ROS concentration was increased 30min after irradiation. However, already 1h after irradiation, cells were able to reduce ROS and balance the concentration to a normal level. The sudden increase in ROS did not damage the cells, which was demonstrated with FACS analysis where HaCaT cells did not show any sign of apoptosis after blue light irradiation. Furthermore, a time course could be seen in gene expression analysis after blue light, with an early response of stimulated genes already 1h after blue light irradiation, leading to the discovery of the aryl hydrocarbon receptor as possible target for blue light irradiation.
Project description:Photobiomodulation (PBM) with blue light induces a biphasic dose response curve in proliferation of immortalized human keratinocytes (HaCaT), with a maximum anti-proliferative effect reached with 30min (41.4J/cm²). The aim of this study was to test the photobiomodulatory effect of 41.4J/cm2 blue light irradiation on ROS production, apoptosis and gene expression at different time points after irradiation of HaCaT cells in vitro. ROS concentration was increased 30min after irradiation. However, already 1h after irradiation, cells were able to reduce ROS and balance the concentration to a normal level. The sudden increase in ROS did not damage the cells, which was demonstrated with FACS analysis where HaCaT cells did not show any sign of apoptosis after blue light irradiation. Furthermore, a time course could be seen in gene expression analysis after blue light, with an early response of stimulated genes already 1h after blue light irradiation, leading to the discovery of the aryl hydrocarbon receptor as possible target for blue light irradiation.
Project description:Light is one of the main environmental cues that affects the physiology and behavior of many organisms. The effect of light on genome-wide transcriptional regulation has been well-studied in green algae and plants, but not in red algae. Cyanidioschyzon merolae is used as a model red algae, and is suitable for studies on transcriptomics because of its compact genome with a relatively small number of genes. In addition, complete genome sequences of the nucleus, mitochondrion, and chloroplast of this organism have been determined. Together, these attributes make C. merolae an ideal model organism to study the response to light stimuli at the transcriptional and the systems biology levels. Previous studies have shown that light significantly affects cell signaling in this organism, but there are no reports on its blue light- and red light-mediated transcriptional responses. We investigated the direct effects of blue and red light at the transcriptional level using RNA-seq. Blue and red light were found to regulate 35% of the total genes in C. merolae. Blue light affected the transcription of genes involved protein synthesis while red light specifically regulated the transcription of genes involved in photosynthesis and DNA repair. Blue or red light regulated genes involved in carbon metabolism and pigment biosynthesis. Overall, our data showed that red and blue light regulate the majority of the cellular, cell division, and repair processes in C. merolae.
Project description:Light is one of the main environmental cues that affects the physiology and behavior of many organisms. The effect of light on genome-wide transcriptional regulation has been well-studied in green algae and plants, but not in red algae. Cyanidioschyzon merolae is used as a model red algae, and is suitable for studies on transcriptomics because of its compact genome with a relatively small number of genes. In addition, complete genome sequences of the nucleus, mitochondrion, and chloroplast of this organism have been determined. Together, these attributes make C. merolae an ideal model organism to study the response to light stimuli at the transcriptional and the systems biology levels. Previous studies have shown that light significantly affects cell signaling in this organism, but there are no reports on its blue light- and red light-mediated transcriptional responses. We investigated the direct effects of blue and red light at the transcriptional level using RNA-seq. Blue and red light were found to regulate 35% of the total genes in C. merolae. Blue light affected the transcription of genes involved protein synthesis while red light specifically regulated the transcription of genes involved in photosynthesis and DNA repair. Blue or red light regulated genes involved in carbon metabolism and pigment biosynthesis. Overall, our data showed that red and blue light regulate the majority of the cellular, cell division, and repair processes in C. merolae.
Project description:UV-A mediated regulation of anthocyanin biosynthesis was investigated in swollen hypocotyls of the red turnip ‘Tsuda’. The shaded swollen hypocotyls which contained negligible anthocyanin were exposed to artificial light sources including low fluence UV-B, UV-A, blue, red, far-red, red plus UV-A, far-red plus UV-A, and blue plus red. Among these lights, only UV-A induced anthocyanin biosynthesis and co-irradiation of red or far-red with UV-A did not affect the extent of UV-A induced anthocyanin accumulation. The expression of phenylalanine ammonia lyase (PAL; EC 4.3.1.5), chalcone synthase (CHS; EC 2.3.1.74), flavanon 3-hydrocylase (F3H; EC 1.14.11.9), dihydroflavonol 4-reductase (DFR; EC 1.1.1.219) and anthocyanidin synthase (ANS; EC 1.14.11.-) genes were increased with time during a 24 hour exposure of UV-A. In contrast, irradiation of red, blue, UV-B, and a combination of blue with red failed to induce CHS expression. Microarray analysis showed that only a few genes, including chalcone synthase and flavanon 3-hydroxylase were induced significantly by UV-A, while a separate set of many genes was induced by low fluence UV-B. The UV-A specific induction of anthocyanin biosynthesis and the unique gene expression profile upon UV-A irradiation as compared with blue and UV-B demonstrated that the observed induction of anthocyanin biosynthesis in red turnips was mediated by a distinct UV-A specific photoreceptor, but not by phytochromes, UV-A/blue photoreceptors, or UV-B photoreceptors. Keywords: light response