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Characterization and engineering of photoactivated adenylyl cyclases
摘要： Cyclic nucleoside monophosphates (cNMP) serve as universal second messengers in signal transduction across prokaryotes and eukaryotes. As signaling often relies on transiently formed microdomains of elevated second messenger concentration, means to precisely perturb the spatiotemporal dynamics of cNMPs are uniquely poised for the interrogation of the underlying physiological processes. Optogenetics appears particularly suited as it affords light-dependent, accurate control in time and space of diverse cellular processes. Several sensory photoreceptors function as photoactivated adenylyl cyclases (PAC) and hence serve as light-regulated actuators for the control of intracellular levels of 3′, 5′-cyclic adenosine monophosphate. To characterize PACs and to refine their properties, we devised a test bed for the facile analysis of these photoreceptors. Cyclase activity is monitored in bacterial cells via expression of a fluorescent reporter, and programmable illumination allows the rapid exploration of multiple lighting regimes. We thus probed two PACs responding to blue and red light, respectively, and observed significant dark activity for both. We next engineered derivatives of the red-light-sensitive PAC with altered responses to light, with one variant, denoted DdPAC, showing enhanced response to light. These PAC variants stand to enrich the optogenetic toolkit and thus facilitate the detailed analysis of cNMP metabolism and signaling.
关键词： synthetic biology,phytochrome,sensory photoreceptor,adenylyl cyclase,BLUF,optogenetics
更新于2025-09-23 15:22:29
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Simultaneously enhanced far-red luminescence and thermal stability in Ca3Al4ZnO10:Mn4+ phosphor via Mg2+ doping for plant growth lighting
摘要： Non-rare-earth-based Ca3Al4ZnO10:Mn4+,Mg2+ (CAZO:Mn4+,Mg2+) phosphors with admirable luminescence performance and great potential as far-red light source for plant growth light-emitting diodes (LEDs) were reported in this paper. The concentration-dependent optical properties of the as-prepared phosphors were investigated in detail. Under ultraviolet-light excitation at 358 nm, the composition-optimized CAZO:0.4%Mn4+,14%Mg2+ phosphor showed an intense broad far-red emission band in the 625-830 nm wavelength range with a maximum at 714 nm, which was due to the 2Eg→4A2g transition of Mn4+ ions. The luminescence intensity of the CAZO:0.4%Mn4+,14%Mg2+ phosphor was about 1.82 times higher than that of CAZO:0.4%Mn4+ phosphor, and the corresponding mechanism for the luminescence enhancement via Mg2+ doping was studied. Amazingly, the internal quantum efficiency of the CAZO:0.4%Mn4+ phosphor was increased from 31 to 60% after co-doping 14 mol% Mg2+. The CAZO:0.4%Mn4+,14%Mg2+ phosphor also showed enhanced thermal stability compared with the CAZO:0.4%Mn4+ counterpart. It was found that, for CAZO:0.4%Mn4+,14%Mg2+ phosphor, the emission intensity at 423 K (150 oC) was about 51% of that at 303 K (30 oC), while the corresponding activation energy was determined to be 0.245 eV.
关键词： thermal stability,plant growth,phytochrome,far-red emissions,LEDs.,Mn4+ ions
更新于2025-09-23 15:22:29
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A novel double-perovskite LiLaMgTeO6: Mn4+ far-red phosphor for indoor plant cultivation white LEDs: Crystal and electronic structure, and photoluminescence properties
摘要： Deep-red-emitting Mn4t activated oxide phosphors are the hot research topic due to their potential applications in indoor plant cultivation LEDs. In this paper, a novel double-perovskite LiLaMgTeO6:Mn4t phosphor was firstly prepared by high-temperature solid-state reaction method and its structure of the phosphor was determined by X-ray diffraction (XRD) and Rietveld refinement. Density functional theory (DFT) calculations using VASP provide an insight into the bandgap and electronic structures of the LiLaMgTeO6 host. Under UV or blue excitation, LiLaMgTeO6:Mn4t shows a good stability and bright far-red light in the 540e800 nm range with the maximum at 708 nm, which matches well with the absorption band of phytochrome PFR, indicating its potential application in improving plant growth. The optimal Mn4t doping concentration was approximately 0.6 mol%. Furthermore, a white-LEDs device made of a 365 nm chip coated with present phosphor and commercial green, blue phosphors was designed for indoor plant cultivation. The results indicate that the LiLaMgTeO6: Mn4t phosphor possesses great application prospect in white-LEDs for plant cultivation.
关键词： Far red emission,Phytochrome,Double perovskite,LEDs,Thermal stability,Indoor plant cultivation
更新于2025-09-23 15:21:01
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Effects of Far-Red LED Light on the Growth and Development of Tomato Seedlings in a Closed Seedling Production System
摘要： Year-round tomato cultivation needs high-quality seedlings with stem length and node position of the first flower truss controlled at suitable values. Generally, shade avoidance syndrome (SAS) promotes stem elongation and alters flowering time under natural sun- light. The objective of this study was to develop a method for controlling the stem elon- gation and flowering of tomato seedlings in a closed seedling production system (CSPS) with light emitting diodes (LEDs). We conducted two experiments to investigate how the artificial light environment induces SAS to control stem elongation and flowering. In Ex- periment 1, which examined the effect of end-of-day light (EOD-light), the phytochrome photostationary states (PSS) of the treatments were 0.56 for EOD-blue treatment, 0.89 for EOD-red (R) treatment, and 0.13 for EOD-far red (FR) treatment. Stem elongation was promoted more with EOD-FR treatment compared to the control. No significant differenc- es among the treatments were observed for the node position of the first flower truss. Therefore, although the EOD-FR treatment did not promote flowering, it did induce SAS. In Experiment 2, which examined the effect of FR light quantity in the CSPS, we repro- duced light environment conditions within the canopy at the time of the second nursery in a greenhouse and investigated how much the R/FR ratio induced SAS by adjusting the FR light quantity. The light environment conditions were tested at 150 nmol m-2 s-1 of total photosynthetic photon flux density with four FR light quantities (0, 50, 100, or 150 nmol m-2 s-1). There was no significant differences among the treatments for the node position of the first flower truss, and the stem elongation with FR50, FR100, and FR150 treatments was greater than that at FR0. These results suggested that the PSS, which was less than or equal to 0.72 during the light period (16 h), induced SAS. Thus, light environmental control with LEDs with EOD-FR or a low R/FR ratio is not suitable for the CSPS because it does not promote flowering of tomato seedlings.
关键词： red/far-red ratio,end-of-day far-red,phytochrome phytostationary state,morphogenesis
更新于2025-09-23 15:19:57
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Influence of the N-terminal segment and the PHY-tongue element on light-regulation in bacteriophytochromes
摘要： Photoreceptors enable the integration of ambient light stimuli to trigger lifestyle adaptations via modulation of central metabolite levels involved in diverse regulatory processes. Red light sensing bacteriophytochromes are attractive targets for the development of innovative optogenetic tools due to their natural modularity, diverse functionalities and the natural availability of the light-absorbing biliverdin in animal tissues. However, a rational design of such tools is complicated by the poor understanding of molecular mechanisms of light signal transduction over long distances – from the site of photon absorption to the active site of downstream enzymatic effectors. Here we show how swapping structural elements between two bacteriophytochrome homologs provides additional insights into light signal integration and effector regulation, involving a fine-tuned interplay of important structural elements of the sensor as well as the sensor-effector linker. Facilitated by the availability of structural information of inhibited and activated full-length structures of one of the two homologs (Idiomarina species A28L Phytochrome-activated diguanylyl Cyclase - IsPadC) and characteristic differences in photoresponses of the two homologs, we identify an important cross-talk between the N-terminal segment (NTS), containing the covalent attachment site of the chromophore, and the PHY-tongue region. Moreover, we highlight how these elements influence the dynamic range of photoactivation and how activation can be improved to light/dark ratios of ~800-fold by reducing basal dark-state activities at the same time as increasing photoconversion in the light-state. This will enable future optimization of optogenetic tools aiming at a direct allosteric regulation of enzymatic effectors.
关键词： phytochrome,diguanylate cyclase,photobiology,signal transduction,bilin,GGDEF,dimerization,photoreceptor
更新于2025-09-19 17:15:36
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[Methods in Molecular Biology] Vertebrate Embryogenesis Volume 1920 (Embryological, Cellular, and Genetic Methods) || Optogenetic Control of Subcellular Protein Location and Signaling in Vertebrate Embryos
摘要： This chapter describes the use of optogenetic heterodimerization in single cells within whole-vertebrate embryos. This method allows the use of light to reversibly bind together an “anchor” protein and a “bait” protein. Proteins can therefore be directed to specific subcellular compartments, altering biological processes such as cell polarity and signaling. I detail methods for achieving transient expression of fusion proteins encoding the phytochrome heterodimerization system in early zebrafish embryos (Buckley et al., Dev Cell 36(1):117–126, 2016) and describe the imaging parameters used to achieve subcellular light patterning.
关键词： Polarity,Heterodimerization,Signaling,Phytochrome,Optogenetics,Zebrafish
更新于2025-09-19 17:15:36
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Investigation of enhanced far-red emitting phosphor GdAlO3:Mn4+ by impurity doping for indoor plant growth LEDs
摘要： Phytochrome is indispensable for plant growth, which can absorb light useful for sprout, blossom, fruits. Generally, Phytochrome PR absorbs red light and Phytochrome PFR absorbs far-red light. The emission of Mn4+ doped GdAlO3 is situated in far-red light region. Herein, GdAlO3:Mn4+, Mg2+(GAL:Mn4+, Mg2+) phosphors were successfully synthesized via sol-gel method and the crystalline structure and luminescent properties were investigated systematically. Impressively, the emission intensity of GAL: Mn4+ phosphors was raised by Mg2+ and Ge4+ doping, and the mechanism of improved luminescence was also discussed. Depending on photoluminescence excitation and photoluminescence spectroscopy, the crystal field strength of the GdAlO3 host was calculated. In addition, excellent color purity and good thermal stability were found in Mg2+ co-doped GdAlO3:Mn4+ phosphors. Furthermore, the luminescence spectra of GAL: Mn4+, Mg2+ phosphor was agreed well with the absorption of Phytochrome PFR, which convincingly confirmed that Mg2+ co-doped GdAlO3:Mn4+ phosphors show promise in indoor plant growth LEDs.
关键词： indoor plant growth LEDs,far-red-emitting,Phytochrome PFR,Mn4+ luminescence
更新于2025-09-12 10:27:22
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Red light means on for phosphorus
摘要： Light is a critical environmental factor that influences nutrient uptake in roots and the subsequent use of nutrients, which is necessary to sustain plant growth. The positive effect of red light on phosphorus uptake has now been defined, along with the pivotal role of the phytochrome-B signalling cascades that mediate this effect.
关键词： nutrient uptake,phosphorus,red light,plant growth,phytochrome-B
更新于2025-09-10 09:29:36
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Bringing Light to Transcription: The Optogenetics Repertoire
摘要： The ability to manipulate expression of exogenous genes in particular regions of living organisms has profoundly transformed the way we study biomolecular processes involved in both normal development and disease. Unfortunately, most of the classical inducible systems lack fine spatial and temporal accuracy, thereby limiting the study of molecular events that strongly depend on time, duration of activation, or cellular localization. By exploiting genetically engineered photo sensing proteins that respond to specific wavelengths, we can now provide acute control of numerous molecular activities with unprecedented precision. In this review, we present a comprehensive breakdown of all of the current optogenetic systems adapted to regulate gene expression in both unicellular and multicellular organisms. We focus on the advantages and disadvantages of these different tools and discuss current and future challenges in the successful translation to more complex organisms.
关键词： transcription,optogenetics,cryptochrome,phytochrome B,LOV,gene expression,UVR8,light
更新于2025-09-09 09:28:46