Display omitted
•A versatile recipe was proposed to obtain lattice oxygen vacancies in MnO2.•MnO2 with lattice oxygen vacancies shows enhanced elctrochemical perfromance.•The resultant LOV-MnO2 based ...cathode shows an excellent capacitance of 445.1 F g−1.•LOV-MnO2 based cathode renders capacitance retention of 96.6% after 10000-cycles.
Defect engineering has been considered as an efficient strategy to enhance the electrochemical performance of transition metal oxides based energy storage devices. However, the electrochemical activity and stability were greatly determined by the defect located crystal and external environments, which dominate the electrochemical properties of its based electrode. Thus, regulating a defect engineering recipe becomes a vital and direct route to advance the performance of the electrode materials. Herein, a versatile recipe combining the mild H-plasma and O-plasma was demonstrated for prototypical birnessite-MnO2 to achieve the robust lattice oxygen vacancies in birnessite-MnO2 (LOV-MnO2), targeting to boost its electrochemical energy storage performance. Theoretical calculation reveals the facilitated ion intercalation and diffusion kinetics due to the lower energy barrier in the LOV-MnO2. The LOV-MnO2 demonstrates an exceptional electrochemical performance with a specific capacitance as high as 445.1 F g−1 (at the current density of 1 A g−1), and the diffusion-controlled capacitance contribution reaches unprecedented ~70% (at a scan rate of 5 mV s−1). Besides, the configured symmetrical supercapacitor device LOV-MnO2//LOV-MnO2 delivers remarkable performance with an energy density of 92.3 Wh kg−1 at a power density of 1100.3 W kg−1 with a widen working voltage of 2.2 V. An outstanding cyclic life of 92.2% capacitance retention was also achieved after 10,000 charge–discharge cycles. Such superior electrochemical performance suggests that the proposed defect engineering recipes here will aid in the future development of advanced electrode materials for electrochemical energy storage devices.
Receptor tyrosine kinases (RTKs) are a large family of cell surface receptors that sense growth factors and hormones and regulate a variety of cell behaviours in health and disease. Contactless ...activation of RTKs with spatial and temporal precision is currently not feasible. Here, we generated RTKs that are insensitive to endogenous ligands but can be selectively activated by low‐intensity blue light. We screened light‐oxygen‐voltage (LOV)‐sensing domains for their ability to activate RTKs by light‐activated dimerization. Incorporation of LOV domains found in aureochrome photoreceptors of stramenopiles resulted in robust activation of the fibroblast growth factor receptor 1 (FGFR1), epidermal growth factor receptor (EGFR) and rearranged during transfection (RET). In human cancer and endothelial cells, light induced cellular signalling with spatial and temporal precision. Furthermore, light faithfully mimicked complex mitogenic and morphogenic cell behaviour induced by growth factors. RTKs under optical control (Opto‐RTKs) provide a powerful optogenetic approach to actuate cellular signals and manipulate cell behaviour.
Synopsis
A new method for spatially and temporally controlled activation of receptor tyrosine kinases (RTKs) is described. Bacterial LOV domains allow blue light‐activated dimerization of ligand‐insensitive FGFR, EGFR or RET receptors and mitogenic signalling.
Light‐oxygen‐voltage (LOV)‐sensing domains induce protein dimerization when activated by light.
Engineered FGFR1, EGFR and RET receptor tyrosine kinases that incorporate LOV domains self‐dimerize and get activated upon light exposure.
Light‐mediated activation of RTKs induces the respective endogenous downstream signalling pathways with high temporal and spatial resolution.
Light‐mediated activation of RTKs mimics complex cellular behaviours normally regulated by the physiological ligands of the RTKs.
A new method for spatially and temporally controlled activation of receptor tyrosine kinases is described. Bacterial LOV domains allow blue light‐activated dimerization of ligand‐insensitive FGFR, EGFR or RET receptors and mitogenic signalling.
Light-Oxygen-Voltage (LOV) proteins show considerable variation in the lifetime of the adduct state. Here, we used a comparative approach selecting two homologous LOV proteins originating from ...Pseudomonas fluorescens – SBW25-LOV and Pf5-LOV. At 37°C, SBW25-LOV and Pf5-LOV exhibit adduct state lifetimes of 1470 min and 3.6 min, respectively. The cartoon representation on the left shows the light-dependent global structural changes in the dimeric short LOV proteins of Pseudomonadaceae, such as the rotation of the core domains relative to each other and the increased distances at the N- and C-terminal junctions.
Display omitted
•Short LOV (Light, Oxygen, Voltage) proteins from Pseudomonas fluorescens.•Crystal structures of SBW25-LOV (fully light-adapted), and Pf5-LOV (dark) state.•Light-induced rotation of core domains and splaying of N- and C-terminal helices.•Three non-conserved residues identified as crucial for tuning dark recovery kinetics.•Signal transduction mechanisms among Pseudomonadaceae LOV proteins is conserved.
Light-Oxygen-Voltage (LOV) flavoproteins transduce a light signal into variable signaling outputs via a structural rearrangement in the sensory core domain, which is then relayed to fused effector domains via α-helical linker elements. Short LOV proteins from Pseudomonadaceae consist of a LOV sensory core and N- and C-terminal α-helices of variable length, providing a simple model system to study the molecular mechanism of allosteric activation. Here we report the crystal structures of two LOV proteins from Pseudomonas fluorescens - SBW25-LOV in the fully light-adapted state and Pf5-LOV in the dark-state. In a comparative analysis of the Pseudomonadaceae short LOVs, the structures demonstrate light-induced rotation of the core domains and splaying of the proximal A′α and Jα helices in the N and C-termini, highlighting evidence for a conserved signal transduction mechanism. Another distinguishing feature of the Pseudomonadaceae short LOV protein family is their highly variable dark recovery, ranging from seconds to days. Understanding this variability is crucial for tuning the signaling behavior of LOV-based optogenetic tools. At 37 °C, SBW25-LOV and Pf5-LOV exhibit adduct state lifetimes of 1470 min and 3.6 min, respectively. To investigate this remarkable difference in dark recovery rates, we targeted three residues lining the solvent channel entrance to the chromophore pocket where we introduced mutations by exchanging the non-conserved amino acids from SBW25-LOV into Pf5-LOV and vice versa. Dark recovery kinetics of the resulting mutants, as well as MD simulations and solvent cavity calculations on the crystal structures suggest a correlation between solvent accessibility and adduct lifetime.
This work proposes an automated strategy for the inorganic selenium speciation in infusion tea samples, employing an MSFIA-CVG-AFS system and sodium tetrahydroborate for chemical vapor generation. ...The selenium total is determined after an online prereduction step of selenium (VI) to selenium (IV) in alkaline media, using a UV reactor with a 15 W Hg lamp. Selenium (IV) is quantified directly on the sample, and selenium (VI) is determined by the difference between the total selenium and selenium (IV) concentrations. The optimization of the chemical parameters: hydrochloric acid – hydrobromide acid solution concentration, potassium iodide concentration, sodium hydroxide concentration, and sodium tetrahydroborate concentration was performed using a (24−1) two-level fractional factorial design. The validation parameters were determined for total selenium and selenium (IV), and the results found were: limits of detection and quantification of 0.05 and 0.18 μg L−1, respectively; a linear range of 0.18–5.0 μg L−1, precision expressed as the relative standard deviation of 2.1% for a sample number of 10, for both analytes. The system allows the speciation analysis with an injection throughput of 15 injections per hour. This analytical method was applied for inorganic selenium speciation in nine infusions of tea samples purchased commercially in supermarkets in Palma de Mallorca City, Spain. The concentrations of selenium (IV) and total selenium varied from 0.2 to 0.6 μg L−1 and 0.4–2.0 μg L−1, respectively. The accuracy method was evaluated using spike tests, and the recoveries achieved varied from 91 to 111%.
Display omitted
•A new system is proposed for inorganic selenium speciation in infusion tea samples using atomic fluorescence spectrometry.•This method do not requires any sample pre-treatment.•Selenium (IV) is quantified directly on the sample.•Total selenium is determined after an online pre-reduction to selenium (IV) using a UV reactor.•Selenium (VI) is determined by the difference between the total selenium and selenium (IV) concentrations.
The primary photochemistry is similar among the flavin‐bound sensory domains of light–oxygen–voltage (LOV) photoreceptors, where upon blue‐light illumination a covalent adduct is formed on the ...microseconds time scale between the flavin chromophore and a strictly conserved cysteine residue. In contrast, the adduct‐state decay kinetics vary from seconds to days or longer. The molecular basis for this variation among structurally conserved LOV domains is not fully understood. Here, we selected PpSB2‐LOV, a fast‐cycling (τrec 3.5 min, 20 °C) short LOV protein from Pseudomonas putida that shares 67% sequence identity with a slow‐cycling (τrec 2467 min, 20 °C) homologous protein PpSB1‐LOV. Based on the crystal structure of the PpSB2‐LOV in the dark state reported here, we used a comparative approach, in which we combined structure and sequence information with molecular dynamic (MD) simulations to address the mechanistic basis for the vastly different adduct‐state lifetimes in the two homologous proteins. MD simulations pointed toward dynamically distinct structural region, which were subsequently targeted by site‐directed mutagenesis of PpSB2‐LOV, where we introduced single‐ and multisite substitutions exchanging them with the corresponding residues from PpSB1‐LOV. Collectively, the data presented identify key amino acids on the Aβ‐Bβ, Eα‐Fα loops, and the Fα helix, such as E27 and I66, that play a decisive role in determining the adduct lifetime. Our results additionally suggest a correlation between the solvent accessibility of the chromophore pocket and adduct‐state lifetime. The presented results add to our understanding of LOV signaling and will have important implications in tuning the signaling behavior (on/off kinetics) of LOV‐based optogenetic tools.
The photocycle of light–oxygen–voltage (LOV) domains involves blue‐light‐triggered adduct formation between the bound flavin chromophore and a cysteine residue. LOV proteins show considerable variation in the lifetime of the adduct state. Here, we used a comparative approach selecting two homologous LOV proteins originating from Pseudomonas putida: a fast‐cycling PpSB2‐LOV (~ 3.5 min) and a slow‐cycling PpSB1‐LOV (~ 42 h) to investigate the mechanistic basis for the very different lifetimes of the adduct states.
Cells generate a highly diverse microtubule network to carry out different activities. This network is comprised of distinct tubulin isotypes, tubulins with different post-translational ...modifications, and many microtubule-based structures. Defects in this complex system cause numerous human disorders. However, how different microtubule subtypes in this network regulate cellular architectures and activities remains largely unexplored. Emerging tools such as photosensitive pharmaceuticals, chemogenetics, and optogenetics enable the spatiotemporal manipulation of structures, dynamics, post-translational modifications, and cross-linking with actin filaments in target microtubule subtypes. This review summarizes the design rationale and applications of these new approaches and aims to provide a roadmap for researchers navigating the intricacies of microtubule dynamics and their post-translational modifications in cellular contexts, thereby opening new avenues for therapeutic interventions.
Lånordet sharia, som i dag er i alminnelig bruk i svensk, dansk og norsk, har sitt opphav i det arabiske substantivet sharīʿa, med de beslektede formene substantivet sharʿa og verbet sharaʿa, som ...alle opptrer i koranteksten. Denne artikkelen tar for seg hvordan disse ordene er oversatt, definert, forklart og brukt i skandinaviske koranoversettelser og faglige fremstillinger, i et historisk perspektiv. I koranoversettelsene er ordene gjengitt semantisk med ulike betydninger knyttet til begreper som vei og retning eller terminologisk med vokabular fra et juridisk domene, og lånordet sharia er her fraværende. Frem til 1970-tallet var heller ikke lånordet særlig utbredt i faglitteraturen, men det ble etter hvert en del av et standardvokabular i fremstillinger av og diskusjoner omkring islam. I faglitteraturen varierer forståelsen mellom en legalistisk og en moralsk oppfatning av islams normative aspekter, og forklares gjennom begreper som lovreligion, etikk og hverdagsjuss.
Phototropin (phot) is a blue light photoreceptor in plants and possesses two photosensory light‑oxygen-voltage (LOV1 and LOV2) domains with different photo-thermochemical properties. While liverworts ...contain a single copy of PHOT (e.g., MpPHOT in Marchantia polymorpha), many land plant species contain multicopy PHOT genes (e.g., AtPHOT1 and 2 in Arabidopsis thaliana) due to evolutionary gene duplication. The LOV domains of duplicated phot proteins have been studied in detail, but those of single-copy phot proteins remain to be characterized. As phot has not been duplicated in liverworts, we hypothesized that Mpphot may retain the ancestral function and photo-thermochemical properties. To learn more about the unduplicated phot proteins, we analyzed chloroplast relocation movement and the photo-thermochemical properties of LOV1 and LOV2 in Mpphot (Mpphot-LOV1 and Mpphot-LOV2, respectively). The function of Mpphot-LOV1, which induced a response to move chloroplasts to weak light (the accumulation response) in the absence of photoactive LOV2, differed from that of LOV1 of the duplicated phot proteins of A. thaliana (e.g., Atphot1-LOV1 preventing the accumulation response). On the other hand, the function of Mpphot-LOV2 was similar to that of LOV2 of the duplicated phots. The photo-thermochemical properties of Mpphot were a hybrid of those of the duplicated phots; the photochemical and thermochemical reactions of Mpphot were similar to those of the phot2- and phot1-type proteins, respectively. Our findings reveal conservation and diversification among LOV domains during phot duplication events in land plant evolution.
•Photocycle of Marchantia phototropin (Mpphot) is a hybrid of duplicated phots.•Photoactivation property of Mpphot is similar to that of phot2-type receptor.•Thermochemical property of Mpphot is similar to that of phot1-type receptor.•Mpphot without LOV1 induces both chloroplast accumulation and avoidance responses.•Mpphot without LOV2 induces the accumulation response.
The principal aim of this paper was to investigate the roles of tourists' personality traits and personal values in shaping their travel motivation. Although previous literature has recognized these ...constructs as predictors of people's travel motivation, existing tourism literature lacks studies that combined tourists' personality, their personal values, and travel motivation within one research framework. Moreover, this paper contributes to existing tourism literature as it was the first to investigate the relationship between personality traits, measured with six personality factors (Big Five plus Honesty/Humility) and travel motivation. Specifically, the present study provides evidence on how the sixth trait - Honesty/Humility interacts with travel motivation. Besides, all nine investigated personal values were confirmed to positively influence travel motivation. Practical implications are discussed in the paper.
Studying dynamic biological processes requires approaches compatible with the lifetimes of the biochemical transactions under investigation, which can be very short. We describe a genetically encoded ...system that allows protein neighborhoods to be mapped using visible light. Our approach involves fusing an engineered flavoprotein to a protein of interest. Brief excitation of the fusion protein leads to the labeling of nearby proteins with cell-permeable probes. Mechanistic studies reveal different labeling pathways are operational depending on the nature of the exogenous probe that is employed. When combined with quantitative proteomics, this photoproximity labeling system generates "snapshots" of protein territories with high temporal and spatial resolution. The intrinsic fluorescence of the fusion domain permits correlated imaging and proteomics analyses, a capability that is exploited in several contexts, including defining the protein clients of the major vault protein. The technology should be broadly useful in the biomedical area.
PDF
