Resonance Energy Research Articles

High-throughput screening of dual-target inhibitors for SARS-CoV-2 main protease and papain-like protease from Chebulae Fructus: in silico prediction and experimental verification

BackgroundThe unavoidable propagation of the coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has underscored the urgent requirement for efficacious therapeutic agents. The dried fruit of Terminalia chebula Retz., namely Chebulae Fructus, is widely used for treating bacterial and viral infectious diseases, which was witnessed to perform anti-SARS-CoV-2 activity in recommended Chinese patent medicine.AimSARS-CoV-2 main protease (Mpro) and papain-like protease (PLpro) present essential effects on SARS-CoV-2 replication and transcription, considering as the attractive targets for therapeutic intervention. In this study, we focused on the dual-target to obtain broad-spectrum antiviral candidates from Chebulae Fructus.MethodsThe identified compounds from Chebulae Fructus were used to build a library in a previous study, which were evaluated by molecular docking to screen potential antiviral agents. The SARS-CoV-2 Mpro and PLpro were expressed in E. coli cells and purified. Fluorescence resonance energy transfer (FRET) and surface plasmon resonance (SPR) were utilized to verify the affinity with dual targets. SARS-CoV-2 wild-type, Omicron BA.5 and Omicron EG.5 variants were employed to validate their antiviral activities in vitro. Molecular dynamics simulation was conducted via Gromacs 2022 software in 500 ns to unveil the conformation stability.ResultsTargeting on Mpro and PLpro, eight compounds were screened as the potential dual-target inhibitors in molecular docking. In FRET and SPR assays, 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG) and 1,2,3,6-tetra-O-galloyl-β-D-glucose (TGG) showed good inhibitory activities with IC50 values ranging from 1.33 to 27.37 μM, and affinity with KD values ranging from 0.442 to 0.776 μM. Satisfactorily, both PGG and TGG display antiviral activity in vitro with EC50 values ranging from 3.20 to 37.29 μM, suggesting as the promising candidates against SARS-CoV-2. In molecular dynamics simulation study, the complexes of Mpro-PGG, Mpro-TGG, PLpro-PGG, and PLpro-TGG exhibited stability over 500 ns period, unveiling the potential interactions.ConclusionPGG and TGG are the promising dual-target inhibitors of SARS-CoV-2, which may avoid drug resistance and have a good development prospect. The outcomes of this study provide an effective strategy to systematically explore the antiviral bioactive compounds from Chebulae Fructus.

High‐performance Ternary Organic Solar Cells With Spectral Uniform Photocurrent Generation by Enhanced Förster Resonance Energy Transfer Induced Reverse Hole Transfer

High‐performance Ternary Organic Solar Cells With Spectral Uniform Photocurrent Generation by Enhanced Förster Resonance Energy Transfer Induced Reverse Hole Transfer

Regulating Charge Separation Via Periodic Array Nanostructures for Plasmon-Enhanced Water Oxidation.

Plasmonic resonance intensity in metallic nanostructures plays a crucial role in charge generation and separation, directly affecting plasmon-induced photocatalytic activity. Engineering strategies to enhance plasmonic effects involve designing specific nanostructures, such as triangular nanoplates with sharp corners or dimer nanostructures with hot spots. However, these approaches often lead to a trade-off between enhanced plasmonic intensity and resonance energy, which ultimately determines local charge density and photocatalytic performance. Here, inspired by theoretical predications, it is shown that a flexibly controlled plasmonic photocatalyst, consisting of an ordered array of Au nanoparticles on a SrTiO3 surface, exhibits an enhanced surface plasmon resonance (SPR) intensity while maintaining a constant SPR resonant energy, due to the presence of surface lattice resonance. This trade-off results in improved charge separation efficiency and an increase in local charge density at catalytically active sites, as verified by theoretical simulations, surface photovoltage microscopy, and ultrafast transient absorption spectroscopy. Moreover, the optimized periodic photocatalyst shows a 7-fold increase in water oxidation activity over disordered nanostructures. This work provides a novel approach for balancing the intensity and energy of SPR, which will contribute to optimizing photocatalytic activity on plasmonic platforms.

Ligand-coupled conformational changes in a cyclic nucleotide-gated ion channel revealed by time-resolved transition metal ion FRET.

Cyclic nucleotide-binding domain (CNBD) ion channels play crucial roles in cellular-signaling and excitability and are regulated by the direct binding of cyclic adenosine- or guanosine-monophosphate (cAMP, cGMP). However, the precise allosteric mechanism governing channel activation upon ligand binding, particularly the energetic changes within domains, remains poorly understood. The prokaryotic CNBD channel SthK offers a valuable model for investigating this allosteric mechanism. In this study, we investigated the conformational dynamics and energetics of the SthK C-terminal region using a combination of steady-state and time-resolved transition metal ion Förster resonance energy transfer (tmFRET) experiments. We engineered donor-acceptor pairs at specific sites within a SthK C-terminal fragment by incorporating a fluorescent noncanonical amino acid donor and metal ion acceptors. Measuring tmFRET with fluorescence lifetimes, we determined intramolecular distance distributions in the absence and presence of cAMP or cGMP. The probability distributions between conformational states without and with ligand were used to calculate the changes in free energy (ΔG) and differences in free energy change (ΔΔG) in the context of a simple four-state model. Our findings reveal that cAMP binding produces large structural changes, with a very favorable ΔΔG. In contrast to cAMP, cGMP behaved as a partial agonist and only weakly promoted the active state. Furthermore, we assessed the impact of protein oligomerization and ionic strength on the structure and energetics of the conformational states. This study demonstrates the effectiveness of time-resolved tmFRET in determining the conformational states and the ligand-dependent energetics of the SthK C-terminal region.

Cross-Transition-Dipole Stacking of Conjugated Organic Molecules: Structure, Exciton Behavior and Optoelectronic Property.

Organic conjugated molecules have gained widespread application as organic semiconductors due to their unique optoelectronic properties. The rigidity of these large conjugated structures facilitates strong intermolecular interactions, which significantly influence their properties in the solid state through various molecular arrangements. The study of the relationship among molecular arrangement, exciton behavior, and optoelectronic properties is an eternal research topic. Cross-dipole stacking is a specific molecular arrangement that demonstrates unique characteristics and has received continuous attention over the past decades. This mini-review will first discuss the unique exciton behaviors in cross-dipole stacking based on exciton models, including weak exciton coupling and suppression of Förster resonance energy transfer. These exciton behaviors, determined by molecular stacking arrangements, are fundamental to the optoelectronic properties of cross-dipole stacking systems. Next, we will introduce well-defined cross-dipole systems and summarize their design principles from a molecular structure perspective. Finally, we will present the specific optoelectronic properties of cross-dipole stacking systems and their outstanding performance, such as high solid-state luminescence, good charge carrier mobility, and significant CD/CPL. Through this mini-review, we hope to enhance the understanding of cross-dipole stacking, contributing to the construction of such systems, the exploration of excited-state behaviors, and the discovery of high-performance materials.

PH-Responsive Persistent Luminescent Nanosystem with Sensitized NIR Imaging and Ratiometric Imaging Modes for Tumor Surgery Navigation.

Owing to autofluorescence-free feature, persistent luminescent (PersL) nanoparticles (PLNPs) become potential materials for tumor surgical navigation. However, it is still challenging to enhance PersL intensity, contrast ratio, and imaging stability so as to meet clinical demand and avoid missed detection of microlesions. Herein, integrating a tumor microenvironment (TME)-responsive strategy, sensitization enhancement, and internal-standard ratiometric method, a dual-mode PersL imaging strategy is proposed: After loading pH-responsive fluorescent molecule Rh-ADM on PLNPs ZnGa2O4:Cr3+,Mn2+ (ZGCM-Rh8), the fluorescence resonance energy transfer (FRET) pathways between Cr3+ and Rh-ADM, as well as Mn2+ and Rh-ADM, could sensitize the NIR PersL emitted by Cr3+ and quench the green PersL from Mn2+ at acidic TME, respectively. As a result, ZGCM-Rh8 is endowed with WLED (white light LED)-excited NIR imaging mode and UV-excited ratiometric imaging mode. Under WLED, ZGCM-Rh8 realizes 4.5-fold PersL enhancement and 97.9 as the maximum tumor contrast after precise control of Rh-ADM contents, helping with the preoperative diagnosis of deep lesions. Under UV, ZGCM-Rh8 conducts ratiometric PersL imaging steadily, and the "NIR/Vis" ratios at the tumor keep larger than 110, succeeding in detecting out a 1.5 mm small lesion and serving thorough surgical elimination of H22 ectopic intramuscular tumor in balb/c mice. To our knowledge, ZGCM-Rh8 is the first to realize pH-responsive PersL sensitization and apply ratiometric PersL imaging technology to surgical navigation.

A Novel Turn‐On Fluorescence Probe for Selective Picomolar Detection of Uric Acid Using Green Carbon Dots (G‐NCDs) from Waste Brachyura Shells

AbstractIn the current study, a Novel synthesis of fluorescent Green carbon dots (G‐NCDs) is reported from waste Brachyura shells using a simple, green technique. G‐NCDs function as a TURN‐ON fluorescent probe for the selective detection Uric Acid (UA) in presence of Dopamine (DA). The synthesized carbon dots are sand colored under visible light and exhibit pale green fluorescence under UV radiation. The G‐NCDs are characterized using UV–vis, FTIR, XPS, SEM‐EDAX, HR‐TEM, X‐ray diffraction, and PL spectroscopic technique. The SEM‐EDAX data of G‐NCDs shows a layered, fibrous morphology and confirms the presence of only Carbon, Nitrogen, and Oxygen in the matrix. FTIR and XPS response confirms the presence of functional groups like ─C≡N, ─C≡C─, CH, ═C─H, O─H on the surface of G‐NCDs. XRD data confirms G‐NCDs to be crystalline with a particle size of 4.51 nm. The quantum yield found to be 99.8%. PL response confirms a TURN OFF fluorescence with increased addition of DA. Fluorescence resonance energy transfer (FRET), a form of dynamic quenching is responsible for the DA quenching, confirmed through linear Stern‐ Volmer plot. With increase in addition of UA in presence of DA fluorescence TURNs ON with a minimum selective detection limit of UA as 0.23 × 10−12 M. Selective detection of UA in presence of DA is due to the following reasons i) decrease in bandgap of G‐NCDs in presence of UA ii) electrostatic attraction between negatively charged carboxyl group of G‐NCDs and positively charge secondary amine group of UA molecule ii) UA molecules near to the surface of G‐NCDs switches off the formation of polydopamine iv) formation of surface defects due to the formation of hydrogen bonds between the ketone/hydroxyl group in the UA molecule and the amino group on the surface of G‐NCD resulting in fluorescence. The first time the lowest detection limit of 0.23 × 10−12 M of UA is been reported in presence of DA using G‐NCDs. In future, G‐NCDs will be used for the detection of UA in biological fluids.

SmCamera: all-in-one software package for single-molecule data acquisition and data analysis

AbstractIn the last decades, biological applications of single-molecule methods have grown rapidly and researchers with expertise in microscopy and instrumentation have adopted these techniques and advanced them even further. However, practicing single-molecule methods is still challenging for most because of the need for expensive equipments and instrumentation demands as well as complicated data acquisition and analysis workflow consisting of multiple steps using different software in each of them. smCamera is an all-in-one software package which aims to alleviate steep learning curves of the data acquisition and analysis. From recording movies through extraction of time series of single-molecule fluorescence resonance energy transfer (smFRET), everything can be done in a single program without any additional software or programming languages. Although smCamera has not been published before, it has been distributed to facilitate adaption of smFRET experiments and there has been requests for support for this software. We hope that this work answers questions from researchers using smCamera and also provides an opportunity to introduce and distribute smCamera for new users.

Photoluminescent Sol‐Gel Glass Constructed via Highly Efficient Förster Resonance Energy Transfer

AbstractPhotoluminescent (PL) solid with color tunability are in high demand for the development of large‐area display and illumination devices. With high transparency, high chemical stability, and mature fabrication, sol‐gel glass is an ideal solid matrix to obtain such materials by chromophore doping. However, it remains a big challenge to obtain sol‐gel glass with high luminous efficiency under a single excitation wavelength. Herein, the construction of highly luminescent sol‐gel glass enabled by Förster resonance energy transfer (FRET) is reported. Branched siloxane is used to modify naphthalene and BODIPY, which led to the formation of blue‐emitting donor (denoted as Si‐Nap) and green‐emitting acceptor (denoted as Si‐BODIPY), respectively. Efficient FRET occurs between Si‐Nap and Si‐BODIPY proved by spectral titration and lifetime measurements, with an energy transfer efficiency (ΦET) up to 97.9%. When RhB is added, it acts as a final acceptor that enables the occurrence of a sequential FRET from Si‐Nap to Si‐BODIPY and further to RhB. The overall energy transfer efficiency reaches 94%, and the fluorescence quantum yield exceeds 88%. By adjustment of the composition, color‐tunable sol‐gel glass is obtained with emergence of white‐emitting samples, opening potential applications in a variety of fields.

A genetically encoded anomalous SAXS ruler to probe the dimensions of intrinsically disordered proteins

Intrinsically disordered proteins (IDPs) adopt ensembles of rapidly fluctuating heterogeneous conformations, influencing their binding capabilities and supramolecular transitions. The primary conformational descriptors for understanding IDP ensembles-the radius of gyration (RG), measured by small-angle X-ray scattering (SAXS), and the root mean square (rms) end-to-end distance (RE), probed by fluorescent resonance energy transfer (FRET)-are often reported to produce inconsistent results regarding IDP expansion as a function of denaturant concentration in the buffer. This ongoing debate surrounding the FRET-SAXS discrepancy raises questions about the overall reliability of either method for quantitatively studying IDP properties. To address this discrepancy, we introduce a genetically encoded anomalous SAXS (ASAXS) ruler, enabling simultaneous and direct measurements of RG and RE without assuming a specific structural model. This ruler utilizes a genetically encoded noncanonical amino acid with two bromine atoms, providing an anomalous X-ray scattering signal for precise distance measurements. Through this approach, we experimentally demonstrate that the ratio between RE and RG varies under different denaturing conditions, highlighting the intrinsic properties of IDPs as the primary source of the observed SAXS-FRET discrepancy rather than shortcomings in either of the two established methods. The developed genetically encoded ASAXS ruler emerges as a versatile tool for both IDPs and folded proteins, providing a unified approach for obtaining complementary and site-specific conformational information in scattering experiments, thereby contributing to a deeper understanding of protein functions.

A facile optical fiber-embedded microfluidic biochip for rapid and sensitive detection of microRNA-let-7a in serum.

Anovel hybridization chain reaction (HCR) powered optical fiber-embedded microfluidic biochip (HCR-FMB) has been constructed for ultrafast and sensitive detection of lethal-7a (let-7a) in serum. By integrating HCR, fluorescence energy resonant transfer, and evanescent wave fluorescence principle, the HCR-FMB enables detecting let-7a with satisfactory limit of detection of 100.0 pM within 6min at room temperature, and demonstrates excellent specificity. TheHCR-FMB can directly detect let-7a in serum with high sensitivity and without any pre-treatment, and good recoverieswere observed for let-7a in serum samples, demonstrating their potential application tothe analysis of serum samples. The HCR-FMB exhibits several advantages, including rapidity, enzyme-free, miniaturization, ease-of-operation, field-deployment applicability, minimal-equipment, and cost-effectiveness. The HCR-FMB can be considered arevolutionary detection device that rapidly adapts and deploys in various settings, especially in low medical resource regions.

Nature of the Nickel-Halogen Bond in NiX+ Compounds (X = F, Cl, Br, I): A Multireference Configuration Interaction and Ab Initio Valence Bond Study.

In a recent study (Inorg. Chem. 2024, 63, 11812-11820), gas-phase cationic NiX+ compounds (X = F, Cl, Br, and I) were probed by nickel L-edge XAS, from which it was concluded that NiF+ was best described as an ionic [Ni2+F-]+ complex while the remaining three compounds were described as covalent Ni(3d9)L species (L depicts a ligand-based hole). An abrupt transition from a classical to an inverted ligand field was suggested as responsible for the change in ground-state electronic structures. Herein, the NiX+ series is investigated by using MRCI and ab initio VB calculations. Nickel L-edge X-ray absorption spectra were also modeled within a ROCIS formalism. It was found that all four compounds possess normal ligand fields and nominal Ni(3d9) electron counts. Furthermore, it was found that the dominant bonding interactions in NiF+ and NiCl+ are two 2-center/3-electron (2c/3e) bonds, while in NiBr+ and NiI+ the dominant bonding interactions are one Ni-X covalent bond and one 2c/3e bond. The change in bonding interactions between NiF+/NiCl+ vs NiBr+/NiI+ was rationalized by considering the marked decrease in resonance energy that stabilizes the 2c/3e bond for the heavier halide congeners, which results from the disparity in electronegativities between the nickel-center and the heavier halides.

Tunable Nano-Supramolecules Based on Cucurbiturils for Near-Infrared Phosphorescence Imaging.

Nano-supramolecules based on artificial macrocycles can not only regulate assembly morphology but also boost phosphorescence resonance energy transfer (PRET). Herein, a water-soluble phosphorescence supramolecule was constructed from the hyaluronic acid-modified bromophenylpyridinium (HAPY), cucurbit[n]uril (CB[n], n = 7/8), and energy acceptor phenyl-bridged phenothiazine derivatives, displaying efficient PRET and achieving near-infrared (NIR) phosphorescence by macrocyclic CB[n] and the assembly confinements. As compared with weak phosphorescent nanofibers of HAPY/CB[7], the spherical nanoparticles of HAPY/CB[8] not only gave strong green phosphorescence with extended lifetime to 1.27 ms but also could act as the energy donor and confine cationic phenothiazine in the secondary assemblies, leading to highly efficient PRET efficiency (87.27%) from the phosphors to triplet acceptors, realizing phosphorescence emission at 750 nm and an ultralarge Stokes shift of 440 nm. Ultimately, the nanoassembly achieved by the multiscale confinements boosting PRET was successfully applied in targeted cancer cell imaging, providing new insight for fabricating NIR phosphorescence materials.

Förster Resonance Energy Transfer in Metal Halide Perovskite: Current Status and Future Prospects.

Förster Resonance Energy Transfer (FRET) is a non-radiative energy transfer process in a donor-acceptor system and has applications in various fields, such as single-molecule investigations, biosensor creation, and deoxyribonucleic acid (DNA) mechanics research. The investigation of FRET processes in metal halide perovskites has also attracted great attention from the community. The review aims to provide an up-to-date study of FRET in the context of perovskite systems. First, we discuss the fundamentals of FRET process, and then summarize the recent progress of FRET phenomenon in perovskite-perovskite, perovskite-inorganic fluorophores, perovskite-organic fluorophores, and organic fluorophores-perovskite systems. Finally, we speculate on the future prospects of roles of FRET in the implications for the overall performance of optoelectronic devices based on these systems, as well as the challenges in maximizing FRET efficiency.

Effect of Confinement on the Translational Diffusivity of Small Dye Molecules in Thin Polystyrene Films and Its Connection to Tg-Confinement and Fragility-Confinement Effects.

Using fluorescence, we study the impact of nanoscale confinement on the translational diffusivity (D) of trace levels of a small-molecule dye, 9,10-bis(phenylethynyl)anthracene (BPEA), in supported polystyrene (PS) films via Förster resonance energy transfer (FRET). Reductions in BPEA diffusivity are observed in films thinner than ∼200 nm, with D decreasing by 80-90% in 100 nm-thick films compared to bulk. The activation energy of BPEA diffusivity increases from ∼210 kJ/mol in bulk films to ∼370 kJ/mol in 130 nm-thick films. BPEA exhibits a greater diffusivity-confinement effect than a larger dye, decacyclene, in terms of the length scale at which the effects of confinement become evident and the percentage reduction in diffusivity. For both BPEA and decacyclene, the diffusivity-confinement effect in supported PS films occurs at a length scale much larger than that for the glass transition temperature (Tg)-confinement effect and somewhat larger than that for the fragility-confinement effect. This difference in confinement-effect length scales can be rationalized as follows: small-molecule dye diffusivity relates predominantly to short times in the α-relaxation distribution, whereas Tg relates to long times in the α-relaxation distribution, and fragility reflects the overall breadth of this relaxation time distribution. If confinement results in a narrower relaxation time distribution in PS films with the short-time relaxations being shifted to longer times and the longest-time relaxation regimes being shifted to shorter times, then Tg, diffusivity, and fragility all decrease at sufficient levels of confinement. If the narrowing with confinement begins with the shortest relaxation time regimes, then fragility and small-molecule dye diffusivity are influenced by confinement at larger length scales than Tg.

Indication of p + 11B reaction in Laser Induced Nanofusion experiment

The NanoPlasmonic Laser Induced Fusion Energy (NAPLIFE)1 project proposed fusion by regulating the laser light absorption via resonant nanorod antennas implanted into hydrogen rich urethane acrylate methacrylate (UDMA) and triethylene glycol dimethylacrylate (TEGDMA) copolymer targets. In part of the tests, boron-nitride (BN) was added to the polymer. Our experiments with resonant nanoantennas accelerated protons up to 225 keV energy. Some of these protons then led to p + 11B fusion, indicated by the sharp drop of observed backward proton emission numbers at the 150 keV resonance energy of the reaction. The generation of alpha particles was verified by CR-39 (Columbia Resin #39) nuclear plastic track detectors.

Ligand response of guanidine-IV riboswitch at single-molecule level

Riboswitches represent a class of non-coding RNA that possess the unique ability to specifically bind ligands and, in response, regulate gene expression. A recent report unveiled a type of riboswitch, known as the guanidine-IV riboswitch, which responds to guanidine levels to regulate downstream genetic transcription. However, the precise molecular mechanism through which the riboswitch senses its target ligand and undergoes conformational changes remain elusive. This gap in understanding has impeded the potential applications of this riboswitch. To bridge this knowledge gap, our study investigated the conformational dynamics of the guanidine-IV riboswitch RNA upon ligand binding. We employed single-molecule fluorescence resonance energy transfer (smFRET) to dissect the behaviors of the aptamer, terminator, and full-length riboswitch. Our findings indicated that the aptamer portion exhibited higher sensitivity to guanidine compared to the terminator and full-length constructs. Additionally, we utilized Position-specific Labelling of RNA (PLOR) combined with smFRET to observe, at the single-nucleotide and single-molecule level, the structural transitions experienced by the guanidine-IV riboswitch during transcription. Notably, we discovered that the influence of guanidine on the riboswitch RNA’s conformations was significantly reduced after the transcription of 88 nucleotides. Furthermore, we proposed a folding model for the guanidine-IV riboswitch in the absence and presence of guanidine, thereby providing insights into its ligand-response mechanism.

Ligand response of guanidine-IV riboswitch at single-molecule level.

Riboswitches represent a class of non-coding RNA that possess the unique ability to specifically bind ligands and, in response, regulate gene expression. A recent report unveiled a type of riboswitch, known as the guanidine-IV riboswitch, which responds to guanidine levels to regulate downstream genetic transcription. However, the precise molecular mechanism through which the riboswitch senses its target ligand and undergoes conformational changes remain elusive. This gap in understanding has impeded the potential applications of this riboswitch. To bridge this knowledge gap, our study investigated the conformational dynamics of the guanidine-IV riboswitch RNA upon ligand binding. We employed single-molecule fluorescence resonance energy transfer (smFRET) to dissect the behaviors of the aptamer, terminator, and full-length riboswitch. Our findings indicated that the aptamer portion exhibited higher sensitivity to guanidine compared to the terminator and full-length constructs. Additionally, we utilized Position-specific Labelling of RNA (PLOR) combined with smFRET to observe, at the single-nucleotide and single-molecule level, the structural transitions experienced by the guanidine-IV riboswitch during transcription. Notably, we discovered that the influence of guanidine on the riboswitch RNA's conformations was significantly reduced after the transcription of 88 nucleotides. Furthermore, we proposed a folding model for the guanidine-IV riboswitch in the absence and presence of guanidine, thereby providing insights into its ligand-response mechanism.

Spatial heterogeneity accelerates phase-to-trigger wave transitions in frog egg extracts

Cyclin-dependent kinase 1 (Cdk1) activity rises and falls throughout the cell cycle: a cell-autonomous process called mitotic oscillations. Mitotic oscillators can synchronize when spatially coupled, facilitating rapid, synchronous divisions in large early embryos of Drosophila (~0.5 mm) and Xenopus (~1.2 mm). Diffusion alone cannot achieve such long-range coordination. Instead, studies proposed mitotic waves—phase and trigger waves—as mechanisms of the coordination. How waves establish over time remains unclear. Using Xenopus laevis egg extracts and a Cdk1 Förster resonance energy transfer sensor, we observe a transition from phase to trigger wave dynamics in initially homogeneous cytosol. Spatial heterogeneity promotes this transition. Adding nuclei accelerates entrainment. The system transitions almost immediately when driven by metaphase-arrested extracts. Numerical simulations suggest phase waves appear transiently as trigger waves take time to entrain the system. Therefore, we show that both waves belong to a single biological process capable of coordinating the cell cycle over long distances.

A FRET probe based on flavonol-benzothiazole for the detection of viscosity and SO2 derivatives

Sulfur dioxide (SO2) and viscosity play important roles in living organisms, and abnormal levels of them are associated with many diseases. Hence, a bifunctional fluorescence probe (E)-3-(2-(4-(4-(4-(6-fluoro-3-hydroxy-4-oxo-4H-chromen-2-yl)benzoyl)piperazin-1-yl)styryl)benzo-[d]thiazol-3-ium-3-yl)propane-1-sulfonate (HFBT) with fluorescence resonance energy transfer (FRET) properties was successfully constructed by using 3-hydroxyflavonol as the energy donor and benzothiazole sulphonate derivatives as the energy acceptor, and it can be used for the detection of SO2 derivatives (HSO3−/HSO32−) and viscosity. HFBT exhibits a large Stokes shift (245 nm), high resonance energy transfer efficiency (95.56 %), and excellent selectivity, anti-interference and low limit of detection (LOD = 0.057 μM) for HSO3−. The fluorescence intensity of HFBT at 608 nm gradually increases with the increase of viscosity. Interestingly, a visual HSO3− detection platform was successfully constructed and applied to the quantitative detection of HSO3− in food. Additionally, HFBT was successfully applied to imaging endogenous and exogenous HSO3− in cells. The successful development of HFBT provides an effective tool for the detection and imaging of HSO3− in food and cells.