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The “Nobel Prize in Chemistry 2023” is awarded to Moungi G. Bawendi, Louis E. Brus, and Alexey I. Yekimov for discovering and synthesizing Quantum Dots (QDs). Colloidal QDs possess fascinating size‐, morphological‐, composition‐, and assembly‐tunable electronic and optical properties, which makes them star materials for various optoelectronic applications, especially as luminescent materials for next‐generation wide color gamut ultra‐high‐definition displays. Perovskite QDs (PQDs) have gained widespread attention in recent years. In less than ten years, research on perovskite‐related materials and devices has basically been perfected in terms of quantum yield and external quantum efficiency (EQE). However, on the eve of its industrial application, some key technical indicators and technical processes need to be met and resolved. The development and transformation of QD materials and then focuses on the progress of luminescence linewidth and EQE of the PQD light‐emitting diode. Finally, several application avenues are reviewed for PQDs, and some challenges and opportunities in the field are proposed. [ABSTRACT FROM AUTHOR]

Mycobacterium bovis is the cause of bovine tuberculosis, and it can also cause disease in humans, with symptoms similar to those caused by M. tuberculosis. However, our understanding of its genomic diversity, biogeography, and drug resistance remains incomplete. We performed a comparative and phylogenetic analysis of 3228 M. bovis genomes from 24 countries. Following drug susceptibility testing, we applied a bacterial genome‐wide association study to capture associations between genomic variation and drug resistance in 74 newly isolated strains from China. The data show that the cattle‐adapted M. bovis were divided into six lineages with a strong phylogeographical population structure. Lineages 1 and 6 are the most widespread globally, while others show a strong geographical restriction. Note that 17.39% of M. bovis isolates were resistant to at least one drug in China. Furthermore, we identify genomic variations associated with an increased risk of resistance acquisition. This study furthers our knowledge of M. bovis diversity, biogeography, and drug resistance and will facilitate more deeply informed genomic tracking and surveillance to minimize its threat to human health, as a cause of zoonotic tuberculosis. [ABSTRACT FROM AUTHOR]

SUMMARY: Walnut (Juglans regia L.) anthracnose, induced by Colletotrichum gloeosporioides, is a catastrophic disease impacting the walnut industry in China. Although WRKY transcription factors play a key role in plant immunity, the function of the WRKY gene family in walnut resistance to C. gloeosporioides is not clear. Here, through transcriptome sequencing and quantitative real‐time polymerase chain reaction (qRT‐PCR), we identified a differentially expressed gene, JrWRKY21, that was significantly upregulated upon C. gloeosporioides infection in walnut. JrWRKY21 positively regulated walnut resistance to C. gloeosporioides, as demonstrated by virus‐induced gene silencing and transient gene overexpression. Additionally, JrWRKY21 directly interacted with the transcriptional activator of the pathogenesis‐related (PR) gene JrPTI5L in vitro and in vivo, and could bind to the W‐box in the JrPTI5L promoter for transcriptional activation. Moreover, JrPTI5L could induce the expression of the PR gene JrPR5L through binding to the GCCGAC motif in the promoter. Our data support that JrWRKY21 can indirectly activate the expression of the JrPR5L gene via the WRKY21–PTI5L protein complex to promote resistance against C. gloeosporioides in walnut. The results will enhance our understanding of the mechanism behind walnut disease resistance and facilitate the genetic improvement of walnut by molecular breeding for anthracnose‐resistant varieties. Significance Statement: Integrative transcriptomics and molecular biology approaches have revealed that JrWRKY21 not only interacts with JrPTI5L but also binds to the W‐box on its promoter to trigger its activity. JrWRKY21–JrPTI5L activates the expression of JrPR5L through JrPTI5L binding to the GCCGAC motif to promote resistance to C. gloeosporioides in walnut. [ABSTRACT FROM AUTHOR]

The long history of asexual reproduction of garlic using garlic cloves has resulted in virus accumulation and genetic depression. Propagation of garlic seedlings by tissue culture can both eliminate viruses and improve breeding efficiency. Aerial bulbs are the first-choice materials for breeding virus-free garlic seedlings under external conditions, but they show dormancy just like garlic bulbs. However, low temperatures can quickly break dormancy. In this research, we used a high-throughput sequencing method to sequence aerial bulbs during dormancy and after low-temperature-induced breaking of dormancy to screen out the key differentially expressed genes (DEGs) associated with low temperature and to provide a theoretical basis for exploring the molecular mechanism of low-temperature-induced breaking of aerial bulb dormancy. The high-throughput transcriptome sequencing results showed that 6,675 DEGs were upregulated and 36,596 DEGs were downregulated in the aerial bulbs given low-temperature treatment. Then, 19,507 DEGs were assigned KEGG annotations, among which most DEGs were annotated to the metabolism pathway (11,817 genes, accounting for 60.58%), followed by the genetic information processing pathway (4,521 genes, accounting for 23.18%). The DEGs were mostly concentrated in pathways such as protein processing in the endoplasmic reticulum, plant-pathogen interaction, plant hormone signal transduction, and ribosome biogenesis in eukaryotes, with significant enrichment. The key DEGs related to calcium signaling, hormonal signaling, and transcription factors were screened out, including CaM, CDPK, and CML in accessory pathways of calcium signaling; GA20ox, GAI1, and GA2ox in accessory pathways of hormonal signaling; and transcription factor genes such as MYB, AP2/ERF, bHLH, MADS, and bZIP. qRT-PCR verification results were consistent with the sequencing results, indicating that the transcriptome sequencing data were accurate and reliable. Our results provide a theoretical basis for breaking the dormancy of aerial bulbs with low-temperature treatment to produce virus-free seedlings and increase the output and quality of garlic. [ABSTRACT FROM AUTHOR]

Ultraviolet‐B (UV‐B) radiation and low temperature promote the accumulation of anthocyanins, which give apple skins their red colour. Although many transcription regulators have been characterized in the UV‐B and low‐temperature pathways, their interregulation and synergistic effects are not well understood. Here, a B‐box transcription factor gene, MdBBX20, was characterized in apple and identified to promote anthocyanin biosynthesis under UV‐B conditions in field experiments and when overexpressed in transgenic apple calli. The transcript level of MdBBX20 was significantly induced by UV‐B. Specific G‐box elements in the promoters of target genes were identified as interaction sites for MdBBX20. Further experimental interrogation of the UV‐B signalling pathways showed that MdBBX20 could interact with MdHY5 in vitro and in vivo and that this interaction was required to significantly enhance the promoter activity of MdMYB1. MdBBX20 also responded to low temperature (14°C) with the participation of MdbHLH3, which directly bound a low temperature‐response cis elements in the MdBBX20 promoter. These findings demonstrate the molecular mechanism by which MdBBX20 integrates low‐temperature‐ and UV‐B‐induced anthocyanin accumulation in apple skin. Ultraviolet‐B radiation (UV‐B) and low temperature (LT) promote anthocyanin accumulation and fruit colouration in apple skin. A B‐box transcription factor, MdBBX20, from "Fuji" apple integrates UV‐B‐induced and LT‐induced anthocyanin accumulation in apple skin. Highlights: These findings uncover unexpected functions for MdBBX20 in apple response to UV‐B and low temperature. To provide insights on how MdBBX20 mediates synergistic interactions between UV‐B and low‐temperature signalling pathways. [ABSTRACT FROM AUTHOR]

In many plants, anthocyanin biosynthesis is affected by environmental conditions. Ultraviolet-B (UV-B) radiation promotes anthocyanin accumulation and fruit coloration in apple skin, whereas high temperature suppresses these processes. In this study, we characterized a B-box transcription factor, MdCOL4, from 'Fuji' apple, and identified its role in anthocyanin biosynthesis by overexpressing its encoding gene in apple red callus. The expression of MdCOL4 was reduced by UV-B, but promoted by high temperature. We explored the regulatory relationship between heat shock transcription factors (HSFs) and MdCOL4, and found that MdHSF3b and MdHSF4a directly bound to the heat shock element cis- element of the MdCOL4 promoter. MdCOL4 interacted with MdHY5 to synergistically inhibit the expression of MdMYB1, and MdCOL4 directly bound to the promoters of MdANS and MdUFGT, which encode genes in the anthocyanin biosynthetic pathway, to suppress their expression. Our findings shed light on the molecular mechanism by which MdCOL4 suppresses anthocyanin accumulation in apple skin under UV-B and high temperature. [ABSTRACT FROM AUTHOR]

Bone chars pyrolyzed from bone residuals exhibit impressive performances to remove heavy metals given the integration of hydroxyapatite and carbon components. Considering the complexation of functional groups with metal ions and the adsorption of molecules by porous pores, this work prepared nitrogen-functionalized bone chars (NMBCs) with developed surface area (16.99- to 6.71-fold enhancement) and favorable surface modification (maximum 6.03 at% of N) via a ball milling of pristine bone chars with the assistance of ammonia hydroxide. NMBCs presented excellent maximum adsorption capacities for Cr(VI) (339.8 mg/g), U(VI) (466.5 mg/g), and methylene blue (338.3 mg/g) (pH 5.0, T 293 K) from ideal solutions. The effects of geochemical conditions including contact time, solution pH, ionic strength, humic acid, and ambient temperature on adsorption behaviors were investigated. NMBCs favorably adsorbed Cr(VI) (221.8 mg/g at pH 2.0, 175.4 mg/g at pH 4.0) and U(VI) (202.1 mg/g) from simulated wastewater and seawater respectively. With the analysis using spectroscopic technologies, the dominant mechanisms of Cr(VI), U(VI), and methylene blue were the integration of electrostatic attraction, surface complexation, precipitation, cation exchange, cation-π coordination and π–π interaction. This work provided a promising reference for the functionalization of bone chars with enhanced performance and multifunctionality in the remediation of pollutants. [Display omitted] • •Synthesis of nitrogen-functionalized bone chars by NH 3 ·H 2 O-assisted ball milling. • •16.99- to 6.71-fold enhancement of SA, maximum 6.03 at% of surface nitrogen. • •Efficiently capture of Cr(VI), U(VI), MB by NMBCs from ideal and simulated waters. • •Discussion of dominant sorption mechanisms with the spectroscopic analysis. [ABSTRACT FROM AUTHOR]

Metal halide perovskite nanocrystals (NCs) have been widely studied for application in photonics and optoelectronics due to their excellent photoelectric properties. Perovskite NCs with narrow luminescence linewidth and high photoluminescence quantum yield are excellent assembly modules for building large-scale NC superlattices. The coupling of optics and electricity in such excellent aggregates gives them exceptional collective photoelectric performance, such as superfluorescence, red-shifted emission, coupling-enhanced electron transport, etc. Perovskite NC superlattices are expected to become another hot research topic in optoelectronics. Here, we focus on the collective behavior of superlattices and review the recent progress of the self-assembly, collective photoelectric properties, and applications of perovskite NC superlattices. Finally, a few challenges and prospects are indicated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Improve the solubility of flunarizine hydrochloride by co-solvent. • The result of solubility data was correlated by Jouyban-Acree model and CNIBS/R-K model. • The co-solvency phenomenon was discussed. • Some of apparent thermodynamic properties were calculated. The solubility of flunarizine hydrochloride was improved by co-solvent in this work. In (acetonitrile + isopropanol) and (ethyl acetate + isopropanol) binary mixtures, it was measured at the temperature range from T = (273.15 To 313.15) K by the isothermal equilibrium method under 101.3 kPa. The solubility values in two mixtures increased firstly and then decreased with the increasing mass fraction of acetonitrile or ethyl acetate, and reached the maximum when the mass fraction of acetonitrile (w) = 0.60, and ethyl acetate (w) = 0.40 at all investigated temperatures. In pure solvents, the largest solubility is obtained in isopropanol, followed by acetonitrile and ethyl acetate. In mixture of (acetonitrile + isopropanol), the maximum and minimum values at 298.15 K are 5.98 × 10−3 and 2.91 × 10−3, respectively, and 5.91 × 10−3 and 2.24 × 10−3 in mixture of (ethyl acetate + isopropanol). The Jouyban-Acree model and CNIBS/R-K model were used to evaluate the results. Moreover, the relative contributions of solvent–solvent and solute–solvent interactions on the drug solubility variation were studied via the analysis of linear solvation energy relationships. The maximum value of relative average deviation (RAD) of Jouyban-Acree model was 4.20% in mixture of (acetonitrile + isopropanol), and for CNIBS/R-K model, it was 5.34% at 298.15 K in mixture of (acetonitrile + isopropanol). All values of apparent dissolution standard enthalpy (Δ H sol o), apparent molar standard Gibbs energy (Δ G sol o) and apparent dissolution standard entropy (Δ S sol o) are positive, which indicates the dissolution process is endothermic and entropy-increasing. The results of the relative contributions by enthalpy (ζ H) and by entropy (ζ TS) toward to Gibbs energy of the solution process show that the enthalpy is the main contributor to standard free energy of solution process. [ABSTRACT FROM AUTHOR]

Abstract: (+)-S-(1-propenyl)-l-cysteine S-oxide (1-PeCSO) is a key compound associated with Allium discoloration. The pathway by which 1-PeCSO participates in Allium discoloration in the presence of alliinase has been established, but whether 1-PeCSO results in the discoloration in the absence of this enzyme remains unknown. In the present study, one new model reaction system containing 1-PeCSO alone in a phosphate buffer was established to simulate discoloration of white onion tissue and garlic puree. Results showed that the model system generated yellowish-green colour at pH 3.0 and red colour at pH 5.0. Two red species were isolated and identified by high-resolution multistage MS analysis, molecular formulae of which are C24H30N2O5S (red species 1) and C27H36N2O6S2 (red species 2). Both of them are sulphur-containing pyrrole derivatives and have UV/visible maximum absorbances at 520 (species 1) and 523nm (species 2). The discoloration reactions occurring in this new system might represent a new pathway correlated with both onion reddening and garlic greening, emphasising that protein amino acids and alliinase are not necessary during the discoloration. [Copyright &y& Elsevier]

Abstract: An investigation into the phase stabilities of CaTiO3 under high pressure was conducted using first-principles calculations based on density functional theory. We have identified three candidate structures of CaTiO3, Pbnm, Pm3m and Cmcm, respectively. Our results demonstrate that a phase transition from orthorhombic (Pbnm) to cubic (Pm3m) is impossible for CaTiO3 under high pressure at ambient temperature, and further predict that Pbnm-CaTiO3 will transform to post-perovskite phase (Cmcm) at enough temperature and pressure. [Copyright &y& Elsevier]

Abstract: The texture and residual stress in FeMn/Ni80Fe20 multilayers were studied using conventional sin2 ψ method. The results show that the FeMn and Ni80Fe20 layers are both (111) textured. The sin2 ψ plots are nonlinear, which indicates a strong residual stress gradient through the depth of the sample. Fitting of the sin2 ψ plots give the residual stress in the samples. The in-plane residual stress is tensile and decreases from the surface of the sample to the substrate. The out-of-plane residual stress cannot be neglected because of the strong texture. In the two samples with the same total thickness but different periods, the FeMn layers have the same texture and residuals stress; while for Ni80Fe20 layer, as the thickness of each period increases, the texture becomes stronger and the residual stress becomes larger. It appears that the in-plane residual stress increases as the texture becomes stronger. [Copyright &y& Elsevier]

A novel insertion device is introduced, designated as the Mango wiggler, designed for synchrotron radiation (SR) imaging that provides a large field of view. This innovative device is constructed from two orthogonal planar wigglers with a small difference in their period lengths, eliciting the phase difference of the magnetic fields to incrementally transitions from 0 to π/2. Such a configuration enlarges the vertical divergence of the light source, as with the horizontal divergence. The appellation 'Mango wiggler' derives from the distinctive mango‐shaped contour of its radiation field. A comprehensive suite of theoretical analyses and simulations has been executed to elucidate the radiation properties of the Mango wiggler, employing SPECTRA and Mathematica as calculation tools. In conjunction with the ongoing construction of the High Energy Photon Source in Beijing a practical Mango wiggler device has been fabricated for utilization in SR imaging applications. Theoretical analyses were applied to this particular Mango wiggler to yield several theoretical conclusions, and several simulations were performed according to the measured magnetic field results. [ABSTRACT FROM AUTHOR]

Next‐generation light source facilities offer extreme spatial and temporal resolving power, enabling multiscale, ultra‐fast and dynamic characterizations. However, a trade‐off between acquisition efficiency and data quality needs to be made to fully unleash the resolving potential, for which purpose powerful denoising algorithms to improve the signal‐to‐noise ratio of the acquired X‐ray images are desirable. Yet, existing models based on machine learning mostly require massive and diverse labeled training data. Here we introduce a self‐supervised pre‐training algorithm with blind denoising capability by exploring the intrinsic physical symmetry of X‐ray patterns without requiring high signal‐to‐noise ratio reference data. The algorithm is more efficient and effective than algorithms without symmetry involved, including an supervised algorithm. It allows us to recover physical information from spatially and temporally resolved data acquired in X‐ray diffraction/scattering and pair distribution function experiments, where pattern symmetry is often well preserved. This study facilitates photon‐hungry experiments as well as in situ experiments with dynamic loading. [ABSTRACT FROM AUTHOR]

Background: Walnut anthracnose induced by Colletotrichum gloeosporioides is a disastrous disease affecting walnut production. The resistance of walnut fruit to C. gloeosporioides is a highly complicated and genetically programmed process. However, the underlying mechanisms have not yet been elucidated. Results: To understand the molecular mechanism underlying the defense of walnut to C. gloeosporioides, we used RNA sequencing and label-free quantitation technologies to generate transcriptomic and proteomic profiles of tissues at various lifestyle transitions of C. gloeosporioides, including 0 hpi, pathological tissues at 24 hpi, 48 hpi, and 72 hpi, and distal uninoculated tissues at 120 hpi, in anthracnose-resistant F26 fruit bracts and anthracnose-susceptible F423 fruit bracts, which were defined through scanning electron microscopy. A total of 21,798 differentially expressed genes (DEGs) and 1929 differentially expressed proteins (DEPs) were identified in F26 vs. F423 at five time points, and the numbers of DEGs and DEPs were significantly higher in the early infection stage. Using pairwise comparisons and weighted gene co-expression network analysis of the transcriptome, we identified two modules significantly related to disease resistance and nine hub genes in the transcription expression gene networks. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of the DEGs and DEPs revealed that many genes were mainly related to immune response, plant hormone signal transduction, and secondary metabolites, and many DEPs were involved in carbon metabolism and photosynthesis. Correlation analysis between the transcriptome data and proteome data also showed that the consistency of the differential expression of the mRNA and corresponding proteins was relatively higher in the early stage of infection. Conclusions: Collectively, these results help elucidate the molecular response of walnut fruit to C. gloeosporioides and provide a basis for the genetic improvement of walnut disease resistance. [ABSTRACT FROM AUTHOR]

Background: Light is the main source of energy and, as such, is one of the most important environmental factors for plant growth, morphogenesis, and other physiological responses. MicroRNAs (miRNAs) are endogenous non-coding RNAs that contain 21–24 nucleotides (nt) and play important roles in plant growth and development as well as stress responses. However, the role of miRNAs in the light response is less studied. We used tomato seedlings that were cultured in red light then transferred to blue light for 2 min to identify miRNAs related to light response by high-throughput sequencing. Results: A total of 108 known miRNAs and 141 predicted novel miRNAs were identified in leaf samples from tomato leaves treated with the different light qualities. Among them, 15 known and 5 predicted novel miRNAs were differentially expressed after blue light treatment compared with the control (red light treatment). KEGG enrichment analysis showed that significantly enriched pathways included zeatin biosynthesis (ko00908), homologous recombination (ko03440), and plant hormone signal transduction (ko04075). Zeatin biosynthesis and plant hormone signal transduction are related to plant hormones, indicating that plant hormones play important roles in the light response. Conclusion: Our results provide a theoretical basis for further understanding the role of miRNAs in the light response of plants. [ABSTRACT FROM AUTHOR]

Colloidal halide perovskite (CHP) quantum dots (QDs)/nanocrystals (NCs) have superior optoelectronic properties, such as high optical absorption coefficient, high photoluminescence quantum yield (PLQY), tunable bandgap, composition‐related luminescence, and low manufacturing cost, which have been considered as promising low‐dimensional semiconductor materials. Profiting from these unique characteristics, CHP NCs could be widely used in various optoelectronic devices, including light‐emitting diodes (LEDs), photodetectors (PDs), solar cells (SCs), and lasers. Synthesis is the basis for the wide use of CHP NCs, which plays a vital role in the research, development and application of CHPs. Therefore, we summarize the recent synthetic strategies, and their influencing factors (e. g. the effects of ligands, and anion exchange). Besides, a summary of their optoelectronic applications is plainly mentioned. Finally, we make a brief prospect and summarize the current problems and possible solutions of this area. [ABSTRACT FROM AUTHOR]

Recent technological breakthroughs in machine-learning-based AlphaFold2 (AF2) are pushing the prediction accuracy of protein structures to an unprecedented level that is on par with experimental structural quality. Despite its outstanding structural modeling capability, further experimental validations and performance assessments of AF2 predictions are still required, thus necessitating the development of integrative structural biology in synergy with both computational and experimental methods. Focusing on the B318L protein that plays an essential role in the African swine fever virus (ASFV) for viral replication, we experimentally demonstrate the high quality of the AF2 predicted model and its practical utility in crystal structural determination. Structural alignment implies that the AF2 model shares nearly the same atomic arrangement as the B318L crystal structure except for some flexible and disordered regions. More importantly, side-chain-based analysis at the individual residue level reveals that AF2′s performance is likely dependent on the specific amino acid type and that hydrophobic residues tend to be more accurately predicted by AF2 than hydrophilic residues. Quantitative per-residue RMSD comparisons and further molecular replacement trials suggest that AF2 has a large potential to outperform other computational modeling methods in terms of structural determination. Additionally, it is numerically confirmed that the AF2 model is accurate enough so that it may well potentially withstand experimental data quality to a large extent for structural determination. Finally, an overall structural analysis and molecular docking simulation of the B318L protein are performed. Taken together, our study not only provides new insights into AF2′s performance in predicting side-chain conformations but also sheds light upon the significance of AF2 in promoting crystal structural determination, especially when the experimental data quality of the protein crystal is poor. [ABSTRACT FROM AUTHOR]

Abstract As the necessary components for various modern electronic and optoelectronic devices, novel transparent electrodes (TEs) with the low cost, abundance features, and comparable performance of indium tin oxide (ITO) are inquired materials. Metal nanowires (NWs) with the excellent photoelectric properties as next-generation TE candidates have widely applications in smart optoelectronic devices such as electronic skins, wearable electronics, robotic skins, flexible and stretchable displays. This review describes the synthetic strategies for the preparation of metal NWs, the assemble process for metal NW films, and the practical aspects of metal NW films with the desired properties in various low-cost, flexible, and solution-based photoelectric devices. [ABSTRACT FROM AUTHOR]

In cyanobacteria and algae (but not plants), flavodoxin (Fld) replaces ferredoxin (Fd) under stress conditions to transfer electrons from photosystem I (PSI) to ferredoxin-NADP+ reductase (FNR) during photosynthesis. Fld constitutes a small electron carrier noncovalently bound to flavin mononucleotide (FMN), and also an ideal model for revealing the protein/flavin-binding mechanism because of its relative simplicity compared to other flavoproteins. Here, we report two crystal structures of apo-Fld from Synechococcus sp. PCC 7942, one dimeric structure of 2.09 Å and one monomeric structure of 1.84 Å resolution. Analytical ultracentrifugation showed that in solution, apo-Fld exists both as monomers and dimers. Our dimer structure contains two ligand-binding pockets separated by a distance of 45 Å, much longer than the previous structures of FMN-bound dimers. These results suggested a potential dimer-monomer transition mechanism of cyanobacterial apo-Fld. We further propose that the dimer represents the "standby" state to stabilize itself, while the monomer constitutes the "ready" state to bind FMN. Furthermore, we generated a new docking model of cyanobacterial Fld-FNR complex based on the recently reported cryo-EM structures, and mapped the special interactions between Fld and FNR in detail. • Cyanobacterial apo-Fld exists both as homodimer and monomer. • Two crystal structures of apo-Fld in homodimer and monomer were determined. • We propose a monomer-dimer transition mechanism of photosynthetic apo-Fld. • A new structural model of cyanobacterial Fld:FNR was built based on recent cryo-EM data. [ABSTRACT FROM AUTHOR]

The HEPS beamline software group is dedicated to the development, operation, and maintenance of unified experimental control and data acquisition software framework (Mamba, Figure 9) for high-throughput, multimodal, ultrafast, in-situ and dynamic experiments at HEPS. The High Energy Photon Source (HEPS) is a greenfield 4th-generation light source. HEPS Computing and Communication Group (HEPS-CC), provides the IT R&D and services for the facility and science communities, including IT infrastructure, network, computing, analysis software, data preservation and management, and public services. [Extracted from the article]

Background The woody halophyte Tamarix chinensis is a pioneer tree species in the coastal wetland ecosystem of northern China, exhibiting high resistance to salt stress. However, the genetic information underlying salt tolerance in T. chinensis remains to be seen. Here we present a genomic investigation of T. chinensis to elucidate the underlying mechanism of its high resistance to salinity. Results Using a combination of PacBio and high-throughput chromosome conformation capture data, a chromosome-level T. chinensis genome was assembled with a size of 1.32 Gb and scaffold N50 of 110.03 Mb. Genome evolution analyses revealed that T. chinensis significantly expanded families of HAT and LIMYB genes. Whole-genome and tandem duplications contributed to the expansion of genes associated with the salinity adaptation of T. chinensis. Transcriptome analyses were performed on root and shoot tissues during salt stress and recovery, and several hub genes responding to salt stress were identified. WRKY33 / 40, MPK3 / 4 , and XBAT31 were critical in responding to salt stress during early exposure, while WRKY40, ZAT10, AHK4, IRX9 , and CESA4 / 8 were involved in responding to salt stress during late stress and recovery. In addition, PER7/27/57/73 encoding class III peroxidase and MCM3/4/5/7 encoding DNA replication licensing factor maintained up/downregulation during salt stress and recovery stages. Conclusions The results presented here reveal the genetic mechanisms underlying salt adaptation in T. chinensis , thus providing important genomic resources for evolutionary studies on tamarisk and plant salt tolerance genetic improvement. [ABSTRACT FROM AUTHOR]

It has been established that kallikrein12 (KLK12) expression is closely related to bovine tuberculosis (bTB) development. Herein, we sought to clarify the regulatory mechanism of KLK12 and its application in tuberculosis diagnosis. KLK12 knockdown macrophages were produced by siRNA transfection. Bradykinin receptors (BR, including B1R and B2R) were blocked with specific inhibitors. Mannose-capped lipoarabinomannan (ManLAM) was extracted from Mycobacterium bovis (M. bovis) and used to study the mechanism of KLK12 activation. In addition, we constructed different mouse models representing the latent and active stages of M. bovis infection. Mouse models and clinical serum samples were used to assess the diagnostic value of biomarkers. Through the above methods, we confirmed that KLK12 regulates MMP-1 and MMP-9 via BR. KLK12 upregulation is mediated by the M. bovis-specific antigen ManLAM. KLK12, MMP-1, and MMP-9 harbor significant value as serological markers for differentiating between latent and active bTB, especially KLK12. In conclusion, we identified a novel signaling pathway, KLK12/BR/ERK/MMPs, in M. bovis-infected macrophages, which is activated by ManLAM. From this signaling pathway, KLK12 can be used as a serological marker to differentiate between latent and active bTB. Importantly, KLK12 also has enormous potential for the clinical diagnosis of human tuberculosis (TB). [ABSTRACT FROM AUTHOR]

The lysine (K) t RNA s ynthetase C -terminal (KTSC) domain containing proteins are widely spread in Bacteria, Archaea and Viruses, but the function of this short domain is unclear. The occurrence of the fusion of KTSC domain to a catalytic domain or domains related to DNA or RNA metabolisms suggests its potential role in DNA or RNA binding. Here, we report the characterization of Mvu8s from Methanolobus vulcani , which consists of a single KTSC domain. Mvu8s binds specifically to ssDNA with an affinity approximately 40- and 10-fold higher than those for dsDNA and ssRNA in vitro , respectively. It shows a slight preference to the G-rich DNA sequence but barely binds the A-stretch. Crystal structure of Mvu8s shows that it forms a homo-tetramer, with each monomer composed of a four-strand antiparallel β-sheet and a helix-turn-helix in the order of β1-β2-β3-α1-α2-β4. Four basic residues (R3, R7, K54 and K58) were found to serve important roles in ssDNA-binding. And, the spiral arrangement of the DNA interfaces in Mvu8s homo-tetramer presumably results in ssDNA wrapping. Our results not only offer clues of the functions of the KTSC domain containing proteins but also expand our knowledge on the non-oligonucleotide-binding (OB) fold single-stranded DNA-binding proteins in Archaea. [ABSTRACT FROM AUTHOR]

[Display omitted] • SeNPs and a subunit tuberculosis vaccine were synthesized. • SeNPs were firstly used as a mucosal adjuvant and exhibited a strong immunoenhancing effect. • SeNPs-AHB demonstrated a strong protective effect in mice infected with Mycobacterium bovis. • SeNPs can be used as an effective novel adjuvant for immunoenhancement. Selenium nanoparticles (SeNPs) enhance the immune response as adjuvants, increasing the efficacy of viral vaccines, including those for COVID-19. However, the efficiency of mucosal SeNPs in boosting vaccine-induced protective immunity against tuberculosis remains unclear. Therefore, this study aims to investigate whether the combination of SeNPs with the AH antigen (Ag85A-HspX) can boost respiratory mucosal immunity and thereby enhance the protective effects against tuberculosis. We synthesized SeNPs and assessed their impact on the immune response and protection against Mycobacterium bovis (M. bovis) as a mucosal adjuvant in mice, administered intranasally at a dose of 20 µg. SeNPs outperformed polyinosinic-polycytidylic acid (Poly IC) in stimulating the maturation of bone marrow-derived dendritic cells (BMDCs), which enhanced antigen presentation. SeNPs significantly activated and proliferated tissue-resident memory T cells (T RMs) and effector CD4+ T cells in the lungs. The vaccines elicited specific antibody responses in the respiratory tract and stimulated systemic Th1 and Th17 immune responses. Immunization with AH and SeNPs led to higher levels of mucosal secretory IgA in bronchoalveolar lavage fluid (BALF) and secretory IL-17 in splenocytes. Moreover, SeNPs immunized mice showed reduced M. bovis infection loads and inflammatory lesions in the lungs post-challenge. Notably, immunization with AH and SeNPs significantly reduced bacterial load in the lungs, achieving the lowest levels compared to all other tested groups. This study calls for pre-clinical investigation of AHB-SeNPs as an anti-bovine tuberculosis vaccine and for exploring its human vaccine potential, which is anticipated to aid in the development of innovative vaccines or adjuvants. [ABSTRACT FROM AUTHOR]

Inorganic perovskite quantum dots (QDs) have natural advantages in the field of light‐emitting diodes (LEDs) because of their high color purity and tunability in a wide range. However, when manufacturing efficiently mixed‐anion perovskite QDs (CsPbBrxI3−x) to meet the requirements of the pure red color standard in the display field (≈630 nm), results are difficult to control accurately due to the lack of exploration of its microscopic mechanism. Here, a microdynamics model is constructed for anion exchange dominated by vacancies which revealed the key role of polar solvent in reducing the surface energy barrier of anions through first‐principle calculations. Besides, a polar solvent construct in situ anion exchange channels method is proposed. Then, the precise control of anion exchange is demonstrated, and the precise regulation spectrum of the whole red‐light range (600–680 nm) is achieved. Finally, various QD LEDs (QLEDs) based on these tunable QDs are fabricated and exhibit excellent photoelectric performance in the main red range (620–680 nm). Among them, the champion QLEDs, have peak external quantum efficiency (EQE) of 16.3% at 633 nm and peak EQE of 18.2% at 646 nm, showing potential in meeting the requirements of display standard. [ABSTRACT FROM AUTHOR]

The bacterial type VI secretion system (T6SS) secretes many toxic effectors to gain advantage in inter‐bacterial competition and for eukaryotic host infection. The cognate immunity proteins of these effectors protect bacteria from the virulence of their own effectors. The T6SS injects its inner‐needle Hcp tube, the sharpening tip complex ‐consisting of VgrG and proline‐alanine‐alanine‐arginine repeats (PAAR) proteins‐ and toxic effectors into neighboring cells. Its functions are largely determined by the activities of its delivered effectors. Five PAAR proteins were found in the Pseudomonas aeruginosa PAO1 genome with three of them shown to facilitate the delivery of various effectors. Here, we report a putative virus‐type replication‐repair nuclease domain‐containing effector TseV encoded by the least investigated P. aeruginosa PAAR2 cluster. The crystal structure of its putative cognate effector TsiV is presented at 1.6 Å resolution. Through structure and sequence comparisons, we propose TseV‐TsiV to be a putative novel effector–immunity (E‐I) pair and we discuss the roles of other PAAR2 cluster encoded proteins. [ABSTRACT FROM AUTHOR]

The bacterial type VI secretion system (T6SS) is a powerful arsenal that fires many toxic effectors into neighboring cells to gain advantage over inter-bacterial competition and eukaryotic host infection. Meanwhile, the cognate immunity proteins of these effectors are employed to protect themselves from the virulence. TseT-TsiT is a newly discovered effector-immunity (E-I) protein pair secreted by T6SS of Pseudomonas aeruginosa. Our group had reported the crystal structure of TsiT before. Here, we report the crystal structure of P. aeruginosa TseT-TsiT complex at 3.1 Å resolution. The interface of TseT-TsiT is characterized in this work. Through structure and small angle X-ray scattering (SAXS) studies, we discover that the long C-terminal helix of TseT may be flexible. Combining the homolog comparison results, we propose that TseT may form an oligomer in favor of its putative nuclease activity. Although TsiT doesn't directly block the putative active-site of TseT, it may hinder the TseT's oligomerization process to neutralize its virulence. [ABSTRACT FROM AUTHOR]

Halide perovskites have been one of the most promising research hotspots in the optoelectronic field. Recently, the issue of ion migration has been proved to be of great significance to their long-term stability and performance of optoelectronic devices. However, the stability of perovskite Cs2SnX6 (X = I, Br, Cl) under the light or electric field conditions has not been explored. In this work, we reported halide ion migration in lead-free all‐inorganic perovskite Cs2SnX6. The calculated formation energy to some degree reveals the concentration of the halide vacancy, which provides the favorable conditions for halide ion migration. Importantly, the theoretical long-term ion migration barriers are investigated to be higher than 1.00 eV, indicating they are relatively stable compared to CsPbX3, and the computational result matches the experimental result with the Nernst−Einstein relation that we adopted. The halogen ion migration energy barrier is 0.91 eV under the bias of 5 V, indicating that the perovskite Cs2SnX6 is relatively stable under a certain electric field. Furthermore, the experimental comparison of XRD results demonstrate that perovskite Cs2SnX6 has no obvious ion migration under certain light conditions. Finally, the analysis results show the Sn–X bond strength that explains the cause of such high barriers. These results reveal the migration mechanism of halide ions and provide new impetus for their optoelectronic applications. [ABSTRACT FROM AUTHOR]

With the development of fourth‐generation synchrotron sources, coherent diffractive imaging (CDI) will be a mainstream method for 3D structure determination at nanometre resolution. The partial coherence of incident X‐rays plays a critical role in the reconstructed image quality. Here a wave optics model is proposed to analyze the effect of partial coherence on CDI for an actual beamline layout, based on the finite size of the source and the influence of the optics on the wavefront. Based on this model, the light field distribution at any plane, the coherence between any two points on this plane and CDI experiments can be simulated. The plane‐wave CDI simulation result also shows that in order to reconstruct good image quality of complex samples the visibility of the interference fringes of any two points in the horizontal and vertical directions of the incident light field at the sample needs to be higher than 0.95. [ABSTRACT FROM AUTHOR]

Quantum-dot-based light-emitting diode (QLED) with simultaneously improved efficiency and operational lifetime is achieved through charge balance engineering using a bilayered electron transport structure. The modulated device exhibits a color-saturated green emission, a low turn-on voltage of 2.0 V, a peak EQE of 21.63 per cent, and an operational lifetime of 1.15 h under an initial luminance of 4064 cd/m2, which is among the best-performing perovskite LEDs demonstrated so far. Perovskite quantum-dot-based light-emitting diodes (QLEDs) are highly promising for future solid-state lightings and high-definition displays due to their excellent color purity. However, their device performance is easily affected by charge accumulation induced luminescence quenching due to imbalanced charge injection in the devices. Here we report green perovskite QLEDs with simultaneously improved efficiency and operational lifetime through balancing the charge injection with the employment of a bilayered electron transport structure. The charge-balanced QLEDs exhibit a color-saturated green emission with a full-width at half-maximum (FWHM) of 18 nm and a peak at 520 nm, a low turn-on voltage of 2.0 V and a champion external quantum efficiency (EQE) of 21.63%, representing one of the most efficient perovskite QLEDs so far. In addition, the devices with modulated charge balance demonstrate a nearly 20-fold improvement in the operational lifetime compared to the control device. Our results demonstrate the great potential of further improving the device performance of perovskite QLEDs toward practical applications in lightings and displays via rational device engineering. [ABSTRACT FROM AUTHOR]

Background: Walnut anthracnose caused by Colletotrichum gloeosporioides (Penz.) Penz. and Sacc. is an important walnut production problem in China. Although the long non-coding RNAs (lncRNAs) are important for plant disease resistance, the molecular mechanisms underlying resistance to C. gloeosporioides in walnut remain poorly understood. Results: The anthracnose-resistant F26 fruits from the B26 clone and the anthracnose-susceptible F423 fruits from the 4–23 clone of walnut were used as the test materials. Specifically, we performed a comparative transcriptome analysis of F26 and F423 fruit bracts to identify differentially expressed LncRNAs (DELs) at five time-points (tissues at 0 hpi, pathological tissues at 24 hpi, 48 hpi, 72 hpi, and distal uninoculated tissues at 120 hpi). Compared with F423, a total of 14,525 DELs were identified, including 10,645 upregulated lncRNAs and 3846 downregulated lncRNAs in F26. The number of upregulated lncRNAs in F26 compared to in F423 was significantly higher at the early stages of C. gloeosporioides infection. A total of 5 modules related to disease resistance were screened by WGCNA and the target genes of lncRNAs were obtained. Bioinformatic analysis showed that the target genes of upregulated lncRNAs were enriched in immune-related processes during the infection of C. gloeosporioides, such as activation of innate immune response, defense response to bacterium, incompatible interaction and immune system process, and enriched in plant hormone signal transduction, phenylpropanoid biosynthesis and other pathways. And 124 known target genes for 96 hub lncRNAs were predicted, including 10 known resistance genes. The expression of 5 lncRNAs and 5 target genes was confirmed by qPCR, which was consistent with the RNA-seq data. Conclusions: The results of this study provide the basis for future functional characterizations of lncRNAs regarding the C. gloeosporioides resistance of walnut fruit bracts. [ABSTRACT FROM AUTHOR]

The genome of the thermophilic bacteriophage GVE2 encodes a putative t ail s pike p rotein (GVE2 TSP). Here we report the crystal structure of the truncated GVE2 TSP at 2.0-Å resolution lacking 204 amino acid residues at its N-terminus (ΔnGVE2 TSP), possessing a "vase" outline similar to other TSP's structures. However, ΔnGVE2 TSP displays structural characteristics distinct from other TSPs. Despite lacking 204 amino acid residues, the head domain forms an asymmetric trimer compared to symmetric in other TSPs, suggesting that its long N-terminus may be unique to the long-tailed bacteriophages. Furthermore, the α-helix of the neck is 5–7 amino acids longer than that of other TSPs. The most striking feature is that its binding domain consists of a β-helix with 10 turns, whereas other TSPs have 13 turns, even including the phage Sf6 TSP, which is the closest homologue of GVE2 TSP. The C-terminal structure is also quite different with those of other TSPs. Furthermore, we observed that ΔnGVE2 TSP can slow down growth of its host, demonstrating that this TSP is essential for the phage GVE2 to infect its host. Overall, the structural characteristics suggest that GVE2 TSP may be more primitive than other phage TSPs. [ABSTRACT FROM AUTHOR]

The bacterial type VI secretion system (T6SS) secretes many toxic effectors to gain advantage in interbacterial competition and for eukaryotic host infection. The cognate immunity proteins of these effectors protect bacteria from their own effectors. PldB is a T6SS trans‐kingdom effector in Pseudomonas aeruginosa that can infect both prokaryotic and eukaryotic cells. Three proteins, PA5086, PA5087 and PA5088, are employed to suppress the toxicity of PldB‐family proteins. The structures of PA5087 and PA5088 have previously been reported, but the identification of further distinctions between these immunity proteins is needed. Here, the crystal structure of PA5086 is reported at 1.90 Å resolution. A structural comparison of the three PldB immunity proteins showed vast divergences in their electrostatic potential surfaces. This interesting phenomenon provides an explanation of the stockpiling mechanism of T6SS immunity proteins. [ABSTRACT FROM AUTHOR]

Factor for inversion stimulation (Fis) is a versatile bacterial nucleoid‐associated protein that can directly bind and bend DNA to influence DNA topology. It also plays crucial roles in regulating bacterial virulence factors and in optimizing bacterial adaptation to various environments. Fis from Pseudomonas aeruginosa (PA4853, referred to as PaFis) has recently been found to be required for virulence by regulating the expression of type III secretion system (T3SS) genes. PaFis can specifically bind to the promoter region of exsA, which functions as a T3SS master regulator, to regulate its expression and plays an essential role in transcription elongation from exsB to exsA. Here, the crystal structure of PaFis, which is composed of a four‐helix bundle and forms a homodimer, is reported. PaFis shows remarkable structural similarities to the well studied Escherichia coli Fis (EcFis), including an N‐terminal flexible loop and a C‐terminal helix–turn–helix (HTH) motif. However, the critical residues for Hin‐catalyzed DNA inversion in the N‐terminal loop of EcFis are not conserved in PaFis and further studies are required to investigate its exact role. A gel‐electrophoresis mobility‐shift assay showed that PaFis can efficiently bind to the promoter region of exsA. Structure‐based mutagenesis revealed that several conserved basic residues in the HTH motif play essential roles in DNA binding. These structural and biochemical studies may help in understanding the role of PaFis in the regulation of T3SS expression and in virulence. [ABSTRACT FROM AUTHOR]

The type VI secretion system (T6SS) is a novel multiprotein needle‐like apparatus that is distributed widely in Gram‐negative bacteria. Bacteria harboring T6SSs inject various effectors into both eukaryotic and prokaryotic cells for interspecies competition or virulence‐related processes. The toxicities of the effectors can be neutralized by their cognate immunity proteins. Tde1 (Atu4350)–Tdi1 (Atu4351) has recently been characterized as a T6SS effector–immunity pair in the soil bacterium Agrobacterium tumefaciens and the neutralization mechanism remains unknown. Here, the crystal structure of the immunity protein Tdi1 was determined at 2.40 Å resolution by the single‐wavelength anomalous dispersion method. Structural analysis suggested that it is composed of a GAD‐like domain and an inserted DUF1851 domain, and both domains show low structural similarities to known structures. There is a positive groove mainly located in the GAD‐like domain that may be associated with nucleotide binding. The structure provides a basis for further study of the positive groove as a potential active site. The crystal structure of Tdi1 (Atu4351) from Agrobacterium tumefaciens is composed of a GAD‐like domain and an inserted DUF1851 domain. [ABSTRACT FROM AUTHOR]

Summary: Archaea have evolved various strategies in chromosomal organization. While histone homologues exist in most archaeal phyla, Cren7 is a chromatin protein conserved in the Crenarchaeota. Here, we show that Cren7 preferentially binds DNA with AT‐rich sequences over that with GC‐rich sequences with a binding size of 6~7 bp. Structural studies of Cren7 in complex with either an 18‐bp or a 20‐bp double‐stranded DNA fragment reveal that Cren7 binds to the minor groove of DNA as monomers in a head‐to‐tail manner. The neighboring Cren7 monomers are located on the opposite sides of the DNA duplex, with each introducing a single‐step sharp kink by intercalation of the hydrophobic side chain of Leu28, bending the DNA into an S‐shape conformation. A structural model for the chromatin fiber folded by Cren7 was established and verified by the analysis of cross‐linked Cren7‐DNA complexes by atomic force microscopy. Our results suggest that Cren7 differs significantly from Sul7, another chromatin protein conserved among Sulfolobus species, in both DNA binding and deformation. These data shed significant light on the strategy of chromosomal DNA organization in crenarchaea. Cren7 serves critical roles in chromosomal DNA organization in Crenarchaea. Structural studies reveal that Cren7 binds to the minor groove of DNA as monomers in a head‐to‐tail manner with a binding size of ~6 bp. The neighboring Cren7 monomers are located on the opposite sides of the DNA duplex, with each introducing a single‐step sharp kink by intercalation of the hydrophobic side chain of Leu28, bending the DNA into an S‐shape conformation. [ABSTRACT FROM AUTHOR]

Abstract The accurate modification of the tRNAIle anticodon wobble cytosine 34 is critical for AUA decoding in protein synthesis. Archaeal tRNAIle2 cytosine 34 is modified with agmatine in the presence of ATP by TiaS (tRNAIle2 agmatidine synthetase). However, no structure of apo-form full-length TiaS is available currently. Here, the crystal structures of apo TiaS and a complex of TiaS–agmatine–AMPPCP–Mg are presented, with properly folded zinc ribbon and Cys4-zinc coordination identified. Compared with tRNAIle2-bound form, the architecture of apo TiaS shows a totally different conformation of zinc ribbon. Molecular dynamics simulations of the docking complex between free-state TiaS and tRNAIle2 suggest that zinc ribbon domain is capable of performing large-scale motions to sample substrate binding-competent conformation. Principle component analysis and normal mode analysis show consistent results about the relative directionality of functionally correlated zinc ribbon motions. Apo TiaS and TiaS–agmatine–AMPPCP–Mg/TiaS–AMPCPP–Mg complex structures capture two snapshots of the flexible ATP-Mg binding p2loop step-by-step stabilization. Research from this study provides new insight into TiaS functional mechanism and the dynamic feature of zinc ribbons. Graphical Abstract Unlabelled Image Highlights • TiaS structure identified properly folded fourth domain as Cys4 zinc ribbon. • TiaS showed a totally different conformation from tRNAile2-bound state. • Computational structural analysis—molecular dynamic simulation and normal mode analysis—suggested functionally correlated direction preferences of zinc ribbon motions. • Alternative mechanism of catalysis by TiaS and implications for applied research were discussed. [ABSTRACT FROM AUTHOR]

HD-domain is a conserved domain, with the signature of histidine and aspartic (HD) residues doublets. HD-domain proteins may possess nucleotidase and phosphodiesterase activities, and they play important roles in signaling and nucleotide metabolism. In yeast, HD-domain proteins with nucleotidase activity remained unexplored. Here, we biochemically and structurally characterized two HD domain proteins YGK1 (YGL101W) and YB92 (YBR242W) from Saccharomyces cerevisiae as nucleoside 5ʹ-monophosphatases, with substrate preference for deoxyribonucleoside 5ʹ-monophosphatase over ribonucleoside 5ʹ-monophosphatase. By determining the crystal structure of YGK1, we unveiled that YGK1 structure resembled as the crystal structure of YfbR from E. coli . Size-exclusion chromatography and crosslinking studies suggested that YGK1 and YB92 existed in the form of a dimer, respectively, which were consistent with structural observation of YGK1. Site-directed mutagenesis demonstrated that more extensive conserved residues near the divalent metal coordinating active site were essential for YGK1 activity than previous suggested. The metal coordinating His89 and Asp90, and the neighboring conserved Glu93, Glu114 and Glu145 were individually critical for catalysis. In addition, alignments suggested that three flexible loops with hydrophobic residues might be implicated in substrate selectivity to nucleoside moiety. Together, our comparative structural and mutational studies suggested that YGK1 and YB92 functioned as 5ʹ-nucleotidases in S. cerevisiae . [ABSTRACT FROM AUTHOR]

Toxin-antitoxin (TA) systems are widespread in both bacteria and archaea, where they enable cells to adapt to environmental cues. TA systems play crucial roles in various cellular processes, such as programmed cell death, cell growth, persistence and virulence. Here, two distinct forms of the type II toxin-antitoxin complex HicAB were identified and characterized in Escherichia coli K-12, and both were successfully overexpressed and purified. The two proposed forms, HicABL and HicABS, differed in the presence or absence of a seven-amino-acid segment at the N-terminus in the antitoxin HicB. The short form HicABS readily crystallized under the conditions 0.1 M Tris-HCl pH 8.0, 20%( w/ v) PEG 6000, 0.2 M ammonium sulfate. The HicABS crystal diffracted and data were collected to 2.5 Å resolution. The crystal belonged to space group I222 or I212121, with unit-cell parameters a = 67.04, b = 66.31, c = 120.78 Å. Matthews coefficient calculation suggested the presence of two molecules each of HicA and HicBS in the asymmetric unit, with a solvent content of 55.28% and a Matthews coefficient ( VM) of 2.75 Å3 Da−1. [ABSTRACT FROM AUTHOR]

A method to calibrate and stabilize the incident X-ray energy for anomalous diffraction data collection is provided and has been successfully used at the single-crystal diffraction beamline 1W2B at the Beijing Synchrotron Radiation Facilities. Employing a feedback loop to control the movement of the double-crystal monochromator, this new method enables the incident X-ray energy to be kept within a 0.2 eV range at the inflection point of the absorption edge. [ABSTRACT FROM AUTHOR]

Light harvesting (LH) and carrier transport abilities of a photoactive layer, which are both crucial for optoelectronic devices such as solar cells and photodetectors (PDs), are typically hard to be synergistically improved. Taking perovskite as an example, a freeze-drying recrystallization method is used to construct porous films with improvements of both LH and carrier transport ability. During the freeze-drying casting process, the rapid solvent evaporation produces massive pores, the sizes of which can be adjusted to exploit the Mie scattering for enhancement of the LH ability. Meanwhile, owing to the strong iconicity, the interface between perovskite nanocrystals fused during recrystallization, which favors carrier transport. Subsequently, PDs based on these Mie porous and interface-fused films show a high on/off ratio of more than 104 and an external quantum efficiency value of 658 % under 9 V bias and 520 nm light irradiation. [ABSTRACT FROM AUTHOR]

Light harvesting (LH) and carrier transport abilities of a photoactive layer, which are both crucial for optoelectronic devices such as solar cells and photodetectors (PDs), are typically hard to be synergistically improved. Taking perovskite as an example, a freeze-drying recrystallization method is used to construct porous films with improvements of both LH and carrier transport ability. During the freeze-drying casting process, the rapid solvent evaporation produces massive pores, the sizes of which can be adjusted to exploit the Mie scattering for enhancement of the LH ability. Meanwhile, owing to the strong iconicity, the interface between perovskite nanocrystals fused during recrystallization, which favors carrier transport. Subsequently, PDs based on these Mie porous and interface-fused films show a high on/off ratio of more than 104 and an external quantum efficiency value of 658 % under 9 V bias and 520 nm light irradiation. [ABSTRACT FROM AUTHOR]

RsmI and RsmH are conserved S-Adenosylmethionine (AdoMet)-dependent methyltransferases (MTases) that are responsible for the 2′-O-methylation and N4-methylation of C1402 in bacterial 16S rRNA, respectively. Methylation of m4Cm1402 plays a role in fine-tuning the shape and functions of the P-site to increase the decoding fidelity, and was recently found to contribute to the virulence of Staphylococcus aureus in host animals. Here we report the 2.20-Å crystal structure of homodimeric RsmI from Escherichia coli in complex with the cofactor AdoMet. RsmI consists of an N-terminal putative RNA-binding domain (NTD) and a C-terminal catalytic domain (CTD) with a Rossmann-like fold, and belongs to the class III MTase family. AdoMet is specifically bound into a negatively charged deep pocket formed by both domains by making extensive contacts. Structure-based mutagenesis and isothermal titration calorimetry (ITC) assays revealed Asp100 and Ala124 are vital for AdoMet-binding. Although the overall fold of RsmI shows remarkable similarities to the characterized MTases involved in vitamin B12 biosynthesis, it exhibits a distinct charge distribution especially around the AdoMet-binding pocket because of different substrate specificity. The docking model of RsmI-AdoMet-RNA ternary complex suggested a possible base-flipping mechanism of the substrate RNA that has been observed in several known RNA MTases. Our structural and biochemical studies provide novel insights into the catalytic mechanism of C1402 methylation in 16S rRNA. [ABSTRACT FROM AUTHOR]

The toxin-antitoxin system is ubiquitously existed in bacteria and archaea, performing a wide variety of functions modulating cell fitness in response to environmental cues. In this report, we solved the crystal structure of the toxin-antitoxin HigBA complex from E. coli K-12 to 2.7 Å resolution. The crystal structure of the HigBA complex displays a hetero-tetramer (HigBA) 2 form comprised by two HigB and two HigA subunits. Each toxin HigB resumes a microbial RNase T1 fold, characteristic of a three antiparallel β-sheet core shielded by a few α-helices at either side. Each antitoxin HigA composed of all α-helices resembles a “C”-shaped clamp nicely encompassing a HigB in the (HigBA) 2 complex. Two HigA monomers dimerize at their N-terminal domain. We showed that HigA helix α1 was essential for HigA dimerization and the hetero-tetramer (HigBA) 2 formation, but not for a hetero-dimeric HigBA formation. HigA dimerization mediated by helix α1 was dispensable for DNA-binding, as a heterodimeric HigBA complex still bound to the higBA operator in vitro . The HigA C-terminal domain with a helix-turn-helix fold was essential for DNA binding. We also defined two palindromes in higBA operator specifically recognized by HigA and HigBA in vitro . [ABSTRACT FROM AUTHOR]

T:G base pair arising from spontaneous deamination of 5mC or polymerase errors is a great challenge for DNA repair of hyperthermophilic archaea, especially Crenarchaea. Most strains in this phylum lack the protein homologues responsible for the recognition of the mismatch in the DNA repair pathways. To investigate whether Cren7, a highly conserved chromatin protein in Crenarchaea, serves a role in the repair of T:G mispairs, the crystal structures of Cren7-GTAATTGC and Cren7-GTGATCGC complexes were solved at 2.0 Å and 2.1 Å. In our structures, binding of Cren7 to the AT-rich DNA duplex (GTAATTGC) induces opening of T2:G15 but not T10:G7 base pair. By contrast, both T:G mispairs in the GC-rich DNA duplex (GTGATCGC) retain the classic wobble type. Structural analysis also showed DNA helical changes of GTAATTGC, especially in the steps around the open T:G base pair, as compared to GTGATCGC or the matched DNAs. Surface plasmon resonance assays revealed a 4-fold lower binding affinity of Cren7 for GTAATTGC than that for GTGATCGC, which was dominantly contributed by the decrease of association rate. These results suggested that binding of Cren7 to DNA leads to T:G mispair opening in a sequence dependent manner, and therefore propose the potential roles of Cren7 in DNA repair. [ABSTRACT FROM AUTHOR]

Toxin–antitoxin (TA) loci are widespread in bacteria plasmids and chromosomes, and target various cellular functions to regulate cell growth and death. A type II TA system RnlA–RnlB from Escherichia coli is associated with phage-resistance. After the infection of bacteriophage T4 with Dmd defection, RnlA is activated by the disappearance of RnlB, resulting in the rapid degradation of T4 mRNAs. Dmd can bind to RnlA directly and neutralize RnlA toxicity to allow phage reproduction. Dmd represent a heterogenous antitoxin of RnlA replacing antitoxin RnlB. Here, we reported two structures of Dmd from T4 phage and RB69 phage. Both Dmd structures are high similar with a compacted domain composed of a four-stranded anti-parallel β-sheet and an α-helix. Chromatography and SAXS suggest Dmd forms a dimer in solution consistent with that in crystal. Structure-based mutagenesis of Dmd reveals key residues involved in RnlA-binding. Possibility cavities in Dmd used for compounds design were modeled. Our structural study revealed the recognition and inhibition mechanism of RnlA by Dmd and providing a potential laboratory phage prevention target for drug design. [ABSTRACT FROM AUTHOR]

Aims Baicalein is a widely used Chinese herbal medicine extracted from Labiatae plants Scutellaria baicalensis Georgi's dry root, which has multiple pharmacological activities. However, the precise mechanism of baicalein against myocardial remodeling remains poorly understood. The aim of our study was to investigate the underlying mechanism of baicalein treatment in rats model of heart failure (HF) and rat myocardial cells (H9C2). Main methods HF model was established by abdominal aorta constriction in rats and incubation with 50 μM isoproterenol for 48 h in H9C2 cells. Various molecular biological experiments were performed to assess the effects of baicalein on cardiac function, myocardial remodeling, apoptosis and Ca 2 + handling proteins. Key findings In the present study, first we found that baicalein alleviated HF in vivo. Additionally, treatment with baicalein inhibited the myocardial fibrosis, restrained the expression and activity of MMP2 and MMP9, and suppressed apoptosis in heart tissue. Moreover, baicalein could inhibit the cardiac myocyte hypertrophy and apoptosis induced by isoproterenol in vitro. Finally we found that baicalein could modulate the expressions and activities of Ca 2 + handling proteins, including downregulation of phosphorylation of Ca 2 + /calmodulin-dependent protein kinase II (CaMKII) and expression of Na(+)/Ca(2 +)-exchangers (NCX1), upregulation of sarcoplasmic reticulum Ca(2 +) ATPase 2 (SERCA2) and ryanodine receptor 2 (RYR2). Baicalein also restrained the decreased SERCA activity induced by aortic banding. Significance Our studies suggested that baicalein alleviated myocardial remodeling and improved cardiac function via modulation of Ca 2 + handling proteins, which may be a potential phytochemical flavonoid for therapeutics of HF. [ABSTRACT FROM AUTHOR]