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Stable matching of neurotransmitters with their receptors is fundamental to synapse function and reliable communication in neural circuits. Presynaptic neurotransmitters regulate the stabilization of postsynaptic transmitter receptors. Whether postsynaptic receptors regulate stabilization of presynaptic transmitters has received less attention. Here, we show that blockade of endogenous postsynaptic acetylcholine receptors (AChR) at the neuromuscular junction destabilizes the cholinergic phenotype in motor neurons and stabilizes an earlier, developmentally transient glutamatergic phenotype. Further, expression of exogenous postsynaptic gamma-aminobutyric acid type A receptors (GABAA receptors) in muscle cells stabilizes an earlier, developmentally transient GABAergic motor neuron phenotype. Both AChR and GABAA receptors are linked to presynaptic neurons through transsynaptic bridges. Knockdown of specific components of these transsynaptic bridges prevents stabilization of the cholinergic or GABAergic phenotypes. Bidirectional communication can enforce a match between transmitter and receptor and ensure the fidelity of synaptic transmission. Our findings suggest a potential role of dysfunctional transmitter receptors in neurological disorders that involve the loss of the presynaptic transmitter.
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Receptores Colinérgicos , Sinapses , Sinapses/metabolismo , Receptores Colinérgicos/metabolismo , Transmissão Sináptica/fisiologia , Neurônios Motores/metabolismo , Receptores de GABA-A/metabolismo , Ácido gama-Aminobutírico/metabolismo , Neurotransmissores/metabolismo , Colinérgicos , Receptores Pré-SinápticosRESUMO
The acyl-homoserine lactones (AHLs)-mediated LuxI/LuxR quorum sensing (QS) system orchestrates diverse bacterial behaviors in response to changes in population density. The role of the BjaI/BjaR1 QS system in Bradyrhizobium diazoefficiens USDA 110, which shares homology with LuxI/LuxR, remains elusive during symbiotic interaction with soybean. Here this genetic system in wild-type (WT) bacteria residing inside nodules exhibited significantly reduced activity compared to free-living cells, potentially attributed to soybean-mediated suppression. The deletion mutant strain ΔbjaR1 showed significantly enhanced nodulation induction and nitrogen fixation ability. Nevertheless, its ultimate symbiotic outcome (plant dry weight) in soybeans was compromised. Furthermore, comparative analysis of the transcriptome, proteome, and promoter activity revealed that the inactivation of BjaR1 systematically activated and inhibited genomic modules associated with nodulation and nitrogen metabolism. The former appeared to be linked to a significant decrease in the expression of NodD2, a key cell-density-dependent repressor of nodulation genes, while the latter conferred bacterial growth and nitrogen fixation insensitivity to environmental nitrogen. In addition, BjaR1 exerted a positive influence on the transcription of multiple genes involved in a so-called central intermediate metabolism within the nodule. In conclusion, our findings highlight the crucial role of the BjaI/BjaR1 QS circuit in positively regulating bacterial nitrogen metabolism and emphasize the significance of the soybean-mediated suppression of this genetic system for promoting efficient symbiotic nitrogen fixation by B. diazoefficiens.IMPORTANCEThe present study demonstrates, for the first time, that the BjaI/BjaR1 QS system of Bradyrhizobium diazoefficiens has a significant impact on its nodulation and nitrogen fixation capability in soybean by positively regulating NodD2 expression and bacterial nitrogen metabolism. Moreover, it provides novel insights into the importance of suppressing the activity of this QS circuit by the soybean host plant in establishing an efficient mutual relationship between the two symbiotic partners. This research expands our understanding of legumes' role in modulating symbiotic nitrogen fixation through rhizobial QS-mediated metabolic functioning, thereby deepening our comprehension of symbiotic coevolution theory. In addition, these findings may hold great promise for developing quorum quenching technology in agriculture.
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Bradyrhizobium , Glycine max , Percepção de Quorum/fisiologia , Fixação de Nitrogênio , Simbiose/fisiologia , Bradyrhizobium/genética , Bradyrhizobium/metabolismo , Transativadores/metabolismo , Nitrogênio/metabolismoRESUMO
A novel parallel beam combined lens (PBCL) was designed based on a parabolic monocapillary x-ray lens (PMXRL). The proposed PBCL converted a divergent X-ray beam into a near-solid parallel one, which retains the low divergence characteristics of PMXRL and significantly improves the intensity gain by about one order of magnitude. Compared with the traditional polycapillary parallel x-ray lens (PPXRL), the divergence performance of this lens is improved by an order of magnitude, and the light intensity gain is improved by 3-4 times. In addition, we developed a MATLAB-based visualization tool to simulate X-ray transmission within the PBCL through ray tracing. This tool facilitated the assessment of the PBCL's transmission efficiency and its comparison with conventional PMXRL and the PPXRL. The transport process of the PBCL is systematically investigated under the comprehensive consideration of multiple parameters. This study provided a new idea and theoretical basis for the further development of X-ray modulation technology.
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X ray ghost imaging (XGI) offers both radiation dose-reduction potential and cost-effective benefits owing to the utilization of a single-pixel detector. Most XGI schemes with laboratory x ray sources require a mechanically moving mask for either structured illumination or structured detection. In either configuration, however, its resolution remains limited by the source size and the unit size of the mask. Upon propagation, the details of the object can actually be magnified by the divergence of x rays, but at the same time, the penumbra effect produced by the finite source size is dramatically intensified, which ultimately leads to a degradation of image quality in XGI. To address these limitations, this work proposes a magnified XGI scheme using structured detection equipped with tapered polycapillary optics, which can efficiently suppress the object's penumbra as well as resolve the magnified details of the object. In general, the resolution of this scheme is no longer affected by the source size but by the microcapillary size of polycapillary. Our work fundamentally achieves cancellation of penumbra effect-induced aberration, thus paving the way for high-resolution magnified XGI.
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Hitherto, sulfur poisoning and hydrothermal aging have still been the challenges faced in practical applications of the Cu-SSZ-13 catalyst for the selective catalytic reduction (SCR) of NOx from diesel engine exhaust. Here, we elaborately design and conduct an in-depth investigation of the synthetic effects of hydrothermal aging and SO2 poisoning on pristine Cu-SSZ-13 and Cu-SSZ-13@Ce0.75Zr0.25O2 core@shell structure catalysts (Cu@CZ). It has been discovered that Cu@CZ susceptible to 750 °C with 5 vol % H2O followed by 200 ppm SO2 with 5 vol % H2O (Cu@CZ-A-S) could still maintain nearly 100% NOx conversion across the significantly wider temperature region of 200-425 °C, which is remarkably broader than that of the Cu-SSZ-13-A-S (300-400 °C) counterpart. The experimental results show that the hydrothermal aging process results in the migration of highly active Cu species within the cage of Cu-SSZ-13 to the CZ surface, forming CuO/CZ with abundant interfaces, which significantly enhances the adsorption and subsequent activation of NO, leading to the generation of reactive N2O3 and HONO intermediates. Moreover, density functional theory (DFT) calculations reveal that the H of the HONO* species can function as Brønsted acid sites, effectively adsorbing NH3 to generate the active NH4NO2* intermediate, which readily decomposes into N2 and H2O. Furthermore, this pathway is the rate-determining step with an energy barrier of 0.93 eV, notably lower than that of the "standard SCR" pathway (1.42 eV). Therefore, the formation of the new CuO/CZ interface profoundly boosts the low-temperature NH3-SCR activity and improves the coresistance of the Cu@CZ catalyst to sulfur poisoning and hydrothermal aging.
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The preparation of self-healing polyurethane elastomers (PUEs) incorporating dynamic bonds is of considerable practical significance. However, developing a PUE with outstanding mechanical properties and high self-healing efficiency poses a significant challenge. Herein, this work has successfully developed a series of self-healing PUEs with various outstanding properties through rational molecular design. These PUEs incorporate m-xylylene diisocyanate and reversible dimethylglyoxime as hard segment, along with polytetramethylene ether glycol as soft segment. A significant amount of dynamic oxime-carbamate and hydrogen bonds are formed in hard segment. The microphase separated structure of the PUEs enables them to be colorless with a transparency of >90%. Owing to the chemical composition and multiple dynamic interactions, the PUEs are endowed with ultra-high tensile strength of 34.5 MPa, satisfactory toughness of 53.9 MJ m-3, and great elastic recovery both at low and high strains. The movement of polymer molecular chains and the dynamic reversible interactions render a self-healing efficiency of 101% at 70 °C. In addition, this self-healing polyurethane could still maintain high mechanical properties after recycling. This study provides a design strategy for the preparation of a comprehensive polyurethane with superior overall performance, which holds wide application prospects in the fields of flexible displays and solar cells.
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Carbamatos , Elastômeros , Ligação de Hidrogênio , Oximas , Poliuretanos , Resistência à Tração , Poliuretanos/química , Oximas/química , Elastômeros/química , Carbamatos/química , Estrutura Molecular , ElasticidadeRESUMO
The mitochondrial (mt) genome can provide data for phylogenetic analyses and evolutionary biology. Herein, we sequenced and annotated the complete mt genome of Ergasilus anchoratus. This mt genome was 13852 bp long and comprised 13 protein-coding genes (PCGs), 22 tRNAs and 2 rRNAs. All PCGs used the standard ATN start codons and complete TAA/TAG termination codons. A majority of tRNA genes exhibited standard cloverleaf secondary structures, with the exception of one tRNA that lacked the TψC arm (trnC), and three tRNAs that lacked the DHU arm (trnR, trnS1 and trnS2). Phylogenetic analyses conducted using Bayesian inference (BI) and maximum likelihood (ML) methods both supported Ergasilidae as a monophyletic family forming a sister group to Lernaea cyprinacea and Paracyclopina nana. It also supported the monophyly of orders Calanoida, Cyclopoida, and Siphonostomatoida; and the monophyly of families Harpacticidae, Ergasilidae, Diaptomidae, and Calanidae. The gene orders of E. anchoratus and Sinergasilus undulatus were identical, which represents the first instance of two identical gene orders in copepods. More mt genomes are needed to better understand the phylogenetic relationships within Copepoda in the future.
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Copépodes , Genoma Mitocondrial , Filogenia , Animais , Genoma Mitocondrial/genética , Copépodes/genética , Copépodes/classificaçãoRESUMO
Oxygen vacancies (OV) in nonmetallic plasmonic photocatalysts can decrease the energy barrier for CO2 reduction, boosting C1 intermediate production for potential C2 formation. However, their susceptibility to oxidation weakens C1 intermediate adsorption. Herein we proposed a "photoelectron injection" strategy to safeguard OV in W18O49 by creating a W18O49/ZIS (W/Z) plasmonic photocatalyst. Moreover, photoelectrons contribute to the local multi-electron environment of W18O49, enhancing the intrinsic excitation of its hot electrons with extended lifetimes, as confirmed by in situ XPS and femtosecond transient absorption analysis. Density functional theory calculations revealed that W/Z with OV enhances CO2 adsorption, activating *CO production, while reducing the energy barrier for *COH production (0.054â eV) and subsequent *CO-*COH coupling (0.574â eV). Successive hydrogenation revealed that the free energy for *CH2CH2 hydrogenation (0.108â eV) was lower than that for *CH2CH2 desorption for C2H4 production (0.277â eV), favouring C2H6 production. Consequently, W/Z achieves an efficient C2H6 activity of 653.6â µmol g-1 h-1 under visible light, with an exceptionally high selectivity of 90.6 %. This work offers a new strategy for the rational design of plasmonic photocatalysts with high selectivity for C2+ products.
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The proposal of the "dual carbon" targets has provided direction for promoting China's economic green transformation and green innovation. As enterprises are important entities driving technological innovation in China, enhancing their green innovation capabilities holds significant practical significance for reducing carbon emissions. While the flourishing development of the digital economy currently provides new avenues and impetus for enterprise green innovation, research on the micro-level effects of green innovation driven by digital economy is still lacking. Therefore, based on data from Chinese cities spanning 2010 to 2021 and micro-level data of listed enterprises, this paper employs fixed effect model and intermediary effect model to empirically test the effect and mechanism of urban digital economy development on the quality and quantity of enterprise green innovation. Additionally, it investigates the carbon emission reduction effect resulting from digital economy development. The findings are as follows: (1) The development of digital economy exhibits a significant green innovation effect, effectively enhancing both the "quality and quantity" of enterprise green innovation. Particularly noteworthy is its impact on the quality of green innovation in enterprises, a result corroborated by several robustness tests. (2) Promoting regional knowledge spillover and alleviating enterprise financing constraints emerge as mechanisms through which the digital economy enhances the "quality and quantity" of enterprise green innovation. (3) Heterogeneity testing reveals that the digital economy exerts a greater green innovation effect on enterprises located in regions characterized by higher environmental regulations, high-tech industries, and state-owned enterprises. (4) Further analysis demonstrates that the digital economy effectively reduces enterprises carbon emissions and enhances their carbon performance by driving green innovation, thus providing endogenous impetus for achieving the "dual carbon" goals. By examining the effects and mechanisms of green innovation driven by digital economy from the perspectives of promoting knowledge spillover and alleviating financing constraints, this study enriches theoretical research on the relationship between the digital economy and green innovation at the enterprise micro-level. It offers new insights for governments in formulating green innovation policies and serves as a reference for green innovation decision-making in other developing countries.
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Carbono , China , Desenvolvimento Econômico , Invenções , CidadesRESUMO
Trait-based approaches are increasingly used to understand crop yield improvement, although they have not been widely applied to anatomical traits. Little is known about the relationships between root and leaf anatomy and yield in wheat. We selected 20 genotypes that have been widely planted in Luoyang, in the major wheat-producing area of China, to explore these relationships. A field study was performed to measure the yields and yield components of the genotypes. Root and leaf samples were collected at anthesis to measure the anatomical traits relevant to carbon allocation and water transport. Yield was negatively correlated with cross-sectional root cortex area, indicating that reduced root cortical tissue and therefore reduced carbon investment have contributed to yield improvement in this region. Yield was positively correlated with root xylem area, suggesting that a higher water transport capacity has also contributed to increased yields in this study. The area of the leaf veins did not significantly correlate with yield, showing that the high-yield genotypes did not have larger veins, but they may have had a conservative water use strategy, with tight regulation of water loss from the leaves. This study demonstrates that breeding for higher yields in this region has changed wheat's anatomical traits, reducing the roots' cortical tissue and increasing the roots' xylem investment.
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The demand for underwater pressure sensitive adhesives (PSAs) is rapidly increasing in fields such as underwater engineering and biomedicine. However, the achievement of underwater adhesion of PSAs remains a challenge because of the hydration layer that hinders the interaction between the adhesive and the substrate. Herein, a new type of underwater PSA was synthesized by the copolymerization of hydrophobic unsaturated poly(1,2-butylene oxide) (UPBO) and hydrophilic itaconic acid monomers using solvent-free ultraviolet curing. The PSA has demonstrated substrate-independent underwater adhesion strengths ranging from 108 to 141 kPa on both hydrophilic (glass, wood, steel) and hydrophobic (PET, PMMA, PTFE) substrates. The underwater adhesion performance of PSA remains stable during 30 adhesion-detachment cycles and incubation in water for 20 days. Notably, PSA shows cytocompatibility, antimicrobial, and degradable properties and can be used for rapid hemostasis of skin wounds. Experimental characterizations confirm that the process of underwater adhesion is achieved by hydrophobic alkyl side chains of the PBO chain segments, which repel water at the adhesive-substrate interface. This study should provide both practical and facile design strategies for multifunctional underwater PSAs that can be used in a variety of applications.
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Calcium sulfate and calcium sulfate-based biomaterials have been widely used in non-load-bearing bone defects for hundreds of years due to their superior biocompatibility, biodegradability, and non-toxicity. However, lower compressive strength and rapid degradation rate are the main limitations in clinical applications. Excessive absorption causes a sharp increase in sulfate ion and calcium ion concentrations around the bone defect site, resulting in delayed wound healing and hypercalcemia. In addition, the space between calcium sulfate and the host bone, resulting from excessively rapid absorption, has adverse effects on bone healing or fusion techniques. This issue has been recognized and addressed. The lack of sufficient mechanical strength makes it challenging to use calcium sulfate and calcium sulfate-based biomaterials in load-bearing areas. To overcome these defects, the introduction of various inorganic additives, such as calcium carbonate, calcium phosphate, and calcium silicate, into calcium sulfate is an effective measure. Inorganic materials with different physical and chemical properties can greatly improve the properties of calcium sulfate composites. For example, the hydrolysis products of calcium carbonate are alkaline substances that can buffer the acidic environment caused by the degradation of calcium sulfate; calcium phosphate has poor degradation, which can effectively avoid the excessive absorption of calcium sulfate; and calcium silicate can promote the compressive strength and stimulate new bone formation. The purpose of this review is to review the poor properties of calcium sulfate and its complications in clinical application and to explore the effect of various inorganic additives on the physicochemical properties and biological properties of calcium sulfate.
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Overgeneralization of fear to harmless situations is a core feature of anxiety disorders resulting from acute stress, yet the mechanisms by which fear becomes generalized are poorly understood. In this study, we show that generalized fear in mice results from a transmitter switch from glutamate to γ-aminobutyric acid (GABA) in serotonergic neurons of the lateral wings of the dorsal raphe. Similar change in transmitter identity was found in the postmortem brains of individuals with posttraumatic stress disorder (PTSD). Overriding the transmitter switch in mice prevented the acquisition of generalized fear. Corticosterone release and activation of glucocorticoid receptors mediated the switch, and prompt antidepressant treatment blocked the cotransmitter switch and generalized fear. Our results provide important insight into the mechanisms involved in fear generalization.
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Encéfalo , Medo , Generalização da Resposta , Ácido Glutâmico , Transtornos de Estresse Pós-Traumáticos , Estresse Psicológico , Ácido gama-Aminobutírico , Animais , Camundongos , Encéfalo/metabolismo , Medo/fisiologia , Ácido gama-Aminobutírico/metabolismo , Neurônios/metabolismo , Transtornos de Estresse Pós-Traumáticos/metabolismo , Estresse Psicológico/metabolismo , Ácido Glutâmico/metabolismo , Corticosterona/metabolismo , Receptores de Glucocorticoides/metabolismo , HumanosRESUMO
Coal gasification slag (CGS) contains variable amounts of heavy metals, which can negatively impact the environment. The mineral composition, element distribution, occurrence, and leaching characteristics of heavy metals in coal gasification coarse slag (CGCS) and coal gasification fine slag (CGFS) are studied to explain the leaching behavior of heavy metals in CGS. The movable components of heavy metals in CGFS (0.06 %-63.03 %) are significantly higher than those in CGCS (0 %-18.72 %). Leaching Environmental Assessment Framework 1313 data shows that heavy metals Zn, Cr, Cd, As, Pb, Ni, and Cu exhibit high leaching rates at low pH conditions, with Zn leaching concentrations as high as 2.11 mg/L at pH 2. Zn, Cr, and As exhibit obvious amphoteric leaching characteristics, and the leaching concentration of As at high pH (1.34 mg/L) even exceeds that at low pH (1.31 mg/L). Except for Cu, all heavy metals in CGS exceed the class III groundwater standard in some cases. Therefore, evaluation is needed before resource utilization of CGS due to potential leaching of some heavy metals.
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Cognitive deficits are a long-lasting consequence of drug use, yet the convergent mechanism by which classes of drugs with different pharmacological properties cause similar deficits is unclear. We find that both phencyclidine and methamphetamine, despite differing in their targets in the brain, cause the same glutamatergic neurons in the medial prefrontal cortex to gain a GABAergic phenotype and decrease their expression of the vesicular glutamate transporter. Suppressing the drug-induced gain of GABA with RNA-interference prevents the appearance of memory deficits. Stimulation of dopaminergic neurons in the ventral tegmental area is necessary and sufficient to produce this gain of GABA. Drug-induced prefrontal hyperactivity drives this change in transmitter identity. Returning prefrontal activity to baseline, chemogenetically or with clozapine, reverses the change in transmitter phenotype and rescues the associated memory deficits. The results reveal a shared and reversible mechanism that regulates the appearance of cognitive deficits upon exposure to different drugs.