28 research outputs found

    A conserved but plant-specific CDK-mediated regulation of DNA replication protein A2 in the precise control of stomatal terminal division

    Get PDF
    The R2R3-MYB transcription factor FOUR LIPS (FLP) controls the stomatal terminal division through transcriptional repression of the cell cycle genes CYCLIN-DEPENDENT KINASE (CDK) B1s (CDKB1s), CDKA; 1, and CYCLIN A2s (CYCA2s). We mutagenized the weak mutant allele flp-1 seeds with ethylmethane sulfonate and screened out a flp-1 suppressor 1 (fsp1) that suppressed the flp-1 stomatal cluster phenotype. FSP1 encodes RPA2a subunit of Replication Protein A (RPA) complexes that play important roles in DNA replication, recombination, and repair. Here, we show that FSP1/RPA2a functions together with CDKB1s and CYCA2s in restricting stomatal precursor proliferation, ensuring the stomatal terminal division and maintaining a normal guard-cell size and DNA content. Furthermore, we provide direct evidence for the existence of an evolutionarily conserved, but plant-specific, CDK-mediated RPA regulatory pathway. Serine-11 and Serine-21 at the N terminus of RPA2a are CDK phosphorylation target residues. The expression of the phosphorylation-mimic variant RPA2a(S11,21/D) partially complemented the defective cell division and DNA damage hypersensitivity in cdkb1;1 1;2 mutants. Thus, our study provides a mechanistic understanding of the CDK-mediated phosphorylation of RPA in the precise control of cell cycle and DNA repair in plants

    Field Orientation Dependent Magnetic Phases In Weyl Semimetal Co3Sn2S2

    Full text link
    Magnetism plays a key role in the emergence of topological phenomena in the Weyl semimetal Co3Sn2S2, which exhibits a ferromagnetic (FM) interactions along the c-axis of the crystal and an antiferromagnetic (AFM) interactions within the ab plane. Extensive studies on the temperature dependence of the magnetism with the magnetic field along the c-axis have uncovered a number of magnetic phases. Currently, the nature and origins of the reported magnetic phases are under debate. Here we report on magnetic field orientation effects on the magnetism in Co3Sn2S2. The shape of the hysteresis loop of the Hall resistance at a fixed temperature is found to change from rectangular to bow-tie-like as the magnetic field is tilted from the c-axis towards the ab plane, resembling that reported for magnetic fields along the c-axis as the temperature approaches the Curie temperature from below. Unlike their temperature-dependent counterparts, the newly observed bow-tie-like hysteresis loops show exchange bias. Our results showcase the contribution of the in-plane AFM interactions to the magnetism in Co3Sn2S2 and demonstrate a new way to tune its magnetic phases. They also shed light on the temperature-dependent magnetic phases occurring in the magnetic field along the c-axis of the crystal

    A new loss-of-function allele 28y reveals a role of ARGONAUTE1 in limiting asymmetric division of stomatal lineage ground cell

    No full text
    In Arabidopsis thaliana L., stomata are produced through a series of divisions including asymmetric and symmetric divisions. Asymmetric entry division of meristemoid mother cell produces two daughter cells, the smaller meristemoid and the larger sister cell, a stomatal lineage ground cell (SLGC). Stomatal lineage ground cells can differentiate into epidermal pavement cells but have the potential to divide asymmetrically, spacing divisions, to create satellite meristemoids. Peptide ligands and TOO MANY MOUTHS (TMM) and ERECTA family receptors regulate the initiation of stomatal lineages, activity, and orientation of spacing divisions. Here, we reported that a natural mutant 28y displayed an increased stomatal density and index. Using map-based cloning, we identified mutation in ARGONAUTE1 (AGO1) as the cause of 28y phenotypes. Time-lapse tracing of stomatal lineage cells reveals that stomatal overproduction in 28y is caused by the excessive asymmetric spacing division of SLGCs. Further genetic results demonstrated that AGO1 acts downstream of TMM and negatively regulates the SPCH transcripts, but in a brassinosteroid-independent manner. Upregulation of AGAMOUS-LIKE16 (AGL16) in 28y mutants suggests that AGO1 is required to restrict AGL16-mediated stomatal spacing divisions, an miRNA pathway in addition to ligand-receptor signaling modules

    Spatial Effects of Urban Agglomeration on Energy Efficiency: Evidence from China

    No full text
    The rapid expansion of large cities in China has substantially increased energy consumption. With ever stringent environmental policy in force, energy efficiency becomes an important issue. As the emergence of these urban agglomerations (UAs) is usually due to externality effects of spatially concentrated factors, this paper investigates how these factors can affect energy efficiency. Based on mono index, which is used to describe the spatial location information, we have constructed the spatial-structure index of UAs. Using panel data on ten major UAs in China from 2008 to 2017, we find that, in the whole sample, there is an inverse relationship between the spatial structure of UAs and energy efficiency: The higher the concentration degree of factors of UAs, the lower the energy efficiency. Across different regions, however, the relationship between spatial structure and energy efficiency is heterogeneous. The concentration degree of factors in the eastern and central regions of China is relatively high, and the spatial structure there does lead to a decrease in energy efficiency. By contrast, UAs in China’s western region are in a period of factor concentration, with spatial structure playing, in that region, a positive role in improving energy efficiency

    A2-type cyclin is required for the asymmetric entry division in rice stomatal development

    No full text
    In rice, and other major cereal grass crops, stomata are arranged in linear files parallel to the long growth axis of leaves. Each stomatal unit comprises two dumbbell-shaped guard cells flanked by two subsidiary cells. These morphological and developmental characteristics enable grass stomata to respond to environmental changes more efficiently. Cyclin-dependent kinases (CDKs) and their cyclin partners co-ordinate cell proliferation and differentiation during the development of multicellular organisms. In contrast to animals, plants have many more types and members of cyclins. In Arabidopsis, four A2-type cyclins (CYCA2s) function redundantly in regulating CDKB1 activity to promote the asymmetric division for stomatal initiation and the symmetric division of guard mother cells (GMCs). In this study, we examine the function of the single A2-type cyclin in rice, OsCYCA2; 1, as well the single B1-type CDK, OsCDKB1; 1. Cross-species complementation tests demonstrated that OsCYCA2; 1 and OsCDKB1; 1 could complement the defective stomatal phenotypes of Arabidopsis cyca2 and cdkb1 mutants, but also could suppress DNA endoduplication and cell enlargement. The early asymmetric divisions that establish the stomatal lineages are often missing within the stomatal cell files of OsCYCA2; 1-RNAi rice transgenic lines, leading to a significantly reduced stomatal production. However, GMC divisions are not disrupted either in OsCYCA2; 1-RNAi or in OsCDKB1; 1-RNAi rice transgenic lines as expected. Our results demonstrate a conserved but diverged function and behavior of rice A2-type cyclins, which might be associated with the distinct stomatal development pathways between rice and Arabidopsis

    Production characteristics and sweet-spots mapping of the Upper Devonian–Lower Mississippian Bakken Formation tight oil in southeastern Saskatchewan, Canada

    No full text
    A workflow that helps identify potential production sweet spots in the Middle Bakken tight oil play is proposed based on analysis of large amounts of production data. The proposed approach is a multivariate statistical model that extracts relevant information from a training dataset of production wells to facilitate geological similarity comparison between economic and sub-economic production wells. The model is applied to the Middle Bakken tight oil play in southeastern Saskatchewan. Data screening for diagnostic geological indicators for sweet spots reveals that several geological factors indicative for conventional oil reservoirs seem to work for the Middle Bakken tight oil play as well. These factors include: a) the NE Torqunay-Rocanville Trend serving as a preferred regional migration path for connecting mature source rock in southern Williston Basin and the Middle Bakken tight reservoir in southeastern Saskatchewan; b) the oils in the Bakken tight reservoirs along the U.S. and Canada border are more likely from local matured Bakken source rocks; c) subtle structural components enhancing the convergence of dispersed hydrocarbons over a large area; d) top seal and lateral barrier improving preservation, thus favouring oil productivity; e) orientation of maximum horizontal stress coincident with the direction of the variogram spatial continuity in ultimate recoverable reserves, so the direction of horizontal well has a significant impact on the oil productivity. Key words: tight oil reservoir, production characteristics, multivariate statistical model, production sweet-spot area, geological controls, Williston Basin, Bakken Formation shal

    Neck-chest-abdomen-pelvis Combined Enhanced CT in Breast Cancer Patients: Comparison between Dual-energy and Conventional Scanning Mode

    No full text
    Objective: To investigate the application value of dual-energy scanning scheme in neck-chest-abdomen-pelvis combined enhanced CT in patients with breast cancer patients by comparing with the conventional scanning scheme. Methods: A retrospective analysis was performed on 40 female patients with breast cancer who underwent neck-chest-abdomen-pelvis combined enhanced CT in Beijing hospital, including 20 patients scanned by conventional protocol and 20 patients scanned by dual-energy protocol. The radiation doses in arterial phase and delayed phase were compared between the two modes. The image qualities were evaluated by measuring signal-to-noise ratio (SNR), contrast noise ratio (CNR) and subjective scoring. Results: The radiation doses in arterial phase and delayed phase of conventional and dual-energy protocol were statistically different, and the radiation dose of dual-energy protocol was lower. There was no significant difference between the two modes in SNR and CNR of cervical arterial lymph nodes. There was significant difference between conventional and dual-energy mode in SNR and CNR value of axillary lymph nodes in thoracic artery phase. There was no significant difference in the subjective scores of conventional and dual-energy protocol of cervical lymph nodes. However, there was significant difference in the subjective scores of conventional and dual-energy protocol of axillary lymph nodes. The subjective score of dual-energy protocol was higher and the consistency of subjective score was better with Kappa value of 0.916. Conclusion: Compared with conventional scanning scheme, dual-energy scanning scheme for neck-chest-abdomen-pelvis combined enhanced CT shows lower radiation dose, simpler scanning process, higher patient cooperation degree, clearer display of axillary lymph nodes, which has important clinical application and promotion value

    A Novel Grid-Forming Strategy for Self-Synchronous PMSG under Nearly 100% Renewable Electricity

    No full text
    The demand for decarbonization calls for building up a nearly 100% renewable electricity resulting in Grid-forming (GFM) capability requirements. The foregoing paradigm shifts from synchronous AC systems to converter-based systems that need to remain stable and self-synchronous while providing GFM services. However, as this article’s analysis in the introduction, achieving such goals inevitably necessitates the implementation of a PLL controller and energy storage in a wind turbine, whereas it is not suitable to operate in a weak energy system. To tackle this issue, a novel grid-forming method is proposed. The suggested idea calls for creating a DC voltage controller in a grid-side converter that mimics inertia response and applying a Rotor kinetic energy storage (RKES) controller in a Generator-side converter. Moreover, a coordinated controller of RKES controllers and conventional low voltage ride-through (LVRT) is proposed to gain increases in dynamic performance and maintain grid-forming capabilities in the transient process. Extensive modeling, experimental results based on a semi-physical platform, and an actual wind farm demonstration project are provided to validate the proposed controls. The results demonstrate the effectiveness of the presented method when applied to the future 100% renewable electricity

    Table_1_Malnutrition diagnosed by the Global Leadership Initiative on Malnutrition criteria predicting survival and clinical outcomes of patients with cancer: A systematic review and meta-analysis.DOCX

    No full text
    ObjectivesRecently, some cohorts have looked into the use of Global Leadership Initiative on Malnutrition (GLIM) criteria in cancer patients. The objective of the current meta-analysis was to determine its utility in predicting clinical and survival outcomes for cancer patients.MethodSearching and screening literature from PubMed, Web of Science and Embase until September 13, 2022 was performed by two researchers independently. According to the exclusion and inclusion criteria, articles reporting the impact of malnutrition diagnosed by GLIM on long-term survival and clinical outcomes were included. Data of interest were also extracted from the included papers. The stability of the pooled results was evaluated using sensitivity analysis. With the aid of subgroup analysis, heterogeneity was revealed. To assess publication bias, Egger’s and Begg’s tests were conducted. The influence of publication bias on the pooling risk estimate was examined using a trim-and-fill analysis.Results15 studies that qualified for our study were identified. Pooled hazard ratio (HR) from both multivariate and univariate regression analysis showed a worse overall survival in GLIM-defined malnourished cancer patients than those in well-nourished status. Meanwhile, disease-free survival was also poorer in malnourished patients. Moreover, pooled odds ratio (OR) demonstrated that malnourished cancer patients were more likely to develop overall postoperative complications, complications ≥ Clavien-Dindo grade IIa and complications ≥ Clavien-Dindo grade IIIa. Two articles reported negative relation between GLIM-defined malnutrition and 30-day readmission/mortality.ConclusionGLIM-defined malnutrition possesses value in predicting poorer survival and clinical outcomes for cancer patients.Systematic review registration[https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=321094], identifier [CRD42022321094].</p
    corecore