Arabidopsis Sec14 proteins (SFH5 and SFH7) mediate interorganelle transport of phosphatidic acid and regulate chloroplast development.

Lipids establish the specialized thylakoid membrane of chloroplast in eukaryotic photosynthetic organisms, while the molecular basis of lipid transfer from other organelles to chloroplast remains further elucidation. Here we revealed the structural basis of Arabidopsis Sec14 homology proteins AtSFH5 and AtSFH7 in transferring phosphatidic acid (PA) from endoplasmic reticulum (ER) to chloroplast, and whose function in regulating the lipid composition of chloroplast and thylakoid development. AtSFH5 and AtSFH7 localize at both ER and chloroplast, whose deficiency resulted in an abnormal chloroplast structure and a decreased thickness of stacked thylakoid membranes. We demonstrated that AtSFH5, but not yeast and human Sec14 proteins, could specifically recognize and transfer PA in vitro. Crystal structures of the AtSFH5-Sec14 domain in complex with L-α-phosphatidic acid (L-α-PA) and 1,2-dipalmitoyl-sn-glycero-3-phosphate (DPPA) revealed that two PA ligands nestled in the central cavity with different configurations, elucidating the specific binding mode of PA to AtSFH5, different from the reported phosphatidylethanolamine (PE)/phosphatidylcholine (PC)/phosphatidylinositol (PI) binding modes. Quantitative lipidomic analysis of chloroplast lipids showed that PA and monogalactosyldiacylglycerol (MGDG), particularly the C18 fatty acids at sn-2 position in MGDG were significantly decreased, indicating a disrupted ER-to-plastid (chloroplast) lipid transfer, under deficiency of AtSFH5 and AtSFH7. Our studies identified the role and elucidated the structural basis of plant SFH proteins in transferring PA between organelles, and suggested a model for ER-chloroplast interorganelle phospholipid transport from inherent ER to chloroplast derived from endosymbiosis of a cyanobacteriumproviding a mechanism involved in the adaptive evolution of cellular plastids.

Cytidinediphosphate diacylglycerol synthase-Mediated phosphatidic acid metabolism is crucial for early embryonic development of Arabidopsis.

Embryonic development is a key developmental event in plant sexual reproduction; however, regulatory networks of plant early embryonic development, particularly the effects and functional mechanisms of phospholipid molecules are still unknown due to the limitation of sample collection and analysis. We innovatively applied the microspore-derived in vitro embryogenesis of Brassica napus and revealed the dynamics of phospholipid molecules, especially phosphatidic acid (PA, an important second messenger that plays an important role in plant growth, development, and stress responses), at different embryonic developmental stages by using a lipidomics approach. Further analysis of Arabidopsis mutants deficiency of CDS1 and CDS2 (cytidinediphosphate diacylglycerol synthase, key protein in PA metabolism) revealed the delayed embryonic development from the proembryo stage, indicating the crucial effect of CDS and PA metabolism in early embryonic development. Decreased auxin level and disturbed polar localization of auxin efflux carrier PIN1 implicate that CDS-mediated PA metabolism may regulate early embryogenesis through modulating auxin transport and distribution. These results demonstrate the dynamics and importance of phospholipid molecules during embryo development, and provide informative clues to elucidate the regulatory network of embryogenesis.

Constructing Novel High Dielectric Constant Polyimides Containing Dipolar Pendant Groups with Enhanced Orientational Polarization.

Polymer dielectrics with high dielectric constant are urgently demanded for potential electrical and pulsed power applications. The design of polymers with side chains containing dipolar groups is considered an effective method for preparing materials with a high dielectric constant and low loss. This study synthesizes and comprehensively compare the dielectric properties of novel polyimides with side chains containing urea (BU-PI), carbamate (BC-PI), and sulfonyl (BS-PI) functional groups. The novel polyimides exhibit relatively high dielectric constant and low dielectric loss values due to the enhanced orientational polarization and suppressed dipole-dipole interactions of dipolar groups. In particular, BU-PI containing urea pendant groups presents the highest dielectric constant of 6.14 and reasonably low dielectric loss value of 0.0097. The strong γ transitions with low activation energies derived from dielectric spectroscopy measurements have been further evaluated to demonstrate the enhanced free rotational motion of urea pendant dipoles. In energy storage applications, BU-PI achieves a discharged energy density of 6.92 J cm-3 and a charge-discharge efficiency above 83% at 500 MV m-1. This study demonstrates that urea group, as dipolar pendant group, can provide polymers with better dielectric properties than the most commonly used sulfonyl groups.

Sulfonated Polyimide Membranes Constructed by Main-Chain and Molecular-Network Engineering Strategy for Direct Methanol Fuel Cell.

Excessive swelling is one important factor that leads to high fuel permeability and limited operating concentration of methanol for proton exchange membranes. Herein, a collaborative strategy of main-chain and molecular-network engineering is applied to lower swelling ratio and improve methanol resistance for highly sulfonated polyimide. Two m-phenylenediamine monomers (4-(2,3,5,6-tetrafluoro-4-vinylphenoxy)benzene-1,3-diamine and 4,6-bis(2,3,5,6-tetrafluoro-4-vinylphenoxy)benzene-1,3-diamine) with tetrafluorostyrol groups are designed and synthesized. Two series of cross-linked sulfonated polyimides (CSPI-Ts, CSPI-Bs) are prepared from the two diamines, 4,4'-diaminostilbene-2,2'-disulfonic acid and 1,4,5,8-naphthalenetetracarboxylicdianhydride. The rigid main-chain structure is cornerstone for wet CSPI-Ts and CSPI-Bs remaining stable at elevated temperatures. The introduction of hydrophobic cross-linked network further improves their dimensional stability and methanol resistance. CSPI-Ts and CSPI-Bs show obviously improved performances containing high proton conductivity (121 ± 0.27-158 ± 0.35 S cm-1 ), low swelling ratio (9.6 ± 0.40%-16.1 ± 0.01%) and methanol permeability (4.14-7.69 × 10-7 cm2 s-1 ) at 80 °C. The direct methanol fuel cell (DMFC) is assembled from CSPI-T-10 with balanced properties, and it exhibits high maximum power density (PDmax ) of 82.3 and 72.6 mW cm-2 in 2 and 10 m methanol solution, respectively. The ratio of PDmax in 10 m methanol solution to the value in 2 m methanol solution is as high as 88%. The CSPI-T-10 is promising proton exchange membrane candidate for DMFC application.

Side-Chain-Type High Dielectric-Constant Dipolar Polyimides with Temperature Resistance.

Innovative dielectric materials with high-temperature resistance and outstanding dielectric properties have attracted tremendous attention in advanced electronical fields. Polyimide(PI) is considered a promising candidate for the modern electronic industry due to its excellent dielectric properties and comprehensive properties. However, the limited-adjustable range of dielectric constant and the difficulty to obtain a high dielectric constant restrict the application of PI as high dielectric materials. Herein, a novel diamine monomer (2,2'-bis((methylsulfonyl)methyl)-[1,1'-biphenyl]-4,4'-diamine (BSBPA)) containing a rigid biphenyl structure and high dipolar sulfonyl pendant groups is designed for high dielectric polyimides. The rigid biphenyl and polar sulfonyl pendant groups can reasonably optimize the molecular structure and orientational polarization of polyimides to improve their dielectric properties and thermal properties. Moreover, the effect of different bridge linkages on the dielectric properties is studied by using the different dianhydrides. Thus, the PI-BSBPA films especially the DSDA-BSBPA film (DSDA: 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride) achieve great thermal properties (T5%d of 377 °C and Tg of 358 °C) and excellent dielectric properties (6.95 at 1 kHz) along with high discharged energy density of 5.25 J cm-3 and charge-discharge efficiency of 90%. The collaborative control of main-chain and side-chain engineering is effective to endow the polyimides with high-temperature tolerance and high dielectric performance.

Performance evaluation of a deep learning-based cascaded HRNet model for automatic measurement of X-ray imaging parameters of lumbar sagittal curvature.

PURPOSE: To develop a deep learning-based cascaded HRNet model, in order to automatically measure X-ray imaging parameters of lumbar sagittal curvature and to evaluate its prediction performance. METHODS: A total of 3730 lumbar lateral digital radiography (DR) images were collected from picture archiving and communication system (PACS). Among them, 3150 images were randomly selected as the training dataset and validation dataset, and 580 images as the test dataset. The landmarks of the lumbar curve index (LCI), lumbar lordosis angle (LLA), sacral slope (SS), lumbar lordosis index (LLI), and the posterior edge tangent angle of the vertebral body (PTA) were identified and marked. The measured results of landmarks on the test dataset were compared with the mean values of manual measurement as the reference standard. Percentage of correct key-points (PCK), intra-class correlation coefficient (ICC), Pearson correlation coefficient (r), mean absolute error (MAE), mean square error (MSE), root-mean-square error (RMSE), and Bland-Altman plot were used to evaluate the performance of the cascade HRNet model. RESULTS: The PCK of the cascaded HRNet model was 97.9-100% in the 3 mm distance threshold. The mean differences between the reference standard and the predicted values for LCI, LLA, SS, LLI, and PTA were 0.43 mm, 0.99°, 1.11°, 0.01 mm, and 0.23°, respectively. There were strong correlation and consistency of the five parameters between the cascaded HRNet model and manual measurements (ICC = 0.989-0.999, R = 0.991-0.999, MAE = 0.63-1.65, MSE = 0.61-4.06, RMSE = 0.78-2.01). CONCLUSION: The cascaded HRNet model based on deep learning algorithm could accurately identify the sagittal curvature-related landmarks on lateral lumbar DR images and automatically measure the relevant parameters, which is of great significance in clinical application.

The Deep Vascular Plexus Density Is Closely Related to Myopic Severity.

OBJECTIVES: The aim of the study was to investigate the relationship between myopic severity and the retinal microvasculature based on quantitative variables using optical coherence tomography angiography (OCTA) and to identify OCTA indicators of microvascular network loss in myopia. METHODS: This cross-sectional study included 123 eyes of 123 myopic subjects. The included eyes were divided into three groups according to the spherical equivalent (SE) and axial length (AL): low myopia (LM) (-3.00 D ≤ SE ≤ -0.50 D), moderate myopia (MM) (-6.00 D ≤ SE < -3.00 D), and high myopia (HM) (-9.00 D ≤ SE < -6.00 D or AL >26 mm). All the eyes underwent OCTA scans. The densities and thicknesses of the macular and peripapillary zones, including the foveal avascular zone (FAZ) area, superficial vascular plexus (SVP) density, deep vascular plexus (DVP) density, ganglion cell complex (GCC) thickness, full retinal thickness, radial peripapillary capillary plexus (RPCP) density, and retinal nerve fiber layer (RNFL) thickness, were automatically exported. RESULTS: Compared to the LM or MM group, the HM group had a significantly reduced FAZ area (p < 0.05). In most sectors of the parafoveal and perifoveal areas, the HM group had significantly lower DVP density and higher retinal thickness than the LM and MM groups (all p < 0.05). However, significant differences among the three groups in only one or several sectors were observed with regard to SVP density, GCC thickness, and RNFL thickness, and no significant differences among the three groups in any sector were noticed in RPCP density. Perifoveal DVP density and perifoveal full retinal thickness were positively associated with SE and negatively associated with AL in stepwise multiple linear regression analyses adjusted for sex and age. CONCLUSION: DVP density was closely related to myopic severity. Reduced perifoveal DVP density may serve as an indicator of microvascular network loss in myopia. OCTA may provide useful and crucial information for monitoring the progression of myopia.

Pyrophosphate-fructose 6-phosphate 1-phosphotransferase (PFP1) regulates starch biosynthesis and seed development via heterotetramer formation in rice (Oryza sativa L.).

Pyrophosphate-fructose 6-phosphate 1-phosphotransferase (PFP1) reversibly converts fructose 6-phosphate and pyrophosphate to fructose 1, 6-bisphosphate and orthophosphate during glycolysis, and has diverse functions in plants. However, mechanisms underlying the regulation of starch metabolism by PFP1 remain elusive. This study addressed the function of PFP1 in rice floury endosperm and defective grain filling. Compared with the wild type, pfp1-3 exhibited remarkably low grain weight and starch content, significantly increased protein and lipid content, and altered starch physicochemical properties and changes in embryo development. Map-based cloning revealed that pfp1-3 is a novel allele and encodes the regulatory ß-subunit of PFP1 (PFP1ß). Measurement of nicotinamide adenine dinucleotide (NAD+) showed that mutation of PFP1ß markedly decreased its enzyme activity. PFP1ß and three of four putative catalytic α-subunits of PFP1, PFP1α1, PFP1α2, and PFP1α4, interacted with each other to form a heterotetramer. Additionally, PFP1ß, PFP1α1 and PFP1α2 also formed homodimers. Furthermore, transcriptome analysis revealed that mutation of PFP1ß significantly altered expression of many essential enzymes in starch biosynthesis pathways. Concentrations of multiple lipid and glycolytic intermediates and trehalose metabolites were elevated in pfp1-3 endosperm, indicating that PFP1 modulates endosperm metabolism, potentially through reversible adjustments to metabolic fluxes. Taken together, these findings provide new insights into seed endosperm development and starch biosynthesis and will help in the breeding of rice cultivars with higher grain yield and quality.

Phospholipase D-derived phosphatidic acid promotes root hair development under phosphorus deficiency by suppressing vacuolar degradation of PIN-FORMED2.

Root hair development is crucial for phosphate absorption, but how phosphorus deficiency affects root hair initiation and elongation remains unclear. We demonstrated the roles of auxin efflux carrier PIN-FORMED2 (PIN2) and phospholipase D (PLD)-derived phosphatidic acid (PA), a key signaling molecule, in promoting root hair development in Arabidopsis thaliana under a low phosphate (LP) condition. Root hair elongation under LP conditions was greatly suppressed in pin2 mutant or under treatment with a PLDζ2-specific inhibitor, revealing that PIN2 and polar auxin transport and PLDζ2-PA are crucial in LP responses. PIN2 was accumulated and degraded in the vacuole under a normal phosphate (NP) condition, whereas its vacuolar accumulation was suppressed under the LP or NP plus PA conditions. Vacuolar accumulation of PIN2 was increased in pldζ2 mutants under LP conditions. Increased or decreased PIN2 vacuolar accumulation is not observed in sorting nexin1 (snx1) mutant, indicating that vacuolar accumulation of PIN2 is mediated by SNX1 and the relevant trafficking process. PA binds to SNX1 and promotes its accumulation at the plasma membrane, especially under LP conditions, and hence promotes root hair development by suppressing the vacuolar degradation of PIN2. We uncovered a link between PLD-derived PA and SNX1-dependent vacuolar degradation of PIN2 in regulating root hair development under phosphorus deficiency.

Na3V2(PO4)3/Porous Carbon Skeleton Embellished with ZIF-67 for Sodium-Ion Storage.

Sodium super ionic conductor (NASICON) Na3V2(PO4)3 (NVP) is a type of promising cathode material for sodium-ion batteries (SIBs) with superior structural integrity, high energy density, and fast diffusion of sodium ions. However, NVP suffers from intrinsically low electrical conductivity, which results in poor rate performance. Herein, we report on the outstanding cathode performance of Na3V2(PO4)3 (NVP@C-ZIF67) wrapped by the ZIF-67-derived carbon, which was prepared by sol-gel method and solid-phase method. Electrochemical measurements show an initial discharge-specific capacity of 135 mA h g-1 at 1 C, and the discharge capacity maintains 82 mA h g-1 after 1000 cycles at 10 C. The results indicate the improvement in electrical conductivity and electrochemical performance due to the Co doping from ZIF-67. Moreover, we calculate the diffusion coefficient of sodium ions by the cyclic voltammetry (CV, DNa+ = 1.521 × 10-11 and 2.3484 × 10-11 cm2 s-1 for charging and discharging, respectively) and the galvanostatic intermittent titration technique (GITT, DNa+ ranges from 10-11-10-15 cm2 s-1). The exceptional performance is ascribed to the excellent structural stability and outstanding electrical conductivity of NVP modified by porous carbon skeleton and ZIF-67-derived carbon.

Polycyclic aromatic hydrocarbons exposure and hematotoxicity in occupational population: A two-year follow-up study.

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental and occupational pollutants. To date, the effect and mechanism by which PAHs exposure impaired hematopoietic system remains unclear. METHODS: We examined the capability of PAHs to disrupt hematopoiesis in a study of 639 male participants in China by measuring complete blood counts (CBC) in 2013 and 2014. Gas chromatography-mass spectrometry (GC/MS) method was used to measure airborne levels of PAHs and benzene. We measured 1-hydroxypyrene (1-OHP), S-phenylmercapturic acid (SPMA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urinary by ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method. RESULTS: We found decreased dose-response of white blood cells, eosinophils, monocytes and lymphocytes with increased PAHs exposure in two consecutive years. We did not find association between benzene with CBC in our study. After stratification analysis by smoking status, the findings were highly consistent. White blood cells, monocytes and red blood cell counts were decreased in high urinary 8-OHdG group. CONCLUSIONS: Our study showed that PAHs could impair the hematopoietic system independently, and oxidative stress might play an important role in potential hematotoxicity.

Glaciation-based isolation contributed to speciation in a Palearctic alpine biodiversity hotspot: Evidence from endemic species.

Organisms are unevenly distributed on earth and the evolutionary drivers of that have puzzled ecologists and evolutionary biologists for over a century. Even though many studies have focused on the mechanisms of unevenly distributed fauna and flora, there remains much to learn about the evolutionary drivers behind biodiversity hotspots. In the Tibetan Plateau and Hengduan Mountains, a biodiversity hotspot in the Palearctic realm, alpine uplift cannot be the driver for recent speciation (

Recent Development of Thermoelectric Polymers and Composites.

Thermoelectric materials can be used as the active materials in thermoelectric generators and as Peltier coolers for direct energy conversion between heat and electricity. Apart from inorganic thermoelectric materials, thermoelectric polymers have been receiving great attention due to their unique advantages including low cost, high mechanical flexibility, light weight, low or no toxicity, and intrinsically low thermal conductivity. The power factor of thermoelectric polymers has been continuously rising, and the highest ZT value is more than 0.25 at room temperature. The power factor can be further improved by forming composites with nanomaterials. This article provides a review of recent developments on thermoelectric polymers and polymer composites. It focuses on the relationship between thermoelectric properties and the materials structure, including chemical structure, microstructure, dopants, and doping levels. Their thermoelectric properties can be further improved to be comparable to inorganic counterparts in the near future.

Phosphatidic acid plays key roles regulating plant development and stress responses.

Phospholipids, including phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS) and phosphoinositides, have emerged as an important class of cellular messenger molecules in various cellular and physiological processes, of which PA attracts much attention of researchers. In addition to its effect on stimulating vesicle trafficking, many studies have demonstrated that PA plays a crucial role in various signaling pathways by binding target proteins and regulating their activity and subcellular localization. Here, we summarize the functional mechanisms and target proteins underlying PA-mediated regulation of cellular signaling, development, hormonal responses, and stress responses in plants.

Structural basis of intramitochondrial phosphatidic acid transport mediated by Ups1-Mdm35 complex.

Ups1 forms a complex with Mdm35 and is critical for the transport of phosphatidic acid (PA) from the mitochondrial outer membrane to the inner membrane. We report the crystal structure of the Ups1-Mdm35-PA complex and the functional characterization of Ups1-Mdm35 in PA binding and transfer. Ups1 features a barrel-like structure consisting of an antiparallel ß-sheet and three α-helices. Mdm35 adopts a three-helical clamp-like structure to wrap around Ups1 to form a stable complex. The ß-sheet and α-helices of Ups1 form a long tunnel-like pocket to accommodate the substrate PA, and a short helix α2 acts as a lid to cover the pocket. The hydrophobic residues lining the pocket and helix α2 are critical for PA binding and transfer. In addition, a hydrophilic patch on the surface of Ups1 near the PA phosphate-binding site also plays an important role in the function of Ups1-Mdm35. Our study reveals the molecular basis of the function of Ups1-Mdm35 and sheds new light on the mechanism of intramitochondrial phospholipid transport by the MSF1/PRELI family proteins.

Phospholipid homeostasis maintains cell polarity, development and virulence in metarhizium robertsii.

The final product of the glycerol phosphate (GP) pathway is triacylglycerol (TAG) that regulates the homeostasis of energy, fatty acids and phospholipids in cells. The enzymes involved in this pathway have been characterized in many model organisms; however, their contributions to fungal infection are largely unclear. In this study, we performed serial deletion of genes in the GP pathway in the insect pathogenic fungus Metarhizium robertsii. The results indicated that a lysophosphatidate acyltransferase mrLPAAT1 was required for fungal growth, cell differentiation, maintenance of cell polarity and virulence. Lipidomic analysis indicated that deletion of mrLPAAT1 resulted in significant increases in TAG, fatty acids and phosphatidylcholine (PC) but decreased phosphatidic acid (PA), phosphatidylethanolamine (PE) and other species of phospholipids when compared to the wild type. Disruption of the isozymatic gene mrLPAAT2, however, resulted in a reduction in PC but not PA in the mutant cells. There were no changes in development and virulence in ΔmrLPAAT2. Phospholipid feeding assays verified that a PE supplement could rescue the cell differentiation defect in ΔmrLPAAT1. The results of this study reveal that cellular phospholipid homeostasis mediated by the GP pathway regulates fungal growth, cell polarity, differentiation and virulence.

Phosphatidic acid interacts with a MYB transcription factor and regulates its nuclear localization and function in Arabidopsis.

Phosphatidic acid (PA) has emerged as a class of cellular mediators involved in various cellular and physiological processes, but little is known about its mechanism of action. Here we show that PA interacts with werewolf (WER), a R2R3 MYB transcription factor involved in root hair formation. The PA-interacting region is confined to the end of the R2 subdomain. The ablation of the PA binding motif has no effect on WER binding to DNA, but abolishes its nuclear localization and its function in regulating epidermal cell fate. Inhibition of PA production by phospholipase Dζ also suppresses WER's nuclear localization, root hair formation, and elongation. These results suggest a role for PA in promoting protein nuclear localization.

Lipidomic profiling analysis reveals the dynamics of phospholipid molecules in Arabidopsis thaliana seedling growth.

High-throughput lipidomic profiling provides a sensitive approach for discovering minor lipid species. By using an advance in electrospray ionization tandem mass spectrometry, a large set of phospholipid molecular species (126 species) with high resolution were identified from Arabidopsis seedling; of them 31 species are newly identified (16 are unique in plants), including 13 species of phosphatidic acid (PA), nine phosphatidylcholine, six phosphatidylinositol and three phosphatidylserine. Further analysis of the lipidomic profile reveals dynamics of phospholipids and distinct species alterations during seedling development. PA molecules are found at the lowest levels in imbibition and follow an increasing trend during seedling growth, while phosphatidylethanolamine (PE) molecules show the opposite pattern with highest levels at imbibition and a general decreasing trend at later stages. Of PA molecular species, 34:2-, 34:3-, 36:4-, 36:5-, 38:3- and 38:4-PA increase during radicle emergence, and 34:2- and 34:3-PA reach highest levels during hypocotyl and cotyledon emergence from the seed coat. Conversely, molecular species of PE show higher levels in imbibition and decrease in later stages. These results suggest the crucial roles of specific molecular species and homeostasis of phospholipid molecules in seedling growth and provide insights into the mechanisms of how phospholipid molecules are involved in regulating plant development.

Trends and Age-Period-Cohort Effect on Incidence of Varicella Under Age 35 - China, 2005-2021.

What is already known about this topic?: Varicella is an acute respiratory infectious disease primarily affecting children. However, recent studies have indicated an increasing susceptibility to varicella among older age groups. What is added by this report?: The findings demonstrate a significant rise in the incidence rate among individuals aged 15-19. Males under 20 years old were found to have a higher risk compared to females, whereas males had a lower risk compared to females aged 20-35 years. What are the implications for public health practice?: This study is the first comparative analysis using varicella data reported between 2005 and 2021 to examine the contributions of age, period, and birth cohort to varicella incidence in China. This study aims to provide a comprehensive analysis of the epidemiological characteristics of varicella in China and identify high-risk groups. The results of this study will contribute valuable information for the development of varicella prevention policies.