Graph Convolutional Network with Self-supervised Learning for Brain Disease Classification.

Brain functional network (BFN) analysis has become a popular method for identifying neurological diseases at their early stages and revealing sensitive biomarkers related to these diseases. Due to the fact that BFN is a graph with complex structure, graph convolutional networks (GCNs) can be naturally used in the identification of BFN, and can generally achieve an encouraging performance if given large amounts of training data. In practice, however, it is very difficult to obtain sufficient brain functional data, especially from subjects with brain disorders. As a result, GCNs usually fail to learn a reliable feature representation from limited BFNs, leading to overfitting issues. In this paper, we propose an improved GCN method to classify brain diseases by introducing a self-supervised learning (SSL) module for assisting the graph feature representation. We conduct experiments to classify subjects with mild cognitive impairment (MCI) and autism spectrum disorder (ASD) respectively from normal controls (NCs). Experimental results on two benchmark databases demonstrate that our proposed scheme tends to obtain higher classification accuracy than the baseline methods.

Morphological Signatures of Neurogenesis and Neuronal Migration in Hypothalamic Vasopressinergic Magnocellular Nuclei of the Adult Rat.

The arginine vasopressin (AVP)-magnocellular neurosecretory system (AVPMNS) in the hypothalamus plays a critical role in homeostatic regulation as well as in allostatic motivational behaviors. However, it remains unclear whether adult neurogenesis exists in the AVPMNS. By using immunoreaction against AVP, neurophysin II, glial fibrillar acidic protein (GFAP), cell division marker (Ki67), migrating neuroblast markers (doublecortin, DCX), microglial marker (Ionized calcium binding adaptor molecule 1, Iba1), and 5'-bromo-2'-deoxyuridine (BrdU), we report morphological evidence that low-rate neurogenesis and migration occur in adult AVPMNS in the rat hypothalamus. Tangential AVP/GFAP migration routes and AVP/DCX neuronal chains as well as ascending AVP axonal scaffolds were observed. Chronic water deprivation significantly increased the BrdU+ nuclei within both the supraaoptic (SON) and paraventricular (PVN) nuclei. These findings raise new questions about AVPMNS's potential hormonal role for brain physiological adaptation across the lifespan, with possible involvement in coping with homeostatic adversities.

Antiplatelet drug ticagrelor suppresses triple negative breast cancer metastasis by targeting PI3K.

Metastatic recurrence is still a major challenge in breast cancer treatment. Patients with triple negative breast cancer (TNBC) develop early recurrence and relapse more frequently. Due to the lack of specific therapeutic targets, new targeted therapies for TNBC are urgently needed. Phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway is one of the active pathways involved in chemoresistance and survival of TNBC, being considered as a potential target for TNBC treatment. Our present study identified ticagrelor, an anti-platelet drug, as a pan-PI3K inhibitor with potent inhibitory activity against four isoforms of class I PI3K. At doses normally used in clinic, ticagrelor showed weak cytotoxicity against a panel of breast cancer cells, but significantly inhibited the migration, invasion and the actin cytoskeleton organization of human TNBC MDA-MB-231 and SUM-159PT cells. Mechanistically, ticagrelor effectively inhibited PI3K downstream mTOR complex 1 (mTORC1) and mTORC2 signaling by targeting PI3K and decreased the protein expression of epithelial-mesenchymal transition (EMT) markers. In vivo, ticagrelor significantly suppressed tumor cells lung metastasis in 4T1 tumor bearing BALB/c mice model and experimental lung metastasis model which was established by tail vein injection of GFP-labeled MDA-MB-231 cells. The above data demonstrated that ticagrelor can inhibit the migration and invasion of TNBC both in vitro and in vivo by targeting PI3K, suggesting that ticagrelor, a pan-PI3K inhibitor, might represent a promising therapeutic agent for the treatment of metastatic TNBC.

Silica nanoparticle design for colorectal cancer treatment: Recent progress and clinical potential.

Colorectal cancer (CRC) is the third most common cancer worldwide and the second most common cause of cancer death. Nanotherapies are able to selectively target the delivery of cancer therapeutics, thus improving overall antitumor efficiency and reducing conventional chemotherapy side effects. Mesoporous silica nanoparticles (MSNs) have attracted the attention of many researchers due to their remarkable advantages and biosafety. We offer insights into the recent advances of MSNs in CRC treatment and their potential clinical application value.

Multi-omic analysis reveals that Bacillus licheniformis enhances pekin ducks growth performance via lipid metabolism regulation.

Introduction: Bacillus licheniformis (B.licheniformis) was widely used in poultry feeds. However, it is still unclear about how B.licheniformis regulates the growth and development of Pekin ducks. Methods: The experiment was designed to clarify the effect and molecular mechanism of B. licheniformis on the lipid metabolism and developmental growth of Pekin ducks through multiomics analysis, including transcriptomic and metabolomic analyses. Results: The results showed that compared with the control group, the addition of 400 mg/kg B. licheniformis could significantly increase the body weight of Pekin ducks and the content of triglyceride (p < 0.05), at the same time, the addition of B. licheniformis could affect the lipid metabolism of liver in Pekin ducks, and the addition of 400 mg/kg B. licheniformis could significantly increase the content of lipoprotein lipase in liver of Pekin ducks. Transcriptomic analysis revealed that the addition of B. licheniformis primarily impacted fatty acid and glutathione, amino acid metabolism, fatty acid degradation, as well as biosynthesis and elongation of unsaturated fatty acids. Metabolomic analysis indicated that B. licheniformis primarily affected the regulation of glycerol phospholipids, fatty acids, and glycerol metabolites. Multiomics analysis demonstrated that the addition of B. licheniformis to the diet of Pekin ducks enhanced the regulation of enzymes involved in fat synthesis via the PPAR signaling pathway, actively participating in fat synthesis and fatty acid transport. Discussion: We found that B. licheniformis effectively influences fat content and lipid metabolism by modulating lipid metabolism-associated enzymes in the liver. Ultimately, this study contributes to our understanding of how B. licheniformis can improve the growth performance of Pekin ducks, particularly in terms of fat deposition, thereby providing a theoretical foundation for its practical application. Conclusion: B. licheniformis can increase the regulation of enzymes related to fat synthesis through PPAR signal pathway, and actively participate in liver fat synthesis and fatty acid transport, thus changing the lipid metabolism of Pekin ducks, mainly in the regulation of glycerol phospholipids, fatty acids and glycerol lipid metabolites.

WhiB-like proteins: Diversity of structure, function and mechanism.

The WhiB-Like (Wbl) proteins are a large family of iron-sulfur (Fe-S) cluster-containing transcription factors exclusively found in the phylum Actinobacteria, including the notable genera like Mycobacteria, Streptomycetes and Corynebacteria. These proteins play pivotal roles in diverse biological processes, such as cell development, redox stress response and antibiotic resistance. Members of the Wbl family exhibit remarkable diversity in their sequences, structures and functions, attracting great attention since their first discovery. This review highlights the most recent breakthroughs in understanding the structural and mechanistic aspects of Wbl-dependent transcriptional regulation.

Salidroside Inhibits α-Amanitin-Induced AML-12 Cell Apoptosis via the Regulation of PINK1/Parkin-Mediated Mitophagy and Mitochondrial Function.

Poisoning caused by the mushroom Amanita phalloides, due to the toxin α-amanitin, accounts for approximately 90% of food poisoning deaths in China with no specific antidotes. To investigate the role of salidroside (Sal) in α-amanitin (α-AMA)-induced mitophagy, mouse liver cells AML-12 were exposed to α-AMA in the presence of Sal or not. Intracellular reactive oxygen species (ROS) levels were measured using a ROS detection kit, mitochondrial activity was evaluated using a mitochondrial red fluorescent probe kit or JC-1 dye, and protein expression levels of PINK1, Parkin, LC3 II, P62, Bax, Bcl-2, Caspase 3, Cleaved-Caspase 3, PARP I, and Cleaved-PARP I were detected through Western blot. Results demonstrated that α-AMA led to increased intracellular ROS levels, cell apoptosis, and decreased mitochondrial membrane potential. Notably, expression levels of mitophagy-related proteins PINK1, Parkin, and LC3 increased significantly while the P62 protein expression decreased remarkably. Furthermore, Sal reversed the α-AMA-induced decrease in cell viability and mitochondrial membrane potential and increase in intracellular ROS level. In addition, Sal promoted expression levels of PINK1, Parkin, and LC3 II while suppressing the Bax/Bcl-2 ratio, Cleaved-Caspase 3, and Cleaved-PARP I as well as P62. The results above proved that salidroside alleviates α-AMA-induced mouse liver cells damage via promoting PINK1/Parkin-mediated mitophagy and reducing cell apoptosis.

Translation and psychometric evaluation of the Chinese version of the Nursing Time Management Scale.

Background: Reasonable and effective time allocation can promote the improvement of medical care service quality. This study aimed to translate, cross-culturally adapt and validate the Chinese Nursing Time Management Scale (NTMS). Methods: Using a cross-sectional survey, 345 clinical nurses were selected from June to September 2023 for a general information questionnaire and Nursing Time Management Scale (NTMS) study. Item analysis, exploratory factor analysis and validation factor analysis were used to verify the reliability and validity of the Chinese version of Nursing Time Management Scale. Results: The Chinese version of the Nurses' Time Management Competency Scale includes 17 entries in 3 dimensions: planning activities and setting goals, coordinating activities and procedures, and organizing nursing activities. The Cronbach's alpha coefficient for the total scale was 0.966. Exploratory factor analysis showed that the cumulative variance contribution of the three male factors was 97.44%. Conclusion: The NTMS has acceptable validity and reliability and can be used to evaluate the nursing time management skills of Chinese clinical nurses.

Nitrification inhibitor chlorate and nitrogen substrates differentially affect comammox Nitrospira in a grassland soil.

Introduction: Through the combined use of two nitrification inhibitors, Dicyandiamide (DCD) and chlorate with nitrogen amendment, this study aimed to investigate the contribution of comammox Nitrospira clade B, ammonia oxidizing bacteria (AOB) and archaea (AOA) to nitrification in a high fertility grassland soil, in a 90-day incubation study. Methods: The soil was treated with nitrogen (N) at three levels: 0 mg-N kg-1 soil, 50 mg-N kg-1 soil, and 700 mg-N kg-1 soil, with or without the two nitrification inhibitors. The abundance of comammox Nitrospira, AOA, AOB, and nitrite oxidising bacteria (NOB) was measured using qPCR. The comammox Nitrospira community structure was assessed using Illumina sequencing. Results and Discussion: The results showed that the application of chlorate inhibited the oxidation of both NH4+ and NO2- in all three nitrogen treatments. The application of chlorate significantly reduced the abundance of comammox Nitrospira amoA and nxrB genes across the 90-day experimental period. Chlorate also had a significant effect on the beta diversity (Bray-Curtis dissimilarity) of the comammox Nitrospira clade B community. Whilst AOB grew in response to the N substrate additions and were inhibited by both inhibitors, AOA showed litle or no response to either the N substrate or inhibitor treatments. In contrast, comammox Nitrospira clade B were inhibited by the high ammonium concentrations released from the urine substrates. These results demonstrate the differential and niche responses of the three ammonia oxidising communities to N substrate additions and nitrification inhibitor treatments. Further research is needed to investigate the specificity of the two inhibitors on the different ammonia oxidising communities.

A Nomogram Prediction Model for Persistent Pulmonary Hypertension of the Newborn in Neonates Hospitalized for the First Time After Birth.

OBJECTIVE: Persistent pulmonary hypertension of the newborn (PPHN) is one of the critical neonatal diseases associated with high morbidity and mortality. This study attempted to conduct a nomogram prediction model for performing early identification of PPHN and providing effective information for clinical practice. METHODS: A total of 456 newborns who first admitted to the hospital after birth were included in the analysis, including 138 newborns with PPHN and 318 newborns without PPHN (as controls). The optimal predictive variables selection was performed based on LASSO (least absolute shrinkage and selection operator) regression and multivariate logistic regression. Using the selected variables, a nomogram prediction model was developed. To validate the model, the model was assessed using the receiver operating characteristic curve, calibration plot, and clinical impact curve. RESULTS: Six predictors, namely, gestational age, neonatal respiratory distress syndrome, the levels of hemoglobin and creatine kinase-MB, gestational thyroid dysfunction, and Pao2, were identified by LASSO and multivariate logistic regression analysis from the original 30 variables studied. The constructed model, using these predictors, exhibited favorable predictive ability for PPHN, with an area under the receiver operating characteristic of 0.897 (sensitivity = 0.876, specificity = 0.785) in the training set and 0.871 (sensitivity = 0.902, specificity = 0.695) in the validation set, and was well calibrated, as indicated by the PHosmer-Lemeshow test values of 0.233 and 0.876 for the training and validation sets, respectively. CONCLUSIONS: The model included gestational age, neonatal respiratory distress syndrome, the levels of hemoglobin and creatine kinase-MB, gestational thyroid dysfunction, and Pao2 had good prediction performance for predicting PPHN among newborns first admitted to the hospital after birth.

Polymeric monolithic columns based on natural wood for rapid purification of targeted protein.

With multiscale hierarchical structure, wood is suitable for a range of high-value applications, especially as a chromatographic matrix. Here, we have aimed to provide a weak anion-exchange polymeric monolithic column based on natural wood with high permeability and stability for effectively separating the targeted protein. The wood-polymeric monolithic column was synthesized by in situ polymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in wood, and coupled with diethylaminoethyl hydrochloride. The wood-polymeric monolithic column can be integrated with fast-protein liquid chromatography for large-scale protein purification. According to the results, the wood-polymeric monolithic column showed high hydrophilicity, permeability and stability. Separation experiments verified that the wood-polymeric monolithic column could purify the targeted protein (spike protein of SARS-COV-2 and ovalbumin) from the mixed proteins by ion exchange, and the static adsorption capacity was 33.04 mg mL-1 and the dynamic adsorption capacity was 24.51 mg mL-1. In addition, the wood-polymerized monolithic column had good stability, and a negligible decrease in the dynamic adsorption capacity after 20 cycles. This wood-polymerized monolithic column can provide a novel, efficient, and green matrix for monolithic chromatographic columns.

Whole Genome Sequence Analysis of Two Oxacillin-Resistant and mecA-Positive Strains of Staphylococcus haemolyticus Isolated from Ear Swab Samples of Patients with Otitis Media.

Objective: Staphylococcus haemolyticus can cause a series of infections including otitis media (OM), and the oxacillin-resistant S. haemolyticus has become a serious health concern. This study aimed to investigate the genomic characteristics of two strains of oxacillin-resistant and mecA-positive S. haemolyticus isolated from the samples of ear swabs from patients with OM and explore their acquired antibiotic resistance genes (ARGs) and the mobile genetic elements (MGEs). Methods: Two oxacillin-resistant S. haemolyticus strains, isolated from ear swab samples of patients with OM, underwent antimicrobial susceptibility evaluation, followed by whole-genome sequencing. The acquired ARGs and the MGEs carried by the ARGs, harbored by the genomes of two strains of S. haemolyticus were identified. Results: The two strains of oxacillin-resistant S. haemolyticus (strain SH1275 and strain SH9361) both carried the genetic contexts of mecA with high similarity with the SCCmec type V(5C2&5) subtype c. Surprisingly, the chromosomal aminoglycoside resistance gene aac(6')-aph(2") harbored by S. haemolyticus strain SH936 was flanked by two copies of IS256, forming the IS256-element (IS256-GNAT-[aac(6')-aph(2")]-IS256), which was widely present in strains of both Staphylococcus and Enterococcus genus. Furthermore, the two strains of oxacillin-resistant and MDR S. haemolyticus were found to harbor antimicrobial resistance plasmids, including one 26.9-kb plasmid (pSH1275-2) containing msr(A)-mph(C)) and qacA, one mobilizable plasmid pSH1275-3 harboring vga(A)LC, one plasmid (pSH9361-1) carrying erm(C), and one plasmid (pSH9361-2) carrying qacJ. Conclusion: The systematic analysis of whole-genome sequences provided insights into the mobile genetic elements responsible for multi-drug resistance in these two strains of oxacillin-resistant and mecA-positive S. haemolyticus, which will assist clinicians in devising precise, personalized, and clinical therapeutic strategies for treating otitis media caused by multi-drug resistant S. haemolyticus.

Stretchable and Transparent Heaters Based on Hydrophobic Ionogels with Superior Moisture Insensitivity.

Flexible and stretchable transparent heaters (THs) have been widely used in various applications, including deicing and defogging of flexible screens as well as thermotherapy pads. Ionic THs based on ionogels have emerged as a promising alternative to conventional electronic THs due to their unique advantages in terms of transparency-conductance conflict, uniform heating, and interfacial adhesion. However, the commonly used hydrophilic ionogels inevitably introduce a moisture-sensitive issue. In this work, we present a stretchable and transparent hydrophobic ionogel-based heater that utilizes ionic current-induced Joule heating under high-frequency alternating current. This ionogel-based TH exhibits exceptional multifunctional properties with low hysteresis, a fracture strain of 840%, transmittance of 93%, conductivity of 0.062 S m-1, temperature resistance up to 165 °C, voltage resistance up to 120 V, heating rate of 0.1 °C s-1, steady-state temperature at 115 °C, and uniform heating even when bent or stretched (up to 200%). Furthermore, it maintains its heating performance when it is directly exposed to water. This hydrophobic ionogel-based TH expands the range of materials available for ionic THs and paves the way for their practical applications.

Visual outcomes and patient satisfaction after implantations of three types of presbyopia-correcting intraocular lenses that have undergone corneal refractive surgery.

This prospective, non-randomized, comparative study aimed to compare the visual outcomes and patient satisfaction after implantations of three presbyopia-correcting intraocular lenses (IOLs) after myopic refractive surgery. It was conducted from January 2020 to December 2021 in Shanghai Heping Eye Hospital. Patients were divided into three groups based on the type of IOL implanted. The visual acuity, refractive stability, high-order aberrations, objective visual quality, spectacle independence, and visual function index 14 questionnaire scores of the three groups were compared. This study included 78 eyes of 39 patients: 26 eyes with 839MP, 26 eyes with MF30, and 26 eyes with ZXR00. Uncorrected distance visual acuity improved significantly for all three groups. For a pupil diameter of 4.0 mm, the spherical aberrations of the three groups were 0.33 ± 0.16 µ, 0.50 ± 0.08 µ, and 0.39 ± 0.10 µ, respectively. The spectacle independence for distance vision was over 90% in each group; for near vision, it was only 25% for the ZXR00 group. All three types of presbyopia-correcting IOLs improved visual quality in post-LASIK or PRK patients. However, the high incidence of photic phenomena after presbyopia-correcting IOL implantation in patients who have undergone myopic LASIK should not be neglected.

Streptomyces-triggered coordination between rhizosphere microbiomes and plant transcriptome enables watermelon Fusarium wilt resistance.

The use of microbial inoculant is a promising strategy to improve plant health, but their efficiency often faces challenges due to difficulties in successful microbial colonization in soil environments. To this end, the application of biostimulation products derived from microbes is expected to resolve these barriers via direct interactions with plants or soil pathogens. However, their effectiveness and mechanisms for promoting plant growth and disease resistance remain elusive. In this study, we showed that root irrigation with the extracts of Streptomyces ahygroscopicus strain 769 (S769) solid fermentation products significantly reduced watermelon Fusarium wilt disease incidence by 30% and increased the plant biomass by 150% at a fruiting stage in a continuous cropping field. S769 treatment led to substantial changes in both bacterial and fungal community compositions, and induced a highly interconnected microbial association network in the rhizosphere. The root transcriptome analysis further suggested that S769 treatment significantly improved the expression of the MAPK signalling pathway, plant hormone signal transduction and plant-pathogen interactions, particular those genes related to PR-1 and ethylene, as well as genes associated with auxin production and reception. Together, our study provides mechanistic and empirical evidences for the biostimulation products benefiting plant health through coordinating plant and rhizosphere microbiome interaction.

Solamargine Induces Hepatocellular Carcinoma Cell Apoptosis and Ferroptosis via Regulating STAT1/MTCH1 Axis.

BACKGROUND: Solamargine (SM) has been shown to play anti-tumor role in hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms of SM in HCC progression deserve further exploration. METHODS: HCC cell proliferation and apoptosis were assessed by cell counting kit 8 assay, colony formation assay and flow cytometry. Ferroptosis was evaluated by detecting the levels of Fe2+, iron, MDA, ROS and GSH in HCC cells. In addition, mitochondrial carrier 1 (MTCH1) mRNA level was detected by quantitative real-time PCR. Western blot was used to test MTCH1 and signal transduction and activation of transcription 1 (STAT1) protein levels. Dual-luciferase reporter assay was employed to analyze the interaction between STAT1 and MTCH1. A mouse xenograft model was also constructed to explore the role of SM in vivo. RESULTS: SM could potentially suppress HCC cell growth by inducing ferroptosis. MTCH1 was highly expressed in HCC tissues and cells, and its silencing inhibited HCC cell proliferation, promoted apoptosis and ferroptosis. MTCH1 expression was reduced by SM, and its overexpression reversed SM-induced HCC cell apoptosis and ferroptosis. Furthermore, STAT1 facilitated MTCH1 transcription and promoted its expression. Besides, STAT1 expression could be reduced by SM, and its overexpression abolished the decreasing effect of SM on MTCH1 expression. In vivo, SM suppressed HCC tumor growth by reducing MTCH1 expression. CONCLUSION: SM promoted HCC cell apoptosis and ferroptosis via the STAT1/MTCH1 axis.

AOB Nitrosospira cluster 3a.2 (D11) dominates N2O emissions in fertilised agricultural soils.

Ammonia-oxidation process directly contribute to soil nitrous oxide (N2O) emissions in agricultural soils. However, taxonomy of the key nitrifiers (within ammonia oxidising bacteria (AOB), archaea (AOA) and complete ammonia oxidisers (comammox Nitrospira)) responsible for substantial N2O emissions in agricultural soils is unknown, as is their regulation by soil biotic and abiotic factors. In this study, cumulative N2O emissions, nitrification rates, abundance and community structure of nitrifiers were investigated in 16 agricultural soils from major crop production regions of China using microcosm experiments with amended nitrogen (N) supplemented or not with a nitrification inhibitor (nitrapyrin). Key nitrifier groups involved in N2O emissions were identified by comparative analyses of the different treatments, combining sequencing and random forest analyses. Soil cumulative N2O emissions significantly increased with soil pH in all agricultural soils. However, they decreased with soil organic carbon (SOC) in alkaline soils. Nitrapyrin significantly inhibited soil cumulative N2O emissions and AOB growth, with a significant inhibition of the AOB Nitrosospira cluster 3a.2 (D11) abundance. One Nitrosospira multiformis-like OTU phylotype (OTU34), which was classified within the AOB Nitrosospira cluster 3a.2 (D11), had the greatest importance on cumulative N2O emissions and its growth significantly depended on soil pH and SOC contents, with higher growth at high pH and low SOC conditions. Collectively, our results demonstrate that alkaline soils with low SOC contents have high N2O emissions, which were mainly driven by AOB Nitrosospira cluster 3a.2 (D11). Nitrapyrin can efficiently reduce nitrification-related N2O emissions by inhibiting the activity of AOB Nitrosospira cluster 3a.2 (D11). This study advances our understanding of key nitrifiers responsible for high N2O emissions in agricultural soils and their controlling factors, and provides vital knowledge for N2O emission mitigation in agricultural ecosystems.

Bioinspired and biomimetic strategies for inflammatory bowel disease therapy.

Inflammatory bowel disease (IBD) is an idiopathic chronic inflammatory bowel disease with high morbidity and an increased risk of cancer or death, resulting in a heavy societal medical burden. While current treatment modalities have been successful in achieving long-term remission and reducing the risk of complications, IBD remains incurable. Nanomedicine has the potential to address the high toxic side effects and low efficacy in IBD treatment. However, synthesized nanomedicines typically exhibit some degree of immune rejection, off-target effects, and a poor ability to cross biological barriers, limiting the development of clinical applications. The emergence of bionic materials and bionic technologies has reshaped the landscape in novel pharmaceutical fields. Biomimetic drug-delivery systems can effectively improve biocompatibility and reduce immunogenicity. Some bioinspired strategies can mimic specific components, targets or immune mechanisms in pathological processes to produce targeting effects for precise disease control. This article highlights recent research on bioinspired and biomimetic strategies for the treatment of IBD and discusses the challenges and future directions in the field to advance the treatment of IBD.

Microbial species pool-mediated diazotrophic community assembly in crop microbiomes during plant development.

Plant-associated diazotrophs strongly relate to plant nitrogen (N) supply and growth. However, our knowledge of diazotrophic community assembly and microbial N metabolism in plant microbiomes is largely limited. Here we examined the assembly and temporal dynamics of diazotrophic communities across multiple compartments (soils, epiphytic and endophytic niches of root and leaf, and grain) of three cereal crops (maize, wheat, and barley) and identified the potential N-cycling pathways in phylloplane microbiomes. Our results demonstrated that the microbial species pool, influenced by site-specific environmental factors (e.g., edaphic factors), had a stronger effect than host selection (i.e., plant species and developmental stage) in shaping diazotrophic communities across the soil-plant continuum. Crop diazotrophic communities were dominated by a few taxa (~0.7% of diazotrophic phylotypes) which were mainly affiliated with Methylobacterium, Azospirillum, Bradyrhizobium, and Rhizobium. Furthermore, eight dominant taxa belonging to Azospirillum and Methylobacterium were identified as keystone diazotrophic taxa for three crops and were potentially associated with microbial network stability and crop yields. Metagenomic binning recovered 58 metagenome-assembled genomes (MAGs) from the phylloplane, and the majority of them were identified as novel species (37 MAGs) and harbored genes potentially related to multiple N metabolism processes (e.g., nitrate reduction). Notably, for the first time, a high-quality MAG harboring genes involved in the complete denitrification process was recovered in the phylloplane and showed high identity to Pseudomonas mendocina. Overall, these findings significantly expand our understanding of ecological drivers of crop diazotrophs and provide new insights into the potential microbial N metabolism in the phyllosphere.IMPORTANCEPlants harbor diverse nitrogen-fixing microorganisms (i.e., diazotrophic communities) in both belowground and aboveground tissues, which play a vital role in plant nitrogen supply and growth promotion. Understanding the assembly and temporal dynamics of crop diazotrophic communities is a prerequisite for harnessing them to promote plant growth. In this study, we show that the site-specific microbial species pool largely shapes the structure of diazotrophic communities in the leaves and roots of three cereal crops. We further identify keystone diazotrophic taxa in crop microbiomes and characterize potential microbial N metabolism pathways in the phyllosphere, which provides essential information for developing microbiome-based tools in future sustainable agricultural production.

Triplet-constrained deep hashing for chest X-ray image retrieval in COVID-19 assessment.

Radiology images of the chest, such as computer tomography scans and X-rays, have been prominently used in computer-aided COVID-19 analysis. Learning-based radiology image retrieval has attracted increasing attention recently, which generally involves image feature extraction and finding matches in extensive image databases based on query images. Many deep hashing methods have been developed for chest radiology image search due to the high efficiency of retrieval using hash codes. However, they often overlook the complex triple associations between images; that is, images belonging to the same category tend to share similar characteristics and vice versa. To this end, we develop a triplet-constrained deep hashing (TCDH) framework for chest radiology image retrieval to facilitate automated analysis of COVID-19. The TCDH consists of two phases, including (a) feature extraction and (b) image retrieval. For feature extraction, we have introduced a triplet constraint and an image reconstruction task to enhance discriminative ability of learned features, and these features are then converted into binary hash codes to capture semantic information. Specifically, the triplet constraint is designed to pull closer samples within the same category and push apart samples from different categories. Additionally, an auxiliary image reconstruction task is employed during feature extraction to help effectively capture anatomical structures of images. For image retrieval, we utilize learned hash codes to conduct searches for medical images. Extensive experiments on 30,386 chest X-ray images demonstrate the superiority of the proposed method over several state-of-the-art approaches in automated image search. The code is now available online.