Biology subjects

Xu, D.

Publications and source records attributed to Xu, D..

At least 163 records · Page 9Linked to original sources

bioRxiv2022

Population genomics unravels the Holocene history of Triticum-Aegilops species

Deep knowledge of crop biodiversity is essential to improve global food security. Despite bread wheat serving as a keystone crop worldwide, the population history of bread wheat and its wild relatives (a.k.a. wheats) remains elusive. By analyzing whole-genome sequences of 795 wheats, we found that bread wheat originated southwest of the Caspian Sea [~]11,700 years ago and underwent a slow speciation process, lasting [~]3,300 years due to persistent gene flow from wild relatives. Soon after, bread wheat spread across Eurasia and reached Europe, South Asia, and East Asia [~]7,000 to [~]5,000 years ago, shaping a diversified but occasionally convergent adaptive landscape of bread wheat in novel environments. Opposite to cultivated wheat, wild wheat populations have declined by [~]82% in the past [~]2,000 years due to the food choice shift of humans, and likely continue to drop because of the changing climate. These findings will guide future efforts in protecting and utilizing wheat biodiversity to improve global food security.

genetics↗

bioRxiv2022

Antiviral roles of interferon regulatory factor (IRF)-1, 3 and 7 against human coronavirus infection

Interferon regulatory factors (IRFs) are key elements of antiviral innate responses that regulate transcription of interferons (IFNs) and IFN-stimulated genes (ISGs). As many human coronaviruses are known to be sensitive to IFN, antiviral roles of IRFs are yet to be fully understood. TypeI or II IFN treatment protected MRC5 cells from infection of human coronavirus 229E, but not human coronavirus OC43. Infection of 229E or OC43 efficiently upregulated ISGs, indicating that antiviral transcription is not suppressed during their infection. Antiviral IRFs, IRF1, IRF3 and IRF7, were activated in cells infected with 229E, OC43 or severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2). RNAi knockdown and overexpression of the IRFs demonstrated that IRF1 and IRF3 have antiviral property against OC43 while only IRF3 and IRF7 are effective to restrict 229E infection. Our study demonstrates that IRF3 plays critical roles against infection of human coronavirus 229E and OC43, which may be an anti-human coronavirus therapeutic target.

microbiology↗

bioRxiv2022

Influence of residual microbial nucleic acid in instruments for hip joint arthroplasty on false-positive results of metagenomic sequencing

The purpose of this study was to analyze the effect of residual microbial nucleic acid in instruments for hip joint arthroplasty on false-positive sequencing results. Samples were taken from 3 different acetabular reamer for hip arthroplasty in 7 different hospitals. The whole process was strictly aseptic, metagenomic next-generation sequencing (mNGS) was performed according to standard operating procedures. The sterility of instruments was confirmed by culture method. The sequencing results of specimens from different hospitals were compared to analyze the difference of background bacteria. Bioinformatics analysis and visualization were presented through R language. A total of 26 samples were processed by mNGS, including 24 instrument swab samples, 1 blank swab control, and 1 blank water control. 254,314,707 reads were sequenced in all samples. The results showed that 1.13% of Clean Reads can be matched to pathogenic microorganism genomes, of which bacterial sequences account for 87.48%, fungal sequences account for 11.18%, parasite sequences account for 1.26%, and virus sequences account for 0.06%. The results of PCA (Principal Component Analysis) demonstrated that the distribution of bacteria on the surface of instruments was significantly different between medical institutions. Through the Venn diagram, it was found that 465 species of bacteria in all region hospitals, Liaocheng Peoples Hospital had a maximum of 340 species of bacteria, followed by Guanxian County Peoples Hospital with 169 species. The clustering heat map illustrated that the distribution of bacterial groups in three different instrument samples in the same hospital was basically the same, and the bacterial genera varied significantly among hospitals. The residual microbial nucleic acid fragments are mainly bacterial DNA and represent differences in different medical institutions, The establishment of independent background bacterial libraries in different medical institutions can effectively improve the accuracy of mNGS diagnosis and help to exclude background microorganisms interference.

genomics↗

bioRxiv2022

Discovery of novel therapeutic targets in cancer using patient-specific gene regulatory networks.

Most cancer types lack effective targeted therapeutic options and in cancers where first-line targeted therapies are available, treatment resistance is a huge challenge. Recent technological advances enable the use of ATAC-seq and RNA-seq on patient biopsies in a high-throughput manner. Here we present a computational approach that leverages these datasets to identify novel drug targets based on tumor lineage. We constructed patient-specific gene regulatory networks for 371 patients of 22 cancer types using machine learning approaches trained using three-dimensional genomic data for enhancer to promoter contacts. Next, we identify the key transcription factors (TFs) in these networks, which are used to identify therapeutic vulnerabilities either by direct targeting of TFs or proteins that they co-operate with. We validate four novel candidates identified for neuroendocrine, liver and renal cancers, which have a dismal prognosis with current therapeutic options. We present a novel approach to use the increasing amounts of functional genomics data from patient biospecimens for identification of novel drug targets.

systems biology↗

bioRxiv2022

Molecular insights into the MCM8/9 helicase complex in DNA unwinding and translocation

MCM8 and MCM9 form a functional helicase complex (MCM8/9) that plays an essential role in DNA homologous recombination repair for DNA double-strand break. However, the structural characterization of MCM8/9 for DNA binding/unwinding remains unclear. Here, we report structures of the MCM8/9 complex using cryo-electron microscopy single particle analysis. The structures reveal that MCM8/9 is arranged into a heterohexamer through a three-fold symmetry axis, creating a central channel that accommodates DNA. Multiple characteristic hairpins from the N-terminal oligosaccharide/oligonucleotide (OB) domains of MCM8/9 protrude into the central channel and serve to unwind the duplex DNA. When activated by HROB, the structure of MCM8/9s N-tier ring converts its symmetry from C3 to C1 with a conformational change that expands the MCM8/9s trimer interface. Moreover, our structural dynamic analyses revealed that the flexible C-tier ring exhibited rotary motions relative to the N-tier ring, which is required for the unwinding ability of MCM8/9. In summary, our structural and biochemistry study provide a basis for understanding the DNA unwinding mechanism of MCM8/9 helicase in homologous recombination.

biophysics↗

bioRxiv2022

GFAP: ultra-fast and accurate gene functional annotation software for plants

Sequence alignment is the basis of gene functional annotation for unknow sequences. Selecting closely related species as the reference species should be an effective way to improve the accuracy of gene annotation for plants, compared with only based on one or some model plants. Therefore, limited species number in previous software or website is disadvantageous for plant gene annotation. Here, we collected the protein sequences of 236 plant species with known genomic information from 63 families. After that, these sequences were annotated by pfam, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases to construct our databases. Furthermore, we developed the software, Gene Annotation Software for Plants (GFAP), to perform gene annotation using our databases. GFAP, an open-source software running on Windows and MacOS systems, is an efficient and network independent tool. GFAP can search the protein domain, GO and KEGG information for 43000 genes within 4 minutes. In addition, GFAP can also perform the sequence alignment, statistical analysis and drawing. The website of https://gitee.com/simon198912167815/gfap-database provides the software, databases, testing data and video tutorials for users. GFAP contained large amount of plant-species information. We believe that it will become a powerful tool in gene annotation using closely related species for phytologists.

bioinformatics↗

bioRxiv2021

High density single-unit human cortical recordings using the Neuropixels probe

A fundamental unit of neural computation is the action potential. While significant advances have been made in the ability to sample action potentials of large numbers of individual neurons in animal models, translation of these methodologies to humans has been lacking due to clinical time constraints, electrical noise in the operating room, and reliability of the methodology. Here we present a reliable method for intraoperative recording of dozens of neurons in humans using the Neuropixels probe, yielding up to [~]100 simultaneously-recorded single-units (n=596 across 11 recordings in 8 participants). Most single-units were active within 1 minute of reaching target depth, compatible with clinical time constraints. Cell pairs active close in time were spatially closer in most recordings, demonstrating the power to resolve complex cortical dynamics. Altogether, this approach provides access to population single-unit activity across the depth of human neocortex at scales previously only accessible in animal models. HighlightsO_LISingle units in 8 patients, yielding 596 putative single units across 11 recordings C_LIO_LIThe majority of putative neurons fire at least 1 spike within one minute after reaching target depth C_LIO_LIPutative neurons take longer to fire at least one spike in anesthetized compared to awake participants C_LIO_LICell-pairs that fire action potentials close in time are spatially closer together than those fire further apart in time C_LI

neuroscience↗

bioRxiv2021

Develop an efficient and specific AAV-based labeling system for Muller glia in mice

Cell degeneration in the retina leads to several ocular diseases and vision loss. Considerable research efforts focus on reprogramming Muller glia (MG) into functional cells to rescue vision as a promising therapeutic strategy, although whether MG can convert into functional bipolar cells, retinal ganglia cells (RGCs), rods or cones in mammals remains controversial. The broad applicability of tracking MG differentiation thus presents a need for improved labeling efficiency and specificity. Here, we compared AAV-based labeling strategies with conventional lineage-tracking by crossing transgenic mouse lines. We found that reporter expression was weak and not MG-specific in mGFAP-Cre transgenic mice. Different AAV serotypes showed a range of efficiency and specificity in labeling MG, leading us to optimize a human GFAP-Cre reporter system packaged in the AAV9 serotype with the WPRE (WPRE, woodchuck hepatitis virus post-transcriptional regulatory element) removed. The hGFAP-Cre- {Delta}WPRE reporter could label 20-73.8% MGs, with non-specific RGC labeling rates ranging from 0-0.08% at doses of 1 x 108 to 1010 vector genomes (vg) per eye, an approximate 40-fold reduction compared with the AAV9-hGFAP-Cre-WPRE labeling system. Furthermore, we validated the availability of the label system to trace MG reprogramming and also detected false-positive results reported previously. The AAV9-hGFAP-Cre-{Delta}WPRE system thus represents a highly efficient and specific labeling system for MG, providing a valuable tool for tracking cell fate in vivo.

neuroscience↗

bioRxiv2021

Recapitulation of patient-specific 3D chromatin conformation using machine learning and validation of identified enhancer-gene targets

Regulatory networks containing enhancer to gene edges define cellular state and their rewiring is a hallmark of cancer. While efforts, such as ENCODE, have revealed these networks for reference tissues and cell-lines by integrating multi-omics data, the same methods cannot be applied for large patient cohorts due to the constraints on generating ChIP-seq and three-dimensional data from limited material in patient biopsies. We trained a supervised machine learning model using genomic 3D signatures of physical enhancer-gene connections that can predict accurate connections using data from ATAC-seq and RNA-seq assays only, which can be easily generated from patient biopsies. Our method overcomes the major limitations of correlation-based approaches that cannot distinguish between distinct target genes of given enhancers in different samples, which is a hallmark of network rewiring in cancer. Our model achieved an AUROC (area under receiver operating characteristic curve) of 0.91 and, importantly, can distinguish between active regulatory elements with connections to target genes and poised elements with no connections to target genes. Our predicted regulatory elements are validated by multi-omics data, including histone modification marks from ENCODE, with an average specificity of 0.92. Application of our model on chromatin accessibility and transcriptomic data from 400 cancer patients across 22 cancer types revealed novel cancer-type and subtype-specific enhancer-gene connections for known cancer genes. In one example, we identified two enhancers that regulate the expression of ESR1 in only ER+ breast cancer (BRCA) samples but not in ER-samples. These enhancers are predicted to contribute to the high expression of ESR1 in 93% of ER+ BRCA samples. Functional validation using CRISPRi confirms that inhibition of these enhancers decreases the expression of ESR1 in ER+ samples.

cancer biology↗

bioRxiv2021

RIF1-ASF1-mediated high-order chromatin structure safeguards genome integrity

The 53BP1-RIF1 pathway antagonizes resection of DNA broken ends and confers PARP inhibitor sensitivity on BRCA1-mutated tumors. However, it is unclear how this pathway suppresses initiation of resection. Here, we identify ASF1 as a partner of RIF1 via an interacting manner similar to its interactions with histone chaperones CAF-1 and HIRA. ASF1 is recruited to distal chromatin flanking DNA breaks by 53BP1-RIF1 and promotes non-homologous end joining (NHEJ) using its histone chaperone activity. Epistasis analysis shows that ASF1 acts in the same NHEJ pathway as RIF1, but via a parallel pathway with the shieldin complex, which suppresses resection after initiation. Moreover, defects in end resection and homologous recombination (HR) in BRCA1- deficient cells are largely suppressed by ASF1 deficiency. Mechanistically, ASF1 compacts adjacent chromatin by heterochromatinization to protect broken DNA ends from BRCA1-mediated resection. Taken together, our findings identified a RIF1-ASF1 histone chaperone complex that promotes changes in high-order chromatin structure to stimulate the NHEJ pathway for DSB repair.

molecular biology↗

bioRxiv2021

Biological network inference from single-cell multi-omics data using heterogeneous graph transformer

We present DeepMAPS (Deep learning-based Multi-omics Analysis Platform for Single-cell data) for biological network inference from single-cell multi-omics (scMulti-omics). DeepMAPS includes both cells and genes in a heterogeneous graph to simultaneously infer cell-cell, cell-gene, and gene-gene relations. The multi-head attention mechanism in a graph transformer considers the heterogeneous relation among cells and genes within both local and global context, making DeepMAPS robust to data noise and scale. We benchmarked DeepMAPS on 18 scMulti-omics datasets for cell clustering and biological network inference, and the results showed that our method outperformed various existing tools. We further applied DeepMAPS on lung tumor leukocyte CITE-seq data and matched diffuse small lymphocytic lymphoma scRNA-seq and scATAC-seq data. In both cases, DeepMAPS showed competitive performance in cell clustering and predicted biologically meaningful cell-cell communication pathways based on the inferred gene networks. Note that we deployed a webserver using DeepMAPS implementation equipped with multiple functions and visualizations to improve the feasibility and reproducibility of scMulti-omics data analysis. Overall, DeepMAPS represents a heterogeneous graph transformer for single-cell study and may benefit the use of scMulti-omics data in various biological systems.

bioinformatics↗

bioRxiv2021

Genotyping of structural variation using PacBio high-fidelity sequencing

BackgroundStructural variations (SVs) pervade the genome and contribute substantially to the phenotypic diversity of species. However, most SVs were ineffectively assayed because of the complexity of plant genomes and the limitations of sequencing technologies. Recent advancement of third-generation sequencing technologies, particularly the PacBio high-fidelity (HiFi) sequencing, which generates both long and highly accurate reads, offers an unprecedented opportunity to characterize SVs and reveal their functionality. Since HiFi sequencing is new, it is crucial to evaluate HiFi reads in SV detection before applying the technology at scale. ResultsWe sequenced wheat genomes using HiFi, then conducted a comprehensive evaluation of SV detection using mainstream long-read aligners and SV callers. The results showed the accuracy of SV discovery depends more on aligners rather than callers. For aligners, pbmm2 and NGMLR provided the most accurate results while detecting deletion and insertion, respectively. Likewise, cuteSV and SVIM achieved the best performance across all SV callers. We demonstrated that the combination of the aligners and callers mentioned above is optimal for SV detection. Furthermore, we evaluated the impact of sequencing depth on the accuracy of SV detection. The results showed that low-coverage HiFi sequencing is capable of generating high-quality SV genotyping. ConclusionsThis study provides a robust benchmark of SV discovery with HiFi reads, showing the remarkable potential of long-read sequencing to investigate structural variations in plant genomes. The high accuracy SV discovery from low-coverage HiFi sequencing indicates that skim HiFi sequencing is an ideal approach to study structural variations at the population level.

bioinformatics↗

bioRxiv2021

Diversity, function and evolution of marine microbe genomes

Trillions of marine bacterial, archaeal and viral species contribute to the majority diversity of life on Earth. In the current study, we have done a comprehensive review of all the published studies of marine microbiome by re-analyzing most of the available high throughput sequencing data. We collected 17.59 Tb sequencing data from 8,165 metagenomic and prokaryotic samples, and systematically evaluated the genome characters, including genome size, GC content, phylogeny, and the functional and ecological roles of several typical phyla. A genome catalogue of 9,070 high quality genomes and a gene catalogue including 156,209,709 genes were constructed, representing the most integrate marine prokaryotic datasets till now. The genome size of Alphaproteobacteria and Actinobacteria was significant correlated to their GC content. A total of 44,322 biosynthetic gene clusters distributed in 53 types were detected from the reconstructed marine prokaryotic genome catalogue. Phylogenetic annotation of the 8,380 bacterial and 690 archaeal species revealed that most of the known bacterial phyla (99/111), including 62 classes and 181 orders, and four extra unclassified genomes from two candidate novel phyla were detected. In addition, taxonomically unclassified species represented a substantial fraction of 64.56% and 80.29% of the phylogenetic diversity of Bacteria and Archaea respectively. The genomic and ecological features of three groups of Cyanobacteria, luminous bacteria and methane-metabolizing archaea, including inhabitant preference, geolocation distribution and others were through discussed. Our database provides a comprehensive resource for marine microbiome, which would be a valuable reference for studies of marine life origination and evolution, ecology monitor and protection, bioactive compound development.

microbiology↗

bioRxiv2021

Deactivation of SARS-CoV-2 surrogate porcine epidemic diarrhea virus with electron beam irradiation under the cold chain transportation condition

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has prevailed all over the world and emerged as a significant public health emergency. The rapid outbreak of SARS-CoV-2 is largely due to its high transmission capacity. Studies implied that the cold chain logistics would be a potential route for the spread of SARS-CoV-2. The low temperature condition of the cold chain is conducive to survival and transmission of virus. Thus, the virus disinfection in cold chain should not be neglected for controlling COVID-19. However, due to the low temperature feature of the cold-chain, the virus disinfecting methods suitable in cold chain are limited. Here the high-energy electron beam irradiation is proposed to disinfect the SARS-CoV-2 in cold chain logistics. We evaluated the impact of high-energy electron beam irradiation on porcine epidemic diarrhea virus (PEDV), an enveloped virus surrogate for SARS-CoV-2, and explored the possible mechanism of the action of high-energy electron beam irradiation on PEDV. The irradiation dose of 10 kGy inactivated 98.1 % PEDV on the both top and bottom surfaces of various packaging materials under cold chain frozen condition. High-energy electron beam inactivated PEDV by inducing damages on viral genome or even capsid.

microbiology↗

bioRxiv2021

Structural basis of substrate recognition and translocation by human ABCD1

Human ATP-binding cassette (ABC) transporter ABCD1 transports CoA esters of saturated/monounsaturated very long chain fatty acid from cytosol to the peroxisome for {beta}-oxidation. Dysfunction of human ABCD1 usually causes the severe progressive genetic disorder X-linked adrenoleukodystrophy, which eventually affects the adrenal glands and/or the central nervous system. Here, we report three cryo-EM structures of human ABCD1 in various states. The apo-form ABCD1 at 3.53 [A] resolution adopts an inward-facing conformation, harboring a phosphatidyl ethanolamine (PE) molecule at each lateral entry of substrate cavity. In the substrate-bound ABCD1 structure at 3.59 [A] resolution, two molecules of C22:0-CoA (one of the physiological substrates of ABCD1) is symmetrically bound to the transmembrane domains (TMDs). Each C22:0-CoA adopts an unpresented L-shape configuration: the CoA portion inserts into a polar pocket at the TMD at a pose parallel to the membrane plane, whereas the acyl chain portion perpendicular to membrane plane is embedded in a hydrophobic pocket at the opposite TMD. Upon binding the two C22:0-CoA molecules, which resemble a pair of hinges crossing the two TMDs, the two nucleotide-binding domains (NBDs) of ABCD1 approach towards each other. Addition ATP to the substrate-bound ABCD1 enabled us to reveal an ATP-bound structure at 2.79 [A], which shows an outward-facing conformation with the dimerized NBDs succeeding substrate release. These three structures combined with biochemical assays exhibit a snapshot of ABCD1-mediated substrate recognition, translocation and release. These findings provide the structural insights into the transport mechanism of ABC transporters that transport amphipathic molecules with long acyl chains.

biophysics↗

bioRxiv2021

Effects of short-term salinity exposure on haemolymph osmolality, gill morphology and Na+/K+ - ATPase activity in Solenaia oleivora

In order to explore the physiological reaction to hyperosmotic environment, Solenaia oleivora were exposed to 2.23{per thousand} salinity. In 48h, the hemolymph osmolality kept increasing, and the hemolymph protein concentration increased in the first 6h and then decreased significantly, while the free amino acid content increased in the first 24h and then kept stable (P < 0.05). The activity of Na+/K+-ATPase at 0h was significantly higher than other times in most organs except intestine, which was highest at 3h (P < 0.05). The ions concentration were also influenced. The concentration of Na+ rose in haemolymph, axe foot and intestine, but decreased in gill and hepatopancreas. In hemolymph, gill, hepatopancreases and adductor muscle, the K+ concentration was the highest at 0h, while in axe foot and intestine, it showed a positive tendency. The concentration of Cl- in haemolymph, adductor muscle, intestine and axe foot were positively correlated with treatment time, while hepatopancreas showed opposite tendency. High salinity stress caused a difference in the gill histological structure, the gill structure shrunk, the gill lamellas space and shrinking degree showed an enlarging trend with salinity treatment time.

animal behavior and cognition↗

bioRxiv2021

Large-scale miRNA-Target Data Analysis to Discover miRNA Co-regulation Network of Abiotic Stress Tolerance in Soybeans

Although growing evidence shows that microRNA (miRNA) regulates plant growth and development, miRNA regulatory networks in plants are not well understood. Current experimental studies cannot characterize miRNA regulatory networks on a large scale. This information gap provides a good opportunity to employ computational methods for global analysis and to generate useful models and hypotheses. To address this opportunity, we collected miRNA-target interactions (MTIs) and used MTIs from Arabidopsis thaliana and Medicago truncatula to predict homologous MTIs in soybeans, resulting in 80,235 soybean MTIs in total. A multi-level iterative bi-clustering method was developed to identify 483 soybean miRNA-target regulatory modules (MTRMs). Furthermore, we collected soybean miRNA expression data and corresponding gene expression data in response to abiotic stresses. By clustering these data, 37 MTRMs related to abiotic stresses were identified including stress-specific MTRMs and shared MTRMs. These MTRMs have gene ontology (GO) enrichment in resistance response, iron transport, positive growth regulation, etc. Our study predicts soybean miRNA-target regulatory modules with high confidence under different stresses, constructs miRNA-GO regulatory networks for MTRMs under different stresses and provides miRNA targeting hypotheses for experimental study. The method can be applied to other biological processes and other plants to elucidate miRNA co-regulation mechanisms.

plant biology↗

bioRxiv2021

Deep Transfer Learning of Drug Sensitivity by Integrating Bulk and Single-cell RNA-seq data

Massively bulk RNA sequencing databases incorporating drug screening have opened up an avenue to inform the optimal clinical application of cancer drugs. Meanwhile, the growing single-cell RNA sequencing (scRNA-seq) data contributes to improving therapeutic effectiveness by studying the heterogeneity of drug responses for cancer cell subpopulations. There is a clear significance in developing computational biology approaches to predict and interpret cancer drug response in single cell data from clinical samples. Here, we introduce scDEAL, a deep transfer learning framework for cancer drug response prediction at single-cell level by integrating large-scale bulk cell line data. The true innovation of scDEAL is to translate cancer cell line drug responses into predicting clinical drug responses via learning relations of gene expressions and drug responses at bulk-level and transfer to predict drug responses in scRNA-seq. Another innovation is the integrated gradient feature interpretation to infer a comprehensive set of signature genes to reveal potential drug resistance mechanisms. We benchmarked scDEAL on six scRNA-seq datasets and indicate its model interpretability through these case studies. We believe that this work may help study cell reprogramming, drug selection, and repurposing for improving therapeutic efficacy.

bioinformatics↗