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Mei, Z.

Publications and source records attributed to Mei, Z..

10 recordsLinked to original sources

NeuroCDS: Integrating Local and Global Neural Network Representations via Structural Constrained Viterbi Decoding for Robust CDS Annotation

MotivationRobust annotation of Coding Sequences (CDS) is critical for downstream transcriptomics, yet heavily fragmented de novo RNA-Seq assemblies pose a severe challenge. Traditional computational tools rely on fixed, hand-crafted features that are prone to fail when canonical sequence signals are truncated. While recent deep learning models excel at automatically extracting complex representations, they predominantly treat these as isolated prediction tasks. Lacking a joint inference mechanism to enforce structural constraints, existing models occasionally output biologically invalid predictions. Therefore, a computational framework capable of fusing heterogeneous neural network representations for joint annotation is critically needed. ResultsWe present NeuroCDS, a reliable framework that bridges the effective representation capabilities of deep neural networks with the structural rigor of dynamic programming. NeuroCDS employs a dual-branch architecture: a Convolutional Neural Network (CNN) acts as a local sensor to extract Translation Initiation Sites (TIS), while a Temporal Convolutional Network (TCN) acts as a global sensor to evaluate continuous regional coding potential. The primary contribution of NeuroCDS lies in a structurally constrained Viterbi Decoding algorithm designed to fuse these heterogeneous signals. This joint inference mechanism strictly enforces biological grammars (e.g., reading frame preservation) to dynamically calculate the globally optimal transcript structure via a tripartite state space. Crucially, by introducing a dynamic length normalization mechanism, our formulation adaptively leverages global continuous representations to stably annotate both intact transcripts and highly truncated fragments. Comprehensive evaluations demonstrate that NeuroCDS achieves high F1-scores on full-length transcripts and maintains robust performance on complex Ribo-seq validated datasets, comparing favorably against traditional HMM-based and heuristic methodologies. AvailabilitySource code, pre-trained models, and datasets are freely available at https://github.com/hgcwei/NeuroCDS.

bioinformatics↗

CsFDL1-CsFTL3 complex represses CsFTL3 via negative feedback to fine-tune flowering in Chrysanthemum seticuspe

In many flowering plants, the transition from vegetative growth to reproductive development is regulated by seasonal changes in photoperiod. Under inductive photoperiods, leaves produce the florigen FT (FLOWERING LOCUS T), which is transported to the shoot apex to promote flowering. The photoperiod is known to have a major effect on the flowering of chrysanthemum. In the perennial short-day (SD) plant Chrysanthemum seticuspe, the expression of CsFTL3 (FT-like gene) does not increase immediately after shifting from long-day (LD) to SD conditions but gradually accumulates under continuous SD conditions, peaking during inflorescence development. However, the underlying mechanism remains elusive. We show that CsFDL1 (an ortholog of FD) and CsFTL3 exhibit a significant inverse expression pattern in leaves during the initial stage of short-day inductions. Furthermore, the expression of CsFTL3 is upregulated in the leaves of CsFDL1-knockdown transgenic lines. CsFDL1 is expressed in leaves and forms a complex with CsFTL3 to recognize several TCGA- and ACGT-containing motifs in the CsFTL3 promoter. The CsFTL3-CsFDL1 complex downregulates CsFTL3 expression, thereby preventing its excessive induction by SD signals and inhibiting precocious floral transition. This study reveals that CsFDL1 acts as a key early repressor in the photoperiodic flowering pathway of chrysanthemum leaf, mediating negative feedback regulation by forming a complex with CsFTL3 to achieve precise temporal control of short-day-dependent flowering responses.

plant biology↗

Quantifying Metagenomic Strain Associations fromMicrobiomes with Anpan

Genetic and genomic variation among microbial strains can dramatically influence their phenotypes and environmental impact, including on human health. However, inferential methods for quantifying these differences have been lacking. Strain-level metagenomic profiling data has several features that make traditional statistical methods challenging to use, including high dimensionality, extreme variation among samples, and complex phylogenetic relatedness. We present Anpan, a set of quantitative methods addressing three key challenges in microbiome strain epidemiology. First, adaptive filtering designed to interrogate microbial strain gene carriage is combined with linear models to identify strain-specific genetic elements associated with host health outcomes and other phenotypes. Second, phylogenetic generalized linear mixed models are used to characterize the association of sub-species lineages with such phenotypes. Finally, random effects models are used to identify pathways more likely to be retained or lost by outcome-associated strains. We validated our methods by simulation, showing that we achieve more accurate effect size estimation and a lower false positive rate compared to alternative methodologies. We then applied our methods to a dataset of 1,262 colorectal cancer patients, identifying functionally adaptive genes and strong phylogenetic effects associated with CRC status, sometimes complementing and sometimes extending known species-level microbiome CRC biomarkers. Anpans methods have been implemented as a publicly available R library to support microbial community strain and genetic epidemiology in a variety of contexts, environments, and phenotypes.

bioinformatics↗

Chromosome-scale genome assembly of Tinospora sagittata (Oliv.) Gagnep. enhances identifying genes involved in the biosynthesis of jatrorrhizine

Tinospora sagittata (Oliv.) Gagnep. is an important medicinal tetraploid plant in the Menispermaceae family. Its tuber, namely "Radix Tinosporae" used in Traditional Chinese Medicine, is rich in medicinal terpenoids and benzylisoquinoline alkaloids (BIAs), To enhance understanding the biosynthesis of medicinal compounds, we, herein, report the assembly of a high quality chromosome-scale genome with both PacBio HiFi and Illumina sequencing technologies. The size of assembled genome was 2.33 Gb consisting of 4070 scaffolds (N50=42.06Mb), of which 92.05% were assigned to 26 pseudochromosomes in A and B sub-genomes. A phylogenetic analysis with the T. sagittata and other 16 plant genomes estimated the evolutionary placement of T. sagittata and its divergence time in Ranunculales. Further genome evolution analysis characterized one round tandem duplication about 1.5 million years ago (MYA) and one whole-genome duplication (WGD) about 86.9 MYA. WGD contributed to the duplication of clade-specific cytochrome P450 gene family in Ranunculales. Moreover, sequencing mining obtained genome-wide genes involved in the biosynthesis of alkaloids and terpenoids. TsA02G014550, one candidate, was functionally characterized to catalyze the formation of (S)-canadine in the jatrorrhizine biosynthetic pathway. Taken together, the assembled genome of T. sagittata provides useful sequences to understand the biosynthesis of jatrorrhizine and other BIAs in plants.

genomics↗

Multiomics reveals the genomic, proteomic and metabolic influences of histidyl dipeptides on heart

Histidyl dipeptides, are synthesized in the heart via enzyme carnosine synthase (Carns), which facilitates glycolysis and glucose oxidation by proton buffering and attenuate ischemia and reperfusion injury. However, a composite understanding of the histidyl dipeptide mediated responses in the heart are lacking. We performed multilayer omics in the cardio specific Carns overexpressing mice, showing higher myocardial levels of histidyl dipeptides lead to extensive changes in microRNAs that could target the expression of contractile proteins and enzymes involved in {beta}-fatty acid oxidation and citric acid cycle (TCA). Similarly, global proteomics showed contractile function, fatty acid degradation and TCA cycle, pathways were enriched in the CarnsTg heart. Parallel with these changes, free fatty acids, and TCA intermediate-succinic acid were lower under aerobic and significantly attenuated under anaerobic conditions in the CarnsTg heart. Integration of multiomics data shows {beta}-fatty acid oxidation and TCA cycle exhibit correlative changes at all three levels in CarnsTg heart, suggesting histidyl dipeptides are critical regulators of myocardial structure, function and energetics.

systems biology↗

Significant expression of FURIN and ACE2 on oral epithelial cells may facilitate the efficiency of 2019-nCov entry

Background Leading to a sustained epidemic spread with >40,000 confirmed human infections, including >10,000 deaths, COVID-19 was caused by 2019-nCov and resulted in acute respiratory distress syndrome (ARDS) and sepsis, which brought more challenges to the patient’s treatment. The S-glycoprotein, which recognized as the key factor for the entry of 2019-nCov into the cell, contains two functional domains: an ACE2 receptor binding domain and a second domain necessary for fusion of the coronavirus and cell membranes. FURIN activity, exposes the binding and fusion domains, is essential for the zoonotic transmission of 2019-nCov. Moreover, it has been reported that ACE2 is likely to be the receptor for 2019-nCoV. In addition, FURIN enzyme and ACE2 receptor were expressed in airway epithelia, cardiac tissue, and enteric canals, which considered as the potential target organ of the virus. However, report about the expression of FURIN and ACE2 in oral tissues was limited.Methods In order to investigate the potential infective channel of new coronavirus in oral cavity, we analyze the expression of ACE2 and FURIN that mediate the new coronavirus entry into host cells in oral mucosa using the public single-cell sequence datasets. Furthermore, immunohistochemical staining experiment was performed to confirm the expression of ACE2 and FURIN in the protein level.Results The bioinformatics results indicated the differential expression of ACE2 and FURIN on epithelial cells of different oral mucosal tissues and the proportion of FURIN-positive cells was obviously higher than that of ACE2-positive cells. IHC experiments revealed that both the ACE2-positive and FURIN-positive cells in the target tissues were mainly positioned in the epithelial layers, partly expressed in fibroblasts, which further confirm the bioinformatics results.Conclusions Based on these findings, we speculated that 2019-nCov could effectively invade oral mucosal cells though two possible routes: binding to the ACE2 receptor and fusion with cell membrane activated by FURIN protease. Our results indicated that oral mucosa tissues are susceptible to 2019-nCov, which provides valuable information for virus-prevention strategy in clinical care as well as daily life.Competing Interest StatementThe authors have declared no competing interest.View Full Text

pathology↗

Generation and quality control of maternal plasma lipidomics data associated with preterm birth

Preterm birth is not only one of the most common causes of infant deaths but also a great risk for them to have severe subsequent health problems. The causes of preterm birth may be due to a combination of genetic and environmental factors, however, it remains largely unknown. Here we report an untargeted lipidomics dataset of plasma specimens from 258 pregnant women at the stage of twelve to twenty-five gestational weeks. Among them, 44 had extremely to very preterm births, 54 had moderate preterm births, 71 had late preterm births and 89 had full-term deliveries. The metabolomic profiling was generated with an UPLC-MS in both the positive and negative mode, and putative identification of all the metabolites was provided by searching against online databases. The quality assessment performed on quality control samples showed that the data is reproducible, robust and reliable. Both the raw data files, the raw and processed data matrix were available on MetaboLights, which may be used as a valuable validation dataset for new findings and a test dataset for novel algorithms.

systems biology↗

Reliable Multiplex Sequencing with Rare Index Mis-Assignment on DNB-Based NGS Platform

BackgroundMassively-parallel-sequencing, coupled with sample multiplexing, has made genetic tests broadly affordable. However, intractable index mis-assignments (commonly exceeds 1%) were repeatedly reported on some widely used sequencing platforms.\n\nResultsHere, we investigated this quality issue on BGI sequencers using three library preparation methods: whole genome sequencing (WGS) with PCR, PCR-free WGS, and two-step targeted PCR. BGIs sequencers utilize a unique DNB technology which uses rolling circle replication for DNA-nanoball preparation; this linear amplification is PCR free and can avoid error accumulation. We demonstrated that single index mis-assignment from free indexed oligos occurs at a rate of one in 36 million reads, suggesting virtually no index hopping during DNB creation and arraying. Furthermore, the DNB-based NGS libraries have achieved an unprecedentedly low sample-to-sample mis-assignment rate of 0.0001% to 0.0004% under recommended procedures.\n\nConclusionsSingle indexing with DNB technology provides a simple but effective method for sensitive genetic assays with large sample numbers.

genomics↗

A mouse model of necrotic biliary pancreatitis induced by combining gallstone formation and ligation of the biliary-pancreatic duct

ObjectiveThe aim of the present investigation is to develop a mouse model of biliary pancreatitis with characteristics of both gallstone formation and pancreatitis, mimicking the human etiology and pathphysiological character.\n\nDesignMale C57BL/6 mice were fed with chow, high fat/cholesterol and lithogenic diet for 12 weeks respectively. Laparotomy was done followed by ligation of pancreatic duct (PD), bile duct and pancreatic duct (BPD), or sham operation.\n\nResultsLittle or no evidence of pancreatitis was observed in PD group of mice fed with chow or high fat/cholesterol diet, or in the tail of pancreata removed from animals fed with lithogenic diet. In the head of pancreas, pancreas damage was dramatically more severe in the lithogenic group. When bile reflux was blocked by BPD, pancreas damage markedly reduced to level of chow diet group. The lithogenic diet group also developed significantly more severe multi organ dysfunction syndrome (MODS) in the lung, kidney and liver. The severity of pancreatitis is associated with persistent high bile level of cholesterol and bile acid after obstruction of the biliary-pancreatic duct. Cholesterol crystal aggravated injury of pancreatic acinar cells caused by taurocholate. After obstruction of the biliary-pancreatic duct, in the lithogenic diet group, liver Abcg8 and Cyp7a1 was up-regulated, compared to the control group.\n\nConclusionWe developed a mouse model of severe biliary pancreatitis in both local pancreas damage and MODS. This model provides a sound explanation for the Opie theory dilemma and a potential therapeutical direction in clinical practice as well.\n\nSummary statementA biliary pancreatitis has characters of both gallstone and pancreatitis, mimicking human etiology and pathophysiology, which gave a clear answer to the long time Opie theory dilemma.

pathology↗

Genetic footprint of population fragmentation and contemporary collapse in a freshwater cetacean

Understanding demographic trends and patterns of gene flow in an endangered species is crucial for devising conservation strategies. Here, we examined the extent of population structure and recent evolution of the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis). By analysing genetic variation at the mitochondrial and nuclear microsatellite loci for 148 individuals, we identified three populations along the Yangtze River, each one connected to a group of admixed ancestry. Each population displayed extremely low genetic diversity, consistent with extremely small effective size ([≤]92 individuals). Habitat degradation and distribution gaps correlated with highly asymmetric gene-flow that was inefficient in maintaining connectivity between populations. Genetic inferences of historical demography revealed that the populations in the Yangtze descended from a small number of founders colonizing the river from the sea during the last Ice Age. The colonization was followed by a rapid population split during the last millennium predating the Chinese Modern Economy Development. However, genetic diversity showed a clear footprint of population contraction over the last 50 years leaving only ~2% of the pre-collapsed size, consistent with the population collapses reported from field studies. This genetic perspective provides background information for devising mitigation strategies to prevent this species from extinction.

evolutionary biology↗