PubMed Health⌕ Search

Biomedical subjects

Lijun Wang

Publications and source records attributed to Lijun Wang.

3 recordsLinked to original sources
PubMed2026

Hypervirulence-associated pseudo-compound transposons as fundamental mobile units driving cross-species virulence dissemination in Enterobacteriaceae.

BACKGROUND: The rapid global spread of hypervirulence in Enterobacteriaceae, particularly in carbapenem-resistant Klebsiella pneumoniae, poses a significant public health threat. However, the key genetic vehicles and mechanisms driving horizontal transfer of hypervirulence-associated genes (iucA, iroB, rmpA, rmpA2, and peg-344) remain poorly defined, limiting effective surveillance. METHODS: We performed a large-scale genomic survey of 2,869 virulence-associated plasmid sequences and 2,337 complete Enterobacteriaceae chromosomes. Using comparative genomics and evolutionary analyses, we systematically identified and characterized Hypervirulence-associated Pseudo-Compound Transposons (Hva-PCTs), defined as structured mobile elements in which hypervirulence-associated genes are flanked by insertion sequences. RESULTS: Our results demonstrate that hypervirulence-associated genes are transmitted primarily as discrete IS-bounded units, which we term Hva-PCTs. We identified 29 distinct plasmid-borne Hva-PCTs (pHva-PCTs) and 30 chromosomal Hva-PCTs (cHva-PCTs). These modules show clear species-specific patterns: iucA/iroB-associated Hva-PCTs mainly originate in Escherichia coli and spread through IncFIB-containing multi-replicon plasmids (commonly combined with IncFIC(FII) and/or IncFII, while rmpA/rmpA2/peg-344-containing modules originate in K. pneumoniae and are disseminated via IncHI1B/repB plasmids. Three Hva-PCTs were detected on both plasmids and chromosomes (xHva-PCTs). In one clinical K. pneumoniae isolate (LS356), the identical composite module was present on both replicons. Simpler sub-modules, such as ISKqu3-rmpA2-iucA_1-IS102 and IS102-rmpA-peg-344-iroB_1-IS1A, frequently co-occur on the same plasmid; when positioned in tandem, they reconstitute the full composite structure. This assembly pattern is further supported by a partial duplication event in plasmid pP901. CD-HIT clustering (80% nucleotide identity and 90% coverage) showed that 13 of 22 major clusters contained both plasmid and chromosomal copies, with intra-cluster identities >80% across multiple sequence types and host species. CONCLUSION: Hypervirulence-associated genes in Enterobacteriaceae are disseminated mainly as IS-flanked Hva-PCTs rather than solely through intact virulence plasmids. These modules exhibit strong but not absolute host specificity. The presence of identical Hva-PCTs on plasmids and chromosomes suggests inter-replicon mobility, while their stepwise assembly from simpler sub-modules highlights modular accretion as a key evolutionary process. Tracking Hva-PCTs as distinct mobile units may complement existing plasmid- and gene-centric surveillance approaches for hypervirulent and convergent strains. Experimental validation of their transposition activity and phenotypic effects is still required.

Virulence↗
PubMed2026

Study of the densification mechanisms of Al-Fe-Cr-Ti alloys during high-velocity compaction based on 3D MPFEM.

Aluminum alloy materials are widely used in aerospace and related fields, among which Al-Fe-Cr-Ti alloys have attracted increasing attention owing to their low density and excellent comprehensive properties. However, the densification mechanisms of alloy powders during high-velocity compaction (HVC) remain insufficiently understood. In this study, a three-dimensional multi-particle finite element method (3D MPFEM) model was developed to simulate the HVC process of Al-Fe-Cr-Ti alloy powders and to evaluate the effects of friction coefficient μ, impact energy per unit mass Em, hammer mass M, and compaction velocity v on powder densification. The results show that increasing μ from 0.25 to 0.65 reduced kinetic-energy transfer and stress transmission, decreasing the relative density ρ of the green from 0.7076 to 0.6797. In contrast, increasing Em from 55.58 to 144.67 J/g markedly improved densification, with the maximum relative density reaching 0.8881. Displacement-field analysis further revealed that appropriate combinations of M and v promote particle rearrangement and plastic deformation. Experimental validation confirmed that the simulated density evolution agreed well with the measured trend, although the predicted values were slightly lower. These findings indicate that 3D MPFEM can reasonably describe the macroscopic densification trend and provide qualitative particle-scale insights into deformation and energy-transfer behavior during HVC.

3D MPFEM↗
PubMed2025

Chromosome-level genome assembly of Cheilinus chlorourus (Bloch, 1791) (Perciformes: Labridae).

In the classification of marine fish, the Labridae family ranks second in terms of species diversity and plays a vital role in coral reef ecosystems, comprising over 600 species across 82 genera. Despite its significance for ecological and evolutionary studies, genomic research on this group has lagged, resulting in a shortage of data, particularly regarding high-quality chromosome-level genome assemblies. To address this gap, this study focused on Cheilinus chlorourus from the Labridae family and successfully achieved a chromosome-level genome assembly. By integrating Illumina, PacBio, and Hi-C sequencing data, we assembled a genome measuring 940.36 Mb, with 926.86 Mb (98.56%) of the gene assembly organized into 21 chromosomes. A total of 29,213 protein-coding genes (PCGs) were identified, and 79.93% of these genes were functionally annotated. With this high-quality genome assembly, future investigations into the functional genomics and ecology of C. chlorourus will have a solid scientific foundation.

Animals↗