Biomedical subjects

Dan Zhu

Publications and source records attributed to Dan Zhu.

3 recordsLinked to original sources

PubMed2026

PtoeIF5A1: A Pleiotropic Regulator of Development, PCD, and Salt Tolerance in Populus tomentosa.

Eukaryotic translation initiation factor 5A (eIF5A) is a highly conserved protein family unique to eukaryotes, yet its functional characterization in woody plants remains limited. In this study, we identified four eIF5A genes (PtoeIF5A1-PtoeIF5A4) from the genome of Populus tomentosa, a fast-growing tree species indigenous to China, and characterized their expression patterns and functional roles through bioinformatics analysis, quantitative real-time PCR, stable overexpression in Arabidopsis thaliana, and transient expression in Nicotiana benthamiana leaves. Our results demonstrated that all PtoeIF5A proteins contain a conserved OB-fold domain and multiple phosphorylation sites, with PtoeIF5A1 showing predominant expression in roots and secondary xylem. Functional assays revealed that PtoeIF5A1 overexpression accelerated inflorescence stem elongation and early flowering in Arabidopsis, induced visible chlorosis and programmed cell death (PCD) in tobacco leaves, and significantly enhanced salt tolerance under NaCl treatment. Collectively, these findings establish PtoeIF5A1 in poplar as a pleiotropic regulator integrating developmental cues, programmed cell death, and stress responses; and as a valuable genetic resource for breeding stress-resilient woody plants.

Populus tomentosa↗

PubMed2026

Chemotactic sensing of extracellular antibiotic resistance genes enables their efficient removal by Stutzerimonas stutzeri.

The dissemination of antibiotic resistance genes (ARGs) in wastewater environments poses a severe threat to public health. Extracellular ARGs (eARGs) persist as free DNA fragments that are refractory to efficient removal by conventional physicochemical treatment technologies. Here, we isolated Stutzerimonas stutzeri CHY07 from municipal sewage and demonstrated that extracellular DNA fragments, including eARGs, can serve as chemoattractants for environmental bacteria. Through genomic mining, molecular docking, surface plasmon resonance (SPR), isothermal titration calorimetry (ITC) and protein-ligand interaction profiling, we identified the chemoreceptor Mcp16 as the primary sensor of extracellular DNA and revealed that it achieves sequence-independent recognition of the DNA phosphate backbone. We further established the endogenous pentapeptide VRSVR as a methylation substrate for CheR and constructed the engineered strain CHY07-2 (mcp16::VRSVR) using an SSB/CRISPR-Cas9 ribonucleoprotein (RNP) system. This strain exhibited significantly enhanced chemotactic responsiveness, achieving 72-h removal efficiencies of 96.56% and 91.60% for low- and high-molecular-weight eARGs in non-sterile WWTP secondary effluent; conversely, mcp16 deletion markedly attenuated both chemotaxis and removal, whereas in situ complementation restored them. These findings reveal a "chemotaxis-contact-removal" cascade - with a proposed self-reinforcing loop - in eARG-removing bacteria, providing both a theoretical framework and a technical paradigm for enhancing pollutant removal through targeted amplification of microbial chemotaxis.

Chemotaxis↗

PubMed2025

Unraveling the molecular choreography of C3 to CAM transition in Mesembryanthemum crystallinum using phosphoproteomics.

Climate change and population growth threaten global freshwater resources and food security. Crassulacean acid metabolism (CAM) is a specialized photosynthetic adaptation that exhibits superior water use efficiency (WUE) compared to C3 and C4 photosynthesis. Mesembryanthemum crystallinum (common ice plant) is capable of shifting from C3 to CAM, making it a key model for investigating photosynthesis plasticity and its potential to enhance crop stress resilience. To date, the molecular mechanisms underlying this high-WUE photosynthetic transition remain largely unknown. Using mass spectrometry-based proteomics and phosphoproteomics, we quantified 4233 phosphopeptides containing 4758 phosphorylation sites, including the well-characterized Serine 11 of phosphoenolpyruvate carboxylase 1 (PEPC1). It is a critical phosphorylation site facilitating nocturnal CO2 fixation during CAM. Our analysis revealed many phosphorylation sites that exhibited similar diel patterns as the PEPC1 pS11, and they may be part of the regulatory network involved in CAM induction. Glycolysis/gluconeogenesis and carbon storage/breakdown modules exhibited extensive phosphorylation regulation, and vesicle trafficking could play a role in nocturnal carbon fixation. Furthermore, glycine-rich RNA-binding protein 7 (GRP7) in association with cold shock protein 1 (CSP1) emerged as a potential transcriptional switch for nocturnal stomatal opening. On the other hand, ABI5-binding protein 1 (AFP1) and oxidative stress 3 (OXS3)-activated ABA signaling, along with high CO2 signaling and suppressed blue light signaling, may contribute to diurnal stomatal closure. These findings shed light on the protein phosphorylation changes and provide valuable targets for functional characterization of their roles in CAM induction.

Mesembryanthemum↗