Biomedical subjects

Qinghua Zhang

Publications and source records attributed to Qinghua Zhang.

4 recordsLinked to original sources

PubMed2026

Nitrilase-mediated degradation of insecticides flonicamid and thiacloprid by immobilized engineered Escherichia coli with a novel pathway.

The nitrile‑containing insecticides flonicamid (FLO) and thiacloprid (THI) are widely used in agriculture, posing risks to the environment and animal health. Nitrilase is a key catalyst for the degradation of nitrile compounds, and immobilized engineered bacteria are preferred in wastewater treatment. However, immobilized engineered bacteria expressing nitrilase have never been investigated for pollutant degradation. Here, engineered Escherichia coli pET28a‑VbNitA harboring the nitrilase gene VbNitA was immobilized by calcium alginate encapsulation. FLO was degraded into N-(4-trifluoromethylnicotinoyl)glycinamide and 4-(trifluoromethyl)nicotinol glycine by the immobilized cells via VbNitA. THI was converted to THI‑amide and THI‑imine using the same system. Notably, this is the first report of a nitrilase converting THI to THI‑amide and of THI‑imine as a biodegradation intermediate. Compared with free cells, the immobilized E. coli pET28a‑VbNitA showed higher tolerance to high temperature, alkaline, and acidic environments, and better long-term storage stability. The substrate inhibition model showed that the optimal initial concentrations of FLO and THI for degradation by immobilized E. coli pET28a‑VbNitA were 45.13 and 127.50 μmol/L, respectively. FLO was degraded more rapidly than THI by the immobilized cells. Molecular docking revealed that both FLO and THI formed stable interactions with VbNitA, with FLO positioned closer to Cys165 of the catalytic triad. This study presents a novel THI degradation pathway and provides a new, efficient immobilized biocatalyst for the remediation of wastewater with nitrile‑containing insecticides.

Escherichia coli↗

PubMed2026

Identification of novel HUWE1 variants in Turner-type X-linked intellectual disability.

OBJECTIVE: To characterize the clinical phenotypes and identify the genetic etiology in four unrelated families affected by Turner-type X-linked intellectual disability (XLID). METHODS: Peripheral blood samples were collected from four probands and their parents. Genomic DNA was extracted, and a comprehensive genetic analysis was performed using trio-based Whole Exome Sequencing (WES) combined with low-pass Copy Number Variation sequencing (CNV-seq). Candidate variants were subsequently validated via Sanger sequencing. RESULTS: Genetic analysis identified distinct variants in the HUWE1 across the four families. Specifically, four distinct HUWE1 variants were identified across the families: a hemizygous c.10034 > T (p.Lys3345Met) in Family 1; a heterozygous c.9209G > A (p.Arg3070His) in Family 2; a heterozygous c.12688T > C (p.Phe4230Leu) in Family 3; and a hemizygous c.9070G > A (p.Ala3024Thr) in Family 4. In accordance with ACMG guidelines, the novel variants in Families 1, 3, and 4 were classified as "Likely Pathogenic" (PS2 + PM2_Supporting + PP2 + PP3). In contrast, the previously reported variant in Family 2 was categorized as "Pathogenic" based on the criteria PS2 + PM2_Supporting + PM5 + PP2 + PP3_Moderate. All probands were clinically diagnosed with Turner-type XLID. CONCLUSIONS: This study expands the pathogenic variant spectrum of HUWE1 and provides novel molecular evidence for the clinical diagnosis of Turner-type XLID. These findings are of significant value for genetic counseling, carrier screening, and prenatal diagnosis for the affected families.

Humans↗

PubMed2025

Characterization of non-crossover recombination spectrum by single-microspore sequencing in maize and rice.

Meiotic DNA double-strand breaks (DSB) are crucial for chromosome recombination. The repair of DSB gives two outcomes: crossover (CO) and non-crossover (NCO). CO involves the bidirectional exchange between homologous chromosomes, whereas NCO refers to the unidirectional transfer of chromosome fragments. NCO can be categorized into NCO with gene conversion and NCO without gene conversion. Due to technological constraints, previous studies have focused more on CO than on NCO. In this study, we isolated single microspores from meiotic tetrads of maize (Zea mays) and rice (Oryza sativa) and conducted deep single-microspore genome sequencing to characterize NCO gene conversion (NCO-GC). Under highly stringent conditions, 101 CO and 902 NCO-GC tracts were identified in four maize tetrads, while 173 CO and 279 NCO-GC tracts were identified in six rice tetrads. In both maize and rice, NCO-GC was more prone to occur in the upstream and downstream of genes, as well as the introns. It also had a significant distribution in transposon regions. A common A-rich motif was enriched in the NCO-GC tracts of maize and rice. GC-biased gene conversion (gBGC) likely contributed to the bimodality of the GC content at the third codon position (GC3), and we discovered a significant proportional relationship between the number of DSBs and the GC content. These findings provide evidence that NCO-GC exhibits a distinct pattern compared with CO and may play an important role in gene and genome evolution.

Oryza↗

PubMed2024

Metagenomic insights into ecological risk of antibiotic resistome and mobilome in riverine plastisphere under impact of urbanization.

Microplastics (MPs) are of increasing concern due to their role as reservoirs for antibiotic resistance genes (ARGs) and pathogens. To date, few studies have explored the influence of anthropogenic activities on ARGs and mobile genetic elements (MGEs) within various riverine MPs, in comparison to their natural counterparts. Here an in-situ incubation was conducted along heavily anthropogenically-impacted Houxi River to characterize the geographical pattern of antibiotic resistome, mobilome and pathogens inhabiting MPs- and leaf-biofilms. The metagenomics result showed a clear urbanization-driven profile in the distribution of ARGs, MGEs and pathogens, with their abundances sharply increasing 4.77 to 19.90 times from sparsely to densely populated regions. The significant correlation between human fecal marker crAssphage and ARG (R2 = 0.67, P=0.003) indicated the influence of anthropogenic activity on ARG proliferation in plastisphere and natural leaf surfaces. And mantel tests and random forest analysis revealed the impact of 17 socio-environmental factors, e.g., population density, antibiotic concentrations, and pore volume of materials, on the dissemination of ARGs. Partial least squares-path modeling further unveiled that intensifying human activities not only directly boosted ARGs abundance but also exerted a comparable indirect impact on ARGs propagation. Furthermore, the polyvinylchloride plastisphere created a pathogen-friendly habitat, harboring higher abundances of ARGs and MGEs, while polylactic acid are not likely to serve as vectors for pathogens in river, with a lower resistome risk score than that in leaf-biofilms. This study highlights the diverse ecological risks associated with the dissemination of ARGs and pathogens in varied MPs, offering insights for the policymaking of usage and control of plastics within urbanization.

Urbanization↗