Biomedical subjects

Quan Wang

Publications and source records attributed to Quan Wang.

At least 19 recordsLinked to original sources

PubMed2026

Auxin-induced ARF transcription factor degradation defines tissue boundaries.

How organs partition themselves into discrete domains with distinct functions is a fundamental question in biology. The gynoecium of flowering plants provides an excellent system to address this question. Here, we show that the boundary between the stigma and style at the gynoecium apex is established by the complementary distribution of the phytohormone auxin and the Auxin Response Factor (ARF), ETTIN (ETT). Mechanistically, auxin induces ETT protein destabilization via the ubiquitin-proteasome pathway. A short sequence motif within an intrinsically disordered region is required for this auxin-triggered degradation. Disruption of this motif leads to ectopic ETT accumulation at the gynoecium apex and consequently abolishes stigma-style boundary development. We further demonstrate that this previously unrecognized mode of auxin-induced ARF instability is evolutionarily conserved among ETT orthologs across angiosperms. In summary, this study reveals how graded auxin distribution affects ARF transcription factor activity, contributing to the establishment of the stigma-style boundary, ensuring correct gynoecium formation and reproductive success in flowering plants.

Indoleacetic Acids↗

PubMed2026

From Static to Dynamic: Fluorescence Imaging Technology Advances Precise Embryo Evaluation.

Live-cell imaging technology has revolutionized our understanding of preimplantation embryonic development, shifting the field from static morphological descriptions to dynamic functional analyses. This has tremendously advanced the fields of in vitro fertilization (IVF) and embryonic development. At the heart of this transition lies the strategic application of fluorescent probes, which provide the requisite sensitivity and specificity to resolve complex biological events. This review provides a comprehensive overview of fluorescent probe-based strategies designed to address four cardinal questions in peri-implantation embryology: genomic stability, cell fate determination, tissue morphogenesis, and embryo-maternal interactions. We systematically evaluate the chemical design principles and imaging modalities of various probes, which range from small-molecule organic fluorophores to genetically encoded reporters and nanoparticle-based sensors. Furthermore, we discuss how these tools facilitate the real-time visualization of chromosomal aberrations, lineage segregation, biomechanical forces, and enzymatic activities within the delicate embryonic microenvironment. This review summarizes methodological strategies for selecting and developing optimal probes across diverse application contexts. By identifying current technical bottlenecks and proposing future directions, such as NIR-II imaging and noninvasive labeling, it aims to drive the translation of basic embryonic research into advanced reproductive medicine.

Humans↗

PubMed2026

The Incidence of Suicide Following Metabolic and Bariatric Surgery: A Prognosis Systematic Review and Meta-Analysis of Longitudinal Studies.

BACKGROUND: Metabolic and bariatric surgery (MBS) effectively manages severe obesity but may lead to psychological complications such as completed suicides and suicide attempts. This review aimed to analyze suicide and self-harm incidence post-MBS. METHODS: We searched MEDLINE, EMBASE, PsycINFO, and the Cochrane Library databases on August 16, 2022, for longitudinal studies with incidence data on suicide following MBS. We performed a single proportion meta-analysis on the incidence of outcomes and assessed the certainty of evidence using the GRADE approach. The review was registered with PROSPERO (CRD42022352137). RESULTS: Eighty-four studies were included. The meta-analysis showed an incidence of 230.64 suicides per 100,000 participants (95% CI: 167.51 to 317.49) in pooled individual-level data and an incidence of 43.02 suicides per 100,000 person-years (95% CI: 32.49 to 56.97) in pooled person-year data. Evidence was low certainty or very low certainty. CONCLUSIONS: The average suicide incidence (231 per 100,000 people) in people with obesity who underwent MBS significantly exceeded the 2019 WHO global estimate for the general population (nine per 100,000 people). These findings underscore the need to incorporate structured psychological screening and follow-up into the perioperative management process of MBS, as patient mental health may play a pivotal role in postoperative adherence and long-term outcomes.

Humans↗

PubMed2026

Pragmatic Phenotype-Electrophysiology-Genomics Integration in Pediatric Congenital Myasthenic Syndromes: Insights From 36 Patients in a Single-Center Study in China.

AIMS: To characterize the clinical, electrophysiological, and genetic spectrum of pediatric CMS and evaluate genotype-informed outcomes using an integrated phenotype-electrophysiology-genomics approach. METHODS: We retrospectively reviewed 36 pediatric CMS patients evaluated at a single center between 2015 and 2025. Clinical features, RNS, targeted NGS/WES variants, ventilator use, treatments, ACMG/AMP classifications, and MG-ADL outcomes were analyzed. RESULTS: Of 36 patients, 28 (77.8%) developed symptoms in the neonatal period or infancy. Biallelic variants involved 17 CMS genes; postsynaptic CMS was most common (55.6%, 20/36). COLQ and CHRNE were the most frequent genes (13.9%, 5/36 each), followed by CHAT (11.1%, 4/36). VUS were detected in 19 patients (52.8%, 19/36), including 8 with biallelic VUS supported by phenotype, neuromuscular transmission findings, treatment response, and follow-up. RNS showed a ≥ 10% decrement in 16/21 tested patients (76.2%). CHAT-CMS was associated with higher ventilator use (3/4 vs. 6/32; p = 0.041) and early mortality (3/4 vs. 1/32; p = 0.002). Median MG-ADL improved from 5 to 3 after genotype-informed therapy. CONCLUSION: Pediatric CMS shows marked genetic heterogeneity and frequent VUS-related uncertainty. Integrating phenotype, electrophysiology, and genomics supports diagnosis and mechanism-guided therapy. CHAT-CMS is high risk for early respiratory failure and mortality.

Humans↗

PubMed2025

CRISPR-Cas9-mediated knockout of OsKCS11 in rice reveals potential crosstalk between very-long-chain fatty acids and cytokinin.

Very-long-chain fatty acids (VLCFAs) play crucial roles in various physiological processes in plants. Through our investigation using a CRISPR-Cas9 knockout mutant library in rice, we identified a semi-dwarf rice mutant named CRISPR-Cas-based dwarf-1 (csd-1). This mutant displayed multiple developmental defects, such as decreased plant height, panicle length, seed size, and seed-setting rate. Whole-genome resequencing analysis revealed that a T-nucleotide insertion in β-ketoacyl-CoA synthase 11 (KCS11), responsible for the initial step in fatty acid elongation, was responsible for the observed defects in csd-1. The identity of csd-1 was confirmed through genetic complementation and CRISPR-Cas9-mediated knockout. Expression analysis indicated that OsKCS11 was present in various tissues, with differential abundance observed through RT-qPCR and promoter GUS staining, and strong localization at the node position by RNA in situ hybridization; furthermore, OsKCS11 protein was confirmed to be in the endoplasmic reticulum. Furthermore, csd-1 exhibited significantly reduced levels of linolenic acid (18:3), C24:0-OH, C28:0-alkanes, C29:0-alkanes, alpha-tocopherol, and C33:0-alkanes, while trans-nonadecenoic acid and behenic acid levels were increased. Cytokinin analysis revealed significant increases in isopentenyladenine (IPA) and cis-zeatin (cZ) levels in csd-1. Molecular investigations indicated upregulation of genes involved in cytokinin biosynthesis or signaling, suggesting a potential link between VLCFAs and cytokinin synthesis through acetyl-CoA. This study not only proposed an alternative gene mapping method based on whole-genome resequencing but also elucidated the mechanism by which VLCFAs influence cytokinin synthesis and signaling.

Oryza↗

PubMed2007

Protection of mice against homologous or heterologous infections with antiserum mixture to the predominant variable antigen type repertoire of Trypanosoma evansi YNB stock.

The objective of this study was to test a hypothesis that the predominant variable antigen type (VAT) repertoire of a single stock of Trypanosoma evansi was limited and small. It was further assumed that six rabbits could produce all antibodies against the predominant VAT repertoire of a stock of T. evansi and the antiserum mixture from the six rabbits containing all the antibodies could completely protect mice against any homologous stock infections and partially protect mice against some heterologous stock infections. Mice were each intraperitoneally infected with 100 parasites of clone-derived and non-clone-derived populations of the YNB stock, Kazakhstan strain or Vietnam strain of T. evansi, and treated with the antiserum mixture when trypanosomes had been detected in the blood. All of the 10 mice infected with either non-clone-derived or clone-derived populations of the YNB stock survived, and some (4/10) of mice infected with the heterologous Kazakhstan strain survived, while all those (10/10) infected with the heterologous Vietnam strain died. These results support the hypothesis that the predominant VAT repertoire of a single stock of T. evansi was limited and small, and have important implications in the consideration of treating human trypanosomosis due to drug resistant strains with antiserum mixture.

Agglutination Tests↗

PubMed2007

Heat shock stress ameliorates cytokine mixture-induced permeability by downregulating the nitric oxide and signal transducer and activator of transcription pathways in Caco-2 cells.

Proinflammatory cytokines are known to impair intestinal barrier function and to activate signaling pathways, whereas heat shock responses prevent cytokine-induced mucosal damage. We hypothesized that heat shock response blocks the effects of proinflammatory cytokines by regulating nitric oxide (NO) production and the activities of the Janus kinase/signal transducer and activator of transcription (STAT) pathway. A monolayer of Caco-2 cells were pretreated with sodium arsenite (SA, 500 micromol/L) for 1 h, followed by a 1-h recovery, and then stimulated with a cytokine mixture (cytomix: tumor necrosis factor alpha [10 ng/mL], interferon beta [1000 U/mL], and interleukin [IL] 1beta [1 ng/mL]) for 24 h. The permeability of horseradish peroxidase and fluorescein isothiocyanate-conjugated Dextran and transepithelial resistance and potential difference were measured in Ussing chambers. Interleukin-6, IL-8, NO, inducible NO synthase mRNA, STAT activity, and suppressor of cytokine signaling (SOCS) expression were measured in medium or cell lysates. Cytomix resulted in increased epithelial permeability of both fluorescein isothiocyanate-conjugated Dextran and horseradish peroxidase; whereas treatment of Caco-2 cells with SA 500 micromol/L blocked the cytomix-induced permeability changes. In addition, SA treatment decreased cytomix-induced NO production and inducible NO synthase mRNA expression and decreased the levels of STAT1, STAT3, SOCS1, and SOCS3. The SA treatment also decreased cytomix-induced IL-6 and IL-8 production in a dose-dependent manner. In conclusion, cytomix increased epithelial permeability, which is associated with increased NO and STAT activities. The SA treatment ameliorated cytomix-induced permeability, possibly through the downregulation of the NO and Janus kinase/STAT pathways.

Caco-2 Cells↗

PubMed2007

Structural and genetic evidence that the Escherichia coli O148 O antigen is the precursor of the Shigella dysenteriae type 1 O antigen and identification of a glucosyltransferase gene.

Shigella dysenteriae type 1 is the most virulent serotype of Shigella. Enterotoxigenic Escherichia coli O148 is pathogenic and can cause diarrhoea. The following structure was established for the tetrasaccharide repeating unit of the E. coli O148 O antigen: -->3)-alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->2)-alpha-D-Glcp-(1-->3)-alpha-D-GlcpNAc-(1-->. This differs from the structure reported earlier for S. dysenteriae type 1 by having a glucose (Glc) residue in place of a galactose (Gal) residue. The two bacteria also have the same genes for O antigen synthesis, with the same organization and high level of DNA identity, except that in S. dysenteriae type 1 wbbG is interrupted by a deletion, and a galactosyltransferase gene wbbP located on a plasmid is responsible for the transfer of galactose to make a novel antigenic epitope of the O antigen. The S. dysenteriae type 1 O antigen was reconstructed by replacing the E. coli O148 wbbG gene with the wbbP gene, and it had the LPS structure and antigenic properties of S. dysenteriae type 1, indicating that the S. dysenteriae type 1 O antigen evolved from that of E. coli O148. It was also confirmed that wbbG of E. coli O148 is a glucosyltransferase gene, and two serotype-specific genes of E. coli O148 and S. dysenteriae type 1 were identified.

Bacterial Proteins↗

PubMed2006

Characterization of E. coli O24 and O56 O antigen gene clusters reveals a complex evolutionary history of the O24 gene cluster.

O antigen is part of the lipopolysaccharide present in the outer membrane of Gram-negative bacteria. It has many different forms, which are almost entirely due to genetic variations of O antigen gene clusters. In this study, the O antigen gene clusters of E. coli O24 and O56 were sequenced, and all genes were assigned functions on the basis of homology. Comparison of O antigen gene clusters indicated that E. coli O24 O antigen gene cluster has possibly arisen from the E. coli O56 gene cluster, through inactivation of two glycosyltransferase genes and acquisition of two new genes from E. coli O157 and O152, respectively. The insertion sequence elements seemed to play important roles for the assembly of the O24 O antigen gene cluster. This is the first time that the evolutionary history of a multi-origin O antigen gene cluster is clearly demonstrated. Genes specific to E. coli O24 and O56 were also identified, which may be used for development of DNA-based serotyping schemes.

Base Sequence↗

PubMed2006

K-19 mRNA RT-PCR in detecting micrometastasis in regional lymph nodes of gastric cancer.

AIM: To investigate the value and prospect of RT-PCR in detecting micrometastasis in regional lymph nodes of gastric cancer. METHODS: Histopathology was used and K19 mRNA expression was detected by RT-PCR in tumor tissues and lymph nodes from gastric cancer patients undergoing radical resection of gastric carcinoma. RESULTS: K19 mRNA was expressed in all tumor specimens of 30 cases; of the 126 lymph nodes, 26 were histopathologically positive (20.6%), and 42 positive (33.3%) by RT-PCR. Amplification fragments of 460 and 540 bp were shown in all the tumor tissues and metastatic lymph nodes after K19 and beta-actin RT-PCR, while only a 540 bp fragment appeared in the lymph nodes of non-tumor patients. CONCLUSION: K19 mRNA RT-PCR is sensitive and specific in testing micrometastasis in regional lymph nodes of gastric cancer, and it is superior to routine histopathology.

Actins↗

PubMed2006

Structural and genetic characterization of Shigella boydii type 17 O antigen and confirmation of two new genes involved in the synthesis of glucolactilic acid.

Shigella strains are human pathogens and normally identified based on their O antigens. The chemical structure and gene cluster of Shigella boydii type 17 O antigen were studied. As judged by sugar and methylation analyses along with NMR spectroscopy data, the O antigen of S. boydii type 17 has a linear trisaccharide O unit, which consists of two residues of N-acetylgalactosamine (GalNAc) and a 4-O-[(R)-1-carboxyethyl]-d-glucose (glucolactilic acid). The O antigen gene cluster of S. boydii type 17 was sequenced and genes encoding UDP-N-acetylglucosamine C4 epimerase for GalNAc synthesis, O unit flippase, O antigen polymerase, and glycosyltransferases were putatively identified based on sequence similarities and the presence of conserved motifs. Two genes, whose functions could not be clearly indicated by homology search, were confirmed to be involved in the synthesis of glucolactilic acid by mutation and structural verification of the O antigens from the mutants. To our knowledge, this is the first time that genes involved in the synthesis of glucolactilic acid have been reported. Two genes specific to S. boydii type 17 were also identified.

Amino Acid Motifs↗

PubMed2006

Development of a DNA microarray to identify the Streptococcus pneumoniae serotypes contained in the 23-valent pneumococcal polysaccharide vaccine and closely related serotypes.

Streptococcus pneumoniae is a major worldwide human pathogen. This investigation has developed a reliable and accurate DNA microarray method for inter-species differentiation of S. pneumoniae and intra-species differentiation of the 23 groups of S. pneumoniae including serotypes represented in the 23-valent pneumococcal vaccine and the other 20 closely related serotypes. In addition to 16S rDNA probes, serotype- or serogroup-specific probes targeting the capsular polysaccharide synthesis (cps) genes, wzy or capA were generated. We adopted a two-step multiplex PCR to improve the sensitivity of detection to a level of 10(5) cfu/ml in pure culture or 50 ng DNA. A total of 169 isolates (from China, Australia, Canada and New Zealand) including 147 belonging to 23-valent vaccine and closely related serotypes of S. pneumoniae, 11 belonging to other serotypes and 11 of different species commonly isolated from respiratory tract were tested to verify the method. The DNA microarray method developed provides a sensitive means to rapidly identify the members of the most common S. pneumoniae serotypes in patients and to monitor their distribution in different patient groups and geographic locations. Such information is needed for disease surveillance and to monitor vaccine efficacy.

Bacterial Proteins↗

PubMed2006

Structure of a teichoic acid-like O-polysaccharide of Escherichia coli O29.

A teichoic acid-like O-polysaccharide was isolated by mild acid degradation of the lipopolysaccharide (LPS) of Escherichia coli O29. The O-polysaccharide and an oligosaccharide obtained by dephosphorylation of the O-polysaccharide were studied by sugar analysis along with 1H and 13C NMR spectroscopy. The following structure of the branched oligosaccharide repeating unit, containing five monosaccharide residues and glycerol 1-phosphate (D-Gro-1-P), was established: [carbohydrate structure: see text].

Carbohydrate Sequence↗

PubMed2006

Microbial O-demethylation, hydroxylation, sulfation, and ribosylation of a xanthone derivative from Halenia elliptica.

1-Hydroxy-2,3,5-trimethoxyxanthone (1), one of the major xanthone derivatives isolated from Halenia elliptica, was biotransformed by two fungi, Trichothecium roseum and Paecilomyces marquandii. Transformation of 1 by T. roseumgave 1,5-dihydroxy-2,3-dimethoxyxanthone (2), 5-O-sulfate-1-hydroxy-2,3-dimethoxyxanthone (3), 5-O-sulfate-1-hydroxy-2,3,7-trimethoxyxanthone (4), 5-O-beta-ribofuranosyl-1-hydroxy-2,3-dimethoxyxanthone (5), and 1,5,6-trihydroxy-2,3-dimethoxyxanthone (6). Compound 2 was also formed by P. marquandii. The structures of the isolated compounds were elucidated by spectroscopic analyses. Among the five microbial-converted compounds, 3, 4, 5, and 6 are new compounds.

Ascomycota↗

PubMed2006

Use of a serotype-specific DNA microarray for identification of group B Streptococcus (Streptococcus agalactiae).

Group B Streptococcus (GBS; Streptococcus agalactiae) is an important cause of sepsis and meningitis. Nine GBS serotypes, based on capsular polysaccharide (CPS) antigens, have been described. Their distribution varies worldwide and needs to be monitored to understand the epidemiology of GBS disease and inform the development of vaccines. In this study, we sequenced cpsH of GBS serotype II (cpsHII) and compared it with that of the other eight serotypes to identify serotype-specific regions. We then developed a DNA microarray based on the cpsH gene and used it to test 88 GBS isolates-9 serotype reference strains and 79 clinical isolates-and 7 other bacterial and fungal species which are commonly present in the vagina flora. The microarray was shown to be specific and reproducible. This is the first report of a microarray which can identify the nine GBS serotypes. The use of a microarray has advantages over traditional serotyping methods and will be of practical value in both reference and diagnostic laboratories.

Bacterial Capsules↗

PubMed2006

[Effects of different doses of hydrocortisone on the disorder of coagulation in rats at early stage of septic shock].

OBJECTIVE: To investigate the effects of different doses of hydrocortisone (HC) on the disorder of coagulation in rats at early stage of septic shock. METHODS: The model of early septic shock accompanied by the disorder of coagulation in rats was set up by bolus injection of lipopolysaccharide (LPS) at 25 mg/kg through right femoral vein. Forty male Wistar rats were randomly divided into the following 5 groups: normal control (LPS and HC were substituted by same volume of normal saline solution), shock group (HC was substituted by same volume of normal saline), high-dose HC (HD group, HC 100 mg/kg), medium-dose HC (MD group, HC 50 mg/kg) and low-dose HC (LD group, HC 5 mg/kg). Four hours after the HC treatment, the blood specimens were collected for the count of blood platelet (PLT), the activity of antithrombin III (ATIII), the content of D-dimer and von Willebrand factor (vWF). RESULTS: The count of PLT (x 10(9)/L) and the activities of ATIII (%) in shock group (586.00 +/- 71.179 and 50.600 +/- 19.248) were significantly lower than that in normal control group (1012.600 +/- 20.852 and 89.200 +/- 12.109), and the level of D-dimer (microg/dl) and vWF (%) in LPS group (1.680 +/- 0.999 and 7.288 +/- 0.652) as significantly higher than that in normal control group (0.66 +/- 0.772 and 3.656 +/- 1.407), P < 0.05. After HC treatment, the disorder of coagulation was attenuated to different degree. However, significant difference was found between HD, MD groups and shock group only in the count of PLT (P = 0.000), and there were no significant differences between HD, MD groups and shock group in the other three indices. Significant improvements were found in LD group (P < 0.05) in all the four indices and there were no significant differences between LD group and normal group in D-dimer and vWF. The effects of medium-dose HC was between LD and HD groups, and there were no significant differences between HD and MD group, P > 0.05. CONCLUSIONS: The results indicated that different doses of HC had different effects on coagulation in early stage of septic shock in rats. Low-dose HC may ameliorate the disorder of coagulation in early septic shock in rats. High-dose and medium-dose of HC had no significant improving effects on the disorder of coagulation.

Animals↗

PubMed2006

[Sequence of Escherichia coli O11 O-antigen gene cluster and identification of molecular markers specific to O11].

Escherichia coli O11 belongs to Shiga toxin-producing Escherichia coli (STEC), which can cause food-borne disease, hemorrhagic colitis, and hemolytic-uremic syndrome (HUS) in humans. Because of its character of specificity, the O-antigen gene cluster provides the best material for the selection of molecular markers which can be used for rapid genotyping of bacterial strain. In this study, the E.coli O11 O-antigen gene cluster was amplified by Long-range PCR and was sequenced using Shotgun-sequencing approach. Twelve open reading frames were assigned functions on the basis of homology in the E. coli O11 O-antigen gene cluster, including UDP-N-acetyl glucosamine-4-epimerase gene (gne), genes responsible for the biosynthesis of GDP-L-fucose (gmd, fcl, gmm, manC, manB), glycosyl transferase genes, O-unit flippase gene (wzx) and O-antigen polymerase gene (wzy). By polymerase chain reaction against representative stains for all the 166 E. coli and 43 Shigella O serotypes, two genes and four pairs of primers were identified to be specific to E. coli O11. Further PCR was done to detect E. coli O11 from the environmental specimens, and the sensitivities for detecting E.coli O11 from the pork and dejecta specimens were 0.25 cfu/g and 2.5 x 10(3) cfu/g, respectively. Moreover, eight probes were designed and proved to be unique to E. coli O11, which provides the basis for a sensitive test of the rapid detection of E. coli O11 by DNA microarray method.

Biomarkers↗

PubMed2006

[Changes of serum neuron specific enolase in rats with septic shock].

OBJECTIVE: To study the changes of serum neuron specific enolase in rats with septic shock. METHODS: The model of septic shock was set up by injection of lipopolysaccharide (LPS, from Escherichia coil O55: B5) at a dose of 25 mg/kg through femoral vein. Twenty male Wistar rats were randomly divided into 2 groups: normal control group (LPS was substituted by same volume of normal saline solution) and septic shock group. Six hours after the septic shock model formed, whole blood was taken for measuring the serum neuron specific enolase (NSE). The brains of the rats were taken for histopathological examination. RESULTS: The serum NSE of septic shock group was significantly higher than that of control group [(10.0781 +/- 0.526) microg/L vs. (3.7188 +/- 0.602) microg/L, P < 0.05]. Neurons were severely damaged 6 hours after injection of LPS. Neuronal necrosis and the damage of blood-brain barrier were seen by light and electron microscope in septic shock group but not in the control group. CONCLUSION: NSE in serum increased when septic encephalopathy occurred, which indicated that NSE might become a marker of neural damage in septic shock.

Animals↗