Biomedical subjects

Yiqin Wang

Publications and source records attributed to Yiqin Wang.

11 recordsLinked to original sources

PubMed2006

S-nitrosylation: an emerging redox-based post-translational modification in plants.

S-nitrosylation, the covalent attachment of a nitric oxide moiety to a cysteine thiol, is now established as a key post-translational modification in animals. This process has been shown to regulate the function of a wide variety of regulatory, structural, and metabolic proteins. The emerging evidence now suggests that S-nitrosylation may also have a central function in plant biology.

Gene Expression Regulation, Plant↗

PubMed2006

Oral administration of exopolysaccharide from Aphanothece halophytica (Chroococcales) significantly inhibits influenza virus (H1N1)-induced pneumonia in mice.

The halophilous cyanobacterium Aphanothece halophytica releases large sums of single type sulfated exopolysaccharide in late logarithmic growth phase in culture. This polysaccharide contained sulfate up to 34.46% of the total moieties in the molecular. As a sulfated polysaccharide that can be biosynthesized in large quantities, however, its antiviral activity has not yet been reported. In this study, we examined effects of exopolysaccharide from A. halophytica Fremy (EPAH) on influenza virus A FM (H1N1) (FM1)-induced pneumonia and reduction in immunocompetence in mice. Previous and simultaneous treatment of EPAH at a dose of 60 mg/kg significantly inhibited pneumonia in FM1-infected mice by 30.4% and 26.7%, respectively. In post-treatment, EPAH displayed its most effective inhibition at a dose of 80 mg/kg with the inhibition rate at 18.69%. Simultaneous treatment of FM1-infected mice with EPAH showed effective improvement on reduction of lymphocyte number with its most effective dose at 60 mg/kg. FM1-infected mice simultaneously received EPAH at a dose of 40 mg/kg also acquired obvious enhancement on release of IL-2 on day 15, and those received EPAH at a dose of 60 mg/kg showed similar enhancement on day 10. Simultaneous treatment with EPAH indicated remarkable recovery or improvement of FM1-induced reduction of IL-1beta level and phagocytic capacity of RES. Simultaneous treatment with EPAH significantly resumed the cytolytic activity of natural killer cells in FM1-infected or CP treated mice at doses of 40 and 60 mg/kg. These results suggested that EPAH is an effective agent against FM1. The mechanisms of its action might be mediated, at least in part, by modulating the host immune system and the interaction positive charges in EPAH and negative charges FM1.

Administration, Oral↗

PubMed2006

GOLD HULL AND INTERNODE2 encodes a primarily multifunctional cinnamyl-alcohol dehydrogenase in rice.

Lignin content and composition are two important agronomic traits for the utilization of agricultural residues. Rice (Oryza sativa) gold hull and internode phenotype is a classical morphological marker trait that has long been applied to breeding and genetics study. In this study, we have cloned the GOLD HULL AND INTERNODE2 (GH2) gene in rice using a map-based cloning approach. The result shows that the gh2 mutant is a lignin-deficient mutant, and GH2 encodes a cinnamyl-alcohol dehydrogenase (CAD). Consistent with this finding, extracts from roots, internodes, hulls, and panicles of the gh2 plants exhibited drastically reduced CAD activity and undetectable sinapyl alcohol dehydrogenase activity. When expressed in Escherichia coli, purified recombinant GH2 was found to exhibit strong catalytic ability toward coniferaldehyde and sinapaldehyde, while the mutant protein gh2 completely lost the corresponding CAD and sinapyl alcohol dehydrogenase activities. Further phenotypic analysis of the gh2 mutant plants revealed that the p-hydroxyphenyl, guaiacyl, and sinapyl monomers were reduced in almost the same ratio compared to the wild type. Our results suggest GH2 acts as a primarily multifunctional CAD to synthesize coniferyl and sinapyl alcohol precursors in rice lignin biosynthesis.

Alcohol Oxidoreductases↗

PubMed2005

A central role for S-nitrosothiols in plant disease resistance.

Animal S-nitrosoglutathione reductase (GSNOR) governs the extent of cellular S-nitrosylation, a key redox-based posttranslational modification. Mutations in AtGSNOR1, an Arabidopsis thaliana GSNOR, modulate the extent of cellular S-nitrosothiol (SNO) formation in this model plant species. Loss of AtGSNOR1 function increased SNO levels, disabling plant defense responses conferred by distinct resistance (R) gene subclasses. Furthermore, in the absence of AtGSNOR1, both basal and nonhost disease resistance are also compromised. Conversely, increased AtGSNOR1 activity reduced SNO formation, enhancing protection against ordinarily virulent microbial pathogens. Here we demonstrate that AtGSNOR1 positively regulates the signaling network controlled by the plant immune system activator, salicylic acid. This contrasts with the function of this enzyme in mice during endotoxic shock, where GSNOR antagonizes inflammatory responses. Our data imply SNO formation and turnover regulate multiple modes of plant disease resistance.

Arabidopsis↗

PubMed2005

[Correlations between BCG-PSN and tuberculin responses].

OBJECTIVE: To investigate the correlations between tuberculin responses and allergic rhinitis treated by BCG-PSN. METHOD: A total 60 patients with allergic rhinitis were randomly divided into BCG-PSN treated group and control group. All patients were given purified protein derivate (PPD), and PPD induration were recorded after 72 h, also the eosinophil cationic protein (ECP) and total IgE (TIgE) in serum were assayed with Pharmacia UniCAP System. RESULT: ECP and tIgE levels of patients treated by BCG-PSN were significantly lower than before treatment (P < 0.01). 37.5% patients who had negative reaction had induration after treatment using BCG-PSN. CONCLUSION: These results indicate that exposure BCG-PSN can correct the imbalance state of Th1 and Th2 cytokines and inhibit allergic airway inflammation and control allergic rhinitis.

Adolescent↗

PubMed2005

[Tongue image color recognition in traditional Chinese medicine].

The problem of color recognition of substances and coats in tongue images was decomposed into two steps, i. e. region separation and color recognition. In the first step, a new method based on the JSEG and the k-NN algorithms was proposed to separate coats and substances, where a prior template and some standard color patches were designed to assist the classification. Color recognition in a fine scale was carried out by the nearest neighbour method on the basis of the first step. The experiments showed the method proposed in this paper was simple and highly robust, and can be applied to tongue characterization effectively. In addition, the two important preprocessing algorithms namely color calibration and segmentation of tongue images were improved to obtain better results than the former.

Color↗

PubMed2005

[Image segmentation in tongue characterization].

Tongue diagnosis is one of the essential methods of traditional Chinese medical diagnosis. The accuracy of tongue diagnosis can be improved by tongue characterization. Tongue area segmentation and homogeneous regions segmentation in tongue are important contents of preprocess of tongue image. An algorithm based on edge detection and Gradient vector flow (GVF) active contour for tongue area segmentation and another algorithm based on unsupervised segmentation of color-texture for homogeneous regions segmentation in tongue were presented. Totally about 1500 tongue images were collected. Results of tongue area segmentation achieved accuracy rate of 94.3% and results of homogeneous regions segmentation in tongue were approved by traditional Chinese medical experts. The experiments results show robustness of the algorithms. This work establishes solid foundation for feature selecting of Tongue diagnosis.

Algorithms↗

PubMed2004

Study on cartilaginous and muscular strains of rat trachea.

This paper introduces a new method, termed Twice Cutting, for obtaining the zero-stress states of cartilage and muscle of trachea. The method applied cuts at the two junctions of tracheal cartilage and muscle perpendicular to the tangent lines of cartilage at its tips. The cartilaginous and muscular opening angles are defined for the first time in Twice Cutting methods. Based on the analysis of cartilaginous and muscular geometric information in no-load and zero-stress states, it is found that there are compressive and tensile residual strains in the inner and outer walls of the cartilage respectively. Residual strains at the muscular inner wall of tracheal rings near bifurcation are negative, whereas those of other rings are positive, and residual strains at outer wall of all rings are positive. This phenomenon of tracheal muscle residual strains is different from those of vessel etc. The results also show that the absolute values of cartilaginous strains are considerably smaller than that of muscular ones, with the ratio being around 0.05. The values of all the tracheal parameters, including residual strains and opening angles, are reducing with the increasing value of tracheal rings' position. So the consequences obtained in this paper not only indicate that the trachea is a non-uniform tissue along the circumferential and axial directions, but also reveal the differences between the trachea and other living tissues, such as vessel, esophagus. This is a basic research for further work, such as determining stress in trachea, to which the cartilaginous and muscular zero-stress states should be referred.

Animals↗

PubMed2003

Drosophila morgue and the intersection between protein ubiquitination and programmed cell death.

In Drosophila, cell survival decisions are mediated by the integrated functions of the Grim-Reaper death activators and Inhibitor-of-Apoptosis-Proteins (IAPs), such as DIAP1, to regulate caspase activities. We recently identified a gene that enhances the actions of the Grim-Reaper proteins and negatively regulates the levels of DIAP1 protein. This gene, morgue, encodes a novel protein that contains both an F box and a ubiquitin conjugase domain. Interestingly, the Morgue conjugase domain lacks the active site cysteine required for covalent linkage to ubiquitin. Morgue could target IAPs and other proteins for ubiquitination and proteasome-dependent turnover by acting either in an SCF ubiquitin E3 ligase complex, or as a ubiquitin E2 conjugase enzyme variant (UEV) in conjunction with a catalytically active E2 conjugase. Morgue is evolutionarily conserved, as a Morgue ortholog was identified from the mosquito, Anopheles gambiae. Elucidation of morgue function should provide novel insights into the mechanisms of ubiquitination and programmed cell death.

Amino Acid Sequence↗

PubMed2003

The site-directed mutagenesis of gastrodia anti-fungal protein mannose-binding sites and its expression in Escherichia coli.

Gastrodia anti-fungal protein (GAFP) displays strong inhibitory activity against certain fungal pathogens. Five GAFP analogues with different mutations at mannose-binding sites and the wild-type one were expressed and purified in Escherichia coli. The inhibitory analysis of the purified various GAFPs against the growth of Trichoderma viride indicates that single amino acid mutated-type GAFPs have inhibitory activity, but its activity is much less than the wild-type one. The double and triplicate amino acids mutated GAFPs have very low inhibitory activity. For the first time it was proved that GAFP mannose-binding sites play key role in anti-fungi process.

Antifungal Agents↗

PubMed2002

Drosophila Morgue is an F box/ubiquitin conjugase domain protein important for grim-reaper mediated apoptosis.

In Drosophila melanogaster, apoptosis is controlled by the integrated actions of the Grim-Reaper (Grim-Rpr) and Drosophila Inhibitor of Apoptosis (DIAP) proteins (reviewed in refs 1 4). The anti-apoptotic DIAPs bind to caspases and inhibit their proteolytic activities. DIAPs also bind to Grim-Rpr proteins, an interaction that promotes caspase activity and the initiation of apoptosis. Using a genetic modifier screen, we identified four enhancers of grim-reaper-induced apoptosis that all regulate ubiquitination processes: uba-1, skpA, fat facets (faf), and morgue. Strikingly, morgue encodes a unique protein that contains both an F box and a ubiquitin E2 conjugase domain that lacks the active site Cys required for ubiquitin linkage. A reduction of morgue activity suppressed grim-reaper-induced cell death in Drosophila. In cultured cells, Morgue induced apoptosis that was suppressed by DIAP1. Targeted morgue expression downregulated DIAP1 levels in Drosophila tissue, and Morgue and Rpr together downregulated DIAP1 levels in cultured cells. Consistent with potential substrate binding functions in an SCF ubiquitin E3 ligase complex, Morgue exhibited F box-dependent association with SkpA and F box-independent association with DIAP1. Morgue may thus have a key function in apoptosis by targeting DIAP1 for ubiquitination and turnover.

Amino Acid Sequence↗