Guang Yang

Academy of Military Medical Sciences, T’ien-ching-shih, Tianjin Shi, China

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Publications (56)190.16 Total impact

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    ABSTRACT: Staphylococcus aureus causes a wide range of infectious diseases. Treatment of these infections has become increasingly difficult due to the widespread emergence of antibiotic-resistant strains; therefore, it is essential to explore effective alternatives to antibiotics. A secreted protein of S. aureus, known as eLtaS, is an extracellular protein released from the bacterial membrane protein, LtaS. However, the role of eLtaS in S. aureus pathogenesis remains largely unknown. Here we show eLtaS dramatically aggravates S. aureus infection by binding to C3b and then inhibiting the phagocytosis of C3b-deposited S. aureus. Furthermore, we developed a monoclonal antibody against eLtaS, MAE4, which neutralizes the activity of eLtaS and blocks staphylococcal evasion of phagocytosis. Consequently, MAE4 is capable of protecting mice from lethal S. aureus infection. Our findings reveal that targeting of eLtaS by MAE4 is a potential therapeutic strategy for the treatment of infectious diseases caused by S. aureus.
    Preview · Article · Nov 2015 · Scientific Reports
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    ABSTRACT: Clustered, regularly interspaced, short palindromic repeats (CRISPR) act as an adaptive RNA-mediated immune mechanism in bacteria. They can also be used for identification and evolutionary studies based on polymorphisms within the CRISPR locus. We amplified and analyzed six CRISPR loci from 237 Shigella strains belonging to the four species groups, as well as 13 Escherichia coli strains. The CRISPR-associated (cas) gene sequence arrays of these strains were screened and compared. The CRISPR sequences from Shigella were conserved among subtypes, suggesting that CRISPR may represent a new identification tool for the detection and discrimination of Shigella species. Secondary structure analysis showed a different stem-loop structure at the terminal repeat, suggesting a distinct recognition mechanism in the formation of crRNA. In addition, the presence of "self-target" spacers and polymorphisms within CRISPR in Shigella indicated a selective pressure for inhibition of this system, which has the potential to damage "self DNA". Homology analysis of spacers showed that CRISPR might be involved in the regulation of virulence transmission. Phylogenetic analysis based on CRISPR sequences from Shigella and E. coli indicated that although phenotypic properties maintain convergent evolution, the four Shigella species do not represent natural groupings. Surprisingly, comparative analysis of Shigella repeats with other species provided new evidence for CRISPR horizontal transfer. Our results suggested that CRISPR analysis is applicable for the detection of Shigella species and for investigation of evolutionary relationships.
    No preview · Article · Sep 2015 · RNA biology
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    ABSTRACT: The epidemiological features of Ebola virus disease (EVD) has been significantly changed in West Africa according to WHO report. In the study, we described the new epidemiological features and prevalence trends for EVD in Guinea, Liberia, and Sierra Leone. We found the Ebola outbreak would be end in June 2015. Copyright © 2015. Published by Elsevier Ltd.
    Preview · Article · Jul 2015 · International journal of infectious diseases: IJID: official publication of the International Society for Infectious Diseases
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    ABSTRACT: Shigella flexneri is an important etiological agent of bacillary dysentery in developing countries. The Hfq protein is thought to play a major regulatory role in various cellular processes in this organism. However, the roles of Hfq in stress tolerance and virulence in S. flexneri in response to environmental stress have not been fully studied. In this study, hfq was highly expressed when S. flexneri was exposed to low pH. Growth retardation was observed in the hfq deletion mutant at pH values ranging from 5.0 to 7.0 and the survival rate of the mutant strain was reduced by 60% in acidic conditions (pH 3.0) compared with the wild-type strain. Additionally, competitive invasion assays in HeLa cells and lung invasion assays showed that the virulence of the hfq deletion mutant was significantly decreased. An evaluation of the mechanism revealed that, along with the expression of the Type III secretion system genes, acid resistance genes were also increased with acid stress. Interestingly, a statistically strong linear correlation was observed between the expression of hfq and Type III secretion system genes, as well as between hfq and acid resistance genes, under various pH conditions. In this study, we provide evidence that Hfq regulates genes related to acid resistance for survival under acid stress and controls virulence through the positive regulation of Type III secretion systems. Importantly, we propose that hfq is a key factor in maximal adaptation to host acid stress during infection, regulating acid stress tolerance and virulence in response to acid stress in S. flexneri. Copyright © 2015. Published by Elsevier Masson SAS.
    Full-text · Article · Jun 2015 · Research in Microbiology

  • No preview · Article · Apr 2015 · The Journal of infection
  • Jun Yan · Yu Liu · Yaping Gao · Jie Dong · Chunhua Mu · Di Li · Guang Yang
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    ABSTRACT: RNAIII is known as the key effector of staphylococcal accessory gene regulator (agr) quorum-sensing system, which plays a central role in the pathogenesis of Staphylococcus aureus. As a regulatory RNA, RNAIII regulates multiple targets, including exoproteins and cell-wall-associated proteins. Lipoteichoic acid synthase (LtaS) is involved in the synthesis of lipoteichoic acid (LTA) that is one of the major components of cell wall. The chemical compound targeting to LtaS decreases S. aureus growth via blocking LTA production. Until now, the regulatory mechanism of LtaS expression is still not clear. The level of ltaS mRNA in S. aureus is analyzed by semi-quantitative RT-PCR analysis and qRT-PCR. The protein level of LtaS is determined by Western blotting. The putative interaction sites between RNAIII and LtaS mRNA are predicted. And LtaS-5′UTR-lacZ and LtaS-5′UTR-mutant-lacZ reporter vectors are constructed according to the putative interaction sites. Our data show that the expression of ltaS is regulated by RNAIII in S. aureus. The level of LtaS is significantly higher in the RNAIII deficient strain compared to its parent strain. In the further investigation, 5′UTR of ltaS was predicted to be the putative interaction site of RNAIII. The results of detection of β-galactosidase activities suggest that RNAIII can inhibit the expression level of LtaS through acting on the 5′UTR region of LtaS mRNA. Our finding presents that LtaS is another target of RNAIII and RNAIII suppresses the expression of LtaS via acting as an antisense RNA in S. aureus.
    No preview · Article · Oct 2014 · Journal of Basic Microbiology

  • No preview · Article · Sep 2014 · Clinical Infectious Diseases
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    ABSTRACT: Many outbreaks of A(H1N1)pdm09 influenza have occurred in schools with a high population density. Containment of school outbreaks is predicted to help mitigate pandemic influenza. Understanding disease transmission characteristics within the school setting is critical to implementing effective control measures. Based on a school outbreak survey, we found almost all (93.7%) disease transmission occurred within a single grade, only 6.3% crossed grades. Transmissions originating from freshmen exhibited a star-shaped network; other grades exhibited branch- or line-shaped networks, indicating freshmen have higher activity and are more likely to cause infection. R0 for freshmen, calculated as 2.04, estimated as 2.76, was greater than for other grades (P < 0.01). Without intervention, the estimated number of cases was much greater when the outbreak was initiated by freshmen than by other grades. Furthermore, the estimated number of cases required to be under quarantine and isolation for freshmen was less than that of equivalent other grades. So we concluded that different grades have different transmission mode. Freshmen were the main facilitators of the spread of A(H1N1)pdm09 influenza during this school outbreak, so control measures (e.g. close contact isolation) priority used for freshmen would likely have effectively reduced spread of influenza in school settings.
    Full-text · Article · Aug 2014 · Scientific Reports
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    ABSTRACT: A new crosslinking reaction between benzoxazine and benzoxazole was discovered by investigating the heat-curing reaction of bisphenol A/aniline-based benzoxazine monomer with a polybenzoxazole (PBO) model compound. This new crosslinking reaction provides a facile and straightforward method for the preparation of high-performance crosslinked PBO/polybenzoxazine copolymer composites.
    Preview · Article · Jun 2014 · Journal of Polymer Science Part A Polymer Chemistry
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    Jian Gong · Dongzhi Li · Jun Yan · Yu Liu · Di Li · Jie Dong · Yaping Gao · Tao Sun · Guang Yang
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    ABSTRACT: Intracranial abscesses are associated with high mortality. Staphylococcus aureus is one of the main pathogens that cause intracranial infection. Until now, there is no report to identify the key effectors of S. aureus during the intracranial infection. The murine intracranial abscesses model induced by S. aureus was constructed. The vital sign and survival rate of mice were observed to evaluate the infection. Histological examination was used to diagnose the pathological alterations of mouse tissues. The sensitivity of S. aureus to whole blood was evaluated by whole-blood killing assay. In murine intracranial abscesses model, it was shown that the mortality caused by the accessory gene regulator (agr) locus deficient strain was significant decreased compared with its parent strain. Moreover, we found that RNAIII, the effector of agr system, was essential for the intracranial infection caused by S. aureus. In the further investigation, it was shown that restoration the expression of α-toxin in agr deficient strain could partially recover the mortality in the murine intracranial abscesses model. Our data suggested that the agr system of S. aureus is an important virulence determinant in the induction and mortality of intracranial abscesses in mice.
    Preview · Article · May 2014 · The Brazilian journal of infectious diseases: an official publication of the Brazilian Society of Infectious Diseases
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    ABSTRACT: The Polyaniline (PANI)/Polybenzobisoxazole (PBO) composites doped with phosphoric acid and methanesulfonic acid are prepared by solution blending. It was found that the PANI exhibited highly homogeneous dispersion in the PBO matrix. The protonization of different solvents could affect the shape and size of PANI in the composites. With the increase of PANI, the conductivity of composites increases. The conductive behavior of composites was also studied based on percolation threshold and VRH theories. It was found that the VRH models for PANI/MSA/PBO and PANI/H3PO4/PBO were different.
    No preview · Article · May 2014 · Materials Letters
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    ABSTRACT: Two series of polybenzoxazoles (PBOs) containing trifluoromethyl or sulfone groups were synthesized via solution condensation polymerization. The polymers were characterized by FT-IR, 1H-NMR, thermogravimetric analysis (TGA), UV-vis absorption, and photoluminescence (PL) spectroscopy. The solubility of these polymers was greatly enhanced over that of pure PBO and some of them could dissolve well in polar solvents, such as N-methyl-2-pyrrolidone (NMP) and 2,5-Dimethylfuran (DMF). Due to the introduction of trifluoromethyl and sulfone groups, the UV absorption peaks and the emission peaks of all the polymers blue shifted, compared with those of pure PBO. The polymers derived from 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (6FAP) had a lower dielectric constant, which is due to the strong electron-withdrawal inductive effect, compared to that of the polymers derived from 3,3-diamino-4,4-dihydroxydiphenylsulfone (6SAP).
    No preview · Article · Jan 2014 · Journal of Macromolecular Science Part B
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    Jian Gong · Dongzhi Li · Jun Yan · Yu Liu · Di Li · Jie Dong · Yaping Gao · Tao Sun · Guang Yang
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    ABSTRACT: Background Intracranial abscesses are associated with high mortality. Staphylococcus aureus is one of the main pathogens that cause intracranial infection. Until now, there is no report to identify the key effectors of S. aureus during the intracranial infection. Methods The murine intracranial abscesses model induced by S. aureus was constructed. The vital sign and survival rate of mice were observed to evaluate the infection. Histological examination was used to diagnose the pathological alterations of mouse tissues. The sensitivity of S. aureus to whole blood was evaluated by whole-blood killing assay. Results In murine intracranial abscesses model, it was shown that the mortality caused by the accessory gene regulator (agr) locus deficient strain was significant decreased compared with its parent strain. Moreover, we found that RNAIII, the effector of agr system, was essential for the intracranial infection caused by S. aureus. In the further investigation, it was shown that restoration the expression of α-toxin in agr deficient strain could partially recover the mortality in the murine intracranial abscesses model. Conclusion Our data suggested that the agr system of S. aureus is an important virulence determinant in the induction and mortality of intracranial abscesses in mice.
    Preview · Article · Jan 2014
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    ABSTRACT: Objective: To investigate whether the expression level of valosin-containing protein (VCP) is correlated with the prognosis of primary orbital mucosa-associated lymphoid tissue (MALT) lymphoma. Methods: VCP expression in 58 samples from primary orbital MALT lymphoma patients was determined by immunohistochemisty using monoclonal antibodies. Correlations between VCP expression level and prognosis were clarified by statistical analysis. Results: It was found that the percentage of VCP positive cells in samples of primary orbital MALT lymphoma ranged from 32% to 95%. The samples were divided into two groups (level 1 and level 2) according to the median value (45%) of the percentage of VCP positive cells. It was found that the expression level of VCP was significantly correlated with recurrence (P=0.003) and tumor size (P=0.008). At the same time, the 5-year disease-free and overall survival rate of patients of level 1 was significantly better than that of level 2 (P=0.001; P=0.032). There was no observed correlation between the expression level of VCP and other clinical features. Conclusion: VCP could be a useful marker for predicting the prognosis of primary orbital MALT lymphoma.
    Preview · Article · Nov 2013 · Asian Pacific journal of cancer prevention: APJCP
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    ABSTRACT: MicroRNAs have been implicated in the regulation of gene expression of various biological processes in a post-transcriptional manner under physiological and pathological conditions including host responses to viral infections. The 2009 pandemic H1N1 influenza virus is an emerging reassortant strain of swine, human and bird influenza virus that can cause mild to severe illness and even death. To further understand the molecular pathogenesis of the 2009 pandemic H1N1 influenza virus, we profiled cellular microRNAs of lungs from BALB/c mice infected with wild-type 2009 pandemic influenza virus A/Beijing/501/2009 (H1N1) (hereafter referred to as BJ501) and mouse-adapted influenza virus A/Puerto Rico/8/1934 (H1N1) (hereafter referred to as PR8) for comparison. Microarray analysis showed both the influenza virus BJ501 and PR8 infection induced strain- and temporal-specific microRNA expression patterns and that their infection caused a group of common and distinct differentially expressed microRNAs. Characteristically, more differentially expressed microRNAs were aroused on day 5 post infection than on day 2 and more up-regulated differentially expressed microRNAs were provoked than the down-regulated for both strains of influenza virus. Finally, 47 differentially expressed microRNAs were obtained for the infection of both strains of H1N1 influenza virus with 29 for influenza virus BJ501 and 43 for PR8. Among them, 15 microRNAs had no reported function, while 32 including miR-155 and miR-233 are known to play important roles in cancer, immunity and antiviral activity. Pathway enrichment analyses of the predicted targets revealed that the transforming growth factor-β (TGF-β) signaling pathway was the key cellular pathway associated with the differentially expressed miRNAs during influenza virus PR8 or BJ501 infection. To our knowledge, this is the first report of microRNA expression profiles of the 2009 pandemic H1N1 influenza virus in a mouse model, and our findings might offer novel therapy targets for influenza virus infection.
    Full-text · Article · Sep 2013 · PLoS ONE

  • No preview · Article · Sep 2013 · Clinical Infectious Diseases
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    ABSTRACT: A series of composites of Polyaniline (PANI) and Polybenzobisoxazole (PBO) nanocomposites were prepared with different PANI compositions. The methanesulfonic acid (MSA) was used as dopant and solvent. The structures and morphology of the obtained nanocomposites were fully characterized by FT-IR, TGA, SEM and TEM. The effect of mass fractions of PANI, temperature and frequency on the dielectric property was studied. The PANI exhibited highly homogeneous dispersion in PBO matrix. The dielectric constants of the composites increased with PANI content and the testing temperature and decreased with frequency.
    No preview · Article · Sep 2013
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    ABSTRACT: This article reports the in situ preparation of fluorinated poly-(2,5-thienylbenzobisoxazole)/polyhedral oligomeric silsesquioxane (6FPBOT/POSS) nanocomposites and their chemical and physical properties. POSS participated in the polymerization reaction and thus led to the homogenous dispersion of POSS nanoparticles in the 6FPBOT matrix. The structures and morphology of the obtained nanocomposites were fully characterized by Fourier transform infrared spectroscopy, wide-angle X-ray scattering, thermogravimetric analysis, and transmission electron microscopy. The nanocomposites exhibited excellent thermal stability. The introduction of POSS evidently increased the mechanical properties (tensile strength and tensile modulus) of the nanocomposites and significantly enhanced the quantum yield of 6FPBOT by reducing the degree of interchain aggregation. The dielectric constants of the nanocomposites decreased with increasing POSS content. The dielectric constant of the materials decreased from 2.56 for the 6FPBOT to 2.11 for the 6FPBOT–POSS nanocomposite with 5% POSS.
    No preview · Article · Jul 2013 · Synthetic Metals
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    ABSTRACT: We identified 3 atypical Shigella flexneri varieties in China, including 92 strains with multidrug resistance, distinct pulse types, and a novel sequence type. Atypical varieties were prevalent mainly in developed regions, and 1 variant has become the dominant Shigella spp. serotype in China. Improved surveillance will help guide the prevention and control of shigellosis.
    Full-text · Article · Jul 2013 · Emerging Infectious Diseases
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    ABSTRACT: Objective To investigate why the level of Lyn is significantly decreased in B cells from a majority of patients with systemic lupus erythematosus (SLE) and to determine the role of microRNA-30a (miR-30a) in SLE B cell hyperactivity. Methods Luciferase reporter gene assays were performed to identify the interaction between miR-30a and the 3′-untranslated region (3′-UTR) of Lyn. Levels of miR-30a in B cells were determined by TaqMan quantitative polymerase chain reaction (qPCR), Lyn messenger RNA levels were tested with real-time qPCR, and protein levels of Lyn were determined using Western blotting. The quantity of IgG was determined by enzyme-linked immunosorbent assay. The proliferation of B cells was measured using 3H-thymidine incorporation. ResultsIn B cell lines, miR-30a, but not miR-30b, miR-30c, miR-30d, or miR-30e, could specifically bind the 3′-UTR of Lyn, and overexpression of miR-30a inhibited the levels of Lyn. The level of miR-30a in B cells was significantly higher in SLE patients compared to healthy donors. The level of miR-30a was negatively associated with the level of Lyn in B cells. Overexpression of miR-30a was found to promote B cell proliferation and the production of IgG antibodies. The effect of miR-30a could be abrogated by inducing overexpression of Lyn in B cells. Conclusion These results reveal that elevated expression of miR-30a is responsible for the reduction in levels of Lyn in B cells from patients with SLE, suggesting that miR-30a plays an important role in B cell hyperactivity.
    Full-text · Article · Jun 2013 · Arthritis & Rheumatology

Publication Stats

723 Citations
190.16 Total Impact Points

Institutions

  • 2012-2015
    • Academy of Military Medical Sciences
      T’ien-ching-shih, Tianjin Shi, China
  • 2012-2014
    • East China University of Science and Technology
      • School of Materials Science and Engineering
      Shanghai, Shanghai Shi, China
  • 2013
    • Peking University
      Peping, Beijing, China
  • 2003-2011
    • Government of the People's Republic of China
      Peping, Beijing, China
  • 2009
    • Beijing FivePlus Molecular Medicine Institute
      Peping, Beijing, China
    • Beijing Institute Of Technology
      Peping, Beijing, China