Objective:To investigate clinicopathological,bacteriological and pathological aspects of an experimental infection with Yersinia pseudotuberculosis(Y.pseudotuberculosis)in hares in order to verify the efficacy of sero...Objective:To investigate clinicopathological,bacteriological and pathological aspects of an experimental infection with Yersinia pseudotuberculosis(Y.pseudotuberculosis)in hares in order to verify the efficacy of serology for the in vivo diagnosis.Moreover,the pathogenicity of two Y.pseudotuberculosis strains was investigated in order to detect potential differences.Methods:Twelve European brown hares(Lepus europaeus,Pallas)were experimentally infected per os and via conjunctival mucosae with Y.pseudotuberculosis:six subjects were infected with a strain isolated from a naturally infected hare(YpH)and six subjects with a strain isolated from a naturally infected rabbit(YpR).Two hares were used as negative controls.All animals were subjected to clinical,bacteriological and serological examinations during 9 weeks following the infection and,at the end of the control period,subjects still alive were euthanized and submitted to a complete post mortem examination.Results:All faecal samples collected during the control period were positive for bacteriological examinations and to a PCR for the inv gene of Y.pseudotuberculosis,while only one Yp H-infected hare showed a positive haemocultures.From the 2nd to the 9th week post infection(pi),serological analysis revealed specific antibodies with titers ranging from 1:10 to 1:160 in all YpH-infected and two YpR-infected subjects.All the Yp H-infected and two Yp R-infected hares scored positive for Y.pseudotuberculosis by means of bacteriological investigations.Grossly,suppurative multifocal lesions were detected in liver,spleen,kidney and sub-mandibular lymph nodes in both YpH-and YpR-infected hares and confirmed with histopathology.Pulmonary lesions were observed only in Yp H-infected subjects.Immunohistochemistry confirmed the presence of bacterial antigen in all infected animals.Conclusion:Results of this study revealed that YpH strain is more pathogenic for hares than the YpR strain;moreover the serological test performed in this study could be used for the diagnosis of pseudotuberculosis in hares,whereas post mortem diagnosis should be confirmed by means of bacteriological examination,PCR,histopathology and immunohistochemistry.展开更多
Corynebacterium pseudotuberculosis is an infectious agent that occurs in small ruminants causing caseous lymphadenitis, and more rarely in humans causing lymphadenitis and pneumonia. The breeding small ruminants have ...Corynebacterium pseudotuberculosis is an infectious agent that occurs in small ruminants causing caseous lymphadenitis, and more rarely in humans causing lymphadenitis and pneumonia. The breeding small ruminants have great economic importance in Brazil. Rural farm workers and veterinary students who acquired this disease suffered from weakening symptoms for weeks, and the identification of the etiological agent was time-consuming and complex. Due to the low prevalence of case records, there is probably no available commercial diagnostic kit for C. pseudotuberculosis infection in humans. This study aimed to describe human seroreactivity to secreted antigens from C. pseudotuberculosis. Reactivity of serum from farm workers (n = 14), individuals who work with the bacillus at laboratory (n = 8) or individuals without contact (n = 25) was tested with secreted proteins from PAT10 strain of C. pseudotuberculosis by Western blotting. Samples of all (100%) farm workers showed reactivity to 31 kDa, 71 kDa and 164 kDa proteins, while laboratory workers showed 87.5%, 62.5 % and 37.5%, and no-contact 20%, 0% and 16%, respectively. All sera recognized the 275 kDa protein. Our data suggest that C. pseudotuberculosis secreted proteins are antigenic in humans and the recognition profiles allowed the identification of individuals with and without prior contact with this bacillus. This is the first paper which describes human reactivity to C. pseudotuberculosis in serum samples of workers in Brazil.展开更多
Caseous lymphadenitis (CL) is a chronic infectious disease caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) that is transmitted mainly by contact with contaminated exudate wounds. Caseous lymphaden...Caseous lymphadenitis (CL) is a chronic infectious disease caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) that is transmitted mainly by contact with contaminated exudate wounds. Caseous lymphadenitis affects different species of animals and is considered an occupational zoonotic disease. CL is responsible for important economic losses in the small ruminant industry, which include decreased production, damaged quality of milk and wool, reproductive disorders, total or partial confiscation of carcasses, and depreciation of the skin. Caseous lymphadenitis disease can present in two clinical pictures: a skin or superficial picture and a visceral or deep picture. The presumptive diagnosis of CL in the skin is based on the exploration of superficial lymph nodes. These have little value in diagnosing visceral CL, where the main sign is emaciation. The prevention and control of CL involve identifying the skin condition and debriding the abscesses. In addition to the treatment of superficial lesions, the animal facilities must be repaired and adapted. To avoid exposure of negative herds to CL, new animals must be subjected to observation to identify any of the clinical manifestations. Another form of control is vaccination, though only some countries have commercial vaccines. General information on the etiological agent and its characteristics can be used to improve the understanding of this disease.展开更多
YpsR,a pivotal regulatory protein in the quorum-sensing(QS)of Yersinia pseudotuberculosis(Y.pstb),is essential for molecular signaling,yet its molecular mechanisms remain poorly understood.Herein,this study systemati-...YpsR,a pivotal regulatory protein in the quorum-sensing(QS)of Yersinia pseudotuberculosis(Y.pstb),is essential for molecular signaling,yet its molecular mechanisms remain poorly understood.Herein,this study systemati-cally investigates the interactions between YpsR and acyl-homoserine lactones(AHLs),shedding light on the selective mechanism of YpsR to various AHL molecules.Using molecular docking and surface plasmon resonance(SPR)analysis,we confirmed YpsR’s binding affinities,with the strongest observed for 3OC6-HSL,which notably inhibited Y.pstb growth.Additionally,we engineered a whole-cell biosensor based on YpsR-AHL interaction,which exhibited sensitivity to the signal molecule 3OC6-HSL produced by Y.pstb.Furthermore,key YpsR resi-dues(S32,Y50,W54,D67)involved in AHL binding were identified and validated.Overall,this research elu-cidates the mechanisms of QS signal recognition in Y.pstb,providing valuable insights that support the development of diagnostic tools for detecting Y.pstb infections.展开更多
文摘【背景】硫氧还蛋白系统是细菌重要的氧化还原状态维持系统。假结核耶尔森氏菌(Yersinia pseudotuberculosis)YPⅢ是肠道常见的机会致病菌,在YPⅢ中进行过氧化氢胁迫下的转录组测序,结果发现硫氧还蛋白系统的相关基因有所上调,可能参与细菌氧化胁迫的应答。【目的】研究假结核耶尔森氏菌中硫氧还蛋白系统应答氧化胁迫的方式。【方法】利用同源重组方法构建硫氧还蛋白系统缺失突变株(ΔtrxA、ΔtrxC和ΔtrxR),研究假结核耶尔森氏菌在过氧化氢胁迫下的生长,测定过氧化氢对细菌的最低抑菌浓度、过氧化氢清除能力,以及过氧化氢处理下的存活率等。同时,通过lacZ报告基因系统对硫氧还蛋白系统的表达调控进行探究。【结果】构建硫氧还蛋白系统缺失突变株,发现缺失trxA后显著影响了假结核耶尔森氏菌的抗氧化胁迫能力,因此TrxA是硫氧还蛋白系统中应答氧化胁迫的主要蛋白;在ΔtrxA中过氧化氢酶的表达上调,但不足以保护细菌及时修复受损的生物大分子;启动子活性测定及实时荧光定量PCR(real time quantitative PCR,RT-qPCR)实验结果表明trxC和trxR的表达可能受到细菌氧化胁迫转录调控因子OxyR的影响。【结论】硫氧还蛋白系统作为细菌内部还原环境的维持系统,在OxyR的调控下参与氧化胁迫应答,并发挥了重要的作用。
文摘Objective:To investigate clinicopathological,bacteriological and pathological aspects of an experimental infection with Yersinia pseudotuberculosis(Y.pseudotuberculosis)in hares in order to verify the efficacy of serology for the in vivo diagnosis.Moreover,the pathogenicity of two Y.pseudotuberculosis strains was investigated in order to detect potential differences.Methods:Twelve European brown hares(Lepus europaeus,Pallas)were experimentally infected per os and via conjunctival mucosae with Y.pseudotuberculosis:six subjects were infected with a strain isolated from a naturally infected hare(YpH)and six subjects with a strain isolated from a naturally infected rabbit(YpR).Two hares were used as negative controls.All animals were subjected to clinical,bacteriological and serological examinations during 9 weeks following the infection and,at the end of the control period,subjects still alive were euthanized and submitted to a complete post mortem examination.Results:All faecal samples collected during the control period were positive for bacteriological examinations and to a PCR for the inv gene of Y.pseudotuberculosis,while only one Yp H-infected hare showed a positive haemocultures.From the 2nd to the 9th week post infection(pi),serological analysis revealed specific antibodies with titers ranging from 1:10 to 1:160 in all YpH-infected and two YpR-infected subjects.All the Yp H-infected and two Yp R-infected hares scored positive for Y.pseudotuberculosis by means of bacteriological investigations.Grossly,suppurative multifocal lesions were detected in liver,spleen,kidney and sub-mandibular lymph nodes in both YpH-and YpR-infected hares and confirmed with histopathology.Pulmonary lesions were observed only in Yp H-infected subjects.Immunohistochemistry confirmed the presence of bacterial antigen in all infected animals.Conclusion:Results of this study revealed that YpH strain is more pathogenic for hares than the YpR strain;moreover the serological test performed in this study could be used for the diagnosis of pseudotuberculosis in hares,whereas post mortem diagnosis should be confirmed by means of bacteriological examination,PCR,histopathology and immunohistochemistry.
文摘Corynebacterium pseudotuberculosis is an infectious agent that occurs in small ruminants causing caseous lymphadenitis, and more rarely in humans causing lymphadenitis and pneumonia. The breeding small ruminants have great economic importance in Brazil. Rural farm workers and veterinary students who acquired this disease suffered from weakening symptoms for weeks, and the identification of the etiological agent was time-consuming and complex. Due to the low prevalence of case records, there is probably no available commercial diagnostic kit for C. pseudotuberculosis infection in humans. This study aimed to describe human seroreactivity to secreted antigens from C. pseudotuberculosis. Reactivity of serum from farm workers (n = 14), individuals who work with the bacillus at laboratory (n = 8) or individuals without contact (n = 25) was tested with secreted proteins from PAT10 strain of C. pseudotuberculosis by Western blotting. Samples of all (100%) farm workers showed reactivity to 31 kDa, 71 kDa and 164 kDa proteins, while laboratory workers showed 87.5%, 62.5 % and 37.5%, and no-contact 20%, 0% and 16%, respectively. All sera recognized the 275 kDa protein. Our data suggest that C. pseudotuberculosis secreted proteins are antigenic in humans and the recognition profiles allowed the identification of individuals with and without prior contact with this bacillus. This is the first paper which describes human reactivity to C. pseudotuberculosis in serum samples of workers in Brazil.
文摘Caseous lymphadenitis (CL) is a chronic infectious disease caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) that is transmitted mainly by contact with contaminated exudate wounds. Caseous lymphadenitis affects different species of animals and is considered an occupational zoonotic disease. CL is responsible for important economic losses in the small ruminant industry, which include decreased production, damaged quality of milk and wool, reproductive disorders, total or partial confiscation of carcasses, and depreciation of the skin. Caseous lymphadenitis disease can present in two clinical pictures: a skin or superficial picture and a visceral or deep picture. The presumptive diagnosis of CL in the skin is based on the exploration of superficial lymph nodes. These have little value in diagnosing visceral CL, where the main sign is emaciation. The prevention and control of CL involve identifying the skin condition and debriding the abscesses. In addition to the treatment of superficial lesions, the animal facilities must be repaired and adapted. To avoid exposure of negative herds to CL, new animals must be subjected to observation to identify any of the clinical manifestations. Another form of control is vaccination, though only some countries have commercial vaccines. General information on the etiological agent and its characteristics can be used to improve the understanding of this disease.
基金the National Natural Science Foundation of China(32270813)Young Scientists Fund of the National Natural Science Foundation of China(22305173)Beijing Natural Science Foundation(5244033)for supporting this work.
文摘YpsR,a pivotal regulatory protein in the quorum-sensing(QS)of Yersinia pseudotuberculosis(Y.pstb),is essential for molecular signaling,yet its molecular mechanisms remain poorly understood.Herein,this study systemati-cally investigates the interactions between YpsR and acyl-homoserine lactones(AHLs),shedding light on the selective mechanism of YpsR to various AHL molecules.Using molecular docking and surface plasmon resonance(SPR)analysis,we confirmed YpsR’s binding affinities,with the strongest observed for 3OC6-HSL,which notably inhibited Y.pstb growth.Additionally,we engineered a whole-cell biosensor based on YpsR-AHL interaction,which exhibited sensitivity to the signal molecule 3OC6-HSL produced by Y.pstb.Furthermore,key YpsR resi-dues(S32,Y50,W54,D67)involved in AHL binding were identified and validated.Overall,this research elu-cidates the mechanisms of QS signal recognition in Y.pstb,providing valuable insights that support the development of diagnostic tools for detecting Y.pstb infections.
