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
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
The flagella master regulatory gene flhDC of Yersinia pseudotuberculosis serotype III (YPIII) was mutated by deleting the middle region; replaced by a tetracycline resistant gene,; the subsequent mutant strain named Y...The flagella master regulatory gene flhDC of Yersinia pseudotuberculosis serotype III (YPIII) was mutated by deleting the middle region; replaced by a tetracycline resistant gene,; the subsequent mutant strain named YPIIIΔflhDC was obtained. Swimming assay showed that the swimming motility of the mutant strain was completely abolished. The promoter region of the flagella second-class regulatory gene fliA was fused with the lux box,; was conjugated with the mutant; the parent strains respectively for the first cross. LUCY assay result demonstrated that flhDC regulated the expression of fliA in YPIII as reported in E. coli. Biofilm formation of the mutant strain on abiotic; biotic surfaces was observed; quantified. The results showed that mutation of flhDC decreased biofilm formation on both abiotic; biotic surfaces,; abated the infection on Caenorhabdtis elegans. Our results suggest that mutation of the flagella master regulatory gene flhDC not only abolished the swimming motility, but also affected biofilm formation of YPIII on different surfaces. The new function of flhDC identified in this study provides a novel viewpoint for the control of bacterial biofilm formation.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
Flea-borne transmission is a recent evolutionary adaptation that distinguishes the deadly Yersinia pestis from its progenitor Y.pseudotuberculosis,a mild pathogen transmitted via the food-borne route.Y.pestis synthesi...Flea-borne transmission is a recent evolutionary adaptation that distinguishes the deadly Yersinia pestis from its progenitor Y.pseudotuberculosis,a mild pathogen transmitted via the food-borne route.Y.pestis synthesizes biofilms in the flea gut,which is important for fleaborne transmission.Yersinia biofilms are bacterial colonies surrounded by extracellular matrix primarily containing a homopolymer of N-acetyl-D-glucosamine that are synthesized by a set of specific enzymes.Yersinia biofilm production is tightly regulated at both transcriptional and post-transcriptional levels.All the known structural genes responsible for biofilm production are harbored in both Y.pseudotuberculosis and Y.pestis,but Y.pestis has evolved changes in the regulation of biofilm development,thereby acquiring efficient arthropod-borne transmission.展开更多
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.
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.
基金Supported by the National Natural Science Foundation of China (Grant No. 30570020)
文摘The flagella master regulatory gene flhDC of Yersinia pseudotuberculosis serotype III (YPIII) was mutated by deleting the middle region; replaced by a tetracycline resistant gene,; the subsequent mutant strain named YPIIIΔflhDC was obtained. Swimming assay showed that the swimming motility of the mutant strain was completely abolished. The promoter region of the flagella second-class regulatory gene fliA was fused with the lux box,; was conjugated with the mutant; the parent strains respectively for the first cross. LUCY assay result demonstrated that flhDC regulated the expression of fliA in YPIII as reported in E. coli. Biofilm formation of the mutant strain on abiotic; biotic surfaces was observed; quantified. The results showed that mutation of flhDC decreased biofilm formation on both abiotic; biotic surfaces,; abated the infection on Caenorhabdtis elegans. Our results suggest that mutation of the flagella master regulatory gene flhDC not only abolished the swimming motility, but also affected biofilm formation of YPIII on different surfaces. The new function of flhDC identified in this study provides a novel viewpoint for the control of bacterial biofilm formation.
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(Grant Nos.30930001,30900823,and 30771179)the National Basic Research Program(973 Program)(Grant No.2009CB522600)。
文摘Flea-borne transmission is a recent evolutionary adaptation that distinguishes the deadly Yersinia pestis from its progenitor Y.pseudotuberculosis,a mild pathogen transmitted via the food-borne route.Y.pestis synthesizes biofilms in the flea gut,which is important for fleaborne transmission.Yersinia biofilms are bacterial colonies surrounded by extracellular matrix primarily containing a homopolymer of N-acetyl-D-glucosamine that are synthesized by a set of specific enzymes.Yersinia biofilm production is tightly regulated at both transcriptional and post-transcriptional levels.All the known structural genes responsible for biofilm production are harbored in both Y.pseudotuberculosis and Y.pestis,but Y.pestis has evolved changes in the regulation of biofilm development,thereby acquiring efficient arthropod-borne transmission.
