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He Q, Zheng Y, Yan K, Tang J, Yang F, Tian Y, Yang L, Dou B, Chen Y, Gu J, Chen H, Yuan F, Bei W. The cAMP receptor protein gene contributes to growth, stress resistance, and colonization of Actinobacillus pleuropneumoniae. Vet Microbiol 2024; 290:110006. [PMID: 38308931 DOI: 10.1016/j.vetmic.2024.110006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 02/05/2024]
Abstract
Porcine infectious pleuropneumonia (PCP) is a severe disease of porcine caused by Actinobacillus pleuropneumoniae (APP). The spread of PCP remains a threat to the porcine farms and has been known to cause severe economic losses. The cAMP receptor protein (CRP) serves as a pivotal player in helping bacteria adapt to shifts in their environment, particularly when facing the challenges posed by bacterial infections. In this study, we investigated the role of CRP in APP. Our results revealed that crp mutant (Δcrp) strains were more sensitive to acidic and osmotic stress resistance and had lower biofilm formation ability than wild-type (WT) strains. Furthermore, the Δcrp strains showed deficiencies in anti-phagocytosis, adhesion, and invasion upon interaction with host cells. Mice infected with the Δcrp strains demonstrated reduced bacterial loads in their lungs compared to those infected with the WT strains. This study reveals the pivotal role of crp gene expression in regulating pleuropneumonia growth, stress resistance, iron utilization, biofilm formation, phagocytosis, adhesion, invasion and colonization. Our discoveries offer novel perspectives on understanding the development and progression of APP infections.
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Affiliation(s)
- Qiyun He
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Yaxuan Zheng
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Kang Yan
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Jia Tang
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Fengming Yang
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Yanhong Tian
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Lijun Yang
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Beibei Dou
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Yunpeng Chen
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Jun Gu
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Fangyan Yuan
- Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Weicheng Bei
- National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China.
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Soto Perezchica MM, Guerrero Barrera AL, Avelar Gonzalez FJ, Quezada Tristan T, Macias Marin O. Actinobacillus pleuropneumoniae, surface proteins and virulence: a review. Front Vet Sci 2023; 10:1276712. [PMID: 38098987 PMCID: PMC10720984 DOI: 10.3389/fvets.2023.1276712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 10/17/2023] [Indexed: 12/17/2023] Open
Abstract
Actinobacillus pleuropneumoniae (App) is a globally distributed Gram-negative bacterium that produces porcine pleuropneumonia. This highly contagious disease produces high morbidity and mortality in the swine industry. However, no effective vaccine exists to prevent it. The infection caused by App provokes characteristic lesions, such as edema, inflammation, hemorrhage, and necrosis, that involve different virulence factors. The colonization and invasion of host surfaces involved structures and proteins such as outer membrane vesicles (OMVs), pili, flagella, adhesins, outer membrane proteins (OMPs), also participates proteases, autotransporters, and lipoproteins. The recent findings on surface structures and proteins described in this review highlight them as potential immunogens for vaccine development.
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Affiliation(s)
- María M. Soto Perezchica
- Laboratorio de Biología Celular y Tisular, Departamento de Morfología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Alma L. Guerrero Barrera
- Laboratorio de Biología Celular y Tisular, Departamento de Morfología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Francisco J. Avelar Gonzalez
- Laboratorio de Estudios Ambientales, Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Teodulo Quezada Tristan
- Departamento de Ciencias Veterinaria, Centro de Ciencias Agropecuarias, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Osvaldo Macias Marin
- Laboratorio de Biología Celular y Tisular, Departamento de Morfología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
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Duan B, Peng W, Yan K, Liu F, Tang J, Yang F, Chen H, Yuan F, Bei W. The QseB/QseC two-component system contributes to virulence of Actinobacillus pleuropneumoniae by downregulating apf gene cluster transcription. ANIMAL DISEASES 2022. [DOI: 10.1186/s44149-022-00036-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractActinobacillus pleuropneumoniae (APP) is the major pathogen of porcine contagious pleuropneumoniae (PCP). The QseB/QseC two-component system (TCS) consists of the regulator QseB and the kinase QseC, which relates to quorum sensing (QS) and virulence in some bacteria. Here, we investigated the role of QseB/QseC in apf gene cluster (apfABCD) expression of APP. Our results have showed that QseB/QseC TCS can potentially regulate the expression of apf gene cluster. The ΔqseBC, ΔapfA, ΔapfB, ΔapfC and ΔapfD strains are more sensitive to acidic and osmotic stressful conditions, and exhibite lower biofilm formation ability than wild-type (WT) strain, whereas the complemented strains show similar phenotype to the WT strain. In additon, the mutants have defective anti-phagocytosis, adhesion and invasion when they come into contact with the host cells. In experimental animal models of infection, mice infected with ΔqseBC, ΔapfA, ΔapfB, ΔapfC and ΔapfD strains showed lower mortality and bacterial loads in the lung and the blood than those infected with WT strain. In conclusion, our results suggest that QseB/QseC TCS contributes to stress resistance, biofilm formation, phagocytosis, adhesion, invasion and virulence by downregulating expression of apf gene cluster in A. pleuropneumoniae.
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Identification of FtpA, a Dps-like protein involved in anti-oxidative stress and virulence in Actinobacillus pleuropneumoniae. J Bacteriol 2021; 204:e0032621. [PMID: 34807725 DOI: 10.1128/jb.00326-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria have evolved a variety of enzymes to eliminate endogenous or host-derived oxidative stress factors. The Dps protein, first identified in Escherichia coli, contains a ferroxidase center and protects bacteria from reactive oxygen species damage. There is a lack of knowledge of the role of Dps-like proteins in bacterial pathogenesis. Actinobacillus pleuropneumoniae causes pleuropneumonia, a respiratory disease of swine. The A. pleuropneumoniae ftpA gene is up-regulated during a shift to anaerobiosis, in biofilms and, as found in this study, also by H2O2. An A. pleuropneumoniae ftpA deletion mutant (△ftpA) had increased H2O2 sensitivity, less intracellular viability in macrophages, and decreased virulence in a mouse infection model. Expression of ftpA in an E. coli dps mutant restored wild-type resistance to H2O2. FtpA possesses a conserved ferritin domain containing a ferroxidase site. Recombinant rFtpA bound and oxidized Fe2+ reversibly. Under aerobic conditions, compared with the wild-type strain, the viability of an △ftpA mutant was reduced after extended culture, transition from anaerobic to aerobic conditions, and upon supplementation with Fenton reaction substrates. Under anaerobic conditions, additional H2O2 resulted in a more severe growth defect of △ftpA than under aerobic conditions. Therefore, by oxidizing and mineralizing Fe2+, FtpA alleviates oxidative damage mediated by intracellular Fenton reactions. Furthermore, by mutational analysis, two residues were confirmed to be critical for Fe2+ binding and oxidization, as well as for A. pleuropneumoniae H2O2 resistance. Taken together, this study demonstrates that A. pleuropneumoniae FtpA is a Dps-like protein, playing critical roles in oxidative stress resistance and virulence. IMPORTANCE As a ferroxidase, Dps of Escherichia coli can protect bacteria from reactive oxygen species damage, but its role in bacterial pathogenesis has received little attention. In this study, FtpA of the swine respiratory pathogen A. pleuropneumoniae was identified as a new Dps-like protein. It facilitated A. pleuropneumoniae resistance to H2O2, survival in macrophages, and infection in vivo. FtpA could bind and oxidize Fe2+ through two important residues in its ferroxidase site and protected the bacteria from oxidative damage mediated by the intracellular Fenton reaction. These findings provide new insights into the role of the FtpA-based antioxidant system in the pathogenesis of A. pleuropneumoniae, and the conserved Fe2+ binding ligands in Dps/FtpA provide novel drug target candidates for disease prevention.
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Nahar N, Turni C, Tram G, Blackall PJ, Atack JM. Actinobacillus pleuropneumoniae: The molecular determinants of virulence and pathogenesis. Adv Microb Physiol 2021; 78:179-216. [PMID: 34147185 DOI: 10.1016/bs.ampbs.2020.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, is responsible for high economic losses in swine herds across the globe. Pleuropneumonia is characterized by severe respiratory distress and high mortality. The knowledge about the interaction between bacterium and host within the porcine respiratory tract has improved significantly in recent years. A. pleuropneumoniae expresses multiple virulence factors, which are required for colonization, immune clearance, and tissue damage. Although vaccines are used to protect swine herds against A. pleuropneumoniae infection, they do not offer complete coverage, and often only protect against the serovar, or serovars, used to prepare the vaccine. This review will summarize the role of individual A. pleuropneumoniae virulence factors that are required during key stages of pathogenesis and disease progression, and highlight progress made toward developing effective and broadly protective vaccines against an organism of great importance to global agriculture and food production.
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Affiliation(s)
- Nusrat Nahar
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Conny Turni
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia
| | - Greg Tram
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Patrick J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia.
| | - John M Atack
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia.
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Antenucci F, Ovsepian A, Wrobel A, Winther-Larsen HC, Bojesen AM. Design and Characterization of a Novel Tool for the Antigenic Enrichment of Actinobacillus pleuropneumoniae Outer Membrane. Pathogens 2020; 9:E1014. [PMID: 33276526 PMCID: PMC7761619 DOI: 10.3390/pathogens9121014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 11/30/2020] [Accepted: 11/30/2020] [Indexed: 02/06/2023] Open
Abstract
Production and isolation of recombinant proteins are costly and work-intensive processes, especially in immunology when tens or hundreds of potential immunogens need to be purified for testing. Here we propose an alternative method for fast screening of immunogen candidates, based on genetic engineering of recombinant bacterial strains able to express and expose selected antigens on their outer membrane. In Actinobacillus pleuropneumoniae, a Gram-negative porcine pathogen responsible for extensive economic losses worldwide, we identified a conserved general secretion pathway (GSP) domain in the N-terminal part of the outer membrane protein ApfA (ApfA stem: ApfAs). ApfAs was used as an outer membrane anchor, to which potential immunogens can be attached. To enable confirmation of correct positioning, ApfAs, was cloned in combination with the modified acyl carrier protein (ACP) fluorescent tag ACP mini (ACPm) and the putative immunogen VacJ. The chimeric construct was inserted in the pMK-express vector, subsequently transformed into A. pleuropneumoniae for expression. Flow cytometry, fluorescence imaging and mass spectrometry analysis were employed to demonstrate that the outer membrane of the transformed strain was enriched with the chimeric ApfAs-ACPm-VacJ antigen. Our results confirmed correct positioning of the chimeric ApfAs-ACPm-VacJ antigen and supported this system's potential as platform technology enabling antigenic enrichment of the outer membrane of A. pleuropneumoniae.
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Affiliation(s)
- Fabio Antenucci
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Copenhagen, Denmark; (F.A.); (A.O.)
| | - Armen Ovsepian
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Copenhagen, Denmark; (F.A.); (A.O.)
| | - Agnieszka Wrobel
- Section of Pharmaceutical Biosciences, Centre of Integrative Microbial Evolution, Department of Pharmacy, University of Oslo, Sem Sælandsvei 3, 0316 Oslo, Norway; (A.W.); (H.C.W.-L.)
| | - Hanne Cecilie Winther-Larsen
- Section of Pharmaceutical Biosciences, Centre of Integrative Microbial Evolution, Department of Pharmacy, University of Oslo, Sem Sælandsvei 3, 0316 Oslo, Norway; (A.W.); (H.C.W.-L.)
| | - Anders Miki Bojesen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Copenhagen, Denmark; (F.A.); (A.O.)
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Nath S, Sikidar J, Roy M, Deb B. In vitro screening of probiotic properties of Lactobacillus plantarum isolated from fermented milk product. FOOD QUALITY AND SAFETY 2020. [DOI: 10.1093/fqsafe/fyaa026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Objectives
The screening of traditional fermented products is essential for the assessment of safety, security, and further development of functional foods for the well-being of human health. The aim of the present study was to isolate and identify bacteria from fermented raw milk samples that exhibit health benefits upon consumption.
Methods
In order to confirm the isolates as probiotics, several in vitro assays were conducted to assess the probiotic properties of isolated bacteria. The initial screening includes tolerance to acid, bile, pancreatin, and NaCl. The cell surface properties demonstrate their interaction with mucosal epithelium, which includes hydrophobicity and auto-aggregation assay. Safety assessment was done by performing haemolytic test and antibiotic susceptibility test. The antagonistic activity of probiotic strain was further evaluated against some pathogenic bacteria.
Results
Lactobacillus plantarum (L. plantarum) isolated from fermented raw milk was preliminarily identified by biochemical tests and further confirmed using 16S rRNA identification. The isolate designated as L. plantarum strain GCC_19M1 demonstrated significant tolerance to low pH, 0.3% bile, 0.5% pancreatin, and 5% NaCl. In the presence of simulated gastric juice (at pH 3), the isolate exhibited a survival rate of 93.48–96.97%. Furthermore, the development of ecological niches in the human gut and their successful accumulation have been revealed by auto-aggregation and hydrophobicity properties. Absence of haemolytic activity ensures the non-virulent nature of the strain. Lactobacillus plantarum strain GCC_19M1 showed susceptibility towards gentamicin, tetracycline, kanamycin, meropenem, and ceftriaxone and exhibited an antagonistic effect on pathogenic bacteria.
Conclusion
The obtained results conveyed that L. plantarum strain GCC_19M1 has strong probiotic potential, and its presence in the fermented raw milk products may serve as a potent functional probiotic food.
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Affiliation(s)
- Soumitra Nath
- Department of Biotechnology, Gurucharan College, Silchar, India
- Institutional Biotech Hub, Gurucharan College, Silchar, India
| | - Jibalok Sikidar
- Department of Biotechnology, Gurucharan College, Silchar, India
| | - Monisha Roy
- Department of Biotechnology, Gurucharan College, Silchar, India
| | - Bibhas Deb
- Department of Biotechnology, Gurucharan College, Silchar, India
- Institutional Biotech Hub, Gurucharan College, Silchar, India
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Xiao J, Liu J, Bao C, Zhu R, Gu J, Sun C, Feng X, Du C, Han W, Li Y, Lei L. Recombinant tandem epitope vaccination provides cross protection against Actinobacillus pleuropneumoniae challenge in mice. AMB Express 2020; 10:123. [PMID: 32642871 PMCID: PMC7341470 DOI: 10.1186/s13568-020-01051-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/15/2020] [Indexed: 11/10/2022] Open
Abstract
Actinobacillus pleuropneumoniae (A. pleuropneumoniae/APP) is the pathogen that causes porcine contagious pleuropneumonia. Actinobacillus pleuropneumoniae is divided into 18 serovars, and the cross protection efficacy of epitopes is debatable, which has resulted in the slow development of a vaccine. Consequently, epitope-based vaccines conferring Actinobacillus pleuropneumoniae cross protection have rarely been reported. In this study, B cell epitopes in the head domain of trimeric autotransporter adhesin were predicted, and 6 epitopes were selected. Then, the predicted epitopes (Ba1, Bb5, C1, PH1 and PH2) were connected by linkers to construct a recombinant tandem antigen (rta) gene. The RTA protein encoded by the recombinant rta gene was expressed, and finally the ICR mice were immunized with the RTA protein with or without inactivated Actinobacillus pleuropneumoniae (serovars 1 and 5b) and challenged with Actinobacillus pleuropneumoniae to evaluate the protective effect of the epitope-based vaccine and combined vaccine. The mice in the RTA-immunized group and RTA plus inactivated Actinobacillus pleuropneumoniae vaccine group had a significant improvement in clinical symptoms and a higher level of antibody in the serum than those in the control group. The RTA immune group had a 40% survival rate after Actinobacillus pleuropneumoniae infection, whereas the combination of RTA and inactivated Actinobacillus pleuropneumoniae produced very strong cross immune protection in mice, at least 50% (RTA IB1 + C5) and at most 100% (RTA IB5 + C1), whereas no cross immunoprotection was found in the solo Actinobacillus pleuropneumoniae immune group. Overall, the combination of the RTA protein and inactivated bacteria significantly enhanced the cross protection effects. This implies that RTA protein in combination with a suitable inactivated Actinobacillus pleuropneumoniae strain could be a candidate vaccine for porcine contagious pleuropneumonia.
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Li T, Zhang Q, Wang R, Zhang S, Pei J, Li Y, Li L, Zhou R. The roles of flp1 and tadD in Actinobacillus pleuropneumoniae pilus biosynthesis and pathogenicity. Microb Pathog 2019; 126:310-317. [DOI: 10.1016/j.micpath.2018.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 11/02/2018] [Accepted: 11/05/2018] [Indexed: 01/07/2023]
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Liu F, Peng W, Liu T, Zhao H, Yan K, Yuan F, Chen H, Bei W. Biological role of Actinobacillus pleuropneumoniae type IV pilus proteins encoded by the apf and pil operons. Vet Microbiol 2018; 224:17-22. [DOI: 10.1016/j.vetmic.2018.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 12/16/2022]
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Liu J, Cao Y, Gao L, Zhang L, Gong S, Yang J, Zhao H, Yang D, Zhao J, Meng J, Gao Q, Qi C. Outer Membrane Lipoprotein Lip40 Modulates Adherence, Colonization, and Virulence of Actinobacillus pleuropneumoniae. Front Microbiol 2018; 9:1472. [PMID: 30018613 PMCID: PMC6038445 DOI: 10.3389/fmicb.2018.01472] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 06/13/2018] [Indexed: 12/13/2022] Open
Abstract
Bacterial lipoproteins are a set of membrane proteins with various functions; many of which are virulence factors of pathogenic bacteria. In the present study, we investigated the role of an outer membrane lipoprotein Lip40 in the pathogenesis of Actinobacillus pleuropneumoniae. A mutant strain (Δlip40) lacking Lip40 and a complemented strain (CΔlip40) were constructed. Δlip40 exhibited reduced adherence to the St. Jude porcine lung cells. The ability of the Δlip40 mutant to colonize the mouse lung tissues was significantly impaired compared to that of the wild type and complementation strains. Furthermore, an infection assay revealed that pigs infected with Δlip40 showed fewer clinical signs and lung lesions, indicating that Lip40 contributed to the development of porcine pleuropneumonia. Collectively, our data suggest that Lip40 is involved in the virulence of A. pleuropneumoniae.
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Affiliation(s)
- Jinlin Liu
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Yurou Cao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Lulu Gao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Li Zhang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Siying Gong
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Jihong Yang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Haobin Zhao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Dengfu Yang
- Lichuan Municipal Bureau of Animal Husbandry and Veterinary Medicine, Lichuan, China
| | - Jin Zhao
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Jianzhong Meng
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
| | - Qishuang Gao
- Department of Animal Biotechnology and Cell Engineering, Wuhan Institute of Animal Husbandry and Veterinary Sciences, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Chao Qi
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, China
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Yuan F, Liu J, You W, Bei W, Wang C, Zhao J, Tian Y, Liu S. Generation, safety and immunogenicity of an Actinobacillus pleuropneumoniae quintuple deletion mutant SLW07 (ΔapxICΔapxIICΔorf1ΔcpxARΔarcA). Vaccine 2018; 36:1830-1836. [PMID: 29486946 DOI: 10.1016/j.vaccine.2018.02.083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 02/05/2018] [Accepted: 02/19/2018] [Indexed: 10/18/2022]
Abstract
We inactivated a virulence determinant, ArcA, in an Actinobacillus pleuropneumoniae quadruple deletion mutant SLW06 (ΔapxICΔapxIICΔorf1ΔcpxAR, serovar 1), and a quintuple deletion mutant SLW07 was generated. SLW07 showed decreased adherence to and invasion of host cells, compared to its parent strain SLW06. SLW07 was more sensitive in RAW264.7 macrophage-mediated phagocytosis and clearance. SLW07 was less virulent in mice. An immunization assay indicated that both SLW07 and SLW06 preferentially stimulated T helper cell type 2 response in mice. Live vaccines induced the production of interleukin-6 and tumor necrosis factor-α by splenic lymphocytes. Furthermore, the protective immunity of SLW07 was not affected after ArcA mutation. Immunization with SLW07 could provide a complete protection following virulent A. pleuropneumoniae challenge in mice. Our results suggest that SLW07 is a promising live vaccine candidate, which is further attenuated from and shares similar protective efficacy with its quadruple deletion parent SLW06.
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Affiliation(s)
- Fangyan Yuan
- Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Wuhan, Hubei 430064, China
| | - Jinlin Liu
- College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China
| | - Wujin You
- State Key Laboratory of Agricultural Microbiology, The Cooperative Innovation Center for Sustainable Pig Production, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology, The Cooperative Innovation Center for Sustainable Pig Production, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Chunlai Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Jin Zhao
- College of Life Sciences, Central China Normal University, Wuhan, Hubei 430079, China
| | - Yiongxiang Tian
- Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Wuhan, Hubei 430064, China.
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China.
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Antenucci F, Fougeroux C, Deeney A, Ørskov C, Rycroft A, Holst PJ, Bojesen AM. In vivo testing of novel vaccine prototypes against Actinobacillus pleuropneumoniae. Vet Res 2018; 49:4. [PMID: 29316978 PMCID: PMC5761136 DOI: 10.1186/s13567-017-0502-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/18/2017] [Indexed: 02/05/2023] Open
Abstract
Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is a Gram-negative bacterium that represents the main cause of porcine pleuropneumonia in pigs, causing significant economic losses to the livestock industry worldwide. A. pleuropneumoniae, as the majority of Gram-negative bacteria, excrete vesicles from its outer membrane (OM), accordingly defined as outer membrane vesicles (OMVs). Thanks to their antigenic similarity to the OM, OMVs have emerged as a promising tool in vaccinology. In this study we describe the in vivo testing of several vaccine prototypes for the prevention of infection by all known A. pleuropneumoniae serotypes. Previously identified vaccine candidates, the recombinant proteins ApfA and VacJ, administered individually or in various combinations with the OMVs, were employed as vaccination strategies. Our data show that the addition of the OMVs in the vaccine formulations significantly increased the specific IgG titer against both ApfA and VacJ in the immunized animals, confirming the previously postulated potential of the OMVs as adjuvant. Unfortunately, the antibody response raised did not translate into an effective protection against A. pleuropneumoniae infection, as none of the immunized groups following challenge showed a significantly lower degree of lesions than the controls. Interestingly, quite the opposite was true, as the animals with the highest IgG titers were also the ones bearing the most extensive lesions in their lungs. These results shed new light on A. pleuropneumoniae pathogenicity, suggesting that antibody-mediated cytotoxicity from the host immune response may play a central role in the development of the lesions typically associated with A. pleuropneumoniae infections.
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Affiliation(s)
- Fabio Antenucci
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, Copenhagen, Denmark
| | - Cyrielle Fougeroux
- Department of International Health, Immunology and Microbiology ISIM, University of Copenhagen, Øster Farigmagsgade 5, Bldg 22/23, 1014 København K, Copenhagen, Denmark
| | - Alannah Deeney
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire, AL9 7TA, UK
| | - Cathrine Ørskov
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 København N, 12.3, Building: 32, Copenhagen, Denmark
| | - Andrew Rycroft
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire, AL9 7TA, UK
| | - Peter Johannes Holst
- Department of International Health, Immunology and Microbiology ISIM, University of Copenhagen, Øster Farigmagsgade 5, Bldg 22/23, 1014 København K, Copenhagen, Denmark
| | - Anders Miki Bojesen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, Copenhagen, Denmark.
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Antenucci F, Fougeroux C, Bossé JT, Magnowska Z, Roesch C, Langford P, Holst PJ, Bojesen AM. Identification and characterization of serovar-independent immunogens in Actinobacillus pleuropneumoniae. Vet Res 2017; 48:74. [PMID: 29122004 PMCID: PMC5679336 DOI: 10.1186/s13567-017-0479-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/20/2017] [Indexed: 11/17/2022] Open
Abstract
Despite numerous actions to prevent disease, Actinobacillus pleuropneumoniae (A. pleuropneumoniae) remains a major cause of porcine pleuropneumonia, resulting in economic losses to the swine industry worldwide. In this paper, we describe the utilization of a reverse vaccinology approach for the selection and in vitro testing of serovar-independent A. pleuropneumoniae immunogens. Potential immunogens were identified in the complete genomes of three A. pleuropneumoniae strains belonging to different serovars using the following parameters: predicted outer-membrane subcellular localization; ≤ 1 trans-membrane helices; presence of a signal peptide in the protein sequence; presence in all known A. pleuropneumoniae genomes; homology with other well characterized factors with relevant data regarding immunogenicity/protective potential. Using this approach, we selected the proteins ApfA and VacJ to be expressed and further characterized, both in silico and in vitro. Additionally, we analysed outer membrane vesicles (OMVs) of A. pleuropneumoniae MIDG2331 as potential immunogens, and compared deletions in degS and nlpI for increasing yields of OMVs compared to the parental strain. Our results indicated that ApfA and VacJ are highly conserved proteins, naturally expressed during infection by all A. pleuropneumoniae serovars tested. Furthermore, OMVs, ApfA and VacJ were shown to possess a high immunogenic potential in vitro. These findings favour the immunogen selection protocol used, and suggest that OMVs, along with ApfA and VacJ, could represent effective immunogens for the prevention of A. pleuropneumoniae infections in a serovar-independent manner. This hypothesis is nonetheless predictive in nature, and in vivo testing in a relevant animal model will be necessary to verify its validity.
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Affiliation(s)
- Fabio Antenucci
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, Copenhagen, Denmark
| | - Cyrielle Fougeroux
- Department of International Health, Immunology and Microbiology ISIM, University of Copenhagen, Øster Farigmagsgade 5, Bldg 22/23, København K, 1014, Copenhagen, Denmark
| | - Janine T Bossé
- Department of Medicine, St Mary's Campus, Imperial College London, 236 Wright Fleming Wing, London, UK
| | - Zofia Magnowska
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, Copenhagen, Denmark
| | - Camille Roesch
- Izon Science Ltd, Bâtiment Laennec, 60 Avenue Rockefeller, 69008, Lyon, France
| | - Paul Langford
- Department of Medicine, St Mary's Campus, Imperial College London, 236 Wright Fleming Wing, London, UK
| | - Peter Johannes Holst
- Department of International Health, Immunology and Microbiology ISIM, University of Copenhagen, Øster Farigmagsgade 5, Bldg 22/23, København K, 1014, Copenhagen, Denmark
| | - Anders Miki Bojesen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frb. C., 1-20, Building: 301, Copenhagen, Denmark.
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Hu X, Yan H, Liu K, Hu J, Qi C, Yang J, Liu Y, Zhao J, Liu J. Identification and characterization of a novel stress-responsive outer membrane protein Lip40 from Actinobacillus pleuropneumoniae. BMC Biotechnol 2015; 15:106. [PMID: 26608465 PMCID: PMC4660844 DOI: 10.1186/s12896-015-0199-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/29/2015] [Indexed: 01/30/2023] Open
Abstract
Background Actinobacillus pleuropneumoniae, a Gram-negative bacterium, is the causative agent of porcine pleuropneumonia, a highly contagious and often fatal disease. Because current vaccines confer limited protection against A. pleuropneumoniae infection, the development of more effective vaccines is urgently required. The identification of immunogenic and protective antigens, such as an outer-membrane lipoprotein, will advance this purpose. Results Sixty putative lipoproteins were predicted from the genomic sequence of A. pleuropneumoniae using multiple algorithms. Here, we focused on the characteristics of the putative lipoprotein Lip40 from A. pleuropneumoniae strain SLW01 (serovar 1). Lip40 shares sequence similarity with many bacterial lipoproteins, and the structural prediction of Lip40 suggests that it is similar to A. pleuropneumoniae TbpB. The N-terminus of Lip40 contains an interesting tandemly repeated sequence, Q(E/D/P)QPK. Real-time RT–PCR indicated that the expression of lip40 was significantly upregulated at 42 °C, at 16 °C, and under anaerobic conditions. Recombinant Lip40 (rLip40) produced in Escherichia coli BL21(DE3) was specifically recognized by porcine convalescent serum directed against A. pleuropneumoniae. Lip40 was confirmed to localize at the bacterial outer membrane, and its expression was significantly stimulated when A. pleuropneumoniae was cultured under various stress conditions. Lip40 also protected 75 % of mice from fatal virulent A. pleuropneumoniae infection. Conclusions The immunogenic outer-membrane protein Lip40 is stress responsive, protects mice against infection, and might be a virulence determinant. Further investigation of Lip40 should expedite vaccine development and provide insight into the pathogenesis of A. pleuropneumoniae. Electronic supplementary material The online version of this article (doi:10.1186/s12896-015-0199-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xuehe Hu
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Hao Yan
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Ke Liu
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Jiansheng Hu
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Chao Qi
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Jihong Yang
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Yanli Liu
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Jin Zhao
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
| | - Jinlin Liu
- College of Life Sciences, Central China Normal University, Wuhan, Hubei, 430079, China.
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Bujold AR, MacInnes JI. Identification of putative adhesins of Actinobacillus suis and their homologues in other members of the family Pasteurellaceae. BMC Res Notes 2015; 8:675. [PMID: 26567540 PMCID: PMC4644294 DOI: 10.1186/s13104-015-1659-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/02/2015] [Indexed: 12/03/2022] Open
Abstract
Background Actinobacillus suis disease has been reported in a wide range of vertebrate species, but is most commonly found in swine. A. suis is a commensal of the tonsils of the soft palate of swine, but in the presence of unknown stimuli it can invade the bloodstream, causing septicaemia and sequelae such as meningitis, arthritis, and death. It is genotypically and phenotypically similar to A. pleuropneumoniae, the causative agent of pleuropneumonia, and to other members of the family Pasteurellaceae that colonise tonsils. At present, very little is known about the genes involved in attachment, colonisation, and invasion by A. suis (or related members of the tonsil microbiota). Results Bioinformatic analyses of the A. suis H91-0380 genome were done using BASys and blastx in GenBank. Forty-seven putative adhesin-associated genes predicted to encode 24 putative adhesins were discovered. Among these are 6 autotransporters, 25 fimbriae-associated genes (encoding 3 adhesins), 12 outer membrane proteins, and 4 additional genes (encoding 3 adhesins). With the exception of 2 autotransporter-encoding genes (aidA and ycgV), both with described roles in virulence in other species, all of the putative adhesin-associated genes had homologues in A. pleuropneumoniae. However, the majority of the closest homologues of the A. suis adhesins are found in A. ureae and A. capsulatus—species not known to infect swine, but both of which can cause systemic infections. Conclusions A. suis and A. pleuropneumoniae share many of the same putative adhesins, suggesting that the different diseases, tissue tropism, and host range of these pathogens are due to subtle genetic differences, or perhaps differential expression of virulence factors during infection. However, many of the putative adhesins of A. suis share even greater homology with those of other pathogens within the family Pasteurellaceae. Similar to A. suis, these pathogens (A. capsulatus and A. ureae) cause systemic infections and it is tempting to speculate that they employ similar strategies to invade the host, but more work is needed before that assertion can be made. This work begins to examine adhesin-associated factors that allow some members of the family Pasteurellaceae to invade the bloodstream while others cause a more localised infection. Electronic supplementary material The online version of this article (doi:10.1186/s13104-015-1659-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adina R Bujold
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Ontario, N1G 2W1, Canada.
| | - Janet I MacInnes
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Ontario, N1G 2W1, Canada.
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Li G, Xie F, Zhang Y, Bossé JT, Langford PR, Wang C. Role of (p)ppGpp in Viability and Biofilm Formation of Actinobacillus pleuropneumoniae S8. PLoS One 2015; 10:e0141501. [PMID: 26509499 PMCID: PMC4624843 DOI: 10.1371/journal.pone.0141501] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/08/2015] [Indexed: 12/04/2022] Open
Abstract
Actinobacillus pleuropneumoniae is a Gram-negative bacterium and the cause of porcine pleuropneumonia. When the bacterium encounters nutritional starvation, the relA-dependent (p)ppGpp-mediated stringent response is activated. The modified nucleotides guanosine 5’-diphosphate 3’-diphosphate (ppGpp) and guanosine 5’-triphosphate 3’-diphosphate (pppGpp) are known to be signaling molecules in other prokaryotes. Here, to investigate the role of (p)ppGpp in A. pleuropneumoniae, we created a mutant A. pleuropneumoniae strain, S8ΔrelA, which lacks the (p)ppGpp-synthesizing enzyme RelA, and investigated its phenotype in vitro. S8ΔrelA did not survive after stationary phase (starvation condition) and grew exclusively as non-extended cells. Compared to the wild-type (WT) strain, the S8ΔrelA mutant had an increased ability to form a biofilm. Transcriptional profiles of early stationary phase cultures revealed that a total of 405 bacterial genes were differentially expressed (including 380 up-regulated and 25 down-regulated genes) in S8ΔrelA as compared with the WT strain. Most of the up-regulated genes are involved in ribosomal structure and biogenesis, amino acid transport and metabolism, translation cell wall/membrane/envelope biogenesis. The data indicate that (p)ppGpp coordinates the growth, viability, morphology, biofilm formation and metabolic ability of A. pleuropneumoniae in starvation conditions. Furthermore, S8ΔrelA could not use certain sugars nor produce urease which has been associated with the virulence of A. pleuropneumoniae, suggesting that (p)ppGpp may directly or indirectly affect the pathogenesis of A. pleuropneumoniae during the infection process. In summary, (p)ppGpp signaling represents an essential component of the regulatory network governing stress adaptation and virulence in A. pleuropneumoniae.
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Affiliation(s)
- Gang Li
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Fang Xie
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yanhe Zhang
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Janine T. Bossé
- Section of Paediatrics, Department of Medicine, Imperial College London, St. Mary’s Campus, London, United Kingdom
| | - Paul R. Langford
- Section of Paediatrics, Department of Medicine, Imperial College London, St. Mary’s Campus, London, United Kingdom
| | - Chunlai Wang
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
- * E-mail:
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18
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Zhou Y, Wang Y, Deng L, Zheng C, Yuan F, Chen H, Bei W, Li J. Evaluation of the protective efficacy of four novel identified membrane associated proteins of Streptococcus suis serotype 2. Vaccine 2015; 33:2254-2260. [DOI: 10.1016/j.vaccine.2015.03.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 02/20/2015] [Accepted: 03/12/2015] [Indexed: 12/11/2022]
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The Adh adhesin domain is required for trimeric autotransporter Apa1-mediated Actinobacillus pleuropneumoniae adhesion, autoaggregation, biofilm formation and pathogenicity. Vet Microbiol 2015; 177:175-83. [DOI: 10.1016/j.vetmic.2015.02.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 02/18/2015] [Accepted: 02/21/2015] [Indexed: 11/24/2022]
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20
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Yuan F, Liao Y, You W, Liu Z, Tan Y, Zheng C, BinWang, Zhou D, Tian Y, Bei W. Deletion of the znuA virulence factor attenuates Actinobacillus pleuropneumoniae and confers protection against homologous or heterologous strain challenge. Vet Microbiol 2014; 174:531-539. [PMID: 25465668 DOI: 10.1016/j.vetmic.2014.10.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/29/2014] [Accepted: 10/14/2014] [Indexed: 01/10/2023]
Abstract
The znuA gene is known to be important for growth and survival in Escherichia coli, Haemophilus spp., Neisseria gonorrhoeae, and Pasteurella multocida under low Zn(2+) conditions. This gene is also present in Actinobacillus pleuropneumoniae serotype 1; therefore, the aim of this study was to investigate the existence of a similar role for the znuA gene in the growth and virulence of this organism. A precisely defined ΔznuA deletion mutant of A. pleuropneumoniae was constructed based on the sequence of the wild-type SLW01 using transconjugation and counterselection. This mutation was found to be lethal in low-Zn(2+) medium. Furthermore, the ΔznuA mutant strain exhibited attenuated virulence (≥22-fold) as well as reduced mortality and morbidity in a murine (Balb/C) model of infection. The majority of the bacteria were cleared from the lungs within 2 weeks. The ΔznuA mutant strain caused no adverse effects in pigs at doses of up to 1.0×10(9) CFU/mL. The ΔznuA mutant strain induced a significant immune response and conferred 80% and 100% protection on immunised pigs against challenge with A. pleuropneumoniae strains belonging to homologous or heterologous serovars, respectively, compared to the blank controls. The data obtained in this study indicate the potential of the mutant ΔznuA strain for development as a live vaccine capable of inducing reliable cross-serovar protection following intratracheal immunisation.
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Affiliation(s)
- Fangyan Yuan
- Hubei key laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430070, China
| | - Yonghong Liao
- National Research Center for Veterinary Medicine, Luoyang Pulike Bio-engineering Co. Ltd., Luoyang 471003, Henan, China
| | - Wujin You
- Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Zewen Liu
- Hubei key laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430070, China
| | - Yongqiang Tan
- Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Chengkun Zheng
- Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - BinWang
- Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Danna Zhou
- Hubei key laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430070, China
| | - Yongxiang Tian
- Hubei key laboratory of Animal Embryo and Molecular Breeding, Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430070, China.
| | - Weicheng Bei
- Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
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