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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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Guo F, Quan R, Cui Y, Cao X, Wen T, Xu F. Effects of OxyR regulator on oxidative stress, Apx toxin secretion and virulence of Actinobacillus pleuropneumoniae. Front Cell Infect Microbiol 2024; 13:1324760. [PMID: 38268788 PMCID: PMC10806198 DOI: 10.3389/fcimb.2023.1324760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024] Open
Abstract
Introduction Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, poses a significant threat to global swine populations due to its high prevalence, mortality rates, and substantial economic ramifications. Understanding the pathogen's defense mechanisms against host-produced reactive oxygen species is crucial for its survival, with OxyR, a conserved bacterial transcription factor, being pivotal in oxidative stress response. Methods This study investigated the presence and role of OxyR in A. pleuropneumoniae serovar 1-12 reference strains. Transcriptomic analysis was conducted on an oxyR disruption mutant to delineate the biological activities influenced by OxyR. Additionally, specific assays were employed to assess urease activity, catalase expression, ApxI toxin secretion, as well as adhesion and invasion abilities of the oxyR disruption mutant on porcine 3D4/21 and PT cells. A mice challenge experiment was also conducted to evaluate the impact of oxyR inactivation on A. pleuropneumoniae virulence. Results OxyR was identified as a conserved regulator present in A. pleuropneumoniae serovar 1-12 reference strains. Transcriptomic analysis revealed the involvement of OxyR in multiple biological activities. The oxyR disruption resulted in decreased urease activity, elevated catalase expression, enhanced ApxI toxin secretion-attributed to OxyR binding to the apxIBD promoter-and reduced adhesion and invasion abilities on porcine cells. Furthermore, inactivation of oxyR reduced the virulence of A. pleuropneumoniae in a mice challenge experiment. Discussion The findings highlight the pivotal role of OxyR in influencing the virulence mechanisms of A. pleuropneumoniae. The observed effects on various biological activities underscore OxyR as an essential factor contributing to the pathogenicity of this bacterium.
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Affiliation(s)
- Fangfang Guo
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Rong Quan
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Yifang Cui
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Xiaoya Cao
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Tong Wen
- Department of Biology Science and Technology, Baotou Teacher’s College, Baotou, China
| | - Fuzhou Xu
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
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Zhao F, Xu H, Chen Y, Xiao J, Zhang M, Li Z, Liu J, Qi C. Actinobacillus pleuropneumoniae FliY and YdjN are involved in cysteine/cystine utilization, oxidative resistance, and biofilm formation but are not determinants of virulence. Front Microbiol 2023; 14:1169774. [PMID: 37250053 PMCID: PMC10213525 DOI: 10.3389/fmicb.2023.1169774] [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: 02/20/2023] [Accepted: 04/10/2023] [Indexed: 05/31/2023] Open
Abstract
Introduction Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is a member of Actinobacillus in family Pasteurellaceae. It is the causative agent of porcine pleuropneumonia, which has caused huge economic losses to pig industry over the world. Cysteine is a precursor of many important biomolecules and defense compounds in the cell. However, molecular mechanisms of cysteine transport in A. pleuropneumoniae are unclear. Methods In this study, gene-deleted mutants were generated and investigated, to reveal the roles of potential cysteine/cystine transport proteins FliY and YdjN of A. pleuropneumoniae. Results Our results indicated that the growth of A. pleuropneumoniae was not affected after fliY or ydjN single gene deletion, but absence of both FliY and YdjN decreased the growth ability significantly, when cultured in the chemically defined medium (CDM) supplemented with cysteine or cystine as the only sulfur source. A. pleuropneumoniae double deletion mutant ΔfliYΔydjN showed increased sensitivity to oxidative stress. Besides, trans-complementation of YdjN into ΔfliYΔydjN and wild type leads to increased biofilm formation in CDM. However, the virulence of ΔfliYΔydjN was not attenuated in mice or pigs. Discussion These findings suggest that A. pleuropneumoniae FliY and YdjN are involved in the cysteine/cystine acquisition, oxidative tolerance, and biofilm formation, but not contribute to the pathogenicity of A. pleuropneumoniae.
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The Metabolic Adaptation in Response to Nitrate Is Critical for Actinobacillus pleuropneumoniae Growth and Pathogenicity under the Regulation of NarQ/P. Infect Immun 2022; 90:e0023922. [PMID: 35938858 PMCID: PMC9476948 DOI: 10.1128/iai.00239-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nitrate metabolism is an adaptation mechanism used by many bacteria for survival in anaerobic environments. As a by-product of inflammation, nitrate is used by the intestinal bacterial pathogens to enable gut infection. However, the responses of bacterial respiratory pathogens to nitrate are less well understood. Actinobacillus pleuropneumoniae is an important bacterial respiratory pathogen of swine. Previous studies have suggested that adaptation of A. pleuropneumoniae to anaerobiosis is important for infection. In this work, A. pleuropneumoniae growth and pathogenesis in response to the nitrate were investigated. Nitrate significantly promoted A. pleuropneumoniae growth under anaerobic conditions in vitro and lethality in mice. By using narQ and narP deletion mutants and single-residue-mutated complementary strains of ΔnarQ, the two-component system NarQ/P was confirmed to be critical for nitrate-induced growth, with Arg50 in NarQ as an essential functional residue. Transcriptome analysis showed that nitrate upregulated multiple energy-generating pathways, including nitrate metabolism, mannose and pentose metabolism, and glycerolipid metabolism via the regulation of NarQ/P. Furthermore, narQ, narP, and its target gene encoding the nitrate reductase Nap contributed to the pathogenicity of A. pleuropneumoniae. The Nap inhibitor tungstate significantly reduced the survival of A. pleuropneumoniae in vivo, suggesting that Nap is a potential drug target. These results give new insights into how the respiratory pathogen A. pleuropneumoniae utilizes the alternative electron acceptor nitrate to overcome the hypoxia microenvironment, which can occur in the inflammatory or necrotic infected tissues.
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Stancheva SG, Frömbling J, Sassu EL, Hennig-Pauka I, Ladinig A, Gerner W, Grunert T, Ehling-Schulz M. Proteomic and immunoproteomic insights into the exoproteome of Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia. Microb Pathog 2022; 172:105759. [PMID: 36087692 DOI: 10.1016/j.micpath.2022.105759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 10/31/2022]
Abstract
Porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae affects pig health status and the swine industry worldwide. Despite the extensive number of studies focused on A. pleuropneumoniae infection and vaccine development, a thorough analysis of the A. pleuropneumoniae exoproteome is still missing. Using a complementary approach of quantitative proteomics and immunoproteomics we gained an in-depth insight into the A. pleuropneumoniae serotype 2 exoproteome, which provides the basis for future functional studies. Label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed 593 exoproteins, of which 104 were predicted to be virulence factors. The RTX toxins ApxIIA and ApxIIIA -were found to be the most abundant proteins in the A. pleuropneumoniae serotype 2 exoproteome. Furthermore, the ApxIVA toxin was one of the proteins showing the highest abundance, although ApxIVA is commonly assumed to be expressed exclusively in vivo. Our study revealed several antigens, including proteins with moonlight functions, such as the elongation factor (EF)-Tu, and proteins linked to specific metabolic traits, such as the maltodextrin-binding protein MalE, that warrant future functional characterization and might present potential targets for novel therapeutics and vaccines. Our Ig-classes specific serological proteome analysis (SERPA) approach allowed us to explore the development of the host humoral immune response over the course of the infection. These SERPAs pinpointed proteins that might play a key role in virulence and persistence and showed that the immune response to the different Apx toxins is distinct. For instance, our results indicate that the ApxIIIA toxin has properties of a thymus-independent antigen, which should be studied in more detail.
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Affiliation(s)
- Stelli G Stancheva
- Institute of Microbiology, Department for Pathobiology, University of Veterinary Medicine Vienna, Austria
| | - Janna Frömbling
- Institute of Microbiology, Department for Pathobiology, University of Veterinary Medicine Vienna, Austria
| | - Elena L Sassu
- University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Austria
| | - Isabel Hennig-Pauka
- Field Station for Epidemiology, University of Veterinary Medicine Hannover, Bakum, Germany
| | - Andrea Ladinig
- University Clinic for Swine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Austria
| | - Wilhelm Gerner
- Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Tom Grunert
- Institute of Microbiology, Department for Pathobiology, University of Veterinary Medicine Vienna, Austria
| | - Monika Ehling-Schulz
- Institute of Microbiology, Department for Pathobiology, University of Veterinary Medicine Vienna, Austria.
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Lima S, Matinha-Cardoso J, Giner-Lamia J, Couto N, Pacheco CC, Florencio FJ, Wright PC, Tamagnini P, Oliveira P. Extracellular vesicles as an alternative copper-secretion mechanism in bacteria. JOURNAL OF HAZARDOUS MATERIALS 2022; 431:128594. [PMID: 35259694 DOI: 10.1016/j.jhazmat.2022.128594] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 02/18/2022] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Metal homeostasis is fundamental for optimal performance of cell metabolic pathways. Over the course of evolution, several systems emerged to warrant an intracellular metal equilibrium. When exposed to growth-challenging copper concentrations, Gram-negative bacteria quickly activate copper-detoxification mechanisms, dependent on transmembrane-protein complexes and metallochaperones that mediate metal efflux. Here, we show that vesiculation is also a common bacterial response mechanism to high copper concentrations, and that extracellular vesicles (EVs) play a role in transporting copper. We present evidence that bacteria from different ecological niches release copious amounts of EVs when exposed to copper. Along with the activation of the classical detoxification systems, we demonstrate that copper-stressed cells of the cyanobacterium Synechocystis sp. PCC6803 release EVs loaded with the copper-binding metallochaperone CopM. Under standard growth conditions, CopM-loaded EVs could also be isolated from a Synechocystis strain lacking a functional TolC-protein, which we characterize here as exhibiting a copper-sensitive phenotype. Analyses of Synechocystis tolC-mutant's EVs isolated from cells cultivated under standard conditions indicated the presence of copper therein, in significantly higher levels as compared to those from the wild-type. Altogether, these results suggest that release of EVs in bacteria represent a novel copper-secretion mechanism, shedding light into alternative mechanisms of bacterial metal resistance.
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Affiliation(s)
- Steeve Lima
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; MCbiology Doctoral Program, ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Jorge Matinha-Cardoso
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Joaquín Giner-Lamia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC C, Américo Vespucio, 49, 41092 Sevilla, Spain; Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Parque Científico y Tecnológico, UPM Campus de Montegancedo, Ctra, M-40, km 38, 28223 Madrid, Spain; Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Campus, Av. Puerta de Hierro, nº 2, 4, 28040 Madrid, Spain
| | - Narciso Couto
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin St, Sheffield City Centre, Sheffield S1 4NL, United Kingdom
| | - Catarina C Pacheco
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Francisco J Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC C, Américo Vespucio, 49, 41092 Sevilla, Spain; Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Avenida Reina Mercedes s/n, 41012 Sevilla, Spain
| | - Phillip C Wright
- University of Southampton, Office of the President and Vice Chancellor B37, University Rd, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Paula Tamagnini
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Paulo Oliveira
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
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Chen X, Shao Z, Wu L, He B, Yang W, Chen J, Jin E, Huang Q, Lei L, Xu J, Li H, Zhang H, Wan Y, Liu W, Zhou R. Involvement of the Actinobacillus pleuropneumoniae ompW Gene in Confrontation of Environmental Pressure. Front Vet Sci 2022; 9:846322. [PMID: 35664844 PMCID: PMC9161549 DOI: 10.3389/fvets.2022.846322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 04/28/2022] [Indexed: 11/13/2022] Open
Abstract
Actinobacillus pleuropneumoniae causes porcine pleuropneumonia. The function of the outer membrane protein W gene (ompW) of A. pleuropneumoniae has not been evaluated. Thus a deletion mutant of ompW, ΔompW, was constructed to explore the effect of ompW gene deletion on bacterial growth, biofilm formation, bacterial morphology, oxidative tolerance, susceptibility to antibiotics, and the expression of ribosome synthesis and ABC transporter related genes. Results showed that the ompW gene deletion did not affect biofilm formation and the growth of A. pleuropneumoniae but did affect bacterial morphology during steady growth, oxidative tolerance, and bacterial susceptibility to polymyxin B, kanamycin, and penicillin. The ompW gene deletion also affected the expression of ribosome synthesis and ABC transporter related genes. These results suggested that ompW may regulate the biological phenotype of A. pleuropneumoniae.
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Affiliation(s)
- Xiabing Chen
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, China
- *Correspondence: Xiabing Chen
| | - Zhiyong Shao
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Lijun Wu
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Bin He
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Wenhai Yang
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Jie Chen
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Erguang Jin
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Qi Huang
- State Key Laboratory of Agricultural Microbiology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center for Sustainable Pig Production, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Liancheng Lei
- College of Veterinary Medicine and College of Animal Science, Jilin University, Changchun, China
| | - Jiajia Xu
- State Key Laboratory of Agricultural Microbiology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center for Sustainable Pig Production, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Haotian Li
- State Key Laboratory of Agricultural Microbiology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center for Sustainable Pig Production, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Hui Zhang
- State Key Laboratory of Agricultural Microbiology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center for Sustainable Pig Production, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Yun Wan
- Wuhan Animal Disease Control Center, Wuhan, China
| | - Wu Liu
- Institute of Animal Husbandry and Veterinary Science, Wuhan Academy of Agricultural Sciences, Wuhan, China
- Wu Liu
| | - Rui Zhou
- State Key Laboratory of Agricultural Microbiology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Cooperative Innovation Center for Sustainable Pig Production, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
- Rui Zhou
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Abstract
Actinobacillus pleuropneumoniae causes porcine pleuropneumonia, an important disease in the pig industry. Accurate and sensitive diagnostics such as DNA-based diagnostics are essential for preventing or responding to an outbreak. The specificity of DNA-based diagnostics depends on species-specific markers. Previously, an insertion element was found within an A. pleuropneumoniae-specific gene commonly used for A. pleuropneumoniae detection, prompting the need for additional species-specific markers. Herein, 12 marker candidates highly conserved (99 - 100% identity) among 34 A. pleuropneumoniae genomes (covering 13 serovars) were identified to be A. pleuropneumoniae-specific in silico, as these sequences are distinct from 30 genomes of 13 other Actinobacillus and problematic [Actinobacillus] species and more than 1700 genomes of other bacteria in the Pasteurellaceae family. Five marker candidates are within the apxIVA gene, a known A. pleuropneumoniae-specific gene, validating our in silico marker discovery method. Seven other A. pleuropneumoniae-specific marker candidates within the eamA, nusG, sppA, xerD, ybbN, ycfL, and ychJ genes were validated by polymerase chain reaction (PCR) to be specific to 129 isolates of A. pleuropneumoniae (covering all 19 serovars), but not to four closely related Actinobacillus species, four [Actinobacillus] species, or seven other bacterial species. This is the first study to identify A. pleuropneumoniae-specific markers through genome mining. Seven novel A. pleuropneumoniae-specific DNA markers were identified by a combination of in silico and molecular methods and can serve as additional or alternative targets for A. pleuropneumoniae diagnostics, potentially leading to better control of the disease. IMPORTANCE Species-specific markers are crucial for infectious disease diagnostics. Mutations within a marker sequence can lead to false-negative results, inappropriate treatment, and economic loss. The availability of several species-specific markers is therefore desirable. In this study, 12 DNA markers specific to A. pleuropneumoniae, a pig pathogen, were simultaneously identified. Five marker candidates are within a known A. pleuropneumoniae-specific gene. Seven novel markers can be used as additional targets in DNA-based diagnostics, which in turn can expedite disease diagnosis, assist farm management, and lead to better animal health and food security. The marker discovery strategy outlined herein requires less time, effort, and cost, and results in more markers compared with conventional methods. Identification of species-specific markers of other pathogens and corresponding infectious disease diagnostics are possible, conceivably improving health care and the economy.
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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: 9] [Impact Index Per Article: 3.0] [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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11
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Dao HT, Truong QL, Do VT, Hahn TW. Construction and immunization with double mutant Δ apxIBD Δ pnp forms of Actinobacillus pleuropneumoniae serotypes 1 and 5. J Vet Sci 2020; 21:e20. [PMID: 32233129 PMCID: PMC7113565 DOI: 10.4142/jvs.2020.21.e20] [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: 10/16/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 12/14/2022] Open
Abstract
Actinobacillus pleuropneumoniae (APP) causes a form of porcine pleuropneumonia that leads to significant economic losses in the swine industry worldwide. The apxIBD gene is responsible for the secretion of the ApxI and ApxII toxins and the pnp gene is responsible for the adaptation of bacteria to cold temperature and a virulence factor. The apxIBD and pnp genes were deleted successfully from APP serotype 1 and 5 by transconjugation and sucrose counter-selection. The APP1ΔapxIBDΔpnp and APP5ΔapxIBDΔpnp mutants lost hemolytic activity and could not secrete ApxI and ApxII toxins outside the bacteria because both mutants lost the ApxI- and ApxII-secreting proteins by deletion of the apxIBD gene. Besides, the growth of these mutants was defective at low temperatures resulting from the deletion of pnp. The APP1ΔapxIBDΔpnp and APP5ΔapxIBDΔpnp mutants were significantly attenuated compared with wild-type ones. However, mice vaccinated intraperitoneally with APP5ΔapxIBDΔpnp did not provide any protection when challenged with a 10-times 50% lethal dose of virulent homologous (APP5) and heterologous (APP1) bacterial strains, while mice vaccinated with APP1ΔapxIBDΔpnp offered 75% protection against a homologous challenge. The ΔapxIBDΔpnp mutants were significantly attenuated and gave different protection rate against homologous virulent wild-type APP challenging.
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Affiliation(s)
- Hoai Thu Dao
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Quang Lam Truong
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea.,Key Laboratory of Veterinary Medicine, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi 100000, Vietnam
| | - Van Tan Do
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Tae Wook Hahn
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea.
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12
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Yan K, Liu T, Duan B, Liu F, Cao M, Peng W, Dai Q, Chen H, Yuan F, Bei W. The CpxAR Two-Component System Contributes to Growth, Stress Resistance, and Virulence of Actinobacillus pleuropneumoniae by Upregulating wecA Transcription. Front Microbiol 2020; 11:1026. [PMID: 32528444 PMCID: PMC7255013 DOI: 10.3389/fmicb.2020.01026] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/27/2020] [Indexed: 12/14/2022] Open
Abstract
Actinobacillus pleuropneumoniae is the pathogen of porcine contagious pleuropneumonia. In A. pleuropneumoniae, the CpxAR two-component system is essential for fitness and growth. The O-antigen protrudes from the outer membrane to the exterior of the cell, and the outer membrane serves as a barrier that helps the bacteria to survive in harsh environments. WecA, a undecaprenyl phosphate GlcNAc-1-phosphate transferase, is involved in O-antigen repeating unit biosynthesis. In this study, we investigated the role of CpxAR in the expression of wecA in A. pleuropneumoniae. Our results revealed that CpxR positively regulates wecA expression by directly binding to the putative promoter region of wecA. Wild-type, ΔcpxAR, ΔwecA, and complemented strains were investigated under serum, oxidative, and osmotic stresses. The ΔcpxAR and ΔwecA strains were more susceptible to these stresses than the wild-type, but the complemented strains showed phenotypes similar to those of the wild-type. Mice infected with the ΔcpxAR and ΔwecA strains exhibited lower mortality and bacterial loads in the lung than those infected with the wild-type or complemented strains. This study reveals that the CpxAR two-component system contributes to A. pleuropneumoniae growth, stress resistance, and virulence, by upregulating expression of wecA. Our findings provide new insight into the pathogenesis of A. pleuropneumoniae.
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Affiliation(s)
- Kang Yan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Ting Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Benzhen Duan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Feng Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Manman Cao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Wei Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Qi Dai
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, 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
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.,State Key Laboratory of Genetically Engineered Veterinary Vaccines, Qingdao, China.,The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China
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13
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The antimicrobial peptide MPX kills Actinobacillus pleuropneumoniae and reduces its pathogenicity in mice. Vet Microbiol 2020; 243:108634. [PMID: 32273013 DOI: 10.1016/j.vetmic.2020.108634] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 02/22/2020] [Accepted: 03/02/2020] [Indexed: 01/03/2023]
Abstract
Actinobacillus pleuropneumoniae is the causative agent of highly contagious and fatal respiratory infections, causing substantial economic losses to the global pig industry. Due to increased antibiotic resistance, there is an urgent need to find new antibiotic alternatives for treating A. pleuropneumoniae infections. MPX is obtained from wasp venom and has a killing effect on various bacteria. This study found that MPX had a good killing effect on A. pleuropneumoniae and that the minimum inhibitory concentration (MIC) was 16 μg/mL. The bacterial density of A. pleuropneumoniae decreased 1000 times after MPX (1 × MIC) treatment for 1 h, and the antibacterial activity was not affected by pH or temperature. Fluorescence microscopy showed that MPX (1 × MIC) destroyed the bacterial cell membrane after treatment for 0.5 h, increasing membrane permeability and releasing bacterial proteins and Ca2+, Na+ and other cations. In addition, MPX (1 × MIC) treatment significantly reduced the formation of bacterial biofilms. Quantitative RT-PCR results showed that MPX treatment significantly upregulated the expression of the PurC virulence gene and downregulated that of ApxI, ApxII, and Apa1. In addition, the Sap A gene was found to play an important role in the tolerance of A. pleuropneumoniae to antimicrobial peptides. Therapeutic evaluation in a murine model showed that MPX protects mice from a lethal dose of A. pleuropneumoniae and relieves lung inflammation. This study reports the use of MPX to treat A. pleuropneumonia infections, laying the foundation for the development of new drugs for bacterial infections.
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