The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Mario Jacques - One of the best experts on this subject based on the ideXlab platform.
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Actinobacillus Pleuropneumoniae biofilms: Role in pathogenicity and potential impact for vaccination development
Animal Health Research Reviews, 2018Co-Authors: Skander Hathroubi, Abraham Loera-muro, Alma Guerrero-barrera, Yannick Tremblay, Mario JacquesAbstract:Actinobacillus Pleuropneumoniae is a Gram-negative bacterium that belongs to the family Pasteurellaceae. It is the causative agent of Porcine Pleuropneumonia, a highly contagious respiratory disease that is responsible for major economic losses in the global pork industry. The disease may present itself as a chronic or an acute infection characterized by severe pathology, including hemorrhage, fibrinous and necrotic lung lesions, and, in the worst cases, rapid death. A. Pleuropneumoniae is transmitted via aerosol route, direct contact with infected pigs, and by the farm environment. Many virulence factors associated with this bacterium are well characterized. However, much less is known about the role of biofilm, a sessile mode of growth that may have a critical impact on A. Pleuropneumoniae pathogenicity. Here we review the current knowledge on A. Pleuropneumoniae biofilm, factors associated with biofilm formation and dispersion, and the impact of biofilm on the pathogenesis A. Pleuropneumoniae. We also provide an overview of current vaccination strategies against A. Pleuropneumoniae and consider the possible role of biofilms vaccines for controlling the disease.
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Incorporation of Actinobacillus Pleuropneumoniae in Preformed Biofilms by Escherichia coli Isolated From Drinking Water of Swine Farms
Frontiers Media S.A., 2018Co-Authors: Flor Y. Ramírez-castillo, Mario Jacques, Abraham Loera-muro, Josee Harel, Nicy D. Vargas-padilla, Adriana C. Moreno-flores, Francisco J. Avelar-gonzález, Ricardo Oropeza, Carolina C. Barajas-garcía, Alma Guerrero-barreraAbstract:Actinobacillus Pleuropneumoniae, the etiological agent of Porcine Pleuropneumonia, represents one of the most important health problems in the swine industry worldwide and it is included in the Porcine respiratory disease complex. One of the bacterial survival strategies is biofilm formation, which are bacterial communities embedded in an extracellular matrix that could be attached to a living or an inert surface. Until recently, A. Pleuropneumoniae was considered to be an obligate pathogen. However, recent studies have shown that A. Pleuropneumoniae is present in farm drinking water. In this study, the drinking water microbial communities of Aguascalientes (Mexico) swine farms were analyzed, where the most frequent isolated bacterium was Escherichia coli. Biofilm formation was tested in vitro; producing E. coli biofilms under optimal growth conditions; subsequently, A. Pleuropneumoniae serotype 1 (strains 4074 and 719) was incorporated to these biofilms. Interaction between both bacteria was evidenced, producing an increase in biofilm formation. Extracellular matrix composition of two-species biofilms was also characterized using fluorescent markers and enzyme treatments. In conclusion, results confirm that A. Pleuropneumoniae is capable of integrates into biofilms formed by environmental bacteria, indicative of a possible survival strategy in the environment and a mechanism for disease dispersion
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surface polysaccharide mutants reveal that absence of o antigen reduces biofilm formation of actinobacillus Pleuropneumoniae
Infection and Immunity, 2016Co-Authors: Skander Hathroubi, Paul R. Langford, Josée Labrie, Janine T. Bossé, Yannick D. N. Tremblay, Mark A Hancock, Mario JacquesAbstract:Actinobacillus Pleuropneumoniae is a Gram-negative bacterium belonging to the Pasteurellaceae family and the causative agent of Porcine Pleuropneumonia, a highly contagious lung disease causing important economic losses. Surface polysaccharides, including lipopolysaccharides (LPS) and capsular polysaccharides (CPS), are implicated in the adhesion and virulence of A. Pleuropneumoniae, but their role in biofilm formation is still unclear. In this study, we investigated the requirement for these surface polysaccharides in biofilm formation by A. Pleuropneumoniae serotype 1. Well-characterized mutants were used: an O-antigen LPS mutant, a truncated core LPS mutant with an intact O antigen, a capsule mutant, and a poly-N-acetylglucosamine (PGA) mutant. We compared the amount of biofilm produced by the parental strain and the isogenic mutants using static and dynamic systems. Compared to the findings for the biofilm of the parental or other strains, the biofilm of the O antigen and the PGA mutants was dramatically reduced, and it had less cell-associated PGA. Real-time PCR analyses revealed a significant reduction in the level of pgaA, cpxR, and cpxA mRNA in the biofilm cells of the O-antigen mutant compared to that in the biofilm cells of the parental strain. Specific binding between PGA and LPS was consistently detected by surface plasmon resonance, but the lack of O antigen did not abolish these interactions. In conclusion, the absence of the O antigen reduces the ability of A. Pleuropneumoniae to form a biofilm, and this is associated with the reduced expression and production of PGA.
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Actinobacillus Pleuropneumoniae induces SJPL cell cycle arrest in G2/M-phase and inhibits Porcine reproductive and respiratory syndrome virus replication
Virology Journal, 2015Co-Authors: Jérémy A. Ferreira Barbosa, Josée Labrie, Francis Beaudry, Carl A. Gagnon, Mario JacquesAbstract:Background Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry and causes important economic losses. No effective antiviral drugs against it are commercially available. We recently reported that the culture supernatant of Actinobacillus Pleuropneumoniae , the Porcine Pleuropneumonia causative agent, has an antiviral activity in vitro against PRRSV in SJPL cells. Objectives of this study were (i) to identify the mechanism behind the antiviral activity displayed by A. Pleuropneumoniae and (ii) to characterize the active molecules present in the bacterial culture supernatant. Methods Antibody microarray analysis was used in order to point out cellular pathways modulated by the A. Pleuropneumoniae supernatant. Subsequent, flow cytometry analysis and cell cycle inhibitors were used to confirm antibody microarray data and to link them to the antiviral activity of the A. Pleuropneumoniae supernatant. Finally, A. Pleuropneumoniae supernatant characterization was partially achieved using mass spectrometry. Results Using antibody microarray, we observed modulations in G2/M-phase cell cycle regulation pathway when SJPL cells were treated with A. Pleuropneumoniae culture supernatant. These modulations were confirmed by a cell cycle arrest at the G2/M-phase when cells were treated with the A. Pleuropneumoniae culture supernatant. Furthermore, two G2/M-phase cell cycle inhibitors demonstrated the ability to inhibit PRRSV infection, indicating a potential key role for PRRSV infection. Finally, mass spectrometry lead to identify two molecules (m/z 515.2 and m/z 663.6) present only in the culture supernatant. Conclusions We demonstrated for the first time that A. Pleuropneumoniae is able to disrupt SJPL cell cycle resulting in inhibitory activity against PRRSV. Furthermore, two putative molecules were identified from the culture supernatant. This study highlighted the cell cycle importance for PRRSV and will allow the development of new prophylactic or therapeutic approaches against PRRSV.
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actinobacillus Pleuropneumoniae induces sjpl cell cycle arrest in g2 m phase and inhibits Porcine reproductive and respiratory syndrome virus replication
Virology Journal, 2015Co-Authors: Jeremy Ferreira A Barbosa, Josée Labrie, Francis Beaudry, Carl A. Gagnon, Mario JacquesAbstract:Background: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry and causes important economic losses. No effective antiviral drugs against it are commercially available. We recently reported that the culture supernatant of Actinobacillus Pleuropneumoniae, the Porcine Pleuropneumonia causative agent, has an antiviral activity in vitro against PRRSV in SJPL cells. Objectives of this study were (i) to identify the mechanism behind the antiviral activity displayed by A. Pleuropneumoniae and (ii) to characterize the active molecules present in the bacterial culture supernatant. Methods: Antibody microarray analysis was used in order to point out cellular pathways modulated by the A. Pleuropneumoniae supernatant. Subsequent, flow cytometry analysis and cell cycle inhibitors were used to confirm antibody microarray data and to link them to the antiviral activity of the A. Pleuropneumoniae supernatant. Finally, A. Pleuropneumoniae supernatant characterization was partially achieved using mass spectrometry. Results: Using antibody microarray, we observed modulations in G2/M-phase cell cycle regulation pathway when SJPL cells were treated with A. Pleuropneumoniae culture supernatant. These modulations were confirmed by a cell cycle arrest at the G2/M-phase when cells were treated with the A. Pleuropneumoniae culture supernatant. Furthermore, two G2/M-phase cell cycle inhibitors demonstrated the ability to inhibit PRRSV infection, indicating a potential key role for PRRSV infection. Finally, mass spectrometry lead to identify two molecules (m/z 515.2 and m/z 663.6) present only in the culture supernatant. Conclusions: We demonstrated for the first time that A. Pleuropneumoniae is able to disrupt SJPL cell cycle resulting in inhibitory activity against PRRSV. Furthermore, two putative molecules were identified from the culture supernatant. This study highlighted the cell cycle importance for PRRSV and will allow the development of new prophylactic or therapeutic approaches against PRRSV.
Janine T. Bossé - One of the best experts on this subject based on the ideXlab platform.
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comparative sequence analysis of the capsular polysaccharide loci of actinobacillus Pleuropneumoniae serovars 1 18 and development of two multiplex pcrs for comprehensive capsule typing
Veterinary Microbiology, 2018Co-Authors: Janine T. Bossé, Roberto Fernandez Crespo, Sonia Lacouture, Marcelo Gottschalk, Rita Sarkozi, L Fodor, Maria Casas Amoribieta, Oystein Angen, Katerina Nedbalcova, Matthew T G HoldenAbstract:Problems with serological cross-reactivity have led to development of a number of PCRs (individual and multiplex) for molecular typing of Actinobacillus Pleuropneumoniae, the causative agent of Porcine Pleuropneumonia. Most of these assays were developed for detection of specific amplicons within capsule biosynthetic genes before the availability of complete sequences for the different serovars. Here we describe comparative analysis of the complete capsular loci for all 18 serovars of A. Pleuropneumoniae, and development of two multiplex PCRs for comprehensive capsule typing of this important pig pathogen.
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update on actinobacillus Pleuropneumoniae knowledge gaps and challenges
Transboundary and Emerging Diseases, 2018Co-Authors: Elena L Sassu, Paul R. Langford, Janine T. Bossé, T J Tobias, M Gottschalk, Isabel HennigpaukaAbstract:Porcine Pleuropneumonia, caused by the bacterial Porcine respiratory tract pathogen Actinobacillus Pleuropneumoniae, leads to high economic losses in affected swine herds in most countries of the world. Pigs affected by peracute and acute disease suffer from severe respiratory distress with high lethality. The agent was first described in 1957 and, since then, knowledge about the pathogen itself, and its interactions with the host, has increased continuously. This is, in part, due to the fact that experimental infections can be studied in the natural host. However, the fact that most commercial pigs are colonized by this pathogen has hampered the applicability of knowledge gained under experimental conditions. In addition, several factors are involved in development of disease, and these have often been studied individually. In a DISCONTOOLS initiative, members from science, industry and clinics exchanged their expertise and empirical observations and identified the major gaps in knowledge. This review sums up published results and expert opinions, within the fields of pathogenesis, epidemiology, transmission, immune response to infection, as well as the main means of prevention, detection and control. The gaps that still remain to be filled are highlighted, and present as well as future challenges in the control of this disease are addressed.
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Identification and characterization of serovar-independent immunogens in Actinobacillus Pleuropneumoniae
Veterinary Research, 2017Co-Authors: Fabio Antenucci, Janine T. Bossé, Cyrielle Fougeroux, Peter Johannes Holst, Zofia Magnowska, Camille Roesch, Paul Langford, Anders Miki BojesenAbstract:AbstractDespite 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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the n linking glycosylation system from actinobacillus Pleuropneumoniae is required for adhesion and has potential use in glycoengineering
Open Biology, 2017Co-Authors: Jon Cuccui, Andrew N. Rycroft, Janine T. Bossé, Alexander W Tucker, Vanessa S Terra, Andreas Naegeli, Sherif Abouelhadid, Chiawei Lin, Prerna Vohra, Duncan J MaskellAbstract:Actinobacillus Pleuropneumoniae is a mucosal respiratory pathogen causing contagious Porcine Pleuropneumonia. Pathogenesis studies have demonstrated a major role for the capsule, exotoxins and outer membrane proteins. Actinobacillus Pleuropneumoniae can also glycosylate proteins, using a cytoplasmic N-linked glycosylating enzyme designated NGT, but its transcriptional arrangement and role in virulence remains unknown. We investigated the NGT locus and demonstrated that the putative transcriptional unit consists of rimO, ngt and a glycosyltransferase termed agt. From this information we used the A. Pleuropneumoniae glycosylation locus to decorate an acceptor protein, within Escherichia coli, with a hexose polymer that reacted with an anti-dextran antibody. Mass spectrometry analysis of a truncated protein revealed that this operon could add up to 29 repeat units to the appropriate sequon. We demonstrated the importance of NGT in virulence, by creating deletion mutants and testing them in a novel respiratory cell line adhesion model. This study demonstrates the importance of the NGT glycosylation system for pathogenesis and its potential biotechnological application for glycoengineering.
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a computational strategy for the search of regulatory small rnas in actinobacillus Pleuropneumoniae
RNA, 2016Co-Authors: Ciro Cesar Rossi, Paul R. Langford, Janine T. Bossé, Adam A Witney, Kate Gould, Denise Mara Soares BazzolliAbstract:Bacterial regulatory small RNAs (sRNAs) play important roles in gene regulation and are frequently connected to the expression of virulence factors in diverse bacteria. Only a few sRNAs have been described for Pasteurellaceae pathogens and no in-depth analysis of sRNAs has been described for Actinobacillus Pleuropneumoniae, the causative agent of Porcine Pleuropneumonia, responsible for considerable losses in the swine industry. To search for sRNAs in A. Pleuropneumoniae, we developed a strategy for the computational analysis of the bacterial genome by using four algorithms with different approaches, followed by experimental validation. The coding strand and expression of 17 out of 23 RNA candidates were confirmed by Northern blotting, RT-PCR, and RNA sequencing. Among them, two are likely riboswitches, three are housekeeping regulatory RNAs, two are the widely studied GcvB and 6S sRNAs, and 10 are putative novel trans-acting sRNAs, never before described for any bacteria. The latter group has several potential mRNA targets, many of which are involved with virulence, stress resistance, or metabolism, and connect the sRNAs in a complex gene regulatory network. The sRNAs identified are well conserved among the Pasteurellaceae that are evolutionarily closer to A. Pleuropneumoniae and/or share the same host. Our results show that the combination of newly developed computational programs can be successfully utilized for the discovery of novel sRNAs and indicate an intricate system of gene regulation through sRNAs in A. Pleuropneumoniae and in other Pasteurellaceae, thus providing clues for novel aspects of virulence that will be explored in further studies.
Josée Labrie - One of the best experts on this subject based on the ideXlab platform.
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surface polysaccharide mutants reveal that absence of o antigen reduces biofilm formation of actinobacillus Pleuropneumoniae
Infection and Immunity, 2016Co-Authors: Skander Hathroubi, Paul R. Langford, Josée Labrie, Janine T. Bossé, Yannick D. N. Tremblay, Mark A Hancock, Mario JacquesAbstract:Actinobacillus Pleuropneumoniae is a Gram-negative bacterium belonging to the Pasteurellaceae family and the causative agent of Porcine Pleuropneumonia, a highly contagious lung disease causing important economic losses. Surface polysaccharides, including lipopolysaccharides (LPS) and capsular polysaccharides (CPS), are implicated in the adhesion and virulence of A. Pleuropneumoniae, but their role in biofilm formation is still unclear. In this study, we investigated the requirement for these surface polysaccharides in biofilm formation by A. Pleuropneumoniae serotype 1. Well-characterized mutants were used: an O-antigen LPS mutant, a truncated core LPS mutant with an intact O antigen, a capsule mutant, and a poly-N-acetylglucosamine (PGA) mutant. We compared the amount of biofilm produced by the parental strain and the isogenic mutants using static and dynamic systems. Compared to the findings for the biofilm of the parental or other strains, the biofilm of the O antigen and the PGA mutants was dramatically reduced, and it had less cell-associated PGA. Real-time PCR analyses revealed a significant reduction in the level of pgaA, cpxR, and cpxA mRNA in the biofilm cells of the O-antigen mutant compared to that in the biofilm cells of the parental strain. Specific binding between PGA and LPS was consistently detected by surface plasmon resonance, but the lack of O antigen did not abolish these interactions. In conclusion, the absence of the O antigen reduces the ability of A. Pleuropneumoniae to form a biofilm, and this is associated with the reduced expression and production of PGA.
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Actinobacillus Pleuropneumoniae induces SJPL cell cycle arrest in G2/M-phase and inhibits Porcine reproductive and respiratory syndrome virus replication
Virology Journal, 2015Co-Authors: Jérémy A. Ferreira Barbosa, Josée Labrie, Francis Beaudry, Carl A. Gagnon, Mario JacquesAbstract:Background Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry and causes important economic losses. No effective antiviral drugs against it are commercially available. We recently reported that the culture supernatant of Actinobacillus Pleuropneumoniae , the Porcine Pleuropneumonia causative agent, has an antiviral activity in vitro against PRRSV in SJPL cells. Objectives of this study were (i) to identify the mechanism behind the antiviral activity displayed by A. Pleuropneumoniae and (ii) to characterize the active molecules present in the bacterial culture supernatant. Methods Antibody microarray analysis was used in order to point out cellular pathways modulated by the A. Pleuropneumoniae supernatant. Subsequent, flow cytometry analysis and cell cycle inhibitors were used to confirm antibody microarray data and to link them to the antiviral activity of the A. Pleuropneumoniae supernatant. Finally, A. Pleuropneumoniae supernatant characterization was partially achieved using mass spectrometry. Results Using antibody microarray, we observed modulations in G2/M-phase cell cycle regulation pathway when SJPL cells were treated with A. Pleuropneumoniae culture supernatant. These modulations were confirmed by a cell cycle arrest at the G2/M-phase when cells were treated with the A. Pleuropneumoniae culture supernatant. Furthermore, two G2/M-phase cell cycle inhibitors demonstrated the ability to inhibit PRRSV infection, indicating a potential key role for PRRSV infection. Finally, mass spectrometry lead to identify two molecules (m/z 515.2 and m/z 663.6) present only in the culture supernatant. Conclusions We demonstrated for the first time that A. Pleuropneumoniae is able to disrupt SJPL cell cycle resulting in inhibitory activity against PRRSV. Furthermore, two putative molecules were identified from the culture supernatant. This study highlighted the cell cycle importance for PRRSV and will allow the development of new prophylactic or therapeutic approaches against PRRSV.
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actinobacillus Pleuropneumoniae induces sjpl cell cycle arrest in g2 m phase and inhibits Porcine reproductive and respiratory syndrome virus replication
Virology Journal, 2015Co-Authors: Jeremy Ferreira A Barbosa, Josée Labrie, Francis Beaudry, Carl A. Gagnon, Mario JacquesAbstract:Background: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry and causes important economic losses. No effective antiviral drugs against it are commercially available. We recently reported that the culture supernatant of Actinobacillus Pleuropneumoniae, the Porcine Pleuropneumonia causative agent, has an antiviral activity in vitro against PRRSV in SJPL cells. Objectives of this study were (i) to identify the mechanism behind the antiviral activity displayed by A. Pleuropneumoniae and (ii) to characterize the active molecules present in the bacterial culture supernatant. Methods: Antibody microarray analysis was used in order to point out cellular pathways modulated by the A. Pleuropneumoniae supernatant. Subsequent, flow cytometry analysis and cell cycle inhibitors were used to confirm antibody microarray data and to link them to the antiviral activity of the A. Pleuropneumoniae supernatant. Finally, A. Pleuropneumoniae supernatant characterization was partially achieved using mass spectrometry. Results: Using antibody microarray, we observed modulations in G2/M-phase cell cycle regulation pathway when SJPL cells were treated with A. Pleuropneumoniae culture supernatant. These modulations were confirmed by a cell cycle arrest at the G2/M-phase when cells were treated with the A. Pleuropneumoniae culture supernatant. Furthermore, two G2/M-phase cell cycle inhibitors demonstrated the ability to inhibit PRRSV infection, indicating a potential key role for PRRSV infection. Finally, mass spectrometry lead to identify two molecules (m/z 515.2 and m/z 663.6) present only in the culture supernatant. Conclusions: We demonstrated for the first time that A. Pleuropneumoniae is able to disrupt SJPL cell cycle resulting in inhibitory activity against PRRSV. Furthermore, two putative molecules were identified from the culture supernatant. This study highlighted the cell cycle importance for PRRSV and will allow the development of new prophylactic or therapeutic approaches against PRRSV.
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sub inhibitory concentrations of penicillin g induce biofilm formation by field isolates of actinobacillus Pleuropneumoniae
Veterinary Microbiology, 2015Co-Authors: Skander Hathroubi, Josée Labrie, Yannick D. N. Tremblay, S E Fontainegosselin, Mario JacquesAbstract:Abstract Actinobacillus Pleuropneumoniae is a Gram-negative bacterium and causative agent of Porcine Pleuropneumonia. This is a highly contagious disease that causes important economic losses to the swine industry worldwide. Penicillins are extensively used in swine production and these antibiotics are associated with high systemic clearance and low oral bioavailability. This may expose A. Pleuropneumoniae to sub-inhibitory concentrations of penicillin G when the antibiotic is administered orally. Our goal was to evaluate the effect of sub-minimum inhibitory concentration (MIC) of penicillin G on the biofilm formation of A. Pleuropneumoniae. Biofilm production of 13 field isolates from serotypes 1, 5a, 7 and 15 was tested in the presence of sub-MIC of penicillin G using a polystyrene microtiter plate assay. Using microscopy techniques and enzymatic digestion, biofilm architecture and composition were also characterized after exposure to sub-MIC of penicillin G. Sub-MIC of penicillin G significantly induced biofilm formation of nine isolates. The penicillin G-induced biofilms contained more poly-N-acetyl- d -glucosamine (PGA), extracellular DNA and proteins when compared to control biofilms grown without penicillin G. Additionally, penicillin G-induced biofilms were sensitive to DNase which was not observed with the untreated controls. Furthermore, sub-MIC of penicillin G up-regulated the expression of pgaA , which encodes a protein involved in PGA synthesis, and the genes encoding the envelope-stress sensing two-component regulatory system CpxRA. In conclusion, sub-MICs of penicillin G significantly induce biofilm formation and this is likely the result of a cell envelope stress sensed by the CpxRA system resulting in an increased production of PGA and other matrix components.
Paul R. Langford - One of the best experts on this subject based on the ideXlab platform.
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establishment and comparison of actinobacillus Pleuropneumoniae experimental infection model in mice and piglets
Microbial Pathogenesis, 2019Co-Authors: Chuntong Bao, Paul R. Langford, Jiameng Xiao, Baijun Liu, Jianfang Liu, Rining Zhu, Peng Jiang, Liancheng LeiAbstract:Abstract Actinobacillus Pleuropneumoniae (APP) causes Porcine Pleuropneumonia, a disease responsible for substantial losses in the worldwide pig industry. In this study, outbred Kunming (KM) and Institute of Cancer Research (ICR) mice were evaluated as alternative mice models for APP research. After intranasal infection of serotype 5 reference strain L20, there was less lung damage and a lower clinical sign score in ICR compared to KM mice. However, ICR mice showed more obvious changes in body weight loss, the amount of immune cells (such as neutrophils and lymphocytes) and cytokines (such as IL-6, IL-1β and TNF-α) in blood and bronchoalveolar lavage fluid (BALF). The immunological changes observed in ICR mice closely mimicked those found in piglets infected with L20. While both ICR and KM mice are susceptible to APP and induce pathological lesions, we suggest that ICR and KM mice are more suitable for immunological and pathogenesis studies, respectively. The research lays the theoretical basis for determine that mice could replace pigs as the APP infection model and it is of significance for the study of APP infection in the laboratory.
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transcriptomic analysis of Porcine pbmcs in response to actinobacillus Pleuropneumoniae reveals the dynamic changes of differentially expressed genes related to immuno inflammatory responses
Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology, 2018Co-Authors: Hexiang Jiang, Paul R. Langford, Chuntong Bao, Jianfang Liu, Rining Zhu, Hongtao Liu, Abdalla Eltahir, Diangang Sun, Zhonghua Liu, Changjiang SunAbstract:Actinobacillus Pleuropneumoniae is the cause of Porcine Pleuropneumonia, for which the mortality rate is high. Host peripheral blood is a body site for the immune clearance of pathogens mediated by release of inflammatory factors. However, “out of control” inflammatory factor release can contribute to host death. To further understand the changes in the transcription level of immune-related effectors, samples of peripheral blood mononuclear cells (PBMCs) collected from piglets at different stages of infection (0, 24 and 120 h) were sequenced on an Illumina HiSeq™ 4000 platform. We found 3818 differentially expressed genes (DEGs) in the 24 h-infection group compared to the 0 h-infection group (Pb24-Vs-Pb0). DEGs mainly involved in the Gene ontology and KEGG pathways that included nucleic acid metabolism regulation, cell growth, cell differentiation, and organ morphological maintenance were not significantly enriched (P > 0.05). However, DEGs associated with protein kinase activity, receptor activation, metabolism, local adhesion and immune inflammatory responses were significantly enriched in Pb120-Vs-Pb24 (P < 0.05), as were those related to the T cell receptor signalling pathway, with most being down-regulated compared to the preceding stage (Pb24-Vs-Pb0). In PBMCs there were some changes in glucose metabolism, local adhesion and the immune inflammatory response (Pb120-Vs-Pb0). In addition, up-regulated DEGs, such as IL8, IL1β, and CCL2, and were significantly enriched in immune-inflammatory related pathways compared to the uninfected stage, although they began to decline after 24 h.
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update on actinobacillus Pleuropneumoniae knowledge gaps and challenges
Transboundary and Emerging Diseases, 2018Co-Authors: Elena L Sassu, Paul R. Langford, Janine T. Bossé, T J Tobias, M Gottschalk, Isabel HennigpaukaAbstract:Porcine Pleuropneumonia, caused by the bacterial Porcine respiratory tract pathogen Actinobacillus Pleuropneumoniae, leads to high economic losses in affected swine herds in most countries of the world. Pigs affected by peracute and acute disease suffer from severe respiratory distress with high lethality. The agent was first described in 1957 and, since then, knowledge about the pathogen itself, and its interactions with the host, has increased continuously. This is, in part, due to the fact that experimental infections can be studied in the natural host. However, the fact that most commercial pigs are colonized by this pathogen has hampered the applicability of knowledge gained under experimental conditions. In addition, several factors are involved in development of disease, and these have often been studied individually. In a DISCONTOOLS initiative, members from science, industry and clinics exchanged their expertise and empirical observations and identified the major gaps in knowledge. This review sums up published results and expert opinions, within the fields of pathogenesis, epidemiology, transmission, immune response to infection, as well as the main means of prevention, detection and control. The gaps that still remain to be filled are highlighted, and present as well as future challenges in the control of this disease are addressed.
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a computational strategy for the search of regulatory small rnas in actinobacillus Pleuropneumoniae
RNA, 2016Co-Authors: Ciro Cesar Rossi, Paul R. Langford, Janine T. Bossé, Adam A Witney, Kate Gould, Denise Mara Soares BazzolliAbstract:Bacterial regulatory small RNAs (sRNAs) play important roles in gene regulation and are frequently connected to the expression of virulence factors in diverse bacteria. Only a few sRNAs have been described for Pasteurellaceae pathogens and no in-depth analysis of sRNAs has been described for Actinobacillus Pleuropneumoniae, the causative agent of Porcine Pleuropneumonia, responsible for considerable losses in the swine industry. To search for sRNAs in A. Pleuropneumoniae, we developed a strategy for the computational analysis of the bacterial genome by using four algorithms with different approaches, followed by experimental validation. The coding strand and expression of 17 out of 23 RNA candidates were confirmed by Northern blotting, RT-PCR, and RNA sequencing. Among them, two are likely riboswitches, three are housekeeping regulatory RNAs, two are the widely studied GcvB and 6S sRNAs, and 10 are putative novel trans-acting sRNAs, never before described for any bacteria. The latter group has several potential mRNA targets, many of which are involved with virulence, stress resistance, or metabolism, and connect the sRNAs in a complex gene regulatory network. The sRNAs identified are well conserved among the Pasteurellaceae that are evolutionarily closer to A. Pleuropneumoniae and/or share the same host. Our results show that the combination of newly developed computational programs can be successfully utilized for the discovery of novel sRNAs and indicate an intricate system of gene regulation through sRNAs in A. Pleuropneumoniae and in other Pasteurellaceae, thus providing clues for novel aspects of virulence that will be explored in further studies.
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iceapl1 an integrative conjugative element related to icehin1056 identified in the pig pathogen actinobacillus Pleuropneumoniae
Frontiers in Microbiology, 2016Co-Authors: Janine T. Bossé, Andrew N. Rycroft, Brendan W. Wren, Roberto Fernandez Crespo, Roy R Chaudhuri, Jon Rogers, Matthew T G Holden, Duncan J Maskell, Alexander W Tucker, Paul R. LangfordAbstract:ICEApl1 was identified in the whole genome sequence of MIDG2331, a tetracycline-resistant (MIC = 8 mg/L) serovar 8 clinical isolate of Actinobacillus Pleuropneumoniae, the causative agent of Porcine Pleuropneumonia. PCR amplification of virB4, one of the core genes involved in conjugation, was used to identify other A. Pleuropneumoniae isolates potentially carrying ICEApl1. MICs for tetracycline were determined for virB4 positive isolates, and shotgun whole genome sequence analysis was used to confirm presence of the complete ICEApl1. The sequence of ICEApl1 is 56083 bp long and contains 67 genes including a Tn10 element encoding tetracycline resistance. Comparative sequence analysis was performed with similar integrative conjugative elements (ICEs) found in other members of the Pasteurellaceae. ICEApl1 is most similar to the 59393 bp ICEHin1056, from Haemophilus influenzae strain 1056. Although initially identified only in serovar 8 isolates of A. Pleuropneumoniae (31 from the UK and 1 from Cyprus), conjugal transfer of ICEApl1 to representative isolates of other serovars was confirmed. All isolates carrying ICEApl1 had a MIC for tetracycline of 8 mg/L. This is, to our knowledge, the first description of an ICE in A. Pleuropneumoniae, and the first report of a member of the ICEHin1056 subfamily in a non-human pathogen. ICEApl1 confers resistance to tetracycline, currently one of the more commonly used antibiotics for treatment and control of Porcine Pleuropneumonia.
Yung-fu Chang - One of the best experts on this subject based on the ideXlab platform.
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polymorphism analysis of the apxia gene of actinobacillus Pleuropneumoniae serovar 5 isolated in swine herds from brazil
PLOS ONE, 2018Co-Authors: Lucas Fernando Dos Santos, Yung-fu Chang, Richard Costa Polveiro, Thalita Scatamburlo Moreira, Pedro Marcus Pereira Vidigal, Maria Aparecida Scatamburlo MoreiraAbstract:The bacterium Actinobacillus Pleuropneumoniae is the etiological agent of Contagious Porcine Pleuropneumonia, a disease responsible for economic losses in the swine industry worldwide. A. Pleuropneumoniae is capable of producing proteinaceous exotoxins responsible for inducing hemorrhagic lesions, one of which is ApxI. Few studies have conducted an in-depth evaluation of polymorphisms of the nucleotides that make up the ApxI toxin gene. Here we analyze the polymorphisms of the apxIA gene region of A. Pleuropneumoniae serovar 5 isolated from swine in different regions in Brazil and report the results of molecular sequencing and phylogenetic analysis. Analysis of the apxIA gene in 60 isolates revealed the presence of genetic diversity and variability. The polymorphisms in the nucleotide sequences determined the grouping of the Brazilian sequences and five more sequences from the GenBank database into 14 different haplotypes, which formed three main groups and revealed the presence of mutations in the nucleotide sequences. The estimation of selection pressures suggests the occurrence of genetic variations by positive selective pressure on A. Pleuropneumoniae in large groups of animals in relatively small spaces. These conditions presumably favor the horizontal dissemination of apxIA gene mutations within bacterial populations with host reservoirs. As a result, the same serovar can demonstrate different antigenic capacities due to mutations in the apxIA gene. These alterations in sequences of the apxIA gene could occur in other areas of countries with intense swine production, which could lead to differences in the pathogenicity and immunogenicity of each serovar and have implications for the clinical status or diagnosis of A. Pleuropneumoniae.
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a trivalent apx fusion protein delivered by e coli outer membrane vesicles induce protection against actinobacillus Pleuropneumoniae of serotype 1 and 7 challenge in a murine model
PLOS ONE, 2018Co-Authors: Qin Zhao, Yung-fu Chang, Xintian Wen, Yiping Wen, Xiaobo Huang, Yong Huang, Qigui Yan, Xinfeng Han, Sanjie CaoAbstract:Actinobacillus Pleuropneumoniae (APP) causes serious economic losses in the swine industry, and is the etiologic agent of Porcine Pleuropneumonia. In this study we have engineered a trivalent Apx fusion protein enclosed in outer membrane vesicles (Apxr-OMV) and studied its immunoprotective efficacy against APP serotypes 1 and 7 challenge in mice. The results showed that the IgG levels in the Apxr-OMVs immune group were significantly higher than those of the negative control (P < 0.05). Up-regulation of both Th1 (IFN-γ, IL-2) and Th2 (IL-4) cytokines were detected in splenocytes of Apxr-OMVs immune group. The survival rates 87.5% and 62.5% were observed against APP strain 1516 of serotype 7 and APP strain 2701 of serotype 1 in the groups of Apxr-OMVs immune group, respectively. Histopathological lesions of the pulmonary structure alveoli were found to be minimal in APX-OMV group challenged with APP serotypes 1 and 7. These results strongly indicated that engineered OMVs could effectively induce specific humoral or cellular immune responses. Moreover, Apxr-OMVs used as novel vaccine provides cross-protective immunity against different serotype 1 and 7 of APP infection in a mouse model. In contrast, the OMV-empty and PBS as negative controls or inactivated strain of APP-2701 and APP-1516 as positive controls for the animal study cannot provide protection or cross-protection.
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molecular analysis of the actinobacillus Pleuropneumoniae rtx toxin iii gene cluster
DNA and Cell Biology, 1993Co-Authors: Yung-fu Chang, M A Dinpow, Sang J Shin, Donald H LeinAbstract:ABSTRACT Actinobacillus Pleuropneumonia strains that secrete three different exotoxins (ApxI, ApxII, and ApxIII) have been implicated in the etiology of Porcine Pleuropneumonia. To understand the role of these toxins in the pathogenesis of this disease, we have previously reported the cloning of the hemolysin gene (apxII) (Chang et al., 1989a), which encodes a 110-kD polypeptide with hemolytic and cytotoxic activity. To clone the third toxin gene (apxIII), a new genomic library using A. Pleuropneumoniae serotype 2 chromosomal DNA was constructed. A series of five overlapping recombinant phage clones carrying the gene (apxIII) for this 120-kD antigen were identified using a DNA probe containing sequences from the Pasteurella haemolytica lktBD genes. Sequence analysis of a region of the cloned DNA reveals four open reading frames encoding proteins with predicted masses of 20.4, 112.5, 80.3, and 54.7 kD. These genes, designated apxIIC, apxIIIA, apxIIIB, and apxIIID, respectively, are similar in sequence to t...