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Janet I Macinnes - One of the best experts on this subject based on the ideXlab platform.
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differential expression of putative adhesin genes of Actinobacillus suis grown in in vivo like conditions
Veterinary Microbiology, 2016Co-Authors: Adina R Bujold, Mario Jacques, Josee Labrie, Janet I MacinnesAbstract:Abstract Actinobacillus suis is an opportunistic pathogen that resides in the tonsils of the soft palate of swine. Unknown stimuli can cause this organism to invade the host, resulting in septicaemia and sequelae including death. To better understand its pathogenesis, the expression of several adhesin genes was evaluated by semi-quantitative real-time PCR in A. suis grown in conditions that mimic the host environment, including different nutrient and oxygen levels, exponential and stationary phases of growth, and in the presence of the stress hormone epinephrine. Fifty micromolar epinephrine did not affect the growth rate or expression of A. suis adhesin genes, but there was a significant growth phase effect for many genes. Most adhesin genes were also differentially expressed during anoxic static growth or aerobic growth, and in this study, all genes were differentially expressed in either exponential or stationary phase. Based on the time*treatment interactions observed in the anoxic study, a model of persistence of A. suis in the host environment in biofilm and planktonic states is proposed. Biofilm dynamics were further studied using wild type and isogenic mutants of the type IVb pilin (Δ flp1) , the OmpA outer membrane protein ( ΔompA) , and the fibronectin-binding ( ΔcomE1) genes. Disruption of these adhesin genes affected the early stages of biofilm formation, but in most cases, biofilm formation of the mutant strains was similar to that of the wild type by 24 h of incubation. We postulate that other adhesins may have overlapping functions that can compensate for those of the missing adhesins.
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attachment of Actinobacillus suis h91 0380 and its isogenic adhesin mutants to extracellular matrix components of the tonsils of the soft palate of swine
Infection and Immunity, 2016Co-Authors: Adina R Bujold, Janet I MacinnesAbstract:ABSTRACT Tonsils conduct immune surveillance of antigens entering the upper respiratory tract. Despite their immunological function, they are also sites of persistence and invasion of bacterial pathogens. Actinobacillus suis is a common resident of the tonsils of the soft palate in pigs, but under certain circumstances it can invade, causing septicemia and related sequelae. Twenty-four putative adhesins are predicted in the A. suis genome, but to date, little is known about how they might participate in colonization or invasion. To better understand these processes, swine tonsil lysates were characterized by mass spectrometry. Fifty-nine extracellular matrix (ECM) proteins were identified, including small leucine-rich proteoglycans, integrins, and other cell surface receptors. Additionally, attachment of the wild type and 3 adhesin mutants to 5 ECM components was evaluated. Exponential cultures of wild-type A. suis adhered significantly more than stationary cultures to all ECM components studied except collagen I. During exponential growth, the A. suis Δ flp1 mutant attached less to collagen IV while the Δ ompA mutant attached less to all ECMs. The Δ comE1 strain attached less to collagen IV, fibronectin, and vitronectin during exponential growth and exhibited differential attachment to collagen I over short adherence time points. These results suggest that Flp1, OmpA, and ComE1 are important during early stages of attachment to ECM components found in tonsils, which supports the notion that other adhesins have compensatory effects during later stages of attachment.
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Identification of putative adhesins of Actinobacillus suis and their homologues in other members of the family Pasteurellaceae.
BMC research notes, 2015Co-Authors: Adina R Bujold, Janet I MacinnesAbstract: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).
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validation of reference genes for quantitative real time pcr qpcr analysis of Actinobacillus suis
BMC Research Notes, 2015Co-Authors: Adina R Bujold, Janet I MacinnesAbstract:Quantitative real-time PCR is a valuable tool for evaluating bacterial gene expression. However, in order to make best use of this method, endogenous reference genes for expression data normalisation must first be identified by carefully validating the stability of expression under experimental conditions. Therefore, the objective of this study was to validate eight reference genes of the opportunistic swine pathogen, Actinobacillus suis, grown in aerobic cultures with (Epinephrine) or without (Aerobic) epinephrine in the growth medium and in anoxic static cultures (Anoxic), and sampled during exponential and stationary phases. Using the RefFinder tool, expression data were analysed to determine whether comprehensive stability rankings of selected reference genes varied with experimental design. When comparing Aerobic and Epinephrine cultures by growth phase, pyk and rpoB were both among the most stably expressed genes, but when analysing both growth phases together, only pyk remained in the top three rankings. When comparing Aerobic and Anoxic samples, proS ranked among the most stable genes in exponential and stationary phase data sets as well as in combined rankings. When analysing the Aerobic, Epinephrine, and Anoxic samples together, only gyrA ranked consistently among the top three most stably expressed genes during exponential and stationary growth as well as in combined rankings; the rho gene ranked as least stably expressed gene in this data set. Reference gene stability should be carefully assessed with the design of the experiment in mind. In this study, even the commonly used reference gene 16S rRNA demonstrated large variability in stability depending on the conditions studied and how the data were analysed. As previously suggested, the best approach may be to use a geometric mean of multiple genes to normalise qPCR results. As researchers continue to validate reference genes for various organisms in multiple growth conditions and sampling time points, it may be possible to make informed predictions as to which genes may be most suitable to validate for a given experimental design, but in the meantime, the reference genes used to normalise qPCR data should be selected with caution.
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serotype o2 strain Actinobacillus suis h91 0380 a virulent complete genome sequence of
2013Co-Authors: Andrew M Kropinski, Janet I Macinnes, Joanne Mackinnon, John H E Nash, Adina R BujoldAbstract:II optical map (9). The gaps were closed bylong-rangePCRandprimerwalking.Usingtheseapproaches,asingle contig totaling 2,484,940 bp was assembled and anno-tated using the NCBI automated prokaryotic genome annota-tion pipeline (http://www.ncbi.nlm.nih.gov/genomes/static/Pipeline.html); further analysis was done using RAST (1). A305-bp region flanked by poly(A) repeats was not able to be se-quenced despite numerous attempts.The
Marcelo Gottschalk - One of the best experts on this subject based on the ideXlab platform.
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characterization of colonization deficient mutants of Actinobacillus suis
Veterinary Microbiology, 2010Co-Authors: Shivani Ojha, Marcelo Gottschalk, Sonia Lacouture, Janet I MacinnesAbstract:Abstract Actinobacillus suis is an important opportunistic pathogen of swine that can cause disease in pigs of all ages, especially in high-health status herds. Although A. suis shares many virulence factors in common with Actinobacillus pleuropneumoniae and can cause a haemorrhagic pleuropneumonia similar to that caused by A. pleuropneumoniae, A. suis most often causes septicaemia and diseases such as arthritis and meningitis that are sequelae to septicaemia. In a recent signature-tagged transposon mutagenesis study, 30 colonization-essential genes of A. suis were identified. In the current study, the attachment and invasion patterns of strains harboring Tn10 insertions in ompA, pfhaB1, lcbB, and cpxR were evaluated using porcine palatine tonsil organ cultures, the swine kidney epithelial cell line, SK6, and a porcine brain microvascular endothelial cell line, PBMEC/C1-2. All of these mutants attached in lower numbers than wild type to the tonsillar explants and to the SK6 cells. The ompA mutant attached in significantly lower numbers than wild type to the porcine tonsil cells (P = 0.02) and to PBMEC (P = 0.0008) at 60 min time point. As well, the ompA mutant showed significantly greater sensitivity than wild type to chemical stressors and to swine serum. Using fluorescent microscopy, a GST-OmpA fusion protein could be demonstrated to interact with the crypt epithelial cells of porcine palatine tonsil.
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Host-Pathogen Interactions of Actinobacillus pleuropneumoniae with Porcine Lung and Tracheal Epithelial Cells†
Infection and Immunity, 2009Co-Authors: Eliane Auger, Marcelo Gottschalk, John H E Nash, Vincent Deslandes, Mahendrasingh Ramjeet, Irazú Contreras, Josée Harel, Martin Olivier, Mario JacquesAbstract:Host-pathogen interactions are of great importance in understanding the pathogenesis of infectious microorganisms. We developed in vitro models to study the host-pathogen interactions of porcine respiratory tract pathogens using two immortalized epithelial cell lines, namely, the newborn pig trachea (NPTr) and St. Jude porcine lung (SJPL) cell lines. We first studied the interactions of Actinobacillus pleuropneumoniae, an important swine pathogen, using these models. Under conditions where cytotoxicity was absent or low, we showed that A. pleuropneumoniae adheres to both cell lines, stimulating the induction of NF-κB. The NPTr cells consequently secrete interleukin 8, while the SJPL cells do not, since they are deprived of the NF-κB p65 subunit. Cell death ultimately occurs by necrosis, not apoptosis. The transcriptomic profile of A. pleuropneumoniae was determined after contact with the porcine lung epithelial cells by using DNA microarrays. Genes such as tadB and rcpA, members of a putative adhesin locus, and a gene whose product has high homology to the Hsf autotransporter adhesin of Haemophilus influenzae were upregulated, as were the genes pgaBC, involved in biofilm biosynthesis, while capsular polysaccharide-associated genes were downregulated. The in vitro models also proved to be efficient with other swine pathogens, such as Actinobacillus suis, Haemophilus parasuis, and Pasteurella multocida. Our results demonstrate that interactions of A. pleuropneumoniae with host epithelial cells seem to involve complex cross talk which results in regulation of various bacterial genes, including some coding for putative adhesins. Furthermore, our data demonstrate the potential of these in vitro models in studying the host-pathogen interactions of other porcine respiratory tract pathogens.
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prevalence of Actinobacillus pleuropneumoniae Actinobacillus suis haemophilus parasuis pasteurella multocida and streptococcus suis in representative ontario swine herds
Canadian Journal of Veterinary Research-revue Canadienne De Recherche Veterinaire, 2008Co-Authors: Janet I Macinnes, Marcelo Gottschalk, Abdul G Lone, Devon S Metcalf, Shivani Ojha, Thomas Rosendal, Sheila Watson, Robert M FriendshipAbstract:Tonsillar and nasal swabs were collected from weanling pigs in 50 representative Ontario swine herds and tested for the presence of 5 important bacterial upper respiratory tract pathogens. All but 1 herd (2%) tested positive for Streptococcus suis by polymerase chain reaction (PCR); 48% of herds were S. suis serovar 2, 1/2 positive. In all but 2 herds there was evidence of Haemophilus parasuis infection. In contrast, toxigenic strains of Pasteurella multocida were detected by a P. multocida — enzyme-linked immunosorbant assay (PMT-ELISA) in only one herd. Seventy-eight percent of the herds were diagnosed positive for Actinobacillus pleuropneumoniae by apxIV PCR. Sera from finishing pigs on the same farms were also collected and tested by ELISA for the presence of A. pleuropneumoniae antibodies. Seventy percent of the herds tested had evidence of antibodies to A. pleuropneumoniae including serovars 1–9–11 (2%), 2 (4%), 3–6–8–15 (15%), 5 (6%), 4–7 (26%), and 12 (17%). This likely represents a shift from previous years when infection with A. pleuropneumoniae serovars 1, 5, and 7 predominated. At least 16% and possibly as many as 94% of the herds tested were Actinobacillus suis positive; only 3 of the 50 herds were both A. pleuropneumoniae and A. suis negative as judged by the absence of a positive PCR test for apxII. Taken together, these data suggest that over the past 10 years, there has been a shift in the presence of pathogenic bacteria carried by healthy Ontario swine with the virtual elimination of toxigenic strains of P. multocida and a move to less virulent A. pleuropneumoniae serovars. As well, there appears to be an increase in prevalence of S. suis serovar 2, 1/2, but this may be a reflection of the use of a more sensitive detection method.
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serologic profile of a cohort of pigs and antibody response to an autogenous vaccine for Actinobacillus suis
Veterinary Research, 2001Co-Authors: Lise Lapointe, Sonia Lacouture, Sylvie Dallaire, Marcelo GottschalkAbstract:Profil serologique chez une cohorte de porcs et reponse humorale a un autovaccin pour Actinobacillus suis. Actinobacillus suis est generalement considere comme un agent pathogene opportuniste chez le porc. Toutefois, en Amerique du Nord, une augmentation de la prevalence des signes cliniques associes a A. suis a ete notee recemment dans des troupeaux de haut statut sanitaire. Les objectifs de cette etude etaient d'evaluer la cinetique des anticorps chez des porcs provenant d'un troupeau dans lequel on observait des signes cliniques associes a A. suis et d'evaluer la reponse humorale suite a l'administration d'un autovaccin chez des cochettes. Un ELISA utilisant un extrait salin a chaud et formalinise d'une souche isolee de cas clinique comme antigene de surface a ete standardise. Cet ELISA a ete utilise pour evaluer de facon comparative les variations des taux d'anticorps pour A. suis dans differents groupes de porcs. Le troupeau selectionne pour le profil serologique etait negatif pour l'infection a Actinobacillus pleuropneumoniae et demontrait des signes cliniques associes a A. suis, chez les porcs de 16 a 19 semaines d'âge. Des prises de sang ont ete effectuees sur une cohorte de 20 porcs a 5, 8, 12, et 16 semaines d'âge. Le niveau d'anticorps le plus bas a ete observe entre 8 et 12 semaines d'âge, refletant vraisemblablement une baisse de l'immunite d'origine maternelle. Une augmentation importante du taux d'anticorps est survenue a 16 semaines d'âge, approximativement au moment ou les signes cliniques etaient observes dans ce troupeau. L'administration d'un autovaccin aux cochettes a induit une augmentation du taux d'anticorps meme si celui-ci etait deja eleve avant la vaccination. L'amplitude de la reponse a la vaccination etait d'autant plus elevee que le taux d'anticorps etait faible avant la premiere vaccination. Le test ELISA semble detecter la chaine O des LPS.
Adina R Bujold - One of the best experts on this subject based on the ideXlab platform.
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differential expression of putative adhesin genes of Actinobacillus suis grown in in vivo like conditions
Veterinary Microbiology, 2016Co-Authors: Adina R Bujold, Mario Jacques, Josee Labrie, Janet I MacinnesAbstract:Abstract Actinobacillus suis is an opportunistic pathogen that resides in the tonsils of the soft palate of swine. Unknown stimuli can cause this organism to invade the host, resulting in septicaemia and sequelae including death. To better understand its pathogenesis, the expression of several adhesin genes was evaluated by semi-quantitative real-time PCR in A. suis grown in conditions that mimic the host environment, including different nutrient and oxygen levels, exponential and stationary phases of growth, and in the presence of the stress hormone epinephrine. Fifty micromolar epinephrine did not affect the growth rate or expression of A. suis adhesin genes, but there was a significant growth phase effect for many genes. Most adhesin genes were also differentially expressed during anoxic static growth or aerobic growth, and in this study, all genes were differentially expressed in either exponential or stationary phase. Based on the time*treatment interactions observed in the anoxic study, a model of persistence of A. suis in the host environment in biofilm and planktonic states is proposed. Biofilm dynamics were further studied using wild type and isogenic mutants of the type IVb pilin (Δ flp1) , the OmpA outer membrane protein ( ΔompA) , and the fibronectin-binding ( ΔcomE1) genes. Disruption of these adhesin genes affected the early stages of biofilm formation, but in most cases, biofilm formation of the mutant strains was similar to that of the wild type by 24 h of incubation. We postulate that other adhesins may have overlapping functions that can compensate for those of the missing adhesins.
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attachment of Actinobacillus suis h91 0380 and its isogenic adhesin mutants to extracellular matrix components of the tonsils of the soft palate of swine
Infection and Immunity, 2016Co-Authors: Adina R Bujold, Janet I MacinnesAbstract:ABSTRACT Tonsils conduct immune surveillance of antigens entering the upper respiratory tract. Despite their immunological function, they are also sites of persistence and invasion of bacterial pathogens. Actinobacillus suis is a common resident of the tonsils of the soft palate in pigs, but under certain circumstances it can invade, causing septicemia and related sequelae. Twenty-four putative adhesins are predicted in the A. suis genome, but to date, little is known about how they might participate in colonization or invasion. To better understand these processes, swine tonsil lysates were characterized by mass spectrometry. Fifty-nine extracellular matrix (ECM) proteins were identified, including small leucine-rich proteoglycans, integrins, and other cell surface receptors. Additionally, attachment of the wild type and 3 adhesin mutants to 5 ECM components was evaluated. Exponential cultures of wild-type A. suis adhered significantly more than stationary cultures to all ECM components studied except collagen I. During exponential growth, the A. suis Δ flp1 mutant attached less to collagen IV while the Δ ompA mutant attached less to all ECMs. The Δ comE1 strain attached less to collagen IV, fibronectin, and vitronectin during exponential growth and exhibited differential attachment to collagen I over short adherence time points. These results suggest that Flp1, OmpA, and ComE1 are important during early stages of attachment to ECM components found in tonsils, which supports the notion that other adhesins have compensatory effects during later stages of attachment.
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RESEARCH ARTICLE Identification of putative adhesins
2016Co-Authors: Adina R BujoldAbstract:of Actinobacillus suis and their homologues in other members of the family Pasteurellacea
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Identification of putative adhesins of Actinobacillus suis and their homologues in other members of the family Pasteurellaceae.
BMC research notes, 2015Co-Authors: Adina R Bujold, Janet I MacinnesAbstract: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).
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validation of reference genes for quantitative real time pcr qpcr analysis of Actinobacillus suis
BMC Research Notes, 2015Co-Authors: Adina R Bujold, Janet I MacinnesAbstract:Quantitative real-time PCR is a valuable tool for evaluating bacterial gene expression. However, in order to make best use of this method, endogenous reference genes for expression data normalisation must first be identified by carefully validating the stability of expression under experimental conditions. Therefore, the objective of this study was to validate eight reference genes of the opportunistic swine pathogen, Actinobacillus suis, grown in aerobic cultures with (Epinephrine) or without (Aerobic) epinephrine in the growth medium and in anoxic static cultures (Anoxic), and sampled during exponential and stationary phases. Using the RefFinder tool, expression data were analysed to determine whether comprehensive stability rankings of selected reference genes varied with experimental design. When comparing Aerobic and Epinephrine cultures by growth phase, pyk and rpoB were both among the most stably expressed genes, but when analysing both growth phases together, only pyk remained in the top three rankings. When comparing Aerobic and Anoxic samples, proS ranked among the most stable genes in exponential and stationary phase data sets as well as in combined rankings. When analysing the Aerobic, Epinephrine, and Anoxic samples together, only gyrA ranked consistently among the top three most stably expressed genes during exponential and stationary growth as well as in combined rankings; the rho gene ranked as least stably expressed gene in this data set. Reference gene stability should be carefully assessed with the design of the experiment in mind. In this study, even the commonly used reference gene 16S rRNA demonstrated large variability in stability depending on the conditions studied and how the data were analysed. As previously suggested, the best approach may be to use a geometric mean of multiple genes to normalise qPCR results. As researchers continue to validate reference genes for various organisms in multiple growth conditions and sampling time points, it may be possible to make informed predictions as to which genes may be most suitable to validate for a given experimental design, but in the meantime, the reference genes used to normalise qPCR data should be selected with caution.
Peter Kuhnert - One of the best experts on this subject based on the ideXlab platform.
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mesenteric lymphangitis and sepsis due to rtx toxin producing Actinobacillus spp in 2 foals with hypothyroidism dysmaturity syndrome
Veterinary Pathology, 2012Co-Authors: Peter Kuhnert, Christiane V Lohr, Ulf Polster, Axel Karger, Fred R. Rurangirwa, Jens Peter TeifkeAbstract:Actinobacillus suis-like organisms (ASLOs) have been isolated from the genital, respiratory, and digestive tracts of healthy adult horses, horses with respiratory disease, and septic foals. Two foals with congenital hypothyroidism-dysmaturity syndrome from separate farms developed ASLO infection. At necropsy, both had contracted carpal flexor tendons, thyroid hyperplasia, and thrombotic and necrotizing mesenteric lymphangitis and lymphadenitis; one foal also had mandibular prognathism. Numerous ASLOs were isolated from tissues from both foals, including intestine. Biochemical testing and mass spectrometric analysis of the two Actinobacillus isolates did not allow unequivocal identification. Comparative genetic analysis was done on these and similar isolates, including phylogeny based on 16S rRNA, rpoB and recN genes, as well as RTX (repeat in toxin) toxin typing of apxIA-apxIVA and aqxA genes. One isolate was identified as Actinobacillus suis sensu stricto, based on the presence of apxIA and apxIIA but not aqxA, whereas the other isolate had aqxA but neither apxIA nor apxIIA, consistent with A equuli ssp haemolyticus. Based on genotypic analysis of the isolates included for comparison, 3 of 3 equine ASLOs and 2 of 5 A equuli isolates were reclassified as A equuli subsp haemolyticus, emphasizing the importance of toxin genotyping in accurate classification of actinobacilli.
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phylogenetic relationship of equine Actinobacillus species and distribution of rtx toxin genes among clusters
Veterinary Research, 2003Co-Authors: Peter Kuhnert, Helene Berthoud, Henrik Christensen, Magne BisgaardAbstract:Equine Actinobacillus species were analysed phylogenetically by 16S rRNA gene (rrs) sequencing focusing on the species Actinobacillus equuli, which has recently been subdivided into the non-haemolytic A. equuli subsp. equuli and the haemolytic A. equuli subsp. haemolyticus. In parallel we determined the profile for RTX toxin genes of the sample of strains by PCR testing for the presence of the A. equuli haemolysin gene aqx, and the toxin genes apxI, apxII, apxIII and apxIV, which are known in porcine pathogens such as Actinobacillus pleuropneumoniae and Actinobacillus suis. The rrs-based phylogenetic analysis revealed two distinct subclusters containing both A. equuli subsp. equuli and A. equuli subsp. haemolyticus distributed through both subclusters with no correlation to taxonomic classification. Within one of the rrs-based subclusters containing the A. equuli subsp. equuli type strain, clustered as well the porcine Actinobacillus suis strains. This latter is known to be also phenotypically closely related to A. equuli. The toxin gene analysis revealed that all A. equuli subsp. haemolyticus strains from both rrs subclusters specifically contained the aqx gene while the A. suis strains harboured the genes apxI and apxII. The aqx gene was found to be specific for A. equuli subsp. haemolyticus, since A. equuli subsp. equuli contained no aqx nor any of the other RTX genes tested. The specificity of aqx for the haemolytic equine A. equuli and ApxI and ApxII for the porcine A. suis indicates a role of these RTX toxins in host species predilection of the two closely related species of bacterial pathogens and allows PCR based diagnostic differentiation of the two.
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Host cell specific activity of RTX toxins from haemolytic Actinobacillus equuli and Actinobacillus suis.
Veterinary microbiology, 2003Co-Authors: Peter Kuhnert, Helene Berthoud, R StraubAbstract:We assessed and compared host cell specificity of the haemolytic and cytotoxic activity of the RTX toxins from Actinobacillus equuli, an equine pathogen, and Actinobacillus suis, which is pathogenic for pigs. The two bacterial species are closely related, phenotypically as well as phylogenetically, sharing the same 16S rRNA gene sequence. Both species contain specific protein toxins from the family of pore-forming RTX toxins, however, the two species differ in their RTX toxin profiles. Haemolytic A. equuli contains the operon for the Aqx toxin, whereas A. suis harbours genes for ApxI and ApxII. We tested the toxic activity of the corresponding proteins on erythrocytes as well as on lymphocytes isolated from horse and pig blood. The strength of the haemolytic activity for each of the toxins was independent of the origin of erythrocytes. When testing cytotoxic activity, the Aqx protein showed a higher toxic effect for horse lymphocytes than for porcine lymphocytes. On the other hand, ApxI and ApxII showed a strong cytotoxic effect on porcine lymphocytes and a reduced toxicity for horse lymphocytes; the toxicity of ApxII was generally much lower than ApxI. Our results indicate a host species specificity of the toxic activity of RTX toxins Aqx of A. equuli and ApxI and ApxII of A. suis.
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analysis of non porcine isolates of Actinobacillus suis
Veterinary Microbiology, 2002Co-Authors: Marie Eve Jeannotte, Peter Kuhnert, Durda Slavic, Joachim Frey, Janet I MacinnesAbstract:Twenty-four Actinobacillus suis isolates obtained from several species of non-porcine mammals were compared to the representative porcine strains, ATCC 15557 (serotype O1) and H89-1173 (serotype O2), by O serotyping, DNA fingerprinting, PCR amplification of apxICA, apxIICA and apxIIICA toxin genes and by rrs (16S rRNA) gene sequencing. Only two strains, both equine, reacted with O1 antiserum while two others, one canine and the other feline, reacted with O2 antiserum. One equine strain reacted weakly with both antisera. No amplification of apx genes was found with the non-porcine O1 or the "not O1/O2" strains but amplification of the apxICA and apxIICA genes was observed with the two O2 strains. In addition, these two O2 strains had both BamHI and BglII fingerprints that were very similar to the porcine O2 reference strain, H89-1173 and rrs gene sequences that were identical to the A. suis reference strain ATCC 15557. Taken together, these data suggest that although many non-porcine A. suis isolates are not A. suis (sensu stricto), some isolates are genotypically as well as phenotypically similar to A. suis.
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Apx toxins in Pasteurellaceae species from animals.
Veterinary Microbiology, 2000Co-Authors: Alain Schaller, Peter Kuhnert, V. A. De La Puente-redondo, Jacques NicoletAbstract:Abstract Pasteurellaceae species particularly of porcine origin which are closely related to Actinobacillus pleuropneumoniae were analyzed for the presence of analogues to the major A. pleuropneumoniae RTX toxin genes, apxICABD , apxIICA and apxIIICABD and for their expression. Actinobacillus suis contains both apxICABD var. suis and apxIICA var. suis operons and was shown to produce ApxI and ApxII toxin. Actinobacillus rossii contained the operons apxIICA var. rossii and apxIIICABD var. rossii . However, only the toxin ApxII and not ApxIII could be detected in cultures of A. rossii . The Apx toxins found in A. suis and A. rossi may play a role in virulence of these pathogens. Actinobacillus lignieresii , which was included since it is phylogenetically very closely related to A. pleuropneumoniae , was found to contain a full apxICABD var. lign. operon which however lacks the −35 and −10 boxes in the promoter sequences. As expected from these results, no expression of ApxI was detected in A. lignieresii grown under standard culture conditions. Actinobacillus seminis , Actinobacillus equuli , Pasteurella aerogenes , Pasteurella multocida , Haemophilus parasuis , and also Mannheimia ( Pasteurella ) haemolytica , which is known to secrete leukotoxin, were all shown to be devoid of any of the apx toxin genes and did not produce ApxI, ApxII or ApxIII toxin proteins. However, proteins of slightly lower molecular mass than ApxI, ApxII and ApxIII which showed limited cross-reactions with monospecific, polyclonal anti-ApxI, anti-ApxII and anti-ApxIII were detected on immunoblot analysis of A. equuli , A. seminis and P. aerogenes . The presence of Apx toxins and proteins that imunologically cross react with Apx toxins in porcine Actinobacillus species other than A. pleuropneumoniae can be expected to interfere with serodiagnosis of porcine pleuropneumonia.
Anna Monteiro Correia Lima Ribeiro - One of the best experts on this subject based on the ideXlab platform.
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toxinas e perfil proteico de amostras de Actinobacillus suis provenientes de planteis suinos norte americanos
Ciencia Rural, 2010Co-Authors: Rafael Silveira Carreon, Simone Oliveira, Rone Cardoso, Joao Helder Frederico De Faria Naves, John Tomaszewski, Anna Monteiro Correia Lima RibeiroAbstract:Actinobacillus suis (A. suis) has arisen as a great threat to the North American hog herds. The clinical symptoms and lesions are particularly variable and may resemble the same caused by other pathogenic organisms, such as Actinobacillus pleuropneumoniae (App), which can similarly lead to the production of the toxins ApxI and ApxII. This study aimed to confirm the production of the toxins ApxI and ApxII, as well as, to investigate the production of toxins that are genetically similar to ApxIII, and analyze total protein to verify whether there is any similarity among the isolated samples obtained from different North American hog herds. In this study, all the strains of A. suis were positive for the genes that codify the toxins ApxI and ApxII using the multiplex polymerase chain reaction (PCR-multiplex) method; and total protein from 70 samples of A. suis, obtained from different North American hog herds, were analyzed through denaturing polyacrylamide gel electrophoresis (SDS-PAGE), and were identical. The electrophoretic similarity observed among total protein of the analyzed bacteria indicates that there is the possibility of existing a cross protection in case of developing a probable universal vaccine with the antigens of A. suis.
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Toxinas e perfil protéico de amostras de Actinobacillus suis provenientes de plantéis suínos norte-americanos Toxins and proteic profile of Actinobacillus suis samples from North American hog herds
Universidade Federal de Santa Maria, 2010Co-Authors: Rafael Silveira Carreon, Rone Cardoso, Joao Helder Frederico De Faria Naves, John Tomaszewski, Simone Rodrigues Oliveira, Anna Monteiro Correia Lima RibeiroAbstract:Actinobacillus suis (A.suis) surgiu como uma grande ameaça aos plantéis suínos norte-americanos. Os sinais clínicos e as lesões são particularmente variáveis e podem lembrar aquelas causadas por outros organismos, como o Actinobacillus pleuropneumoniae (App), podendo ter como causa a similaridade na produção das toxinas ApxI e ApxII. Os objetivos do estudo foram confirmar a produção das toxinas ApxI e ApxII, investigar a produção de toxina geneticamente semelhante à Apx III e analisar as proteínas totais, verificando se existe similaridade entre os isolados provenientes de diferentes plantéis de suínos norte-americanos. Neste estudo, todas as cepas de A. suis foram positivas para os genes codificadores das toxinas ApxI e ApxII, usando o método de reação em cadeia de polimerase - multiplex (PCR-multiplex); e as proteínas totais de 70 amostras de A. suis, oriundos de diferentes plantéis suínos norte-americanos, foram analisadas por meio de eletroforese em gel de poliacrilaminda desnaturante (SDS-PAGE) e foram idênticas. A similaridade eletroforética observada entre as proteínas totais das bactérias analisadas indica a possibilidade de haver uma proteção cruzada a partir de uma provável vacina universal desenvolvida com esses antígenos para A. suis.Actinobacillus suis (A. suis) has arisen as a great threat to the North American hog herds. The clinical symptoms and lesions are particularly variable and may resemble the same caused by other pathogenic organisms, such as Actinobacillus pleuropneumoniae (App), which can similarly lead to the production of the toxins ApxI and ApxII. This study aimed to confirm the production of the toxins ApxI and ApxII, as well as, to investigate the production of toxins that are genetically similar to ApxIII, and analyze total protein to verify whether there is any similarity among the isolated samples obtained from different North American hog herds. In this study, all the strains of A. suis were positive for the genes that codify the toxins ApxI and ApxII using the multiplex polymerase chain reaction (PCR-multiplex) method; and total protein from 70 samples of A. suis, obtained from different North American hog herds, were analyzed through denaturing polyacrylamide gel electrophoresis (SDS-PAGE), and were identical. The electrophoretic similarity observed among total protein of the analyzed bacteria indicates that there is the possibility of existing a cross protection in case of developing a probable universal vaccine with the antigens of A. suis
