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1.
Curr Microbiol ; 78(1): 55-66, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33145611

RESUMO

Erysipelothrix rhusiopathiae causes swine erysipelas (SE), which results in considerable economic loss on pig farms. During SE outbreaks that occurred sporadically from 2008 to 2011 in Japan, new E. rhusiopathiae strains were isolated with a specific surface protective antigen (Spa)A protein characterized by methionine at position 203 and isoleucine at position 257 (M203/I257 SpaA type). To determine whether strains with the M203/I257 SpaA type are still prevalent in Japan, we collected 79 strains of E. rhusiopathiae from pigs showing various SE symptoms from 2012 to 2019 and classified them based on serovar typing, spaA gene sequence analysis, and lineage typing. We found that the majority of recent E. rhusiopathiae strains (59/79) belonged to the serovar 1a strain, and that the M203/I257 SpaA type (56/59) was predominant continuing from 2008 to 2011. Furthermore, serovar 1a strains with IVb-1 and IVb-2 lineages that had been isolated in specific regions of Japan were no longer local but were found across Japan. The pathogenicity of recent isolates tested in mice was not significantly changed when compared to that of previously isolated strains. Our results suggest that recent SE outbreaks were not due to changes in the SpaA protein or to altered virulence of E. rhusiopathiae but were rather caused by the persistent presence of E. rhusiopathiae with the M203/I257 SpaA type.


Assuntos
Erysipelothrix , Erisipela Suína , Animais , Erysipelothrix/genética , Japão , Camundongos , Sorogrupo , Suínos , Virulência
2.
Nature ; 483(7391): 623-6, 2012 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-22407319

RESUMO

Many bacterial pathogens can enter various host cells and then survive intracellularly, transiently evade humoral immunity, and further disseminate to other cells and tissues. When bacteria enter host cells and replicate intracellularly, the host cells sense the invading bacteria as damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs) by way of various pattern recognition receptors. As a result, the host cells induce alarm signals that activate the innate immune system. Therefore, bacteria must modulate host inflammatory signalling and dampen these alarm signals. How pathogens do this after invading epithelial cells remains unclear, however. Here we show that OspI, a Shigella flexneri effector encoded by ORF169b on the large plasmid and delivered by the type ΙΙΙ secretion system, dampens acute inflammatory responses during bacterial invasion by suppressing the tumour-necrosis factor (TNF)-receptor-associated factor 6 (TRAF6)-mediated signalling pathway. OspI is a glutamine deamidase that selectively deamidates the glutamine residue at position 100 in UBC13 to a glutamic acid residue. Consequently, the E2 ubiquitin-conjugating activity required for TRAF6 activation is inhibited, allowing S. flexneri OspI to modulate the diacylglycerol-CBM (CARD-BCL10-MALT1) complex-TRAF6-nuclear-factor-κB signalling pathway. We determined the 2.0 Å crystal structure of OspI, which contains a putative cysteine-histidine-aspartic acid catalytic triad. A mutational analysis showed this catalytic triad to be essential for the deamidation of UBC13. Our results suggest that S. flexneri inhibits acute inflammatory responses in the initial stage of infection by targeting the UBC13-TRAF6 complex.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Amidoidrolases/química , Amidoidrolases/metabolismo , Inflamação/imunologia , Inflamação/metabolismo , Shigella flexneri/enzimologia , Shigella flexneri/imunologia , Enzimas de Conjugação de Ubiquitina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Amidoidrolases/genética , Sequência de Aminoácidos , Animais , Ácido Aspártico/metabolismo , Proteína 10 de Linfoma CCL de Células B , Biocatálise , Caspases/metabolismo , Domínio Catalítico/genética , Cristalografia por Raios X , Cisteína/metabolismo , Análise Mutacional de DNA , Diglicerídeos/antagonistas & inibidores , Diglicerídeos/metabolismo , Disenteria Bacilar/microbiologia , Ácido Glutâmico/metabolismo , Glutamina/metabolismo , Células HEK293 , Células HeLa , Histidina/metabolismo , Humanos , Imunidade Inata , Inflamação/enzimologia , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa , NF-kappa B/metabolismo , Proteínas de Neoplasias/metabolismo , Shigella flexneri/genética , Shigella flexneri/patogenicidade , Fator 6 Associado a Receptor de TNF/deficiência , Fator 6 Associado a Receptor de TNF/genética , Fator 6 Associado a Receptor de TNF/metabolismo , Enzimas de Conjugação de Ubiquitina/química , Enzimas de Conjugação de Ubiquitina/genética , Fatores de Virulência/metabolismo
3.
Rev Argent Microbiol ; 50(1): 12-22, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28886933

RESUMO

The objectives of this study were to determine the serovar of a collection of Actinobacillus pleuropneumoniae strains within the 3-6-8-15 cross-reacting group and to analyze their phenotypic and genetic properties. Based on the serological tests, forty-seven field strains of Actinobacillus pleuropneumoniae isolated from lungs with pleuropneumonia lesions in Japan and Argentina were found to be serovars belonging to the 3-6-8-15 cross-reacting group. By using a capsule loci-based PCR, twenty-nine (96.7%) and one (3.3%) from Japan were identified as serovars 15 and 8, respectively, whereas seventeen (100%) from Argentina were identified as serovar 8. The findings suggested that serovars 8 and 15 were prevalent within the 3-6-8-15 cross-reacting group, in Argentina and Japan, respectively. Phenotypic analyses revealed that the protein patterns observed on SDS-PAGE and the lipopolysaccharide antigen detected by immunoblotting of the reference and field strains of serovars 8 and 15 were similar to each other. Genetic (16S rDNA, apxIIA, apxIIIA, cps, cpx genes, apx and omlA patterns) analyses revealed that the apxIIA and apxIIIA genes of the field strains of serovars 8 and 15 were similar to those of the reference strains of serovars 3, 4, 6, 8 and 15. The results obtained in the present study may be useful for the development of more effective vaccines against disease caused by A. pleuropneumoniae by including the homologous antigens to the most prevalent serovars in specific geographical areas.


Assuntos
Infecções por Actinobacillus , Actinobacillus pleuropneumoniae , Doenças dos Suínos , Infecções por Actinobacillus/genética , Infecções por Actinobacillus/veterinária , Actinobacillus pleuropneumoniae/genética , Animais , Argentina , Japão , Suínos , Doenças dos Suínos/genética
4.
Microbiol Immunol ; 60(7): 447-58, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27211905

RESUMO

Apx toxins produced by Actinobacillus pleuropneumoniae are essential components of new generation vaccines. In this study, apxIIA and apxIIIA genes of serovars 2, 3, 4, 6, 8 and 15 were cloned and sequenced. Amino acid sequences of ApxIIA proteins of serovars 2, 3, 4, 6, 8 and 15 were almost identical to those of serovars 1, 5, 7, 9 and 11-13. Immunoblot analysis showed that rApxIIA from serovars 2 and 15 reacts strongly with sera from animals infected with various serovars. Sequence analysis revealed that ApxIIIA proteins has two variants, one in strains of serovar 2 and the other in strains of serovars 3, 4, 6, 8 and 15. A mouse cross-protection study showed that mice actively immunized with rApxIIIA/2 or rApxIIIA/15 are protected against challenge with A. pleuropneumoniae strains of serovars 3, 4, 6, 8, 15, and 2 expressing ApxIII/15 and ApxIII/2, respectively. Similarly, mice passively immunized with rabbit anti-rApxIIIA/2 or anti-rApxIIIA/15 sera were found to be protected against challenge with strains of serovars 2 and 15. Our study revealed antigenic and sequence similarities within ApxIIA and ApxIIIA proteins, which may help in the development of effective vaccines against disease caused by A. pleuropneumoniae.


Assuntos
Actinobacillus pleuropneumoniae/genética , Actinobacillus pleuropneumoniae/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/imunologia , Sorogrupo , Infecções por Actinobacillus/imunologia , Infecções por Actinobacillus/prevenção & controle , Actinobacillus pleuropneumoniae/classificação , Sequência de Aminoácidos , Animais , Anticorpos Antibacterianos/imunologia , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Expressão Gênica , Proteínas Hemolisinas/química , Proteínas Hemolisinas/isolamento & purificação , Imunização , Camundongos , Modelos Moleculares , Conformação Proteica , Domínios Proteicos , Coelhos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/isolamento & purificação , Suínos
5.
Microvasc Res ; 97: 115-23, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25446286

RESUMO

We constructed three-dimensional microvascular bifurcation models using a parent vessel of diameter 10µm and investigated the flow behavior of the red blood cells (RBCs) through bifurcations. We considered symmetric and asymmetric model types. Two cases of equal daughter vessel diameter were employed for the asymmetric models, where the first was 10µm, which is the same as the parent vessel and the second was 7.94µm, which satisfies Murray's law. Simulated blood flow was computed using the lattice Boltzmann method in conjunction with the immersed boundary method for incorporating fluid-membrane interactions between the flow field and deformable RBCs. First, we investigated the flow behavior of a single RBC through microvascular bifurcations. In the case of the symmetric bifurcation, the turning point of the fractional plasma flow wherein the RBC flow changed from one daughter vessel to the other was 0.50. This turning point was however different for asymmetric bifurcations. Additionally, we varied the initial offset of RBCs from the centerline of the parent vessel. The simulation results indicated that the RBCs preferentially flow through the branch of a larger flow ratio. Next, we investigated the distribution characteristics of multiple RBCs. Simulations indicated that the results of the symmetric model were similar to those predicted by a previously published empirical model. On the other hand, results of asymmetric models deviated from those of the symmetric and empirical models. These results suggest that the distribution of RBCs varies according to the bifurcation angle and daughter vessel diameter in a microvascular bifurcation of the size considered.


Assuntos
Simulação por Computador , Eritrócitos/fisiologia , Hemorreologia , Microcirculação , Microvasos/fisiologia , Modelos Cardiovasculares , Análise Numérica Assistida por Computador , Animais , Velocidade do Fluxo Sanguíneo , Humanos , Microvasos/anatomia & histologia , Fluxo Sanguíneo Regional
6.
Nature ; 459(7246): 578-82, 2009 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-19489119

RESUMO

The rapid turnover and exfoliation of mucosal epithelial cells provides an innate defence system against bacterial infection. Nevertheless, many pathogenic bacteria, including Shigella, are able to surmount exfoliation and colonize the epithelium efficiently. Here we show that the Shigella flexneri effector OspE (consisting of OspE1 and OspE2 proteins), which is highly conserved among enteropathogenic Escherichia coli, enterohaemorrhagic E. coli, Citrobacter rodentium and Salmonella strains, reinforces host cell adherence to the basement membrane by interacting with integrin-linked kinase (ILK). The number of focal adhesions was augmented along with membrane fraction ILK by ILK-OspE binding. The interaction between ILK and OspE increased cell surface levels of 1 integrin and suppressed phosphorylation of focal adhesion kinase and paxillin, which are required for rapid turnover of focal adhesion in cell motility. Nocodazole-washout-induced focal adhesion disassembly was blocked by expression of OspE. Polarized epithelial cells infected with a Shigella mutant lacking the ospE gene underwent more rapid cell detachment than cells infected with wild-type Shigella. Infection of guinea pig colons with Shigella corroborated the pivotal role of the OspE-ILK interaction in suppressing epithelial detachment, increasing bacterial cell-to-cell spreading, and promoting bacterial colonization. These results indicate that Shigella sustain their infectious foothold by using special tactics to prevent detachment of infected cells.


Assuntos
Adesão Celular/fisiologia , Adesões Focais/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Shigella flexneri/fisiologia , Animais , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Adesão Celular/efeitos dos fármacos , Polaridade Celular , Colo/microbiologia , Células Epiteliais/citologia , Células Epiteliais/microbiologia , Adesões Focais/efeitos dos fármacos , Cobaias , Células HeLa , Humanos , Integrina beta1/metabolismo , Camundongos , Nocodazol/farmacologia , Fosforilação , Ligação Proteica , Shigella flexneri/patogenicidade , Fatores de Virulência/deficiência , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
7.
Vet Microbiol ; 291: 110030, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38428226

RESUMO

We have analyzed the capsule (CPS) and the lipopolysaccharide O-Antigen (O-Ag) biosynthesis loci of twelve Spanish field isolates of Actinobacillus pleuropneumoniae biovar 2, eleven of them previously typed serologically as serovar 4 and one non-typable (NT) (Maldonado et al., 2009, 2011). These isolates have the common core genes of the type I CPS locus, sharing >98% identity with those of serovar 2. However, the former possesses the O-Ag locus as serovar 4, and the latter possesses the O-Ag locus as serovar 7. The main difference found between the CPS loci of the 11 isolates and that of serovar 2 reference strain S1536 are two deletions, one of an 8 bp sequence upstream of the coding sequence and one of 111 bp sequence at the 5' end of the cps2G gene. The deletion mutations mentioned lead to a defect in the production of CPS in these isolates, which contributed to their previous mis-identification. In order to complement the serotyping of A. pleuropneumoniae in diagnostics and epidemiology, we have developed a multiplex PCR for the comprehensive O-Ag typing of all A. pleuropneumoniae isolates.


Assuntos
Infecções por Actinobacillus , Actinobacillus pleuropneumoniae , Doenças dos Suínos , Animais , Suínos , Sorogrupo , Reação em Cadeia da Polimerase Multiplex/veterinária , Antígenos O/genética , Infecções por Actinobacillus/veterinária , Sorotipagem/veterinária
8.
J Vet Diagn Invest ; 35(6): 766-771, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37542385

RESUMO

Three Actinobacillus pleuropneumoniae isolates from clinical cases of porcine pleuropneumonia were positive by capsular serovar 12-specific PCR assay, but not reactive to antiserum prepared against serovar 12 using the rapid slide agglutination (RSA) test. The isolates were positive for apxIICA, apxIIICA, apxIBD, apxIIIBD, and apxIVA in the PCR toxin gene assay, which is the profile seen in serovars 2, 4, 6, 8, and 15, and reacted with antisera against serovars 3, 6, 8, 15, and 17. Nucleotide sequence analysis revealed that genes involved in the biosynthesis of capsular polysaccharide of the 3 isolates were identical or nearly identical to those of serovar 12. However, genes involved in the biosynthesis of O-polysaccharide of the 3 isolates were highly similar to those of reference strains of serovars 3, 6, 8, 15, 17, and 19. In agreement with results from the RSA test, transmission electron microscopic analysis confirmed the absence of detectable capsular material in the 3 isolates. The existence of nonencapsulated A. pleuropneumoniae serovar K12:O3 would hamper precise serodetection.


Assuntos
Infecções por Actinobacillus , Actinobacillus pleuropneumoniae , Pleuropneumonia , Doenças dos Suínos , Animais , Suínos , Sorogrupo , Actinobacillus pleuropneumoniae/genética , Infecções por Actinobacillus/epidemiologia , Infecções por Actinobacillus/veterinária , Infecções por Actinobacillus/diagnóstico , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/diagnóstico , Pleuropneumonia/epidemiologia , Pleuropneumonia/veterinária , Pleuropneumonia/diagnóstico , Polissacarídeos
9.
J Vet Med Sci ; 85(10): 1131-1135, 2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37612056

RESUMO

Five pigs experimentally infected with Actinobacillus pleuropneumoniae serovar 15 isolated in our previous study were pathologically examined. One pig died at 2 days post inoculation (dpi) and four pigs were euthanized at 7 dpi. Autopsy revealed fibrinohemorrhagic pleuropneumonia in all pigs. Histopathologically, the lesions were characterized by extensive hemorrhage and necrosis, fibrin deposition, and multifocal abscesses composed of numerous neutrophils including oat cells and numerous Gram-negative bacilli. In one survived pig, asteroid body formation was confirmed in the lung. The bacteria within the abscesses and asteroid bodies were immunohistochemically positive for antiserum raised against A. pleuropneumoniae serovar 15. This is the first report describing porcine pleuropneumonia with asteroid bodies in a pig experimentally infected with A. pleuropneumoniae serovar 15.


Assuntos
Infecções por Actinobacillus , Actinobacillus pleuropneumoniae , Mycoplasma , Pleuropneumonia , Doenças dos Suínos , Suínos , Animais , Pleuropneumonia/microbiologia , Pleuropneumonia/veterinária , Sorogrupo , Abscesso/patologia , Abscesso/veterinária , Infecções por Actinobacillus/microbiologia , Infecções por Actinobacillus/veterinária , Doenças dos Suínos/microbiologia , Pulmão/patologia
10.
J Vet Med Sci ; 85(2): 157-162, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36477365

RESUMO

We describe phenotypic and genetic characterization of an atypical Japanese Actinobacillus pleuropneumoniae isolate OT761. Nucleotide sequence analysis revealed that gene clusters involved in capsular polysaccharide and O-polysaccharide (O-PS) biosynthesis of the isolate were nearly identical to those of serovar 2 reference strain. The main difference found between the O-PS loci is the shortening of 31 amino acids from the C terminus of WcaJ in the atypical isolate due to a 93 bp deletion at the 3' end of wcaJ gene. Immunoblot analysis revealed that this isolate could not produce O-PS. Taken together, our results showed that the C-terminal domain of the A. pleuropneumoniae WcaJ plays a critical role in enzyme function of WcaJ involved in the biosynthesis of O-PS.


Assuntos
Infecções por Actinobacillus , Actinobacillus pleuropneumoniae , Doenças dos Suínos , Suínos , Animais , Lipopolissacarídeos , Sorogrupo , Actinobacillus pleuropneumoniae/genética , Infecções por Actinobacillus/veterinária , Polissacarídeos , Sorotipagem/veterinária
11.
Microbiol Immunol ; 56(9): 605-12, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22708916

RESUMO

Here construction of an attenuated mutant of an avian pathogenic Escherichia coli serovar O78 using an allelic exchange procedure is described. The mutant AESN1331, which carries a deletion in the crp gene, lost tryptophan deaminase activity and therefore lacked the ability to produce indole. The mutant strain additionally lacked the ability to adsorb Congo red, no longer fermented sugars other than glucose and L-arabinose, did not harbor four known virulence-associated genes (iss, tsh, cvaA, papC), and was susceptible to many antimicrobials, with the exception of nalidixic acid. The lethal dose (LD(50) value) of the mutant strain on intravenous challenge in chickens was approximately 10-fold higher than that of the parent strain. Additionally, the mutant strain was rapidly eliminated from chickens, being detected in the respiratory tract only on the first day post-inoculation by fine spray. Administration of the mutant strain via various routes such as spray and eye drop for chickens, as well as in ovo inoculation for embryonated egg, evoked an effective immune response that protected against a virulent wild-type E. coli O78 strain. Specifically, after immunization with the mutant strain, chickens challenged intravenously with an E. coli O78 strain exhibited decreases in mortality, clinical scores, organ lesion scores, and recovery of the challenge strain from organs compared to non-immunized chickens. These findings suggest that AESN1331 is a suitable candidate for a live vaccine strain to protect chickens from colibacillosis caused by avian E. coli O78.


Assuntos
Galinhas/microbiologia , Infecções por Escherichia coli/veterinária , Vacinas contra Escherichia coli/imunologia , Escherichia coli/patogenicidade , Doenças das Aves Domésticas/prevenção & controle , Administração Intravenosa , Animais , Antibacterianos/farmacologia , Antígenos de Bactérias/imunologia , Embrião de Galinha , Galinhas/imunologia , Vermelho Congo , Proteína Receptora de AMP Cíclico/genética , Proteína Receptora de AMP Cíclico/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/prevenção & controle , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Deleção de Genes , Genes Bacterianos , Dose Letal Mediana , Testes de Sensibilidade Microbiana , Ácido Nalidíxico/farmacologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/patologia , Vacinação , Vacinas Atenuadas/imunologia
12.
J Virol Methods ; 299: 114303, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34606795

RESUMO

INTRODUCTION: Plaque assay (PA) is a gold standard for virus titration and neutralization of various cytopathic viruses, including avian nephritis virus (ANV), the etiological agent associated with kidney disorders in chickens. In this study, as an alternative to the labor-intensive PA, we developed a spectrophotometric microplate assay (MA) for ANV titration and neutralization based on the virus cytopathicity to primary chicken kidney (CK) cells. METHODS: CK cells were infected with ANV in the presence or absence of chicken serum in a 96-well microplate, and the virus-induced cytolysis was quantified by measurement of neutral red uptake using a spectrophotometer. The absorbance values obtained were subjected to a sigmoidal four-parameter logistic regression analysis for the virus titer determination and serum neutralization assessment. Accuracy and reliability of the serum neutralization MA in comparison to the standard PA was statistically evaluated. RESULTS: The ANV-MA was capable of quantifying infectious virus titers based on a virus dose-dependent cytolysis of CK cells, and serum neutralization could be assessed as an inhibition of the virus-induced cytolysis accordingly. Statistical evaluation using a 2 × 2 contingency table and receiver-operating characteristic analyses showed 82 % sensitivity, 99 % specificity and 0.97 area under the curve, supporting an overall diagnostic accuracy of the neutralization MA. CONCLUSION: The newly developed MA using simplified experimental procedures in the microplate format and direct spectophotometric data readout is readily applicable to general laboratories for high-throughput screening of serum neutralization of ANV.


Assuntos
Avastrovirus , Animais , Anticorpos Antivirais , Galinhas , Testes de Neutralização/métodos , Reprodutibilidade dos Testes
13.
Vet Microbiol ; 263: 109279, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34798366

RESUMO

The aim of this study was to investigate an isolate of Actinobacillus pleuropneumoniae, named 14-760, which was serologically not classifiable among the recognised serovars of A. pleuropneumoniae. It reacted with the antisera raised against serovars 3, 6, 8, 15 and 17 in the agar gel precipitation (AGP) test, and was positive in the capsular serovar 4-specific PCR (cps4B PCR) assay. The isolate contains a type II capsule locus similar to serovar 4 but with variations in the length of four intergeneric regions (modF-cpxA, cpxD-cpsA, cpsC-a 114 bp orf, and lysA-ydeN), and three gene sequences (modF, cpsC and ydeN). The main difference found between the K4 and K4b cps genes is the additional 35 AAs found in type 4b due to a 4 bp insert in cps4bC. The LPS O-Ag locus is highly similar to that of reference strains of serovars 3, 6, 8, 15, 17 and 19. Isolate 14-760 is biovar 1 and contains solely the structural genes required for toxin ApxII production (apxIICA), and the type I secretion system (apxIBD) for the export of ApxII. Antiserum against isolate 14-760 adsorbed with antigen prepared from serovars 8, 15 or 17 reference strains remained reactive with isolate 14-760, but not with antigens prepared from serovars 1-18. Taken together, our results indicate the existence of a subtype of A. pleuropneumoniae, serovar 4, that we called "K4b:O3″, and we propose isolate 14-760 as the reference strain.


Assuntos
Actinobacillus pleuropneumoniae , Técnicas de Tipagem Bacteriana , Infecções por Actinobacillus/veterinária , Actinobacillus pleuropneumoniae/classificação , Actinobacillus pleuropneumoniae/genética , Animais , Técnicas de Tipagem Bacteriana/veterinária , Genótipo , Pleuropneumonia/microbiologia , Pleuropneumonia/veterinária , Sorogrupo , Sorotipagem/veterinária , Suínos , Doenças dos Suínos/microbiologia
14.
Biochem Biophys Res Commun ; 401(2): 268-74, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20850415

RESUMO

Cycle inhibiting factor (Cif) is one of the effectors delivered into epithelial cells by enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic Escherichia coli (EHEC) via the type III secretion system (TTSS). Cif family proteins, which inhibit host cell-cycle progression via mechanisms not yet precisely understood, are highly conserved among EPEC, EHEC, Yersinia pseudotuberculosis, Photorhabdus luminescens and Burkholderia pseudomallei. Levels of several proteins relevant to cell-cycle progression are modulated by Cullin-RING ligases (CRLs), which in turn are activated by conjugation and deconjugation of NEDD8 to Cullins. Here we show that Cif interacts with NEDD8 and interferes with SCF (Skp1-Cullin1-F-box protein) complex ubiquitin ligase function. We found that neddylated Cullin family proteins accumulated and ubiquitination of p27 decreased in cells infected with EPEC. Consequently, Cif stabilized SCF substrates such as CyclinD1, Cdt1, and p27, and caused G1 cell-cycle arrest. Using time-lapse-imaging of fluorescent ubiquitination-based cell-cycle indicator (Fucci)-expressing cells, we were able to monitor cell-cycle progression during EPEC infection and confirmed the arrest of infected cells at G1. Our in vitro and in vivo data show that Cif-NEDD8 interaction inhibits deneddylation of Cullins, suppresses CRL activity and induces G1 arrest. We thus conclude that the bacterial effector Cif interferes with neddylation-mediated cell-cycle control.


Assuntos
Proteínas Culina/metabolismo , Escherichia coli Enteropatogênica/metabolismo , Infecções por Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas Ligases SKP Culina F-Box/antagonistas & inibidores , Ubiquitinas/metabolismo , Linhagem Celular , Fase G1 , Células HeLa , Humanos , Proteína NEDD8
15.
J Vet Diagn Invest ; 32(4): 581-584, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32517629

RESUMO

Two Actinobacillus pleuropneumoniae isolates from clinical cases of porcine pleuropneumonia in Japan were positive in the capsular serovar 15-specific PCR assay, but nontypeable (NT) in the agar gel precipitation (AGP) test. Nucleotide sequence analysis of gene clusters involved in the biosynthesis of capsular polysaccharide (CPS) and lipopolysaccharide O-polysaccharide (O-PS) revealed that both clusters contained transposable element ISApl1 of A. pleuropneumoniae belonging to the IS30 family. Immunoblot analysis revealed that these 2 isolates could not produce O-PS. We conclude that the ISApl1 of A. pleuropneumoniae can interfere in the biosynthesis of both CPS and O-PS.


Assuntos
Infecções por Actinobacillus/veterinária , Actinobacillus pleuropneumoniae/fisiologia , Elementos de DNA Transponíveis , Pleuropneumonia/veterinária , Polissacarídeos/análise , Doenças dos Suínos/diagnóstico , Infecções por Actinobacillus/diagnóstico , Infecções por Actinobacillus/microbiologia , Actinobacillus pleuropneumoniae/isolamento & purificação , Animais , Genes Bacterianos , Immunoblotting/veterinária , Família Multigênica , Pleuropneumonia/diagnóstico , Pleuropneumonia/microbiologia , Reação em Cadeia da Polimerase/veterinária , Suínos , Doenças dos Suínos/microbiologia
16.
J Vet Diagn Invest ; 21(5): 701-6, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19737769

RESUMO

Quantitative real-time polymerase chain reaction (qPCR) assays were developed and validated in combination with enrichment culture for the detection and discrimination of Erysipelothrix rhusiopathiae and other Erysipelothrix species from tissue samples. The targets for SYBR green qPCR assays were the 16S ribosomal RNA gene for Erysipelothrix species and a gene involved in capsular formation for E. rhusiopathiae. The specificity of the assays was assessed with Erysipelothrix species and other related bacterial species. The limit of detection was found to be 5 colony-forming units per reaction. Amplification of DNA extracted from spleen and joint samples spiked with increasing quantities of Erysipelothrix cells was shown to be equally sensitive to DNA extracted from a pure bacterial culture. The assays were evaluated with 88 tissue samples from 3 experimentally infected pigs and 50 mice and with 36 tissue samples from 3 naturally infected pigs and 11 noninfected pigs. Results were compared with those of direct qPCR and conventional culture. The qPCR after enrichment increased the diagnostic sensitivity over that of culture and qPCR, thereby significantly reducing the total time taken for the detection of E. rhusiopathiae and other Erysipelothrix species. Therefore, this technique could be used for practical applications.


Assuntos
Erysipelothrix/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Animais , DNA Bacteriano/genética , Erysipelothrix/efeitos dos fármacos , Erysipelothrix/genética , Infecções por Erysipelothrix/diagnóstico , Amplificação de Genes , Articulações/microbiologia , Camundongos , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/veterinária , RNA Bacteriano/genética , RNA Bacteriano/isolamento & purificação , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/isolamento & purificação , Valores de Referência , Baço/microbiologia , Suínos , Doenças dos Suínos/microbiologia
17.
J Vet Med Sci ; 81(3): 480-485, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30713216

RESUMO

Six atypical Actinobacillus pleuropneumoniae serovar 15 strains were isolated from pneumonic lesions of naturally infected dead pigs from the same farm in Japan. Genetic analyses of apx genes revealed that the atypical isolates contained the toxin-associated genes apxIBD, apxIIICA, apxIIIBD, and apxIVA, but not apxIICA. Coinciding with the result of the atypical gene profile, analyses of toxin protein production revealed that these atypical isolates expressed only ApxIII but not ApxII. A mouse pathogenicity test showed that the atypical isolate tested seemed to be less virulent than the typical isolates. This is the first report describing the emergence of atypical A. pleuropneumoniae serovar 15, which does not produce ApxII due to the absence of apxIICA genes, in Japan.


Assuntos
Infecções por Actinobacillus/veterinária , Actinobacillus pleuropneumoniae/isolamento & purificação , Proteínas de Bactérias/genética , Genes Bacterianos , Proteínas Hemolisinas/genética , Doenças dos Suínos/microbiologia , Infecções por Actinobacillus/microbiologia , Actinobacillus pleuropneumoniae/genética , Actinobacillus pleuropneumoniae/patogenicidade , Animais , Feminino , Deleção de Genes , Japão , Camundongos , Suínos , Transcriptoma , Virulência/genética
18.
Circ Res ; 98(1): 81-7, 2006 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-16306445

RESUMO

Although microtubules are involved in various pathological conditions of the heart including hypertrophy and congestive heart failure, the mechanical role of microtubules in cardiomyocytes under such conditions is not well understood. In the present study, we measured multiple aspects of the mechanical properties of single cardiomyocytes, including tensile stiffness, transverse (indentation) stiffness, and shear stiffness in both transverse and longitudinal planes using carbon fiber-based systems and compared these parameters under control, microtubule depolymerized (colchicine treated), and microtubule hyperpolymerized (paclitaxel treated) conditions. From all of these measurements, we found that only the stiffness against shear in the longitudinal plane was modulated by the microtubule cytoskeleton. A simulation model of the myocyte in which microtubules serve as compression-resistant elements successfully reproduced the experimental results. In the complex strain field that living myocytes experience in the body, observed changes in shear stiffness may have a significant influence on the diastolic property of the diseased heart.


Assuntos
Microtúbulos/fisiologia , Miócitos Cardíacos/fisiologia , Animais , Cardiomegalia/fisiopatologia , Colchicina/farmacologia , Cricetinae , Citoesqueleto/fisiologia , Feminino , Insuficiência Cardíaca/fisiopatologia , Humanos , Masculino , Mesocricetus , Ratos , Ratos Wistar , Resistência ao Cisalhamento , Estresse Mecânico
19.
J Vet Diagn Invest ; 20(3): 336-42, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18460622

RESUMO

Erysipelothrix rhusiopathiae causes erysipelas in swine and is considered a reemerging disease contributing substantially to economic losses in the swine industry. Since an attenuated live vaccine was commercialized in 1974 in Japan, outbreaks of acute septicemia or subacute urticaria of erysipelas have decreased dramatically. In contrast, a chronic form of erysipelas found during meat inspections in slaughterhouses has been increasing. In this study, a new strain-typing method was developed based on nucleotide sequencing of a hypervariable region in the surface protective antigen (spaA) gene for discrimination of the live vaccine strain from field isolates. Sixteen strains isolated from arthritic lesions found in slaughtered pigs were segregated into 4 major patterns: 1) identical nucleotide sequence with the vaccine strain: 3 isolates; 2) 1 nucleotide substitution (C to A) at position 555: 5 isolates; 3) 1 nucleotide substitution at various positions: 5 isolates; and 4) 2 nucleotide substitutions: 3 isolates. Isolates with the same nucleotide sequence as the vaccine strain were further characterized by other properties, including the mouse pathogenicity test. One strain isolated from pigs on a farm where the live vaccine had been used was found to be closely related to the vaccine strain. The phylogenetic tree constructed based on the spaA sequence suggests that the evolutionary distance of the isolates is related to the pathogenicity in mice. The new strain-typing system based on nucleotide sequencing of the spaA region is useful to discriminate the vaccine strain from field isolates.


Assuntos
Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Vacinas Bacterianas/microbiologia , Regiões Determinantes de Complementaridade/genética , Erysipelothrix/classificação , Análise de Sequência de DNA/veterinária , Animais , Vacinas Bacterianas/imunologia , Sequência de Bases , Erysipelothrix/genética , Filogenia , Análise de Sequência de DNA/métodos , Suínos , Doenças dos Suínos/microbiologia , Doenças dos Suínos/prevenção & controle
20.
Avian Dis ; 52(4): 652-6, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19166058

RESUMO

To detect five different avian Eimeria species, we applied the SYBR Green-based real-time polymerase chain reaction (PCR) assay for the diagnosis of field-isolated parasites by using their individual species-specific primer sets. The primer sets were originally designed for Eimeria acervulina, E brunetti, E necatrix, and E tenella based on the sequence of the internal transcribed spacer 1 region of ribosomal DNA, whereas for E. maxima the primer sets were derived from sequences reported previously. The detection limit of these assays was defined at 10(2) or 10(1) oocysts depending on species. Melting curves from the real-time PCR assay showed that each species has a single peak and specific melting temperature value. Fecal samples from 32 poultry farms, which were endemic for coccidiosis, were examined using this assay. The data showed that E. brunetti was found in 21 farms, E maxima and E. necatrix in 16 farms, E. tenella in 12 farms, and E. acervulina in eight farms. This survey revealed that E brunetti was highly prevalent in Japan. This technique is not only easy and rapid but also available to detect Eimeria species specifically; therefore, it can be a valuable tool for diagnostic work for chicken coccidiosis.


Assuntos
Galinhas , Coccidiose/veterinária , Eimeria/classificação , Doenças das Aves Domésticas/parasitologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Animais , Coccidiose/parasitologia , DNA de Protozoário/classificação , DNA de Protozoário/genética , Eimeria/genética , Feminino , Masculino , Especificidade da Espécie
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