Influence of the major nitrite transporter NirC on the virulence of a Swollen Head Syndrome Avian Pathogenic E. coli (APEC) strain

Paiva, Jacqueline Boldrin de; Leite, Jáder Ferreira; Silva, Livia Pilatti Mendes da; Rojas, Thaís Cabrera Galvão; Pace, Fernanda de; Conceição, Rogério Arcuri; Sperandio, Vanessa; Silveira, Wanderley Dias da

doi:10.1016/j.vetmic.2014.11.015

Cited by 20 publications

(25 citation statements)

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“…Primers for quantitative RT-PCR (qRT-PCR) were constructed with Primer Express software version 3.0 (Applied Biosystems) (see Table S1 in the supplemental material), using the SCI-07 genome as the template. The qRT-PCR experiments were performed as described previously (15). RNA polymerase subunit A (rpoA) was used as the endogenous control (see Table S1).…”

Section: Methodsmentioning

confidence: 99%

“…The ⌬yadC strain was constructed following the methodology described by Datsenko and Wanner (17). To replace gene yadC by homologous recombination, a chloramphenicol (Cm) cassette from pKD3 was amplified, and strain SCI-07, harboring the red plasmid pKD46, was transformed by electroporation as described by de Paiva et al (15). The ⌬yadC deletion was confirmed by PCR using primers F-yadC 1, R-yadC 2 (internal), F-yadC 3, and R-yadC 4 (external) (see Table S1 in the supplemental material).…”

Section: Methodsmentioning

confidence: 99%

“…The fragment was then ligated to plasmid pACYC177 DraIII and HindIII restriction sites. The recombinant plasmid was electroporated into competent cells of strain DH10␤ (15). Positive colonies were tested for the presence of yadC by PCR using the same complementation primers.…”

Section: Methodsmentioning

confidence: 99%

“…Cultures from the SCI-07, ⌬yadC, and C.⌬yadC strains were grown (LB medium) at 37°C for 24 h. Briefly, groups of 20 birds for each strain were inoculated in the right thoracic air sac with 0.1 ml of a suspension containing 10 9 CFU or with 0.1 ml of PBS as negative control (15). Birds were observed every 12 h up to 7 days after inoculation, and the numbers of deaths were recorded as described by Antão et al (20).…”

Section: Methodsmentioning

confidence: 99%

“…At 24 and 48 hpi, chickens were euthanized. Afterwards, samples of the lung, liver, and heart were homogenized, and colony forming unit determination was performed as described previously (15).…”

Section: Methodsmentioning

confidence: 99%

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Fimbria-Encoding Gene yadC Has a Pleiotropic Effect on Several Biological Characteristics and Plays a Role in Avian Pathogenic Escherichia coli Pathogenicity

et al. 2016

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bThe extraintestinal pathogen termed avian pathogenic Escherichia coli (APEC) is known to cause colibacillosis in chickens. The molecular basis of APEC pathogenesis is not fully elucidated yet. In this work, we deleted a component of the Yad gene cluster (yadC) in order to understand the role of Yad in the pathogenicity of the APEC strain SCI-07. In vitro, the transcription level of yadC was upregulated at 41°C and downregulated at 22°C. The yadC expression in vivo was more pronounced in lungs than in spleen, suggesting a role in the early steps of the infection. Chicks infected with the wild-type and mutant strains presented, respectively, 80% and 50% mortality rates. The ⌬yadC strain presented a slightly decreased ability to adhere to HeLa cells with or without the D-mannose analog compared with the wild type. Real-time PCR (RT-PCR) assays showed that fimH was downregulated (P < 0.05) and csgA and ecpA were slightly upregulated in the mutant strain, showing that yadC modulates expression of other fimbriae. Bacterial internalization studies showed that the ⌬yadC strain had a lower number of intracellular bacteria recovered from Hep-2 cells and HD11 cells than the wild-type strain (P < 0.05). Motility assays in soft agar demonstrated that the ⌬yadC strain was less motile than the wild type (P < 0.01). Curiously, flagellum-associated genes were not dramatically downregulated in the ⌬yadC strain. Taken together, the results show that the fimbrial adhesin Yad contributes to the pathogenicity and modulates different biological characteristics of the APEC strain SCI-07. Avian pathogenic Escherichia coli (APEC) strains cause a variety of extraintestinal infections in poultry collectively known as colibacillosis (1, 2). Although the complete mechanisms of APEC pathogenicity are not fully elucidated, it is believed that colibacillosis starts with colonization of the host's upper respiratory tract, with the bacterium expressing one or more colonization factors known as adhesins (3). The infection can subsequently spread into the lungs and other inner organs, leading to a fatal septicemia (1,4,5). Among the known APEC adhesins, those more studied are the type 1 fimbriae, P fimbriae, and curli fimbriae, respectively (6).Besides their roles in the adhesion and subsequent colonization of environmental surfaces, those fimbriae are assumed to be essential for the establishment of a host-parasite relationship and further disease progression (7). Both type 1 and curli fimbriae play important roles in the initial bacterial colonization of the respiratory epithelium (1, 8), while P fimbriae (9) are important for later stages of infection (1).In addition to the fimbriae mentioned above, E. coli possesses several other fimbrial operons (i.e., Yad, Ycb, Ybg, Yfc, Yra, Sfm, Ygi, and Yeh) that display sequence and organizational homologies to type 1 fimbria and could contribute to E. coli's ability to adhere to and colonize the host epithelia (10, 11).The adhesion operon Yad is composed of seven genes, yadN (major subunit), ecpD (usher...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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