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Master's Dissertation
DOI
10.11606/D.42.2012.tde-20092012-095345
Document
Author
Full name
Natalia Cristina de Freitas
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2012
Supervisor
Committee
Piazza, Roxane Maria Fontes (President)
Amaral, Tania Aparecida Tardelli Gomes do
Ferreira, Rita de Cassia Cafe
Title in Portuguese
Fímbrias Pil em Escherichia coli enteropatogênica atípica: Caracterização e investigação do papel de PilS e PilV na adesão bacteriana.
Keywords in Portuguese
Escherichia coli
Adesão bacteriana
Bactérias gram-negativas
Diarreia
fatores de virulência
Fimbria pil
Fimbrias do tipo IV
Virulência
Abstract in Portuguese
Fímbrias do tipo IV estão associadas a diversos fenótipos em bactérias gram-negativas, e o presente estudo consistiu na caracterização da fímbria Pil e investigação de seu papel na adesão bacteriana de isolados de EPEC atípica. Por PCR e RT-PCR foram investigadas a presença e a funcionalidade do operon Pil e os resultados demonstraram que este está sendo transcrito somente nos isolados BA558 e BA956. Os genes pilS e pilV foram clonados em vetor de expressão para obtenção das proteínas Pil recombinantes e produção de anticorpos policlonais. A análise qualitativa dos testes de inibição da adesão utilizando os soros anti-PilS e anti-PilV juntos demonstraram que o isolado BA558 apresentou mudança de fenótipo de adesão. Esses resultados nos permitem concluir que o operon Pil está funcional em BA558 e BA956, e a expressão da fímbria Pil nessas cepas não está relacionada à formação de biofilme e autoagregação, porém a proteína fimbrial PilS juntamente com a adesina PilV parecem exercer uma função acessória importante na interação de BA558 às células HEp-2.
Title in English
Type IV pilus in atypical enteropathogenic Escherichia coli: characterization and investigation of PilS and PilV in bacterial adhesion role.
Keywords in English
Escherichia coli.
Diarrhea
Fimbriae propyl
Gram-negative bacterial adhesion
Type IV fimbriae
Virulence
Virulence factors
Abstract in English
Type IV fimbriae are associated with several phenotypes in gram-negative bacteria. The aim of this study was the characterization of the Pil fimbria and its role in the interaction of atypical EPEC isolates in bacterial adhesion. Using PCR and RT-PCR, we investigated the presence and functionality of the pil operon genes. The results showed that these genes are transcribed only in the BA558 and BA956 isolates. The pilS and pilV genes were cloned into an expression vector for recombinant proteins and polyclonal antibodies production. Qualitative analysis of the adherence inhibition assays using both rabbit sera changed to localized-like the phenotype of BA558 isolate adhesion. Together, these results allow us to conclude that the Pil operon is functional only in the BA558 and BA956 isolates and that the expression of Pil fimbriae in aEPEC is not related to biofilm formation and autoaggregation but, the fimbrial PilS protein together with PilV adhesin seem to play an important accessory function in the interaction between the BA558 and epithelial cells in vitro.
 
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Publishing Date
2012-10-25
 
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