Caracterização da proteína Pic (protein involved in colonization) em Escherichia coli enteropatogênica atípica.

Abreu Junior, Afonso Gomes

doi:10.11606/T.42.2015.tde-10062015-160611

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DOI

https://doi.org/10.11606/T.42.2015.tde-10062015-160611

Document

Doctoral Thesis

Author

Abreu Junior, Afonso Gomes (Catálogo USP)

Full name

Afonso Gomes Abreu Junior

Institute/School/College

Instituto de Ciências Biomédicas

Knowledge Area

Microbiology

Date of Defense

2015-03-13

Published

São Paulo, 2015

Supervisor

Elias Junior, Waldir Pereira (Catálogo USP)

Committee

Elias Junior, Waldir Pereira (President)
Amaral, Tania Aparecida Tardelli Gomes do
Huenuman, Nilton Erbet Lincopan
Neves, Carla Taddei de Castro
Silva, Rosa Maria

Title in Portuguese

Caracterização da proteína Pic (protein involved in colonization) em Escherichia coli enteropatogênica atípica.

Keywords in Portuguese

Escherichia coli enteropatogênica atípica
Atividade mucinolítica
Colonização
Hemaglutinação
Pic
Sistema complemento

Abstract in Portuguese

A serinoprotease Pic é uma proteína autotransportadora que apresenta papel importante na colonização da mucosa intestinal por E. coli enteroagregativa (EAEC). Uma cepa de E. coli enteropatogênica atípicas (aEPEC) albergando o gene pic foi detectada em um estudo prévio. O presente estudo teve como objetivo caracterizar a proteína Pic produzida por essa cepa de aEPEC (BA589). O gene pic em BA589 está presente em um plasmídeo de alto peso molecular (~98 kb) e o sequenciamento desse gene mostrou identidade de 99% com pic de EAEC 042. Pic da cepa BA589 (Pic₅₈₉) foi capaz de clivar mucina bovina, hemaglutinar eritrócitos de coelho e clivar moléculas das três vias sistema complemento. O mutante BA589Dpic todas essas atividades in vitro. A cepa selvagem foi capaz de colonizar o intestino de camundongos tratados com estreptomicina, o que não foi observado com o mutante BA589Dpic. Desta forma, a serinoprotease Pic representa um fator de virulência adicional na cepa de aEPEC BA589, relacionada às etapas de adesão, colonização e evasão do sistema imune inato.

Title in English

Characterization of Pic (protein involved in colonization) in atypical enteropathogenic Escherichia coli.

Keywords in English

Atypical enteropathogenic Escherichia coli
Colonization
Complement system
Hemagglutination
Mucinolytic activity
Pic

Abstract in English

The serine protease Pic is an autotransporter protein that plays an important role in the colonization of the intestinal mucosa by enteroaggregative E. coli (EAEC). An atypical enteropathogenic E. coli (aEPEC) strain harboring the pic gene has been detected in a previous study. The present study aimed to characterize the protein Pic produced by that aEPEC strain (BA589). In BA589 pic is located in a high molecular weight plasmid (~98 kb), and sequencing of this gene showed 99% identity with pic from EAEC 042. Pic from BA589 (Pic₅₈₉) was able to cleave bovine mucin, hemagglutinate rabbit erythrocytes and cleave molecules of the three complement system pathways. The mutant BA589Dpic lost all these capacities. The wild type strain was able to colonize the intestine of streptomycin treated mice, which was not observed with the mutant BA589Dpic. Thus, the serine protease Pic represents an additional virulence factor in aEPEC strain BA589, associated with adherence, colonization and evasion of innate immune system.

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Publishing Date

2015-06-11

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