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Doctoral Thesis
DOI
10.11606/T.87.2014.tde-08122014-103936
Document
Author
Full name
Francielli Mahnic de Vasconcellos
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2014
Supervisor
Committee
Elias Junior, Waldir Pereira (President)
Amaral, Tania Aparecida Tardelli Gomes do
Neves, Carla Taddei de Castro
Rivera, Irma Nelly Gutierrez
Sircili, Marcelo Palma
Title in Portuguese
Estudo do padrão de adesão agregativa de Escherichia coli do sorotipo O142:H34.
Keywords in Portuguese
Escherichia coli enteropatogênica
Adesão
Fímbria AAF/I
Fímbria ECP
Abstract in Portuguese
Um estudo prévio descreveu uma cepa de Escherichia coli enteropatogênica (EPEC) do sorotipo O142:H34 (Ec48/66) que apresentava o padrão de adesão agregativa (AA), característico de E. coli enteroagregativa (EAEC), e os genes eae e aatA. O objetivo deste estudo foi avaliar o papel de fímbrias no padrão AA dessa cepa. A mesma aderiu no padrão AA nas linhagens HeLa, HEp-2, HT-29 e T84, além de causar a lesão A/E em células HeLa e HT-29. Foi detectada a presença dos genes que compõem o operon da fímbria AAF/I de EAEC e da fímbria E. coli common pilus (ECP). Ambos os operons foram sequenciados mostrando alta identidade com os operons presentes em EAEC (agg) e EPEC (ecp). Mutantes nos genes aggC e ecpC mantiveram o padrão AA e a capacidade de causar a lesão A/E em células HeLa. O mutante em aggC apresentou diminuição significativa da adesão. Análises filogenéticas posicionaram essa cepa em um grupo constituído por EPEC. A cepa Ec48/66 é uma EPEC atípica que expressa o padrão AA, o qual é parcialmente dependente de uma variante de AAF/I, mas não de ECP.
Title in English
Study of aggreggative adherence pattern of Escherichia coli from serotype O142:H34.
Keywords in English
AAF/I fimbriae
Adhesion
ECP fimbriae
Enterophatogenic Escherichia coli
Abstract in English
A previous study described a strain of enteropathogenic Escherichia coli (EPEC), serotype O142:H34 (Ec48/66), presenting the aggregative adherence pattern (AA), typical of enteroaggregative E. coli (EAEC), and the eae and aatA genes. The aim of this study was to evaluate the role of fimbriae in the AA pattern of Ec48/66. This strain presented the AA pattern in HeLa, HEp-2, HT-29 and T84 cells, and the ability to cause the A/E lesion in HeLa and HT-29 cells. The presence of the genes comprising the operons of AAF/I fimbriae and E. coli common pilus (ECP) was detected. Both operons were sequenced showing high identity with the operons present in EAEC (agg) and EPEC (ecp). Mutants in the aggC and ecp genes maintained the AA pattern and the ability to cause the A/E lesion in HeLa cells. The aggC mutation significantly reduced the adherence. Phylogenetic analyzes located the strain in the group consisting of EPEC. The Ec48/66 strain is an atypical EPEC expressing the AA pattern, which is partially dependent on a variant of AAF/I, but not on ECP.
 
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Release Date
2016-12-09
Publishing Date
2014-12-10
 
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