| Autor: |
Burgos, Ylanna Kelner, Pries, Karin, Pestana de Castro, Antonio Fernando, Beutin, Lothar |
| Předmět: |
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| Zdroj: |
FEMS Microbiology Letters; Mar2009, Vol. 292 Issue 2, p194-202, 9p, 6 Black and White Photographs, 1 Diagram, 2 Charts |
| Abstrakt: |
The 157-kb conjugative plasmid pEO5 encoding α-haemolysin in strains of human enteropathogenic Escherichia coli (EPEC) O26 was investigated for its relationship with EHEC-haemolysin-encoding plasmids of enterohaemorrhagic E. coli (EHEC) O26 and O157 strains. Plasmid pEO5 was found to be compatible with EHEC-virulence plasmids and did not hybridize in Southern blots with plasmid pO157 from the EHEC O157:H7 strain EDL933, indicating that both plasmids were unrelated. A 9227-bp stretch of pEO5 DNA encompassing the entire α- hlyCABD operon was sequenced and compared for similarity to plasmid and chromosomally inherited α- hly determinants. The α- hly determinant of pEO5 (7252 bp) and its upstream region was most similar to corresponding sequences of the murine E. coliα-hly plasmid pHly152, in particular, the structural α- hlyCABD genes (99.2% identity) and the regulatory hlyR regions (98.8% identity). pEO5 and α-hly plasmids of EPEC O26 strains from humans and cattle were very similar for the regions encompassing the structural α- hlyCABD genes. The major difference found between the hly regions of pHly152 and pEO5 is caused by the insertion of an IS 2 element upstream of the hlyC gene in pHly152. The presence of transposon-like structures at both ends of the α- hly sequence indicates that this pEO5 virulence factor was probably acquired by horizontal gene transfer. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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