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Category: Microbial Genetics and Molecular Biology
Genome-Scale Analysis of Virulence Plasmids: the Contribution of Plasmid-Borne Virulence Genes to Enterobacterial Pathogenesis, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555817732/9781555812652_Chap18-1.gif /docserver/preview/fulltext/10.1128/9781555817732/9781555812652_Chap18-2.gifAbstract:
This chapter discusses the genome-scale analysis of virulence plasmids: the contribution of plasmid-borne virulence genes to enterobacterial pathogenesis. The spectrum of diseases caused by Escherichia coli and other enteric bacteria is due to the acquisition of a variety of specific virulence genes harbored on plasmids, on bacteriophages, or within distinct chromosomal DNA segments termed pathogenicity islands (PAIs) that are absent from the genomes of commensal E. coli strains. A study showed that StcE is secreted by the plasmid-encoded type II apparatus, and its expression is regulated by chromosomally encoded Ler, which also controls expression of LEE genes that have key roles in the attaching and effacing phenotype of O157:H7. The chapter emphasizes that virulence plasmids of the enteric bacterial pathogens have evolved by acquiring either individual genes or blocks of genes from bacteriophages and other conjugative plasmids by transposition mechanisms. Many of the remnants of such acquisition events are evident in the sequences of the virulence plasmids of Shigella, the pathogenic E. coli, and Yersinia. Genome sequencing will provide many of the E. coli virulence plasmids, with the advantage of economy of effort and expense, since no separate experiments are needed when the plasmids are present in the genomic DNA preparation at the time of library construction. Collection of sequences that will be made available by the worldwide genome sequencing effort should provide a basis for devising new therapeutic solutions to some of the outstanding problems of infectious diseases, including the further transmission of drug resistance.
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Phylogenetic relationships of Rep proteins from various plasmids. Rep proteins, shown here with their GenBank identifiers, were compared using the ClustalW method by Megalign (DNASTAR). The sequences were aligned using multiple alignment parameters of gap penalty 10 and gap length penalty 10. Proteins mentioned in the text are in bold type.
Phylogenetic relationships of Rep proteins from various plasmids. Rep proteins, shown here with their GenBank identifiers, were compared using the ClustalW method by Megalign (DNASTAR). The sequences were aligned using multiple alignment parameters of gap penalty 10 and gap length penalty 10. Proteins mentioned in the text are in bold type.
Comparison of features of virulence plasmids and related prototypes
Comparison of features of virulence plasmids and related prototypes
Replication, transfer, and maintenance functions
Replication, transfer, and maintenance functions
Sequenced small plasmids from pathogenic Enterobacteriaceae
Sequenced small plasmids from pathogenic Enterobacteriaceae