1. Examples of PAI of various pathogens.
Examples of PAI of various pathogens. The topology of PAI of various pathogens is depicted to demonstrate different features of PAI. The functional classes of the genes are as indicated in the figure. (A) The cag island of H. pylori harbors genes for a type IV secretion system (T4SS) (grey symbols) that can mediate the translocation of the effector protein CagA (dark grey) into eukaryotic cells modified from reference 92. (B) Salmonella SPI-2 has a mosaic structure. It has been defined as a genetic element of about 40 kb that is absent from the related species E. coli. Only a 25-kb portion is required for systemic infection and encodes a T3SS system (grey), secreted proteins (dark grey), and regulatory proteins (white). Another portion (15 kb) is not required for virulence and harbors genes for metabolic or unknown functions (light grey symbols), such as an enzyme system for alternative electron acceptors during anaerobic growth. Genes associated with mobility are indicated by dark dotted symbols. Modified from reference 134. (C) The HPI of Y. enterocolitica is an example of an unstable PAI. Several is elements are present within this PAI (dotted arrows). Genes in HPI encode an high-affinity iron uptake system (dark grey) that is important for the extracellular proliferation of the pathogen during colonization of the host. Modified from reference 45. (D) The νSal PAI of MRSA is shown. A remarkable feature of PAI in S. aureus is the presence of a large number of genes with related functions, such as genes for enterotoxin (dark grey) or lipoproteins (grey). Modified from reference 9.
Herbert Schmidt, and Michael Hensel Clin. Microbiol. Rev. 2004; doi: /CMR