Biology Reference
In-Depth Information
TABLE 8.1
Putative EAEC virulence genes and factors—cont'd
Unique
to EAEC
Factor
Description
Pic
Pic protein has mucinase activity and is capable of
causing hemagglutination of erythrocytes (
Henderson
et al., 1999a
)
No
SepA
Shigella
extracellular protein. May induce mucosal
atrophy and tissue inflammation in
S. flexneri
(
Benjelloun-Touimi et al., 1998
)
No
Sat
Secreted autotransporter toxin. Might induce
cytoskeletal perturbation in intestinal epithelium
accompanied by rearrangement of tight junction
proteins (
Guyer et al., 2000
)
No
EAST-1
Encodes the enteroaggregative heat-stable toxin (EAST-1),
which has physical and mechanistic similarities to
E. coli
STa enterotoxin (
Savarino et al., 1993
)
No
Others
EilA
ND
Salmonella
HilA homolog, activates the bacterial
surface protein Air (
Sheikh et al., 2006
)
Air
Possible aggregation and adherence (
Sheikh et al., 2006
)
ND
Pro. Fl.
Single protein (from strain 042) moiety that has a
sequence similar to that of a flagelin from
Shigella
dysenteriae
(
Steiner et al., 2000
)
No
Irp2
Encodes an iron-uptake system mediated by
siderophore yersiniabactin that plays a role in iron
transport and regulation (
Schubert et al., 1998
)
No
Lectin
A complex carbohydrate that shows cross-reactivity
to the bindings subunit of cholera toxin, and induces
morphological changes in HEp-2 cells and fluid
accumulation in the rabbit ileal loop (
Basu et al., 2004
)
No
a
Unpublished; ND, not determined ; Pro. Fl, proinflamatory flagelins.
set of factors is under the coordinate control of AggR. This hypothesis has not
been rigorously tested.
The natural conditions that result in activation of AggR are unknown. How-
ever, activating conditions for the related RegA, Rns, and ToxT have been
described: Rns (
Grewal et al., 1997
) and ToxT (
Prouty et al., 2005
) regulons are
activated by bile, whereas sodium bicarbonate activates the RegA-dependent
genes (
Hart et al., 2008
).
Once ingested the localization of EAEC in the gastrointestinal tract has not
been well defined. Electron microscopy of infected small intestinal mucosa
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