Enteroaggregative Escherichia coli (EAEC) has been implicated as an agent of pediatric diarrhea in the developing world. We have shown previously that EAEC adheres to HEp-2 cells by virtue a plasmid-encoded fimbrial adhesin designated aggregative adherence fimbria I (AAF/I), genes for which cloned and sequenced. However, not all strains express AAF/I. Using TnphoA mutagenesis, we characterized novel (designated AAF/II) mediates human-pathogenic strain 042. AAF/II is 5 nm diameter does bind...

ABSTRACT Enteroaggregative Escherichia coli (EAEC) is an emerging cause of diarrheal illness. Clinical data suggest that diarrhea caused by EAEC predominantly secretory in nature, but the responsible enterotoxin has not been described. Work from our laboratories implicated a ca. 108-kDa protein as heat-labile and cytotoxin, evidenced rises short-circuit current falls tissue resistance rat jejunal mounted Ussing chamber. Here we report genetic cloning, sequencing, characterization this...

ABSTRACT The phylogenetics of the various pathotypes diarrheagenic Escherichia coli are not completely understood. In this study, we identified several plasmid and chromosomal genes in pathogenic enteroaggregative E. (EAEC) prototype strain 042 determined prevalence these loci among EAEC diffusely adherent strains. distribution is analyzed within an evolutionary framework provided by characterization allelic variation housekeeping via multilocus enzyme electrophoresis. Our data reveal that...

The plasmid-encoded toxin (Pet) of enteroaggregative Escherichia coli (EAEC) belongs to a family high-molecular-weight serine protease autotransporters Enterobacteriaceae (SPATEs) which also includes Pic from EAEC and Shigella flexneri, EspC enteropathogenic E. coli, EspP enterohemorrhagic Sat uropathogenic Tsh avian pathogenic SepA S. flexneri. Phylogenetic analysis shows the SPATE proteins represent distinct subfamily with amino acid identities ranging 35 55%, providing powerful resource...

ABSTRACT At least five proteins are secreted extracellularly by enteropathogenic Escherichia coli (EPEC), a leading cause of infant diarrhea in developing countries. However only one, EspC, is known to be independently the type III secretion apparatus encoded genes located within 35.6-kb locus enterocyte effacement pathogenicity island. EspC member autotransporter family proteins, and portion molecule 110 kDa. Here we determine that espC gene second EPEC island at 60 min on chromosome E. ....

ABSTRACT A hallmark of enteroaggregative Escherichia coli (EAEC) infection is a formation biofilm, which comprises mucus layer with immersed bacteria in the intestines patients. While studying mucinolytic activity Pic an vivo system, rat ileal loops, we surprisingly found that EAEC induced hypersecretion mucus, was accompanied by increase number mucus-containing goblet cells. Interestingly, isogenic pic mutant (EAEC Δ ) unable to cause this hypersecretion. Furthermore, purified also able...

ABSTRACT We have previously described enteroaggregative Escherichia coli (EAEC) strains that induce cytotoxic effects on T84 cells, ligated rat ileal loops, and human intestine in culture. Such secrete a 104-kDa protein termed Pet (for plasmid-encoded toxin). also shown the toxin induces rises short-circuit current decreases electrical resistance jejunum mounted an Ussing chamber. The nucleotide sequence of pet gene revealed is member autotransporter class secreted proteins. Here we show...

ABSTRACT Many pathogenic bacteria subvert normal host cell processes by delivering effector proteins which mimic eukaryotic functions directly into target cells. EspF is a multifunctional protein injected cells attaching and effacing pathogens, but its mechanism of action not understood completely. In silico analyses revealed two key motifs: proline-rich domains PDZ domain binding motifs. Such functional may allow to act as an actin nucleation-promoting factor mimicking proteins. agreement...

Cholera toxin (CT) is an AB(5) that moves from the cell surface to endoplasmic reticulum (ER) by retrograde vesicular transport. In ER, catalytic A1 subunit dissociates rest of and enters cytosol exploiting quality control system ER-associated degradation (ERAD). The driving force for CTA1 dislocation into unknown. Here, we demonstrate cytosolic chaperone Hsp90 required passage cytosol. bound in ATP-dependent manner was blocked geldanamycin (GA), established inhibitor. CT activity against...

ABSTRACT Enteroaggregative Escherichia coli (EAEC) strains have been shown to adhere human intestinal tissue in an vitro organ culture (IVOC) model, and certain manifest mucosal toxicity. We recently described the EAEC plasmid-encoded toxin (Pet), a member of specific serine protease subclass autotransporter proteins. When injected into rat ileal loops, Pet both elicited fluid accumulation had cytotoxic effects on mucosa. Furthermore, protein caused rises short circuit current from jejunal...

ABSTRACT The pathogenic mechanisms of enteroaggregative Escherichia coli (EAggEC) infection are not fully elucidated. In this work we show that an ammonium sulfate precipitate culture supernatant EAggEC strain 049766 increased the potential difference (PD) and short-circuit current (Isc) in rat jejunal preparations mounted Ussing chambers. contained two major proteins 108 116 kDa, which were partially copurified by chromatography DEAE-cellulose. This chromatographic fraction (peak I) PD Isc...

EspC (Escherichia coli secreted protein C) of enteropathogenic E. (EPEC) shows the three classical domains autotransporter proteins and has a conserved serine protease motif belonging to SPATE (serine autotransporters Enterobacteriaceae) subfamily. its homolog Pet in enteroaggregative (EAEC) bear same sequence within motif, both produce enterotoxic effects, suggesting that like Pet, could be internalized reach cleave calmodulin-binding domain fodrin, causing actin cytoskeleton disruption....

Background We have previously shown that the enterotoxin SigA which resides on she pathogenicity island (PAI) of S. flexneri 2a is an autonomously secreted serine protease capable degrading casein. also demonstrated cytopathic for HEp-2 cells and plays a role in intestinal fluid accumulation associated with infections. Methods/Principal Findings In this work we show binds specifically to degrades recombinant human αII spectrin (α-fodrin) vitro, suggesting cytotoxic enterotoxic effects...

Enteroaggregative and uropathogenic Escherichia coli, Shigella flexneri 2a, the hybrid enteroaggregative/Shiga toxin-producing E. coli strain (O104:H4) are important pathogens responsible for intestinal urinary tract infections, as well sepsis hemolytic uremic syndrome. They have in common production of a serine protease called Pic. Several biological roles Pic been described, including protection DH5α from complement-mediated killing. Hereby we showed that significantly reduces complement...

Although Entamoeba dispar displays a similar morphology to histolytica, cellular and molecular studies have revealed significant differences between these two amoebae, including the former being characterized as non-pathogenic later pathogenic. However, recent in vivo vitro experiments shown that E. strains of different origin are capable causing liver damage destroying cell culture lines presence common intestinal bacteria. These results suggested may present pathogenic behavior according...

Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder caused by the expression of progerin, mutant variant Lamin A. Recently, HGPS studies have gained relevance because unraveling its underlying mechanism would help to understand physiological aging. We previously reported that CRM1-mediated nuclear protein export pathway exacerbated in cells, provoking mislocalization numerous targets CRM1. showed normalization this pharmacologically inhibiting CRM1 with LMB...