Rab family guanosine triphosphatases (GTPases) together with their regulators define specific pathways of membrane traffic within eukaryotic cells. In this study, we have investigated which Rab GTPase-activating proteins (GAPs) can interfere with the trafficking of Shiga toxin from the cell surface to the Golgi apparatus and studied transport of the epidermal growth factor (EGF) from the cell s...

Enterohemorrhagic Escherichia coli (EHEC) causes hemorrhagic colitis in humans and, in a subgroup of infected subjects, a more serious condition called hemolytic-uremic syndrome (HUS). These conditions arise because EHEC produces two antigenically distinct forms of Shiga toxin (Stx), called Stx1 and Stx2. Despite this, the production of Stx2 by virtually all EHEC serotypes and the documented ro...

Shiga toxin-producing Escherichia coli have been associated with food-borne illnesses. Pasteurization is used to inhibit microbial growth in milk, and an open question is whether milk pasteurization inactivates Shiga toxins. To answer this question we measured Shiga toxin's inhibition effect on Vero cell dehydrogenase activity and protein synthesis. Our data demonstrate that Shiga toxin 2 (Stx2...

Shiga toxin-producing Escherichia coli causes bloody diarrhea and hemolytic-uremic syndrome and serious outbreaks worldwide. Here, we report the draft genome sequence of E. coli NCCP15657 isolated from a patient. The genome has virulence genes, many in the locus of enterocyte effacement (LEE) island, encoding a metalloprotease, the Shiga toxin, and constituents of type III secretion.

In this report, we present a PCR protocol for rapid identification of enterohemorrhagic Escherichia coli on a LightCycler instrument. In a multiplex assay, the genes encoding Shiga toxin 1 and Shiga toxin 2 are detected in a single reaction capillary. A complete analysis of up to 32 samples takes about 45 min.

Fecal samples (n = 531) submitted to a regional clinical laboratory during a 6-month period were tested for the presence of Shiga toxin using both a Vero cell cytotoxicity assay and the Shiga Toxin Quik Chek test (STQC), a rapid membrane immunoassay. Testing the samples directly (without culture), 9 positives were identified by the Vero cell assay, all of which were also detected by the STQC. T...

Cholera and Shiga toxin bind to the cell surface via glycolipid receptors GM1 and Gb3, respectively. Surprisingly, the majority of Vero cells from a non-synchronized population bind either Cholera or Shiga toxin but not both toxins. The hypothesis that the differential expression of toxin receptors is regulated by the cell cycle was tested. We find that Cholera toxin binds preferentially in G0/...

IS1203v is an insertion sequence which has been found in inactivated Shiga toxin 2 genes of Escherichia coli O157:H7. We analyzed the transpositional mechanism of IS1203v in order to investigate whether the Shiga toxin 2 genes inactivated by IS1203v could revert to the wild type. When the transposase activity of IS1203v was enhanced by artificial frameshifting, IS1203v was obviously excised fro...