A small fraction of the molecules internalized by endocytosis reaches the Golgi complex through a retrograde pathway that is poorly understood. In the present work, we used bacterial toxins to study the retrograde pathway in Vero cells. The recombinant B subunit of verotoxin 1B (VT1B) was labeled with fluorescein to monitor its progress within the cell by confocal microscopy. This toxin, which ...

It is important to understand the physicochemical mechanisms that are responsible for the morphological changes in the cell membrane in the presence of various stimuli such as osmotic pressure. Lipid rafts are believed to play a crucial role in various cellular processes. It is well established that Ctb (Cholera toxin B subunit) recognizes and binds to GM1 (monosialotetrahexosylganglioside) on ...

The subunit B of cholera toxin (CTB), which specifically binds with ganglioside GM1 enriched in membrane lipid rafts, is known to interfere with multiple cell functions. However, the specific, stable and spatially defined membrane signaling induced by CTB binding is often difficult to investigate by applying CTB molecules in bulk solution due to quick internalization, elicited intracellular rea...

INTRODUCTION Cholera toxin B subunit (CTB) is a component of an internationally licensed oral cholera vaccine. The protein induces neutralizing antibodies against the holotoxin, the virulence factor responsible for severe diarrhea. A field clinical trial has suggested that the addition of CTB to killed whole-cell bacteria provides superior short-term protection to whole-cell-only vaccines; howe...

Traditional studies of neuroanatomical connections require injection of tracer compounds into living brains, then histology of the postmortem tissue. Here, we describe and validate a compound that reveals neuronal connections in vivo, using MRI. The classic anatomical tracer CTB (cholera-toxin subunit-B) was conjugated with a gadolinium-chelate to form GdDOTA-CTB. GdDOTA-CTB was injected into t...

Diarrheal diseases caused by Vibrio cholerae and enterotoxigenic E. coli (ETEC) lead to millions of deaths each year. The protein toxins produced by these bacteria are 80% identical and comprise a single toxic A-subunit associated with a pentamer of B-subunits. The B-pentamer enables the toxin to enter cells by first binding to the ganglioside GM1 glycolipid 1 (Figure 1a,b). Inhibitors of this ...

A mixed phospholipid-cholestrol bilayer, with cholera toxin B (CTB) units attached to the monosialotetrahexosylganglioside (GM1) binding sites in the distal leaflet, was deposited on a Au(111) electrode surface. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) measurements were used to characterize structural and orientational changes in this model biological membr...

BACKGROUND Infection with Vibrio cholerae induces durable immunity against subsequent disease, a process hypothesized to reflect anamnestic immune responses at the intestinal mucosa. The presence of antigen-specific memory B cells may therefore be a more direct measure of protection than serum antibody responses. METHODS We measured immunoglobulin (Ig) G memory B cells specific to cholera tox...

Corn, one of the most important forage crops worldwide, has proven to be a useful expression vehicle due to the availability of established transformation procedures for this well-studied plant. The exotoxin Apx, a major virulence factor, is recognized as a common antigen of Actinobacillus (A.) pleuropneumoniae, the causative agent of porcine pleuropneumonia. In this study, a cholera toxin B (C...

We have constructed an overexpression system in which the gene encoding the B subunit of cholera toxin (CTB) was placed under the control of the strong tacP promoter in a wide host range plasmid. Recombinant nontoxigenic classical and E1 Tor Vibrio cholerae strains of different serotypes harboring this plasmid excreted 10- to 100-fold higher amounts of CTB than any other wild-type or recombinan...