Toxins cholera

A failure to turn off GTP-activated Ga has dire consequences. For example, in the disease cholera, cholera toxin produced by the bacterium Vibrio cholerae binds to Ga and prevents GTP hydrolysis, resulting in the continued excretion of sodium and water into the gut. 

Cation-exchangers 150, 165 Cell organelles 144 Cellulose 137 Cholera toxin 169... 

Protein toxins acting intracellularly are often composed of two subunits (A/B model). One subunit is catalytic (A-subunit) and the other is responsible for binding and cell entry (B-subunit). Following binding to an extracellular membrane receptor, the toxins are endocytosed. From the endosomes, the A-subunit is directly (pH dqDendent) transferred into the cytosol (e.g., diphtheria toxin and anthrax toxin) or the toxin is transported in a retrograde manner via the golgi to the ER (e.g., cholera toxin), where translocation into the cytosol occurs [1]. 

Cholera toxin, heat labile coli toxins Gs proteins ADP-ribosylation Activation of adenylate cyclase (cholera, traveler -d iarrhea)... 

Cholera toxin is a protein toxin of Vibrio choleme. Toxin ADP-ribosylates the a-subunit of the Gs heterotrimeric... 

Cholera toxin-induced diarrhoea 2. Increased AEA levels after administration of cholera toxin to mice, a model of diarrhoea, exert anti-secretory action in the small intestine 2. Inhibitors of cellular reuptake... 

Liu S, Kiick KL (2008) Architecture effects on the binding of cholera toxin by helical glycopolypeptides. Macromolecules 41 764—772... 

Figure 14-13. G i ganglioside, a monosialoganglio-side, the receptor in human intestine for cholera toxin.

Glycosphingolipids are constituents of the outer leaflet of plasma membranes and are important in cell adhesion and cell recognition. Some are antigens, eg, ABO blood group substances. Certain gangliosides function as receptors for bacterial toxins (eg, for cholera toxin, which subsequently activates adenylyl cyclase). 

Bacterial toxins Heat-labile enterotoxin of Ecoli and cholera toxin... 

Cholera toxin and related toxins act as immune modulators, with potential use as adjuvants and as therapeutic agents in the treatment of immunologically mediated human disease. 

Gs — activates adenylyl cyclase (irreversibly activated by cholera toxin)... 

Opiates and various derivatives are commonly used to treat diarrhea, partly because they inhibit electrolyte secretion (Suzuki et al., 2000 Tumberg, 1983). Other phytochemicals counter the secretory responses to cholera toxin (Oi et al., 2002). An example would be the decreased chloride secretion caused by proanthocyanide and the ability to inhibit the secretory diarrhea caused by cholera toxin, but only if administered first (Hor et al., 1995). In the light of the co-transport of water and electrolytes by carriers of glucose... 

H, MATSUURA D, MIYAKE M, UENO M, TAKAI I, YAMAMOTO T, KUBO M, MOSS J, NODA M (2002) Identification in traditional herbal medications and confirmation by synthesis of factors that inhibit cholera toxin-induced fluid accumulation. Proc Natl Acad Sci U S A. 99 3042-6. 

Fig. 12. Tentative model of the signal transduction chain that links the perception of pectic fragments to defense responses in carrot cells. Abbreviations apy, heterotrimeric G protein CaM, calmodulin 4CL, 4-coumarate-CoA ligase CTX, cholera toxin FC, fusicoccine GDP-P-S and GTP-y-S, guanosine 5 -0-(2-thiodiphosphate) and guanosine 5 -0-(3-thiotriphosphate) IP3, 1,4,5-inositol trisphosphate PAL, phenylalanine ammonia-lyase PLC, phospholipase C PR, pathogenesis related PTX, pertussis toxin Rc, receptor SP, staurosporine. Activation and inhibition are symbolized by + and -respectively.

Stable analogs of GTP and GDP can be used to study the role of the G-protein, as indicated above. Thus, stable GTP analogs enhance agonist-induced receptor-mediated effects and slow their reversal, as shown in Figure 7.6. Pertussis and cholera toxins can also be used to inhibit or activate certain G-proteins, as indicated. 

Luppi, P. H., Sakai, K., Fort, P., Salvert, D. Jouvet, M. (1988). The nuclei of origin of monoaminergic, peptidergic, and cholinergic afferents to the cat nucleus reticularis magnocellularis a double-labeling study with cholera toxin as a retrograde tracer. J. Comp. Neurol. 277, 1-20. 

Luppi P. H Aston-Jones G Akaoka H., Chouvet G., Jouvet M. (1995). Afferent projections to the rat locus coeruleus demonstrated by retrograde and anterograde tracing with cholera-toxin B subunit and Phaseolus vulgaris leucoagglutinin. Neuroscience 65(1), 119-60. 

Behzadi, G., Kalen, P., Parvopassu, R Wiklund, L. (1990). Afferents to the median raphe nucleus of the rat retrograde cholera toxin and wheat germ conjugated horseradish peroxidase tracing, and selective D-[3H]aspartate labelling of possible excitatory amino acid inputs. Neuroscience 37, 77-100. 

Wilson, A.D., Bland, P.W. and Stokes, C.R. (1990) Expression and distribution of la antigen in the murine small intesine influence of environment and cholera toxin. International Archives of Allergy and Applied Immunology 91, 348—353. 

Kenworthy, A. K., Petranova, N. and Edidin, M. (2000). High resolution FRET microscopy of cholera toxin B-subunit and GPI-anchored proteins in cell plasma membranes. Mol. Biol. Cell 11, 1645-55. 

Rowe-Taitt C.A., Cras J.J., Patterson C.H., Golden J.P., Ligler F.S., A ganglioside-based assay for cholera toxin using an array biosensor, Anal. Biochem. 2000a 281 123-133. 

Fig. 9. Divalent GM1 mimic having high affinity against cholera toxin.125...

Fig. 22. Potent pentavalent D-galactosylamine inhibitors used by Fan s group for the cholera toxin B...

D. Arosio, M. Fontanella, L. Baldini, L. Mauri, A. Bemardi, A. Casnati, F. Sansone, and R. Ungaro, A synthetic divalent Cholera Toxin glycocalix[4] arene ligand having higher affinity than natural GM1 oligosaccharide, J. Am. Chem. Soc., 127 (2005) 3660-3661. 

I. A. Velter, M. Politi, C. Podlipnik, and F. Nicotra, Natural and synthetic cholera toxin antagonists, Mini-Rev. Med. Chem., 1 (2007) 159-170. 

A. Bemardi, L. Carrettoni, A. Grosso Ciponte, D. Montib, and S. Sonnino, Second generation mimics of ganglioside GM1 as artificial receptors for Cholera Toxin Replacement of the sialic acid moiety, Bioorg. Med. Chem. Lett., 10 (2000) 2197-2200. 

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