Clostridium septicum alpha-toxin is secreted as an inactive 46,450-Da protoxin. The protoxin is activated by proteolytic cleavage near the C terminus, which eventually causes the release of a 45-amino-acid fragment. Proteoytic activation and loss of the propeptide allow alpha-toxin to oligomerize and form pores on the plasma membrane, which results in colloidal-osmotic lysis. Activation may be ...

Clostridial glucosylating cytotoxins inactivate mammalian Rho GTPases by mono-O glucosylation of a conserved threonine residue located in the switch 1 region of the target protein. Here we report that EhRho1, a RhoA-like GTPase from the protozoan parasite Entamoeba histolytica, is glucosylated by clostridial cytotoxins. Recombinant glutathione S-transferase-EhRho1 and EhRho1 from cell lysate of...

Ultracentrifugal examination of staphylococcal alpha toxin at different stages of purification showed the presence of a major component having a sedimentation coefficient of 2.8S, present to the extent of more than 90% of the sample, and identifiable with active toxin. Several minor components having S(20,w) values of 11.5S, 8.5S, and 2.0S were detected. The 11.5S component presumably is identi...

Detoxification capacity of enzymes in the liver is thought to be the primary factor governing dietary toxin intake by mammalian herbivores. Recently, toxin absorption in the gut was proposed as an alternative process that also influences toxin intake. We examined the role of the gut in regulating toxin absorption by quantifying excretion of a plant secondary compound in the feces. We hypothesiz...

Enzymes known to specifically cleave the band 3 component of the rabbit erythrocyte membrane were found to reduce both the hemolytic sensitivity to and the binding of the alpha toxin of Staphylococcus aureus. Lectins which bind to band 3 also inhibited the toxin. Lectins which do not bind to band 3 have no effect. Purified band 3, isolated by affinity chromatography on a concanavalin A column, ...

in this research a molecular method based on polymerase chain reaction for typing of clostridium perfringens was developed and toxin genotypes of 64 isolates from sheep and goats in iran were determined. the pcr assays were developed for detection of alpha (cpa), beta (cpb) and epsilon (etx) toxin genes, allowing classification of the isolates into genotypes a b, c and d. the field isolates ...

BACKGROUND Cardiac performance is severely depressed in septic shock. Endotoxin has been implicated as the causative agent in Gram-negative sepsis, but similar abnormalities are encountered in Gram-positive sepsis. We investigated the influence of the major exotoxin of Staphylococcus aureus, staphylococcal alpha-toxin, in isolated perfused rat hearts. METHODS AND RESULTS Alpha-toxin 0.25 to 1...

1. Ketanserin may influence baroreflex function by blocking 5-HT(2A) receptors and/or alpha(1)-adrenoceptors through central and/or peripheral mechanisms. 2. In the present study, we tested the hypothesis that the baroreflex sensitivity (BRS)-enhancing effects of ketanserin are mediated by central 5-HT(2A) receptors in spontaneously hypertensive rats (SHR). 3. Using a conjugate of a monoclonal ...

Bordetella pertussis causes whooping cough, an endemic respiratory disease that is increasing in prevalence despite vaccination efforts. Although host immunity is modulated by virulence factors of this pathogen, it is unclear what host factors are required to overcome their effects. Here, we investigate an apparent relationship between the effects of pertussis toxin and tumor necrosis factor (T...