The phospholipases C of C. perfringens (alpha-toxin) and C. bifermentans (Cbp) show >50% amino acid homology but differ in their hemolytic and toxic properties. We report here the purification and characterisation of alpha-toxin and Cbp. The phospholipase C activity of alpha-toxin and Cbp was similar when tested with phosphatidylcholine in egg yolk or in liposomes. However, the hemolytic activi...

McClatchy, J. K. (The University of Texas Southwestern Medical School, Dallas), and E. D. Rosenblum. Biological properties of alpha-toxin mutants of Staphylococcus aureus. J. Bacteriol. 92:575-579. 1966.-Twenty nonhemolytic mutants of Staphylococcus aureus were isolated after treatment of a hemolytic strain with ultraviolet light or nitrous acid. Thirteen strains isolated were completely lackin...

Clostridium perfringens alpha-toxin elicits various immune responses such as the release of cytokines, chemokines, and superoxide via the GM1a/TrkA complex. Alpha-toxin possesses phospholipase C (PLC) hydrolytic activity that contributes to signal transduction in the pathogenesis of gas gangrene. Little is known about the relationship between lipid metabolism and TrkA activation by alpha-toxin....

Septic arthritis is a common and feared complication of staphylococcal infections. Staphylococcus aureus produces a number of potential virulence factors including certain adhesins and enterotoxins. In this study we have assessed the roles of cytolytic toxins in the development of septic arthritis by inoculating mice with S. aureus wild-type strain 8325-4 or isogenic mutants differing in the ex...

OBJECTIVES This study examines the efficacy of FTY720 (FTY), a new immunosuppressor, in the treatment of acute viral myocarditis in a murine model. BACKGROUND Immunosuppressive agents have no proven therapeutic efficacy in experimental or clinical myocarditis. METHODS Encephalomyocarditis virus was inoculated i.p. in DBA/2 mice on day 0. Postinoculation treatment consisted of FTY 10 mg/kg/d...

The contact site A (csA) glycoprotein is a strictly developmentally regulated plasma membrane component responsible for the EDTA-stable (Ca(2+)-independent) form of intercellular adhesion in Dictyostelium discoideum. Using inverse polymerase chain reaction and a terminator vector we have isolated a 1.6 kb genomic fragment carrying a 1.1 kb upstream region of the csA gene. This fragment had prom...

The effect of several recombinant cytokines, including interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, and IL-1 alpha, on megakaryocyte (MK) colony formation by a normal human bone marrow subpopulation (CD34+ DR+), enriched for the MK colony-forming unit (CFU-MK), was studied using a serum-depleted, fibrin clot culture system. IL-3 and GM-CSF, but not IL-6...

Beta-toxin is one of the lethal toxins of Clostridium perfringens. It shares sequence homology with the pore-forming alpha-toxin of Staphylococcus aureus and structural homology has been indicated by mutagenesis studies. Human endothelial cells are sensitive to the toxic effect of alpha-toxin and in order to investigate the function of beta-toxin we have looked at the effect of the protein on h...

The ability to selectively disrupt gene function remains a critical element in elucidating information regarding gene essentiality for bacterial growth and/or pathogenesis. In this study, we adapted a tet regulatory expression system for use in Staphylococcus aureus, with the goal of downregulating gene expression via induction of antisense RNA. We demonstrate that this system exhibits a 50- to...

N-Formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe) and leukotriene B4 (LTB4) induce disparate second-messenger generation and functional responses in neutrophils and HL-60 granulocytes. Receptors for these chemoattractants couple to a common pool of G-proteins which are substrates for both pertussis-toxin- and cholera-toxin-catalysed ADP-ribosylation. The hypothesis that formyl-peptide and L...