Activity of the Bacillus anthracis 20 kDa protective antigen component.

Background: Anthrax is caused by Bacillus anthracis that produce two exotoxins, lethal toxin and edema toxin. The lethal toxin is composed of the lethal factor (LF) complexed with the cell binding protective antigen (PA83, 83 kDa). Likewise, the edema factor (EF) binds to the PA83 to form the edema toxin.

A selective reaction of fructose bisphosphate aldolase with fluorescein isothiocyanate in chicken muscle extracts.

The present work describes the selective covalent modification of fructose bisphosphate aldolase in crude extracts of chicken breast muscle by fluorescein 5'-isothiocyanate (5'-FITC) at pH 7.0 and 35 degrees C. The modification was observed after 1 min while no other major soluble protein was labeled even after 30 min.

Purified Bacillus anthracis lethal toxin complex formed in vitro and during infection exhibits functional and biological activity.

Anthrax protective antigen (PA, 83 kDa), a pore-forming protein, upon protease activation to 63 kDa (PA(63)), translocates lethal factor (LF) and edema factor (EF) from endosomes into the cytosol of the cell. The relatively small size of the heptameric PA(63) pore (approximately 12 angstroms) raises questions as to how large molecules such as LF and EF can move through the pore. In addition, the reported high binding affinity between PA and EF/LF suggests that EF/LF may not dissociate but remain complexed with activated PA(63).

A two-component direct fluorescent-antibody assay for rapid identification of Bacillus anthracis.

A two-component direct fluorescent-antibody (DFA) assay, using fluorescein-labeled monoclonal antibodies specific to the Bacillus anthracis cell wall (CW-DFA) and capsule (CAP-DFA) antigens, was evaluated and validated for rapid identification of B. anthracis. We analyzed 230 B.