Showing papers on "Bacillus anthracis published in 1982"

Anthrax toxin edema factor: a bacterial adenylate cyclase that increases cyclic AMP concentrations of eukaryotic cells.

Abstract: Anthrax toxin is composed of three proteins: protective antigen (PA), lethal factor (LF), and edema factor (EF). These proteins individually cause no known physiological effects in animals but in pairs produce two toxic actions. Injection of PA with LF causes death of rats in 60 min, whereas PA with EF causes edema in the skin of rabbits and guinea pigs. The mechanisms of action of these proteins have not been determined. It is shown here that EF is an adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] produced by Bacillus anthracis in an inactive form. Activation occurs upon contact with a heat-stable eukaryotic cell material. The specific activity of the resulting adenylate cyclase nearly equals that of the most active known cyclase. In Chinese hamster ovary cells exposed to PA and EF, cAMP concentrations increase without a lag to values about 200-fold above normal, remain high in the continued presence of toxin, and decrease rapidly after its removal. The increase in cAMP is completely blocked by excess LF. It is suggested that PA interacts with cells to form a receptor system by which EF and perhaps LF gain access to the cytoplasm.

Assessment of immunofluorescence measurements of individual bacteria in direct and indirect assays for Bacillus anthracis and Bacillus cereus spores

Abstract: A microfluorometer constructed by the addition of fibre optics to a standard fluorescence microscope has been used in immunofluorescence assays for spores of Bacillus anthracis and B. cereus. Variation in the fluorescence measurements of individual anthrax spores increased as the amount of conjugate bound increased. Proportionality of photodetector voltage and amount of bound conjugate is suggested by results with a dual fluorescein/tritium-labelled antibody. The maximum fluorescence signal which could be achieved in indirect assays was virtually independent of the purity of the antispore antibody. Evidence is presented that the molecular loading of conjugate on the spore surface is similar in the direct and indirect assays.

Anthrax-specific "AP 50-like" phages isolated from Bacillus cereus strains.

Abstract: Phages exerting a specific action on Bacillus anthracis were isolated from mitomycin C-induced concentrated lysates of 5 Bacillus cereus strains producing megacin A (phospholipase A). In electron micrographs the phages closely resembled the anthrax-specific, lipid containing phage AP 50 isolated earlier from soil sample. The phages were similar to AP 50 also in their antigenic and chemical structure, host range and sensitivity to organic solvents, detergents and caesium chloride. The DNA character of AP 50 nucleic acid was shown by agarose gel electrophoresis. AP 50 and related phages seem to represent a separate group of phages acting on Bacillus strains.

Production of High Levels of Bacillus Anthracis Toxin Antigens in a New, Defined Culture Medium

Abstract: : Improved cultural conditions and a new, completely synthetic medium (R medium) were developed to facilitate the production of Bacillus anthracis holotoxin antigens. Levels of these antigens, up to five-fold greater than the highest previously reported values, have been produced using the described system. The R medium was shown to be superior to 1095 and casamino acids media for the elaboration of lethal factor and protective antigen. The Sterne, V770-NP1-R, and Vollum 1B strains of B. anthracis were cultured for 42 h in R medium. Growth, pH change, glucose utilization, and supernatant protein concentration, lethal toxin activity and protease activity were monitored during this period. Lethal toxin production in all three strains was first detectable in late log phase and reached its maximum level during the stationary phase. Proteolytic activity, presumably responsible for degradation of the toxin, was detected in the supernatants of all three strains.

Rapid Methods for the Laboratory Identification of Pathogenic Microorganisms.

Abstract: : Our studies to date have demonstrated the potential for developing a field-type kit for the rapid identification of Bacillus anthracis We have shown that certain lectins will selectively interact with B anthracis, but not with other species of the Bacillus genus This finding provides the basis for devising more sensitive assays, such as an enzyme-linked lectinosorbent test A most significant observation is the fact B anthracis spores also exhibited a similar lectin specificity Originator-supplied key words include: Lectins; Rapid identification; Bacillus anthracis; Cryptococcus neoformans; Neisseria meningitidis