Ellis Englesberg, Judith Bentoff Levy
1954 Journal of Bacteriology  
In the course of the development of a casein hydrolyzate mineral glucose medium for the growth of Pasteurella pestis, strain A1122, for the production of the envelope antigen (Englesberg and Levy, 1954) , the potential use of this medium for plague toxin production became apparent. The development of a simplified method for the production of plague toxin made possible by this medium will be described here. MATERLIALS AND METHODS Medium and cultural conditions. A casein hydrolyzate mineral
more » ... yzate mineral glucose medium of the following composition was employed: casamino acids (Difco), 3 per cent; glucose, 0.2 per cent; NH4Cl, 0.1 per cent; CaCl2, 1 X 10-3 per cent; FeCl,(6H20), 2.5 X 104 per cent; MgSO4(7H20), 0.05 per cent; Na2S2O8, 0.01 per cent. KH1P04 and Na2HPO4, pH 7, were added to yield a m/20 solution. Initially the medium was prepared as for the starting medium described previously (Englesberg and Levy, 1954). However, for the production of large quantities of toxin all components except glucose and phosphate buffer were autoclaved together, and thiosulfate was omitted. These changes did not interfere in any way with toxin production. One liter wide mouth Erlenmeyer flasks, each containing 250 ml of medium, were employed. The flasks were incubated at 30 C or 37 C as indicated, and aeration was provided by means of a shaking machine operating at 175 rpm with an eccentric of 1.5 cm. The inoculum, assay methods for total growth, total soluble antigen, and mouse intravenous toxicity tests were as previously described (Englesberg and Levy, 1954) . Organism. Pasteurella pesti, strain E.V.76, an avirulent, reportedly toxigenic strain Robic, 1936, 1942; Walker et al., 1953) ,
doi:10.1128/jb.68.1.57-60.1954 fatcat:ruq5hgyzpnfk7jux4dd4rbn7tm