| Abstract: | Replacement of starch with raffinose in Duncan and Strong sporulation medium improved percent sporulation in six of eight strains tested. Enterotoxin concentration in cell extracts was increased in the case of four of five known enterotoxin-positive strains. With strain NCTC 10240, levels of 0.3, 0.4, and 0.5% raffinose produced the highest enterotoxin concentration 300 to 320 micrograms of enterotoxin per mg of cell extract protein. At a level of 0.4% raffinose the highest enterotoxin concentration in cell extracts of NCTC 10240 occurred after 8 h of growth in Duncan and Strong medium. Enterotoxin produced in the presence of starch or raffinose by three separate strains all migrated at similar Rm by polyacrylamide gel electrophoresis. |
