Mechanisms of Toxin Production of Food Bacteria (Clostridium botulinum)
2006
Eklund, Melvin W. | Poysky, Frank T. | Peterson, Mark E.
The purpose of these studies was to determine the mechanisms governing the toxigenicity of food bacteria such as Clostridium botulinum and closely related organisms. Results from these studies show that C. botulinum types C and D cease to produce their dominant toxins when they are cured of their prophages. These nontoxigenic derivatives then become sensitive to bacteriophages of other cultures which induce the production of different toxins. One cured strain of type C was shown to be sensitive to bacteriophages from C. botulinum types C and D and C. novyi type A. These bacteriophages in duced the production of toxin of C. botulinum type C and D or the alpha toxin of C. novyi, respectively. This same cured type C strain could simultaneously carry bacteriophages of type C and C. novyi type A or type D and C. novyi type A which simultaneously induced the production of both C. novyi alpha and botulinum toxins. When type C and D cultures were cured of their prophages, then minor toxins previously masked by the dominant toxins could be detected. As a result, types C and D can each be subdivided into eight subtypes based upon the different toxin combinations. Only two subtypes of type C and one subtype of type D were previously recognized. C. botulinum type A and F strains have been cured of their prophages but they continue to produce toxin. Certain strains of nonproteolytic type B have ceased to produce toxin when they are cultured in medium containing acridine orange, but these strains are not sensitive to bacteriophages. Plasmids have been detected in these strains of types A, F, and B but the role these plasmids play is not known.
显示更多 [+] 显示较少 [-]