Factors influencing heat-labile Escherichia coli enterotoxin activity.
In this study, conditions for production, detection, and storage of heat-labile Escherichia coli enterotoxin (LT) in culture filtrates from E. coli H-10407 were defined by using the adrenal tumor cell assay system. An enriched medium containing 0.6% yeast extract, 2% Casamino Acids, and 0.25% glucose buffered at pH 8.5 produced the highest LT activity of the various test media. In E. coli strain H-10407, LT activity was markedly decreased if the initial pH of the culture media was reduced to pH 7.5 or less. In contrast to E. coli P-263, if strain H-10407 was grown in the presence of mitomycin C there was no increase in LT production. Crude-culture filtrates containing LT can be stored at 4 degrees C for several days without an appreciable loss of activity; however, for long-term storage lyophilization or freezing at -70 degrees C is recommended.
D003470:Culture Media; D004768:Enterotoxins / Q000032:analysis* / Q000096:biosynthesis; D004926:Escherichia coli / Q000254:growth & development; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008937:Mitomycins / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
D003470:Culture Media; D004768:Enterotoxins; D008937:Mitomycins