title: Effect of secondary metabolites on the organisms producing them: effect of nisin on Streptococcus lactis and enterotoxin B on Staphylococcus aureus.
abstract: The effect of secondary metabolites added to cultures of the organisms producing them was investigated. Nisin was added to growing cultures of a nisin-producing strain of Streptococcus lactis (354/07) and enterotoxin B to strains of Staphylococcus aureus (S6 and 243) producing enterotoxin B. One quarter (12 mug/ml) of the amount of nisin formed by the culture of S. lactis inhibited lag-phase cells and lysed log-phase cells. The same amount of nisin added before inoculation or at a time when nisin synthesis had started (in late log phase), caused only transient delay in growth. Inhibition of growth of the two enterotoxin B-producing strains of S. aureus could not be demonstrated at any stage of their growth cycle with as much as 1 mg of enterotoxin B per ml of medium.
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000494:pharmacology*; D003470:Culture Media; D004589:Electrophoresis, Disc; D004768:Enterotoxins / Q000096:biosynthesis / Q000494:pharmacology*; D013294:Lactococcus lactis / Q000187:drug effects / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology; D013210:Staphylococcus / Q000187:drug effects* / Q000378:metabolism; D013291:Streptococcus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D004768:Enterotoxins; D010455:Peptides