EFFECT OF PHOSPHATE ON COLICIN V FORMATION BY STRAINS OF ESCHERICHIA COLI / 微生物学通报

ColV~+ strains of Escherichia coli produced larger inhibitory zones when these strains grown on nutrient agar containing phosphate after overlaid sensitive indicators. This appears that production of colicin V is increased by the addition of phosphate to nutrient agar. It was sure that stimulation of phosphate to colicin V formation results from its effect in reducing divalent cation levels in nutrient agar since adding EDTA to nutrient agar had the same effect as phosphate, but the addition of Mg~(2+) or Ca~(2+) had the oppsite effect. Therefore nutrient agar supplemented with phosphate can be used to isolate and identificate ColV~+ strains of E. coli.