Schwyn B, Neilands J B
Anal Biochem. 1987 Jan;160(1):47-56. doi: 10.1016/0003-2697(87)90612-9.
A universal method to detect and determine siderophores was developed by using their high affinity for iron(III). The ternary complex chrome azurol S/iron(III)/hexadecyltrimethylammonium bromide, with an extinction coefficient of approximately 100,000 M-1 cm-1 at 630 nm, serves as an indicator. When a strong chelator removes the iron from the dye, its color turns from blue to orange. Because of the high sensitivity, determination of siderophores in solution and their characterization by paper electrophoresis chromatography can be performed directly on supernatants of culture fluids. The method is also applicable to agar plates. Orange halos around the colonies on blue agar are indicative of siderophore excretion. It was demonstrated with Escherichia coli strains that biosynthetic, transport, and regulatory mutations in the enterobactin system are clearly distinguishable. The method was successfully used to screen mutants in the iron uptake system of two Rhizobium meliloti strains, DM5 and 1021.
利用铁载体对铁（III）的高亲和力，开发了一种检测和测定铁载体的通用方法。三元络合物铬天青S/铁（III）/十六烷基三甲基溴化铵在630nm处的消光系数约为100,000 M-1 cm-1，用作指示剂。当强螯合剂从染料中除去铁时，其颜色从蓝色变为橙色。由于灵敏度高，溶液中铁载体的测定及其通过纸电泳色谱法的表征可以直接在培养液的上清液上进行。该方法也适用于琼脂平板。蓝色琼脂上菌落周围的橙色晕圈表明铁载体的分泌。用大肠杆菌菌株证明，肠杆菌素系统中的生物合成、转运和调节突变是明显可区分的。该方法已成功用于筛选两株苜蓿根瘤菌DM5和1021铁摄取系统中的突变体。
