Downer D N, Davis W B, Byers B R
J Bacteriol. 1970 Jan;101(1):181-7. doi: 10.1128/jb.101.1.181-187.1970.
Excretion of the metal-chelating phenolic acid, 2,3-dihydroxybenzoate, by a tryptophan-requiring strain (M-13) of Bacillus subtilis was inversely proportional to the iron added to the medium. Addition of iron as the ferric chelates of two secondary hydroxamates (ferri-schizokinen and Desferal) markedly reduced excretion. Synthesis of 2,3-dihydroxybenzoate from chorismate by extracts of B. subtilis M-13, grown in low-iron medium, was unaltered by additions of FeSO(4), FeCl(3), ferrischizokinen, 2,3-dihydroxybenzoate, the 2,3-dihydroxybenzoate-iron complex, or by extracts of cells grown in high-iron medium (which contained no demonstrable 2,3-dihydroxybenzoate-synthesizing activity) to the extracts of "low-iron cells." Iron control seemed to involve repression of synthesis of the enzymes in the 2,3-dihydroxybenzoate pathway. Both ferri-schizokinen and 2,3-dihydroxybenzoate plus iron enhanced considerably the otherwise minimal repressive effects of iron at low concentrations. Ferri-schizokinen delayed derepression of the pathway in B. subtilis M-13, and reduced its rate of synthesis after derepression. Addition of FeSO(4) to derepressed cells of B. subtilis M-13 halted synthesis of the enzymes after a lag period. The effect of the ferric hydroxamates was related to the capacity of B. subtilis M-13 to incorporate (59)Fe(3+) from Desferal-(59)Fe(3+). Cellular accumulation of (59)Fe(3+) from Desferal-(59)Fe(3+) after 20 min was nearly double that incorporated from (59)FeCl(3).
枯草芽孢杆菌的色氨酸需求菌株（M-13）对金属螯合酚酸2,3-二羟基苯甲酸的排泄与添加到培养基中的铁呈反比。添加作为两种二级异羟肟酸铁螯合物（铁裂褶菌素和去铁胺）的铁显著降低了排泄。在低铁培养基中生长的枯草芽孢杆菌M-13提取物由分支酸合成2,3-二羟基苯甲酸，不受添加硫酸亚铁、氯化铁、铁裂褶菌素、2,3-二羟基苯甲酸、2,3-二羟基苯甲酸-铁络合物的影响，也不受在高铁培养基中生长的细胞提取物（其中不含可证明的2,3-二羟基苯甲酸合成活性）添加到“低铁细胞”提取物中的影响。铁调控似乎涉及对2,3-二羟基苯甲酸途径中酶合成的抑制。铁裂褶菌素和2,3-二羟基苯甲酸加铁在低浓度时大大增强了铁原本最小的抑制作用。铁裂褶菌素延迟了枯草芽孢杆菌M-13中该途径的去抑制，并降低了去抑制后其合成速率。向枯草芽孢杆菌M-13的去抑制细胞中添加硫酸亚铁在延迟期后停止了酶的合成。异羟肟酸铁的作用与枯草芽孢杆菌M-13从去铁胺-(59)Fe(3+)中摄取(59)Fe(3+)的能力有关。20分钟后从去铁胺-(59)Fe(3+)中摄取的(59)Fe(3+)的细胞积累量几乎是从(59)FeCl(3)中摄取量的两倍。
