Repression of phenolic acid-synthesizing enzymes and its relation to iron uptake in Bacillus subtilis.
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).
D001412:Bacillus subtilis / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D001565:Benzoates / Q000096:biosynthesis* / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D003470:Culture Media; D004794:Enzyme Repression / Q000187:drug effects*; D006877:Hydroxamic Acids / Q000378:metabolism; D007501:Iron / Q000378:metabolism* / Q000494:pharmacology; D007503:Iron Isotopes; D013431:Sulfates / Q000378:metabolism; D014364:Tryptophan; D014732:Vibration
D001565:Benzoates; D002712:Chlorides; D003470:Culture Media; D006877:Hydroxamic Acids; D007503:Iron Isotopes; D013431:Sulfates; D014364:Tryptophan; D007501:Iron