RT Journal Article SR Electronic(1) A1 Baysse, Christine A1 De Vos, Daniel A1 Naudet, Yann A1 Vandermonde, Alain A1 Ochsner, Urs A1 Meyer, Jean-Marie A1 Budzikiewicz, Herbert A1 Schäfer, Matthias A1 Fuchs, Regine A1 Cornelis, Pierre YR 2000 T1 Vanadium interferes with siderophore-mediated iron uptake in Pseudomonas aeruginosa JF Microbiology, VO 146 IS 10 SP 2425 OP 2434 DO https://doi.org/10.1099/00221287-146-10-2425 PB Microbiology Society, SN 1465-2080, AB Vanadium is a metal that under physiological conditions can exist in two oxidation states, V(IV) (vanadyl ion) and V(V) (vanadate ion). Here, it was demonstrated that both ions can form complexes with siderophores. Pseudomonas aeruginosa produces two siderophores under iron-limiting conditions, pyoverdine (PVD) and pyochelin (PCH). Vanadyl sulfate, at a concentration of 1–2 mM, strongly inhibited growth of P. aeruginosa PAO1, especially under conditions of severe iron limitation imposed by the presence of non-utilizable Fe(III) chelators. PVD-deficient mutants were more sensitive to vanadium than the wild-type, but addition of PVD did not stimulate their growth. Conversely, PCH-negative mutants were more resistant to vanadium than the wild-type strain. Both siderophores could bind and form complexes with vanadium after incubation with vanadyl sulfate (1:1, in the case of PVD; 2:1, in the case of PCH). Although only one complex with PVD, V(IV)–PVD, was found, both V(IV)– and V(V)–PCH were detected. V–PCH, but not V–PVD, caused strong growth reduction, resulting in a prolonged lag phase. Exposure of PAO1 cells to vanadium induced resistance to the superoxide-generating compound paraquat, and conversely, exposure to paraquat increased resistance to V(IV). Superoxide dismutase (SOD) activity of cells grown in the presence of V(IV) was augmented by a factor of two. Mutants deficient in the production of Fe-SOD (SodB) were particularly sensitive to vanadium, whilst sodA mutants deficient for Mn-SOD were only marginally affected. In conclusion, it is suggested that V–PCH catalyses a Fenton-type reaction whereby the toxic superoxide anion is generated, and that vanadium compromises PVD utilization., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-146-10-2425