Stability Constants of Pseudobactin Complexes with Transition Metals

Chen, Yona; Jurkevitch, Édouard; Bar-Ness, E.; Hadar, Yitzhak

doi:10.2136/sssaj1994.03615995005800020021x

Cited by 53 publications

(31 citation statements)

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“…PSB has a K,,, of 22.5 at pH 6.0, 25"C, and 0.1 M ionic strength (Chen et al, 1994). It was found that ligand exchange from FePSB to MA did not occur at all, whereas a complete exchange from FeMA to PSB occurred with a half-life of 2 h (Jurkevitch et al, 1993).…”

Section: Discussionmentioning

confidence: 95%

The Role of Ligand Exchange in the Uptake of Iron from Microbial Siderophores by Gramineous Plants

et al. 1996

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Section: Discussionmentioning

confidence: 95%

The Role of Ligand Exchange in the Uptake of Iron from Microbial Siderophores by Gramineous Plants

et al. 1996

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“…This is not surprising since it is well established that vanadium can be liganded by hydroxamates, carboxylates and catecholates (Keller et al, 1991 ;Rehder, 1991). Others have also demonstrated the fact that PVD, as well as PCH, can complex copper, zinc or manganese (Poppe et al, 1987 ;Chen et al, 1994 ;Visca et al, 1992 ;Bouby et al, 1999). Visca et al (1992) suggested that PCH could play a role in the acquisition of metals other than Fe(III), such as Co(II) and Mo(VI).…”

Section: Discussionmentioning

confidence: 96%

Vanadium interferes with siderophore-mediated iron uptake in Pseudomonas aeruginosa

et al. 2000

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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 ; :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, causedstrong 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 O N 2 is generated, and that vanadium compromises PVD utilization.

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“…monads has increased recently because of the possible use of siderophores as biopesticides (Wilson, 1997) and the possible use of pseudomonads in detoxifying chemical wastes through a wide range of enzymatic metabolic activities (Raaijmakers, 1995). Iron metabolism has also been studied because of the potential role of microbial siderophores in facilitating uptake of heavy metals and their mobilisation under certain growth conditions (Chen et al,1994;Mench et al, 1994 ). Here, we have investigated the specific stimuli for siderophores production in local strains of P. fluorescens under different Fe (III) concentrations in the presence of various carbon sources.…”

Section: Introductionmentioning

confidence: 99%

Effect of iron and growth inhibitors on siderophores production by Pseudomonas fluorescens

Rachid¹,

Bensoltane²

2005

Afr. J. Biotechnol.

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The ability of Pseudomonas to grow and to produce siderophores is dependent on the iron content and the type of carbon sources in the medium. Under conditions of low-iron concentration the Pseudomonas isolates studied produced yellow-green fluorescent iron-binding peptide siderophores and the biosynthesis of this siderophores was affected by several different environmental parameters. Four basal media, supplemented with different concentration of iron, were employed to study the effect of iron and different organic carbon sources on siderophore production in Pseudomonas fluorescens. The highest siderophores concentration was obtained in succinate medium. Ferric iron increased the growth yield and completely repressed siderophores production above 200 g/l, but had a positive effect below 160 g/l. Penicillin and lead elicited the production of siderophores in the presence of excess iron. Pre-treatment of the standard succinate medium with α α α α,α α α α-dipyridyl and 8-hydroxyquinoline to reduce the concentration of iron diminished both the growth yield and siderophore production, but α α α α,α α α α-dipyridyl increased significantly the amount of siderophores produced in the presence of 0.20 mg/l of the chelating ion.

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Stability Constants of Pseudobactin Complexes with Transition Metals

Cited by 53 publications

References 0 publications

The Role of Ligand Exchange in the Uptake of Iron from Microbial Siderophores by Gramineous Plants

The Role of Ligand Exchange in the Uptake of Iron from Microbial Siderophores by Gramineous Plants

Vanadium interferes with siderophore-mediated iron uptake in Pseudomonas aeruginosa

Effect of iron and growth inhibitors on siderophores production by Pseudomonas fluorescens

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