Specificity of pyoverdine-mediated iron uptake among fluorescent Pseudomonas strains

Abstract

Pyoverdine-mediated iron transport was determined for seven fluorescent Pseudomonas strains belonging to different species. For all strains, cell or cell outer membrane and iron(III)-pyoverdine combinations were compared with their homologous counterparts in uptake, binding, and cross-feeding experiments. For four strains (Pseudomonas putida ATCC 12633, Pseudomonas fluorescens W, P. fluorescens ATCC 17400, and Pseudomonas tolaasii NCPPB 2192), the pyoverdine-mediated iron transport appeared to be strictly strain specific; pyoverdine-facilitated iron uptake by iron-starved cells and binding of ferripyoverdine to the purified outer membranes of such cells were efficient only in the case of the homologous systems. Cross-feeding assays, in liquid or solid cultures, resulted, however, especially for P. fluorescens ATCC 17400, in some discrepancies compared with uptake and binding assays, suggesting that growth experiments are the least likely to yield correct information on specificity of the pyoverdine-mediated iron transport. For the three other strains (P.fluorescens ATCC 13525, P. chlororaphis ATCC 9446, and P. aeruginosa ATCC 15692), cross-reactivity was demonstrated by the uptake, binding, and cross-feeding experiments. In an attempt to determine which parts of the iron transport system were responsible for the specificity, the differences in amino acid composition of the pyoverdines, together with the differences observed at the level of the iron-sensitive outer membrane protein pattern of the seven strains, are discussed.

Ferrisiderophore reductases of Pseudomonas

“…stutzeri strain, immunodetection using the anti-(ferripyoverdine reductase) serum raised against the P. aeruginosa PA01 enzyme revealed a protein corresponding to the ferripyoverdine reductase of P. aeruginosa PA01 , suggesting that the same enzyme occurs regardless of the nature of the Pseudornonas strain and the siderophore it produces. The pyoverdines produced by the fluorescent strains represent at least seven chemically defined compounds, differing in the peptide moiety of the molecule (for the amino acid composition of these pyoverdines see [30] and [43]). P .…”

Vanadium interferes with siderophore-mediated iron uptake in Pseudomonas aeruginosa

“…The effects of adding the strong, non-metabolizable Fe(III) chelator EDDHA, the cognate purified PVD, and a heterologous PVD from P. aeruginosa ATCC 27853 for which PAO1 has no receptor (Hohnadel & Meyer, 1988), on the growth of PAO1 in CAA medium was tested after 24 h. As expected, addition of the cognate PVD (50 µM) in CAA medium stimulated growth (0n49 OD '!! units compared with 0n36 OD '!!…”

“…PVD (succinamide isoform) from P. aeruginosa PAO1 was isolated from CAA growth supernatants by the chloroform\phenol method followed by chromatography on CM-Sephadex and elution with 0n1 M pyrimidine\acetic acid buffer pH 5, as previously described (Hohnadel & Meyer, 1988). Eighty micromoles of the pure compound solubilized in 2 ml de-ionized water was supplemented with a slight excess of VOSO % ;5H # O (100 µmol) and then filtered through a Sephadex G25 column (2n5 i 45 cm) eluted with de-ionized water.…”

Temperature-sensitive production of azoverdin, the pyoverdin-like sid rophore of Azomonas macrocytogenes ATCC 12334

“…The difficulty in separating these related compounds was illustrated by gel filtration and ionexchange chromatography, in which several compounds with identical absorption spectra eluted as a single peak only to be resolved as different compounds by HPLC. In fact, some researchers may have overlooked this aspect of pyoverdin purification (Cody & Gross, 1987;Hohnadel & Meyer, 1988;Torres et al, 1986). The chemical structure of azoverdin is presently under investigation.…”