Pyoverdins

Ozonolysis of 5,8,9-trihydroxy-2,3-dihydro-l//-pyrimido[l, 2-n]quinoline-3-carboxylic acid (420), obtained from isopyoverdin isolated from Pseudomonas putida BTPl by acidic hydrolysis, gave l-2,4-diaminobutyric acid, which confirmed the hypothesis that heterocyclic chromophores 1 and 4 of pyoverdin and isopyoverdin, respectively, could have the same precursor, and the configuration at C(3) should be 5 (97ZN(C)549). 

A pyoverdin, containing chromophore 1, was coupled with different antibacterial fluoroquinoline-3-carboxylic acids (01JMC2139). 

Trihydroxy-2,3-dihydro-l//-pyrimido[l,2-u]quinoline-3-car-boxylic acid and (420) and its (15)-1-carboxylic acid isomer were isolated from isopyoverdins (97ZN(C)549, 01T1019) and pyoverdins (99MI27), respectively, after acidic hydrolysis in 3 M HCl for 5 days at 110°C. 

Inoue H, O Takimura, K Kawaguchi, T Nitoda, H Euse, K Murakami, Y Yamaoka (2003) Tin-carbon cleavage of organotin compounds by pyoverdine from Pseudomonas chlororaphis. Appl Environ Microbiol 69 878-883. 

Several studies have shown that ferrated pyoverdine-type siderophores can be used as iron sources for plants when added to soils (79,80). However, to date almost all attempts to supply iron to plants by inoculation of hydroponic solutions with siderophore-producing bacteria or by inoculating soils with pseudomonads have been unsuccessful (58,63,81). In experiments with cucumber, inoculation of a hydroponic medium with P. putida or with soil microorganisms and amend-... 

S. Buysens, K. Heungens, J. Poppe, and M. Hofte, Involvement of pyochelin and pyoverdin in suppression of Pyt/r/wm-induced damping-off of tomato by Pseudomo-na. i aeruginosa 7NSK2. Appl. Environ. Microbiol. 62 865 (1996). 

P. Marschner and D. E. Crowley, Iron stress and pyoverdin production by a fluo-... 

M. A. Abdallah, Pyoverdins and pseudobactins. CRC Handbook of Microbial Iron Chelates (G. Winkelmann, ed.) CRC Press, Boca Raton, 1991, pp. 139-154. 

M. Maurhofer, C. Hase, P. Meuwly, J. P. Metraus, and G. Defago, Induction of systemic resistance of tobacco necrosis virus by the root colonizing Pseudomonas fluorescens strain CHAO Influence of the gacA gene and of pyoverdine production. Phytopathology 54 139 (1994). 

Ar-quinolin-2-yl)imino]propionates by injection or sublimation at 530°C yielded a mixture of 3-amino- and 3-ethoxy-l//-pyrimido[l,2-rz]quinolin-l-ones <2004AJC577>. An oxidative cascade for the biomimetic formation of the pyoverdine chromophore was supported by incubation of 2-[(4-hydroxyphenyl)- and 2-[(2-(3,4-dihydroxipheny-l)ethyl]-l,4,5,6-tetrahydropyrimidines with polyphenol oxidase or Pseudomonas extract to afford a mixture of 8,9-dihydroxy-2,3-dihydro- and -2,3,5,6-tctrahydro-l //-pyrimido[ 1,2- ]quinolines <20030L2215>. Oxidation of 2-[(2-(3,4-dihydroxiphenyl)ethyl]-l,4,5,6-tetrahydropyrimidine with MnOz gave a similar result. 

Budzikiewicz, H., Schafer, M., Fernandez, D. U., Matthijs, S. and Cornelis, P. (2007). Characterization of the chromophores of pyoverdins and related siderophores by electrospray tandem mass spectrometry. Biometals 20, 135-44. 

One paradigm for membrane transport of iron is the binding of the receptor protein to an iron-free siderophore molecule, followed by exchange of iron from an external ferri-siderophore to the receptor bound iron-free siderophore, and subsequent transfer across the cellular membrane. This shuttle mechanism has been explored in the transport system of ferric pyoverdine in P. aeruginosa (215,216). It is unclear why the bacterial system behaves in this manner, but mutagenesis studies of the protein suggest that residues involved in the closure of the P-barrel will not interact in the same way with the iron-free siderophore as they do with the ferri-siderophore. A similar mechanism has been suggested for A hydrophila and E. coli (182). 

Chelators of iron, which are now widely applied for the treatment of patients with thalassemia and other pathologies associated with iron overload, are the intravenous chelator desferal (desferrioxamine) and oral chelator deferiprone (LI) (Figure 19.23, see also Chapter 31). Desferrioxamine (DFO) belongs to a class of natural compounds called siderophores produced by microorganisms. The antioxidant activity of DFO has been studied and compared with that of synthetic hydroxypyrid-4-nones (LI) and classic antioxidants (vitamin E). It is known that chronic iron overload in humans is associated with hepatocellular damage. Therefore, Morel et al. [370] studied the antioxidant effects of DFO, another siderophore pyoverdin, and hydroxypyrid-4-ones on lipid peroxidation in primary hepatocyte culture. These authors found that the efficacy of chelators to inhibit iron-stimulated lipid peroxidation in hepatocytes decreased in the range of DFO > hydroxypyrid-4-ones > pyoverdin. It seems that other siderophores are also less effective inhibitors of lipid peroxidation than DFO [371],... 

Wolz, C., Hohloch, K., Ocaktan, A., Poole, K., Evans, R. W., Rochel, N., Albrecht-Gary, A.-M., Abdallah, M. A. and Doering, G. (1994). Iron release from transferrin by pyoverdin and elastase from Pseudomonas aeruginosa, Infect. Immunol., 62, 4021 -027. 

Schalk, U., Hennard, C., Dugave, C., Poole, K., Abdallah, M. A. and Pattus, F. (2001). Iron-free pyoverdin binds to its outer membrane receptor FpvA in Pseudomonas aeruginosa, a new mechanism for membrane iron transport, Mol. Microbiol., 39, 351-360. 

Pyoverdin and other siderophores from bacteria-that mediate iron uptake... 

Obviously siderophores can be potent virulence factors of pathogenic bacteria. Siderophores in many cases have elaborate structures providing recognition only by the receptor site of the producing species. This renders a pirating by competing microorganisms more difficult. The structural specificities of siderophores have been used for classification purposes of bacterial species (see especially pyoverdins, Sect. 2.1). 

The most thoroughly investigated representatives are the pyoverdins, also spelled pyoverdines and occasionally named pseudobactins 353), produced by the fluorescent members of the genus Pseudomonas. For reviews see 44, 231) for a detailed... 

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