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One Possible Iron Acquisition Pathway in Marine Bacteria

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  • One Possible Iron Acquisition Pathway in Marine Bacteria

    Greetings All !

    Here's an article I stumbled across a while ago ... thought it might be of interest to members and guests in ZeoVille.

    Self-Assembling Amphiphilic Siderophores from Marine Bacteria
    J. S. Martinez, G. P. Zhang, P. D. Holt, H.-T. Jung, C. J. Carrano, M. G. Haygood, Alison Butler

    Most aerobic bacteria secrete siderophores to facilitate iron acquisition. Two families of siderophores were isolated from strains belonging to two different genera of marine bacteria. The aquachelins, from Halomonas aquamarina strain DS40M3, and the marinobactins, from Marinobacter sp. strains DS40M6 and DS40M8, each contain a unique peptidic head group that coordinates iron(III) and an appendage of one of a series of fatty acid moieties. These siderophores have low critical micelle concentrations (CMCs). In the absence of iron, the marinobactins are present as micelles at concentrations exceeding their CMC; upon addition of iron(III), the micelles undergo a spontaneous phase change to form vesicles. These observations suggest that unique iron acquisition mechanisms may have evolved in marine bacteria.

    Science 18 February 2000:
    Vol. 287. no. 5456, pp. 1245 - 1247
    DOI: 10.1126/science.287.5456.1245

    Extracted from:
    You may need to register ... not to worry, it's painless.
    Fascinating stuff ... if you're interested in this kind of thing. Also has some cool graphics ...

    Fig. 1. The structures of the marinobactins and aquachelins. The vertical lines through the structures show the mass-to-charge ratio values for the y and b fragments obtained for marinobactin E and aquachelin D by tandem mass spectrometry. The "y" and "b" nomenclature refers to the charge when retained by the COOH-terminal fragment or the NH2-terminal fragment of the peptide, respectively (24).

    ... AND ... my favorite ...

    Fig. 3. Cryoelectron micrograph of Fe(III)-marinobactin D siderophore vesicles in aqueous solution. Representative vesicles are indicated by arrows. Samples were prepared for imaging by the method of Bellare et al. (27). The vesicles shown here result from 2 mM Fe(III)-marinobactins D in 100 mM tris-HCl (pH 8.0); the sample was rapidly frozen from a temperature of 25°C (28). The ratio of marinobactin D2 to D1 was about 3:1.

    Sometimes makes you wonder just how multi-dimensional the behavior of ZeoBak generated biofilms in a Zeo-Reactor might be, doesn't it?

    Acronym of the Day: HNLC. ("High Nutrient Low Chlorophyll")

    Just trying to fill in the data set ...

    "When the going gets weird, the weird turn pro."
    Hunter S. Thompson

  • #2
    Thnx. Gary, interesting correlations & the beat goes on Bob
    "There might be something to this ZEOvit"