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  • IsdC from Staphylococcus lugdunensis induces biofilm formation under low-iron growth conditions.

IsdC from Staphylococcus lugdunensis induces biofilm formation under low-iron growth conditions.

Infection and immunity (2014-04-02)
Antonino Missineo, Antonella Di Poto, Joan A Geoghegan, Simonetta Rindi, Simon Heilbronner, Valentina Gianotti, Carla Renata Arciola, Timothy J Foster, Pietro Speziale, Giampiero Pietrocola
ABSTRACT

Staphylococcus lugdunensis is a coagulase-negative staphylococcus that is a commensal of humans and an opportunistic pathogen. It can cause a spectrum of infections, including those that are associated with the ability to form biofilm, such as occurs with endocarditis or indwelling medical devices. The genome sequences of two strains revealed the presence of orthologues of the ica genes that are responsible for synthesis of poly-N-acetylglucosamine (PNAG) that is commonly associated with biofilm in other staphylococci. However, we discovered that biofilm formed by a panel of S. lugdunensis isolates growing in iron-restricted medium was susceptible to degradation by proteases and not by metaperiodate, suggesting that the biofilm matrix comprised proteins and not PNAG. When the iron concentration was raised to 1 mM biofilm formation by all strains tested was greatly reduced. A mutant of strain N920143 lacking the entire locus that encodes iron-regulated surface determinant (Isd) proteins was defective in biofilm formation under iron-limited conditions. An IsdC-null mutant was defective, whereas IsdK, IsdJ, and IsdB mutants formed biofilm to the same level as the parental strain. Expression of IsdC was required both for the primary attachment to unconditioned polystyrene and for the accumulation phase of biofilm involving cell-cell interactions. Purified recombinant IsdC protein formed dimers in solution and Lactococcus lactis cells expressing only IsdC adhered to immobilized recombinant IsdC but not to IsdJ, IsdK, or IsdB. This is consistent with a specific homophilic interaction between IsdC molecules on neighboring cells contributing to accumulation of S. lugdunensis biofilm in vivo.

MATERIALS
Product Number
Brand
Product Description

Iron, IRMM®, certified reference material, 0.5 mm wire
Sigma-Aldrich
Iron, puriss. p.a., carbonyl-Iron powder, low in magnesium and manganese compounds, ≥99.5% (RT)
Sigma-Aldrich
Iron, foil, thickness 0.1 mm, ≥99.9% trace metals basis
Sigma-Aldrich
Iron, chips, 99.98% trace metals basis
Sigma-Aldrich
Iron, powder, −325 mesh, 97%
Iron, foil, not light tested, 100x100mm, thickness 0.006mm, 99.85%
Iron, rod, 100mm, diameter 5.0mm, as drawn, 99.99+%
Iron, foil, 150x150mm, thickness 2.0mm, as rolled, armco« soft ingot 99.8%
Iron, microfoil, disks, 25mm, thinness 0.05μm, specific density 40.44μg/cm2, permanent mylar 3.5μm support, 99.99+%
Iron, foil, not light tested, 50x50mm, thickness 0.003mm, 99.85%
Iron, foil, 100x100mm, thickness 0.125mm, as rolled, 99.99+%
Iron, rod, 50mm, diameter 100mm, as drawn, armcO« soft ingot 99.8%
Iron, rod, 1000mm, diameter 30mm, as drawn, 98+%
Iron, rod, 500mm, diameter 12.7mm, as drawn, 99.95%
Iron, rod, 500mm, diameter 19mm, as drawn, soft ingot 99.8%
Iron, rod, 100mm, diameter 50mm, as drawn, 98+%
Iron, foil, light tested, 25x25mm, thickness 0.075mm, hard, 99.5%
Iron, foil, 25x25mm, thickness 0.25mm, hard, 99.5%
Iron, foil, 300x300mm, thickness 0.20mm, hard, 99.5%
Iron, tube, 1000mm, outside diameter 3.2mm, inside diameter 2.2mm, wall thickness 0.5mm, as drawn, 99.8%
Iron, rod, 500mm, diameter 30mm, as drawn, armcO« soft ingot 99.8%
Iron, rod, 500mm, diameter 9.5mm, as drawn, 98+%
Iron, foil, 10mm disks, thickness 0.003mm, 99.85%
Iron, tube, 500mm, outside diameter 2.38mm, inside diameter 1.6mm, wall thickness 0.39mm, as drawn, 99.8+%
Iron, tube, 200mm, outside diameter 3.18mm, inside diameter 1.96mm, wall thickness 0.61mm, as drawn, 99.5%
Iron, rod, 100mm, diameter 40mm, as drawn, armcO« soft ingot 99.8%
Iron, rod, 1000mm, diameter 19.0mm, as drawn, 98+%
Iron, rod, 200mm, diameter 30mm, as drawn, 98+%
Iron, foil, 50x50mm, thickness 0.125mm, as rolled, 99.99+%
Iron, tube, 100mm, outside diameter 10.6mm, inside diameter 10.0mm, wall thickness 0.3mm, as drawn, 99.8+%