October 2004 Archives

Argonne research group recently published details of their successful application of high-spatial-resolution XRF and XAFS measurements, which they performed in order to make elemental maps and qualitative chemical analyses of single free-floating, or planktonic, and surface-adhered, or biofilm, cells of Pseudomonas fluorescens. The results revealed differences between the planktonic and biofilm cells in terms of morphology, elemental composition and sensitivity to hexavalent chromium, a heavy-metal contaminant and a known carcinogen. The biofilm cells were more tolerant of the contaminant, which damaged or killed the planktonic cells. The experiments were performed with a 150 nm X-ray beam produced by phase zone plate at the beamline XOR 2-ID, at the Advanced Photon Source (APS), Argonne, USA. For more information, see the paper, "Elemental and Redox Analysis of Single Bacterial Cells by X-ray Microbeam Analysis", K. M. Kemner et al., Science, 306, 686-687 (2004).