Search for microbial signatures within human and microbial calcifications using soft x-ray spectromicroscopy.

摘要: Background: The origin of advanced arterial and renal calcification remains poorly understood. Self-replicating, calcifying entities have been detected isolated from calcified human tissues, including blood vessels kidney stones, are referred to as nanobacteria. However, the microbiologic nature putative nanobacteria continues be debated, in part because difficulty discriminating biomineralized microbes minerals nucleated on anything else (eg, macromolecules, cell membranes). To address this controversy, use techniques capable characterizing organic mineral content these self-replicated structures at submicrometer scale would beneficial. Methods: Calcifying gram-negative bacteria (Caulobacter crescentus, Ramlibacter tataouinensis) used references self-replicating nanoparticles cultured samples aneurysms were examined using a scanning transmission x-ray microscope (STXM) Advanced Light Source Lawrence Berkeley National Laboratory. This uses monochromated focused synchrotron beam (80–2,200 eV) yield microscopic spectroscopic information both compounds 25 nm scale. Results: High-spatial energy resolution near-edge absorption fine structure (NEXAFS) spectra indicative elemental speciation acquired C K-edge, N Ca L2,3-edge single-cell C. crescentus R. tataouinensis displayed unique spectral signatures different that nonbiologic hydroxyapatite (Ca10(PO4)6(OH)2). Further, preliminary NEXAFS measurements calcium, carbon, nitrogen functional groups humans revealed evidence organics, likely peptides or proteins, specifically associated with minerals. Conclusion: Using spatial scale, it is possible define biochemical signature for bacteria, polysaccharides, nucleic acids, hydroxyapatite. These studies suggest share characteristics proteins. additional STXM work K-edge particular needed determine if they precipitated