title: Insights into the composition, morphology, and formation of the calcareous shell of the serpulid Hydroides dianthus.
abstract: To date, the calcareous tubes of serpulid marine worms have not been studied extensively in a biomineralization context. The structure and composition of the tube shell and adhesive cement of the marine tubeworm Hydroides dianthus were studied using a variety of characterization techniques, including powder XRD, FTIR, SEM, EDX, and AFM. The tube and cement were determined to be inorganic-organic composite materials, consisting of inorganic aragonite (CaCO(3)) and Mg-calcite ((Ca(0.8)Mg(0.2))CO(3)) crystals, and both soluble and insoluble organic matrices (SOM and IOM). SEM imaging revealed a variety of crystal morphologies. AFM nanoindentation of the inorganic components yielded Young's moduli of approximately 20GPa in the wet state, and approximately 50GPa in the dry state. Amino acid analysis of the SOM indicated substantial amounts of acidic and non-polar neutral amino acids. Part of the insoluble organic tube lining was identified as being composed of collagen-containing fibres aligned in a criss-crossed structure. The SOM and organic tube lining were found to contain carboxylated and sulphated polysaccharides. In an artificial seawater solution, the SOM and the organic tube lining mediated CaCO(3) mineralization in vitro.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, Canada M5S 3H6.
authors.forename: Adrienne E
authors.initials: AE
authors.lastname: Tanur
authors.forename: Nikhil
authors.initials: N
authors.lastname: Gunari
authors.forename: Ruby May A
authors.initials: RM
authors.lastname: Sullan
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kavanagh
authors.forename: Gilbert C
authors.initials: GC
authors.lastname: Walker
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000825:Animal Structures / Q000648:ultrastructure*; D000818:Animals; D002113:Calcification, Physiologic / Q000502:physiology*; D002119:Calcium Carbonate / Q000032:analysis; D002853:Chromatography, Liquid; D004577:Electron Probe Microanalysis; D005431:Florida; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D009024:Morphogenesis / Q000502:physiology*; D011077:Polychaeta / Q000033:anatomy & histology* / Q000502:physiology; D045483:Rivers; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D000596:Amino Acids; D002119:Calcium Carbonate