Crystallographic orientation and concentric layers in spicules of calcareous sponges

André Linhares Rossi, Bárbara Ribeiro, Moara Lemos, Jacques Werckmann, Radovan Borojevic, Jane Fromont, Michelle Klautau, Marcos Farina

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6 Scopus citations


In this work, the crystallography of calcareous sponges (Porifera) spicules and the organization pattern of the concentric layers present in their inner structure were investigated in 10 species of the subclass Calcaronea and three species of the subclass Calcinea. Polished spicules had specific concentric patterns that varied depending on the plane in which the spicules were sectioned. A 3D model of the concentric layers was created to interpret these patterns and the biomineralization process of the triactine spicules. The morphology of the spicules was compared with the crystallographic orientation of the calcite crystals by analyzing the Kikuchi diffraction patterns using a scanning electron microscope. Triactine spicules from the subclass Calcinea had actines (rays) elongated in the 〈2 1 0〉 direction, which is perpendicular to the c-axis. The scale spicules of the hypercalcified species Murrayona phanolepis presented the c-axis perpendicular to the plane of the scale, which is in accordance with the crystallography of all other Calcinea. The triactine spicules of the calcaronean species had approximately the same crystallographic orientation with the unpaired actine elongated in the ∼[2 1 1] direction. Only one Calcaronea species, whose triactine was regular, had a different orientation. Three different crystallographic orientations were found in diactines. Spicules with different morphologies, dimensions and positions in the sponge body had similar crystallographic directions suggesting that the crystallographic orientation of spicules in calcareous sponges is conserved through evolution.
Original languageEnglish (US)
Pages (from-to)164-172
Number of pages9
JournalJournal of Structural Biology
Issue number2
StatePublished - Nov 1 2016
Externally publishedYes

Bibliographical note

Generated from Scopus record by KAUST IRTS on 2023-10-23

ASJC Scopus subject areas

  • Structural Biology


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