Unique three-dimensional structure of a fish pharyngeal jaw subjected to unusually high mechanical loads

Emeline Raguin*, Katya Rechav, Vlad Brumfeld, Ron Shahar, Steve Weiner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

We examine the structure of the bone of the pharyngeal jaws of a large fish, the black drum (Pogonias cromis), that uses its tooth-jaw complex to crush hard-shelled bivalve mollusks. During mastication huge compressive forces are concentrated in a tiny zone at the tooth-bone interface. We report on the structure of this bone, with emphasis on its contact with the teeth, at different hierarchical levels and in 3D. Micro-CT shows that the molariform teeth do not have roots and are supported by a circular narrow bony rim that surrounds the periphery of the tooth base. The lower pharyngeal jaw is highly porous, as seen by reflected light microscopy and secondary electron microscopy (SE-SEM). Porosity decreases close to the bone-tooth interface and back-scattered electron (BSE-SEM) microscopy shows a slight elevation in mineral density. Focused ion beam - scanning electron microscopy (FIB-SEM) in the serial surface view (SSV) mode reveals a most surprising organization at the nanoscale level: parallel arrays of mineralized collagen fibrils surrounding channels of ~100 nm diameter, both with their long axes oriented along the load direction. The channels are filled with organic matter. These fibril-channel arrays are surrounded by a highly disordered mineralized material. This unusual structure clearly functions efficiently under compression, but the precise way by which this unique arrangement achieves this function is unknown.

Original languageEnglish
Article number107530
JournalJournal of Structural Biology
Volume211
Issue number2
DOIs
StatePublished - 1 Aug 2020

Bibliographical note

Publisher Copyright:
© 2020 Elsevier Inc.

Keywords

  • Bone-tooth interface
  • FIB-SEM
  • Fish
  • Mineralized collagen

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