TY - JOUR
T1 - Unique three-dimensional structure of a fish pharyngeal jaw subjected to unusually high mechanical loads
AU - Raguin, Emeline
AU - Rechav, Katya
AU - Brumfeld, Vlad
AU - Shahar, Ron
AU - Weiner, Steve
N1 - Publisher Copyright:
© 2020 Elsevier Inc.
PY - 2020/8/1
Y1 - 2020/8/1
N2 - 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.
AB - 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.
KW - Bone-tooth interface
KW - FIB-SEM
KW - Fish
KW - Mineralized collagen
UR - http://www.scopus.com/inward/record.url?scp=85084831249&partnerID=8YFLogxK
U2 - 10.1016/j.jsb.2020.107530
DO - 10.1016/j.jsb.2020.107530
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C2 - 32407760
AN - SCOPUS:85084831249
SN - 1047-8477
VL - 211
JO - Journal of Structural Biology
JF - Journal of Structural Biology
IS - 2
M1 - 107530
ER -