Logo image
Back
Simple spades or sophisticated shovels - the fine structure of chiton teeth
Abstract   Peer reviewed

Simple spades or sophisticated shovels - the fine structure of chiton teeth

D J Macey, Lesley R Brooker, R J Wealthall and Brendan J Griffin
Proceedings of the 2004 World Congress of Malacology, pp.89-90
World Congress of Malacology (WCM): Molluscan megadiversity: Sea, land and freshwater, 2004 (Perth, Australia, 2004)
2004
url
http://www.malsocaus.org/View
Webpage

Abstract

Biochemistry and Cell Biology radula teeth chiton
A range of scanning electron microscopes has been utilized to undertake a detailed in situ investigation of the fine structure of the major lateral teeth of the chiton Acanthopleura echinata. These teeth are composite structures comprising three distinct mineral zones: a posterior magnetite layer; a thin band of lepidopcrocite just anterior to this; and apatite throughout the core and anterior regions. Biomineralization in these teeth is a matrix-mediated process, in which the minerals are deposited around a complex series of fibres. The arrangement of the organic and biomineral components of the tooth is similar throughout the three zones, having no discrete borders between them, and with crystallites of each mineral phase extending into the adjacent mineral zone. Along the posterior surface of the tooth, the organic fibres are arranged in a series of fine parallel lines, but just within the perihery their appearance takes on a 'fish scale'-like pattern, reflective of the cross section of a series of units that are overlaid, and offset from each other, in adjacent rows and separated by organic fibres. Two types of subunits make up each 'fish scale'; one of which is elongated and curved, and forms a trough, in which the other, rod-like unit, is nestled. Adjacent units are aligned into large sheets that define the fracture of the tooth. The alignment of the plates of rod-trough units is complex and exhibits extreme spatial variation within the tooth cusp. Close to the posterior surface, the plates are essentially horizontal, and lie in a latero-medial plane, while anteriorly they are almost vertical and lie in the postero-anterior plane. An understanding of the fine structure of the mineralized teeth of chitons, and of the relationship between the organic and mineral components, provides a new insight into biomineralization mechanisms and controls.

Details

Metrics

1 File views/ downloads
419 Record Views
Logo image