ISSN:
1432-136X
Keywords:
Chitin
;
Aragonite
;
Calcification
;
Crystalline shape
;
Anodonta cygnea
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary An orthorhombic structure α-chitin, probably in the form of a chitin-protein complex, was identified in the matrix of the shell of Anodonta cygnea by X-ray diffraction. Aragonite crystals of pseudohexagonal symmetry were also found by a Lauegram on the nacreous layer of the shell. The orthorhombic structure of these two compounds together with the identical reticular spacing d110 corroborate, in Anodonta cygnea, the indirect chitin-aragonite relationships already suggested for molluscan shells. Observations with SEM in the inner surface of the shell showed CaCO3 crystals with irregular geometrical shapes in spring and summer and regular geometrical shapes in autumn and winter. The more elaborate aspect appearing in winter corresponds to an accurate hexagonal shape. This suggests that the observed variability may depend on the balance between calcium and hydrogen ions in the extrapallial fluid.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00260802
