Premium
REPAIR OF THE SHELL IN SPECIES OF ANODONTA
Author(s) -
BEEDHAM G.E.
Publication year - 1965
Publication title -
proceedings of the zoological society of london
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0370-2774
DOI - 10.1111/j.1469-7998.1965.tb02003.x
Subject(s) - mantle (geology) , outer core , bacterial outer membrane , anatomy , geology , chemistry , materials science , composite material , biology , inner core , geochemistry , biochemistry , escherichia coli , gene
The process of shell repair in specios of Anodonta is re‐examined in the light of current views on the mantle/shell relationship in the Lamellibranchia. Experiments indicate that the epithelia of the general outer mantle surface and mantle isthmus normally responsible for the production, respectively, of the inner layer of the valves and of the ligament can regenerate material comparable with that produced by the outer fold of the mantle edge. The process, which is usually preceded by a phase in which amoebocytes are involved, consists initially of the formation of appreciable quantities of organic material (conchiolin). Much of this conchiolin is histochemically comparable with that of the periostracum and the outer layers of the valves and ligament secreted during marginal increment of the shell by the inner and outer surfaces, respectively, of the outer mantle fold. This type of conchiolin is probably rich in quinone‐tanned protein (sclerotin). Repair of the valves is completed by the calcification of this organic matrix to form an outer calcareous (prismatic) layer, followed by the desposition of inner (nacreous) layer material. During the repair process, the form of the general outer mantle epithelium tends to vary according to the type of material being secreted. While regenerating periostracal and outer shell layer components the epithelial cells of the general outer mantle surface and mantle isthmus resemble both histologically and histochemically those of the outer fold of the mantle edge. Completion of valve repair by the deposition of nacre is accompanied by the cells reverting to the form characteristic of the general mantle surface during normal shell growth. In Anodonta and related bivalves, therefore, the relationship which normally exists between the different shell layers and the secretory epithelial zones of the mantle does not appear to be specific and unalterable. The implications of these findings in relation to marginal growth of the mantle and shell are discussed.