The condition was characterized by the presence of rigid blisters of shell and conchiolin
materials at the myostracal surface of adductor muscle attachment to the valves, which contained brownish, viscous liquid.
The core of those structures is made of a protein called conchiolin
, a common component of many mollusk shells.
It coats an irritant - such as a grain of sand - with layers of aragonite and conchiolin
, and the composite material is called nacre.
If the mollusc is unable to get rid of the irritant, as part of its defence mechanism it produces conchiolin
(an organic glue) and nacre (calcium carbonate crystallised in the form of aragonite).
BRD symptoms in adult animals resulting from conchiolin
deposits in inner parts of carpet shell were observed in all zones surveyed.
covered with nacre) that projected into the mantle cavity to isolate the shell-boring polychaetes.
ABSTRACT Brown ring disease (BRD) in the Manila clam is characterized by the formation of a brown deposit of conchiolin
on the inner surface of the shell that gives the disease its name.
These cavities are filled with calcium carbonate (aragonite) crystals perpendicularly to the outer periostracum and separated by a conchiolin
The deep, multilayered, cup-shaped lower valve is cemented to the substratum and the thin, flat upper valve is usually marked with fine radially striated conchiolin
externally (Kilburn & Rippey 1982).
Evidence from the fossil record of an antipredatory exaptation: conchiolin
layers in corbulid bivalves.
BMD induces a transformation of the posterior adductor muscle, which becomes infused by conchiolin
and calcified (Dang et al.
Previous research has shown that the periodic growth structures contained within molluscan shells develop from changes in the density of calcium carbonate, the ratio of aragonite to calcite, the proportion of calcium carbonate to conchiolin
(the organic component of the shell), the size of the crystals, or the type of crystalline microstructure (Pannella & MacClintock 1968, Rhoads & Lutz 1980, Jones 1983).