conchiolin


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conchiolin

[käŋ′kī·ə·lən]
(biochemistry)
A nitrogenous substance that is the organic basis of many molluscan shells.
References in periodicals archive ?
Purification and characterization of calcium-binding conchiolin shell peptides from the mollusc, Haliotis rufescens, as a function of development.
Although the anti-naticid predation hypothesis has been widely accepted, alternative (potentially complementary) adaptational hypotheses for conchiolin layer function in corbulids have been proposed (Lewy and Samtleben 1979; Kat 1985; Harper 1994).
In this paper, I examine both the current utility and the adaptational history of conchiolin layers for the three proposed functions: retardation of shell dissolution, increase of mechanical shell strength, and inhibition of drilling by predatory naticid gastropods.
Corbulid shells characteristically contain within each valve at least one conchiolin layer that is accreted simultaneously with other microstructural layers (made of aragonite crystals and organic matrix) throughout most of the bivalve's life [ILLUSTRATION FOR FIGURE 2 OMITTED].
Briefly, the 7 conchiolin deposit stages (CDS) ranged from microscopic brown spots on the inner face of the shell during the earliest stage (CDSI), to a thick brown deposit covering most of the inner shell during the most advanced stage (CDS7).
The first phase corresponds to the development of the disease and is characterized only by accumulation of conchiolin deposit.
Disease intensity was estimated by the extent of the symptomatic deposit according to the criteria of Paillard and Maes (1994), in which conchiolin deposit stages (CDS) range from a microscopic brown spot on the inner face of the shell in the earliest stages (CDS 1) to a thick brown deposit covering most of the inner shell in the most advanced stage (CDS 7).
The stage of progression of BRD on the shell valves was monitored according to the classification system of Paillard & Maes (1994), in which the syndrome is characterized by two stages, which may occur simultaneously in a given individual: a conchiolin deposit stage (CDS), in which layers of an organic conchiolin deposit are laid down between the mantle edge and periostracal lamina, and a shell repair stage (SRS), in which the clam lays down layers of shell on top of the conchiolin deposit, for repair and recovery from the disease.
Two individuals, who displayed brown conchiolin deposits, went undetected for V.
The burrows are not often seen to penetrate the inner surface of their host's shell and do not have any direct contact with the host animal, but this seems to be because the burrowing activity induces the host to secrete a protective layer of dark conchiolin, followed by a nacreous shell layer, on the inside of the shell (Haigler 1969, Kent 1979, Blake 1996, Marshall & Day 2001).
The growth of shell results from the deposition of crystal line material within an organic matrix of conchiolin by a thin sheet of tissue called the mantle, which lines the inner surface of the shell.
radiata, that both conchiolin formation and crystallization can occur without direct contact with mantle epithelial cells.