Journal ArticleDOI
Intracellular crystal-bearing vesicles in the epidermis of scleractinian corals, Astrangia danae (Agassiz) and Porites porites (Pallas).
Raymond L. Hayes,Nora I. Goreau +1 more
TLDR
Identification of the primordial crystal population within membrane-bound visicles provides overwhelming evidence for the intracellular mode of calcification in Scleractinia and permits development of a novel concept of cellular regulation over these dynamic events.Abstract:
Orthorhombic aragonitic crystals, embedded with a granular lipo-protein matrix and surrounded by a trilaminar membrane, are localized in the apical cytoplasm of epidermal cells of Scleractinian corals. Adult specimens of Astrangia danae (Agassiz) and settled planulae of Porites porites (Pallas) contain crystals averaging 0.7 mu by 0.1 mu by 0.3 mu within Golgi-derived vesicles. Short-term labelling with 45Ca reveals distribution of radioactivity amont a basic tissue fraction (92%) an acid tissue fraction (5%) and a skeletal fraction (3%). Identification of the primordial crystal population within membrane-bound visicles provides overwhelming evidence for the intracellular mode of calcification in Scleractinia. Moreover, it permits development of a novel concept of cellular regulation over these dynamic events. The membrane-bound vesicel is a miniature crystal fabrication station and a vehicle responsible for transportation of seed crystals and an organic matrix material to sites of discharge from the cell. The vesicle membrane becomes a probable locus of active transport and enzymatic activity as well as a physical barrier to be penetrated for release of vesicle contents into the extracellular milieu. Contact between the vesicle membrane and the plasmalemma would result in exocytosis and the onset of skeletogenesis. Principles governing crystal growth would prevail from then on. The released crystal becomes a nucleation catalyst and the organic matrix, a supply of ionic calcium for self-limiting crystallization. Crystals are produced by the organism spontaneously and continuously from shortly after larval attachment throughout the life of the polyp. Therefore, these membrane-bound vesicles signal the dynamic process by which initiation, differentiation, growth and limitation of the coral skeleton is regulated.read more
Citations
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Journal ArticleDOI
Geochemical perspectives on coral mineralization
TL;DR: Corals open an exceptional window into many phenomena of geological, geochemical, climatic, and paleontological interest as discussed by the authors, and they also represent a testing ground for basic ideas about mineralogy and geochemistry.
Journal ArticleDOI
Carbon and oxygen isotope fractionation in scleractinian corals: a review
TL;DR: In this paper, the carbon and oxygen isotopes are decoupled in scleractinian corals, and a model for fractionation of stable isotopes is proposed, based on data available on primary productivity, respiration and stable isotope chemistry.
Book ChapterDOI
Coral Calcification, Cells to Reefs
TL;DR: This chapter reviews the present knowledge and discusses the different theories on coral calcification, from the molecular to the reef level, and identifies key issues to be resolved in order to understand the intimate mechanisms of calcification of corals.
Journal ArticleDOI
Diurnal lipid and mucus production in the staghorn coral Acropora acuminata
TL;DR: Lipid and mucus synthesis is discussed in relation to the carbon budget of A. acuminata, in which mucus represented a loss of 40% net C fixation, and 14C was primarily associated with wax esters which were always present in the mucus-lipid.
Journal ArticleDOI
Coral growth rates and environmental control of density banding
TL;DR: Geographical patterns of coral density banding based on the literature are discussed and a model is proposed relating the interplay of light availability and water temperature to the production of high and low density skeletal bands.
References
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Journal ArticleDOI
Vesicles associated with calcification in the matrix of epiphyseal cartilage
TL;DR: It is suggested that matrix vesicles are derived from cells and that they may play a role in initiating calcification at the epiphysis.
Journal ArticleDOI
The physiology of skeleton formation in corals. i. a method for measuring the rate of calcium deposition by corals under different conditions
TL;DR: The calcification rate of reef corals grown in darkness for prolonged periods of time to remove the zooxanthellae is considerably reduced and seems independent of the light intensity.
Journal ArticleDOI
Fine structure and histochemistry of "calcifying globules" in epiphyseal cartilage.
TL;DR: The hypothesis that some globules derive from degenerating chondrocytes and others from the processes of normal chond rocytes are advanced, which would imply that the cartilage matrix in which calcium salts are deposited has been studied in the tibial epiphyses and in the costo-chondral junctions of 30-day-old guinea pigs.
Journal ArticleDOI
An electron microscopic study of initial intramembranous osteogenesis
TL;DR: Calvariae of fetal mice were investigated with electron microscopy in order to demonstrate initial stages of immature, membrane bone calcification, and the organic substructure of the bone nodules was revealed.
Journal ArticleDOI
Phosphates as crystal poisons of calcification
TL;DR: This theory that some metabolites which contain phosphate groups can act in the body as crystal poisons and so influence the deposition of calcium salts in skeletal structures is explained and the evidence for it reviewed.
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The physiology of skeleton formation in corals. i. a method for measuring the rate of calcium deposition by corals under different conditions
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