Some observations on the Ca2+-binding phospholipid from scleractinian coral skeletons

Isa, Yeishin; Okazaki, Megumi

doi:10.1016/0305-0491(87)90045-9

Cited by 43 publications

(34 citation statements)

References 17 publications

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“…In addtion, heterotrophic feeding and algal photosynthesis influence fatty acid compositions in coral tissue, so that compositions can be variable (e.g., Harland et al, 1992). Previous reports of fatty acids in corals indicate that there is usually more C16:0 than C18:0 in coral tissue and skeletons (Meyers et al, 1974;Isa and Okazaki, 1987;Harland et al, 1993). These two compounds are also the major fatty acids in the corals we analyzed, although C18:0 was present in higher concentration than C16:0.…”

Section: Lipidsmentioning

confidence: 77%

“…Soluble polyanionic proteins, containing sulfated carbohydrate moieties, are thought to be directly responsible for both promoting and inhibiting CaCO 3 precipitation (Addadi et al, 1987;Dauphin, 2001). Lipids are minor organic constituents of coral skeletons (Isa and Okazaki, 1987;Stern et al, 1999). Lipids, including nalkanes, fatty acids, and cholest-5-en-3␤-ol (cholesterol), may participate in calcification; however, much less is known about their composition and their role in biomineralization compared to amino acids.…”

Section: Introductionmentioning

confidence: 99%

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Preservation of organic matter in mound-forming coral skeletons

Ingalls

Lee

Druffel

2003

Geochimica et Cosmochimica Acta

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Section: Lipidsmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Preservation of organic matter in mound-forming coral skeletons

Ingalls

Lee

Druffel

2003

Geochimica et Cosmochimica Acta

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“…This would be in line with the two-step mechanism proposed by Cuif & Dauphin (2005a,b) in which the biomineralization process starts with secretion of a proteoglycan matrix in which mineralization takes place. The matrix has been shown to contain structural proteins which play a catalytic role similar to that of carbonic anhydrase , has calcium binding properties (Isa & Okazaki 1987;Constantz &Wiener, 1988 andPuverel et al 2005) and acidic proteins regulating the biomineralization process and the mineralization process (Rahman & Oomori, 2009) may involve all of these. Confirmation for the presence of carbonic anhydrase on the surface of waterpiked corals comes from the experiment involving inhibition of calcification by acetazolamide (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Active calcification in scleratinian corals is a two stage process which involves secretion of a layer of organic matrix (reviewed by Allemand et al1998 andAllemand et al 2011) and calcium carbonate, crystallized in the form of aragonite, is deposited in the organic matrix with the involvement of structural proteins with a catalytic role similar to that of carbonic anhydrase , calcium binding compounds (Isa & Okazaki, 1987, Constantz & Wiener 1988and Puverel et al 2005 and proteins regulating the biomineralization process along with Mg 2+ which inhibits calcite formation (Rahman & Oomori, 2009). Aragonite deposition takes place from the extracellular calcifying fluid (ECF) or hydrogel-like medium (ECM) (Bryan &Hill, 1941 andCuif et al 2004a) onto the organic matrix framework on the surface of the skeleton.…”

mentioning

confidence: 99%

Preliminary results with a torsion microbalance indicate that carbon dioxide and exposed carbonic anhydrase in the organic matrix are the basis of calcification on the skeleton surface of living corals

Sandeman

2015

RBT

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Ocean acidification is altering the calcification of corals, but the mechanism is still unclear. To explore what controls calcification, small pieces from the edges of thin plates of Agaricia agaricites were suspended from a torsion microbalance into gently stirred, temperature controlled, seawater. Net calcification rates were monitored while light, temperature and pH were manipulated singly. The living coral pieces were sensitive to changes in conditions, especially light, and calcification was often suspended for one or two hours or overnight. The mean calcification rate increased from 0.06 in the dark to 0.10 mg.h -1 .cm -2 (T test, n=8, p<0.01) in low light (15 μmol.s -1 .m -2 ) and showed a positive linear relationship with temperature. With a reduction of mean pH from 8.2 to 7.6 the mean calcification rate in the light (65 μmol.s -1 .m -2 ) increased from 0.19 to 0.28 mg.h -1 .cm -2 (T test, n=8, p<0.05) indicating a dependency on carbon dioxide. After waterpiking and exposure of the skeletal surface/organic matrix to seawater, calcification showed an astonishing initial increase of more than an order of magnitude then decreased following a non-linear generalised Michaelis-Menten growth curve and reached a steady rate. Calcification rate of the freshly waterpiked coral was not influenced by light and was positively correlated with temperature. For a mean pH reduction from 8.1 to 7.6 the mean calcification rate increased from 0.18 to 0.32 mg.h -1 .cm -2 (T test, n=11, p<0.02) again indicating a dependency on carbon dioxide. Calcification ceased in the presence of the carbonic anhydrase inhibitor azolamide. Staining confirmed the presence of carbonic anhydrase, particularly on the ridges of septae. After immersion of waterpiked corals in seawater for 48 hours weight gain and loss became linear and positively correlated to temperature. When the mean pH was reduced from 8.2 to 7.5 the mean rate of weight gain decreased from 0.25 to 0.13 mg.h -1 .cm -2 (T test, n=6, p<0.05) indicating a dependence on carbonate. At a pH of 6.5 the skeleton lost weight at a rate of 1.8 mg.h -1 .cm -2 . The relationship between net calcification and pH (n=2) indicates that wt gain turns to loss at pH 7.4. These experiments confirm that calcification is a two-step process, involving secretion of a layer of organic matrix incorporating carbonic anhydrase to produce an active calcifying surface which uses carbon dioxide rather than carbonate. It is also unlikely that the calcifying surface is in direct contact with seawater. Inorganic deposition or dissolution of the skeleton in exposed dead areas of coral is a different phenomenon and is carbonate related. The wide range in results from this and other studies of calcification rate and carbon dioxide may be explainable in terms of the ratio of "live" to "dead" areas of coral. Rev. Biol. Trop. 60 (Suppl. 1): 109-126. Epub 2012 March 01.

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“…It has been reported that coral skeleton contains organic matter such as mucopolysaccharides (Goreau 1959), proteins (e.g., Allemand et al 1998), calcium-binding phospholipids (Isa and Okazaki 1987), and glycoproteins (Constantz and Weiner, 1988). Allemand et al (1998) demonstrated that inhibition of protein synthesis reduced Ca deposition rate simultaneously, suggesting that organic matrix biosynthesis, rather than calcium deposition, may be a limiting factor controlling the coral skeletogenesis.…”

Section: Enriched Period (D)mentioning

confidence: 99%

Imbalanced coral growth between organic tissue and carbonate skeleton caused by nutrient enrichment

Tanaka

Miyajima

Koike

et al. 2007

Limnology & Oceanography

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Effects of moderate nutrient enrichment (NO { 3 : ,5 mmol L 21 , PO 3{ 4 : ,0.3 mmol L 21 ) on two carbon (C) fixation rates (photosynthesis and calcification) of the zooxanthellate coral Acropora pulchra were investigated under laboratory conditions. The coral branches were incubated in the nutrient condition for three different periods (0, 5, 10 d) to observe changes in tissue biomass and zooxanthellate chlorophyll a (Chl a) concentration. Next, the incubated corals were simultaneously transferred to nutrient-depleted seawater containing 13 C-labeled dissolved inorganic carbon to assay net photosynthesis and calcification rates. Chl a concentration per unit surface area increased 2.6-fold for the 10-d enrichment, and net photosynthetic rates were also stimulated up to a similar level (2.8-fold). Tissue biomass of the host coral and zooxanthellae was approximately doubled during the period. On the other hand, calcification rates only increased 1.3-fold, suggesting that even moderate nutrient loading resulted in one-sided enhancement of the algal photosynthetic activity. The measured C fixation ratios of organic C : skeletal C were higher than the structural ratios, and the inconsistency became greater as Chl a concentration increased. The increased photosynthetic products could be excessively stored in the organic tissue and/or released into the ambient seawater.

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Some observations on the Ca2+-binding phospholipid from scleractinian coral skeletons

Cited by 43 publications

References 17 publications

Preservation of organic matter in mound-forming coral skeletons

Preservation of organic matter in mound-forming coral skeletons

Preliminary results with a torsion microbalance indicate that carbon dioxide and exposed carbonic anhydrase in the organic matrix are the basis of calcification on the skeleton surface of living corals

Imbalanced coral growth between organic tissue and carbonate skeleton caused by nutrient enrichment

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