Coral organic matrix

A review of analyses of the composition of mucus indicated that protein makes up 4—49% of the coral organism with total N making up 0.04—5.2% of mucus (Brown and BytheU, 2005). The primary constituents of the mucus matrix are glycoproteins or mucins. In a recent model of the mucus layer, organic exudates and organic N are released from the coral surface and go on to support a dynamic microbial community within the mucopolysaccharide layer around the coral (Rohwer and KeUey, 2004). 

AUemand, D., Tambutte, E., Girard, J. P., and Jaubert, J. (1988). Organic matrix synthesis in the scleratinian coral Stylophom pistiUata Role in biomineralization and potential target of the organotin tributyltin. J. Exp. Biol. 201, 2001-2009. 

Muscatine, L., Goiran, C., Land, L., Jaubert, J., Cuif, J. P., and AUemand, D. (2005). Stable isotopes (delta C-13 and delta N-15) of organic matrix from coral skeleton. Proc. Natl. Acad. Sci. USA. 102(5), 1525-1530. 

Anatomical aspects. The skeletons of corals are formed of crystals of aragonite in an organic matrix. Calcification begins when the free-swimming larva attaches to the substratum. The larva then metamorphoses into a polyp which continues to deposit extracellularly CaCOs and organic matrix through the secretory activity of the calicoblastic epithelium. The epithelium is a layer of cells at the base of the polyp adjoining the skeletal area at which deposition takes place. 

Enzymes. An obvious additional factor in biomineralization is enzyme activity. Enzymes are involved in the movements of ions by membrane pumps, the synthesis of organic matrix and sclerotized skeletal material, photosynthesis of coral zooxanthellae, and reactions involving COj. The best studied of these is carbonic anhydrase which catalyses the reactions... 

Abstract This contribution summarizes the considerations that are of major importance in inorganic mineral formation before we look at specific biological minerals. Some factors which have to be taken into account (other than those that are well-known from inorganic (abiological) precipitations) are the nature of the biological organic matrix the restricted volume, outside or inside the cytoplasm, which can cause differences in impurity content (Mg) crystal morphology and isotopic fractionation. Cases such as those of corals, foraminifera and coccoliths are taken as examples. 

Now corals have a toolkit of 36 such proteins. .. J. L. Drake et al. Proteomic analysis of skeletal organic matrix from the stony coral Stylophora pistillata. 2013. Proc Natl Acad Sci. 110(10), p. 3788. DOI 10.1073/pnas.l301419110. 

Puverel, S., Tambutte, E., Pereira-Mouries, L., Zoccola, D., Allemand, D., and Tambutte, S. (2005) Soluble organic matrix of two scleratinian corals partial and comparative analysis. Comp. Biochem. Physiol, 141B, 480-487. 

Mother of pearl, also composed of calciirm carbonate and an organic matrix, has been proposed as a substitute for bone. Mother of peari powder implanted in a bone defect has shown behavior similar to that of a coral [LOP 98]. 

Most MAAs are intracellular, although MAAs can be translocated to external surfaces of cells and organisms because MAAs are found in significant concentrations in the extracellular sheath matrix of some cyanobacteria and in coral mucus.134 163 176 Scytonemin is not found intracellularly. It is located extracellularly in association with the glycan sheath but is not a structural component of the sheath layer.194 197 Scytonemin concentrations are not uniform within the sheath layer, and variations are related to the age of the sheath. In Scytonema myochrous, higher concentrations of scytonemin occur near the base of filaments where the sheath is older and thicker, while at newly formed apical cells, the sheath is usually absent or devoid of pigment.198... 

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