Stony corals

The sub-phyllum Anthozoa (6,500 species) contains the classes Alcyonaria (soft corals, sea fans, sea pens, sea pansies), Zoantharia (sea anemones and true corals), and Ceriantipatharia. The Scleroactinia (Madreporaria-true or stony corals) build the massive coral reefs and atolls which occur in tropical waters. According to Hashimoto (75), toxicity to humans is mainly found in the fire or stinging corals (Millepora sp.) and, to a lesser extent, in the stony corals (Goniopora sp.). 

Both sea anemones (order Actinaria) and stony corals (order Scleractinia) belong to the class Zoantharia and sub-phylum Anthozoa and therefore it is not surprising that toxic polypeptides of 12,000 and 30,000 daltons have also been isolate from Goniopora corals. 

Several other fluorescent proteins have been isolated from a variety of species. We will briefly discuss the variants with the most optimal spectroscopic properties. A true orange fluorescent protein was isolated from the stony coral Fungia concinna, with good absorbance and a quantum yield of 0.45. Targeted mutagenesis was used to monomerize the protein, yielding mKO with an absorbance of 51,600 M-1 cm 1 and a quantum yield of 0.74 [84, 85], The crystal... 

Kogure, T., Karasawa, S., Araki, T., Saito, K., Kinjo, M., and Miyawaki, A. 2006. A fluorescent variant of a protein from the stony coral Montipora facilitates dual-color singlelaser fluorescence cross-correlation spectroscopy. Nature Biotechnol. 24 577-81. 

Iwagawa T, Miyazaki M, Okamura H, Nakatani M, Doe M, Takemura K (2003) Three Novel Bis(indole) Alkaloids from a Stony Coral, Tubastracea sp. Tetrahedron Lett 44 2533... 

Another large group of brominated tryptophan-derived marine alkaloids are the aplysinopsins and several new examples have been reported. The sponge Hyrtios erecta has furnished 20 and 21[26], while a New Zealand asddian is the source of kottamides A-E, for example A (22) [27] and E (23) [28], The stony coral Tubastraea sp. contains the structurally complex and unprecedented bisindole tubastrindole A (24) [29]. 

Shashar, N., Cohen, Y., Loya, Y., and Sar, N. (1994a). Nitrogen-Fixation (Acetylene-Reduction) in Stony Corals - Evidence for Coral-Bacteria Interactions. Mar. Ecol. Prog. Ser. 111(3), 259—264. 

Bak, R.P.W., 1974. Available light and other factors influencing growth of stony corals through the year in Curacao. Proc. Second Internat. Coral Reef Symp., Brisbane. Great Barrier Reef Committee, pp. 229—233. 

Fukami, H. Chen, C.A. Budd, A.F. Collins, A. Wallace, C. Chuang, Y.-Y. Chen, C. Dai, C.-F. Iwao, K. Sheppard, C. Knowlton, N. (2008). Mitochondrial and Nuclear Genes Suggest that Stony Corals are Monophyletic but most Families of Stony Corals are not (Order Scleractinia, Class Anthozoa, Phylum Cnidaria), PLoS One, Vol. 3, No. 9, e3222. 

Tubastraine (274) was isolated from the stony coral Tubastraea micrantha. Its structure was established with IR, MS, one- and two-dimensional H and 13c NMR, and by its synthesis from 272 [610]. 

Corals may grow as solitary or colonial forms. The process of calcification in stony corals (sclerac-tinians) occurs in the lower portion of the polyp, producing a cup-like stmcture, the calyx, in which the pol3fp (typically 1-3 nun in diameter) sits. Stmctural elements of calyx comprise the surrounding walls (theca), the floor (basal plate), and, extending upwards from the basal plate a series of thin, radial elements (sclerosepta). 

Stony corals make their exoskeletons from dissolved Ca and C03 ions. This process is aided by the fact that the C03 concentration is supersaturated in most parts of the ocean. However, well-documented increases in the amount of CO2 in the atmosphere threaten to upset the aqueous chemistry that stony corals depend on. As atmospheric CO2 levels increase, the amount of CO2 dissolved in the ocean also... 

The availability of carbonate ions plays an important role in shell formation for a number of marine organisms, including stony corals ( FIQURE 17.18). These organisms, which are referred to as marine calcifters and play an important role in the food chains of nearly all oceanic ecosystems, depend on dissolved Ca and C03 ions to form their shells and exoskeletons. The relatively low solubility-product constant of CaC03,... 

A. FIGURE 17.18 Marine calcifiers. Many sea-dwelling organisms use CaCOs for their shells and exoskeletons. Examples inolude stony coral, crustaceans, some phytoplankton, and echinoderms, such as sea urchins and starfish. 

Water, the most common and most important solvent on Earth, occupies its position of importance because of its abundance and its exceptional ability to dissolve a wide variety of substances. Coral reefs are a striking example of aqueous chemistry at work in nature. Coral reefs are built by tiny animals called stony corals, which secrete a hard calcium carbonate exoskeleton. 

Over time, the stony corals build up large networks of calcium carbonate upon which a reef is built. The size of such structures can be immense, as illustrated by the Great Barrier Reef. 

Stony corals make their exoskeletons from dissolved Ca and ions. This pro-... 

This lowers the pH of the ocean and leads to a decreaise in the C03 concentration. As a result it becomes more difficult for stony corals and other importemt oceem creatures to maintain their exoskeletons. We will take a closer look at the consequences of oceem acidification later in the chapter. 

Isol. from the sponge Mycale sp. and from the stony coral Tubastrea faulkneri. Cytotoxic. Yellowish gum. [al. -62.1 (c, 3.7 in CHCI3). 

Strontium is quite common in seawater. Some organisms use strontium sulfate as a skeletal material. Strontium is added to the water in aquariums, as the decorative stony corals need it. Strontium has no function in the human body. (It is the most abundant element in the human body without a known function there.) Nor is barium essential for Hfe indeed it is toxic. The symptoms of barium poisoning are colic, diarrhoea, vomiting and paralysis. The content of barium in food plants is as a rule low (part per million levels) but there is an exception Brazil nuts may contain as much as 1% barium. The metabolism is stimulated by barium, but to such a high degree that the heart begins to beat erratically (ventricular fibrillation). Barium salts are thus toxic to humans, but the use of barium sulfate as an X-ray contrast medium is accepted because of its very low solubility. 

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. 

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