Echinoderms

To reproduce, echinoderms release sperm and eggs into water, where they fuse to form zygotes. Tarvae swim in the plankton for a short time, then settle to the bottom and take on typical echinoderm features. Most echinoderms can also reproduce asexually. If part of the animal breaks off, a piece may grow into a complete, new organism. All are capable of regenerating missing limbs, spines, and in some cases, intestines. 

Seaweed is the favorite food of the purple sea urchin (Arbacia punctulata), whose body is covered in 1-inch (2.5-cm) purple spines. During low tide, sea urchins use their tough spines to carve out holes in the rocks. Once inside their caves, they are protected from desiccation during low tide as 

Sand dollars are so flat that at first look they do not resemble their echinoderm relatives. The plates of their skeletons are fused and fixed, and the external surfaces are covered with tiny spines that look like fuzz or a short coat of hair. Sand dollars use their spines to burrow into sand. Once buried, the spines collect small food particles that fall among the spines and transfer them to the mouth. As shown in the upper color insert on page C-7, the common sand dollar (Echinarachnius parma) may be brown with purple or red tints. A five-petal pattern on the sand dollar s dorsal side corresponds to the five legs of a starfish. Holes near the tips of the petals allow the animal to extend tube feet, which are used for respiration. Most specimens measure about 3 inches (7.5 cm) in width. 

Sea cucumbers are a group of tubular echinoderms that he on their sides with their mouth at one end of the tube and anus at the other end. Around the mouth, several tube feet are modified to form tentacles. Some species use these to catch bits of food suspended in water or to pick up food-laden sediment. The respiratory structures of these animals are located alongside the digestive tract. 

The number and arrangement of tube feet on a sea cucumber vary, depending on the species. Usually found clinging to intertidal rocks, the orange-footed sea cucumber (Cucumaria fron-dosa) has tube feet arranged in five distinct bands along the length of its body. However, only the ones on the ventral side 

With the exception of two sea urchin samples collected from Puerto Rico, most chromium residues reported in echinoderms have been less than l.Omg/kg DW. The elevated levels of 24.0 and 43.0mg/kg FW of whole organism in Puerto Rican sea urchins are exceptions, which were not reflected in sea cucumber muscle from the same vicinity, and thus should be viewed with caution. Echinoderms from the United Kingdom and environments were comparatively low in chromium concentrations were less than 0.46 mg Cr/kg DW whole organism. Embryos of a sea urchin (Anthocidaris sp.) developed normally in solutions containing 3.2. 2 mg Cr/L, but failed to develop at 8.4-10.0 mg Cr/L. Larvae of another species of sea urchin (Hemicentrotus sp.) were more sensitive, showing abnormal development or dying within 24 h at concenttations of 1.0 mg Cr/L. Hexavalent chromium at 6.0 mg/L was associated with abnormal development in embryos of Anthocidaris crassispina. 

Trivalent chromium is relatively innocuous to the gray mullet (Chelon labrosus). Mullet held for 60 days in aquaria with sediments containing 46.0 mg Cr+ /kg DW and 

Male domestic chickens fed diets containing up to 100.0 mg Cr+ /kg ration for 32 days 

Chromium is the most common skin sensitizer known to human males. Up to 26% of all males tested and 10% of females were sensitive to potassium dichromate patch tests. The highest frequency of chromium-sensitive individuals was found in Brazil, Belgium, and North America, especially 

Detroit and New Orleans. Frequency of chromium dermatitis was highest in constmc-tion workers using cement. Other occupational exposures associated with chromium sensitivity include chromium plating, tanning of leather, application of anticorrosive agents, and printing. Oral ingestion of chromium com-poimds can sometimes lead to skin reactions in sensitive people. Hexavalent chromium com-poimds are more potent inducers and elicitors of skin sensitivity than trivalent chromium compoimds, probably because Cr+ com-poimds can penetrate die skin more readily than Cr+ compoimds. 

The three-tier assembly documented for mother-of-pearl can be extended to the nanoscale architectures of other mineralized organisms. The sponge skeletal organization of echinoderms, for example, is composed of calcific nanobricks of one, single Mg-bearing calcite crystal. Three species of echinoderms and one shell of a sea urchin were analyzed using FESEM, field emission TEM (FETEM), SAED 

1 Biomimetic Synthesis of Metal Oxides Using Echinoderms as Inspiration 

Interaction between the nanobricks and biopolymers producing the emergence of molecular storage and (E) polycrystalline arrangement. Reproduced with permission from Ref [31] 2006, Wiley-VCH Verlag GmbH Co. KCaA. 

A mixture of manganese chloride tetrahydrate (MnCl2-4H20) and PAA immediately formed a clear orange liquid that became turbid after several hours of 

A similar synthesis incorporating cobalt chloride hexahydrate (C0CI2 6H2O) and PEI produced a reddish-yeUow composite solution that was shown to be composed of hexagonal nanoflakes that were less than 100nm in size. Both, FETEM and 

---

Animal aquaculture is concentrated on finfish, moUuscs, and cmstaceans. Sponges, echinoderms, tunicates, turtles, frogs, and alligators are being cultured, but production is insignificant in comparison with the three principal groups. Common and scientific names of many of the species of the finfish, moUuscs, and cmstaceans currently under culture are presented in Table 2. Included are examples of bait, recreational, and food animals. 

Steroids with 0-heterocyclic fragments (pyrans and 0-macroheterocycles) as bioactive metabolites from echinoderms andporifera 97G771. 

Ordovician 500 Myr Diversification of echinoderms, other invertebrate phyla, jawless fishes. Mass extinction at end of period (ca. 85To of all species disappear)... 

Coelenterates and Echinoderms. In the phylla Coelenterata and Echinodermata approximately 90 species have been investigated for toxicity (see Tables II and IH). Only 20 or so have been extensively studied (e.g., sea anemones, sea cucumber, and jellyfish). Even so, while relatively complete studies have been made on isolation, characterization, and elucidation of mechanisms of action, in no one species have all of the toxins present been identified. Thousands of species have not been subjected to even the most cursory examination. 

Table III. Partial List of Echinoderms from which Toxic Substances Have Been Isolated...

Coelenterates and Echinoderms. Coelenterate and echinoderm toxins range from small molecular weight amines, to sterols, to large complex carbohydrate chains, to proteins of over 100,000 daltons. Molecular size sometimes reflects taxonomy, e.g., sea anemones (Actiniaria) all possess toxic polypeptides varying in size from 3,000 to 10,000 daltons while jellyfish contain toxic proteins (ca. 100,000 daltons). Carotenoids have been isolated from Asterias species (starfish), Echinoidea (sea urchins), and Anthozoans such as Actiniaria (sea anemones) and the corals. These are sometimes complexed with sterols (J5). 

Goad (40) and others have extensively reviewed coelenterate and echinoderm sterols including the saponins found in starfish and sea cucumbers. Cholesterol is a common sterol in most families, except for gorgonians and zoanthids some soft corals contain polyhydroxylated sterols. The amount of variation associated with phylogeny is illustrate in the echinoderms by the fact that crinoids, ophuiroids, and echinoids contain A 5 sterols while holothuriodeans and asteroids contain A 7 sterols. Some classes contain uniquely structured sterols. 

Many of the toxins obtained from coelenterates and echinoderms, because of their hemolytic or cytotoxic actions, are assumed to have a general disruptive action on cell membranes. However, since many of these toxins are capable of forming pores or channels in the plasma membrane of cells, their cytolytic actions may be a result of this highly selective action. On the other hand, the saponins from starfish and sea cucumbers have a direct lytic action as a result of their detergent action on the integrity of cells. 

Although they are pigments, quinones make only small contributions to the colors of tissues and organisms that produce them. Quinones play an important role in the coloration of some fungi, lichens, insects (Coccidae), and echinoderms, but they rarely contribute to the external colors of higher plants. 

Hatten ME 1999 Central nervous system neuronal migration. Annu Rev Neurosci 22 511—539 Horstadius S 1973 Experimental embryology of echinoderms. Clarendon Press, Oxford Horvitz HR, Herskowitz 11992 Mechanisms of asymmetric cell division two Bs or not two Bs, that is the question. Cell 68 237-255... 

The effects of decadienal (24) as well as of diatom extracts are not restricted to the reduction of copepod success. Low, micromolar concentrations of this compound also inhibits fertilization, embryogenesis, and hatching success in polychaetes and echinoderms. Crude diatom extracts as well as purified aldehydes inhibited these processes in a dose-dependent manner [80]. 

Dickson, J.A.D. (2002). Fossil echinoderms as monitor of the Mg/Ca ratio of phanerozoic oceans. 

Riley, J.P. and D.A. Segar. 1970. The distribution of the major and some minor elements in marine animals. I. Echinoderms and coelenterates. Jour. Mar. Biol. Assoc. UK. 50 721-730. 

Papadopoulu, C., G.D. Kanias, and E.M. Kassimati. 1976. Stable elements of radioecological importance in certain echinoderm species. Mar. Pollut. Bull. 7 143-144. 

Copper compounds are used routinely and widely to control freshwater snails that serve as intermediate vectors of schistosomiasis and other diseases that afflict humans (Hasler 1949 NAS 1977 Rowe and Prince 1983 Winger etal. 1984 Al-Sabri etal. 1993). These compounds include copper sulfate, copper pentachlorophenate, copper carbonate, copper-tartaric acid, Paris green (copper arsenite-acetate), copper oxide, copper chloride, copper acetyl acetonate, copper dimethyl dithiocar-bamate, copper ricinoleate, and copper rosinate (Cheng 1979). Also, many species of oyster enemies are controlled by copper sulfate dips. All tested species of marine gastropods, tunicates, echinoderms, and crabs that had been dipped for 5 seconds in a saturated solution of copper sulfate died if held in air for as little as a few seconds to 8 h mussels, however, were resistant (MacKenzie 1961). 

---