Produced by Vibrio cholerae, cholera toxin (CT) is a multimeric enterotoxin that transfers ADP-ribose to a G protein, locking adenylate cyclase in an 'on' position.
Starfish, sand dollars, and sea urchins all belong to a group (phylum) of invertebrates known as echinoderms. The word echinoderm means spiny skin, which describes most of the organisms in this phylum.tarfish, sand dollars, and sea urchins all belong to a group (phylum) of invertebrates known as echinoderms. The word echinoderm means spiny skin, which describes most of the organisms in this phylum.
The adults are recognizable by their (usually five-point) radial symmetry, and include such well-known animals as starfish, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or stone lilies. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone.chinoderms have a mesodermal skeleton composed of calcareous plates or ossicles. Each one of these, even the articulating spine of a sea urchin, is composed mineralogically of a crystal of calcite. If solid, these would form a heavy skeleton, so they have a sponge-like porous structure known as stereom.