AbstractsBiology & Animal Science

Typescript. Thesis – University of Hawaii, 1964. Bibliography: leaves 124-126. xiii, 126 leaves ill. (part mounted, part col.), tables A potent venom was isolated from the heads of globiferous pedicellariae of the sea urchin, Tripneustes gratilla (Linnaeus) by homogenization with an aqueous salt solution. The homogenate contained an active, non-dialysable, thermolabile, biuret positive material which exhibited strong ultraviolet absorption at 278 mu., whereas no active, dialysable components were present. Some purification was achieved by ammonium sulfate fractional precipitation and carbon adsorption. These procedures eliminated inactive contaminants and increased the ratio of protein to non-protein constituents by a factor of three. The active material was further separated into seven distinct bands by polyacrylamide gel electrophoresis, but no assignment of activity could be made to these components. A preliminary pharmacological characterization of the venom was obtained on the basis of the response of whole animals and isolated organ and tissue systems. Animals such as the mouse and rabbit were highly susceptible to the venom, and death was preceded by respiratory distress, excitability, and terminal tonic convulsions. The venom produced a marked drop in arterial blood pressure and a disorientation of electrocardiogram in anesthetized rabbits, and caused an auricular-ventricular block in isolated toad and guinea pig hearts. The existence in the venom of acetylcholine, histamine, or serotonin, or substances possessing similar actions was precluded by experiments on the isolated rat and guinea pig gut, and the isolated protractor muscle of the lantern of sea urchins. The venom had neither a neuro-muscular blocking action nor a direct effect on conduction in the isolated nerve. Microscopic examination of the heads of globiferous pedicellariae showed them to be composed of three adjacent jaws each containing a supporting calcareous element or valve with a terminal hook, a bilobed muscular sac with terminations near-the base of the hook, three functional muscle groups for opening and closing of the jaws, and bending the heads on stalks, and an enveloping, cuboidal epithelium. No glandular epithelium or holocrine-type secretory cells were apparent within the muscular sac, although the lumen was filled with a very course, granular material.