Accession Number : ADA318020

Title :   Chemosensory Stimulation of Molluscan Settlement and Metamorphosis.

Descriptive Note : Final rept.,

Corporate Author : HAWAII UNIV HONOLULU

Personal Author(s) : Hadfield, Michael G.

PDF Url : ADA318020

Report Date : 16 NOV 1996

Pagination or Media Count : 6

Abstract : A Settlement and metamorphosis of invertebrate larvae are key points in establishing and maintaining marine communities (including those on the bottoms of ships and piers). This research employed physiological and molecular methods to clarly (1) the basis in development of a model organism (the sea slug Phestilla sibogae) for establishing the capacity of larvae to metamorphose, (2) the receptor mechanisms for the larva's ability t6 detect settlement-stimulating chemical cues in the environment, (3) the genetic mechanisms in metamorphosis, and (4) the class of receptor molecules employed in chemoicception of the metamorphic cue. The recept& cells are included in a cilia-based organ on the head, and their specific vital staining with a vital stain allows photo-activation of metamorphosis. Metamorphic competence arises without last-minute genetic transcription or translation and probably involves morphogenesis and/or protein phosphorylation. Competent larvae survive without active cell division or genetic transcription or translation, and larvae can complete metamorphosis with all of these activities blocked. Chemical stimulation of metamorphosis causes changes in electrical activity in the brain, and the receptor for the metamorphic inducer probably is in the class of ligand-gated ion channels which transmit nervous signals at the synapse. Primary chemoreceptor cells on the cephalic tentacles of adult P. sibogae detect products from their prey corals and from polar amino acids. Current research builds on these findings.

Descriptors :   *STIMULATION(PHYSIOLOGY), *INVERTEBRATES, *LARVAE, *MOLLUSCA, *METAMORPHOSIS, POLAR REGIONS, SHIPS, BRAIN, CAPACITY(QUANTITY), CHEMICALS, MOLECULES, PROTEINS, ELECTRICAL PROPERTIES, SIGNALS, NERVOUS SYSTEM, PHYSIOLOGY, PIERS, CELL DIVISION, SYNAPSE, BOTTOM, INDUCTANCE, GENETICS, SENSE ORGANS, AMINO ACIDS, PHOSPHORYLATION, MORPHOGENESIS, METAMORPHIC GEOLOGY.

Subject Categories : Biology
      Medicine and Medical Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE