ABSTRACT
Nematocysts from the anemones Aiptasia pallida and Pachycerianthus torreyi were investigated. SDS-polyacrylamide electrophoresis of solubilized Aiptasia nematocysts revealed one major protein band (mol. wt 31,800) and several minor components. Coelectrophoresed whole venom contained numerous protein components, of which a major one appeared to be identical to the major nematocyst protein. Nematocyst capsules and everted threads from both species contained levels of glycine and proline-hydroxyproline characteristic of vertebrate collagens. Cysteine was present in significant amounts. Aiptasia whole venom contained high levels of glutamic acid and/or glutamine (71%) with no detectable cysteine or proline-hydroxyproline. The 31,800-dalton venom protein possessed only glycine (80%) and glutamyl and/or glutaminyl (20%) residues.
Subject(s)
Cnidaria/analysis , Cnidarian Venoms/isolation & purification , Proteins/isolation & purification , Sea Anemones/analysis , Amino Acids/analysis , Animals , Electrophoresis, Polyacrylamide Gel , Molecular WeightABSTRACT
Hydra that still contain partially digested food in their gastrovascular cavities, undergo a modified feeding response when they ingest additional prey. A localized constriction is formed just below the sites of tentacle attachment, preventing the loss of gastrovascular contents. This response involves the interaction of an ectodermal receptor system for glutathione and an endodermal receptor system for tyrosine.
