Protein extracts from some marine animals which promote barnacle settlement: possible relationship between a protein component of arthropod cuticle and actin

Abstract 1. 1. Physicochemical properties of protein-containing settlement factor extracts of Carcinus maenas carapace, Pecten maximus adductor muscle and Blennius pholis body tissues were examined. 2. 2. Similarities between the molecular weights and electrophoretic patterns of the protein components were observed. 3. 3. Crab, blenny and adductor muscle extracts were stable to boiling in the same way as barnacle settlement extracts previously studied. 4. 4. Statistical analysis of published amino acid compositions of several structural proteins showed a close homology with actin and with crab cuticle and barnacle extracts. 5. 5. Extracts from P. maximus and B. pholis containing mainly actin and tropomyosin, promoted the settlement of barnacle cyprids.