Purification of a novel antibacterial and haemagglutinating protein from the purple gland of the sea hare, Aplysia dactylomela rang, 1828

Toxicon. 2000 Oct;38(10):1415-27. doi: 10.1016/s0041-0101(99)00234-2.


Physicochemical characterisation and antibacterial and haemagglutinating properties of a new protein isolated from purple fluid of the Aplysia dactylomela are reported. The purification procedure consisted basically of ammonium sulphate fractionation, ion exchange, exclusion molecular and hydrophobic interaction chromatography. The highly purified protein, designated dactylomelin-P, is a single chain protein of 60,000 Da by SDS-polyacrylamide gel electrophoresis and 56,200 Da by gel filtration on calibrated Superose column at pH 7.5 and contains less than 0.05% of its weight in neutral carbohydrates. Dactylomelin-P has two biological activities, antibacterial and haemagglutinating. The antibacterial action is bacteriostatic but not bactericidal. The haemagglutinating activity is preferentially against rabbit erythrocytes. The glycoprotein fetuin was able to abolish the haemagglutinating activity but not the antibacterial one even when used at concentrations 10 fold higher. This is the first time that a chimeroprotein is described in the purple fluid of sea hares, which may be involved in the chemical defence mechanism of these organisms.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / isolation & purification*
  • Anti-Bacterial Agents / pharmacology
  • Aplysia*
  • Chromatography, High Pressure Liquid
  • Chromatography, Ion Exchange
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / drug effects
  • Escherichia coli / growth & development
  • Exocrine Glands / chemistry*
  • Hemagglutination / drug effects
  • Hemagglutination / physiology
  • Hemagglutinins / isolation & purification*
  • Hemagglutinins / pharmacology
  • Lectins
  • Microbial Sensitivity Tests
  • Molecular Weight
  • Rabbits
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / growth & development


  • Anti-Bacterial Agents
  • Hemagglutinins
  • Lectins
  • dactylomelin-P protein, Aplysia dactylomela