Biological protective substances in Marthasterias glacialis (Asteroidea) epidermal secretion

Marthasterias glacialis secretes a watery mucous liquid consisting of 14% carbohydrate and 86% protein. The mucous secretion possesses different biological active molecules responsible for lysozyme-like, protease and haemolytic activities. These substances could constitute a molecular barrier playing a protective role against the penetration by bacteria, fungi and parasites. The secretory apparatus consists of two unicellular glands, a large goblet cell and a granular cell, which open directly into the epidermis.