The chitin secreting system from deep sea hydrothermal vent worms

Summary— Deep-sea hydrothermal vent worms livé in tubes made of giant β-chitin crystallites (50 nm in diameter, several μm in length) embedded in a protein matrix. These chitin cyrstallites form a liquid-crystal-like structure differing from the wellknown cholesteric arrangement of classical chitin-protein systems. Furthermore, and in contrast with the latter systems, the vestimentiferan chitin-protein systems are produced by goatskin-shaped glands. Rod-shaped elements in the lumen of these glands were identified by DCTEM and Au-WGA labeling and freeze fracture as chitin crystallites. The main characteristics of these “chitin secreting glands” are described.