Proposed mechanism of enzyme transport between shipworms and their bacterial symbionts

Bacterial carbohydrate active enzymes (CAZymes) play an important role
in wood digestion in shipworms. The main site of lignocellulose
digestion within these wood-boring molluscs is the caecum, which
contains both endogenous lignocellulolytic enzymes and prokaryotic
enzymes produced by endosymbiotic bacteria resident within specialised
shipworm cells called bacteriocytes, located in the animal’s gills.
Until now, the mechanism by which bacterial enzymes reach the distant
caecum lumen has remained mysterious.