Alkaline phosphatase and carbonic anhydrase activity associated with arm regeneration in the seastarAsterias forbesi

A sharp increase in alkaline phosphatase (AP) activity occurred 7 d after arm autotomy inAsterias forbesi. This activity remained elevated at 20 d post-autotomy, during which time active ossicle-calcification was occurring. By 60 d post-autotomy, AP activity had returned to the level of non-regenerating individuals. Conversely, carbonic anhydrase (CA) activity exhibited no initial change in response to arm autotomy. By Day 60 a 50% increase in CA activity was observed. AP is localized in the outer membranes and associated microvilli of the coelomic epithelium and is not associated directly with the tissues involved in calcification. CA activity was highest in the tissues containing the ossicles, but was also present in the non-calcifying tube feet. These data suggest that inA. forbesi AP is involved in cell division and differentiation associated with wound-healing and the initiation of the regeneration process, and that CA may facilitate the ongoing maturation process, of newly formed ossicles.