Effect of Carbonic Anhydrase Inhibitors on Shell Development and Growth of Balanus improvisus Darwin

Abstract

CARBONIC CARBONIC anhydrase, associated with respiration in some invertebrate and vertebrate animals, has been found in the shell-forming tissues of many mollusks (Freeman and Wilbur, 1948). More recently (Wilbur and Jodrey, 1955) it has been demonstrated that the enzyme is directly associated with shell deposition and that inhibition of carbonic anhydrase reduces the rate of calcium carbonate deposition both in whole oysters and in mantle-shell preparations. The calcareous shell plates of the acorn barnacles are similar to mollusk shells, in that much of the crystalline material deposited in the organic matrix is calcium carbonate. The enzyme systems associated with shell development and growth in barnacles are not known, and, although carbonic anhydrase has been reported from a wide variety of invertebrates (Brinkman, 1933, Ferguson, Lewis, and Smith, 1937), acorn barnacles have not been among the animals included in the studies. Darwin (1854) postulated that the calcareous plates of the Balanidae are formed by the apposition of the mantle against the older portions of the shell, but few additional studies have been made on shell development. The present study has had two major objectives: (1) to determine whether or not carbonic anhydrase is present in the shell-forming mantle and internal body tissues of Balanus improvisus Darwin and (2) to study the effects of carbonic anhydrase inhibitors on shell development, shell growth, and molting.