Studies on Water in Barnacle Muscle Fibres 1. The Dry Weight Components of Fresh Fibres

Abstract

The dry weight components comprise 25% of the total weight of fresh muscle fibres of the giant barnacle Balanus nubilis. Half of the solids are water insoluble; 6% of this material is fat, and the rest is mostly myofilament protein. Less than 3% of the dry weight consists of inorganic ions, and these account for only a quarter of the osmotic activity in the fibre water. Seventy per cent of the osmotic activity is due to nitrogenous solutes which comprise 18% of the dry weight. Glycine predominates, followed by TMAO+betaine, proline, glutamine+asparagine, arginine, and taurine. About 13% of the dry weight is soluble protein and not more than 10% is an unidentified soluble substance of high molecular weight. Thus, Balanus conforms with other marine invertebrates in the high content of osmotically active nitrogenous solutes in its myoplasm.