海綿動物の細胞内浸透圧調節における遊離アミノ酸とベタイン類の役割〔英文〕

概要

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Six species of marine sponges belonging to the class Demospongiae were analyzed for free amino acids and betaines, and changes in their concentrations in two species of intertidal sponges exposed to hypo-and hyperosmotic stresses were investigated. The concentration profile of individual free amino acids and betaines in those sponges was characterized by a high level of glycine. Especially, two intertidal species, Halichondria okadai and H. japonica, were very rich in this amino acid. The amount of cyclic betaines such as homarine and trigonelline more or less exceeded that of ω-betaines such as glycinebetaine, β-alaninebetaine, and ϒ-butyrobetaine. The trigonelline level in H. japonica was particularly high. Although most of free amino acids and betaines in the two intertidal sponges fluctuated in response to salinity changes, the major portion of the total change in those components was at-tributable to glycine. Under high salinity conditions, trigonelline in H. japonica also played a significant role in intracellular osmoregulation.