Studies on the in vitro formation of periostracum inHelisoma duryi: the influence of brain

Abstract

Excised mantle tissue produces periostracum when placed in organ culture. Mantle collars taken from animals exhibiting a fast rate of shell deposition in vivo produce more periostracum than mantle collars from slow growing animals. The addition of a brain from a fast growing animal increased periostracum production by a mantle collar from a slow growing animal. This effect was enhanced by removing the cerebral ganglia lateral lobes. This suggests that a factor(s) is present in the brain of fast growing animals which enhances periostracum formation in vitro. The lateral lobes appear to inhibit this activity. Radiolabel incorporation studies suggest that the periostracum produced by fast growing animals has a higher glycine content than that produced by slow growing animals.