Effect of Tetracycline on Crystal Growth

IN a previous investigation 1 , it was shown that when the larvæ of the sand-dollar E. parma were reared in sea-water containing low concentrations of tetracycline, the fluoro-phore was incorporated into the growing skeleton. At higher concentrations, reduction or failure of the formation of skeletal elements resulted. Further, the addition of calcium to the sea-water–tetracycline mixtures in excess of the theoretical amount with which tetracycline could combine, failed to prevent inhibition of mineralization. Several additional investigations carried out by my colleagues and me have demonstrated that administration of tetracycline to organisms producing skeletal elements results in hypomineralization of bones 2 and teeth 3 . In an attempt to elucidate the mechanism of hypomineralization in greater detail, we selected as a test object the regenerating shell of the marine mollusc Pinna , in which the regenerating portion of the shell consists of large calcite crystals.