Ultrastructural localization of tyrosinase in the tardigrade cuticle.

Tyrosinase activity has been demonstrated ultra-structurally in the cuticle of the eutardigrade Macrobiotus hufelandi. The enzyme could be localized in the outer layer (=epicuticle) of the integument. A weak deposition of reaction product was also seen in the cytoplasm of storage cells, free floating in the haemolymph.