The Biological Bulletin, Vol 183, Issue 1 78-83, Copyright © 1992 by Marine Biological Laboratory

DEVELOPMENT AND REPRODUCTION

Localization of Laminin in the Subepidermal Basal Lamina of the Planarian Dugesia japonica

I. Hori
Department of Biology, Kanazawa Medical University, Uchinada, Ishikawa 920-02, Japan

The planarian subepidermal basal lamina consists of three structural elements: namely, an electronlucent zone, a limiting layer, and a microfibrillar layer. Ultrastructural observations following ruthenium red staining were in agreement with previously published reports. The staining clearly revealed positive material on the limiting layer and the individual microfibrils. The limiting layer was continuous and separated the electronlucent zone from the microfibrillar layer. The distribution of laminin, a noncollagenous basal lamina glycoprotein, was determined for the planarian basal lamina using various methods of immunocytochemistry. The reactive substance appeared only on the limiting layer and in the electronlucent zone along the limiting layer. The reactive products on the limiting layer appeared discontinuous. They were also present in the regenerated basal lamina, though the reactivity was a little weaker than in that of intact animals. Localization of laminin in the planarian subepidermal basal lamina is discussed in comparison with that of the basal lamina of vertebrates.