The gill arch of the striped bass, Morone saxatilis. III. Morphology of the basal lamina as revealed by various ultrasonic microdissection procedures.

The ultrastructure of the surface epithelium and the associated basal lamina of the gill arches of the striped bass, Morone saxatilis, were investigated with the scanning electron microscope following complete or partial removal of the epithelium by ultrasonic microdissection. The microdissection procedures employed various combinations of the techniques of aldehyde fixation, treatment with borate, and extensive osmication followed by mild sonication. Generally, aldehyde fixation increases intercellular adhesion, excess osmication increases tissues brittleness, and borate treatment causes extensive tissue dissociation. However, the degree of epithelial removal following sonication of tissues treated with these various procedures varies considerably with specimen structure, shape, proximity to adjacent structures and freedom to vibrate during sonication. The basal lamina exhibits a smooth contour over most of the gill surface with the exception of the short gill rakers where it formed cones within the taste bud cores, and on the respiratory lamellae where it closely mimicked the underlying capillary network.