Ultrastructure and glycoconjugate histochemistry of the lens capsule during lens regeneration from the iris in the Newt.

The lens capsule of the regenerating lens develops from the basal lamina of the iris epithelium. As the lens differentiates and grows in size, the lens capsule increases in thickness by the formation of successive layers of basal laminar material resulting in a structure composed of increasing numbers of parallel lamellae. This initial arrangement may be lost and a more homogeneous composition of fine granules and filaments may characterize some parts of the capsule in older lenses. The developing lens capsule stains with the PAS and PAPD methods but not with the PAPS, AB and HID methods. Therefore, it appears to contain only neutral, non-acidic glycoconjugates (probably glycoproteins) which may contain fucose, galactose or mannose. This conclusion is supported by the incorporation of 3H-fucose into the developing lens capsule of regenerating lenses beginning at a stage with initial lens fiber formation. Except for the apparent absence of acidic glycoconjugates in the regenerating lens capsule, these events are similar to those described for developing lenses in chick and mammalian embryos. The differentiation of lens fibers by elongation, loss of organelles and accumulation of fine, electron-dense particles in the cytoplasm also parallels embryonic, lens fiber differentiation.