Carbohydrates in rod and cone light absorbing segments in the firemouth cichlid Thorichthys meeki retina.

Carbohydrates in photoreceptor segments in the retina of the firemouth cichlid Thorichthys meeki are described and compared. The present periodic acid-Schiff (PAS) and lectin results revealed the occurrence of neutral carbohydrates, composed mainly of glycosamine and mannose and glucose, in the light absorbing segments in rods and cones in this species. Unlike in mammals, the retina in this teleost seems to be poor in galactose and galactose-galactosamine units in the light absorbing segments.