COMPARATIVE CYTOMORPHOLOGY OF MATURING AMPHISBAENIAN (AMPHISBAENA-ALBA) AND SNAKE (WAGLEROPHIS-MERREMII) ERYTHROID-CELLS WITH REGARD TO HEMOGLOBIN BIOSYNTHESIS

A comparative ultrastructural study on organelles involved in haemoglo bin (Hb) biosynthesis processing in the course of Amphisbaena alba (Am phisbaenia, Squamata, Reptilia) and Waglerophis merremii (Ophidia, Squ amata, Reptilia) erythroid cells maturation, was accomplished; for thi s purpose, erythropoiesis was enhanced by phenylhydrazine hydrochlorid e and saponin, respectively. The fossorial amphisbaenians, which live in an hypoxic environment, denoted a lower metabolic rate than that of snakes; they presented a slow response to intoxication and to anaesth esia, and an apparently slow transformation of erythroid cell organell es for Hb biosynthesis. Iron uptake, probably via transferrin, results in accumulation in the form of siderosomes, which constitute iron sou rces for haeme biosynthesis. The inner compartment membrane of mitocho ndria differentiates to a lamellated body, from which a long doubly la mellated expansion arises for ferruginous compounds and globin polypep tides gathering; by folding upon itself the expansion compartmentalise s all caught material into a prehaemosomal vesicle. which condenses an d changes to a prohaemosome. This stage is followed by a haemosome, wh erein haeme and globin assembly and the final Hb molecule formation ta ke place. Basically, haemosomegenesis is very similar in the two squam ates, as in other vertebrates, except that amphisbaenian erythroid cel ls exhibit haemosomes containing Hb molecules temporarily arranged in a transverse disposition, like steps within the organelle matrix.