ULTRASTRUCTURAL CYTOLOGY OF MATURING ERYTHROID-CELLS IN A FOSSORIAL REPTILE (AMPHISBAENA-ALBA) WITH REFERENCE TO HEMOGLOBIN BIOSYNTHESIS

Ultrastructural changes of organelles involved in hemoglobin (Hb) bios ynthesis were studied in immature peripheral erythrocytes of Amphisbae na alba (Amphisbaenia: Reptilia), Iron uptake (probably via transferri n) and accumulation results in formation of siderosomes, which serve a s an iron source for heme biosynthesis, Differentiation of the mitocho ndrial inner chamber results in a lamellated body, which then produces a lateral expansion; this expansion retains ferruginous compounds and globin polypeptides and, later, folds upon itself to form a prehemoso mal vesicle, Vesicle content condenses, and iron in an amorphous state associates with the partially coiled vesicle membrane, Invagination o f the membrane gives rise to a prohemosome; narrowing of the broad int ralamellar spaces and reduction of overall diameter results in formati on of a hemosome. Stages of hemosomegenesis in maturing erythroid cell s of Amphisbaena alba are similar to those in other vertebrate groups; the significant difference is the periodical and temporary transverse alignment of Hb molecules in the organelle matrix of some of the hemo somes. Electrophoresis reveals a similar Eight Hb migration rate patte rn in both organellar and cytoplasmic fractions; the cytoplasmic fract ion also shows a heavy Hb pattern with a lower migration rate.