EARLY DEVELOPMENT IN FUCUS-SPIRALIS - ANALYSIS OF SURFACE GLYCAN MOIETIES AND CELL-DIFFERENTIATION USING LECTINS

Glycan moieties of cell surfaces have been implicated as mediators in cell-cell interaction, cell differentiation and control of early devel opment. At present, glycan moieties of cell surfaces are currently ana lyzed using lectins. Fucus spiralis is widely employed to study early development. In this work, the early development of Fucus spiralis emb ryos was analyzed using FITC-labelled lectins. The cell surfaces of sp ermatozoa showed more single patterns of glycan moieties than oocytes. However, just after fertilization young zygotes lose lectin binding s ites suggesting important changes on their cell surface. Soon afterwar ds, zygotes polarize their surface glycans, and these show more divers ity at rhizoid poles than at thallus poles. In early embryos, the rhiz oid cells appear as a differentiated cell with more lectin binding sit es than the other cells. In conclusion, the analysis of lectin binding sites reveals that young fucoid zygotes are highly polarized cells wi th two well-differentiated poles (rhizoid and thallus), and the two ea rliest cells of Fucus spiralis embryos are differentiated on their sur face.