In Vitro Preparation of the Early Squid Blastoderm

Abstract

The early squid embryo (Loligo vulgaris) presents a “bi-dimensional” blastoderm architecture as well as cell structural and physiological properties, which makes it worthwhile for studies on individual cell migration in vivo and in situ and cell-to-cell communication devices (Marthy 1982, 1985; Segmüller and Marthy 1989; Marthy and Dale 1989). However, whereas the size of the egg, its translucency and the dimension of the blastoderm (egg: 2,2 × 1,5 mm in size; blastoderm: 0,5 – 1,5 mm in diameter, during the preorgano-genetic stages) are well appreciated when working on living material, the shape of the egg (a hen’s egg form), on which the blastoderm expands from its narrow pole over the egg surface, is less advantageous. In fact, the more the blastoderm grows towards the equatorial egg region; the less the strong curvature of the egg allows a simultaneous precise focusing on the central and the peripheral zones of the blastoderm (from an “on top” view). For an optimum observation of the blastoderm and/or manipulations on it (e.g. microsurgery, intracellular microinjection), a totally “flat” blastoderm is needed. This preparation can be achieved in principal by three techniques of which the latest will be described in more detail in this paper: