Figure 2
Ventral views of Botryllus schlosseri colonies grown on glass slides.
(A) A colony formed by two star shaped systems of six and twelve adult zooids (z), respectively, is embedded in the common transparent tunic (t). The crown of ampullae (am) is visible at the periphery of the colony. (B) Peripheral region of a colony in which the main components of the colonial circulatory system (CCS) are recognisable: the marginal vessel (mv), some radial vessels (rv) and some ampullae (am). (C) Detail of an operated colony, two hours after the ablation of the CCS in front of four adult zooids. Arrows indicate the lateral cut edges. (D) The same colony of (C), injected with PBS, one day after ablation. The thin line of new tunic, penetrated by vessel stumps and small ampullae (arrowheads), covers the previously exposed zooids. (E–F) The same colony showed in (C), two and three days after ablation. Both lateral (arrows) and proximal (dotted line in (E)) cut edges moved to reach the tunic profile external to the ablated region. In the regenerated tunic, the marginal vessel (mv) and the crown of ampullae appear almost fully regenerated in (F) with respect to the day before (E). Similarly, more regenerated radial vessels are visible in (F) with respect to (E). (G, H) Magnifications of CCS regenerated region in colonies. Elongating new vessels (white arrowhead) and sprouts (black arrowheads) are well visible. Scale bars: 1 mm in (A, C–F); 500 μm in (B, F); 100 μm in (G). Images were organized with CorelDRAW X4 (Corel Corporation).
