Fig. 7
From: Ancestral role of Pax2/5/8 in molluscan brain and multimodal sensory system development
Expression of Ntu-Pax2/5/8 during larval development of the bivalve Nucula tumidula. Dorsal (d)–ventral (v), apical (a)-abapical (aa), and left (l)-right (r) axes indicate the orientation. Blastopore and mouth is marked with an asterisk and the position of the apical organ is encircled. a Ntu-Pax2/5/8 expression in approximately five cells (arrowheads) close to the blastopore of a 24 h post fertilization (hpf) old gastrula. Inset: Sketch drawing of Ntu-Pax2/5/8 expression (blue) in a gastrula (left view and apical faces up). b-c 5–7 cells (arrowheads) express Ntu-Pax2/5/8 below the test cells and close to the mouth of the early pericalymma larva (3 dpf). d Confocal reflection (Ntu-Pax2/5/8 expression in red) and autofluorescence (grey) scan of a single optical section of an early larva (3 dpf; similar to (b & c)). e A further developed specimen (8 dpf) with Ntu-Pax2/5/8 expression in the mantle (m). f Ntu-Pax2/5/8 is expressed in the mantle including the shell gland (sg) (same specimen as shown in (e). g Confocal reflection (Ntu-Pax2/5/8 expression in red) and autofluorescence (grey) scan of a single optical section of the same specimen as shown in (f). h This further developed larva (8 dpf) expresses Ntu-Pax2/5/8 bilaterally along the dorsal and apical mantle (arrowhead). i Late larvae (12 dpf) express Ntu-Pax2/5/8 along the dorsal and ventral mantle (arrowhead). j 12 dpf old larva of the same stage as the one shown in I with stronger Ntu-Pax2/5/8 expression in the dorsal and ventral (arrowhead) mantle. k Same specimen as shown in J with Ntu-Pax2/5/8 expression in the dorsal and ventral mantle (arrowheads) but not the foot (f). l Sketch drawing summarizing the Ntu-Pax2/5/8 expression domains (blue) in a metamorphic competent pericalymma larva before settlement. Abbreviations: an, anus; at, apical tuft; e, esophagus; f, foot; pc, perivisceral cavity; tc, test cell; s, shell; stm, stomach. Scale bars: 30 μm