Figure 7

The larval brain of Maritigrella crozieri - CSLM micrographs of neural components. (A-E) Ventral views of the anterior end of the larvae. (A) AcTub (green) and 5HT (magenta) expression showing the posterio-lateral extension of the dorso-lateral nerve cords (dlc) and anterior and anterior-lateral extension of intra-epithelial neurites (ien) to the apical plate (ap) and surface from the cerebral commissures (cc). 5HT expression is pronounced in the commissural cell bodies (ccb) and median cluster (mc). The protonephridia (pnp), intra-epidermal cells (iec) and cilia in the intestine (in) show acTub IR and rhabdites (rb) are visible in the epidermis. Inset shows neural connection (arrow heads) between the intra-epidermal cells and the cerebral commisure. (B) FMRFamide (blue) and acTub (green) expression, note lack of FMRFamide expression in commissural cell bodies but immunoreactivity in the apical plexus (apl) above the cerebral commissure and in two nerves connecting the brain to the pharynx (double arrowheads). Inset shows FMRFamide and acTub expression in cerebral commissure. (C, D, E) Dual labeling of acTub (green) and FMRFamide and 5HT simultaneously (magenta) showing; (C) ventral section of brain with commissural cell bodies, cerebral commissure, apical plexus and intraepithelial neurites, (D) dorsal section of brain consisting of median cluster and intraepithelial neurites in close proximity to intra-epidermal cells (iec) and apical cilia (ac). (E) Optical section at the focus plane of the cerebral eyes (ce) either side of median cluster, acTub expressing optic nerves (on) visible. (F) Left lateral view of anterior end of larva showing FMRFamide (blue) expression in the median cluster dorsal to the apical plexus. FMRFamide and acTub IR is seen in epidermal eye nerve (een) extending dorsally to the epidermal eye (asterisk) Inset shows neuron (arrowhead) from intra-epidermal cell passing through the basement membrane. Scale bars 50 μm, inset in B 25 μm.