Fig. 3

Indirect immunofluorescence confocal projections showing fine structures of M. leidyi cydippids preserved using ~ 16% Rain-X® in FSW. a. Aboral view of a whole cydippid labeled with anti-tyrosinated tubulin (magenta), anti-actin (green) and DAPI (blue). b. Single confocal slice representing focal plane approximated by dotted circle in (a), of the region indicated by the boxed area in (a). The slice is through the base of the aboral sense organ (apical organ). Cross-section shows preservation of fine tracts of ciliated furrows leading from comb plates into apical organ and nuclei of the epithelial floor of the apical organ itself [5]. c. Maximum intensity projection showing high magnification view of an apical organ labeled with anti-acetylated tubulin (green) and DAPI (blue). Balancer cilia with statolith nuclei still present are contained within the statocyst dome. Labeled ciliated furrows connect to base of each balancer. d. Differential interference contrast view of the same sample as C overlaid with DAPI channel from the same focal plane to highlight nuclei on balancer cilia. e. Aboral view of a cydippid labeled with anti-tropomyosin alpha 2 chain (green) and DAPI (blue). The smooth muscle cells highlighted line the first branches of the gut’s endodermal canal system. f. DIC image showing the transverse canal (infundibulum) and radial canals (first branches of the endodermal canal system through which digested particles are distributed for absorption) [6] in the same animal as E but at lower magnification. Boxed area represents panel E view. g. Oblique tentacular view showing tentacles emerging from the tentacle sheath. Sample is labeled with anti-eukaryotic ribosome (green) and DAPI (blue). h. DIC image of the sample shown in (g) with comb row and tentacle anatomy indicated by dashed lines. Selected coiled tentilla (finely divided projections of the tentacle) are circled