Fig 1.
Generalized schematic of acorn barnacle and female reproductive tissue.
A) Sagittal schematic highlighting the main body, the main components and showing the location of the LCT, and the sub-mantle region. B) Schematic identifying different structures of the female reproductive system and its relation to LCT.
Fig 2.
Brightfield images of partially demineralized A. amphitrite and exposed LCT.
A) Top view of partially demineralized A. amphitrite with LCT exposed at the periphery. Dashed red box represents area under higher magnification in panel B), showing greater detail of the exposed LCT including the pink hue arising from the speckled epithelial layer. C) Image of exposed LCT showing their termination into channel-like projections toward the barnacle leading edge. D) Top-down view of partially demineralized A. amphitrite highlighting the longitudinal cavities containing the tissue of interest.
Fig 3.
A) Brightfield image under lower magnification showing the interior texture. B) Higher magnification image of LCT stained with Bodipy FL (green, lipophilic) and Sypro Ruby (red, protein). C) Brightfield and D) confocal image of a sagittal section of LCT and submantle tissue stained with DAPI showing the presence of nuclei throughout. An epithelial layer is also present along the bottom edge.
Fig 4.
H & E stained sagittal section of A. amphitrite.
Four prominent components are labeled: portions of the LCT, the main body, female reproductive tissue, and underlying cuticular tissue.
Fig 5.
Sagittal sections of LCT stained with H&E.
A) Entire view of LCT in relation to the edge of A. amphitrite. B) Magnified image of A) showing the various textures and staining profile. C) Another zoomed image of A) highlighting the presence of nuclei and clusters of lipophilic spheroids. D) Sagittal section showing connection between the LCT and the mantle parenchyma.
Fig 6.
H&E stained transverse A. amphitrite sections.
A) Low magnification image of LCT and sub-mantle tissue containing the ovaria. B) Higher magnification image of A) highlighting continuity between LCT and sub-mantle tissue. C) Image of two ovaria showing oogenesis at different developmental stages.
Fig 7.
Venn diagram providing an overview of the protein profile of LCT and sub-mantle tissue.
Out of a total of 629 identified proteins, 48% (305) were identified in both tissues.
Fig 8.
Overview of top 50 proteins identified within LCT.
A) Heat map of logarithmically transformed data. Spectra assigned to vitellogenin are in bold. Data are sorted by the combined average of the LCT A and B values. B) Position of conserved domains present in A. amphitrite vitellogenin proteins: Vitellogenin_N superfamily, DUF1943 (Domain of Unknown Function), and VWD (von Willebrand Domain) superfamily. C) Predicted general biological processes for the proteins in A). Abbreviations: LCT: longitudinal canal tissue; SMT: sub-mantle tissue; SIPC: settlement inducing protein complex; HSPG: heparan sulfate proteoglycan; ATP: adenosine triphosphate; WSP: waterborne settlement pheromone; GGT: gamma-glutamyltransferase.