Figure 2
Immunohistochemistry of primary podia (PP) development in the echinus rudiment (EcR) of 8-arm plutei. (A) Left-side trunk. Inset (a), higher magnification of a box (a). Arrow; ciliary band-associated strands. Arrow head; connection between the anterior epaulette (asterisk) and the GAD-immunopositive (GAD-IS) blastocoelar network. Dual asterisks; posterior epaulette. (B) Higher magnification shown by a box (b,c) in (A). Arrow; ciliary band-associated strand. Asterisk; anterior epaulette. (C) Optical cross-section of EcR shown by a box (b,c) in (A). Arrow; GAD-IS PP surface. Asterisk; anterior epaulette. (D,E) Older plutei than (A). Arrow; anus muscle ring. (D) PP-encased EcR. (D1) Higher magnification of a box (d1,d2) in (D) shows GABAAR-IS PP. (D2) The same area as (D1) shows faint tropomyosin (TM)-IS PP at a similar region to GABAAR-IS sites in (D1). (E) Slightly older pluteus than (D). (E1) Higher magnification of a box (e1,e2) in (E) shows faint GABAAR-IS PP. (E2) Same area as (E1) shows intensified TM-IS PP. (F) Further developed GAD-IS PP than (E). (F1) Asynchronous GABA-IS expression among PP. (F2) Merged image between (F) and (F1). Both ISs are missing at the tip of PP (arrowheads). (G1,G2) Three-D image of trunk. aEpt; anterior epaulette. pEpt; posterior epaulette. Asterisk; larval opening. (G1) Outer surface view by ImageJ. Red arrowheads; ciliary band-associated strand. (G2) Inside out image of (G1) by Avizo. (H-H2) Optical cross-section of a PP shown by box (h) in (G1). Red arrowhead; periphery of the opening. (H) Optical cross-sections of GAD-IS image. (H1) TM-IS image. (H2) Merged image between (H) and (H1). la; larval arm. N; nuclei, Ph; pharynx. Stm; stomach. TM; tropomyosin. Scale bars = 100 μm (A,D,E,F), 50 μm (B,C,D1,E1), 75 μm (G1), 20 μm (H).
