NeuroFIG 37: Ultrastructure of the anterior deirid sensillum.

A. SEM, left lateral view. Anterior deirid sensilla are located along the alae, at the posterior of the head, near the terminal bulb. (Inset) Left deirid papilla, magnified. (Image source: D.H. Hall and C. Marks.)
B. Epifluorescent image from a transgenic animal expressing the reporter gene dat-1::GFP in ADE neurons, left lateral view. ADEso cells (pink), ADEsh cells (green), and the pharynx (transparent green) are drawn on the image to indicate the relative positions of each cell. A branch from the dorsal ADE process projects to the lateral body wall to form the cilium. Processes from the socket cell and the sheath cell are the other two components of the sensillum. The ventral process from the ADE neuron travels within the deirid commissure before entering the retrovesicular ganglion and terminates shortly after entering the ventral ganglion.
C. Graphic rendition depicting the cells of the anterior deirid sensillum, transverse view, rotated 90°. The cilium of the ADE neuron, which is mechanosensory, terminates within the cuticle of the alae and is anchored to it through a nubbin.
D–F. TEMs of an anterior deirid sensillum, transverse sections. Bar, 0.5 μm. D. Section through the sensillar ending. Electron-dense cytoplasmic material (TAM) is seen in the center of the cilium at its tip. (Arrowheads) Adherens junctions between the socket and seam cells. E. Section through the junction of the socket and sheath cells. (Arrowheads) Adherens junctions between socket and seam cells and the self-junction of the socket cell. F. Section through the transition zone of the ADE cilium. Nine doublets are aligned along an apical ring and are connected to the membrane through Y-shaped fibers. Three to four singlet MTs are seen inside. (Arrowheads) Adherens junctions. (Image source: [D] [MRC] N2 deirid adult 2753-18, [E] [MRC] N2 deirid adult 2753-13, [F] [Hall] B306H 2447.)

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