A double-layered lamella was positioned between the layer of microtubules and a deeper layer of mitochondrion-derived organelles (Figures 4A-B, 4D). The mitochondrion-derived Raf activation organelles were discoidal in shape, were bounded by two membranes and lacked mitochondrial cristae or inclusions such as kinetoplasts (Figures 4A-B, 4E). Moreover, we did not observe any evidence

of euglenid-like pellicle features, such as the presence of S-shape proteinaceous strips or discontinuities in the layer of microtubules. Nucleus, Vestibulum and Associated Pockets An anterior nucleus was positioned near the ventral side of the cell and contained a prominent nucleolus and condensed chromosomes (Figures 3A, 3C-D). The vestibulum was positioned directly above the nucleus as this space passed from the ventral, subapical opening toward the dorsal side of the cell (Figure 3C). The vestibulum then extended posteriorly along the dorsal side of the cell and branched into three distinct pockets: (1) a novel “”extrusomal pocket”", (2) a flagellar pocket and (3) a feeding pocket (Figures 3A, 3C; described in more detail below). A battery of longitudinally arranged extrusomes was connected to the base of the extrusomal pocket and was nested within a notch on the dorsal side of the ventral nucleus (Figures 1B, 3A, 3C). Each extrusome was about 160 nm in diam. (Figure 3G). The battery of extrusomes

was indistinguishable from the feeding rods of euglenids when viewed with the light microscope, and discharged as a single unit through the anterior opening (Figures 1B, 1H). The flagellar pocket was located selleck products on the dorsal side of the cell and contained two flagella that inserted at the bottom of the pocket (Figures 6, 7; described in more detail below). The feeding pocket was located to the right of the flagellar pocket and extended horizontally before tapering posteriorly toward the ventral side of the cell (Figures 8, 9; described in more detail

below). Florfenicol Figure 6 Transmission electron micrographs (TEM) showing paraxonemal rods in the flagella, the flagellar transition zone and the basal bodies of Calkinsia aureus. A. Longitudinal section of the dorsal flagellum (DF) showing the flagellar transition zone and the dorsal basal body (DB) (bar = 500 nm). B-J. Non-consecutive serial sections through the DF (B), the flagellar transition zone (C-G), and the DB (H-J) as viewed from anterior end (images at same scale, bar = 200 nm). B. Section showing the 9+2 configuration of axonemal microtubules and the tubular paraxonemal rod (arrow) in the DF. C. Section showing termination of central microtubules and the 9+0 configuration of axonemal microtubules. D. Section showing the transition zone through an outer concentric ring associated with nine electron dense globules inside of each doublet and faint spokes that extend inward from the each globule (see L for a diagram of this micrograph). E.