Mastigonemes are hair-like structures attached to the protistan flagella. (A) Schematic presentation of C. Reinhardtian and its flagella. Enlarged the cross-view of the flagellum, showing the central aperture, and the surrounding nine microtubule doublets. Mastigoneme branches from DMT-4 and -8 (colored in purple). (B) Negative stain image of mastigoneme attached to the flagella from cw15 cells (bar = 500 nm). (C) Statistical analysis of mastigoneme length was performed using 37 mastigonemes derived from 10 negative stain images. (D) Tomographic slices emphasize the axoneme (inner of the white dash line), glycocalyx (outer of the white dash line), and mastigonemes (arrow; bar = 100 nm). (E) Cryo-EM image of mastigoneme filaments attached on the axoneme. (Label and bar are the same as in D.)