Cryo-Transmission Electron Microscopy (CTEM) - of unstained, cryo preserved extruded Anncaliia algerae polar tubes in vitreous ice.
A. A PT whose outer edge is composed by 2–3 layers of alternating electron lucent (EL) arrow and medium dense parallel bands of material. The central portion of the tube contains ED material that is finely stippled. Bar is 50nm.
B. Organized arrays of polar tube protein on the surface of a PT. Bold arrows indicate the angle of protein orientation to the PT shaft, suggesting a helical organization. The fibrillar material visible along the tube is obvious and indicated by arrows. Bar is 50nm.