Nature of the packing of ribosomes within chromatoid bodies.

Optical Fourier transformns, made of electron mnicrographs of the crystalline array of ribonucleoprotein known as chromatoid bodies of Entamoeba invadens, have been interpreted as the transforms of a helix of 12 nodes in five turns. A model shows that this helix may be built of spheres 180 angstroms in diameter, placed at a radius of 150 angstroms. The optical transform of the model is very similar to the transform of the original electron micrograph.