Journal of Cell Science, Vol 11, 295-303, Copyright © 1972 by Company of Biologists

Submitted on November 19, 1971

Helical Filaments in the Glial Cells of the Locust (Schistocerca Gregaria)

¹ Department of Zoology and Comparative Physiology, University of Birmingham, Birmingham 15, England

Organelles consisting of a spirally wound filament are present in the cytoplasm of glial cells in Schistocerca gregaria. The diameter of the helix is 32.5 nm with an average pitch length of 23.0 nm. The filament is comprised of only a single strand about 6.0 nm in diameter which appears to be made up of a chain of globular subunits. In order to distinguish between these helical structures and organelles made up of more than one strand, i.e. microtubules and microfilaments, it is suggested that they be termed ‘microhelices’

The structural features of microtubules, microfilaments and microhelices are compared, and the possible functions of microhelices are discussed in the light of what is known about the physiological properties of microtubules.

It is pointed out that the microhelix is structurally very similar to the internal ribonucleoprotein component of the influenza virus, and that the possibility cannot be discounted that the microhelix might be a viral particle.