Microtubule bundles in the hindgut epithelium of the woodlouse Oniscus ascellus

Abstract

Cytoplasmic microtubules are now recognized as universal components of both plant and animal cells ( 10, 15, 16 ) and have been strongly implicated as intracellular cytoskeletal elements. In addition to supplying asymmetric cells with both structural rigidity and form (e.g., 3, 5, 18 ), roles have been suggested for microtubules as orienting structures with respect to cellular organelles (e.g., 12, 15 ) and as units involved in contractile processes and cell movement (e.g., 7, 14 ). In many cells, systems of microtubules have been observed for which no immediate function could be postulated. The present study describes an unusual system of microtubular bundles in the hindgut epithelial cells of the terrestrial isopod, Oniscus ascellus . These cells, which bear certain resemblances to cells thought to be involved in the movement of water and ions, display considerable intracellular polarization, especially with respect to their mitochondrial populations. The electron micrographs presented here strongly suggest a correlation between the microtubular elements and the oriented structural arrangements of the cell.