A Study of the Structure and Gliding Movement of Gregarina garnhami

SYNOPSIS The structure and gliding movement of Gregarina garnhami Canning, a eugregarine found in the midgut of the desert locust, Schistocerca gregaria , have been studied by light microscopy and transmission and scanning electron microscopy (EM). Ultrastructural studies revealed that the cytoplasm of G. garnhami is separated from the epicyte folds by a basal lamina. The pellicle consists of 3 membrane layers. At the tips of the epicyte folds there are 2 sets of longitudinally oriented filaments. An ectoplasmic network is present in the ectoplasm and the endoplasm contains numerous paraglycogen granules. The effect of cytochalasin B on G. garnhami was studied. Examination of scanning EM preparations of gliding and stationary gregarines yielded inconclusive results. In some instances the epicyte folds were thrown into waves; in others the folds were straight, regardless of treatment before fixation. Gregarina garnhami glides through its environment without any apparent deformation in shape. As it moves, a mucus trail is left behind it. Phase-contrast observations were made of centrifuged gregarines in which the endoplasm was displaced. Centrifuged gregarines continued to glide. Displacement of the endoplasm allows visualization of the epicyte folds in gliding animals. No lateral waves were seen in the epicyte folds of gliding centrifuged animals.