Motor behaviour of Amoeba proteus during glutaraldehyde fixation

The glutaraldehyde + polyethylene glycol fixative, recommended to study the differentiations of contractile structures in Amoeba proteus related to locomotion, provokes well defined motor responses during the fixation procedure, expressed mainly in the reversal of endoplasmic streaming and retraction of all advancing fronts. It may improve the picture of the motile apparatus by reinforcing contraction and inducing it even in formerly expanding cell regions. It seems, therefore, that any conclusions about the original conformation and topography of the contractile cell layer during normal locomotion based on this method are subject to caution, unless confirmed by other methods, in particular by in vivo techniques.