ADHESION TO THE SUBSTRATUM IMPROVES THE MOTILITY OF AMEBA-PROTEUS IN THE ABSENCE OF A CELL-NUCLEUS

Anucleated fragments of Amoeba proteus obtained by dissection and kept on an untreated glass surface fail to adhere to this substratum, lose motor polarity, and stop moving, at least for several hours. If they are transferred after the operation to a highly adhesive surface (poly lysine-coated glass), they adhere to the substratum, although locomoti on is not spontaneously restored. However, after exposure to a light-s hade difference along their body they start moving towards the shaded area and continue locomotion as long as the photic stimulus is acting. Disorganisation of the F-actin cytoskeleton of anucleated fragments w as observed on the untreated glass but reorganization on the polylysin e-coated surface. The anucleated fragments can show transient recovery of slight spontaneous motor activity and react promptly to external s timuli after up to several days on untreated glass. These intermittent activity periods are enabled by reconstruction of F-actin cyloskeleto n in the anucleated fragments during their temporary adhesion to the g lass. It is concluded that the injurious effect of cell nucleus remova l on the locomotor capacity of amoebae can be compensated by the simul taneous enhancement of cell adhesion and application of a stimulus res toring the motor polarity of the cell. The compensation is achieved by cytoskeletal reorganization.