Fig. 3. (A) Development on non-nutrient agar of Ax2/gskA– cells pregrown in either axenic medium or bacteria. Cells of a random integrant control were compared with an Ax2/gskA– strain, grown either axenically or in the presence of a bacterial food source. They were then allowed to develop on KK₂-agar and photographed from above. (B) Slug migration on water agar. Cells from a random integrant clone and an Ax2/gskA– strain were grown in axenic medium, developed to the slug stage and allowed to migrate on water agar for 24 hours and towards a unidirectional light source (indicated by arrows). Approximately 80% of the gskA-null structures developed to the slug stage. The structures and their associated slime trails were transferred onto a transparent membrane and visualised by protein staining.