Figures & data
Figure 1 Different factors are important for survival in liquid cultures and in colonies. (A) Survival in liquid culture is dependent on stress defense. Stress-defense-deficient population dies rapidly unless stress-resistant mutants appear and overgrow the dying population. (B) Survival in a colony is dependent on metabolic adaptation of the population. Colony cell population switches metabolism as a result of ammonia signal which enables survival of cells at colony margin. Cells in colony centre die and provide nutrients for the benefit of cells at the colony margin. Development of a colony incapable of ammonia signaling is not orchestrated, cells are not able to activate their alternative metabolism and consequently cell death is spread throughout the whole colony. Color of the agar-medium indicates pH changes during colony development: yellow, pH below 6.5; violet, pH above 6.5.
