In the project: Adaptationof algae we investigated to which extent bacteria are capable of storing information about
previous environmental events and whether stored information is passed on to daughter cells during cell division.
Our special attention was focussed on how stored information determines future modes of adaptation in an
anticipatory way and whether thereby a rudimentary learning can be observed.
For this purpose we studied the "memory" of cyanobacteria for phosphate fluctuations to which they had been
exposed during their preceding growth. We could show that cyanobacteria are able to store information about
certain fluctuation patterns in the external phosphate concentration in the properties of their membranes and that
these properties are then transmitted to daughter generations, where they are maintained even after cell division.
Information is stored for a prolonged period of time, if during an environmental constellation at least two
interdependent energy converting subsystems of the cell adjust themselves adaptivly to one another and at the same
time to the prevailing phosphate regime, thereby forming a stable ensemble. If such stable ensembles are passed on
to daughter generations by cell division they influence in a distinct way a de novo adaptation to newly occurring
phosphate fluctuations. Whether in this case a temporary rise of the external phosphate concentration is perceived
as a stimulus to which an adaptive response is favorable for subsequent survival or whether it is ignored by the
population then depends on the history of preceding stimuli which the population had been experienced during its
growth.