300599 UE Molecular ecology of Cyanobacteria (2009S)

Cyanobacteria occur in freshwater and in oceans and show a range of ecophysiological adaptations to various environments (for example nitrogen-fixation, pigments, gasvesicles, bioactive compounds). Those adaptations frequently result in colonization of extreme habitats or even dominance. On the other hand cyanobacteria have the ability to adapt quickly to changing environmental conditions, for example anthropogenic influences leading to the eutrophication of freshwater and brackish water. This is possible due to a broad ecophysiological amplitude, that can also be observed from the variability of genomes sequenced from closely related isolates of one species. In this course molecular techniques will be combined with phylogenetic techniques, in order to study ecophysiological adaptations of cyanobacteria to their environment. Cyanobacteria will be isolated from the pelagic zone of a lake, and specific selected gene regions will be amplified by means of PCR and sequenced. These gene regions will be characterized with regard to their function, and analysed for substitutions resulting in possible altered functions of the corresponding enzyme. The evolutionary analysis will give information on putative selective pressures or possible relaxation of selective constraints on speficic gene regions.