Polyphasische Taxonomie, Kerngenom und Lebenszyklus von Rhodopirellula-Stämmen

Abstract

This thesis focused on three major projects dealing with the planctomycetes of the species Rhodopirellula baltica. In a polyphasic taxonomic study the morphological, physiological and chemotaxonomic characteristics of 17 newly isolated strains were investigated. Based on the obtained results and phylogenetic data ten new Rhodopirellula species were introduced along with one new genus. The physiology of the strains was studied with regard to the influence of ammonium on their life style. Using flow cytometry an increase of aggregated cells compared to single cells was observed parallel to an increase of the ammonium concentration. In chemostat cultures an ammonium shock induced the formation of a R. baltica biofilm by attachment of cells to the fermenter wall. With ten strains the Rhodopirellula core genome was determined by microarray analysis and genome sequencing. Both methods were compared. The R. baltica core genome contains 3314 shared genes according to microarray analysis and 4232 shared genes according to genome annotation. The investigations of this work are the basis for future comparative studies between Rhodopirellula species.