Dr Eva Nowack, Dusseldorf
From Bacterial Endosymbionts to Early Organelles
The acquisition of mitochondria and plastids resulted in novel cell types containing new bioenergetic and biosynthetic compartments. These evolutionary processes were initiated more than a billion years ago by the endosymbiotic uptake of bacterial endosymbionts. More recently established bacterial endosymbioses that engage a broad range of bacterial phyla are found across the eukaryotic tree of life and provide the host with novel physiological capabilities that allow it to colonize and propagate in new ecological niches. Over evolutionary times, endosymbiont genomes tend to reduce. The gene repertoire of the host and endosymbiont genomes can become highly complementary, which indicates an intricate integration of metabolic processes between the partner organisms. Molecular mechanisms that mediate these interactions, however, are largely unknown. We explore the molecular base for host/symbiont interactions through genomic, proteomic, and molecular/genetic approaches using the amoeba Paulinella chromatophora (Cercozoa, Rhizaria) that contains nascent photosynthetic organelles of cyanobacterial origin and the trypanosomatid Angomonas deanei (Kinetoplastea, Excavata) that contains nutritional b-proteobacterial endosymbionts.