Prof. Dr. Matthias Horn
University of Vienna
Department of Microbiology and Ecosystem Science
Division of Microbial Ecology
Althanstr. 14
A-1090 Wien
phone: +43 1 4277 76608
 Curriculum Vitae as PDF
Microbial symbioses
Symbiosis, the living together of two dissimilar organisms (De Bary, 1898), is a key principle in nature which contributed to the origin of eukaryotes around two billion years ago and continues to have profound impact on the ecology and evolution of extant organisms. My lab is interested mainly in microbial symbioses in which eukaryotes serve as hosts for bacteria. By focusing on selected model systems, we are studying molecular and evolutionary mechanisms underlying and driving these associations.
Chlamydiae are important pathogens of humans but also occur as symbionts of environmental, free-living amoebae. Analysis of only recently discovered chlamydial symbionts such as Protochlamydia amoebophila, Parachlamydia acanthamoebae, and Simkania negevensis, and comparison with their pathogenic counterparts allows us to investigate the evolution of the intracellular life style of chlamydiae and their adaptation to different eukaryotic hosts. This is complemented by the analysis of other, phylogenetically distant bacterial symbionts of amoebae, for example Amoebophilus asiaticus.
Another model for symbiosis and the interaction between microbes and eukaryotes studied in the lab are insects and their bacterial symbionts. We are particularly interested in the less well studied microbial symbionts such as the reproductive manipulator Cardinium hertigii, and those of mealybugs and adelgids.
Common to all our studies is the lack of methods to cultivate the microbial symbiosis partners in the lab. We thus use a spectrum of cultivation-independent, molecular biology techniques including the 16S rRNA approach and fluorescence in situ hybridization, comparative genomics, metagenomics, and transcriptomics using next generation sequencing, phylogenetic and molecular evolution analysis, proteomics, and Raman microspectroscopy.
Research topics
- Microbial symbioses, with emphasis on bacterial symbionts of protozoa and insects
- Evolution of intracellular bacteria
- Microbial genome evolution
- Interaction between intracellular bacteria and eukaryotic host cells
Read more about ...
 Bacterial symbionts of amoebae
 Environmental chlamydiae
 Nucleotide transport proteins in environmental chlamydiae
 Environmental chlamydia genomics and post-genomics
 Genome analysis of 'Candidatus Amoebophilus asiaticus'
 List of publications
Lab members
 Karin Aistleitner,  Astrid Collingro,  Daryl Domman,  Agnes Harreither,
 Lena König,  Ilias Lagkouvardos,  Thomas Penz,  Thomas Schott,
 Frederik Schulz,  Gabriele Schwammel,  Alexander Siegl,  Barbara Sixt,
 Gitta Szabo,  Elena Tönshoff,  Han-Fei Allen Tsao

Information on open research positions can be found here or can be obtained by contacting Matthias. If you are interested in International (non-European only) and Intra-European (European only) Marie Curie Fellowships in our lab, then please get in touch for details.