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Dr. Nikolaus Leisch

Project Leader

Department of Symbiosis

MPI for Marine Microbiology
Celsiusstr. 1
D-28359 Bremen




+49 421 2028-7600

Dr. Nikolaus Leisch

Main Research Interests

As an organismal biologist, I study the interaction between animal hosts and their microbial symbionts to understand the detailed interplay between the domains of life. I work on marine invertebrates which associate with few selected microbes. The microbial partners expand the metabolic capabilities and allow the animals to be successful in habitats that would often be inhospitable to them.

My team, consisting of Miguel Ángel González PorrasMaximilian Franke and I are looking into how microbes can colonize and persist in eukaryotic tissue and organelles and how this association can impact the development of the host.  We are using correlative imaging methods to understand how each symbiosis is structured, who the key players are, where the symbionts are located and what morphological adaptations both partners have undergone to make the symbiosis work. We combine whole animal 3D reconstruction with fluorescent labelling approaches and high resolution analysis using electron microscopy.

To this end, we developed and optimized a range of methods to overcome the limitations one faces working with non-cultivable organisms. From improving sample preservation during field excursions, reconstructing pro- and eukaryotic lifecycles in silico, to combining phylogenetic identification with excellent ultrastructural resolution. Moreover, we use genomic data from both host and symbiont to understand their evolutionary background. Together with transcriptional data we predict the respective capabilities of both partners and use these insights for subsequent experiments and analyses.
It is this integration of sequencing-based findings with morphological and molecular imaging data that characterizes my team’s holistic view on these symbioses. It enables us to carefully dissect the system, each partner’s needs and contributions, as well as challenge prevailing dogmas on how bacteria divide, what makes a parasite a parasite or how a host can be fed by its symbiont.

(Some of) the organisms I work with

A deep-sea mussel of the species Bathymodiolus childressi
A mussel of the species Bathymodiolus childressi from the deep-sea in the Gulf of Mexiko.
The mouthless nematode of the genus Astomonema
The mouthless nematode of the genus Astomonema. The white color of the worm comes from symbiotic bacteria, that the worm carries inside its body.
The marine nematode Eubostrichus dianeae as seen in the scanning electron microscope. The "fur" covering the nematode are bacteria that feed their host.
The marine nematode Eubostrichus dianeae as seen in the scanning electron microscope. The "fur" covering the nematode are bacteria that feed their host.



A Assié*, N Leisch*, D V Meier, H Gruber-Vodicka, H E Tegetmeyer, A Meyerdierks, M Kleiner, T Hinzke, S Joye, M Saxton, N Dubilier and J M Petersen (2020). "Horizontal acquisition of a patchwork Calvin cycle by symbiotic and free-living Campylobacterota (formerly Epsilonproteobacteria)." The ISME Journal 14(1): 104-122.


Gruber-Vodicka HR*, Leisch N*, Kleiner M, Hin­zke T, Liebeke M, Mc­Fall-Ngai M, Had­field MG, Dubilier N. 2019. Two in­tra­cel­lu­lar and cell type-spe­cific bac­terial sym­bionts in the placo­zoan Tricho­plax H2. Nature Microbiology doi:10.1038/s41564-019-0475-9

Jäckle, O, BKB Seah, M Tietjen, N Leisch, M Liebeke, M Kleiner, JS Berg and HR Gruber-Vodicka(2019). A chemosynthetic symbiont with a drastically reduced genome serves as primary energy storage in the marine flatworm Paracatenula. Proceedings of the National Academy of Sciences USA 116(17) 8505-8514.


Kitzinger K, Koch H, Lücker S, Sedlacek CJ, Herbold C, Schwarz J, Daebeler A, Mueller AJ, Lukumbuzya M, Romano S, Leisch N, Karst SM, Kirkegaard R, Albertsen M, Nielsen PH, Wagner M and Daims H (2018). Characterization of the First “Candidatus Nitrotoga” Isolate Reveals Metabolic Versatility and Separate Evolution of Widespread Nitrite-Oxidizing Bacteria. mBio 9:4 e01186-18 10.1128/mBio.01186-18

Pende N, Wang J, Weber PM, Verheul J, Kuru E, Rittmann SKMR, Leisch N, VanNieuwenhze MS, Brun YV, den Blaauwen T, Bulgheresi S (2018) Host-Polarized Cell Growth in Animal Symbionts. Current Biology 28, 1039-1051 10.1016/j.cub.2018.02.028


Assie A, Borowski C, van der Heijden K, Raggi L, Geier B, Leisch N, Schimak M P, Dubilier N, and Petersen J M. 2016. A specific and widespread association between deep-sea Bathymodiolus mussels and a novel family of Epsilonproteobacteria. Environmental Microbiology Reports. 10.1111/1758-2229.12442

Leisch N, Pende N, Weber P M, Gruber-Vodicka H R, Verheul J, Vischer N O, Abby S S, Geier B, den Blaauwen T, and Bulgheresi S. 2016. Asynchronous division by non-ring FtsZ in the gammaproteobacterial symbiont of Robbea hypermnestra. Nature Microbiology 2:16182. 10.1038/nmicrobiol.2016.182

Montanaro J, Gruber D, and Leisch N. 2016. Improved ultrastructure of marine invertebrates using non-toxic buffers. PeerJ 4:e1860. 10.7717/peerj.1860


Montanaro J, Inic-Kanada A, Ladurner A, Stein E, Belij S, Bintner N, Schlacher S, Schuerer N, Mayr U B, Lubitz W, Leisch N, and Barisani-Asenbauer T. Escherichia coli Nissle 1917 bacterial ghosts retain crucial surface properties and express chlamydial antigen: an imaging study of a delivery system for the ocular surface Drug Design, Development and Therapy 2015(9):3741-3754


N Pende*, N Leisch*, H R Gruber-Vodicka, N R Heindl, J Ott, T den Blaauwen and S Bulgheresi Size-independent symmetric division in extraordinarily long cells. Nature Communications (doi:10.1038/ncomms5803)

J A Ott, H R Gruber-Vodicka, N Leisch and Judith Zimmermann Phylogenetic confirmation of the genus Robbea GERLACH, 1956 (Nematoda: Desmodoridae, Stilbonematinae) with the description of three new species. Systematics and Biodiversity 12(4):434-455

J A Ott, N Leisch and H R Gruber-Vodicka Eubostrichus fertilis sp. n., a new marine nematode (Desmodoridae, Stilbonematinae) with an extraordinary reproductive potential from Belize, Central America. Nematology 16(7): 777-787

Michaela Stieglmeier, Andreas Klingl, Ricardo E. J. Alves, Simon Rittmann, Michael Melcher, Nikolaus Leisch and Christa Schleper Nitrososphaera viennensis sp. nov., an aerobic and mesophilic ammonia-oxidizing archaeon from soil and member of the novel archaeal phylum Thaumarchaeota International Journal of Systematic and Evolutionary Microbiology 64(8):2738-2752


N Leisch, J Verheul, N R Heindl, H R Gruber-Vodicka, N Pende, T den Blaauwen and S Bulgheresi. Growth in width and FtsZ ring longitudinal positioning in a gammaproteobacterial symbiont Current Biology 22(19): R831-R832

U Dirks, H R Gruber-Vodicka, N Leisch, S Bulgheresi, B Egger, P Ladurner and J A Ott Bacterial Symbiosis Maintenance in the Asexually Reproducing and Regenerating Flatworm Paracatenula galateia. PLoS One 7(4): e34709.

V Zheden, J von Byern, A Kerbl, N Leisch, Y Staedler, I Grunwald, A M Power, W Klepal Morphology of the cement apparatus and the cement of the buoy barnacle Dosima fascicularis (Ellis & Solander, 1786) (Crustacea, Cirripedia, Thoracica, Lepadidae) The Biological Bulletin 223(2): 192-204


H R Gruber-Vodicka, U Dirks, N Leisch, C Baranyi, K Stoecker, S Bulgheresi, N R Heindl, M Horn, C Lott, A Loy, M Wagner and J A Ott. Paracatenula, an ancient symbiosis between thiotrophic Alphaproteobacteria and catenulid flatworms. Proceedings of the National Academy of Science of the United States of America 108(29): 12078-12083

N Leisch, U Dirks, H R Gruber-Vodicka, M Schmid, W Sterrer and J A Ott Microanatomy of the trophosome region of Paracatenula cf. polyhymnia (Catenulida, Platyhelminthes) and its intracellular symbionts. Zoomorphology 130(4): 261-271

U Dirks*, H R Gruber-Vodicka*, N Leisch, W Sterrer and J A Ott A new species of symbiotic flatworms, Paracatenula galateia sp. nov. (Platyhelminthes: Catenulida: Retronectidae) from Belize (Central America). Marine Biology Research 7(8): 769-777

*these authors contributed equally


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