Andrew J. Roger

Wanda Danilchuk

Marlena Dlutek

Jon Jerlstrom Hultqvist

Dayana Salas

Segio Munoz

Gregory Seaton

Dandan Zhao

Shelby Williams

Jeremy Wideman

Former Roger Lab Members

Sebastian Hess, Post Doctoral Fellow

To access Sebastian's web page, click here

During my doctoral studies in Cologne (Germany), I investigated the structure, life histories and evolution of diverse, poorly known protists that feed specifically on freshwater microalgae. Besides my studies about vampyrellid amoebae (Vampyrellida, Rhizaria), I discovered and characterised the Viridiraptoridae, a family of cercozoan amoeboflagellates, which perforate algal cells to feed on protoplast material. I came to Halifax as a postdoctoral research fellow to study the molecular mechanisms involved in this complex feeding behaviour, in particular cell wall degrading enzymes and actin-binding proteins. These proteins will be explored in the species Orciraptor agilis (Viridiraptoridae) during different life history stages using a comparative transcriptomic approach and a selection of biochemical methods. For this project, I work together with Andrew Roger (Department of Biochemistry and Molecular Biology) and Alastair Simpson (Department of Biology).

Other interests include:

  • structure, evolution and systematics of vampyrellid amoebae (Vampyrellida, Cercozoa)
  • cytoskeleton architecture and ultrastructure of protists
  • endosymbiotic bacteria (e.g. Rickettsiales) in protists

    Research papers:

  • Hess S. (2017). Hunting for agile prey: trophic specialisation in leptophryid amoebae (Vampyrellida, Rhizaria) revealed by two novel predators of planktonic algae. FEMS Microbiology Ecology 93(9): 1-12.
  • Hess S. (2017) Description of Hyalodiscus flabellus sp. nov. (Vampyrellida, Rhizaria) and identification of its bacterial endosymbiont, "Candidatus Megaira polyxenophila" (Rickettsiales, Alphaproteobacteria). Protist 168(1): 109-133.
  • Bush A. & Hess S. (2017). The cytoskeleton architecture of algivorous protoplast feeders (Viridiraptoridae, Rhizaria) indicates actin–guided perforation of prey cell walls. Protist 168(1): 12-31.
  • Hess S., Suthaus A., Melkonian M. (2016). “Candidatus Finniella” (Rickettsiales, Alphaproteobacteria), novel endosymbionts of viridiraptorid amoeboflagellates (Cercozoa, Rhizaria). Applied and Environmental Microbiology. 82: 659-670. doi:10.1128/AEM.02680-15.
  • Hess S. (2015). Algivorous freshwater protists of the phylum Cercozoa (Rhizaria) – structure, life histories and evolution. Dissertation University of Cologne, Verlag Dr. Hut, München, ISBN 9783843921688.
  • Hess S. & Melkonian M. (2014). Ultrastructure of the algivorous amoeboflagellate Viridiraptor invadens (Glissomonadida, Cercozoa).Protist 165(5): 605-635.
  • Hess S. & Melkonian M. (2013). The mystery of clade X: Orciraptor gen. nov. and Viridiraptor gen. nov. are highly specialised, algivorous amoeboflagellates (Glissomonadida, Cercozoa). Protist 164(5): 706-747.
  • Hess S., Sausen N., Melkonian M. (2013). Shedding light on vampires: the phylogeny of vampyrellid amoebae revisited. PloS one, 7(2): e31165.
  • Foissner W., Hess S., Al-Rasheid K. (2009). Two vicariant Semispathidium species from tropical Africa and central Europe: S. fraterculum nov. spec. and S. pulchrum nov. spec. (Ciliophora, Haptorida). European Journal of Protistology 46(1): 61-73.
  • Hess S., Frahm J.-P., Theisen I. (2005).Evidence of zoophagy in a second liverwort species, Pleurozia purpurea. The Bryologist 108(2): 212-218.

    You can reach Sebastian at:

    Work Phone: (+1) 902-494-2881
    Fax: (+1) 902-494-1355
    E-mail: shess{at}dal{dot}ca