Centrioles are cylindrical organelles that are essential in organising the microtubule skeleton of eukaryotic cells. In his thesis, Nikolai examined to what extent centriolar architecture is conserved throughout evolution. He did so using a variety of primitive eukaryotic organisms and a combination of cutting-edge techniques, hoping to delve deeper into how centrioles originate.

Nikolai purified centrioles from amoebae, green algae, paramecia, and human cells and looked at them by cryo-electron tomography and expansion microscopy. Cryo-electron tomography allows visualising frozen samples in their native state, without fixation, in a series of slices much like a CT scan. Expansion microscopy is a relatively recent innovation which improves resolution of conventional fluorescence microscopy by physically spacing molecules in a sample. Both methods allowed Nikolai unprecedent nanoscale glimpses into the intricate details of centriolar structure.

In his thesis, Nikolai revealed the structure of the cartwheel-containing proximal region of the centriole, and, in collaboration with his PhD colleague Maeva Le Guennec, a previously undescribed helix that stabilizes the centriole from within.

Nikolai Klena is currently an EMBO long-term fellow in the lab of Gaia Pigino at the Human Technopole in Milan, studying cilia structure and function.

The Arditi foundation annually rewards one doctoral thesis among PhD students of the Section of Biology, for its originality and scientific impact. More information about the prize can be found here.