@article {65, title = {The biomechanical role of extra-axonemal structures in shaping the flagellar beat of Euglena gracilis}, journal = {eLife}, volume = {10:e58610}, year = {2021}, abstract = {

We propose and discuss a model for flagellar mechanics in Euglena gracilis. We show that the peculiar non-planar shapes of its beating flagellum, dubbed {\textquoteright}spinning lasso{\textquoteright}, arise from the mechanical interactions between two of its inner components, namely, the axoneme and the paraflagellar rod. The spontaneous shape of the axoneme and the resting shape of the paraflagellar rod are incompatible. Thus, the complex non-planar configurations of the coupled system emerge as the energetically optimal compromise between the two antagonistic components. The model is able to reproduce the experimentally observed flagellar beats and the characteristic geometric signature of spinning lasso, namely, traveling waves of torsion with alternating sign along the length of the flagellum.\ 

}, keywords = {Euglena gracilis, extra-axonemal structures, flagellar beat, flagellar mechanics, physics of living systems}, doi = {10.7554/eLife.58610}, author = {Giancarlo Cicconofri and Giovanni Noselli and Antonio De Simone} } @article {52, title = {Kinematics of flagellar swimming in Euglena gracilis: Helical trajectories and flagellar shapes}, journal = {Proceedings of the National Academy of Sciences of USA}, volume = {114}, year = {2017}, pages = {13085{\textendash}13090}, abstract = {

The flagellar swimming of euglenids, which are propelled by a single anterior flagellum, is characterized by a generalized helical motion. The 3D nature of this swimming motion, which lacks some of the symmetries enjoyed by more common model systems, and the complex flagellar beating shapes that power it make its quantitative description challenging. In this work, we provide a quantitative, 3D, highly resolved reconstruction of the swimming trajectories and flagellar shapes of specimens of Euglena gracilis. We achieved this task by using high-speed 2D image recordings taken with a conventional inverted microscope combined with a precise characterization of the helical motion of the cell body to lift the 2D data to 3D trajectories. The propulsion mechanism is discussed. Our results constitute a basis for future biophysical research on a relatively unexplored type of eukaryotic flagellar movement.\ 

}, keywords = {3D flagellum shapes, Euglena gracilis, helical trajectories, microscopy imaging, microswimmers}, doi = {10.1073/pnas.1708064114}, author = {Massimiliano Rossi and Giancarlo Cicconofri and Alfred Beran and Giovanni Noselli and Antonio DeSimone} }