Solitary choanoflagellate dynamics and microconfined directed transport

J. SPARACINO; G L. MIÑO; A. J. BANCHIO; V. I. MARCONI

JOURNAL OF PHYSICS - D (APPLIED PHYSICS)

IOP PUBLISHING LTD

Lugar: Londres; Año: 2020 vol. 53 p. 50540301 - 50540311

0022-3727

In evolutionary biology, choanoflagellates are broadly investigated as the closest animalancestors. Under suitable environmental cues, choanoflagellate Salpingoeca rosetta candifferentiate into two types of solitary motile cells. Each group is recognized by its own strategyto swim and its morphology. Moreover, under nutrient limited conditions, S. rosetta experiencea haploid-to-diploid transition evidenced by the presence of gametes. It is challenging todetermine if there is a connection between the two types of swimming strategies and the maleand female gametes. Therefore a current interest is to isolate and concentrate the fast swimmingcells, for instance, using a microfluidic device. Following this aim we measured their body sizesand characterized their motilities. We determined that fast cells swim remarkably different fromslow cells and proposed a phenomenological model to reproduce the observed dynamics. Wesolved the Langevin dynamical equations of motion using experimental parameters forchoanoflagellates swimming in a confined flat microdevice divided by a wall of asymmetricobstacles. A systematic study of the directed transport efficiency was performed in order tooptimize the geometry of the obstacles wall. Numerical results showed that fastchoanoflagellates can be directed efficiently for a wide range of geometric parameters of theobstacles wall while slow cells are hardly directed independently of its geometry. The cleardifferences found in the rectification of fast and slow choanoflagellates suggest that an efficientmicro-sorter device could be designed for further applications in evolutionary biology.