Choanoflagellate Model Using Regularized Stokeslets and Segments

Choanoflagellates are the closest living relative to animals and act as both unicellular and colonial eukaryotes. Their morphology consists of an oblong cell body with a flagellum for movement and a collar composed of microvilli that are used to capture bacteria. To simulate their feeding behaviors, our current computer simulations calculate the inward flux of fluid to the collar and the choanoflagellate translational and rotational velocities given its prescribed flagellar movement. However, the method of regularized Stokeslets (MRS) requires using thousands of points to discretize a morphology of a single cell to match the simulated results with experimental data. Since a large portion of the discretized points is on the collar, the method of regularized segments (MRSE) can simplify the model. The idea is, along each microvillus, replacing a cluster of discretized MRS points with a regularized segment that has linearly distributed forces. In this project, we found an optimal number of regularized segments to drastically reduce total memory consumption and computation time. The simulated results from the mixed method of MRS and MRSE matched the experimental velocity data and the inward flux calculations of the original MRS model. We then extended this simplified model from one cell to two cells to quantify how their angles affect the outputs. With the reduced computational strain and memory usage due to the mixed method, we were able to study the feeding patterns of larger colonies that were impossible to simulate using the MRS method. In the future, we will be able to simulate various colony shapes to test the hypothesis that multicellular life forms do have advantageous feeding patterns.