Cooperative Motility, Force Generation and Mechanosensing in a Foraging Non-Photosynthetic Diatom

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.03.27.533254v1?rss=1 Authors: Zheng, P., Kumadaki, K., Quek, C., Lim, Z. H., Ashenafi, Y., Yip, Z. T., Newby, J., Alverson, A. J., Jedd, G. Abstract: Diatoms are ancestrally photosynthetic microalgae. However, some underwent a major evolutionary transition, losing photosynthesis to become obligate heterotrophs. The molecular and physiological basis for this transition is unclear. Here, we isolate and characterize new strains of non-photosynthetic diatoms from the coastal waters of Singapore. These diatoms occupy diverse ecological niches and display glucose-mediated catabolite repression, a classical feature of bacterial and fungal heterotrophs. Live-cell imaging reveals deposition of secreted extracellular polymeric substance (EPS). Diatoms moving on pre-existing EPS trails (runners) move faster than those laying new trails (blazers). This leads to cell-to-cell coupling where runners can push blazers to make them move faster. Calibrated micropipettes measure substantial single cell pushing forces, which are consistent with high-order myosin motor cooperativity. Collisions that impede forward motion induce reversal, revealing navigation-related force sensing. Together, these data identify aspects of metabolism and motility that are likely to facilitate and underpin the transition to obligate heterotrophy. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC