PNAS Cover July 2023
Description: Digital illustration of Lacrymaria olor feeding behavior for the cover of PNAS. Pictured is an overlay of dynamic cell shapes in the single-celled ciliate Lacrymaria olor as the organism hunts for prey. Deepak Krishnamurthy and Manu Prakash explored the physics of hunting in L. olor, which has a slender, cilia-covered neck without neurons. The authors modeled an active filament that undergoes time-varying sequences of active stresses, producing filament shape dynamics correlated with cellular behaviors. Under different conditions, the filaments produce both periodic and aperiodic behaviors, the latter resulting from chaotic dynamics. According to the authors, the findings may help design and program robots based on active filament systems. See the article by Krishnamurthy and Prakash, e2304981120.