Abstract
Archaea have evolved to survive in some of the most extreme environments on earth. Life in extreme, nutrient-poor conditions gives the opportunity to probe fundamental energy limitations on movement and response to stimuli, two essential markers of living systems. Here we use three-dimensional holographic microscopy and computer simulations to reveal that halophilic archaea achieve chemotaxis with power requirements one hundred-fold lower than common eubacterial model systems. Their swimming direction is stabilised by their flagella (archaella), enhancing directional persistence in a manner similar to that displayed by eubacteria, albeit with a different motility apparatus. Our experiments and simulations reveal that the cells are capable of slow but deterministic chemotaxis up a chemical gradient, in a biased random walk at the thermodynamic limit.
Highlights
Archaea have evolved to survive in some of the most extreme environments on earth
They possess genetic components for chemotaxis analogous to those found in bacterial species[2,3], suggesting that their chemotactic strategies must be both highly refined, and potentially similar to the ‘run and tumble’ or ‘run and reverse’ behaviours seen in eubacteria
This is inconsistent with current understanding of how Brownian motion limits bacterial chemotaxis[5,6]
Summary
Archaea have evolved to survive in some of the most extreme environments on earth. Life in extreme, nutrient-poor conditions gives the opportunity to probe fundamental energy limitations on movement and response to stimuli, two essential markers of living systems. We show that halophilic archaea perform chemotaxis by modulating their run durations in response to a chemical gradient.
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