A circadian clock in a nonphotosynthetic prokaryote.

Eelderink-Chen, Zheng; Bosman, Jasper; Sartor, Francesca; Dodd, Antony N; Kovács, Ákos T; Merrow, Martha · Sci Adv · 2021

basic_science · Level V

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Abstract

Circadian clocks create a 24-hour temporal structure, which allows organisms to occupy a niche formed by time rather than space. They are pervasive throughout nature, yet they remain unexpectedly unexplored and uncharacterized in nonphotosynthetic bacteria. Here, we identify in <i>Bacillus subtilis</i> circadian rhythms sharing the canonical properties of circadian clocks: free-running period, entrainment, and temperature compensation. We show that gene expression in <i>B. subtilis</i> can be synchronized in 24-hour light or temperature cycles and exhibit phase-specific characteristics of entrainment. Upon release to constant dark and temperature conditions, bacterial biofilm populations have temperature-compensated free-running oscillations with a period close to 24 hours. Our work opens the field of circadian clocks in the free-living, nonphotosynthetic prokaryotes, bringing considerable potential for impact upon biomedicine, ecology, and industrial processes.