Circadian rhythms: As time glows by in bacteria
Carl Hirschie Johnson1

Topof page Abstract Populations of cells can exhibit remarkably precise and stable circadian oscillations. But can single cells achieve such precision in the absence of intercellular communication? For cyanobacteria, it seems so.

Have you ever heard of a bacterium with jet lag? The idea might seem absurd; 20 years ago, experts in the field would have thought so too.
Carl Hirschie Johnson is in the Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA.e-mail: Email:


Evidence of circadian rhythms in non-photosynthetic bacteria?
María I SorianoBegoña RoibásAna B García and Manuel Espinosa-Urgel

Examples of circadian rhythms have been described in eukaryotic organisms and in photosynthetic bacteria, but direct proof of their existence in other prokaryotes is limited and has been largely ignored. The aim of this article is to review existing evidence and to present preliminary results that suggest that the heterotrophic bacterium Pseudomonas putida shows regular variations in its growth pattern synchronized with light/darkness cycles. We put forward the hypothesis that circadian regulation of certain processes can take place in non-photosynthetic prokaryotes and may represent an adaptative advantage in specific environments.

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