Scientists have recently unveiled the surprising intricacy of circadian clocks in bacteria, specifically in the soil bacterium Bacillus subtilis. Over a tenth of all living organisms are made up of bacteria, and it has only lately been recognized that these soil bacteria, akin to humans, contain internal timing mechanisms. These circadian rhythms synchronize the bacteria’s activities with Earth’s daily 24-hour cycle.
The recent study sheds light on the profound complexity of these bacterial timekeepers, opening doors to a new, thrilling phase of research. This exploration may lead to various applications, such as the precise timing of antibiotic use and the intelligent bioengineering of gut and soil microorganisms.
The discovery was made by an international partnership, including Ludwig Maximillian University Munich, The John Innes Centre, The Technical University of Denmark, and Leiden University. They identified the circadian clock’s activity in Bacillus subtilis by investigating gene expression.
Dr. Francesca Sartor, the lead author, described how the bacterial circadian clock regulates various genes and behaviors, whereas Professor Antony Dodd expressed astonishment at the complexity of the clock in such a simple organism with a small genome.
Previous efforts from this group had established the existence of a circadian clock in a lab-based strain of this bacterium using bioluminescence as a guide. It was the first observation of circadian rhythms in Bacillus subtilis.
Professor Martha Merrow, the senior author, emphasized the wide prevalence of circadian clocks in Bacillus subtilis, suggesting the possibility of leveraging this knowledge for health improvement and sustainable food or biotechnology production.
This new research is noteworthy in many aspects. It shows that the clocks exist in strains found in natural surroundings, suggesting they could be common in this bacteria. The study also unveils nuanced responses found in the circadian clocks of various organisms.
The findings open up possibilities in biotechnology, human health, and plant science, such as enhanced industrial microbiology applications, insights into microbiome formation, and antibiotic efficacy at different times. The information may also benefit crop protection, as Bacillus subtilis aids in nutrient exchange, plant growth, and defense against harmful microbes.
The researchers are working on Bacillus subtilis as a standard model for studying bacterial circadian clocks and investigating the genes that constitute the clock mechanism and how the clock relies on multicellular organization.
Circadian clocks are innate timers that help organisms adapt their physiological and metabolic functions to 24-hour environmental changes, like alterations in light, temperature, or predator behavior.
Professor Ákos T. Kovács commented on the complexity of the circadian clock in Bacillus subtilis, comparing it to the more intricate circadian systems in complex organisms like mammals, flies, and plants, reflecting the universal rules of molecular biology.
The reference to the study is “The circadian clock of the bacterium B. subtilis evokes properties of complex, multicellular circadian systems” by Francesca Sartor et al., published in Science Advances on August 4, 2023, with DOI: 10.1126/sciadv.adh1308.
