Can bacteria perceive the passage of time?

The circadian rhythms are vital processes for the functioning of our body. Thanks to them, our body knows when to sleep, eat, go to the bathroom, etc. In addition, it helps us adapt to our environment. Now, the possibility arises that living beings such as bacteria can also use them to be able to perceive the passage of time.

Research that has suggested that bacteria have their own circadian cycles was published in Science Advances. This was born from the hand of researchers Zheng Eelderink-Chen, Jasper Bosman, Francesca Sartor, Antony N. Dodd, Ákos T. Kovács, and Martha Merrow.

Currently, we have been able to understand a little more about bacteria - which correspond to 12% of the planet's biomass. For example, we know that some are so resistant that they can survive even in space; We have also seen how others can "breathe out" electricity and that, in general, most share the same size, despite all their other differences.

However, despite all the above, there are still many secrets that these little living beings keep for us.

Bacteria do have circadian cycles to perceive the passage of time

Until recently, the only evidence supporting the presence of circadian rhythms in bacteria was directly related to those that were photosynthetic. Indeed, the cells that regulate circadian cycles not only maintain a rhythm but can also adapt to external changes in elements such as light and temperature.

For this reason, it is not unusual to find them in photosynthetic bacteria as an additional element. However, the new study, based specifically on the bacterium Bacillus subtilis, has at least found that a non-photosynthetic specimen also has its own circadian cycles. For this case, the researchers paid special attention to the ytvA gene and the KinC enzyme.

Adaptive cycles

For their experiment, the researchers first measured the activity of the gene and its enzyme with different changes of light every 12 hours. It was then possible to notice that the ytvA gene cyclically changed its processes, according to the amount of light in the environment. But, if it was removed, the cycles were maintained even in total darkness.

With this, the first evidence of the existence of circadian rhythms that help bacteria perceives the passage of time was marked. Since if the gene did not build a cycle, but reacted automatically to light, then in the conditions of total darkness it should not have been activated.

The researchers then ran a similar test, but with changes in temperature. Here both ytvA and KinC reacted to stimuli by adapting to new environmental changes over the course of a few days.

However, if the temperature changes were suspended, the cycles could gradually return to their original values. So the authors were able to confirm again the existence of patterns similar to circadian rhythms within these non-photosynthetic bacteria.

And what's next?

With this new knowledge, the researchers assure that a new door has been opened for the bacteriological study and the development of circadian cycles. At the moment, we know that these are there and that they help bacteria to perceive the passage of time, in addition to adapting to changes in their environment.

However, the truth is that it is not yet very clear which processes favor these cycles within bacteria. Likewise, it is still an unsolved question of why they developed these rhythms in the first place, and how much of an evolutionary advantage they give them.

Reference: A circadian clock in a non-photosynthetic prokaryote