We all operate with an internal clock. It is regulated by what researchers call the circadian rhythm. This rhythm controls virtually all the processes that take place in our body. It influences, for example, when we go to bed and when we wake up. The circadian rhythm also plays a role in the functioning of our metabolism and our cognitive process.
The internal clock imposes a 24 hour cycle on our organism. This phenomenon is not unique to human beings. It also occurs in animals, plants and some fungi. However, the researchers struggled to determine whether this process also occurs in all bacteria. They have tried to answer this question for years.
Recently, a team of scientists conducted a study that shed light on this issue.
Non-photosynthetic bacteria regulated by a circadian rhythm
Previous research has found that photosynthetic bacteria, that is, bacteria that use light to generate energy, have an internal clock. The researchers wanted to know if this was also the case for non-photosynthetic bacteria. To do this, they used Bacillus subtilis, a bacterium that is found in the soil or in the gastrointestinal tract of animals and humans.
They announced through their study that this bacterium also had an internal clock.
“We discovered for the first time that non-photosynthetic bacteria are able to tell the time. They adapt their molecular function to the time of the day based on the light cycle or the temperature of the environment, ” explains chronobiologist Martha Merrow of Ludwig Maximilian University in Munich.
Bacteria that act according to external conditions
Even though Bacillus subtilis are not photosynthetic, they remain sensitive to light. Thanks to their photoreceptors, the researchers were able to observe how their genes work when they are under different conditions. To begin with, they placed these bacteria in a very dark environment for 12 hours.
Then they were exposed for 12 hours to light. During this experiment, the researchers observed an increase in activity in a gene called ytvA when the bacteria were in the dark. This activity then decreased when the bacteria were in the light.
According to the researchers, this proves that the activities of non-photosynthetic bacteria are indeed regulated by a circadian rhythm.