Like clockwork, the daily rhythm of B. subtilis

– Aug. 21, 2023

People have a biological 24-hour clock, also known as the day-night rhythm or circadian rhythm. Most people sleep at night and are awake during the day. But you can also see it in our body temperature and metabolism. Did you know that some bacteria, like Bacillus subtilis, also have an internal clock? These tiny organisms are often thought of as simple, but they turn out to be more complex than we thought.

Surprisingly complex

More than 10% of all living things on Earth are bacteria. Bacteria are often seen as simple because of their basic cell structure. But scientists have discovered that some bacteria living in the soil have an inner clock. Bacillus subtilis, a bacteria found worldwide, follows the 24-hour rhythm of the Earth.

Day and night rhythm

When you track this bacterium throughout the day, you can see that its gene expression changes. During the day and night, the bacterium uses different genetic information. Researchers discovered this by modifying a bacterium they found in the wild. They made the bacteria light up when specific genes were used, so they could see which genes are active at different times. This revealed that the bacterium adjusts its metabolism during the 24-hour cycle.

Teaming up with bacteria

Until now, these kinds of day-night rhythms were mostly known in plants and animals. It's intriguing that even simple bacteria have this ability. This discovery opens doors to improve our collaboration with bacteria. For instance, Bacillus subtilis is used by farmers to convert nutrients, fight pathogens, and promote plant growth. By providing bacteria with the right substances at the right times, this could be optimized.

This discovery shows that there is still much to uncover about the hidden world around us.

Author: Eline van Bloois