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  • Most animals have an internal clock, a process that happens in our bodies telling us when to wake up and when to go to sleep.

  • You may be surprised to learn that many plants have a version of this body clock too, and now, it turns out, so do bacteria!

  • This concept of a biological clock is often called a circadian rhythm.

  • You may think of it just as those signals that make you sleepy at night and wake your body up in the morning,

  • but there are actually thousands of tiny clocks, controlling all kinds of biological pathways inside of us on timed cycles.

  • They're this beautiful, finely tuned dance of sensory information coming in, sparking a cascade of hormones and other signaling chemicals, turning the cogs of some very specific molecular machinery in our cells.

  • In humans, these are important to our health and mental processing, and in animals that have them, biological clocks help us adapt to our environment.

  • So, I guess it's not surprising that we see these rhythms in plants, too.

  • I mean organisms that photosynthesize also need to regulate their processes based on when the sun is out.

  • And get this, it's not just that organisms react to a stimulus like the sun rising.

  • Research shows that organisms like plants anticipate the rising of the sun, and continue cycling in their circadian rhythm even when deprived of that external cue, meaning that essentially, they can tell time.

  • And with this understanding, it also makes sense that tiny microbes called cyanobacteria, which photosynthesize, also have a circadian rhythm.

  • But what's a little weirder is that just regular old bacteria, chilling in the soil or on our bodies or in your fridge, also have an internal clock!

  • Now, you might be saying at this point, "Okay, that's interesting, but like, why should we really care?"

  • And I see where you're coming from, but bacteria are everywhere.

  • We can't even see them with our naked eye and yet they make up roughly 15% of all the biomass on this planet.

  • They're essential not only to human health but to the health of the crops we grow and to the creation of industrial products.

  • We pretty much couldn't do anything without them. So knowing more about how they tick is pretty important!

  • An international team of researchers recently published a study on this little guy, Bacillus subtilis.

  • They used a bioluminescent compound to track the activity of certain genes, and they found that levels of expression for these genes cycled up and down, aligning with a 24-hour cycle with 12 hours of light and 12 hours of dark.

  • See, B. subtilis is light sensitive. It has photoreceptors that allow it to react to light, how cool is that?

  • So it cycles the expression of some of its genes based on the input it‘s receiving.

  • But the researchers also found that like with plants, they could take away the stimulus, the light, and the bacteria still performed the same cycle. So, these bacteria can tell time, you guys!

  • This is the first time we've ever seen something like this in a non-photosynthetic bacterium.

  • The research team actually observed a similar pattern in response to daily temperature changes, with expression of other genes also fluctuating with temperature shifts throughout the day.

  • But again, you might be saying, "What do we do with this information?"

  • Well, if bacterial behavior does indeed shift and cycle in response to the environment, and certain bacteria have certain set rhythms, this might affect how we interact with those bacteria.

  • Like maybe giving an antibacterial treatment at a certain time of day would be more effective than at another time because of the bacteria's circadian rhythm.

  • In another example, Bacillus subtilis, the bacteria looked at in this study, is often used in crop soil to promote plant growth, so maybe learning more about its cycles could help us use it to even greater effect in agriculture.

  • And maybe an industrial production process, like the one that uses the bacterium E. coli to produce insulin, could also be optimized to use the organism's daily clock.

  • More research into all of these ideas, as well as exploring the potential rhythms of other bacteria, could give us the answers we need to better navigate and interact with our increasingly important microbial world.

  • And I, for one, am so excited to find out more about what makes them tick.

  • Are you surprised by this discovery? Do you have questions about another bacterial innovation you want us to cover?

  • Let us know down in the comments below.

  • You can check out another video about amazing bacterial behavior here, and make sure you subscribe to Seeker to keep up with all your creepy crawly behavioral news.

  • As always, thank you so much for watching, and I'll see you in the next one.

Most animals have an internal clock, a process that happens in our bodies telling us when to wake up and when to go to sleep.

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