Study Reveals Bacteria Can Tell Whether It Is Morning or Night

Category: Science/Environment


Unlocking Word Meanings

Read the following words/expressions found in today’s article.

  1. circadian rhythm / sɜrˈkeɪ di ən ˈrɪð əm / (n) – the daily 24-hour cycle of bodily processes in most living things

    You feel sleepy at night because of your circadian rhythm.

  2. synchronize / ˈsɪŋ krəˌnaɪz / (v) – to move, operate, or work at the same time

    I synchronized my watch with the clock at the station to make sure that I won’t be late for the train.

  3. luminous / ˈlu mə nəs / (adj) – capable of producing light

    Fireflies are luminous insects.

  4. constant / ˈkɒn stənt / (adj) – continuing without any change

    The constant noise from the construction site was making it hard to sleep.

  5. trait / treɪt / (n) – a characteristic or quality

    Children usually get their parents’ physical traits, including hair and eye color.


Read the text below.

A recent study has shown that bacteria can tell whether it is morning or night.

Complex organisms such as humans, animals, and plants have long been known to have an internal mechanism called a circadian rhythm, which is a natural body clock that is synchronized with the Earth’s 24-hour cycle. The new study presents a breakthrough finding that even simple bacteria also follow a circadian rhythm, which allows them to identify the time of day and synchronize their body functions with it.

The researchers found the mechanism in a type of bacteria found in the soil called Bacillus subtilis. The scientists wanted to see if changes in the bacteria’s surroundings would affect its body functions. To find out, they added a luminous enzyme to the bacteria that would let them see what was happening inside it.

For the experiment, the researchers placed the bacteria in constant darkness first. Then, they subjected it to alternating 12-hour cycles of light and darkness and compared their findings. They also observed the bacteria’s reaction to changes in the temperature of its surroundings.

The researchers found that the bacteria’s genetic activity depended on the amount of light and the temperature of its surroundings, which is a common trait among organisms that have circadian rhythms. Based on the experiment’s results, they concluded that bacteria can tell the time of day by using external cues around it.

According to the researchers, the study’s findings may be used to determine if time of day affects how bacteria can infect people and if it has any effect in anti-bacterial treatment. They may also be useful in improving processes that involve bacteria, such as producing laundry detergent and protecting crops.

Viewpoint Discussion

Enjoy a discussion with your tutor.

Discussion A

• Would you like to know if bacteria or other living things also have other complex characteristics (e.g. ability to understand language, ability to feel emotions)? Why?

• What do you think would happen if people found out that other non-human living things have human-like characteristics? Discuss.

Discussion B

• If you could add more hours to the day (e.g. 30 hours), would you? Why or why not?

• If you had to add more hours to the day, would you create a longer daytime, longer nighttime, or equal day and night? Why?