Humble algae holds key to unlocking secrets of the human body clock

By Mark Waghorn via SWNS

Humble algae hold the key to unlocking the secrets of the human body clock, new research found.

The circadian rhythms of cyanobacteria are driven by a specific gene that has implications for insects, plants and even mammals, scientists said.

Unlocking them could help prevent diseases - and help drugs work better. Medications have been found to work better when administered at certain times of the day.

An out-of-sync body clock raises the risk of cancer, heart disease and type 2 diabetes - and can lead to obesity.

The marine organisms, also known as blue-green algae, have been around for billions of years. They helped fuel life on Earth by seeping oxygen into the atmosphere.

The cyanobacterial circadian clock is the simplest - yet it is still a very complex system. Japanese scientists focused on a protein called KaiC that regulates it.

Lead author Dr. Yoshihiko Furuike, of the National Institutes of Natural Sciences, Okazaki, said: "Proteins are composed of a vast number of atoms.

"It is not easy to understand the mechanisms of their complicated but ordered functions. We need to trace the structural changes of proteins patiently."

The team studied the atomic structures of the protein by screening thousands of crystallisation conditions.

It enabled them to cover the overall phosphorylation cycle - where a phosphate is transferred to the protein.

It cooperates with another reaction cycle, ATP hydrolysis, which is the energy consuming events determining the clock speed.

The system works like two gears for the cell activity. The researchers crystallised KaiC in eight distinct states. The coupling drives the clock.

The gene rhythmically activates and inactivates the reaction cycles autonomously to regulate assembly states of other clock-related proteins.

In future, the team might use structural biology to reveal the atomic mechanisms of acceleration and deceleration of the gear rotations.

Dr. Furuike said: "Our goal is to see all cyanobacterial clock proteins during the oscillation at an atomic level and to describe the moment the ordered rhythm arises from chaotic atomic dynamics."

The work described in Science Advances can serve as a research tool, improving understanding of the mechanisms of the circadian clock cycle.

Looking ahead, the researchers see the findings having wider applications. Mammals, insects, plants and bacteria all have their own clock proteins with distinct sequences and structures.

Dr. Furuike added: "However, the logic behind the relationship between KaiC dynamics and clock functions can be applied to other studies on various organisms."

Cyanobactera changed the planet forever, diversifying to cope with the rise of oxygen. Around 2.5 billion million years ago, young Earth was unrecognizable.

No ozone layer existed and there was no oxygen to breathe . Instead, the planet was dominated by microbes.

Today, cyanobacteria are widespread throughout the ocean, but then they were mostly restricted to freshwater and land.

They are the only bacteria capable of oxygenic photosynthesis, a process also used by plants to convert carbon dioxide into oxygen using sunlight.

They have an extensive fossil record. The oldest are from Archaean rocks of western Australia - dating back 3.5 billion years. The oldest rocks are only 300,000 years older.