Study reveals how bacteria use ancient self-repair mechanisms

A new study led by scientists at UNSW Sydney reveals how nature’s oldest wheel, found in bacteria, can repair itself during difficult times.

The results published today in scientific advancesshow how the flagellum — the ancient motor that powers bacteria’s ability to swim — can also help these tiny organisms adapt to conditions in which their motility is compromised.

Bacteria are one of the oldest living organisms on earth. They are tiny single-celled organisms found in every habitat, including the human body — where there are more bacterial cells than human cells.

Being able to swim is crucial to how bacteria survive and spread. However, little is known about how the engines that power their movement help organisms adapt to hostile environments.

The researchers from the School of Biotechnology and Biomolecular Sciences are the first in the world to use CRISPR gene-editing technology to alter a flagellar motor. They used synthetic biology techniques to engineer a sodium engine into the genome to create a sodium-powered swimming bacterium. They then tested and tracked the bacteria’s ability to adapt when the environment was low in sodium.

Sodium is an ion, meaning it carries a charge. It is this charge that drives the flagellar motor through stators or ion channels.

The team found that the stators were able to quickly self-repair the flagellar motor and restore motion. These findings could lead to new advances in the fields of biology and medicine.

“We have shown that environmental changes can cause ion channels to respond rapidly,” said the publication’s lead author, Dr. Pietro Ridone.

“So the CRISPR edits also come back quickly, and the flagellar motor develops and then regulates itself,” said Dr. ridone.

“That we immediately saw mutations directly on the stators is surprising and also inspires many of our future research plans in this area.”

The power of the molecular machinery

The human body contains around 10,000 different types of molecular machines that power a range of biological functions from energy conversion to movement.

The technology of a bacterial motor far surpasses what humans can synthesize at the nanoscale. One-millionth the size of a grain of sand, it can self-assemble and rotate up to five times faster than a Formula 1 engine.

“The engine that powers bacterial swimming is a marvel of nanotechnology,” said Associate Professor Matthew Baker, a co-author of the paper. “It’s the absolute flagship for ancient and very sophisticated molecular machines.”

A/Prof. Baker said the study’s results could help us better understand, in mechanistic detail, the origin of molecular motors – how they came together and how they adapt.

“These ancient parts are a powerful system for studying evolution in general and the origins and development of agility.”

A/Prof. Baker says the results will shed light on how synthetic biology can help create new molecular motors. The results may also have application in understanding antimicrobial resistance and disease virulence.

“By shedding more light on the ancient history of life, we gain knowledge to create tools that can help improve our future,” A/Prof. said baker. “It can also lead us to insights into how bacteria might adapt under future climate change scenarios.”