Nav: Home

Highly safe biocontainment strategy hopes to encourage greater use of GMOs

June 07, 2017

Use of genetically modified organisms (GMOs) - microorganisms not found in the natural world but developed in labs for their beneficial characteristics - is a contentious issue.

For while GMOs could greatly improve society in numerous ways - e.g. attacking diseased cells, digesting pollution, or increasing food production - their use is heavily restricted by decades-old legislation, for fear of what might happen should they escape into the environment.

For researchers, aware of their potential, it is important to develop safety strategies to convince legislators they are safe for release.

For this reason Hiroshima University's Professor Ryuichi Hirota and Professor Akio Kuroda, have developed an extra safe phosphite-based biocontainment strategy.

Biocontainment strategies - methods used to prevent GMO escape or proliferation beyond their required use, typically employ one of two forms.

One is "suicide switch" where released GMOs die off independently after a given time. The other is "nutrient requirement", where GMOs are designed to expire on removal of a nutrient source.

The control method for the new genetically modified E. coli strain of bacteria employs the latter, and its simple practicality could prove a real game changer.

It relies on the fact that all living things require phosphorous for a vast array of life-determining processes including energy storage, DNA production, and cell signal-transduction. The overwhelming majority of bacteria, source phosphorous from the naturally occurring nutrient phosphate.

However, bacteria are renowned for their ability to obtain energy from seemingly implausible sources and the researchers at HU found one type, Ralstonia sp. Strain 4506, capable of utilizing non-naturally occurring phosphite instead - throwing up exciting possibilities.

As Phosphite, a waste by-product from the metal plating industry, does not occur in the natural world, scientists can easily control its availability and determine potential GMO proliferation.

Strain 4506's phosphite-digesting enzyme was thus isolated and introduced into E. coli bacteria, which due to its versatility is considered the poster boy of the GMO world. Genetic editing also saw a phosphite specific "transporter" created to allow this nutrients intake.

But while this modified E. coli, now with phosphite munching capabilities, was quite the novelty in the HU lab, there was still a major hurdle to overcome - it still possessed innate phosphate transport mechanisms intact, and could equally survive on non-naturally occurring phosphite or naturally occurring phosphate. It could easily escape and thrive.

As E. coli has seven phosphate transporters - pumps for transferring phosphate from outside the cells membrane to inside, Professors Hirota and Kuroda set about shutting them down using genetic editing.

When the resulting GMO was tested the results were outstanding. It proliferated in a phosphite medium, and didn't grow at all when exposed only to phosphate.

Further, when thriving populations were later deprived of their phosphite-hit, their numbers tumbled over a two week period to zero - thus fulfilling the criteria for "nutrition requirement" biocontainment.

However, what the scientists discovered next astounded them. Even when this new GMO was successfully and continuously cultured on phosphite, its population nevertheless still began plummeting after two weeks.

Baffled, the HU researchers are investigating but there is a possibility that this strategy possesses "suicide switch" characteristics on top of "nutrient requirement".

Whatever the reason, an extremely safe and practical biocontainment strategy has been born. Requiring just nine simple gene edits, in naturally occurring organisms, and based on phosphite - a readily available industrial waste product; it is extremely cost and time effective. Additionally, its simplicity means it can be adapted for other microorganisms, making it highly versatile.

These traits contrast with previous biocontainment strategies involving synthetic organisms and energy sources, requiring hundreds of gene edits, awful lots of money and time, and which are so specialized as to make them impractical.

It is hoped this new strategy will grab the attention of relevant government agencies, and convince them to bring 1980s laws in line with 21st Century advancements. We can then get GMOs safely out of the lab for the betterment of society!
-end-


Hiroshima University

Related Bacteria Articles:

Conducting shell for bacteria
Under anaerobic conditions, certain bacteria can produce electricity. This behavior can be exploited in microbial fuel cells, with a special focus on wastewater treatment schemes.
Controlling bacteria's necessary evil
Until now, scientists have only had a murky understanding of how these relationships arise.
Bacteria take a deadly risk to survive
Bacteria need mutations -- changes in their DNA code -- to survive under difficult circumstances.
How bacteria hunt other bacteria
A bacterial species that hunts other bacteria has attracted interest as a potential antibiotic, but exactly how this predator tracks down its prey has not been clear.
Chlamydia: How bacteria take over control
To survive in human cells, chlamydiae have a lot of tricks in store.
Stress may protect -- at least in bacteria
Antibiotics harm bacteria and stress them. Trimethoprim, an antibiotic, inhibits the growth of the bacterium Escherichia coli and induces a stress response.
'Pulling' bacteria out of blood
Magnets instead of antibiotics could provide a possible new treatment method for blood infection.
New findings detail how beneficial bacteria in the nose suppress pathogenic bacteria
Staphylococcus aureus is a common colonizer of the human body.
Understanding your bacteria
New insight into bacterial cell division could lead to advancements in the fight against harmful bacteria.
Bacteria are individualists
Cells respond differently to lack of nutrients.

Related Bacteria Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...