Thursday, 04 January 2024
A decades-old mystery of how natural antimicrobial predatory bacteria are able to recognise and kill other bacteria may have been solved, according to new research.
In a study published today (4 January) in Nature Microbiology, researchers from the University of Nottingham and the University of Birmingham have discovered how natural antimicrobial predatory bacteria, called Bdellovibrio bacterivorous, produce fibre-like proteins on their surface to ensnare prey.
This discovery may enable scientists to use these predators to target and kill problematic bacteria that cause issues in healthcare, food spoilage and the environment.
The research was funded by the Wellcome Trust Investigator in Science Award (209437/Z/17/Z).
Professor of Structural Biology at the University of Birmingham, Andrew Lovering said: “Since the 1960s Bdellovibrio bacterivorous has been known to hunt and kill other bacteria by entering the target cells and eating them from the inside before later bursting out. The question that had stumped scientists was ‘how do these cells make a firm attachment when we know how varied their bacterial targets are?’”
Professor Lovering and Professor Liz Sockett, from the School of Life Sciences at the University of Nottingham, have been collaborating in this field for almost 15 years. The breakthrough came when Sam Greenwood an undergraduate student, and Asmaa Al-Bayati, a PhD student in the Sockett lab, discovered that the Bdellovibrio predators lay down a sturdy vesicle (a “pinched-off” part of the predator cell envelope) when invading their prey.
Professor Liz Sockett explained: “The vesicle creates a kind of airlock or keyhole allowing Bdellovibrio entry into the prey cell. We were then able to isolate this vesicle from the dead prey, which is a first in this field. The vesicle was analysed to reveal the tools used during the preceding event of predator/prey contact. We thought of it as a bit like a locksmith leaving the pick, or key, as evidence, in the keyhole.
Professor Liz Sockett. School of Life Sciences, University of Nottingham
By looking at the vesicle contents, we discovered that because Bdellovibrio doesn’t know which bacteria it will meet, it deploys a range of similar prey recognition molecules on its surface, creating lots of different ‘keys’ to ‘unlock’ lots of different types of prey.”
The researchers then undertook an individual analysis of the molecules, demonstrating that they form long fibres, approximately ten times longer than common globular proteins. This allows them to operate at a distance and “feel” for prey in the vicinity.
In total, the labs counted 21 different fibres. Researchers Dr Simon Caulton, Dr Carey Lambert and Dr Jess Tyson worked on how they operated both at the cellular and molecular level. They were supported by fibre gene-engineering by Paul Radford and Rob Till. The team then began to attempt linking a particular fibre to a particular prey-surface molecule. Finding out which fibre matches which prey, could enable an engineering approach which sees bespoke predators targeting different types of bacteria.
Professor Lovering continued: “Because the predator strain we were looking at comes from the soil it has a wide killing range, making this identification of these fibre and prey pairs very difficult. However, on the fifth attempt to find the partners we discovered a chemical signature on the outside of prey bacteria that was a tight fit to the fibre tip. This is the first time a feature of Bdellovibrio has been matched to prey selection.”
Scientists in this field will now be able to use these discoveries to ask which fibre set is used by the different predators they study and potentially attribute these to specific prey. Improving understanding of these predator bacteria could enable their usage as antibiotics, to kill bacteria that degrade food, or ones which are harmful to the environment.
Professor Lovering concluded: “We know that these bacteria can be helpful, and by fully understanding how they operate and find their prey, it opens up a world of new discoveries and possibilities.”
Story credits
More information is available from Professor Liz Sockett at the University of Nottingham in the School of Life Sciences at liz.sockett@nottingham.ac.uk
Notes to editors:
About the University of Nottingham
Ranked 32 in Europe and 16th in the UK by the QS World University Rankings: Europe 2024, the University of Nottingham is a founding member of the Russell Group of research-intensive universities. Studying at the University of Nottingham is a life-changing experience, and we pride ourselves on unlocking the potential of our students. We have a pioneering spirit, expressed in the vision of our founder Sir Jesse Boot, which has seen us lead the way in establishing campuses in China and Malaysia - part of a globally connected network of education, research and industrial engagement.
Nottingham was crowned Sports University of the Year by The Times and Sunday Times Good University Guide 2024 – the third time it has been given the honour since 2018 – and by the Daily Mail University Guide 2024.
The university is among the best universities in the UK for the strength of our research, positioned seventh for research power in the UK according to REF 2021. The birthplace of discoveries such as MRI and ibuprofen, our innovations transform lives and tackle global problems such as sustainable food supplies, ending modern slavery, developing greener transport, and reducing reliance on fossil fuels.
The university is a major employer and industry partner - locally and globally - and our graduates are the second most targeted by the UK's top employers, according to The Graduate Market in 2022 report by High Fliers Research.
We lead the Universities for Nottingham initiative, in partnership with Nottingham Trent University, a pioneering collaboration between the city’s two world-class institutions to improve levels of prosperity, opportunity, sustainability, health and wellbeing for residents in the city and region we are proud to call home.
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