ÌÇÐÄvlogÃÛÌÒ

‘Research into bacterial defence systems is currently one of the most dynamic areas in molecular biology. We are competing on the global stage – either others will move ahead of us, or we will move ahead of them,’ said Dr Mindaugas Zaremba, Research Professor at the ÌÇÐÄvlogÃÛÌÒ Life Sciences Center. This October, at the MIT MISTI (Massachusetts Institute of Technology International Science and Technology Initiatives) conference in Lithuania, he will present the SPARDA prokaryotic defence system – a bacterial defence mechanism against viruses that has only in recent years become the focus of scientific study.

Bacteria and viruses: the molecular arms race

‘The interaction between bacteria and bacteriophages – the viruses that infect them – is an ongoing struggle. Much like in the global arena, there is a continuous arms race in the microscopic world: bacteriophages evolve new ways to overcome bacterial defence, while bacteria develop various mechanisms to counter them,’ explained Dr Zaremba.

Together with his research group, the VU biochemist investigates this perpetual conflict at the molecular level: ‘Bacteriophages inject their genetic material into bacterial cells, take over their resources, replicate, and ultimately destroy the host. From a single infected cell, dozens and sometimes even hundreds of new phage particles can spread and attack other bacteria. The bacterial response is no less ingenious. Over the course of evolution, bacteria have developed hundreds of different defence systems capable of recognising and neutralising an invader. Yet the battle never ends: phages adapt, and bacteria respond with new strategies.’

A system distinguished by suicidal defence to protect the population

Nearly 200 distinct bacterial defence systems have been described, but most remain poorly understood. Only a few are widely known, such as restriction-modification systems or CRISPR–Cas, which revolutionised gene engineering and genome editing. One of the newly studied systems is SPARDA, which forms the focus of Dr Zaremba’s work.

‘The SPARDA system stands out because, during infection, it cleaves not only the viral genome but also the DNA of the host bacterium. This may look paradoxical, but by destroying itself, the cell prevents further spread of infection. This altruistic process is known as abortive infection – a suicidal defence strategy where the loss of an individual protects the population,’ noted Dr Zaremba.

Another feature of SPARDA is that, upon activation, it forms filaments of long helical-like protein structures. Recent discoveries of new bacterial defence systems and studies of their mechanisms of action have revealed the emerging trend of supramolecular assemblies (including filaments) in bacterial immunity. Such findings expand our understanding of microbial life and may also provide tools for biotechnology and medicine, from protecting fermentation processes or fighting against infections to developing new diagnostic methods.

From the food industry to medical innovation

Although the research is still in the initial stages of development, it may later contribute to applied solutions. According to Dr Zaremba, in the food industry, this knowledge could help protect bacteria used in cheese or yoghurt fermentation from viral losses.

‘In medicine, bacteriophages are increasingly considered an alternative to antibiotics, particularly against antibiotic-resistant infections. To make phage therapy effective, we need to understand the defence systems that bacteria use. In biotechnology, SPARDA shows potential for nucleic acid diagnostics – future tests based on this system could enable rapid identification of pathogens,’ he clarified.

International scientific dialogue

On 9 October, Dr Zaremba will present his work at the international MIT MISTI conference in Lithuania. His presentation, ‘Mechanism of the Action of the SPARDA Prokaryotic Defence System’, will be part of a programme covering topics ranging from life sciences to artificial intelligence.

Dr Zaremba views the opportunity to speak at MIT MISTI as valuable recognition and a chance to expand collaborations: ‘MIT is a global leader in both fundamental and applied research. Working with them holds enormous potential,’ he acknowledged. Notably, Dr Zaremba and his colleagues have already successfully collaborated with Prof. Laub at MIT, working together on studies of newly discovered bacterial defence systems.
He also emphasises that students and early-career researchers have been involved in these projects: ‘They not only contributed to the work but also gained skills important for their future – whether in academia, start-ups, industry, or other innovative fields. The SPARDA system remains at an early stage of its exploration, yet it has already garnered international attention. This strengthens Lithuania’s role in the life sciences and helps foster a new generation of researchers whose engagement in the global arena also brings significant benefits to society.’