2027-L01 Defining the Role of Metals in Tardigrade Survival Under Environmental Extremes

Tardigrades are renowned for their extraordinary ability to survive environmental extremes including dehydration, freezing, ionising radiation, oxygen limitation and prolonged metabolic arrest. During cryptobiosis, metabolism becomes essentially undetectable, yet individuals can remain viable for years before resuming normal biological activity upon rehydration. Recent studies have identified unique protective proteins involved in DNA and cellular stabilisation, but the contribution of metals and metalloproteins to tardigrade stress tolerance remains almost entirely unexplored. This represents a major knowledge gap in our understanding of how life adapts to environmental extremes. 

A growing body of evidence suggests that metals such as manganese may play a crucial role in protecting cells against oxidative damage. In radiation-resistant bacteria such as Deinococcus radiodurans, accumulation of Mn(II)-containing complexes protects proteins from reactive oxygen species generated during irradiation and desiccation. Whether similar strategies exist in tardigrades is unknown. No systematic investigation has been undertaken to determine whether tardigrades possess novel metal-dependent antioxidant proteins that contribute to their remarkable resilience. 

This project will address two questions: (i) what metals accumulate in tardigrades during cryptobiosis and subsequent recovery, and (ii) do tardigrades possess previously unrecognised metal-dependent antioxidant proteins? 

The research will combine bioinorganic chemistry, advanced spectroscopy and imaging, and molecular biology. Tardigrades will be subjected to controlled environmental dehydration and rehydration cycles. Changes in elemental composition will be quantified using techniques such as ICP-MS, and spatial metal distributions investigated using X-ray fluorescence imaging. Complementary transcriptomic and comparative genomic analyses will identify metal transporters, antioxidant systems, and candidate metal-binding proteins whose expression changes during stress exposure. 

Candidate proteins will be produced using recombinant expression systems and characterised using UV-visible spectroscopy, electron paramagnetic resonance (EPR), X-ray absorption spectroscopy and metallomic techniques. Functional assays will determine their ability to bind metals and protect biomolecules under conditions relevant to desiccation and irradiation. 

The project will provide the first comprehensive description of metal utilisation in tardigrades and establish whether metal-centred antioxidant mechanisms contribute to survival under extreme conditions. By revealing previously unknown strategies for biological resilience, the research advances understandings of adaptation to environmental stress while identifying potential applications in biotechnology, conservation science, biopreservation and environmental resilience. 

Figure 1: Tardigrades are organisms that survive exposure to harsh environmental extremes, the ultimate microscopic survivors. Developing an understanding of how they are adapted to survive to extreme changes in environment may provide inspiration for how to cope with the effects of climate change.