Nagwani, Amit KumarBudka, AnnaŁacka, AgnieszkaKaczmarek, ŁukaszKmita, HannaCesari, Michele2024-06-172024-06-172023-09-08Frontiers in Physiology 14 (2023): 1253483.https://hdl.handle.net/10593/27737Our data indicate that Δψ level could be a useful marker of the tardigrade P. experimentalis age. Moreover, the tardigrade sensitivity to HMF treatment including Δψ changes may also serve as the marker. Using an accurate marker of tardigrade age may contribute to an explanation of tardigrade aging. The obtained results also provide important data concerning age- and sex-related changes in mitochondrial functioning under extreme conditions. Similar to other animals, P. experimentalis responds to HMF treatment with Δψ decrease, but the decrease does not result in impaired survival as reflected by the animal’s physical activity although the activity was shortly and transiently attenuated after the longest HMF treatment. Thus, the long-term effects of the Δψ decrease on the tardigrade longevity and/or reproduction should be further studied to fully explain biological significance of HMF treatment. The observed relationship between the decrease in Δψ level and duration of HMF treatment suggests that HMF effect on mitochondria functionality increases over time. This observation is useful for creating models relevant to long-term space missions, where continuous exposure to HMF is a potential risk factor for different organisms, including humans. Nevertheless, the studied factors should also be considered in studies of HMF effect on other tardigrades species.Even for tardigrades, often called the toughest animals on Earth, a hypomagnetic field (HMF) is an extreme environment. However, studies on the effect of HMF on tardigrades and other invertebrates are scarce. Mitochondria play an important role in an organism’s response to extreme conditions. The effect of HMF on the mitochondrial inner membrane potential (Δψ), a well-known marker of mitochondria functionality, shows that mitochondria are very sensitive to HMF. To measure the HMF effect on Paramacrobiotus experimentalis, we calculated the tardigrade survival rate and Δψ level after HMF treatments of different durations. We also estimated the relationship between the age and sex of the tardigrade and the HMF effect. We observed age- and sex-related differences in Δψ and found that Δψ changes after HMF treatment were dependent on its duration as well as the animal’s age and sex. Furthermore, active P. experimentalis individuals displayed a high survival rate after HMF treatment. The data may contribute to the understanding of tardigrade aging and their resistance to extreme conditions including HMF, which in turn may be useful for future space explorations.en-USAttribution 4.0 Internationalinfo:eu-repo/semantics/articlehttps://doi.org/10.3389/fphys.2023.1253483