| Summary: | Most organisms die when confronting extreme desiccation regimes, as observed in severe and prolonged droughts. However, some organisms are able to withstand such conditions by entering into a unique state of true suspended animation known as anhydrobiosis. Notably, anhydrobiosis also renders the organism tolerant to several other physical stresses such as extremes of temperature, pressure and radiation. Anhydrobiosis-based technologies are promising strategies to preserve crop plants as well as organs for transplant. In order to understand the relation between anhydrobiosis and tolerance to physical stresses, we submitted the anhydrobiotic nematode Panagrolaimus superbus to diverse abiotic stresses when alive (hydrated) and in anhydrobiosis (desiccated). Remarkably, our data revealed that hydrated P. superbus naturally displays considerable tolerance to ultra-low temperature (-196 °C), X-radiation (500 Gy) and ultracentrifugation (400,000xg) in the tested conditions. More importantly, anhydrobiosis enhances nematode tolerance to ultra-low and high temperatures (+100 °C), but not to X-radiation or ultracentrifugation. These findings may help explain the successful wide distribution of P. superbus on Earth, since extremes of temperature are the most common stresses confronted by this species. Finally, due to its intrinsic survival potential (hydrated or desiccated), our data evidence the potential of P. superbus as a model in astrobiology.
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