DNA damage in storage cells of anhydrobiotic tardigrades

Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade

“…Tardigrades accumulate extensive DNA double-strand breaks with prolonged desiccation and when exposed to high levels of radiation (6,18,19). A number of protein families involved in DNA repair have been expanded in tardigrades (Dataset S4), and this expansion is due to the acquisition of foreign DNA in many cases.…”

“…S6): When desiccated membranes are rehydrated, they become transiently leaky, making the uptake of large macromolecules possible (29), which has been exploited previously to introduce large nucleic acids and drugs into the cytoplasm of rehydrating anhydrobiotic cells (30)(31)(32). In addition, when tardigrades, rotifers, and other anhydrobionts desiccate, genomic double-stranded breakages and other damage are induced (19,33,34), and there appear to be robust mechanisms for repairing this damage (19,34). We speculate that desiccation and associated membrane leakiness and DNA breakages might predispose these animals to take up and incorporate foreign material in their genomes (Fig.…”

Heat shock proteins in encysted and anhydrobiotic eutardigrades

“…Data collected till now on tardigrades suggest that Hsps may be involved in the biochemical mechanism utilized during rehydration rather than that connected to the stabilization of molecules in a dry state . During rehydration, Hsps could be involved in repairing molecular damages that occurred during the anhydrobiotic process as demonstrated by Neumann et al (2009) and Rebecchi et al (2009b). Similarly, in the moss Tortula ruralis [Hedw.]…”

Element analysis of the eutardigrades Richtersius coronifer and Milnesium cf. asiaticum using Particle Induced X-ray Emission (PIXE)

“…Documented tolerance to ionizing and UV radiation not only in desiccated tardigrades but also in active hydrated animals (May et al, 1964;Jönsson et al, 2005;Horikawa et al, 2006;Altiero et al, 2011) have raised the question if DNA repair mechanisms may play a role in their tolerance to radiation (Jönsson et al, 2005;Jönsson, 2007). Few studies on DNA damage and repair in tardigrades have appeared, but Neumann et al (2009) and Rebecchi et al (2009) reported evidence of DNA degradation after exposure to periods of anhydrobiosis, with an increase in damage with time spent in the dry state. Evidence that DNA repair mechanisms are an important part of the tolerance to desiccation and radiation in anhydrobiotic animals also comes from studies on insect larvae (Gusev et al, 2010) and rotifers (Gladyshev and Meselson, 2008).…”