Project description:Recent studies have shown that proteins unique to tardigrades are involved in the remarkable ability of these small animals to withstand desiccation and ionizing radiation (IR). For resistance to IR, only one tardigrade unique protein has been identified so far: Dsup, for DNA damage suppressor, found in R. varieornatus and H. exemplaris. Rv-Dsup protects from DNA damage by X-rays in human cells, suggesting that DNA protection is important for resistance to IR. Here, we chose to investigate the role of DNA repair and search for novel tardigrade unique genes involved in resistance to IR. For this, we performed an unbiased proteome analysis of H. exemplaris either untreated, or at 4h post-irradiation, 24h post-irradiation and after Bleomycin treatment.
Project description:The ability of the Antarctic microarthropod, Cryptopygus antarcticus (Collembola, Isotomidae), to survive low temperatures has been well studied at the physiological level. These investigations have indicated the importance of the moulting process in conferring this ability. This study investigated gene expression in groups of C. antarcticus that have distinct differences in their ability to survive low temperatures. A microarray containing 5,400 C. antarcticus expressed sequence tags was used to investigate gene expression differences between groups of animals with different supercooling points (SCP), and to low temperatures close to their SCP. By demonstrating the involvement of moulting genes in the differential survival of two groups of C. antarcticus with distinct SCPs, the results of this investigation add support to the role moulting plays in conferring cold tolerance in C. antarcticus.
Project description:Tardigrades are microscopic organisms, famous for their tolerance against extreme environments. The establishment of rearing systems of multiple species has allowed for comparison of tardigrade physiology, in particular in embryogenesis. Interestingly, in-lab cultures of limnic species showed smaller variation in hatching timing than terrestrial species, suggesting a hatching regulation mechanism acquired by adaptation to their habitat. To this end, we screened for coordinated gene expression during the development of two species of tardigrades, Hypsibius exemplaris and Ramazzottius varieornatus, and observed induction of the arthropod molting pathway. Exposure of ecdysteroids and juvenile hormone analog affected egg hatching but not embryonic development in only the limnic H. exemplaris. These observations suggest a hatching regulation mechanism by the molting pathway in H. exemplaris.
