The animals are really tough and long-living, one of the reasons why M. tardigradum is more carnivorous, feeding on rotifers and nematodes. Most water bears prefer vegetarian food, M. It has unique anatomy and motion characteristics compared to other water bears. Milnesium tardigradum is an abundant and ubiquitous terrestrial tardigrade species in Europe and possibly worldwide. Molecular data are sparse but include the purinergic receptor occuring in H. dujardini have a stereotyped cleavage pattern with asymmetric cell divisions, nuclear migrations, and cell migrations occurring in reproducible patterns. dujardini has a short generation time, 13-14 days at room temperature. dujardini is similar to that of other metazoan taxa. It has a compact genome, a little smaller than that of Caenorhabditis elegans or Drosophila melanogaster, and the rate of protein evolution in H. dujardini can be cultured continuously for decades and can be cryopreserved. Well known species include Hypsibius dujardini which is an obligatory parthenogenetic species. Moreover, the tun is resistant to extreme pressures and temperatures (low/high), as well as radiation and vaccuum. A dehydrated tardigrade, known as anhydrobiotic tun-stage, can survive for years without water. They are a phylum of multi-cellular animals capable of reversible suspension of their metabolism and entering a state of cryptobiosis. Tardigrades are small metazoans resembling microscopic bears ("water-bears", 0.05 mm to 1.5 mm in size) and live in marine, freshwater and terrestrial environments, especially in lichens and mosses. The work-bench offers nucleotide pattern analysis for promotor and regulatory element detection (tardigrade specific nrdb) as well as rapid COG search for function assignments including species-specific repositories of all analysed data. Further features of tardigrade specific adaption are rapidly identified by sequence and/or pattern search on the web-tool tardigrade analyzer. Specific regulatory elements regulate tardigrade mRNA stability such as lox P DICE elements whereas 14 other RNA elements of higher eukaryotes are not found. Tardigrade-specific functional adaptations include strong protein, DNA- and redox protection, maintenance and protein recycling. Among these are ten tardigrade specific as well as a number of stress-specific protein clusters. We find that 39.3% of the total sequences clustered in 58 clusters of more than 20 proteins.
To gain insights into their stress-specific adaptation potential, major clusters of related and similar proteins are identified, as well as specific functional clusters delineated comparing all tardigrades and individual species ( Milnesium tardigradum, Hypsibius dujardini, Echiniscus testudo, Tulinus stephaniae, Richtersius coronifer) and functional elements in tardigrade mRNAs are analysed.