Recovery and reproduction of an Antarctic tardigrade retrieved from a moss sample frozen for over 30 years

Abstract

Long-term survival has been one of the most studied of the extraordinary physiological characteristics of cryptobiosis in micrometazoans such as nematodes, tardigrades and rotifers. In the available studies of long-term survival of micrometazoans, instances of survival have been the primary observation, and recovery conditions of animals or subsequent reproduction are generally not reported. We therefore documented recovery conditions and reproduction immediately following revival of tardigrades retrieved from a frozen moss sample collected in Antarctica in 1983 and stored at -20 °C for 30.5 years. We recorded recovery of two individuals and development of a separate egg of the Antarctic tardigrade, Acutuncus antarcticus, providing the longest records of survival for tardigrades as animals or eggs. One of the two resuscitated individuals and the hatchling successfully reproduced repeatedly after their recovery from long-term cryptobiosis. This considerable extension of the known length of long-term survival of tardigrades recorded in our study is interpreted as being associated with the minimum oxidative damage likely to have resulted from storage under stable frozen conditions. The long recovery times of the revived tardigrades observed is suggestive of the requirement for repair of damage accrued over 30 years of cryptobiosis. Further more detailed studies will improve understanding of mechanisms and conditions underlying the long-term survival of cryptobiotic organisms.

Will the Antarctic tardigrade Acutuncus antarcticus be able to withstand environmental stresses due to global climate change?

“…tolerance (Yamaguchi et al, 2012;Tanaka et al, 2015;Hashimoto et al, 2016;Boothby et al, 2017). In addition to its capability of entering anhydrobiosis, A. antarcticus is also able to tolerate freezing of its habitat through cryobiosis (Altiero et al, 2015), as also demonstrated by the survival of specimens after more than 30 years of storage at -20°C within a frozen moss sample (Tsujimoto et al, 2016). These two cryptobiotic capabilities, together with a short life cycle and reproduction via thelytokous parthenogenesis (Altiero et al, 2015), allow A. antarcticus to synchronize growth and reproduction with favourable environmental conditions, and to persist in habitats where conditions can change unpredictably even within the same day, such as the Antarctic ponds in which it lives.…”

DNA Protection Protein, a Novel Mechanism of Radiation Tolerance: Lessons from Tardigrades

“…Currently, approximately 1200 species have been reported from various habitats, such as marine, fresh-water, or limno-terrestrial environments, though the real number of tardigrade species is estimated to be much higher [4,5]. Tardigrades were found in harsh environments such as Antarctica as well as in urban area, e.g., from activated sludge in a sewage treatment plant [6,7,8]. All tardigrades require surrounding water to grow and reproduce, but some limno-terrestrial species are able to tolerate almost complete dehydration.…”

The Resolved Mystery of Tardigrades

“…It was proved before that they undergo several morphological changes like tun formation or glass like dried structure formation due to desiccation. 10 But what was the factor that helped them to rehydrate and bring back to life still remained a mystery.…”