Anhydrobiosis in tardigrades and its effects on longevity traits

Abstract

Living in harsh and variable environments that are prone to periodic desiccation, tardigrades exhibit remarkable tolerance against physical extremes through a state known as anhydrobiosis. To study the effect of this state on the longevity and hence the lifecycle in the taxon Tardigrada for the first time, we exposed a tardigrade species, Milnesium tardigradum, to alternating periods of drying and active feeding periods in a hydrated state. Compared with a hydrated control, the periodically dried animals showed a similar longevity, indicating that the time spent in anhydrobiosis was ignored by the internal clock. Thus, desiccation can produce a time shift in the age of tardigrades similar to the model described for rotifers that has been termed 'Sleeping Beauty'.

The importance of being a bdelloid: Ecological and evolutionary consequences of dormancy

“…This is detectable when age-specific traits are analysed Ricci & Pagani 1997;Ricci 2001;Ricci & Covino 2004;Ricci & Caprioli 2005;Ricci & Perletti 2006). A recent study on another group of anhydrobiotic micrometazoans, the tardigrades, has shown that this taxon, as well, behaves like a sleeping beauty (Hengherr et al 2008). …”

Survival and DNA degradation in anhydrobiotic tardigrades

“…The survival of desiccated tardigrades under atmospheric oxygen conditions can be long (nine years) but seems not to exceed 20 years (Baumann, 1927;Guidetti and Jönsson, 2002;Rebecchi et al, 2006;Jørgensen et al, 2007). This means that during anhydrobiosis some damages occur leading to the death of tardigrades (Rebecchi et al, 2006), even though desiccation does not seem to have an effect on their aging and longevity because under alternating periods of desiccation (seven days) and of active life (seven days) the time spent in anhydrobiosis is ignored (Hengherr et al, 2008a).…”

Stress response in tardigrades: differential gene expression of molecular chaperones

“…In the anhydrobiotic state, their metabolism is barely measurable (Pigoń and Węglarska 1955). The longer the animals spend in this state of suspended animation, the longer their lifespan (Hengherr et al 2008a). The animals resume activity after successful rehydration.…”