An Animal Able To Tolerate D 2 O

It is possible to gain a deeper insight into the role of water in biology by using physicochemical variant molecules, such as deuterium oxide (D 2 O); however, D 2 O is toxic to multicellular organisms in high concentrations. By using a unique desiccation‐rehydration process, we demonstrate that the anhydrobiotic nematode Panagrolaimus superbus is able to tolerate and proliferate in 99 % D 2 O. Moreover, we analysed P. superbus’ water‐channel protein (aquaporin; AQP), which is associated with dehydration/rehydration, by comparing its primary structure and modelling its tertiary structure in silico . Our data evidence that P. superbus ’ AQP is an aquaglyceroporin, a class of water channel known to display a wider pore; this helps to explain the rapid and successful organismal influx of D 2 O into this species. This is the first demonstration of an animal able to withstand high D 2 O levels, thus paving a way for the investigation of the effects D 2 O on higher levels of biological organization.