title: Anhydrobiosis Affects Thermal Habituation in the Bdelloid Rotifer, Adineta sp.
abstract: The bdelloid rotifer of the genus Adineta is a freshwater metazoan characterized by anhydrobiosis, a highly stable state of suspended animation induced by desiccation. This study investigated the influence of anhydrobiosis on the thermal habituation by use of an index, Activity Ratio (AR = the number of active rotifers at each experimental temperature/ number of active rotifers at the 25°C stage). In the first experiment, rotifers were divided into two groups: one group was cultivated at 25°C throughout experiment, and another group was transferred to 15°C for two days. AR was estimated during heating up to 40°C, or during cooling down to 5°C in each group. The largest difference in AR occurred at 35°C and 10°C, indicating that AR was changed depending on the pretreated medium temperature. In the next experiment, rotifers were maintained at 15°C, and were desiccated (anhydrobiosis). AR was estimated in the high temperature range (25°C to 40°C), using rotifers that had recovered from anhydrobiosis. AR was significantly different between the groups with and without desiccation, suggesting that thermal habituation at 15°C was completely cancelled by anhydrobiosis. Possible mechanisms on the influence of anhydrobiosis on the thermal habituation have been discussed in terms of neural changes and proteins.
authors.affiliation: 1 Department of Biology, Faculty of Science, Okayama University, Tsushima 3-1-1, Okayama-Kitaku 700-8530, Japan.
authors.forename: Mai
authors.initials: M
authors.lastname: Kanazawa
authors.affiliation: 2 Section of Research and Education, The Biosphere Project (Non-Profit Organization), Tsushima-Fukui 1-8-71, Okayama-Kitaku 700-0080, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nanri
authors.affiliation: 2 Section of Research and Education, The Biosphere Project (Non-Profit Organization), Tsushima-Fukui 1-8-71, Okayama-Kitaku 700-0080, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Saigusa
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D006358:Hot Temperature; D012403:Rotifera / Q000502:physiology*; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water
keywords: anhydrobiosis; bdelloid rotifer; desiccation; habituation; temperature