Trehalose accumulation in the tardigrade Adorybiotus coronifer during anhydrobiosis

Abstract Changes in the trehalose level in the tardigrade Adorybiotus coronifer were observed during induction of, and arousal from, anhydrobiosis. A trehalose accumulation surpassing 1.6% dry weight (d.w.) in anhydrobiotic animals collected dry on their biotope was rapidly reduced on rehydration, reaching the level of active animals (0.1–0.2% d.w.) after 6 hours. Tardigrades dried while embedded in sand in the laboratory accumulated trehalose from 0.1% to 2.3% d.w. within 5–7 hours. Induction of aerobic acidosis in arousing tardigrades by CO2 perfusion reversibly arrested reactivation for at least 36 hours and induced a reduction in anabolic and catabolic activities, measured as a significant reduction in trehalose degradation, and a sevenfold reduction in the rate of protein synthesis. These data support the hypotheis that trehalose generally serves a protective role in desiccationtolerant Metazoa, but indicate that tardigrades require only a moderate level for efficient protection.