title: Physiological and biochemical responses to cold and drought in the rock-dwelling pulmonate snail, Chondrina avenacea.
abstract: The pulmonate snail Chondrina avenacea lives on exposed rock walls where it experiences drastic daily and seasonal fluctuations of abiotic conditions and food availability. We found that tolerance to dry conditions was maintained at a very high level throughout the year and was mainly based on the snails' ability to promptly enter into estivation (quiescence) whenever they experienced drying out of their environment. Snails rapidly suppressed their metabolism and minimized their water loss using discontinuous gas exchange pattern. The metabolic suppression probably included periods of tissue hypoxia and anaerobism as indicated by accumulation of typical end products of anaerobic metabolism: lactate, alanine and succinate. Though the drought-induced metabolic suppression was sufficient to stimulate moderate increase of supercooling capacity, the seasonally highest levels of supercooling capacity and the highest tolerance to subzero temperatures were tightly linked to hibernation (diapause). Hibernating snails did not survive freezing of their body fluids and instead relied on supercooling strategy which allowed them to survive when air temperatures dropped to as low as -21 °C. No accumulation of low-molecular weight compounds (potential cryoprotectants) was detected in hibernating snails except for small amounts of the end products of anaerobic metabolism.
authors.affiliation: Institute of Entomology, Biology Centre of the Academy of Sciences, Branišovská 31, 370 05 České Budějovice, Czech Republic. kostal@entu.cas.cz
authors.forename: Vladimír
authors.initials: V
authors.lastname: Koštál
authors.forename: Jan
authors.initials: J
authors.lastname: Rozsypal
authors.forename: Pavel
authors.initials: P
authors.lastname: Pech
authors.forename: Helena
authors.initials: H
authors.lastname: Zahradníčková
authors.forename: Petr
authors.initials: P
authors.lastname: Šimek
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000693:Anaerobiosis / Q000502:physiology; D000818:Animals; D003080:Cold Temperature; D055864:Droughts; D004777:Environment; D004956:Estivation; D006605:Hibernation; D055432:Metabolomics; D010101:Oxygen Consumption / Q000502:physiology; D012621:Seasons; D012908:Snails / Q000502:physiology*