Aestivation During The Gray Tip Bradybaena Energy Utilization And The Antioxidant Levels

Aestivation is a complex phenomenon and several influences may be at work to readjust metabolism for optimal function over the long months of dormancy. One of these is the pattern of stored fuel use during aestivation, including a major reliance on the oxidation of body lipid reserves, a low rate of gluconeogenesis from glycerol or amino acids to maintain glucose supply for selected organs, and a gradual rise in protein catabolism as the demand for urea synthesis increases. Another influence on metabolism reorganization during aestivation may be metabolic arrest. Whereas some enzymes are regulated via reversible phosphorylation to achieve the hypometabolism during aestivation, and some may be influenced by changes in the lipid environment in which they reside, others may be controlled by synthesis or degradation with the resulting changes in the maximal activities of selected enzymes contributing to the suppression of different metabolic pathways. Only under the condition of determinate tissue water content, the metabolism can subsequently process, so it important to aestivating animal for perfect mechanism of water maintenance, commonly water keeping relies on physical and metabolic methods. As in a highly anoxia state, the tissue of aestivating animal can be damaged by oxidation for inbreathing large content of oxygen during arouse from aestivation on mutable environment, accordingly the antioxidant system in body may be readjust itself.Land snails in temperate regions often exhibit intra-annual cycles of activity interspersed by periods of dormancy (aestivation and hibernation), accompanied by a range of behavioral and physiological adaptations to ensure their survival under adverse environmental conditions. In the long process of evolution, the behavioral and physiological adaptations of land snails is greatly related to some environmental factors, such as photoperiod, temperature, humidity and so on. so it can be useful in understanding species-specific habitat selection and predicting their response to future environmental changes for studying the changes of behavioral and biochemical indexes of land snails during aestivation.This paper mainly focuses on the primary adjustments of snail Bradybaena (Acusta) ravida ravida (Benson, 1842) to fuel using, water maintenance and antioxidant plane at behavioral and physiological levels, and reaches several conclusions as follows from experiments.1. In the process of 17 days' aestivation at 30℃, snails B.ravida ravida showed behavioral adaptations, such as the selection of aestivation site, shell thickened, shell color became light, respiratory depression and so on..2.The weight of snails B.ravida ravida decreased slowly with the prolonging of aestivationtime, maybe it's the result of jointly actions of stop feeding and metabolic depression. 3. Foot, hepatopancreas and genitalia all showed good maintenance of water, which depend on epiphragm formation and metabolic water-supply in aestivation, Foot supplied water by the metabolism of glycogen and adipose, and it improved osmotic pressure of tissue to meet water conservation by urea from protein degradation, and the water produced by fat metabolism had been sustaining hepatopancreas water content, there was no correlation between maintenance of genitalia water content and the water-supply produced by itself, which could be guessed its water-supply from other tissues.4.During aestivation, B.ravida ravida relied on glycogen for the energy supply firstly, and on protein secondly. As for the decomposition of lipids which can be seen during the whole aestivation, it was not conspicuously observed until the middle of aestivation.5.During aestivation, snail displayed tradeoff, on fuel molecular in the way of employing reserve of fuel. The glycogen, proteins and lipids in hepatopancreas were employed firstly, where the glycogen and proteins in foot were consumed slowly.6.The SOD activities in foot and hepatopancreas fluctuated up and down during 17 days' aestivation, we guessed that this fluctuation was related to the pattern of discontinuous breathing.