Giovannini Ilaria, Corsetto Paola Antonia, Altiero Tiziana, Montorfano Gigliola, Guidetti Roberto, Rizzo Angela Maria, Rebecchi Lorena
Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy.
Department of Pharmacological and Biomolecular Sciences, University of Milan, 20122 Milan, Italy.
Life (Basel). 2022 May 30;12(6):817. doi: 10.3390/life12060817.
Anhydrobiosis, a peculiar adaptive strategy existing in nature, is a reversible capability of organisms to tolerate a severe loss of their body water when their surrounding habitat is drying out. In the anhydrobiotic state, an organism lacks all dynamic features of living beings since an ongoing metabolism is absent. The depletion of water in the anhydrobiotic state increases the ionic concentration and the production of reactive oxygen species (ROS). An imbalance between the increased production of ROS and the limited action of antioxidant defences is a source of biomolecular damage and can lead to oxidative stress. The deleterious effects of oxidative stress were demonstrated in anhydrobiotic unicellular and multicellular organisms, which counteract the effects using efficient antioxidant machinery, mainly represented by ROS scavenger enzymes. To gain insights into the dynamics of antioxidant patterns during the kinetics of the anhydrobiosis of two tardigrade species, and , we investigated the activity of enzymatic antioxidants (catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase) and the amount of non-enzymatic antioxidants (glutathione) in the course of rehydration. In , the activity of catalase increases during dehydration and decreases during rehydration, whereas in , the activity of superoxide dismutase decreases during desiccation and increases during rehydration. Genomic varieties, different habitats and geographical regions, different diets, and diverse evolutionary lineages may have led to the specialization of antioxidant strategies in the two species.
隐生现象是自然界中一种独特的适应性策略，是生物体在周围栖息地干涸时耐受体内水分严重流失的一种可逆能力。在隐生状态下，生物体缺乏所有生命的动态特征，因为不存在持续的新陈代谢。隐生状态下水分的耗尽会增加离子浓度和活性氧（ROS）的产生。ROS产生增加与抗氧化防御作用有限之间的失衡是生物分子损伤的一个来源，可导致氧化应激。氧化应激的有害影响在隐生单细胞和多细胞生物中得到了证实，这些生物利用主要由ROS清除酶代表的高效抗氧化机制来对抗这些影响。为了深入了解两种缓步动物物种在隐生动力学过程中抗氧化模式的动态变化，我们研究了复水过程中酶促抗氧化剂（过氧化氢酶、超氧化物歧化酶、谷胱甘肽过氧化物酶和谷胱甘肽还原酶）的活性以及非酶促抗氧化剂（谷胱甘肽）的含量。在物种中，过氧化氢酶的活性在脱水过程中增加，在复水过程中降低，而在物种中，超氧化物歧化酶的活性在干燥过程中降低，在复水过程中增加。基因组差异、不同的栖息地和地理区域、不同的饮食以及不同的进化谱系可能导致了这两个物种抗氧化策略的专业化。
