Anacleto Patrícia, Maulvault Ana Luísa, Lopes Vanessa M, Repolho Tiago, Diniz Mário, Nunes Maria Leonor, Marques António, Rosa Rui
Laboratório Marítimo da Guia, Centro de Oceanografia, Faculdade de Ciências da Universidade de Lisboa, Av. Nossa Senhora do Cabo 939, Cascais 2750-374, Portugal; Divisão de Aquacultura e Valorização (DivAV), Instituto Português do Mar e da Atmosfera (IPMA, I.P.), Av. Brasília, Lisboa 1449-006, Portugal; Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, Rua dos Bragas, 289, Porto 4050-123, Portugal.
Divisão de Aquacultura e Valorização (DivAV), Instituto Português do Mar e da Atmosfera (IPMA, I.P.), Av. Brasília, Lisboa 1449-006, Portugal; Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, Rua dos Bragas, 289, Porto 4050-123, Portugal.
Comp Biochem Physiol A Mol Integr Physiol. 2014 Sep;175:28-37. doi: 10.1016/j.cbpa.2014.05.003. Epub 2014 May 15.
Both climate change and biological invasions are among the most serious global environmental threats. Yet mechanisms underlying these eventual interactions remain unclear. The aim of this study was to undertake a comprehensive examination of the physiological and biochemical responses of native (Ruditapes decussatus) and alien-invasive (Ruditapes philippinarum) clams to environmental warming. We evaluated thermal tolerance limits (CTMax), routine metabolic rates (RMRs) and respective thermal sensitivity (Q10 values), critical oxygen partial pressure (Pcrit), heat shock response (HSP70/HSC70 levels), lipid peroxidation (MDA build-up) and antioxidant enzyme [glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD)] activities. Contrary to most studies that show that invasive species have a higher thermal tolerance than native congeners, here we revealed that the alien-invasive and native species had similar CTMax values. However, warming had a stronger effect on metabolism and oxidative status of the native R. decussatus, as indicated by the higher RMRs and HSP70/HSC70 and MDA levels, as well as GST, CAT and SOD activities. Moreover, we argue that the alien-invasive clams, instead of up-regulating energetically expensive cellular responses, have evolved a less demanding strategy to cope with short-term environmental (oxidative) stress-pervasive valve closure. Although efficient during stressful short-term periods to ensure isolation and guarantee longer survival, such adaptive behavioural strategy entails metabolic arrest (and the enhancement of anaerobic pathways), which to some extent will not be advantageous under the chronically warming conditions predicted in the future.
气候变化和生物入侵都是最严重的全球环境威胁。然而，这些最终相互作用背后的机制仍不清楚。本研究的目的是全面考察本地蛤（波纹巴非蛤）和外来入侵蛤（菲律宾蛤仔）对环境变暖的生理和生化反应。我们评估了热耐受极限（CTMax）、常规代谢率（RMRs）及其各自的热敏感性（Q10值）、临界氧分压（Pcrit）、热休克反应（HSP70/HSC70水平）、脂质过氧化（MDA积累）和抗氧化酶[谷胱甘肽-S-转移酶（GST）、过氧化氢酶（CAT）和超氧化物歧化酶（SOD）]活性。与大多数表明入侵物种比本地同属物种具有更高热耐受性的研究相反，我们在此揭示外来入侵物种和本地物种具有相似的CTMax值。然而，变暖对本地波纹巴非蛤的代谢和氧化状态影响更大，表现为更高的RMRs、HSP70/HSC70和MDA水平，以及GST、CAT和SOD活性。此外，我们认为外来入侵蛤不是上调耗能巨大的细胞反应，而是进化出了一种要求较低的策略来应对短期环境（氧化）应激——普遍的瓣膜关闭。虽然这种适应性行为策略在压力短期期间有效，可确保隔离并保证更长的存活时间，但在未来预测的长期变暖条件下，这种策略会导致代谢停滞（以及厌氧途径的增强），在某种程度上并不有利。
