Warm preconditioning protects against acute heat-induced respiratory dysfunction and delays bleaching in a symbiotic sea anemone
Warm preconditioning protects against acute heat-induced respiratory dysfunction and delays bleaching in a symbiotic sea anemone
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DOI：
10.1242/jeb.150391
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发表时间：
2017-03-15
影响因子：
2.8
通讯作者：
Warner, Mark E.
中科院分区：
文献类型：
--
作者：
Hawkins, Thomas D.;Warner, Mark E.
对非应激性升温的预处理可以保护一些共生刺胞动物免受高温诱导的与光合甲藻（共生甲藻属）的互利共生内共生关系的崩溃，一个被称为漂白的过程。在这里，我们试图确定这种预处理是否是由有氧呼吸的差异调节的基础。我们在自然共生海葵Exaiptasia pallida中定量体内代谢和线粒体呼吸酶活性，该海葵预处理至30摄氏度> 7周以及保持在26摄氏度的海葵。预处理导致共生藻光合活性和全生物（主机+共生体）呼吸速率增加。宿主呼吸酶的生物量标准化活动[柠檬酸合酶和线粒体电子传递链（mETC）复合物I和IV]在预处理动物中较高，表明增加的全生生物呼吸可能是由于宿主线粒体生物合成和/或扩大。随后的急性加热预处理和“热幼稚”的动物到33摄氏度诱导显着增加主机mETC复合物I和共生藻mETC复合物II的活动，只有在热幼稚E。苍白球。这些变化没有反映在其他呼吸酶的活动。此外，预处理的E.苍白球（定义为共生体的显著损失）相对于未热处理组延迟数天。这些研究结果表明，在温暖的预处理过程中，共生刺胞动物的线粒体生物发生和/或功能的变化可能在暴露于压力加热期间发挥保护作用。
Preconditioning to non-stressful warming can protect some symbiotic cnidarians against the high temperature-induced collapse of their mutualistic endosymbiosis with photosynthetic dinoflagellates (Symbiodinium spp.), a process known as bleaching. Here, we sought to determine whether such preconditioning is underpinned by differential regulation of aerobic respiration. We quantified in vivo metabolism and mitochondrial respiratory enzyme activity in the naturally symbiotic sea anemone Exaiptasia pallida preconditioned to 30 degrees C for > 7 weeks as well as anemones kept at 26 degrees C. Preconditioning resulted in increased Symbiodinium photosynthetic activity and holobiont (host+ symbiont) respiration rates. Biomassnormalised activities of host respiratory enzymes [citrate synthase and the mitochondrial electron transport chain (mETC) complexes I and IV] were higher in preconditioned animals, suggesting that increased holobiont respiration may have been due to host mitochondrial biogenesis and/or enlargement. Subsequent acute heating of preconditioned and ` thermally naive' animals to 33 degrees C induced dramatic increases in host mETC complex I and Symbiodinium mETC complex II activities only in thermally naive E. pallida. These changes were not reflected in the activities of other respiratory enzymes. Furthermore, bleaching in preconditioned E. pallida (defined as the significant loss of symbionts) was delayed by several days relative to the thermally naive group. These findings suggest that changes to mitochondrial biogenesis and/or function in symbiotic cnidarians during warm preconditioning might play a protective role during periods of exposure to stressful heating.