Bisquert Ricardo, Muñiz-Calvo Sara, Guillamón José M
Departamento de Biotecnología de Alimentos, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Valencia, Spain.
Front Microbiol. 2018 Feb 28;9:318. doi: 10.3389/fmicb.2018.00318. eCollection 2018.
Melatonin (Mel) is considered a potent natural antioxidant molecule given its free-radical scavenging ability. Its origin is traced back to the origin of aerobic life as early defense against oxidative stress and radiation. More complex signaling functions have been attributed to Mel as a result of evolution in different biological kingdoms, which comprise gene expression modulation, enzyme activity, and mitochondrial homeostasis regulation processes, among others. Since Mel production has been recently reported in wine yeast, we tested the protective effect of Mel on against oxidative stress and UV light. As the optimal conditions for to synthesize Mel are still unknown, we developed an intracellular Mel-charging method to test its effect against stresses. To assess Mel's ability to protect from both stresses, we ran growth tests in liquid media and viability assays by colony count after Mel treatment, followed by stress. We also analyzed gene expression by qPCR on a selection of genes involved in stress protection in response to Mel treatment under oxidative stress and UV radiation. The viability in the Mel-treated cells after HO stress was up to 35% greater than for the untreated controls, while stress amelioration reached 40% for UVC light (254 nm). Mel-treated cells showed a significant shortened lag phase compared to the control cells under the stress and normal growth conditions. The gene expression analysis showed that Mel significantly modulated gene expression in the unstressed cells in the exponential growth phase, and also during various stress treatments.
褪黑素（Mel）因其自由基清除能力而被认为是一种强大的天然抗氧化分子。其起源可追溯到有氧生命的起源，作为对氧化应激和辐射的早期防御。由于不同生物界的进化，Mel具有了更复杂的信号功能，包括基因表达调控、酶活性以及线粒体稳态调节等过程。鉴于最近报道葡萄酒酵母中能产生Mel，我们测试了Mel对氧化应激和紫外线的保护作用。由于合成Mel的最佳条件仍未知，我们开发了一种细胞内Mel加载方法来测试其对压力的影响。为评估Mel保护免受这两种压力的能力，我们在液体培养基中进行生长测试，并在Mel处理后通过菌落计数进行活力测定，随后施加压力。我们还通过qPCR分析了在氧化应激和紫外线辐射下，响应Mel处理的一组参与应激保护的基因的表达。在过氧化氢应激后，Mel处理的细胞活力比未处理的对照高出35%，而对于254nm的紫外线，应激缓解达到40%。与对照细胞相比，在应激和正常生长条件下，Mel处理的细胞显示出显著缩短的延迟期。基因表达分析表明，Mel在指数生长期的未应激细胞以及各种应激处理期间均显著调节基因表达。
