Department of Biological Sciences, East Tennessee State University, Johnson City, TN, 37601, USA.
Department of Biological Sciences, Purdue University Fort Wayne, Fort Wayne, IN, 46805, USA.
Geroscience. 2024 Dec;46(6):6361-6381. doi: 10.1007/s11357-024-01244-7. Epub 2024 Jun 20.
Studies of longevity rely on baseline life expectancy of reference genotypes measured in standardized conditions. Variation among labs, protocols, and genotypes makes longevity intervention studies difficult to compare. Furthermore, extending lifespan under suboptimal conditions or that of a short-lived genotype may be of a lesser theoretical and translational value than extending the maximal possible lifespan. Daphnia is becoming a model organism of choice for longevity research complementing data obtained on traditional models. In this study, we report longevity of several genotypes of a long-lived species D. magna under a variety of protocols, aiming to document the highest lifespan, factors reducing it, and parameters that change with age and correlate with longevity. Combining longevity data from 25 experiments across two labs, we report a strong intraspecific variation, moderate effects of group size and medium composition, and strong genotype-by-environment interactions with respect to food level. Specifically, short-lived genotypes show no caloric restriction (CR) effect, while long-lived ones expand their lifespan even further under CR. We find that the CR non-responsive clones show little correlation between longevity and two measures of lipid peroxidation. In contrast, the long-lived, CR-responsive clones show a positive correlation between longevity and lipid hydroperoxide abundance, and a negative correlation with MDA concentration. This indicates differences among genotypes in age-related accumulation and detoxification of LPO products and their effects on longevity. Our observations support the hypothesis that a long lifespan can be affected by CR and levels of oxidative damage, while genetically determined short lifespan remains short regardless.
长寿研究依赖于在标准化条件下测量的参考基因型的基础预期寿命。实验室、方案和基因型之间的差异使得长寿干预研究难以比较。此外，在次优条件下或短寿命基因型下延长寿命可能不如延长最大可能寿命具有更大的理论和转化价值。水蚤正在成为补充传统模型获得的数据的长寿研究的首选模式生物。在这项研究中，我们报告了几种长寿命物种 D. magna 的基因型在各种方案下的寿命，旨在记录最高寿命、降低寿命的因素以及随年龄变化并与寿命相关的参数。将来自两个实验室的 25 个实验的寿命数据进行组合，我们报告了强烈的种内变异、群体大小和中等组成的适度影响，以及与食物水平相关的强烈基因型-环境相互作用。具体而言，短寿命基因型没有表现出热量限制（CR）效应，而长寿命基因型在 CR 下甚至进一步延长了寿命。我们发现，CR 无反应克隆在寿命和两种脂质过氧化测量值之间几乎没有相关性。相比之下，长寿命、CR 反应性克隆在寿命和脂质氢过氧化物丰度之间呈正相关，与 MDA 浓度呈负相关。这表明不同基因型在与年龄相关的 LPO 产物积累和解毒方面存在差异，以及它们对寿命的影响。我们的观察结果支持这样一种假设，即长寿可以受到 CR 和氧化损伤水平的影响，而遗传决定的短寿命仍然较短。
