A long-lived species of zooplankton microcrustaceans, Daphnia magna, sometimes exhibits late-life rebound of reproduction, briefly reversing reproductive senescence. Such events are often interpreted as terminal investments in anticipation of imminent mortality. We demonstrate that such post-senescence reproductive events (PSREs) neither cause nor anticipate increased mortality. We analyze an RNAseq experiment comparing young, old reproductively senescent, and old PSRE Daphnia females. We first show that overall age-related transcriptional changes are dominated by the increased transcription of guanidine monophosphate synthases and guanylate cyclases, as well as two groups of presumed transposon-encoded proteins, and by a drop in transcription of protein synthesis-related genes. We then focus on gene families and functional groups in which full or partial reversal of age-related transcriptional changes occur. This analysis reveals a reversal, in the PSRE individuals, of age-related up-regulation of apolipoproteins D, lysosomal lipases, and peptidases as well as several proteins related to mitochondrial and muscle functions. While it is not certain which of these changes enable reproductive rejuvenation, and which are by-products of processes that lead to it, we present some evidence that post-senescence reproductive events are associated with the reversal of age-related protein and lipid aggregates removal and apoptosis.

浮游动物微甲壳类动物的一种长寿物种，大溞（Daphnia magna），有时会表现出晚年的繁殖反弹，短暂地逆转生殖衰老。此类事件通常被解释为预期即将到来的死亡的终端投资。我们证明，这种衰老后生殖事件 （PSRE） 既不会导致也不预期死亡率增加。我们分析了一项 RNAseq 实验，比较了年轻、年老、生殖衰老和老年 PSRE 水蚤雌性。我们首先表明，总体与年龄相关的转录变化主要由胍单磷酸合酶和鸟苷酸环化酶的转录增加，以及两组假定的转座子编码的蛋白质，以及蛋白质合成相关基因的转录下降主导。然后，我们专注于基因家族和功能组，其中发生与年龄相关的转录变化的完全或部分逆转。该分析揭示了 PSRE 个体中载脂蛋白 D、溶酶体脂肪酶和肽酶以及与线粒体和肌肉功能相关的几种蛋白质的年龄相关上调的逆转。虽然不确定这些变化中的哪些能够实现生殖年轻化，哪些是导致生殖年轻化的过程的副产品，但我们提供了一些证据表明，衰老后生殖事件与年龄相关蛋白质和脂质聚集体去除和细胞凋亡的逆转有关。