It has been two decades since 1993 when research on the biology of rotifer aging was last reviewed by Enesco. Much has transpired during this time as rotifer biologists have adapted to the "omics" revolution and incorporated these techniques into the experimental analysis of rotifers. Rotifers are amenable to many of these approaches and getting adequate quantities of DNA, RNA, and protein from rotifers is not difficult. Analysis of rotifer genomes, transcriptomes, and proteomes is rapidly yielding candidate genes that likely regulate a variety of features of rotifer biology. Parallel developments in aging biology have recognized the limitations of standard animal models like worms and flies and that comparative aging research has essentially ignored a large fraction of animal phylogeny in the lophotrochozoans. As experimentally tractable members of this group, rotifers have attracted interest as models of aging. In this paper, I review advances over the past 20 years in the biology of aging in rotifers, with emphasis on the unique contributions of rotifer models for understanding aging. The majority of experimental work has manipulated rotifer diet and followed changes in survival and reproductive dynamics like mean lifespan, maximum lifespan, reproductive lifespan, and mortality rate doubling time. The main dietary manipulation has been some form of caloric restriction, withholding food for some period or feeding continuously at low levels. There have been comparative studies of several rotifer species, with some species responding to caloric restriction with life extension, but others not, at least under the tested food regimens. Other aspects of diet are less explored, like nutritional properties of different algae species and their capacity to extend rotifer lifespan. Several descriptive studies have reported many genes involved in rotifer aging by comparing gene expression in young and old individuals. Classes of genes up or down-regulated during aging have become prime targets for rotifer aging investigations. Alterations of gene expression by exposure to specific inhibitors or RNAi knockdown will probably yield valuable insights into the cellular mechanisms of rotifer life extension. I highlight major experimental contributions in each of these areas and indicate opportunities where I believe additional investigation is likely to be profitable.

中文翻译：

---

轮虫作为衰老生物学的模型


自 1993 年 Enesco 上次审查轮虫衰老生物学研究以来，已有二十年了。在此期间，轮虫生物学家已经适应了“组学”革命，并将这些技术纳入轮虫的实验分析中，发生了很多事情。轮虫适合其中的许多方法，并且从轮虫中获取足够数量的 DNA、RNA 和蛋白质并不困难。对轮虫基因组、转录组和蛋白质组的分析正在迅速产生可能调节轮虫生物学多种特征的候选基因。衰老生物学的并行发展已经认识到蠕虫和苍蝇等标准动物模型的局限性，并且比较衰老研究基本上忽略了轮轮虫动物系统发育的很大一部分。作为该群体中实验上易于处理的成员，轮虫作为衰老模型引起了人们的兴趣。在本文中，我回顾了过去 20 年轮虫衰老生物学的进展，重点介绍了轮虫模型对理解衰老的独特贡献。大多数实验工作都操纵轮虫的饮食，并跟踪生存和繁殖动态的变化，如平均寿命、最大寿命、繁殖寿命和死亡率倍增时间。主要的饮食控制是某种形式的热量限制，在一段时间内禁食或持续低水平进食。对几种轮虫物种进行了比较研究，一些物种对热量限制有反应，寿命延长，但其他物种则不然，至少在测试的食物方案下是这样。 饮食的其他方面较少被探索，例如不同藻类的营养特性及其延长轮虫寿命的能力。一些描述性研究通过比较年轻人和老年人的基因表达，报道了许多与轮虫衰老有关的基因。衰老过程中上调或下调的基因类别已成为轮虫衰老研究的主要目标。通过接触特定抑制剂或 RNAi 敲低来改变基因表达可能会对轮虫寿命延长的细胞机制产生有价值的见解。我强调了每个领域的主要实验贡献，并指出了我认为额外研究可能有利可图的机会。