School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow G12 8QQ, UK.
Ecology, Evolution and Development Group, Doñana Biological Station (CSIC), 41092, Seville, Spain.
Proc Biol Sci. 2023 Feb 8;290(1992):20222448. doi: 10.1098/rspb.2022.2448.
Telomere attrition is considered a useful indicator of cellular and whole-organism ageing rate. While approximately 80% of animal species undergo metamorphosis that includes extensive tissue transformations (involving cell division, apoptosis, de-differentiation and formation of stem cells), the effect on telomere dynamics is unknown. We measured telomeres in developing from larvae to adults under contrasting environmental temperatures Telomere dynamics were linked to the degree of tissue transformation during development. Average telomere length in gut tissue increased dramatically during metamorphosis, when the gut shortens by 75% and epithelial cells de-differentiate into stem cells. In the liver (retained from larva) and hindlimb muscle (newly formed before metamorphosis), telomeres gradually shortened until adulthood, likely due to extensive cell division. Tail muscle telomere lengths were constant until tail resorption, and those in heart (retained from larva) showed no change over time. Telomere lengths negatively correlated with larval growth, but for a given growth rate, telomeres were shorter in cooler conditions, suggesting that growing in the cold is more costly. Telomere lengths were not related to post-metamorphic growth rate. Further research is now needed to understand whether telomere dynamics are a good indicator of ageing rate in species undergoing metamorphosis.
端粒损耗被认为是细胞和整个生物体衰老速度的有用指标。虽然大约 80%的动物物种经历包括广泛组织转化（涉及细胞分裂、细胞凋亡、去分化和干细胞形成）的变态，但对端粒动力学的影响尚不清楚。我们在对比环境温度下测量了幼虫发育为成虫过程中端粒的变化。端粒动力学与发育过程中的组织转化程度有关。在变态过程中，肠道缩短 75%，上皮细胞去分化为干细胞，肠道组织中端粒的平均长度显著增加。在肝脏（保留自幼虫）和后肢肌肉（在变态前新形成）中，端粒逐渐缩短直到成年期，可能是由于广泛的细胞分裂。尾巴肌肉的端粒长度保持不变，直到尾巴被吸收，而心脏（保留自幼虫）的端粒在整个过程中没有变化。端粒长度与幼虫生长呈负相关，但对于给定的生长速度，在较冷的条件下端粒更短，这表明在寒冷中生长的代价更高。端粒长度与变态后的生长速度无关。现在需要进一步研究，以了解在经历变态的物种中，端粒动力学是否是衰老速度的良好指标。
