日本京都大学研究人员在12月14日的英国《自然》（Nature）杂志网络版上发表论文说，他们以线虫为研究对象的实验表明，在线虫摄取总热量不变的条件下，让它们反复禁食，可延长其寿命。
线虫寄生于动植物体内，或自由生活于土壤、淡水和海水环境中，小的身长不足1毫米，寿命约25天。京都大学细胞生物学教授西田荣介的研究小组在两天内喂给线虫充足的饵料，在接下去的两天内又不给线虫喂食，如此反复。结果，研究人员发现，与每天坚持喂食的线虫相比，那些反复让它们禁食的线虫，虽然摄取的总热量并没有减少，但其寿命达到36天至40天，且非常活跃。
研究人员的深入分析发现，那些虽被反复禁食但寿命却延长的线虫体内有一种名为“Rheb”的基因发挥着作用，如果抑制这个基因的活动，即使让线虫禁食，或减少喂给它们的饵料，线虫的寿命也不会延长。
之前，科学家们通过各种动物实验都证实了限制热量摄入可延长动物寿命，而上述实验则证明，动物进食时尽可能让它们吃饱，同时定期让它们禁食，也能延长动物寿命。研究人员认为，这项研究成果对了解人类通过控制进食防病益寿或许有帮助。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature，doi:10.1038/nature07583，Sakiko Honjoh，Eisuke Nishida
Signalling through RHEB-1 mediates intermittent fasting-induced longevity in C. elegans
Sakiko Honjoh1, Takuya Yamamoto1, Masaharu Uno1 & Eisuke Nishida1
Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
Dietary restriction is the most effective and reproducible intervention to extend lifespan in divergent species1. In mammals, two regimens of dietary restriction, intermittent fasting (IF) and chronic caloric restriction, have proven to extend lifespan and reduce the incidence of age-related disorders2. An important characteristic of IF is that it can increase lifespan even when there is little or no overall decrease in calorie intake2. The molecular mechanisms underlying IF-induced longevity, however, remain largely unknown. Here we establish an IF regimen that effectively extends the lifespan of Caenorhabditis elegans, and show that the low molecular weight GTPase RHEB-1 has a dual role in lifespan regulation; RHEB-1 is required for the IF-induced longevity, whereas inhibition of RHEB-1 mimics the caloric-restriction effects. RHEB-1 exerts its effects in part by the insulin/insulin growth factor (IGF)-like signalling effector DAF-16 in IF. Our analyses demonstrate that most fasting-induced upregulated genes require RHEB-1 function for their induction, and that RHEB-1 and TOR signalling are required for the fasting-induced downregulation of an insulin-like peptide, INS-7. These findings identify the essential role of signalling by RHEB-1 in IF-induced longevity and gene expression changes, and suggest a molecular link between the IF-induced longevity and the insulin/IGF-like signalling pathway.
