日本京都大學研究人員在12月14日的英國《自然》（Nature）雜志網絡版上發(fā)表論文說,，他們以線蟲為研究對象的實驗表明,，在線蟲攝取總熱量不變的條件下，讓它們反復禁食，可延長其壽命。
線蟲寄生于動植物體內，或自由生活于土壤,、淡水和海水環(huán)境中，小的身長不足1毫米,，壽命約25天,。京都大學細胞生物學教授西田榮介的研究小組在兩天內喂給線蟲充足的餌料，在接下去的兩天內又不給線蟲喂食,，如此反復,。結果，研究人員發(fā)現(xiàn),，與每天堅持喂食的線蟲相比,，那些反復讓它們禁食的線蟲,，雖然攝取的總熱量并沒有減少，但其壽命達到36天至40天,，且非?；钴S。
研究人員的深入分析發(fā)現(xiàn),，那些雖被反復禁食但壽命卻延長的線蟲體內有一種名為“Rheb”的基因發(fā)揮著作用,，如果抑制這個基因的活動，即使讓線蟲禁食,，或減少喂給它們的餌料,，線蟲的壽命也不會延長。
之前,，科學家們通過各種動物實驗都證實了限制熱量攝入可延長動物壽命,，而上述實驗則證明，動物進食時盡可能讓它們吃飽,，同時定期讓它們禁食,，也能延長動物壽命。研究人員認為,，這項研究成果對了解人類通過控制進食防病益壽或許有幫助,。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
