Author
TROEN, ARON - TUFTS/HNRCA | |
FRENCH, EMILY - TUFTS/HNRCA | |
ROBERTS, JESSICA - TUFTS/HNRCA | |
SELHUB, JACOB - TUFTS/HNRCA | |
Ordovas, Jose | |
Parnell, Laurence | |
Lai, Chao Qiang |
Submitted to: Age
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/21/2006 Publication Date: 11/25/2006 Citation: Troen, A.M., French, E.E., Roberts, J.F., Selhub, J., Ordovas, J.M., Parnell, L.D., Lai, C. 2006. Lifespan modification by glucose and methionine in Drosophila melanogaster fed a chemically defined diet. Age.29:29-39. Interpretive Summary: Studies in a variety of different species have shown that experimentally limiting the amount of energy in food consumed (calories) while taking care to maintain adequate content of nutrients (such as vitamins and minerals) can extend lifespan. In some cases the impact of this so called “caloric restriction” may depend on source of energy source – that is whether the calories come from protein, sugars or fat. The lifespan of the common laboratory fruit fly can be considerably extended by limiting their energy intake through yeast restriction, while limiting their energy to the same extent by limiting their sugar but allowing them to consume yeast does not greatly extend lifespan. In rodents, restricting intake of a single amino acid – methionine – extends lifespan. Here we show that dietary methionine can modify lifespan in adult female, fruit flies fed a synthetic food with carefully controlled amino acid, sugar and nutrient content. Compared to a diet containing 0.135% methionine and 15% sugar, high dietary methionine (0.405%) shortened maximum lifespan by 2.33% from 86 to 84 days and average lifespan by 9.55% from 71.7 to 64.9 days. Further restriction of methionine to 0.045% did not extend maximum lifespan and shortened average lifespan by 1.95% from 71.1 to 70.3 days. Restricting sugar from 15 to 5% while holding methionine at a concentration of 0.135% methionine, modestly extended maximum lifespan by 5.8% from 86 to 91 days, without extending average lifespan. Notably, all four diets resulted in considerably longer life spans than those typically reported for flies fed conventional yeast and sugar based diets. Such synthetic food can be used to study the ways in which nutrients affect metabolism and lifespan in the fruit fly. Technical Abstract: Experimentally restricting dietary calories, while maintaining adequate dietary nutrient content, extends lifespan in phylogenetically diverse species; thus suggesting the existence of conserved pathways which can modify lifespan in response to energy intake. However, in some cases the impact on longevity may depend on the quality of the energy source. In Drosophila, restriction of dietary yeast yields considerable lifespan extension whereas isocaloric restriction of dietary sugar yields only modest extension, indicating that other diet-responsive pathways can modify lifespan in this species. In rodents, restricting intake of a single amino acid – methionine – extends lifespan. Here we show that dietary methionine can modify lifespan in adult female, non-virgin Oregon-R strain Drosophila fed a chemically defined media. Compared to a diet containing 0.135% methionine and 15% glucose, high dietary methionine (0.405%) shortened maximum lifespan by 2.33% from 86 to 84 days and mean lifespan by 9.55% from 71.7 to 64.9 days. Further restriction of methionine to 0.045% did not extend maximum lifespan and shortened mean lifespan by 1.95% from 71.1 to 70.3 days. Restricting glucose from 15 to 5% while holding methionine at a concentration of 0.135% methionine, modestly extended maximum lifespan by 5.8% from 86 to 91 days, without extending mean lifespan. All these diet induced changes were highly significant (log-rank p<0.0001). Notably, all four diets resulted in considerably longer life spans than those typically reported for flies fed conventional yeast and sugar based diets. Such defined diets can be used to identify lifespan-modifying pathways and specific gene-nutrient interactions in Drosophila. |