A dietary sterol trade-off determines lifespan responses to dietary restriction in Drosophila melanogaster females
- Monash University, School of Biological Sciences, Australia
Figures
Figure 1
Changing dietary protein and carbohydrate concentrations modify Drosophila lifespan and fecundity.
(a, b) Lifespan was maximised at our intermediate dose of dietary protein (carbohydrate fixed at 17.1 g/l) but was unaffected by our carbohydrate (c, d) concentration range (protein fixed at 9.7 …
Figure 2 with 2 supplements
Dietary cholesterol content significantly modified the effect of protein and carbohydrate content on lifespan and reproduction.
Lowering cholesterol most severely compromised lifespan as protein levels increased and as carbohydrate levels decreased. In general, increasing protein and decreasing carbohydrate drove increasing …
Figure 2—figure supplement 1
Changing dietary protein and cholesterol concentrations modify Drosophila lifespan (a–c), while changing protein, cholesterol and carbohydrate concentrations modify egg production (d–f).
Diets varying in protein and carbohydrate concentration were each made at 4 levels of cholesterol (b, e) 0 g/l, 0.15 g/l, 0.3 g/l and 0.6 g/l. (a) Lifespan is reduced at both low and high protein …
Figure 2—figure supplement 2
Dietary energy intake (calories) does not mediate lifespan or egg production in Drosophila (a, b), while changing P:C ratio and cholesterol do (a, b).
Diets varying in protein and carbohydrate concentration were each made at three alternate P:C ratios, four levels of cholesterol (a, b) 0 g/l, 0.15 g/l, 0.3 g/l and 0.6 g/l, and five caloric …
Figure 3
Increasing dietary protein: carbohydrate ratio resulted in increased egg production at every level of cholesterol.
This positive effect was stronger from 0 g/l cholesterol (a) to 0.15 g/l (c) and 0.3 g/l (e). There was no additional benefit of further increasing cholesterol to 0.6 g/l (g). Regression lines show …
Figure 4
Rapamycin extends lifespan in flies consuming a low cholesterol diet (0.1 g/l) but had no effect when cholesterol level was increased to 0.3 g/l.
(a) There was no significant difference in lifespan amongst flies fed 0.3 g/l cholesterol, 0.3 g/l cholesterol + rapamycin or 0.1 g/l cholesterol + rapamycin, all of which were significantly longer …
Figure 5
Cholesterol supplementation significantly extended lifespan and promoted egg laying of flies fed yeast-based diets.
(a) Adding dietary cholesterol significantly increased the lifespan of flies on both high and low concentrations of diets made with autolysed yeast (low yeast v low yeast + cholesterol and high …
Figure 6
Experimental diets used are indicated by coloured dots.
These diets have varying protein: carbohydrate ratios. This makes a total of five different experimental diets (a). The standard cholesterol concentration is 0.3 g/l. Three additional cholesterol …
Tables
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Chemical compound, drug | Rapamycin (Sirolimus) | Jomar Life Research | S1039 |
Table 1
Protein: carbohydrate ratio, along with the nutrient densities, cholesterol concentration and caloric content, for all synthetic experimental diets used.
In the holidic media, amino acids are used to make up protein equivalents. To convert amino acids to protein equivalents, we used the molar quantities of nitrogen and the assumption that N makes up …
| Diet | Protein: carbohydrate equivalent | Sum mass of amino acids (g/l) | Equivalent protein (g/l) | Carbohydrate (g/l)† | Cholesterol (g/l) | Estimated caloric content (kcal/l) |
|---|---|---|---|---|---|---|
| 1 | 1:3.6 | 5.25 | 4.7 | 17.1 | 0 | 87.2 |
| 2 | 1:3.6 | 5.25 | 4.7 | 17.1 | 0.15 | 87.2 |
| 3 | 1:3.6 | 5.25 | 4.7 | 17.1 | 0.3 | 87.2 |
| 4 | 1:3.6 | 5.25 | 4.7 | 17.1 | 0.6 | 87.2 |
| 5 | 1:3.6 | 10.74 | 9.7 | 35 | 0 | 178.8 |
| 6 | 1:3.6 | 10.74 | 9.7 | 35 | 0.15 | 178.8 |
| 7 | 1:3.6 | 10.74 | 9.7 | 35 | 0.3 | 178.8 |
| 8 | 1:3.6 | 10.74 | 9.7 | 35 | 0.6 | 178.8 |
| 9 | 1:1.8 | 10.74 | 9.7 | 17.1 | 0 | 107.2 |
| 10 | 1:1.8 | 10.74 | 9.7 | 17.1 | 0.15 | 107.2 |
| 11* | 1:1.8 | 10.74 | 9.7 | 17.1 | 0.3 | 107.2 |
| 12 | 1:1.8 | 10.74 | 9.7 | 17.1 | 0.6 | 107.2 |
| 13 | 1:0.6 | 33.1 | 30 | 17.1 | 0 | 188.4 |
| 14 | 1:0.6 | 33.1 | 30 | 17.1 | 0.15 | 188.4 |
| 15 | 1:0.6 | 33.1 | 30 | 17.1 | 0.3 | 188.4 |
| 16 | 1:0.6 | 33.1 | 30 | 17.1 | 0.6 | 188.4 |
| 17 | 1:0.6 | 10.74 | 9.7 | 5.7 | 0 | 61.6 |
| 18 | 1:0.6 | 10.74 | 9.7 | 5.7 | 0.15 | 61.6 |
| 19 | 1:0.6 | 10.74 | 9.7 | 5.7 | 0.3 | 61.6 |
| 20 | 1:0.6 | 10.74 | 9.7 | 5.7 | 0.6 | 61.6 |
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* Standard diet.
† Carbohydrate is added to the diet as sucrose.
Additional files
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Supplementary file 1
Estimates from a linear mixed effects model to explain the effects of protein and carbohydrate on cumulative eggs laid per female, with replicate as a random effect.
Decreasing doses of carbohydrate and increasing doses of protein resulted in significantly increased egg production.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp1-v1.docx
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Supplementary file 2
Estimates from a linear mixed effects model to explain the effects of protein and carbohydrate on lifespan (median lifespan (days)), with vial as a random effect.
While variations in carbohydrate had no effect on lifespan, increasing doses of protein resulted in a significant change in lifespan. Visual inspection of the data agreed with our past experience with these diets (Piper et al., 2014; Piper, 2017) that the lifespan response was best modelled by the quadratic term for protein (Protein2) since lifespan peaked at our intermediate protein dose and fell away at both higher and lower doses. The quadratic term for Carbohydrate was thus also added to maintain balance in the model (Carbohydrate2). The interaction between protein and carbohydrate is not included in any of our analyses because these terms were not co-varied in a balanced way in our experimental design.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp2-v1.docx
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Supplementary file 3
Effects on median lifespan (days) of calories, cholesterol and diet type (a categorical variable indicating if either protein or carbohydrate was varied).
Cholesterol had a significant positive effect on median lifespan, while diet type had a significant effect on median lifespan. Calories had no significant effect on lifespan. Data were analysed using a linear model with mixed effects, with vial as a random effect.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp3-v1.docx
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Supplementary file 4
Effects on cumulative eggs per female of calories, cholesterol and diet type (a categorical variable indicating if either protein or carbohydrate was varied).
Cholesterol had a significant positive effect on cumulative eggs per female, while diet type had a significant effect on cumulative eggs per female. Calories had no significant effect on cumulative eggs per female. Data were analysed using a linear model with mixed effects, with vial as a random effect.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp4-v1.docx
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Supplementary file 5
Minimum adequate model describing the effects of protein, protein2 carbohydrate, carbohydrate2, cholesterol, cholesterol2 and, where appropriate, their interactive effects on median lifespan (days).
Data were analysed using a linear model with mixed effects, with vial as a random effect.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp5-v1.docx
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Supplementary file 6
Minimum adequate model describing the effects of protein, protein2 carbohydrate, carbohydrate2, cholesterol, cholesterol2 and, where appropriate, their interactive effects on cumulative eggs per female.
Data were analysed using a linear model with mixed effects, with vial as a random effect.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp6-v1.docx
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Supplementary file 7
Effects on cumulative eggs per female of P:C ratio, cholesterol, cholesterol2 and the interaction between P:C ratio and cholesterol.
Each of the main effects had a significant positive effect on egg production, and the amount of cholesterol significantly modified how P:C affected egg laying. Data were analysed using a linear model with mixed effects, with vial as a random effect.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp7-v1.docx
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Supplementary file 8
Effects on median lifespan (days) of cumulative eggs per female, cholesterol, cholesterol2 and the interaction between cumulative egg production and cholesterol.
Cumulative egg production and cholesterol had a significant positive effect on median lifespan, while cholesterol2 had a significant negative effect on median lifespan. Data were analysed using a linear model with mixed effects, with vial as a random effect.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp8-v1.docx
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Supplementary file 9
The relative proportions of each amino acid in the FLYaa amino acid mixture used in this study.
- https://cdn.elifesciences.org/articles/62335/elife-62335-supp9-v1.docx
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Transparent reporting form
- https://cdn.elifesciences.org/articles/62335/elife-62335-transrepform-v1.pdf
