Info

Fully fed flies

Fully fed flies

Dietary restricted flies
Age

Figure 22.1. (A) Age-specific mortality trajectories in Drosophila subjected to different dietary regimes. Dietary restriction lowers initial mortality rate (intercept) but does not affect the rate of increase (slope).c (B) Rapid adjustment in mortality trajectories after changes in diet regime (post-switching trajectories are shown in solid lines; the trajectories in Figure 22.1-A are shown in dashed lines). (i) Switching from fully fed to dietary restriction diet; (ii) switching from dietary restriction to fully fed diet. Subsequent mortality trajectories after the diet switch are not affected by the previous dietary experiences, and only reflect the current dietary status. (Mair et al., 2003). Figures re-drawn from (Mair et al., 2003), with permission.

Figure 22.1. (A) Age-specific mortality trajectories in Drosophila subjected to different dietary regimes. Dietary restriction lowers initial mortality rate (intercept) but does not affect the rate of increase (slope).c (B) Rapid adjustment in mortality trajectories after changes in diet regime (post-switching trajectories are shown in solid lines; the trajectories in Figure 22.1-A are shown in dashed lines). (i) Switching from fully fed to dietary restriction diet; (ii) switching from dietary restriction to fully fed diet. Subsequent mortality trajectories after the diet switch are not affected by the previous dietary experiences, and only reflect the current dietary status. (Mair et al., 2003). Figures re-drawn from (Mair et al., 2003), with permission.

This study also suggests that dietary restriction does not affect irreversible, time-dependent accumulation of damage because the mortality was rapidly and completely reversed when the dietary restriction was removed (and vice versa). Thus, the effect of diet on mortality rate is only real-time, and not affected by past history (Mair et al., 2003). Examining the reversibility of a treatment is therefore particularly informative, and it will be enlightening to conduct this type of treatment-switching experiment in other experimental models that extend lifespan. However, it is debatable whether this response is unique to flies (Partridge et al., 2005). Similar demographic studies in mammals have not been performed to clarify this issue, perhaps due to a difficulty in conducting the study involving a large number of animals.

Next, microarray analysis of gene expression in response to dietary restriction showed that genes regulating cell growth, metabolism and reproduction were down regulated (Pletcher et al., 2002). However, there are many other molecular, biochemical and physiological studies that can be performed on the Drosophila dietary restriction model, as in the case of rodent models.

Was this article helpful?

0 0
Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

Get My Free Ebook


Post a comment