Caenorhabditis elegans Battling Starvation Stress: Low Levels of Ethanol Prolong Lifespan in L1 Larvae

Paola V Castro,Shilpi Khare,Brian D Young,Steven G Clarke,Shree Ram Singh

doi:10.1371/journal.pone.0029984

Abstract

The nematode Caenorhabditis elegans arrests development at the first larval stage if food is not present upon hatching. Larvae in this stage provide an excellent model for studying stress responses during development. We found that supplementing starved larvae with ethanol markedly extends their lifespan within this L1 diapause. The effects of ethanol-induced lifespan extension can be observed when the ethanol is added to the medium at any time between 0 and 10 days after hatching. The lowest ethanol concentration that extended lifespan was 1 mM (0.005%); higher concentrations to 68 mM (0.4%) did not result in increased survival. In spite of their extended survival, larvae did not progress to the L2 stage. Supplementing starved cultures with n-propanol and n-butanol also extended lifespan, but methanol and isopropanol had no measurable effect. Mass spectrometry analysis of nematode fatty acids and amino acids revealed that L1 larvae can incorporate atoms from ethanol into both types of molecules. Based on these data, we suggest that ethanol supplementation may extend the lifespan of L1 larvae by either serving as a carbon and energy source and/or by inducing a stress response.

Highlights

The nematode worm Caenorhabditis elegans is a powerful model organism for aging studies due to its short generation time and lifespan [1,2]
We found that starved wild-type L1 larvae incubated in M9 medium live about 15 days (Fig. 1, panel A), while larvae incubated in M9 medium supplemented with cholesterol dissolved in ethanol live about 30 days, or about twice as long
We demonstrate that these larvae can take up and incorporate ethanol into their fatty acids and amino acids

Summary

Introduction

The nematode worm Caenorhabditis elegans is a powerful model organism for aging studies due to its short generation time and lifespan [1,2]. Survival under conditions of stress can be enhanced by entering alternate larval stages, including diapauses in L1 larvae [3,4,5], dauer larvae [6], and L4 larvae [7]. In these alternate larval stages, worms are more stress resistant and have enhanced lifespans [3,7,8]. Dauer larvae are more resistant to oxidative [9], osmotic [10] and hypoxic stress [11]

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Results

Conclusion