Insights Into the Hypometabolic Stage Caused by Prolonged Starvation in L4-Adult Caenorhabditis elegans Hermaphrodites.

E. Carranza-García,Rosa E. Navarro

doi:10.3389/fcell.2020.00124

E. Carranza-García, Rosa E. Navarro

Open Access

https://doi.org/10.3389/fcell.2020.00124

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Abstract

Animals alter their reproductive cycles in response to changing nutritional conditions, to ensure that offspring production only occurs under favorable circumstances. These adaptive strategies include reversible hypometabolic states of dormancy such as “arrest” and “diapause.” The free-living nematode Caenorhabditis elegans can arrest its life cycle during some larval stages without modifying its anatomy and physiology until conditions improve but it can also modify its morphological and physiological features to cope with harsh conditions and transition into diapause. The well-defined “dauer” diapause was described more than 40 years ago and has been the subject of comprehensive investigations. The existence of another hypometabolic state, termed adult reproductive diapause (ARD), has been debated after it was first described 10 years ago. Here, we review the current knowledge regarding the effect of food deprivation during the pre-reproductive larval and adult stages on overall organismal homeostasis, highlighting the implications on germ cell maintenance and fertility preservation.

Highlights

All animals experience variations in food availability and must adjust their metabolism to survive under harsh conditions
Because there exist some discrepancies in the results obtained from similar experiments, it is of great significance to establish general considerations when studying this hypometabolic state
Published works have focused on both soma and germline responses to prolonged starvation of L4 and adult animals, while other works have focused mainly on the soma response; still others have focused exclusively on the germline response

Summary

Introduction

All animals experience variations in food availability and must adjust their metabolism to survive under harsh conditions. Biological processes can be slowed or arrested, affecting development, reproduction and gene expression, which in turn results in finely regulated systemic adaptations (Padilla and Ladage, 2012; Baugh, 2013). Many metazoans, ranging from worm to mammals, experience hypometabolic states such as developmental arrest, diapause, quiescence, and hibernation. The nematode Caenorhabditis elegans can experience three different types of hypometabolic states throughout its life cycle; embryo suspended animation, larval arrest and diapause. Embryo suspended animation is a reversible hypometabolic state caused by oxygen deprivation and it is characterized by a reduction in the ATP/ADP ratio, which in turn causes an arrest of the cell cycle in the blastomeres (Padilla and Ladage, 2012).

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