Mechanisms of Desiccation Tolerance: Themes and Variations in Brine Shrimp, Roundworms, and Tardigrades.

Jonathan D Hibshman,Bob Goldstein,James S Clegg

doi:10.3389/fphys.2020.592016

Abstract

Water is critical for the survival of most cells and organisms. Remarkably, a small number of multicellular animals are able to survive nearly complete drying. The phenomenon of anhydrobiosis, or life without water, has been of interest to researchers for over 300 years. In this review we discuss advances in our understanding of protectants and mechanisms of desiccation tolerance that have emerged from research in three anhydrobiotic invertebrates: brine shrimp (Artemia), roundworms (nematodes), and tardigrades (water bears). Discovery of molecular protectants that allow each of these three animals to survive drying diversifies our understanding of desiccation tolerance, and convergent themes suggest mechanisms that may offer a general model for engineering desiccation tolerance in other contexts.

Highlights

One study using RNAi knockdown revealed that a group 1 late embryogenesis abudant (LEA) protein is necessary for desiccation tolerance in Artemia cysts (Toxopeus et al, 2014)
We focus on Artemia, C. elegans, and tardigrades because there is some overlap in features of desiccation tolerance between these organisms, and there are meaningful differences in survival strategies
Heterologous expression in cultured human cells, a similar approach to that used by Artemia researchers, was used along with immunolocalization in tardigrades to determine the subcellular localization of a group 3 late embryogenesis abudant (LEA) protein of Ramazzottius varieornatus, RvLEAM

Summary

Introduction

One study using RNAi knockdown revealed that a group 1 LEA protein is necessary for desiccation tolerance in Artemia cysts (Toxopeus et al, 2014). Folding into alpha helices during desiccation (or similar experimentally simulated conditions) has proven to be a common attribute of a variety of LEA proteins and model peptides from animals including nematodes and Artemia (Tolleter et al, 2007; Li and He, 2009; Boswell et al, 2014a; Hand and Menze, 2015; LeBlanc et al, 2019).

Results

Conclusion