NMR Profiling of Metabolites in Larval and Juvenile Blue Mussels (Mytilus edulis) under Ambient and Low Salinity Conditions

Abstract

Blue mussels (Mytilus edulis) are ecologically and economically important marine invertebrates whose populations are at risk from climate change-associated variation in their environment, such as decreased coastal salinity. Blue mussels are osmoconfomers and use components of the metabolome (free amino acids) to help maintain osmotic balance and cellular function during low salinity exposure. However, little is known about the capacity of blue mussels during the planktonic larval stages to regulate metabolites during osmotic stress. Metabolite studies in species such as blue mussels can help improve our understanding of the species’ physiology, as well as their capacity to respond to environmental stress. We used 1D 1H nuclear magnetic resonance (NMR) and 2D total correlation spectroscopy (TOCSY) experiments to describe baseline metabolite pools in larval (veliger and pediveliger stages) and juvenile blue mussels (gill, mantle, and adductor tissues) under ambient conditions and to quantify changes in the abundance of common osmolytes in these stages during low salinity exposure. We found evidence for stage- and tissue-specific differences in the baseline metabolic profiles of blue mussels, which reflect variation in the function and morphology of each larval stage or tissue type of juveniles. These differences impacted the utilization of osmolytes during low salinity exposure, likely stemming from innate physiological variation. This study highlights the importance of foundational metabolomic studies that include multiple tissue types and developmental stages to adequately evaluate organismal responses to stress and better place these findings in a broader physiological context.

Time‐course changes in the regulation of ions and amino acids in the hard clam Meretrix lusoria upon lower salinity challenge

“…Our results further indicated that the contents of glutamate, glycine, alanine, and/or aspartate were also downregulated upon low‐salinity challenge, which is consistent with the findings in other bivalves when transferred to lower salinities. For example, the downregulated contents of alanine and glycine have been reported in the gill and mantle of juvenile blue mussel ( Mytilus edulis ) when transferred from 32‰ to 20‰ SW (May et al, 2017). In addition, the contents of other FAAs, such as glutamate, glycine, alanine, and aspartate, have also been observed to be downregulated in the mantle of the Pacific oyster after transfer to 50% seawater (Hosoi et al, 2003).…”

Marine Metabolomics: a Method for Nontargeted Measurement of Metabolites in Seawater by Gas Chromatography–Mass Spectrometry

“…For instance, in terrestrial and limnic systems, researchers used exometabolomics to study soil organic matter cycling (6, 7), overflow metabolism of cultivable microorganisms (8, 9), and chemical ecology of the environment (10, 11). While intracellular metabolomic analyses of tissues from marine microbial cells to invertebrates are becoming increasingly more common (12–14), the defining characteristic of marine habitats, i.e., high salt concentration, limits exometabolomic analyses of the oceans to studies that require salt removal prior to metabolite extraction (10, 15, 16).…”

Polyps of the Jellyfish Aurelia aurita Are Unaffected by Chronic Exposure to a Combination of Pesticides

“…Osmoconformers are organisms that maintain an osmotic pressure equivalent to that of the external environment using organic osmolytes like taurine, betaine, and homarine (Yancey 2005). These osmolytes have been detected in several marine invertebrates such as polychaetes ( Glycera ), snails ( Mitrella carinata ; Yancey 2005), mussels ( Mytilus edulis ; Tuffnail et al 2009; May et al 2017), and jellyfish (Boco et al 2019; Stabili et al 2019). These specific osmolytes were indeed present at relatively high abundances in jellyfish polyps, but no differences were observed due to pesticide exposure in the present study.…”