Work

Removal of Exogenous Stimuli Reveals a Canalization of Circadian Physiology in a Vertically Migrating Copepod

Year: 2024

Type: article

Abstract: Diel rhythms are observed across taxa and are important for maintaining synchrony between the environment and organismal physiology. A striking example of this is the diel vertical migration undertaken by zooplankton, some of which, such as the 5 mm long copepod Pleuromamma xiphias, migrate hundreds of meters daily between the surface ocean and deeper waters. Some of the molecular pathways that underlie the expressed phenotype at different stages of this migration are entrained by environmental variables (e.g., photoperiod, food availability), while others are regulated by circadian clocks. To better understand which physiological processes are environmentally mediated versus under putative circadian clock control in P. xiphias, we compared proteomic profiles of free-living, in situ copepods to those incubated shipboard in the dark over 36 hours. The dark-incubated copepods shared some proteomic similarities to the ocean-caught copepods (i.e. increased carbohydrate metabolism at night). The most striking difference between the two groups was a clearer distinction between night and day proteomic profiles in incubated copepods, even in the absence of photoperiod and other environmental cues. This trend was reflected at the whole proteome level as well as in a targeted proteomics dataset where more proteins were differentially abundant in the incubated copepods than in the in situ. This pattern suggests that there is a canalization of rhythmic diel physiology in P. xiphias that reflects likely circadian clock control over diverse molecular pathways.

Source: Journal of Proteome Research

DOI: 10.1021/acs.jproteome.4c00086

Authors: Emma Timmins-Schiffman, Amy E. Maas, Rayhan Khanna, Leocadio Blanco-Bercial, Eric Huang, Brook L. Nunn