Transcriptome and Peptidome Characterisation of the Main Neuropeptides and Peptidic Hormones of a Euphausiid: The Ice Krill, Euphausia crystallorophias

Abstract

BackgroundThe Ice krill, Euphausia crystallorophias is one of the species at the base of the Southern Ocean food chain. Given their significant contribution to the biomass of the Southern Ocean, it is vitally important to gain a better understanding of their physiology and, in particular, anticipate their responses to climate change effects in the warming seas around Antarctica.Methodology/Principal FindingsIllumina sequencing was used to produce a transcriptome of the ice krill. Analysis of the assembled contigs via two different methods, produced 36 new pre-pro-peptides, coding for 61 neuropeptides or peptide hormones belonging to the following families: Allatostatins (A, B et C), Bursicon (α and β), Crustacean Hyperglycemic Hormones (CHH and MIH/VIHs), Crustacean Cardioactive Peptide (CCAP), Corazonin, Diuretic Hormones (DH), the Eclosion Hormone (EH), Neuroparsin, Neuropeptide F (NPF), small Neuropeptide F (sNPF), Pigment Dispersing Hormone (PDH), Red Pigment Concentrating Hormone (RPCH) and finally Tachykinin. LC/MS/MS proteomics was also carried out on eyestalk extracts, which are the major site of neuropeptide synthesis in decapod crustaceans. Results confirmed the presence of six neuropeptides and six precursor-related peptides previously identified in the transcriptome analyses.ConclusionsThis study represents the first comprehensive analysis of neuropeptide hormones in a Eucarida non-decapod Malacostraca, several of which are described for the first time in a non-decapod crustacean. Additionally, there is a potential expansion of PDH and Neuropeptide F family members, which may reflect certain life history traits such as circadian rhythms associated with diurnal migrations and also the confirmation via mass spectrometry of several novel pre-pro-peptides, of unknown function. Knowledge of these essential hormones provides a vital framework for understanding the physiological response of this key Southern Ocean species to climate change and provides a valuable resource for studies into the molecular phylogeny of these organisms and the evolution of neuropeptide hormones.

Population Genomics of Marine Zooplankton

“…Transcriptomic analysis has indicated the presence of multi-copy gene families originating from multiple duplications of an ancestral gene in copepods (Lenz et al 2014;Yang et al 2014), euphausiids (Toullec et al 2013;Sales et al 2017), and pteropods (Maas et al 2015;Thabet et al 2017).…”

Egg-Laying in the Cuttlefish Sepia officinalis

“…They are usually C-terminally amidated neuropeptides in arthropods [21][22][23][24], as well as in mollusks [14,[25][26][27], whereas the cuttlefish preprohormone predicted three nonamidated peptides confirmed by nLC-MS/MS analysis.…”

In silico characterization of the neuropeptidome of the Western black widow spider Latrodectus hesperus

“…Christie et al, 2013bChristie et al, , 2014aLenz et al, 2014), including neuropeptide precursors (e.g. Christie 2008aChristie ,b, 2014aChristie et al, 2008Christie et al, , 2010aChristie et al, , 2011aChristie et al, ,b, 2013aGard et al, 2009;Ma et al, 2009Ma et al, , 2010Toullec et al, 2013;Yan et al, 2012). Once identified, the mature structures of individual peptide isoforms can be predicted from the transcriptome sequences via simple workflows using freeware.…”

“…Audsley and Weaver, 2006;Boerjan et al, 2010;Christie, 2008aChristie, , 2014aChristie et al, 2008Christie et al, , 2010aChristie et al, , 2013aDircksen et al, 2011;Fu et al, 2005;Gard et al, 2009;Hauser et al, 2010;Hewes and Taghert, 2001;Hui et al, 2012Hui et al, , 2013Hummon et al, 2006;Huybrechts et al, 2003Huybrechts et al, , 2010Li et al, 2008Li et al, , 2003Ma et al, 2008Ma et al, , 2009Ma et al, , 2010Tanaka et al, 2014;Toullec et al, 2013;Vanden Broeck, 2001;Ventura et al, 2014;Verleyen et al, 2004;Yan et al, 2012;Zoephel et al, 2012), with only limited work done on members of the Chelicerata (e.g. Christie, 2008b;Christie et al, 2011a;Donohue et al, 2010;Neupert et al, 2009;Veenstra et al, 2012).…”