Biology subjects

Delroisse, J.

Publications and source records attributed to Delroisse, J..

3 recordsLinked to original sources

bioRxiv2018

De novo Transcriptome Analyses Provide Insights into Opsin-based Photoreception in the Lantern shark Etmopterus spinax

The velvet belly lantern shark (Etmopterus spinax) is a small deep-sea shark commonly found in the Easter Atlantic and the Mediterranean Sea. In this study, paired-end illumina HiSeqTM technology has been employed to analyse transcriptome data from eye and ventral skin tissues of the lantershark species. About 64 and 49 million Illumina reads were generated from skin and eyetissues respectively. The assembly allowed us to predict 119,749 total unigenes including 94,569 for the skin transcriptome and 94,365 for the eye transcriptome while 74,753 were commonly found in both transcriptomes. Among unigenes, 60,322 sequences were annotated using classical public databases. The assembled and annotated transcriptomes provide a valuable resource for further understanding of the shark biology. We identified potential \"light-interacting toolkit\" genes including multiple genes related to ocular and extraocular light perception processes such as opsins. In particular, a single rhodopsin gene mRNA and its potentially associated peropsin were only detected in the eye transcriptome confirming a monochromatic vision of the lantern-shark. Conversely, an encephalopsin mRNA was mainly detected in the skin transcriptome. The encephalopsin was immunolocalized in various shark tissues confirming its wide expression in the shark skin and pinpointing a possible functional relation with the photophore, i.e. epidermal light organs. We hypothesize that extraocular photoreception might be involved in the bioluminescence control possibly acting on the shutter opening and/or the photocyte activity itself.

evolutionary biology↗

bioRxiv2018

Thioredoxins induce oocyte maturation in holothuroids (Echinodermata)

Chromatographic fractions of a rough extract of echinoid spawn (REES) has been demonstrated to efficiently induce oocyte maturation in aspidochirote holothuroids. The method is so efficient that it is now used in holothuriculture to get fertilised eggs even outside the reproductive period of the aquacultured species. We here isolate and identify from echinoid spawns the molecule responsible for the induction of the oocyte maturation in the Mediterranean holothuroid Holothuria tubulosa and the Indo-Pacific Holothuria scabra. The use of proteinase K and dialysing membranes indicates that the active molecule is a protein with a molecular weight superior to 12,000 kDa. The active molecule has been isolated on G-100 Sephadex chromatography column. Active chromatographic fractions include seven proteins identified with nanoLC-MS/MS technique. One of them, identify as a thioredoxin-2 and to which the name Trx-REES has been given, leads up to levels of maturation similar to those obtained with the REES and with a commercial thioredoxin extracted from Escherichia coli. Occurrence of thioredoxin in REES was confirmed by immunoblot analysis, and the maturation-inducing properties of thioredoxin were positively checked in using anti-thioredoxin antibodies. A peptide of 6 AAs corresponding to the active site of Trx-REES, composed of WCNPCK, was synthesised and its efficiency in holothuroid oocyte maturation tested. At some concentrations, the peptide was 1.2 times more active than the REES.

zoology↗

bioRxiv2017

Ophiuroid Phylotranscriptomics Enables Discovery Of Novel Echinoderm Representatives Of Bilaterian Neuropeptide Families And Reconstruction Of Neuropeptide Precursor Evolution Over ~270 Million Years

BackgroundNeuropeptides are a diverse class of intercellular signaling molecules that mediate neuronal regulation of many physiological and behavioural processes, including feeding, reproduction and locomotion. Recent advances in genome/transcriptome sequencing are enabling identification of neuropeptide precursor proteins in species from a growing variety of animal taxa, providing new insights into the evolution of neuropeptide signaling. Here we report a phylo-transcriptomic analysis of neuropeptide precursors in over fifty species of brittle stars (Class Ophiuroidea; Phylum Echinodermata).\n\nResultsDetailed analysis of transcriptome sequence data from three brittle star species, Ophionotus victoriae, Amphiura filiformis and Ophiopsila aranea, enabled the first comprehensive identification of neuropeptide precursors in ophiuroids. Representatives of over thirty bilaterian neuropeptide precursor families were identified, some of which occur as paralogs (e.g. thyrotropin-releasing hormone, corticotropin-releasing hormone, cholecystokinin, somatostatin and pedal peptide). Furthermore, homologs of endothelin/CCHamide, eclosion hormone, neuropeptide-F/Y and nucleobinin/nesfatin were discovered here in a deuterostome/echinoderm for the first time. The majority of ophiuroid neuropeptide precursors contain a single copy of a neuropeptide, but several precursors comprise multiple copies of identical or non-identical, but structurally-related, neuropeptides. Here we performed an unprecedented investigation of the evolution of neuropeptide copy-number over a period of ~270 million years by analysing sequence data from over fifty ophiuroid species, with reference to a robust phylogeny. Interestingly, the number of neuropeptide copies in the majority of precursors was constant across all the species examined, but examples of clade-specific losses/gains of neuropeptides were also observed.\n\nConclusionsWe report here the most comprehensive analysis to date of neuropeptide precursors in the phylum Echinodermata, with novel representatives of several bilaterian neuropeptide families discovered for the first time in echinoderms. Furthermore, analysis of precursor proteins comprising multiple copies of identical or related neuropeptides across ~270 million years of ophiuroid evolution indicates that the composition of neuropeptide \"cocktails\" is functionally important, but with plasticity over long evolutionary time scales.

neuroscience↗