%0 Journal Article %J Chem Senses %D 2021 %T Exploration of chemosensory ionotropic receptors in cephalopods: the IR25 gene is expressed in the olfactory organs, suckers, and fins of Sepia officinalis. %A Aude Andouche %A Valera, Stéphane %A Sébastien Baratte %K Animals %K Cephalopoda %K Phylogeny %K Receptors, Ionotropic Glutamate %K Receptors, Odorant %K Sepia %K Smell %X

While they are mostly renowned for their visual capacities, cephalopods are also good at olfaction for prey, predator, and conspecific detection. The olfactory organs and olfactory cells are well described but olfactory receptors-genes and proteins-are still undescribed in cephalopods. We conducted a broad phylogenetic analysis of the ionotropic glutamate receptor family in mollusks (iGluR), especially to identify IR members (Ionotropic Receptors), a variant subfamily whose involvement in chemosensory functions has been shown in most studied protostomes. A total of 312 iGluRs sequences (including 111 IRs) from gastropods, bivalves, and cephalopods were identified and annotated. One orthologue of the gene coding for the chemosensory IR25 co-receptor has been found in Sepia officinalis (Soff-IR25). We searched for Soff-IR25 expression at the cellular level by in situ hybridization in whole embryos at late stages before hatching. Expression was observed in the olfactory organs, which strongly validates the chemosensory function of this receptor in cephalopods. Soff-IR25 was also detected in the developing suckers, which suggests that the unique « taste by touch » behavior that cephalopods execute with their arms and suckers share features with olfaction. Finally, Soff-IR25 positive cells were unexpectedly found in fins, the two posterior appendages of cephalopods, mostly involved in locomotory functions. This result opens new avenues of investigation to confirm fins as additional chemosensory organs in cephalopods.

%B Chem Senses %V 46 %8 2021 01 01 %G eng %R 10.1093/chemse/bjab047 %0 Journal Article %J Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology %D 2018 %T Digestive enzyme ratios are good indicators of hatchling yolk reserve and digestive gland maturation in early life stages of cuttlefish Sepia officinalis L.: application of these new tools in ecology and aquaculture %A Safi, Georges %A Anne-Sophie Martinez %A Le Pabic, Charles %A Le Bihan, E %A Jean-Paul Robin %A Koueta, Noussithé %K Acid Phosphatase %K alkaline phosphatase %K anatomy and histology %K animal %K Animals %K Aquaculture %K cathepsin %K Cathepsins %K cuttlefish %K Gastrointestinal Tract %K Physiology %K Sepia %K Trypsin %X In Sepia officinalis (Linnaeus, 1758), the digestive gland matures during the first month post-hatching, while a shift from intracellular acid to extracellular alkaline digestion occurs. The purpose of this study was to investigate the possibility of using enzymatic ratios for the description of digestive system maturation in early life stages of S. officinalis. Second, it is intended to apply these new tools as eco-physiological indicators for understanding the impact of cuttlefish eggs’ life history from different spawning sites of the English Channel on digestive performance of juveniles. An experimental rearing was performed over 35 days after hatching (DAH) on juveniles from wild collected eggs in 2010 and 2011. Four digestive enzyme activities and their ratios [i.e., trypsin, cathepsin, acid (ACP), and alkaline (ALP) phosphatase, ALP/ACP, and trypsin/cathepsin] were studied along with histological features (e.g., internal yolk surface and digestive gland development). The two enzyme ratios were good indicators of digestive system maturation allowing the study of the digestive gland’s development. They were highly correlated to juveniles’ weight increase and histological features of the gland in early DAH. These ratios described more accurately the shift occurring between the intracellular acid and the extracellular alkaline modes of digestion in S. officinalis and were more specific than separated enzyme activities. Their application as eco-physiological tools revealed that enzyme ratios reflected yolk content and digestive gland development in new hatching juveniles. Finally, ALP/ACP ratio was shown to be a powerful tool to describe growth performance of S. officinalis which is useful for aquaculture optimization. © 2017, Springer-Verlag GmbH Germany. %B Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology %V 188 %P 57-76 %G eng %U https://link.springer.com/article/10.1007%2Fs00360-017-1115-4 %R 10.1007/s00360-017-1115-4