Opsin-based extraocular photoreception in holothurians

Ce mémoire s’intéresse à la perception de la lumière chez les concombres de mer (Holothuroidea, Echinodermata). Structurellement, ce travail comporte trois axes principaux : (i) l’identification par approche in silico des gènes d’opsines [acteurs moléculaires prototypiques de la perception de la lumière chez les bilatériens] chez les holothuries à partir de données génomiques ou transcriptomiques disponibles ; (ii) la localisation par une approche immunohistochimique des opsines ciliaire (opsine 1) et rhabdomérique (opsine 4) [deux types d’opsines homologues aux opsines visuelles de deutérostomiens et protostomiens, respectivement] dans les tissus de différentes espèces d’holothuries. Les structures photosensorielles plus spécialisées (cupules et ocelles) présentes chez l’ordredes Apodida ont particulièrement été envisagées. (iii) l’étude de l’effet de stimuli lumineux sur le comportement des concombres de mer. L’approche in silico nous a permis de mettre en évidence chez les holothuries la présence de six différents types d’opsines parmi les dix classes d’opsines ancestrales répertoriées chez les bilatériens. Parmi ces opsines figurent l’opsine ciliaire (opsine 1) et l’opsine rhabdomérique (opsine 4) que nous avons mises en évidence par immunohistochimie et immunofluorescence. Les opsines 1 et 4 ont été détectées dans le tégument, les papilles sensorielles cutanées, les podia et les tentacules chez les espèces H. forskali et H. scabra. Toutefois, un problème de spécificité d’anticorps a été identifié chez H. forskali et les marquages devront être vérifié dans le futur. En outre, nous avons mis en évidence la présence de ces deux types d’opsines dans les cupules sensorielles chez l’espèce Oestergrenia digitata. Ce qui suggère que ces structures, dont la fonction était jusqu’à présent inconnue, joueraient un rôle dans la perception de la lumière. Chez une autre espèce d’Apodida (Euapta godeffroyi) nous avons mis en évidence une forte immunoréactivité à l’opsine 1 dans les cellules neuroépithéliales ciliées qui forment l’ocelle. Ce qui confirme le rôle de ces ocelles dans la perception visuelle chez cette espèce. Les tests comportementaux menés chez l’espèce Holothuria forskali montrent un phototropisme négatif lorsque ces animaux sont exposés à des longueurs d’onde lumineuses courtes (bleu, vert) et ce malgré l’absence d’organe visuel spécialisé chez cette espèce. La présence d’opsines que nous avons détectées dans des structures telles que les papilles, les podia ou les tentacules permettrait une perception extraoculaire des stimuli lumineux. L’ espèce E. godeffroyi réagit très rapidement aux stimuli visuels de courte longueur d’onde (bleu, vert) par un comportement photophobe. La perception visuelle chez cette espèce semble être associée à la présence d’opsines dans les ocelles et le phototropisme négatif que nous avons observé est en parfaite adéquation avec le mode de vie nocturne de cette espèce.The present master thesis focuses on the perception of light in sea cucumbers (Holothuroidea, Echinodermata). Structurally, this work has three main axes: (i) the identification by in silico approach of opsin genes [prototypical molecular actors of light perception in bilaterians] in see cucumbers from genomic or transcriptomic data. (ii) the immunolocalization of ciliary (opsin 1) and rhabdomeric (opsin 4) opsins [two types of opsins homologous to deuterostomian and protostomian visual opsins, respectively] in tissues of different holothurian species. The specialized photosensory structures (cups and ocelli) present in the Apodida order were particularly considered. (iii) the study of the effect of light stimuli on the behavior of sea cucumbers. The in silico approach allowed us to identify six different types of opsins in sea cucumbers among the ten ancestral classes of opsins listed in bilaterians. Among these opsins are the ciliary opsin (opsin 1) and the rhabdomeric opsin (opsin 4) which we have identified by immunohistochemistry and immunofluorescence. Opsins 1 and 4 were detected in the integument, cutaneous sensory papillae, podia, and tentacles in H. forskali and H. scabra species. However, the antibody specificity problem of labeling was identified cutaneous and papillary in H. forskali and the labelings will need to be verified in the future. has encountered specificity problems and will need to be confirmed by in situ hybridization. In addition, we have demonstrated the presence of both types of opsins in the sensory cups of Oestergrenia digitata. This suggests that these structures, whose function was unknown until now, would play a role in light perception. In another species of Apodida (Euapta godeffroyi) we have demonstrated a strong immunoreactivity to opsin 1 in the ciliated neuroepithelial cells that form the ocelli. This confirms the role of these ocelli in visual perception in this species. Behavioral tests conducted in H. forskali show a negative phototropism when these animals are exposed to short wavelengths of light (blue, green) despite the absence of specialized visual organs in this species. The presence of opsins that we have detected in structures such as papillae, podia or tentacles would allow an extraocular perception of light stimuli. The species E. godeffroyi reacts quickly to visual stimuli of short wavelength (blue, green) by a photophobic behavior. The visual perception in this species seems to be clearly associated with the presence of opsins in the ocelli and the negative phototropism that we observed is in adequacy with the nocturnal lifestyle of this species

Multidimensional screening for predicting pain problems in adults : a systematic review of screening tools and validation studies

Screening tools allowing to predict poor pain outcomes are widely used. Often these screening tools contain psychosocial risk factors. This review (1) identifies multidimensional screening tools that include psychosocial risk factors for the development or maintenance of pain, pain-related distress, and pain-related disability across pain problems in adults, (2) evaluates the quality of the validation studies using Prediction model Risk Of Bias ASsessment Tool (PROBAST), and (3) synthesizes methodological concerns. We identified 32 articles, across 42 study samples, validating 7 screening tools. All tools were developed in the context of musculoskeletal pain, most often back pain, and aimed to predict the maintenance of pain or pain-related disability, not pain-related distress. Although more recent studies design, conduct, analyze, and report according to best practices in prognosis research, risk of bias was most often moderate. Common methodological concerns were identified, related to participant selection (eg, mixed populations), predictors (eg, predictors were administered differently to predictors in the development study), outcomes (eg, overlap between predictors and outcomes), sample size and participant flow (eg, unknown or inappropriate handling of missing data), and analysis (eg, wide variety of performance measures). Recommendations for future research are provided

Morphological study of the integument and corporal skeletal muscles of two psammophilous members of Scincidae (Scincus scincus and Eumeces schneideri)

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Protecting data privacy is key to a smart energy future

The ability to collect fine-grained energy data from smart meters has benefits for utilities and consumers. However, a proactive approach to data privacy is necessary to maximize the potential of these data to support low-carbon energy systems and innovative business model

Expression of Nestin, Vimentin, and NCAM by Renal Interstitial Cells after Ischemic Tubular Injury

This work explores the distribution of various markers expressed by interstitial cells in rat kidneys after ischemic injury (35 minutes) during regeneration of S3 tubules of outer stripe of outer medulla (OSOM). Groups of experimental animals (n = 4) were sacrificed every two hours during the first 24 hours post-ischemia as well as 2, 3, 7, 14 days post-ischemia. The occurrence of lineage markers was analyzed on kidney sections by immunohistochemistry and morphometry during the process of tubular regeneration. In postischemic kidneys, interstitial cell proliferation, assessed by 5-bromo-2′-deoxyuridine (BrdU) and Proliferating Cell Nuclear Antigen (PCNA) labeling, was prominent in outer medulla and reach a maximum between 24 and 72 hours after reperfusion. This population was characterized by the coexpression of vimentin and nestin. The density of -Neural Cell Adhesion Molecule (NCAM) positive interstitial cells increased transiently (18–72 hours) in the vicinity of altered tubules. We have also localized a small population of α-Smooth Muscle Actin (SMA)-positive cells confined to chronically altered areas and characterized by a small proliferative index. In conclusion, we observed in the postischemic kidney a marked proliferation of interstitial cells that underwent transient phenotypical modifications. These interstitial cells could be implicated in processes leading to renal fibrosis

Cytological analysis of integumentary and muscular adaptations in three sand-dwelling marine teleosts, Ammodytes tobianus (Ammodytidae), Gorgasia preclara (Congridae) and Heteroconger hassi (Congridae) (Teleostei; Actinopterygii)

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Comparative study of the visual system of two psammophilic lizards (Scincus scincus & Eumeces schneideri)

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étude de la photoréception des concombres de mer

peer reviewedIt has been known that echinoderms, despite lacking complex eye structures, exhibit photosensitivity mediated by opsins, photoreceptor proteins also found in other bilaterians. Recent studies on sea urchins, sea stars, and brittle stars, have revealed opsins in various body parts such as tube feet, spines, and the nervous system (Ullrich-Lüter et al., 2011; Delroisse et al., 2014). The eyespot located at the sea star arm tips has also been studied extensively. Some species have even demonstrated low-resolution extraocular spatial vision (e.g., Sumner-Rooney et al., 2020). However, photoreception in sea cucumbers has remained largely unexplored, with only sporadic data available, such as observations of species moving away from a light source or retracting their oral tentacles under strong light exposure. To fill this knowledge gap, we conducted a comprehensive investigation of sea cucumber photoreception using a multidisciplinary approach. Firstly, we analyzed genomes and transcriptomes of multiple holothuroid species, revealing the presence of six ancestral opsin types in this group. Secondly, we highlighted the expression of rhabdomeric opsins, commonly found in protostome eyes, in oral tentacles and tube feet of Holothuria (Panningothuria) forskali, a European species belonging to the Holothuriida order. Our investigation also focused on the Apodida order, a group of sea cucumbers with snake-shaped bodies lacking tube feet. Previous authors have proposed the presence of visual-like structures at the base of the tentacles and/or in association with the oral nerve ring in different species (e.g., Ludwig, 1889; Yamamoto & Yoshida, 1978). Our study revealed the expression of ciliary opsins, typically found in vertebrate eyes, in the neuroepithelial structures forming eyespots at the base of tentacles in the tropical species Euapta godeffroyi. We also detected the expression of ciliary opsins in the sensory cupules of Oestergrenia digitata, a burrowing European species. Until now, the functions of these cupules located on the inner surface of tentacles had remained unexplored. Finally, ethological tests conducted on both Holothuriida and Apodida species revealed that H.(P.) forskali and E. godeffroyi moved away from a light source, while Synapta maculata exhibited a movement toward it, specifically in response to blue and green lights. These findings provide new insights into the mechanisms and evolution of photoreception in sea cucumbers

Nouvelles données sur la diversité des photorécepteurs chez les deux groupes d'Echinodermes : Crinoïdes et Concombres de mer

editorial reviewedEchinoderms are marine invertebrates (comprising starfishes and sea urchins) which exhibit an important light sensitivity despite lacking complex photosensory organ. This extraocular photoreception is allowed by opsins (typical photoreceptor proteins) present in different part of their bodies like spines and tube feet as several studies have revealed in sea urchins, sea stars and in brittle stars. Moreover, Echinoderms possess a remarkable wide diversity of these photoreceptors with a preservation of seven out of the nine ancestral bilaterian-type opsin lineages. This makes them good models to study the evolution of light perception and opsin diversity in deuterostomes. However, the photoreception has been remained largely understudied in two major echinoderm classes: sea cucumbers (Holothuroidea) and feather stars (Crinoidea). Nevertheless, the investigation of these two groups remains of great interest, on the one hand because of the unusual bilateral derived morphology in the case of holothurians, and on the other because of the privileged basal position in the echinoderm phylogeny for crinoids. To investigate the photoreception in these groups, we used a multidisciplinary approach, including behavioral experiments, in silico gene searching, as well as morpho-functional analyses. The ethological tests conducted on several sea cucumbers have shown both negative and positive phototaxis according to species, specifically for shorter wavelengths corresponding to blue and green lights. On the other hand, the shallow-water European crinoid Antedon bifida exhibits a negative phototactic behavior for both short (blue light) and long (red light) wavelengths. The in silico analysis of genomes and transcriptomes from various sea cucumber species have shown a similar high diversity of ancestral bilaterian opsin lineages, as observed in other echinoderms. In contrast, the genome of our model European crinoid Antedon bifida exhibited only three rhabdomeric opsin genes. This reduction in opsin diversity suggests maybe a pronounced specialization in the photoreception of feather stars or at least for the Antedonid family. Finaly, the opsin localisations have been highlighted by immunodetection in different tissues of holothurian and crinoid species. In the European sea cucumber Holothuria forskali, the expression of rhabdomeric opsins was specifically detected in feeding oral tentacles, radial nerves, and locomotory tube feet. We have also focused on the Apodida order (a group of snake-shaped sea cucumbers). Our study demonstrated the expression of a ciliary opsin in the photo-sensory neuroepithelial structures which form eyespots at the base of each oral tentacle of the large tropical species Euapta godeffroyi. Additionally, we have also detected ciliary opsins in the sensory cupules located on the inner surface of tentacles in a small burrowing eye-less Apodida species Oestergrenia digitata. In the feather star A. bifida, two rhabdomeric opsins are expressed in various nerve plexus, as well as in the tube feet of ambulacral grooves