In 2013, neurobiologist Kristin Tessmar-Raible and her colleagues published some of the most compelling evidence of a molecular moon clock in an ocean creature. They studied the marine bristle worm Platynereis dumerilii, which looks like an amber centipede with tiny feathered oars running the length of its body. In the wild, the bristle worm lives on algae and rocks, spinning silk tubes for shelter. While reading studies from the 1950s and ’60s, Tessmar-Raible learned that some wild bristle worm populations achieve maximal sexual maturity just after the new moon, swimming to the ocean surface and twirling in circles in a kind of whirling dervish nuptial dance. The studies suggested that changing levels of moonlight orchestrated this mating ritual. “At first I thought this was really crazy in terms of biology,” says Tessmar-Raible, who notes that she grew up far from the ocean, “but then I started talking to colleagues in marine biology and realized that this might not be so uncommon.”

To learn more, Tessmar-Raible and her colleagues kept bristle worms in plastic boxes, feeding them spinach and fish food, and simulating typical and aberrant moon cycles with an array of standard light bulbs and LEDs. Worms raised in perpetual light or in entirely moonless day-night cycles never displayed reproductive rhythms. But worms reared with periodic nocturnal illumination synced their spawning rituals to the phases of their artificial moon. As suggested by earlier studies, Tessmar-Raible found light-sensitive neurons in the worms’ forebrains. And genetic sequencing revealed that the bristle worm has its own versions of essential molecular clock genes found in terrestrial insects and vertebrates. Tessmar-Raible’s conclusion is that the worms have a robust lunar clock analogous to the more familiar sun-synced circadian clock. “This is an endogenous oscillator,” she says. “Something in the body preserves the memory of those nocturnal illuminations.”

In similar studies, Oren Levy and his colleagues collected pieces of living corals from Heron Island reef and housed them in large outdoor aquaria, some of which were exposed to ambient sunshine and moonlight, some shaded at night to block all moonlight, and some subjected to dim artificial light from sunset to midnight and then kept in the dark until sunrise. Each day for eight days before the estimated night of mass spawning, the researchers collected bits of corals from the different aquaria and analyzed the activity of their genes. The corals in natural conditions spawned as predicted and expressed many genes only during or just before releasing their gametes. Corals subjected to artificial light and deprived of moonlight displayed anomalous gene expression and failed to release their gametes.

 —   The Lunar Sea

Hi! I'm relatively new to this fandom and Tumblr, but I found you via AO3 and I just have to say I love you the little community you're building here. The collaborative storytelling is amazing! I do have a prompt though. I've seen some atypical genitalia for Dream and I love it, but I feel like we're ignoring a very interesting niche here: a genderfluid Hob getting to express and explore themself via the Dreaming and with the Shaper of Forms as a guide.

This is such a kind and sweet message, thank you so much!! I'm thrilled that you're enjoying the vibes here, that makes me so happy.

Genderfluid Hob is an amazing concept. Imagine how Dream would absolutely dote on Hob in the dreaming, giving them the most glorious selection of forms. Anything Hob can imagine is possible. At first, they're just thrilled to have the opportunity to switch between a more masculine or feminine presentation whenever they choose. Being able to switch from cock to cunt literally in the middle of sex is the most affirming and fantastic experience!! Or they can choose both. Or neither. Dream is eager to show Hob that they can be absolutely anything in his realm.

Cue explorations of plant genitals (Hob has always been fascinated by the way a flower can be both male and female), the forms of deep sea creatures yet to even be discovered by humans, and some stuff that Hob is 90% sure that Dream is just making up. It's awesome. They have never been so happy. Because they can have sex with Dream when both of them are swimming deep in the ocean as Platynereis dumerilii (marine bristle worms). Or as a pair of meteoroids. It's all fantastic. Waking up is difficult, sometimes, but Dream is always there with a kiss and one of his tiny smiles. Hob is always so grateful for the fact that they can explore this part of themself with someone who loves them so faithfully.

And tomorrow night will be even more fantastic. Hob can hardly wait.

Elongation capacity of polyunsaturated fatty acids in the annelid Platynereis dumerilii

BioRxiv: http://dlvr.it/T4B38d

Platynereis dumerilii, vous prendrez bien un petit ver

See on Scoop.it - EntomoScience

... Une BD tournée intégralement dans les locaux d’un authentique centre de recherche parisien. Cerise sur le gâteau, elle coïncide quasi-parfaitement à la réalité puisqu’au moment même où vous allez la lire, je serai probablement en train de m’occuper de vrais élèves de terminale Scientifique, venus visiter mon laboratoire pour la fête de la science.

  Strange Stuff And Funky Things

Par Vran, jeudi 13 octobre 2011

  "Alors, il est pas aux petits oignons le Vran ? (Les images affichées ci dessous ne sont que des miniatures, n’hésitez pas à cliquer dessus pour accéder aux planches taille réelles pour plus de lisibilité)"

Fast Cycling Culture of the Marine Annelid Platynereis dumerilii

http://dlvr.it/SnMt4D

Study reveals single gene ‘invented’ haemoglobin several times - health

Study reveals single gene ‘invented’ haemoglobin several times – health

Thanks to the marine worm Platynereis dumerilii, an animal whose genes have evolved very slowly, a team of scientists have shown that while haemoglobin appeared independently in several species, it actually descends from a single gene transmitted to all by their last common ancestor. The findings of the study by scientists from CNRS, Universite de Paris and Sorbonne Universite, in association…

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One gene is responsible for lots of types of hemoglobin.

One gene is responsible for lots of types of hemoglobin.

Thanks to the marine worm Platynereis dumerilii, an animal whose genes have evolved very slowly, scientists from CNRS, Université de Paris and Sorbonne Université, in association with others at the University of Saint Petersburg and the University of Rio de Janeiro, have shown that while haemoglobin appeared independently in several species, it actually descends from a single gene transmitted to…

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Thanks to the marine worm Platynereis dumerilii, an animal whose genes have evolved very slowly, scientists have shown that while haemoglobin appeared independently in several species, it actually descends from a single gene transmitted to all by their last common ancestor.

A single gene 'invented' haemoglobin several times -- ScienceDaily

A single gene ‘invented’ haemoglobin several times — ScienceDaily

Thanks to the marine worm Platynereis dumerilii, an animal whose genes have evolved very slowly, scientists from CNRS, Université de Paris and Sorbonne Université, in association with others at the University of Saint Petersburg and the University of Rio de Janeiro, have shown that while haemoglobin appeared independently in several species, it actually descends from a single gene transmitted to…

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L’ensemble des connexions nerveuses d’un cerveau de larve de drosophile a été cartographié

See on Scoop.it - EntomoNews

À l'aide de nombreuses images de microscopie électronique et d'une reconstruction assistée par ordinateur, une équipe de l'université de Cambridge a pu établir le connectome de la larve de drosophile, c'est-à-dire reconstituer l'intégralité des 544 000 synapses unissant ses 3013 neurones !

  Publié le 10.02.23

Par Patrick Pla

  "Le cerveau humain, avec ses 85 milliards de neurones chacun capable de former des centaines voire des milliers de synapses, apparait comme l’une des structures les plus complexes du système solaire. Si des cartographies à faible résolution existent, l’établissement du connectome, c’est-à-dire des connexions précises de chaque neurone individuel, représente un véritable défi. Avant d’espérer cartographier toutes les connexions ne serait-ce que d’une région précise (comme le cortex moteur par exemple), il s’agit de développer des outils sur des modèles plus simples. Le premier connectome avait été déterminé dès 1986 chez le nématode Caenorhabditis elegans une espèce qui présente 302 neurones associés par l’intermédiaire de 7000 synapses 1. En 2020, c’était au tour de la larve d’un Annélide Polychète, Platynereis dumerilii, de révéler la structure fine des connexions unissant ses 1500 neurones 2.

  Plus récemment, dans une prépublication du mois de novembre 2022, des chercheurs de l’université de Cambridge (Royaume-Uni) ont franchi un nouveau cap en cartographiant l’ensemble des connexions des 3013 neurones des ganglions cérébroïdes1 (« cerveau ») de la larve de drosophile (soit 544 000 synapses) 3. Pour ce faire, ils ont utilisé 4841 coupes fines de cerveau observables au microscope électronique et utilisé des programmes de reconstruction 3D.

  Ce connectome pourrait permettre de mieux comprendre des adaptations fonctionnelles « complexes » de la larve de drosophile, comme sa mémoire associative ou encore sa capacité à adapter son mode de locomotion à son environnement. L’intérêt de disposer du connectome de la drosophile est qu’il existe pour cette espèce modèle de nombreux outils permettant d’étudier le fonctionnement du cerveau, qu’il s’agisse d’outils génétiques (notamment optogénétiques qui permettent de dépolariser ou d’hyperpolariser des neurones bien précis) ou d’outils électrophysiologiques.

  La détermination du connectome des 135 000 neurones du cerveau de l’imago (adulte) nécessitera encore du travail. Cette reconstruction pourra cependant s’appuyer sur les résultats obtenus pour les ganglions de la larve, car certains circuits sont conservés. Néanmoins, au cours de la métamorphose, les modifications des connexions synaptiques sont importantes et la comparaison du connectome entre larves et adultes sera riche en enseignements. La reconstruction du connectome adulte pourra également se fonder sur les nombreuses observations en microscopie électronique de l’ensemble du cerveau adulte déjà disponibles.

  Comme avec le séquençage total des génomes, il ne faudra pas attendre de « miracles » des connectomes. En effet, ceux-ci ne donnent que peu d’informations sur les circuits les plus utilisés par rapport aux circuits activés plus rarement. Sans études fonctionnelles, il ne sera pas possible d’assigner une fonction précise à la majorité des connexions ni d’apprécier la « force » de celles-ci, qui est modulée par des mécanismes tels que la potentialisation à long terme ou la dépression à long terme. Par ailleurs, tout comme pour le séquençage complet du génome, les variations individuelles peuvent être importantes à cette échelle (du fait de la plasticité synaptique) et il faudra en tenir compte."

    The connectome of an insect brain | Science, 10.03.2023 https://www.science.org/doi/10.1126/science.add9330

  [Image] Le connectome de la larve de drosophile

A. Reconstitution 3D de l’ensemble des neurones du cerveau de la larve de drosophile. On voit notamment leurs prolongements vers la chaîne nerveuse ventrale. B. Cartographie des neurones sensoriels avec les afférences en provenance de la périphérie (entrée), les neurones qui traitent l’information directement (2e ordre) et les neurones que ces derniers contrôlent (3e ordre).

Auteur(s)/Autrice(s) : Winding et coll., 2022, traduit et adapté par Pascal Combemorel Licence : CC-BY Source : bioRxiv

  .

Crédits

Auteur(s)/Autrice(s)

Patrick Pla

Maître de conférences à l’université Paris-Saclay et enseignant à la préparation à l’agrégation et au Capes. Il est responsable d’Actuscienceprepa, un blog d’actualité scientifique.

Éditeur(s)/Éditrice(s)

Pascal Combemorel

Professeur agrégé de SVT. Il est le responsable éditorial du site Planet-Vie depuis septembre 2016.

Licence du texte de l'article

Creative Commons - Attribution - Pas d'utilisation commerciale

Bernadette Cassel's insight:

  Ce texte a été initialement publié à cette adresse le 5 février 2023 sur Actualités scientifiques Prépas, le blog d'actualités de Patrick Pla, maître de conférences à l'université Paris Saclay. La version proposée ici a été adaptée pour Planet-Vie.

Insects be like no brain here just mushroom! 

The mushroom bodies or corpora pedunculata are a pair of structures in the brain of insects, other arthropods, and some annelids (notably the ragworm Platynereis dumerilii).[2] They are also known to play a role in olfactory learning and memory. 

PdumBase – a transcriptome database and research tool for Platynereis dumerilii and early development of other metazoans

The marine polychaete annelid Platynereis dumerilii has recently emerged as a prominent organism for the study of development, #evolution, stem cells, regeneration, marine ecology, chronobiology and neurobiology within metazoans. Its phylogenetic position within the spiralian/ lophotrochozoan clade, the comparatively high conservation of ancestral features in the Platynereis genome, and experimental access to any stage within ... http://bit.ly/2nTyPsZ #RNAseq

Graduate position: Gottingen.AnnelidPhylogenomics

The Johann-Friedrich-Blumenbach Institute of Zoology and Anthropology at the Georg-August-Universitat Gottingen is looking to fill the position of a Doctoral/Ph.D. Student for research on Phylogenomics of Nereididae (Annelida) using a target enrichment strategy. The position is funded by the German Science Foundation (DFG) for a period of three years, with a salary according to the German salary scale TV-L E13 (65%), and should be filled by october 2018. The nereidid annelid Platynereis dumerilii is the best-known lophotrochozoan model system. Surprisingly, a detailed phylogenetic analysis of nereidids is lacking so far. The main objective of this project is to reconstruct a well-supported phylogeny for nereidids by using data from hybrid target enrichment with subsequent Illumina sequencing. Baits for target enrichment will be based on a set of transcriptomes from selected nereidid species generated within this project. This phylogenetic framework will be used to the current classification of nereidids and finally provide a stable placement of the model annelid Platynereis dumerilii. Based on this phylogeny, ancestral state reconstruction will be used to infer the evolution of reproductive modes, life-style and habitat preference of nereidid worms. Applicants need to hold a diploma or MSc degree in biology or a related field and to have solid experience with molecular methodology, particularly with respect to molecular systematics. Experience in generating and/or analysing next generations sequencing data is desirable. Knowledge about annelids or other lophotrochozoans would be helpful, but is not necessary. Working language is German and English. Doctoral students are supposed to take part in seminars and supervising students. This position is designed to foster young researchers and scientists and give the successful applicant the opportunity to pursue a doctoral degree. The University of Gottingen is an equal opportunities employer and places particular emphasis on fostering career opportunities for women. Qualified women are therefore strongly encouraged to apply in fields in which they are underrepresented. The university has committed itself to being a family-friendly institution and supports their employees in balancing work and family life. The mission of the University is to employ a greater number of severely disabled persons. Applications from severely disabled persons with equivalent qualifications will be given preference. With submission of your application, you accept the processing of your applicant data in terms of data-protection law. Further information on the legal basis and data usage is provided in the ‘Guideline General Data Protect Regulation (GDPR)' (German version only). Applications containing the common documents should be sent by July 1, 2018 in electronic form or by ordinary mail to Prof. Dr. Christoph Bleidorn, Johann-Friedrich-Blumenbach-Institut fur Zoologie und Anthropologie, Animal Evolution and Biodiversity, Georg-August-Universitat Gottingen, Untere Karspule 2, 37073 Gottingen, Germany, [email protected]. Please note: With submission of your application, you accept the processing of your applicant data in terms of data-protection law. Further information on the legal basis and data usage is provided in the Hinweisblatt zur Datenschutzgrundverordnung (DSGVO) via Gmail