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Tim Petzold

@timpetzold.bsky.social
864 followers 2.4K following 11 posts

Developmental Biologist | Postdoc in Holger Gerhardt's Lab at MDC in Berlin | Vasculogenesis | Angiogenesis | Hematopoiesis | Zebrafish | Former Embryo

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Reposted by Tim Petzold
Biology Open @biologyopen.bsky.social · 17/12/2025
#WntA is a crucial marker of stripe elements early in development for the Nymphalidae butterfly family. @jasminealqassar.bsky.social & co explore if WntA has maintained its role in stripe elements over 95 million years of evolution in the Hesperiidae family of butterflies. doi.org/10.1242/bio....
Hypotheses of stripe pattern homology between nymphalids and hesperiids. (A) Current summary of the nymphalid ground plan, mainly based on the terminology of Schwanwitsch (Nijhout, 1991; Schwanwitsch, 1924) and including recent updates by Otaki and Mazo-Vargas et al. (Mazo-Vargas et al., 2017; Otaki, 2012; Otaki, 2021; Schwanwitsch, 1956). Discalis elements (D1 and D2); CSS, central symmetry system (cyan); BoSS, border ocelli symmetry system (magenta); Oc, forewing border ocelli; pPf and dPf, proximal and distal parafocal elements; MBS, marginal band system (green). Colored vignettes denote vein intersection landmarks. Magenta square, junction between R and M vein trunks; yellow dot, M1-M2 junction; red star, junction between discal crossvein and M3; blue cross, M3-Cu2 junction; green triangle, Cu1-Cu2 junction. Rectangles feature the name of marker genes. (B) Ventral wing patterns of the nymphalid Prepona eugenes with ground plan annotations proposed by Schwanwitsch, 1956 (left: reproduction of published drawings; right: equivalent annotations as color overlays). (C) Phylogenetic relationship between Papilionoidae families. (D) Ventral wing patterns of the hesperiid P. sidae annotated as in panel A, and highlighting the inferred CSS predicted by Schwanwitsch, 1956 (left panel). According to this author, the CSS marks a grey pattern in forewings, and a dislocated white stripe pattern in hindwings, suggesting uncoupling of pattern and color state in fore/hindwings in skippers. The forewing CSS is markedly dislocated along the Cu1 vein (arrowhead).
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Daniel Ibrahim @danielibrahim.bsky.social · 16/10/2025
What is a promoter? And how does it work? We very happy to share our latest work trying to understand enhancer-promoter compatibility. I am very excited about the results of @blanka-majchrzycka.bsky.social, which changed the way I think about promoters www.biorxiv.org/content/10.1...
biorxiv.org
Enhancer-promoter compatibility is mediated by the promoter-proximal region
Gene promoters induce transcription in response to distal enhancers. How enhancers specifically activate their target promoter while bypassing other promoters remains unclear. Here, we find that the p...
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Reposted by Tim Petzold
Hannah Long @hannahlong.bsky.social · 10/11/2025
📣 Paper alert! I am delighted that our paper exploring the impact of Neanderthal-derived variants on the activity of a disease-associated craniofacial enhancer has been published in Development today! journals.biologists.com/dev/article/...
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Reposted by Tim Petzold
Biology Open @biologyopen.bsky.social · 16/10/2025
Blood stem and progenitor cells give rise to all blood cell types. Tim Petzold & co show that when Connexin 41.8 is present but impaired, it delays their initial formation and disrupts the timely activation of a key signalling pathway in #zebrafish embryos. doi.org/10.1242/bio....
cx41.8 is expressed in presumptive haemogenic endothelial cells of the dorsal aorta. (A) Design of the cx41.8:EGFP plasmid. The upper line indicates the cx41.8 locus structure. The lower line indicates the construct design. Purple boxes indicate the cx41.8 exons; blue boxes indicate the open reading frame; yellow boxes indicate the 4.5 kb sequence upstream of the cx41.8 start codon; black boxes indicate the transposon sequences and the green box indicates the EGFP coding sequence. (B) cx41.8:EGFP expression in the presumptive floor of the aorta at 24 and 28 hpf and in presumptive budding HSPCs (48 hpf). White arrowheads denote presumptive haemogenic endothelial cells in the floor of the aorta and budding HSPCs (48 hpf). (C) Flow cytometry analysis of double-positive cells in 48 hpf kdrl:mCherry+ or cx41.8:EGFP+; kdrl:mCherry+ embryos. (D) Expression of cx41.8:EGFP and kdrl:mCherry from 24-48 hpf. White arrowheads denote cx41.8:EGFP and kdrl:mCherry double-positive endothelial cells in the floor of the dorsal aorta. Scale bars: 100 μm (B and D).
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Reposted by Tim Petzold
Chase Bolt @chasebolt.bsky.social · 17/09/2025
Our work exploring a new explanation for the regulation of Hoxd genes and the #fin-to-limb transition. 🧪 It was an absolute joy working on this w/ @aurhin.bsky.social and @homeobox.bsky.social @denisduboule.bsky.social @neilshubin.bsky.social #evo-devo #InHoxWeTrust
nytimes.com
How Did Hands Evolve? The Answer Is Behind You.
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Reposted by Tim Petzold
Anders Sejr Hansen @andersshansen.bsky.social · 17/09/2025
Very interesting new @wbickmor.bsky.social commentary on the mechanistic mystery that is very distal enhancer-promoter interactions www.nature.com/articles/s41...
nature.com
Is enhancer-driven gene regulation all wrapped up? - Nature Reviews Genetics
In this Comment, Wendy Bickmore discusses mechanistic models of how 3D genome organization facilitates communication between distant enhancers and their target promoters to regulate gene expression.
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Reposted by Tim Petzold
Nature Portfolio @natureportfolio.nature.com · 07/09/2025
Living organisms are assumed to produce same-species offspring. A study in Nature reports a shift from this norm in Messor ibericus, an ant that lays individuals from two distinct species. go.nature.com/3V68MP0 🧪
This is figure 2, which shows M. ibericus queens lay males from two different species.
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Tim Petzold @timpetzold.bsky.social · 03/09/2025
Our humble gata2b in situ hybridization image made it onto the cover of @biologyopen.bsky.social! If you'd like to check out the story behind the image, the link to our new paper is: journals.biologists.com/bio/article/...
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Tim Petzold @timpetzold.bsky.social · 01/09/2025
Excited to share that the final version of our work on Connexin 41.8 in HSPC specification is out now in @biologyopen.bsky.social! If you're curious about how a connexin helps turn endothelial cells into blood stem cells, please have a read! journals.biologists.com/bio/article/...
journals.biologists.com
Connexin 41.8 governs timely haematopoietic stem and progenitor cell specification
Summary: Cx41.8 is necessary to launch the haemogenic program and induce HSPC formation at the correct time during zebrafish development via a ROS-Hif-Notch-Gata2b pathway.
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Reposted by Tim Petzold
Biomedical Picture of the Day BPoD @bpodaily.bsky.social · 18/08/2025
How the functional architecture of the zebrafish heart is shaped during development 📹 @tobyandrews.bsky.social et al @rashmi-priya.bsky.social lab @crick.ac.uk in @cellpress.bsky.social Developmental Cell ➡️ bpod.org.uk/archive/2025...
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Toby Andrews @tobyandrews.bsky.social · 06/08/2025
Thrilled to bits to see our latest work online in Dev Cell! 🥳 We wanted to know how cells build functional organs with precision🫀🫁📏 Here we show how coupling of cell shape and organ function fine tunes the form and contractile power of the developing #zebrafish heart 1/n tinyurl.com/cell-stretch
tinyurl.com
Mechanochemical coupling of cell shape and organ function optimizes heart size and contractile efficiency in zebrafish
Andrews et al. demonstrate that multiscale feedback between mechanical and chemical cues builds a functional heart to support zebrafish embryonic life. Cell recruitment and organ-scale forces drive tr...
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Jonathan Eisen @phylogenomics.bsky.social · 08/08/2025
Got this really cool, ghostly picture by accident the other day in Dillon Beach, CA. It is a Heermann's gull with both it's shadow and reflection. #birds
Juvenile Heermann's gull (very dark all over) in flight, flying over very very shallow water. Flying to the right maybe two feet off the ground. It's shadow is to the right. Just below the shadow is a reflection on the sheen of water.
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Development @dev-journal.bsky.social · 05/08/2025
Issue 14 is complete! On the cover: Drosophila eye imaginal discs stained for the pan-neuronal marker Elav (red or blue) and cell fate-specific markers to investigate basic cell-biological processes such as cell proliferation and morphogenesis during development. See: doi.org/10.1242/dev.204373
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Nick @gardenwizard.bsky.social · 30/07/2025
This is my first time seeing a Monarch on our property! I literally just purchased milkweed seeds and began preparing the area I’m going to plant in this fall. That’s quite the synchronicity. #gardening #bugsky #bloomscrolling #photography
A monarch butterfly on a pink zinnia
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Tim Petzold @timpetzold.bsky.social · 29/07/2025
Beautiful work using lineage-tracing, transplantation experiments and fate mapping to show that somites give rise to nephron progenitors www.nature.com/articles/s41...
nature.com
Somites are a source of nephron progenitors in zebrafish - Nature Communications
This study reveals that cells of the zebrafish kidney can originate from the somites, structures traditionally held as precursors to the skeletal muscle, challenging a century-old paradigm and prompti...
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Reposted by Tim Petzold
Society for Developmental Biology @socdevbio.bsky.social · 26/07/2025
🐌💫 Snail embryos never looked so fabulous! Tubulin (white), phospho-histone H3 (pink), and F-Actin (cyan) light up this early stage like a cytoskeletal disco ball. Image from Clemens Cabernard & Adam von Barnau Sythoff 🪩🧬 #FluorescenceFriday
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JLRay @jlray.bsky.social · 25/07/2025
Wow. Scientists have edited mosquito DNA to prevent the spread of malaria to humans "while supporting essential physiological functions... and negligible fitness costs" to the mosquito population. Potentially ending the mosquito-born spread of malaria to humans. www.nature.com/articles/s41...
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Anna A Monaco @annaamonaco.bsky.social · 23/06/2025
Mustering the courage to share my latest scicomm endeavour: I channelled my love for writing into a blog where I can hopefully bring the marvels of evolutionary biology and non-coding DNA to all Science lovers! darkgenomevo.wordpress.com/2025/06/22/i...
darkgenomevo.wordpress.com
It just takes one change
Here, I run though three examples of evolutionary novelty driven by single non-coding DNA changes: limb loss in snakes, gliding in sugar gliders, and coat coloration in African striped mice. These …
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Reposted by Tim Petzold
Axel Visel @axelvisel.bsky.social · 16/07/2025
No new genes needed to fly - just rewire what you have! 🦇🧬 Great new paper from the labs of @fany-real.bsky.social @stemundi.bsky.social @dariloops.bsky.social doi.org/10.1038/s415... #EvoDevo #SingleCell #BatWings
doi.org
Comparative single-cell analyses reveal evolutionary repurposing of a conserved gene programme in bat wing development - Nature Ecology & Evolution
Single-cell comparison of developing bat and mouse limbs reveals conservation of cell populations and gene expression patterns, and suggests repurposing of genes involved in proximal limb development ...
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Journal of Experimental Biology @jexpbiol.bsky.social · 26/06/2025
In her Perspective, Emilie Snell-Rood discusses the value of basic science, using the Morpho butterfly as an example of how this type of research has driven later innovation & highlights the value of government and institutional support for basic research journals.biologists.com/jeb/article/...
A photo of six butterflies which depicts the many different colours and patterns of butterflies in the genus Morpho. The top left is Morpho menelaus, the top middle is Morpho helenor, the top right is Morpho cypris. On the bottom left is Morpho rhetenor, the bottom middle is Morpho sulkowskyi, and the bottom right is Morpho hecuba. Photo credit: Emilie Snell-Rood.
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Dan 🐟 C @zebrafish007.bsky.social · 11/11/2024
The first 22 hours of #Zebrafish development. Blood vessels labeled in green #WeinsteinLab 🔬🧪
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Rory Cooper @rorylcooper.bsky.social · 04/06/2025
Excited to share our new research in @cp-iscience.bsky.social! We reveal that tortoise head scales are sculpted through two distinct developmental processes - chemical signalling and mechanical folding 🐢🔬🧪 @lanevol.bsky.social @genevunige.bsky.social www.cell.com/iscience/ful...
cell.com
Chemical and mechanical patterning of tortoise skin scales occur in different regions of the head
Biological sciences; Zoology; Evolutionary biology
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Antoine Zalc @antoinezalc.bsky.social · 04/06/2025
www.nature.com/articles/s41... Dev bio is amazing !!
nature.com
Maternal iron deficiency causes male-to-female sex reversal in mouse embryos - Nature
Iron-deficient conditions in pregnant mice can cause XY mouse embryos to develop female rather than male genitalia, revealing that iron metabolism has a role in determining male sex in mice.
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Arnau Sebé-Pedrós @arnausebe.bsky.social · 07/05/2025
Check out our latest work on the evolution of animal genome regulation out today in @nature.com. Nicely summarized below by @ianakim.bsky.social. www.nature.com/articles/s41... This is a major output from our ERC-StG project Evocellmap @erc.europa.eu at @crg.eu
nature.com
Chromatin loops are an ancestral hallmark of the animal regulatory genome - Nature
The physical organization of the genome in non-bilaterian animals and their closest unicellular relatives is characterized; comparative analysis shows chromatin looping is a conserved feature of ...
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Communications Biology @commsbio.nature.com · 15/05/2025
A review emphasizes the advantages of using zebrafish in research, outlines key differences in experimental approaches, and offers guidelines for designing studies in a way that enhances experimental rigor and reproducibility. www.nature.com/articles/s42...
nature.com
Zebrafishology, study design guidelines for rigorous and reproducible data using zebrafish - Communications Biology
A review emphasizes the advantages of using zebrafish in research, outlines key differences in experimental approaches, and offers guidelines for designing studies in a way that enhances experimental ...
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Shane Herbert @shaneherbert.bsky.social · 06/05/2025
My first post on Bluesky! Very excited to share our work just published in @science.org. We find that “Interphase cell morphology defines the mode, symmetry, and outcome of mitosis” - in angiogenesis and other tissues! www.science.org/doi/abs/10.1... www.science.org/doi/abs/10.1...
science.org
Interphase cell morphology defines the mode, symmetry, and outcome of mitosis
During tissue formation, dynamic cell shape changes drive morphogenesis while asymmetric divisions create cellular diversity. We found that the shifts in cell morphology that shape tissues could conco...
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Zebrafish Rock! @zebrafishrock.bsky.social · 24/04/2025
Look familiar? This beautiful video of #zebrafish embryogenesis was used for a 'one-frame per page' flipbook in the December 1996 edition of @dev-journal.bsky.social. Credit to Rolf Karlstrom and Don Kane. #ZebrafishFunFacts 🧪
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Arnaud Martin @evolvwing.bsky.social · 14/04/2025
Awesome new paper by @lucalivraghi.bsky.social et al. doi.org/10.1016/j.cu... in @currentbiology.bsky.social on the evo-devo of a butterfly color variation enjoy the show!
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Rory Cooper @rorylcooper.bsky.social · 09/04/2025
Thrilled that our image was selected for the cover of @royalsocietypublishing.org's Open Biology! We experimentally induced a developmental shift from normal footpad scales to mechanically-driven folding on chicken embryo digits 🐣🔬. Stay tuned—the full article is coming soon! 🧪 #DevBio
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The Guardian @theguardian.com · 02/04/2025
It's the moment you've all been waiting for... Invertebrate of the year voting is now open! 🗳️ Who will be your winner? theguardian.com/invertebrateoftheyear25
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Young Embryologist Network @yen-network.bsky.social · 31/03/2025
Send us your science images and art of embryos, organoids or stem cells! The YEN2025 Image Competition celebrates the beauty and complexity of developmental biology. Follow us to vote for the best entries between 2nd-16th May.
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bioRxiv Developmental Biology @biorxiv-devbio.bsky.social · 29/03/2025
Shoc2 Deficiency Disrupts Lymphangiogenesis through mTOR-Mediated Mitochondrial Dysfunction www.biorxiv.org/content/10.1101/202…
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Mathieu Preußner @mathpreu.bsky.social · 28/03/2025
In the mood for some gillspiration 🦓🐟 for #FluorescenceFriday ? Here, both endothelial reporters kdrl (yellow) and fli1a (white) highlight the four gill arches, showing several filaments and lamellae at 10 dpf. #microscopy #devbio #sciart
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Joyce Yu @joyceyu.bsky.social · 09/11/2024
Do you work in #DevBio and want to introduce the fascinating world of developmental biology to your family and friends? You can show them this science documentary, produced by the British Society for Developmental Biology, The Company of Biologists and Cambridge Filmworks! 📽️ youtu.be/avrmIs3vPUQ?...
youtu.be
BSDB - The Fascinating World of Developmental Biology (full length)
YouTube video by The Company of Biologists
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Chris Gug @gugunderwater.bsky.social · 23/03/2025
I am forever a huge fan of photographing “things living in drifting things” in the nighttime #plankton environment. Here we have a larval jack living inside a #jellyfish, for protection from its would-be predators
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Zebrafish Rock! @zebrafishrock.bsky.social · 23/03/2025
Multicolored ‘skinbow’ cells on an adult zebrafish scale. Credit to Dr. Chen-Hui Chen (prev. Duke University). #ZebrafishZunday 🧪
Layer of multi-colored cells on the surface of a zebrafish scale.
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Tim Petzold @timpetzold.bsky.social · 22/03/2025
Using a perpetual GAL4-UAS system for long-term lineage tracing! journals.biologists.com/dev/article/...
journals.biologists.com
Long-term labelling and tracing of endodermal cells using a perpetual cycling Gal4-UAS system
Summary: A continuous fluorescent labelling strategy for long-term cell tracing, enabling effective visualisation of endodermal cells and their development from embryos to adults.
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Tim Petzold @timpetzold.bsky.social · 20/03/2025
such beautiful images and exciting findings as always from @rorylcooper.bsky.social
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womensartbluesky.bsky.social @womensartbluesky.bsky.social · 20/03/2025
A recent photo of a starling murmuration as if smoke from a chimney has been called a "fluke" by its Yorkshire based, UK photographer, Anna Tosney #WomensArt
Photo of a landscape at dawn or dusk wuth hills a small building and a chimney in silhouette against a golden sky, above the chimney are a mass of birds flying in a large group resembling the shape of a tall whisp of smoke
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Stowers Institute @stowersinstitute.bsky.social · 17/03/2025
New collaboration paper from the Bazzini Lab published in @naturecomms.bsky.social explores enhanced RNA-targeting CRISPR-Cas technology in #zebrafish. Read more: go.nature.com/4krxgxL
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Katherine Brown @katherine-brown.bsky.social · 13/03/2025
Please do take a moment to read this joint editorial from @biologists.bsky.social's Editors-in-Chief. I'm feeling a bit lost in knowing how to support my friends and colleagues in the US right now. I wish there were more we could do than 'just' express our concern. If there is, please get in touch!
journals.biologists.com
Science under siege: protecting scientific progress in turbulent times
As Editors-in-Chief of The Company of Biologists' journals, we have been watching with growing concern the policy changes in the United States of America (USA) and the challenges that these are creati...
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John Wallingford @jbwallingford.bsky.social · 11/03/2025
A woman studies embryos for decades, struggles for funding and respect. She publishes under her husband’s name, until they divorce. A single mother, she moves across an ocean to continue her studies. It all sounds quite modern, until you learn that she also worried she’d be burned as a witch. 🧵 1/15
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Zebrafish Rock! @zebrafishrock.bsky.social · 09/03/2025
Four transgenic #zebrafish embryos with fluorescent blood vessels and blood cells. Credit to @pillaylab.bsky.social & @zebrafish007.bsky.social. #ZebrafishZunday 🧪
Four transgenic #zebrafish embryos with blood vessels in green, blood cells in red, and angiography in magenta. You can see the front half of each fish with the head, brain and eyes.
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the Node @the-node.bsky.social · 09/03/2025
Have you noticed the rotating header images on our site? They're winners of a competition we ran in 2021. Thank you @gaparicio.bsky.social @rorylcooper.bsky.social @zebrafish007.bsky.social @ebardot.bsky.social & Markus Schliffka for the images! Give us a visit: thenode.biologists.com
Collage of the five different header images, shown from top to bottom. 

Image descriptions:
1. Zebrafish lymphatics by Daniel Castranova. Lymphatic vessels shown in blue and neutrophils shown in orange in the head of a double transgenic juvenile zebrafish.
2. Catshark by Rory Cooper. Cleared and alizarin and stained hatchling catshark embryo.
3. Preimplantation mouse embryos by Markus Schliffka. Different stages of mouse preimplantation development from the zygote to the blastocyst, with nuclei in cyan and actin in grey.
4. Zebrafish retina by Gonzalo Aparicio. Retina from a 72hpf zebrafish embryo. Photoreceptor marker shown in red, while gfap:eGFP (a Muller cell marker) is shown z-depth pseudo-coloured.
5. Mouse embryo by Evan Bardot. Cleared E12.5 embryo labelled with antibodies against Cntn2 (green) and ColIV (magenta). Generated in Collaboration with James Muller.
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eLife @elife.bsky.social · 03/03/2025
Proteins that allow water to move in and out of cells help shape the development of new blood vessels. buff.ly/41n6ii0
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Li-Kun Phng @phnglab.bsky.social · 21/02/2025
Read the Research Highlight here! www.riken.jp/en/news_pubs... @RIKEN BDR
riken.jp
Water gives cells a push in blood vessel formation
RIKEN researchers have shown that that hydrostatic pressure is one of two mechanisms that control endothelial cell migration during angiogenic sprouting in zebrafish
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Li-Kun Phng @phnglab.bsky.social · 21/02/2025
Happy to announce that the final version of our paper on #endothelial cell #migration #mechanobiology, #angiogenesis, #hydrostaticpressure is out on @elife.bsky.social doi.org/10.7554/eLif... !! In our revised paper, we show that disrupted osmotic gradient and water inflow impair tip cell migration!
doi.org
Combined forces of hydrostatic pressure and actin polymerization drive endothelial tip cell migration and sprouting angiogenesis
Investigation of Aquaporin water channels unveils water inflow and build-up of hydrostatic pressure in endothelial tip cells as a novel mechanism of endothelial cell migration and blood vessel formati...
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John Wallingford @jbwallingford.bsky.social · 19/02/2025
The embryologist Ernst Haeckel is famous for his maxim that “ontogeny recapitulates phylogeny” and for sketchy imaging. While Haeckel figures prominently in #DevBiol, the Fifth Dalai Lama doesn’t. Perhaps he should, though. He scooped Haeckel by about 200 years. #LongBibliography 🧵 1/14
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Vengamanaidu Modepalli @venky-vnm.bsky.social · 17/02/2025
Woohoo! Our image made the cover! 🎉 @jexpbiol.bsky.social The image captures photosymbiotic Anemonia viridis pointing it's tentacles towards the light. journals.biologists.com/jeb
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Richard White @whitefishlab.bsky.social · 10/02/2025
For #zebrafish people - we have a joint @ZDMSociety @InfoIzfs webinar focused on single-cell tech coming up on February 20th. Featuring Yinan Wan, Jialin Liu and Loic Royer. Register here: www.izfs.org/education/we...
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