It's the first transmissible cancer discovered in any fish.

A jellyfish can close a wound in real time, without stitches, scabs, or scars, a fascinating—and borderline miraculous—healing ability that has long perplexed scientists. 

Now, a new study in Molecular Biology of the Cell has finally revealed the secrets behind this process, identifying two cellular structures that act in a specific sequence.

Jocelyn Malamy, an associate professor at the University of Chicago, first observed this process a decade ago at the Marine Biological Laboratory. Using transparent, dime-sized jellyfish called Clytia hemisphaerica, she watched individual cells move toward each other to close a gap in the tissue.

Now, with colleagues Maxwell Sassaman and Manjula P. Mony, she has mapped the steps of this process and explored its broader significance.

A Flower That Never Stops Blooming

The free-swimming medusa most people picture when they hear “jellyfish” is only one phase of Clytia‘s life. It spends most of its life as a polyp colony attached to rocks, docks, or leaves, and it periodically produces medusae, much like a shrub produces flowers. While medusae live for only a few months, the polyp colonies can persist for much longer.

Clytia medusae are known for their ability to heal quickly. Small wounds close in minutes, and even larger injuries seal in under an hour, all without forming scar tissue. Malamy notes that this type of healing is similar to the scar-free repair seen in embryos.

Since Clytia are transparent, heal rapidly, and lack the immune-mediated inflammation that complicates wound healing in mammals, they serve as an excellent model organism. Scientists can watch epithelial cells close wounds in real time, without interference from scarring or immune reactions. The mechanisms uncovered in Clytia are likely relevant across many animals.

“A lot of the processes that we see in Clytia‘s wound healing are really similar to what you see in all other systems, including mammalian systems,” Malamy explains. “When you’re staring at these epithelial cells, you wouldn’t know this was a jellyfish.”

Two Structures, One Decision Tree

Epithelial cells form the surfaces of the body, including skin, the gut, and internal membranes, and must repair themselves after injury. Malamy previously described Clytia’s wound repair in 2017 and 2018. The new study addresses a longstanding question in epithelial wound healing: do wounds close by cells moving over the gap, or by an actin cable contracting to seal it? The findings show that both mechanisms operate in a specific sequence, with the basement membrane beneath the cells coordinating the transition between them.

The initial response involves lamellipodia, actin-rich extensions that move across the basement membrane, the protein layer beneath all epithelial tissues. These structures pull their parent cells forward to close the wound. Malamy’s team observed lamellipodia forming even in very small wounds within a single cell, a previously undocumented detail.

After the lamellipodia advance, an actomyosin cable forms and contracts after it covers the basement membrane. If damage or debris blocks the membrane, the cable closes the wound and removes debris that lamellipodia cannot cross.

For larger wounds, a third response occurs. When the gap is too wide for lamellipodia to bridge, regardless of how far the cells extend, the entire epithelial sheet lifts and migrates as a unit. Once lamellipodia from opposing edges meet, the same closing sequence resumes.

“This is a truly elegant mechanism where the system can rapidly adapt to heal all the kinds of wounds that might occur in nature,” Malamy says.

What’s Still Unrepaired

If epithelial repair mechanisms are conserved across animal evolution, as current evidence suggests, studies of jellyfish could reveal wound-healing processes that inflammation and scar formation obscure in mammals, making those processes difficult to observe directly.

Researchers have not yet fully understood the basement membrane, which coordinates these processes, and it remains the least understood aspect of wound repair. Scientists still do not know how organisms repair the basement membrane itself.

“It’s great that you can heal a wound by dragging the cells over it,” Malamy says, “but at some point, a damaged basement membrane has to get fixed.” That’s her next target.

Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.

Neil Mackenzie on the environmental impact of the Loch Kemp project

Your article (First major hydropower projects in Great Britain in 40 years given go-ahead, 26 June) describes the proposal to build three pumped storage schemes in the Scottish Highlands. But it does not mention the huge environmental cost.

One scheme, the Loch Kemp project, will draw water from Loch Ness and pump it into the upper reservoir created by enlarging Loch Kemp. A giant power station is to be built in protected ancient woodland on the shores of Loch Ness. This woodland is a special area of conservation, an internationally recognised site, and will be partly destroyed by the power station and access road.

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© Photograph: By Eve Livesey/Getty Images

© Photograph: By Eve Livesey/Getty Images

© Photograph: By Eve Livesey/Getty Images

Deep within the labyrinthine caves of northeastern Mexico dwells a remarkable species of fish, the blind Mexican cavefish (Astyanax mexicanus), whose evolutionary journey over hundreds of thousands of years has led it to adapt to a life shrouded in perpetual darkness. This fish has lost its eyes and pigmentation, hallmark traits of cave-dwelling organisms, while simultaneously acquiring a suite of physiological and behavioral adaptations tailored to survive in nutrient-scarce subterranean environments. Its dual existence as both a sighted surface fish and numerous independently evolved cave forms presents a unique biological system for examining how extreme environments drive evolutionary changes in brain structure, sensory processing, and behavior.

Researchers from Florida Atlantic University, collaborating with experts from institutions across the United States, have leveraged cutting-edge genetic and imaging technologies to decipher the neural underpinnings that distinguish cavefish from their surface relatives. By employing genetically engineered lines of this species that express fluorescent markers in their neurons, the scientists conducted real-time, whole-brain imaging at cellular resolution, unveiling intricate patterns of neural activity in response to sensory stimuli. This approach allowed direct comparison of neural circuitry when fish were exposed to alternating light and dark conditions, providing profound insights into how evolution recalibrates brain function to orchestrate behavior appropriate for radically different environments.

The study, recently published in Science Advances, reveals an astonishing reversal in sensorimotor behavior between the two ecotypes. Whereas surface fish exhibit increased locomotor activity upon sudden darkness—presumably an adaptive mechanism to enhance exploration for light sources—the cavefish respond inversely, with heightened activity triggered by light exposure. This counterintuitive response is theorized to serve as an adaptive avoidance strategy, steering cavefish away from illuminated cave entrances where predation risk and environmental fluctuations are higher. Such behavioral rewiring exemplifies how neural circuits can be evolutionarily repurposed rather than completely reinvented.

Central to this behavioral dichotomy is the alteration of activity within the posterior tuberculum, a brain region long implicated in sensorimotor integration and motivational states. The researchers identified not only region-specific shifts in activity patterns but also characterized a previously undescribed neuronal cell type that appears to play a pivotal role in mediating light-evoked responses. Intriguingly, neurons that in surface fish were activated by darkness exhibited robust activation in cavefish under light stimulus, underscoring the concept of evolutionary neural circuit reutilization. This finding challenges conventional assumptions that new behaviors necessitate de novo neural architectures and instead supports a model where existing circuits are modified to generate novel functional outputs.

Further mechanistic insights emerged from the investigation of dopaminergic signaling pathways. Dopamine, a neurotransmitter extensively involved in motor control, reward processing, and sensory modulation across vertebrates, was found to be centrally implicated in mediating these light-driven behavioral shifts. The study demonstrates that evolutionary tuning of dopamine circuits underlies the behavioral adaptation in cavefish, representing a conserved neurochemical axis modified through natural selection. This work sheds light on the plasticity and evolutionary potential of neuromodulatory systems in shaping species-specific behaviors.

These findings have significant implications beyond the realm of evolutionary biology. Since dopaminergic circuits are highly conserved from fish to mammals, understanding how these systems adapt to environmental pressures provides a window into fundamental brain functions relevant to health and disease. For example, alterations in dopamine signaling underlie numerous neurodevelopmental and neurodegenerative disorders in humans, including Parkinson’s disease, schizophrenia, autism spectrum disorders, and attention deficit hyperactivity disorder (ADHD). By elucidating natural mechanisms of dopamine circuit modification, this research may inform therapeutic strategies targeting related pathologies characterized by dysregulated sensory processing and motor responses.

The genetically controlled inheritance of photokinetic behavior further underscores the robustness of these adaptations. Crossbreeding experiments between surface fish and cavefish yielded hybrid offspring exhibiting a spectrum of activity responses to light and dark, confirming that these sensorimotor traits are encoded within the genome. Dissecting the genetic loci and developmental pathways responsible for remodeling neural circuits remains a crucial next step. Such investigations promise to unravel molecular drivers of behavioral evolution and highlight how genetic variation translates into neural and behavioral diversity.

The blind Mexican cavefish stands as an exemplary model system to probe how sensory systems are sculpted by evolutionary forces and how brains dynamically reconfigure to interpret environmental signals. By disentangling the neural rewiring that facilitates survival in total darkness, researchers gain a clearer picture of how sensory inputs are transformed into adaptive motor outputs. This contributes to a broader understanding of brain evolution applicable across vertebrates and illustrates nature’s ingenuity in leveraging existing neural frameworks to solve complex ecological challenges.

Through advanced imaging and behavioral quantification, the Florida Atlantic University team has carved new ground in charting the neural circuit modifications that underpin a dramatic shift from dark-evoked to light-evoked photokinesis. This work provides a compelling paradigm illustrating that evolution does not invariably mandate the invention of novel structures but can preferentially repurpose and recalibrate pre-existing neural substrates to generate behavioral novelty.

The evolutionary narrative of the blind Mexican cavefish enriches our comprehension of neuroecology—the study of how nervous systems evolve in response to environmental variables. It reveals that sensory deprivation, far from being a mere loss, can instigate intricate neural and behavioral innovations that confer selective advantages. Such insights deepen our appreciation for the complexity and flexibility inherent in neural systems when confronted with extreme ecological niches.

Finally, this research exemplifies the power of integrative methodologies combining genetics, neurobiology, and behavioral science to unravel the enigma of brain evolution. It paves the way for future interdisciplinary studies to identify specific genes orchestrating neural circuit plasticity, decode developmental mechanisms driving neuronal subtype specification, and ultimately connect genotype to phenotype in a context of evolutionary adaptation.

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Subject of Research: Animals

Article Title: Evolution of a central dopamine circuit underlies adaptation of a light-evoked sensorimotor response in the blind cavefish

News Publication Date: 22-May-2026

Web References:
DOI: 10.1126/sciadv.adv3770

Image Credits: Florida Atlantic University

Keywords: Evolutionary biology, Brain, Neurons, Sensory neurons, Photoreceptors, Neurological disorders, Neurodegenerative diseases, Parkinson’s disease, Schizophrenia, Fish, Brain activity maps, Behavioral ecology, Ecological adaptation, Neural pathways, Dopamine pathways

In a groundbreaking study shedding light on the molecular intricacies of arousal regulation, researchers from Pompeu Fabra University (UPF) and the Centre for Genomic Regulation (CRG) have unveiled the profound influence of neuronal microexons on behavioral states in zebrafish. This study elucidates how subtle alterations in these tiny genetic fragments can trigger hyperarousal—a state marked by heightened neural excitability and pronounced insomnia-like symptoms—which echoes the pathophysiological features observed in various neurodevelopmental disorders. The implications extend far beyond aquatic models, offering a window into the conserved mechanisms of arousal that potentially inform conditions such as autism spectrum disorder and schizophrenia in humans.

Arousal represents a fundamental neurophysiological process essential for survival, enabling organisms to respond to external and internal stimuli with appropriate behavioral and neural adaptations. This highly conserved mechanism across species ensures a meticulously balanced state, modulating responsiveness between lethargy and sensory hypersensitivity. Dysregulation of this balance manifests clinically as either diminished responsiveness or excessive wakefulness and sensory overload, typical hallmarks of stress and various neurodevelopmental pathologies.

Fundamental to this regulatory system is the diversity of proteins synthesized during development and adulthood through alternative splicing—a sophisticated post-transcriptional gene editing process. Alternative splicing enables the generation of multiple functionally distinct protein isoforms from a single gene, often mediated by the inclusion or exclusion of microexons. Microexons are exceptionally short exonic sequences within neuronal genes that profoundly influence protein function and neuronal circuit dynamics despite their minuscule size.

The investigative team employed zebrafish larvae, leveraging their optical transparency and genetic tractability to scrutinize the behavioral consequences of neural microexon misregulation. Larvae exhibiting abnormal microexon patterns demonstrated conspicuous hyperarousal behaviors including disrupted swim patterns and shortened sleep duration. “These larvae not only sleep less frequently but also take considerably longer to initiate sleep,” remarks first author Tahnee Mackensen. This behavioral hyperactivity parallels neural hyperexcitability, suggesting microexon regulation as a pivotal determinant of neurobehavioral states.

At the cellular signaling level, the researchers identified dysregulated cyclic adenosine monophosphate (cAMP) cascades as a key mediator of the observed hyperactive state. cAMP is a ubiquitous second messenger involved in modulating neuronal excitability and synaptic plasticity. The altered splicing of microexons modulates cAMP synthesis and degradation pathways, leading to an aberrant excitation of forebrain neurons in hyperaroused larvae. Notably, this altered cAMP signaling manifests as heightened cAMP-dependent protein kinase A (PKA) activity and subsequent phosphorylation of the transcription factor CREB, implicating the canonical cAMP-PKA-CREB pathway in the regulation of arousal.

The study’s pharmacological interventions underscore the centrality of cAMP regulation in arousal control. Application of cAMP inhibitors normalized the elevated neural activity and behavioral hyperarousal in mutant fish, whereas artificially elevating cAMP in wild-type fish recapitulated the hyperactive phenotype. This bidirectional modulation fortifies the concept that neuronal cAMP levels function as a ‘thermostat’ for arousal states, fine-tuning neuronal excitability and behavioral responsiveness.

Beyond the immediate findings in zebrafish, this research builds upon prior observations in drosophila models demonstrating that microexon disruption similarly impairs sleep and elevates arousal. “The parallel between species indicates an evolutionarily conserved arousal mechanism,” explains Manuel Irimia, senior author. This conservation implies that microexon misregulation, while mechanistically nuanced, may contribute to the neuropsychiatric symptomatology observed in mammals, including humans.

Human neurological disorders such as autism and schizophrenia are often accompanied by sleep disruption and sensory processing anomalies attributed, in part, to aberrant microexon splicing. While microexon alterations are unlikely to be sole causative factors, they may exacerbate or modulate disease phenotypes by disturbing neural excitability homeostasis. These insights prompt a reevaluation of therapeutic strategies aimed at restoring microexon splicing fidelity or modulating cAMP signaling pathways to alleviate neurodevelopmental symptomatology.

Moreover, the link between this microexon-cAMP pathway and mood disorders such as anxiety and depression opens compelling avenues for future research. The cAMP-PKA-CREB axis has well-documented roles in synaptic plasticity and mood regulation, suggesting that microexon-associated dysregulation could contribute to broader neuropsychiatric conditions. “This discovery might just scratch the surface of a complex regulatory network influencing brain function,” notes Mackensen.

The transparency and genetic accessibility of the zebrafish model provided unparalleled opportunities to visualize and quantify internal states through behavioral readouts. Advanced imaging of larval swimming patterns and direct measurement of neurochemical parameters furnished robust correlative evidence linking genetic alterations to functional outcomes. These technical advancements highlight the integrative power of model organisms in neuroscience.

Importantly, this research received support from an array of prestigious funding bodies, including the Horizon 2020 Framework Programme, the Marie Sklodowska-Curie Actions, and the Wellcome Trust, emphasizing the global significance and collaborative nature of this work. The study’s publication in Science Advances confirms its high impact and relevance to the scientific community.

As the team pursues translational studies, the prospect of correcting arousal imbalances by manipulating cAMP pathways or restoring microexon expression presents a promising frontier. This is especially critical given that aberrant arousal and sleep disturbances profoundly impair quality of life in neurodevelopmental disorders. The findings pave the way for multidisciplinary approaches integrating molecular genetics, neurobiology, and pharmacology to develop targeted interventions.

In summation, the identification of neuronal microexons as key modulators of arousal states via the cAMP-PKA-CREB pathway in zebrafish represents a seminal advance in our understanding of the molecular substrates governing complex behavioral phenotypes. This research not only deciphers fundamental biological mechanisms but also holds translational potential to inform therapeutic avenues for neuropsychiatric conditions marked by disrupted arousal and sleep.

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Subject of Research: Animals

Article Title: Neuronal microexons modulate arousal via the cAMP-PKA-CREB pathway in zebrafish

News Publication Date: 19-Jun-2026

Web References: 10.1126/sciadv.ady8291

Image Credits: UPF – CRG

Keywords: Exons, Gene splicing, Developmental neuroscience, Anxiety, Sleep disorders, cAMP signaling, Zebrafish

In a groundbreaking discovery that broadens our understanding of marine life communication, researchers at Oregon State University have identified a novel chemical signaling mechanism among bat rays (Myliobatis californica) that warns conspecifics of looming threats. This chemical disturbance cue, previously documented only in bony fish, now emerges as a key anti-predator strategy in cartilaginous fishes—specifically rays—revealing a layer of behavioral complexity that challenges long-held assumptions about elasmobranch social interactions.

Dr. Joshua Bowman, leading the study from OSU’s Big Fish Lab, devised an elegant experimental setup employing three isolated tanks interconnected through water flow but segregated visually and acoustically to eliminate confounding sensory influences. Each tank housed an individual bat ray, with one designated as the “signaler” and the other two as “receivers.” By simulating predatory pressure through a gentle chase of the signaler ray, the experimenters induced a natural defensive response while ensuring no physical harm.

Strikingly, within mere seconds of the signaler tank’s water being directed towards the receiver tanks, the bat rays in these isolated environments exhibited marked behavioral shifts characterized by increased swimming speed and evasive maneuvers. These responses mimic a flight reaction, confirming the transfer of a chemical alarm cue through the aquatic medium—a sensory pathway previously undocumented in cartilaginous species.

This discovery bears profound implications for understanding elasmobranch ecology and survival strategies. Bat rays, along with sharks and skates, belong to a class of cartilaginous fishes characterized by their distinct evolutionary lineage and physiology. These findings suggest sophisticated intraspecies chemical communication channels functioning as early-warning systems against predation risks, potentially reshaping our perception of their behavioral ecology.

Moreover, the research carries significance beyond bat rays. Whites sharks, apex predators renowned for their fearsome reputation, are known to exhibit avoidance behaviors when orcas, their potential predators, are nearby. Yet, these sharks often do not have direct visual contact with orcas. This study’s insights into chemical alarm signaling hint at unseen communication mechanisms that might underlie such evasive behavior, opening new avenues for exploration into shark sensory biology and their interactions within the marine predator-prey network.

The experiment’s methodological rigor enhances the credibility of these findings. By isolating variables—eliminating acoustic and visual cues—the team conclusively linked behavioral changes to chemical signals. High-resolution overhead video recordings captured nuanced shifts in locomotion dynamics, quantitatively analyzing the rays’ rapid swimming velocity increases immediately following exposure to the alarm chemicals. These data underscore a robust flight response triggered solely by chemical disturbance cues.

While the precise chemical compound or combination responsible for the alarm signaling remains unidentified, the study establishes a foundation for future biochemical and molecular investigations. Identifying the molecular structure of the alarm cue could unlock transformative understandings of elasmobranch chemical ecology, potentially informing conservation strategies and offering biomarkers for monitoring stress responses in marine populations.

Importantly, the research foregrounds broader ecological and ethical considerations. The evolutionary origin of these chemical disturbance cues underscores their critical role in survival and natural behavior modulation. Human interactions—whether through scientific research, fisheries, or recreational activities—may inadvertently trigger stress dissemination across populations via such chemical signals, amplifying disturbance impacts beyond the initially affected individual.

The OSU Big Fish Lab, recognized as a leading shark research facility on the U.S. West Coast, continues to spearhead innovative studies uncovering the intricate lives of marine cartilaginous fishes. This collaboration, involving co-authors Jamie Cornelius and Mauricio Cantor, integrates expertise spanning marine ecology, physiology, and animal behavior, thereby enhancing multidisciplinary perspectives crucial to advancing marine science frontiers.

By employing bat rays as a proxy for studying elusive white shark behavior, the researchers circumvent logistical challenges inherent to large predator studies. Bat rays’ accessibility and manageable size provide an ethical and practical model to dissect communication modalities applicable across related species, ensuring experimental feasibility while preserving ecological validity.

This study, recently published in the Journal of Experimental Zoology Part A: Ecological and Integrative Physiology, represents a significant milestone in marine biology. It not only documents, for the first time, chemically mediated disturbance cues in cartilaginous fishes but also stimulates critical reflection on the sensory worlds of sharks and rays, organisms whose behavioral sophistication may be far richer than previously appreciated.

Collectively, these findings herald a paradigm shift in our understanding of underwater communication networks. They remind us that aquatic ecosystems host complex, often hidden, language systems integral to species survival. As we deepen our inquiry into these chemical dialogues, we unlock new insights essential for protecting marine biodiversity in a rapidly changing ocean environment.

Subject of Research: Animals
Article Title: Behavioral Evidence for a Chemical Disturbance Cue in Bat Rays (Myliobatis californica)
News Publication Date: 10-Jun-2026
Web References: http://dx.doi.org/10.1002/jez.70102
References: Journal of Experimental Zoology Part A: Ecological and Integrative Physiology
Keywords: chemical disturbance cue, bat rays, cartilaginous fish, elasmobranchs, shark behavior, marine communication, anti-predator strategy, predator-prey interactions, aquatic chemical signaling, flight response, marine ecology, behavioral study

Marine biologists have identified a new species of the shark genus Hemiscyllium in the waters of eastern Papua New Guinea, expanding a remarkable group of reef-dwelling sharks known for using their four fins to ‘walk’ across the seafloor.

The post New Species of Walking Shark Discovered off Papua New Guinea appeared first on Sci.News: Breaking Science News.

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The post Google quer reduzir dependência da TSMC e negoceia a produção de um novo chip de IA com a Samsung e Intel appeared first on Tek Notícias.

Paleontologists have described an assemblage of marine fish fossils from the 62.2-million-year-old site of Qreiya 3 in the Eastern Desert of Egypt, providing a window into this transition.

The post Fish Fossils from Early Paleocene Fill 10-Million-Year Gap after Dinosaur Extinction appeared first on Sci.News: Breaking Science News.

Scientists have uncovered evidence that tiny microbes living inside fish may be helping shape the chemistry of the world’s oceans. The new study, led by former graduate student Anthony Bonacolta at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, suggests that bacteria in fish intestines may work together with their hosts [...]

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Paleontologists in Argentina have identified a previously unknown species of unenlagiid dinosaur that stalked freshwater wetlands during the Late Cretaceous epoch, adding to evidence that some dinosaurs specialized in catching fish.

The post New Dinosaur Species from Argentina May Have Specialized in Catching Fish appeared first on Sci.News: Breaking Science News.

A marine biologist studying the photophores of a bioluminescent fish species found needle-shaped guanine crystals that scatter and redirect light instead of merely reflecting it, a discovery that could inspire more efficient biomedical and optical devices.

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