Category: 7. Science

The Dreams of Small Animals
ArtYard
June 21–October 5, 2025
Frenchtown, NJ

Can we learn to perceive as other beings do? Can we even learn to perceive other beings at all—not as objects of knowledge, but emissaries of worlds beyond our grasp? In The Dreams of Small Animals, Ash Eliza Williams probes metaphysical boundaries in paintings that channel the sensory perceptions of flowers, frogs, bugs, and birds. Williams uses multi-panel compositions that recall the sequential logic of a storyboard, but rather than translating the nonhuman into a legible narrative, they render their subjects more mystical in works where the boundaries between subject and environment become porous, vibrational.

The erotic The Dreams of a Dandelion (2024) is an eighty-three-panel sequence filled with ambiguous clefts, hairy mounds, and proboscises entering slits, realized in a citric orange that makes you salivate a little. The painting reminds you that a flower is a genital organ—its pollination a multispecies coitus—and effectively suggests an organism that does not perceive by seeing, but by touching. And yet, eyes make a distinctive appearance here, as exaggerated pictograms on the wings of descending butterflies. Many lepidopterans have developed striking eye-like spots, but a flower cannot “see” them—or can it? Perhaps it feels the touch of their gaze. Williams’s work does not approximate the physical sensorium of a dandelion as much as it speaks to perception itself as a super-sensory and spectral realm of encounter.

Have you ever stared at a bug and felt it looking back? Most arthropods have sophisticated sight, and the misconception that their compound eyes provide a “low-resolution” optical system says more about the limits of human perception, with its fixation upon the image. Our own eyes are essentially a stereoscopic camera, but an arthropod perceives space, light, and motion in ways we cannot fathom. Dragonflies are thought to process up to ten times more visual information, encompassing colors and wavelengths that are invisible to humans. Bees see ultraviolet light, and use it to read a hidden language of flowers.

Williams’s exhibition provokes unique speculations on how perception is limited by our body schema, anatomically engrained and culturally reinforced. Human cosmologies have often gravitated toward four-fold scales of space and time: four directions, four elements, four seasons. As animals with four limbs, quadruple poetics may feel most comfortable to us. How would we perceive the manifold poetry of a creature with fifteen pairs of legs, like a house centipede, whose very presence makes many humans uncomfortable?

Giant impact structures, including the potential remains of ancient “protoplanets,” may be lurking deep beneath the surface of Mars, new research hints. The mysterious lumps, which have been perfectly preserved within the Red Planet’s immobile innards for billions of years, may date back to the beginning of the solar system.

In a new study, published Aug. 28 in the journal Science, researchers analyzed “Marsquake” data collected by NASA’s InSight lander, which monitored tremors beneath the Martian surface from 2018 until 2022, when it met an untimely demise from dust blocking its solar panels. By looking at how these Marsquakes vibrated through the Red Planet’s unmoving mantle, the team discovered several never-before-seen blobs that were much denser than the surrounding material.

Animals

Gt(ROSA)26Sor^{tm14(CAGtdTomato)Hze} (Ai14, #007908), Cx3cr1^tm1Litt/J (#005582), Cx3cr1^{tm1.1(cre)Jung} (#025524), Gt(ROSA)26Sor^{tm32(CAG-COP4*H134R/EYFP)Hze} conditional allele (Ai32, #012569) and Csf1r^tm1.2Jwp (#021212) mice were obtained from the Jackson Laboratory. Hoxb8^IRES-Cre and Hoxb8^X-IRES-Cre mice were generated in our laboratory and reported by [11] and [9], respectively. Briefly, Hoxb8^X-IRES-Cre homozygous mutant mice contain an X-IRES-Cre allele at the Hoxb8 locus. The X-IRES-Cre allele was generated by replacing six amino acids in the homeobox DNA-binding domain with five alanines and glutamic acid. These mice exhibit the typical pathological grooming behavior originally reported [28]. Csf1r^∆FIRE mice were generated in our laboratory (details below), replicating the Csf1r^∆FIRE mouse line initially reported in [20].

Generation of Csf1r
^∆FIRE mutant mice

Csf1r^∆FIRE mutant mice were generated by pronuclear injection with gRNA1(20 ng/µl) and gRNA2 (20 ng/µl) and Cas9 protein (20 ng/µl) in C57BL6/J zygotes. gRNA1 sequence: 5′-GACTTGCGGGGTCAGCAAAC-3′ and gRNA1 sequence: 5′-AGCCCCCAATGAGTCTGTAC-3′. Founders were crossed to C57BL6/J, and their offspring were backcrossed to C57BL6/J mice for at least five times before initiation of experiments.

Flow cytometry cell sorting and analysis

Hematopoietic progenitor isolation and cell sorting

Embryo isolation and dissection were performed as previously described [5, 6]. Fetal livers were dissected from E12.5 embryos and placed on ice in 5% fetal bovine serum (FBS, Atlanta Biologicals) in 1X Hanks’ balanced salt solution (HBSS, Gibco). Fetal liver tissue was pooled according to their respective genotype (i.e., Hoxb8 WT: Cx3cr1^GFP/+; Hoxb8^IRES-Cre/+; Rosa26^{CAG-LSL-tdTomato/+} or Hoxb8^IRES-Cre/+; Rosa26^{CAG-LSL-tdTomato/+}, Hoxb8 conditional mutant: Hoxb8^{X-IRES-Cre/conditional}; Rosa26^{CAG-LSL-tdTomato/+}), then gently dissociated mechanically. Cells were passed through an 80 µm cell strainer to obtain a single-cell suspension.

Anti-mouse antibodies used consisted of the following: TER-119 PerCP-Cy5.5 (1:50, BioLegend, #116228) and c-Kit PE-Cy7 (1:100, Biolegend, #105814) in 5% FBS/1% BSA/1X HBSS. Cells were incubated with their respective antibody cocktail for 30 min on ice. Cells were counter-stained with 3 µM DAPI in 1X HBSS. WT and conditional mutant Hoxb8 hematopoietic progenitors were defined with the immunophenotype signature of DAPI^– Ter119^– kit^hi tdTomato⁺ GFP^+/- or DAPI^– Ter119^– kit^hi tdTomato⁺. Sorted WT and conditional mutant Hoxb8 hematopoietic progenitors were collected in sterile 1X HBSS media before transplantation. Flow cytometry data were obtained using the BD Bioscience FACS ARIA flow cytometry sorter. All FACS data were analyzed with FlowJo_v10.8.1 (Celeza GmbH).

Neonatal microglia cell isolation and cell sorting

Brains of neonatal mice were harvested and processed using the Brain Dissociation Kit for mouse and rat (#130-107-677, Miltenyi Biotec). Briefly, brains were dissected from P0–P4 mice and placed on ice in Dulbecco’s phosphate-buffered saline (DPBS, Gibco). Brains were from mice of the following genotypes (Hoxb8 WT: Hoxb8^IRES-Cre/+; Rosa26^{CAG-LSL-tdTomato/+} or Cx3cr1^GFP/+; Hoxb8^IRES-Cre/+; Rosa26^{CAG-LSL-tdTomato/+}). Neonatal brains were then enzymatically and mechanically dissociated using the gentleMACS^TM Octo Dissociator with Heaters (#130-096-427, Miltenyi Biotec) for 30 min at 37 °C. Cells were passed through a 70 µm cell strainer to obtain a single-cell suspension, followed by debris removal and red blood cell lysis steps. To minimize background signal and false positive signals in our cell sorting procedure, cells were resuspended in Fc block (1:2000, purified CD16/32, Biolegend, #101302) in 5% FBS/1X HBSS for 10 min, 4 °C before cell antibody staining.

Anti-mouse or anti-mouse/human antibodies used consisted of the following: CD45 APC (1:160, Biolegend, #103112) and CD11b Alexa Fluor^TM 700 (1:160, Biolegend, #101222) in 5% FBS/1% BSA/1X HBSS. Cells were incubated with their respective antibody cocktail for 30 min on ice. Cells were counter-stained with 3 µM DAPI in 1X HBSS. Hoxb8 microglia (DAPI^– CD45^lo CD11b^hi tdTomato⁺ or DAPI^– CD45^lo CD11b^hi tdTomato⁺ GFP⁺) and non-Hoxb8 microglia (DAPI^– CD45^lo CD11b^hi tdTomato^– or DAPI^– CD45^lo CD11b^hi tdTomato^– GFP⁺) were sorted from the WT Hoxb8 backgrounds. Sorted microglial cells were collected in sterile 1X HBSS media before transplantation. Flow cytometry data were obtained using the BD Bioscience FACS ARIA flow cytometry sorter. All FACS data were analyzed with FlowJo_v10.8.1 (Celeza GmbH).

Csf1r
^∆FIRE microglia isolation and flow cytometry analysis

Microglia isolation was performed as previously described [29]. Briefly, mice were euthanized by isoflurane and perfused with ice-cold 1X HBSS. Mouse brains were homogenized in a 15 mL Dounce homogenizer containing a digestion cocktail of 0.05% Collagenase D (Sigma), 0.1 µg/mL TLCK (Sigma), 0.025 U/mL DNase I (Sigma), and 0.5% Dispase (Roche), then digested at room temperature for 15 min. After centrifugation, cell pellets were resuspended in 5 mL of 30% Percoll/1X HBSS, overlaid with 5 mL 1X HBSS. The 70–30% interphase was collected and washed with 1X HBSS. The cell pellet was resuspended in 10% FBS/1X HBSS for flow cytometry analysis. Cells were stained with CD45 PE (1:100, Biolegend, #147711) and CD11b APC (1:100, Biolegend, #101212) in 1X HBSS on ice for 30 min. Cells were counter-stained with 3 µM DAPI in 1X HBSS. Flow cytometry data were obtained using the BD Bioscience FACSCanto II flow cytometry analyzer. All FACS data were analyzed with FlowJo_v10.8.1 (Celeza GmbH).

Intra-cerebral transplantations

Hematopoietic progenitors

freshly sorted WT or conditional mutant Hoxb8 hematopoietic progenitors (~2.5 × 10⁴ DAPI^– TER119^– kit^hi tdTomato⁺ cells/2–3 µL) or sterile 1X HBSS (sham controls) were transplanted bilaterally into the frontal hemispheres of P1–P4 Cx3cr1^Cre/+; Csf1r^fl/+ and Cx3cr1^Cre/+; Csf1r^fl/Δ recipient mice.

Neonatal microglia

freshly sorted WT Hoxb8 (~2.5 × 10⁴ DAPI^– CD45^lo CD11b^hi tdTomato⁺ or DAPI^– CD45^lo CD11b^hi tdTomato⁺ GFP⁺ cells/2–3 µL) and WT non-Hoxb8 microglia (~2.5 × 10⁴ DAPI^– CD45^lo CD11b^hi tdTomato^– or DAPI^– CD45^lo CD11b^hi tdTomato^– GFP⁺ cells/2–3 µL) or sterile 1X HBSS (sham controls) were transplanted bilaterally into the frontal hemispheres of P1–P4 Csf1r^∆FIRE/+ and Csf1r^{∆FIRE/∆FIRE} recipient mice. For co-transplantation, freshly sorted WT Hoxb8 (~2.5 × 10⁴ DAPI^– CD45^lo CD11b^hi tdTomato⁺ GFP⁺ cells/2–3 µL) and WT non-Hoxb8 microglia (~2.5 × 10⁴ DAPI^– CD45^lo CD11b^hi tdTomato^– GFP⁺ cells/2–3 µL) were mixed at the physiological equivalent of 70:30 WT non-Hoxb8:WT Hoxb8 microglia before bilateral transplantation into the frontal hemispheres of P1–P4 Csf1r^{∆FIRE/∆FIRE} recipient mice. As controls, blind injections of total microglia (~2.5 × 10⁴ DAPI^– CD45^lo CD11b^hi tdTomato^+/- GFP^+/- cells/2–3 µL), irrespective of lineage, were bilaterally transplanted in the same manner.

Cryosectioning and immunofluorescence

Postnatal brain tissue was processed and sectioned as previously described by [5]. For immunofluorescence, brain samples were briefly permeabilized with 0.2% Triton X-100, and 1% Sodium deoxycholate solution, then incubated overnight with a primary antibody mixture at 4 °C. The following day the sections were incubated with secondary antibodies for 2 h at room temperature. Sections were counter-stained with DAPI (D1306, Molecular Probes) and mounted with ProLong^TM Diamond Antifade Mountant (P36961, Invitrogen) and microscope cover glass (1419-10, Globe Scientific). Images were acquired on the Leica TCS SP5 confocal microscope and processed and analyzed using Imaris x64 8.0.2 (Bitplane), as described below.

Primary antibodies used: chicken anti-GFP (1:500, GFP-1020, Aves Labs), guinea pig anti-tdTomato-GP-Af430 (1:250, Frontier Institute, AB_2631185), anti-rabbit Iba1 (1:500, Wako, 019-19741), rabbit anti-mouse Tmem119 (1:500, 209064, Abcam), rat anti-P2RY12 (1:200, Biolegend, 848002), and rat anti-mouse CD206 Alexa Fluor 647 (1:200, Biolegend, 141712). Secondary antibodies used: goat anti-chicken Alexa Fluor 488 (1:500, A-11039, Thermo Fisher Scientific), goat anti-guinea pig Alexa Fluor^TM 555 (1:500, A-21428, Thermo Fisher Scientifc,), goat anti-rabbit Alexa Fluor^TM 647 (1:500, A-21245, Thermo Fisher Scientific), and goat anti-rat Alexa Fluor 647^TM (1:500, A-48265, Thermo Fisher Scientific). Both the primary and secondary antibodies that we have used have been tested for specificity and cross-reactivity.

Surgery implantation and housing

All survival surgeries were performed under aseptic conditions under stereotaxic equipment (Kopf instruments). Mice were anaesthetized using 4.0% isoflurane during induction and maintained at 1.5% throughout the surgical procedure. All surgically implanted mice were housed in individual cages till the end of the experiment. All stereotactic coordinates are in relation to bregma in mm. All mice received unilateral implantation of cannula (PlasticsOne, Roanoke, VA) for the brain region dorsomedial prefrontal cortex (dmPFC). Cannulas were implanted at the following stereotaxic coordinate: mPFC (+1.9 AP, 0.4 ML, −2.0 DV).

Optogenetic stimulation

For optical stimulation common to all behavioral experiments, multimode optical fiber (NA 0.37; 200 μm core; Thorlabs, Newton, NJ) was connected to a 473 nm light source through an FC/PC adapter. The free end of the fiber was connected to the implanted cannula before the initiation of the experiment. Following the experiment, the optic fiber was gently removed and a dust cap was secured on the cannula. The mice were kept back in the home cage to recover from the optogenetic stimulation.

Optogenetic induction of grooming behavior

All grooming behaviors in the experiments were measured by 6 min of video recordings with 2 min of each baseline, optogenetic stimulation and post stimulation condition within the home cage. The home cage environment was chosen for recording in order to ensure that other environmental factors do not affect the experimental outcome. Each experimental subject was pre-conditioned with optic fiber for 5 min before the experiment started. Laser power for the experimental and control subjects ranged between 2.8–7.6 mW for mPFC brain regions. The same laser powers were used to test control versus experimental subjects for the behavioral output. The laser power reported represents the power emerging from the laser light source. After each recording session, the optic fiber was carefully removed until the next experimental session. From the recorded videos, the behavioral phases of grooming were classified into phase III and phase IV if the experimental subject displayed facial grooming (phase III) or body grooming (phase IV). Each individual grooming bout corresponding to phase III and phase IV was scored for every experiment performed within the pre, during and post stimulation conditions for each experimental and control subject for every genotype tested. The latency or the onset of grooming was measured based on the first occurrence of phase III or phase IV grooming bout in response to optogenetic stimulation.

Confocal microscopy

Images were acquired on a Leica TCS SP5 confocal system. Brain sections were imaged for image acquisition with a 10X (0.4 NA, Leica) or 20X objective (0.4 NA, Leica) and 1.0X, 2.0X, or 5X digital zoom. Images were acquired at a 512 × 512 or 1024 × 1024 resolution and 200 or 400 Hz scan speed, using a 2.0 or 5.0 µm z-depth through the tissue.

Imaris image analysis

Images were processed using Imaris Image Analysis Software x64 (v8.0.2, Bitplane). The ‘Spots’ function counted the number of microglia per unit area (mm²). The diameter of the cell soma was set at 15 µm. To further identify the subsets of cells that co-label with Iba1, the spots were filtered using the ‘mean intensities’ of the fluorescence of the marker. The ‘Surface’ function was used to quantify the area of the analysis region.

Behavioral testing and analysis

All behavioral tests were performed between 6:30–10:00 pm, 30 min after the transition from light to dark phase, which begins at 6 pm. Mice were habituated to the behavioral room for 30 min under 0–5 Lux prior to testing acquisition. All tested mice were between 3–5-months-old.

Grooming test

The LABORAS behavioral assay (Metris B.V.) is a fully automated system that monitors specific mouse behaviors based on vibration (e.g., grooming, itching, locomotion, eating, drinking, and rest) and has been used in our laboratory [13]. Briefly, a single mouse is tested per cage and allowed to move freely while the software records the vibrations of their motions and assigns them to distinct behaviors. Illumination was at 0 Lux. To score behavioral phenotypes, mice underwent a two-hour trial once.

Light/dark box

The test apparatus consisted of a box (40 × 40 × 35 cm) divided into a dark, enclosed chamber and an open, brightly illuminated chamber. Illumination was at 600 Lux. To begin testing acquisition, a mouse was placed into the dark chamber (facing the transition opening) and allowed to move freely between the two chambers for 5 min. The total time spent in both chambers was analyzed. To score behavioral phenotypes, mice underwent a 5-min trial once. Animal movement was tracked using AnyMaze software.

Elevated plus maze

The apparatus consisted of four arms that were elevated ~50 cm from the ground: two enclosed by walls and the other with no walls. Illumination was at 100 Lux. Each mouse was acclimatized for 30 min in the testing room. To begin testing acquisition, each mouse was placed at the junction of the four arms with the mouse facing an open arm and allowed to move freely for 5 min as described by [30]. Duration in each arm was recorded by AnyMaze video-tracking software.

Statistical analysis

Data from all experiments were analyzed with GraphPad Prism software v10.0.1 (San Diego, CA). Unpaired t-tests were used for direct comparison between 2 data groups. Standard one-way and two-way ANOVA followed by post hoc analysis using Tukey’s multiple comparisons tests was used to compare multiple data groups. All data are graphically reported as mean ± sem. A P value < 0.05 was considered significant.

Ethics approval

All methods and experiments in this study have been performed on mice. Experimental procedures were approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Utah, Public Health Service Assurance #D16-00018 (A3031-01).

Scientists studying samples from the asteroid Bennu have found that it contains a remarkable mix of materials — some of which formed long before the sun even existed.

Taken together, the findings, described in a trio of recently published papers, show how Bennu has preserved clues about the earliest days of our solar system.

Arthropod appendages are specialized for diverse roles including feeding, walking, and mating. Fossils from the Cambrian period (539 to 487 million years ago) preserve exceptional details of extinct arthropod appendages that can illuminate their anatomy and ecology. However, fossils are typically limited by small sample sizes or incomplete preservation, and thus functional studies of the appendages usually rely on idealized reconstructions. In new research, paleontologists focused on Olenoides serratus, a particularly abundant trilobite species in the Cambrian Burgess Shale that is unique among trilobites owing to the availability of numerous specimens with soft tissue preservation that allow us to quantify its appendages’ functional morphology.

The Burgess Shale in British Columbia, Canada, is renowned for its exceptional preservation of soft tissues in fossils, including limbs and guts.

While trilobites are abundant in the fossil record thanks to their hard exoskeleton, their soft limbs are rarely preserved and poorly understood.

The trilobite species Olenoides serratus offers a unique opportunity to study these appendages.

Harvard University paleontologist Sarah Losso and her colleagues analyzed 156 limbs from 28 fossil specimens of Olenoides serratus to reconstruct the precise movement and function of these ancient arthropod appendages, shedding light on one of the planet’s earliest and most successful animals.

“Understanding behavior and movement of fossils is challenging, because you cannot observe this activity like in living animals,” Dr. Losso said.

“Instead, we had to rely on carefully examining the morphology in as many specimens as possible, as well as using modern analogues to understand how these ancient animals lived.”

The researchers also measured the range of motion of the legs in the living horseshoe crab species Limulus polyphemus.

“Arthropods have jointed legs composed of multiple segments that can reach upwards (extend) or downwards (flex),” they said.

“The range of motion depends on the difference between how far each joint can reach in either direction.”

“This range, along with the leg and shape of each segment, determines how the animal uses the limb for walking, grabbing, and burrowing.”

“Horseshoe crabs, common arthropods found along the eastern shore of North America, are frequently compared to trilobites even though they are not closely related.”

“Horseshoe crabs belong to a different branch of the arthropod tree, more closely related to spiders and scorpions, whereas trilobites’ family ties remain uncertain.”

“The comparison is due to the similarity in that both animals patrol the ocean floor on jointed legs.”

“The results, however, showed less similarity between the two animals.”

Unlike horseshoe crabs, whose limb joints alternate in their specialization for flexing and extending — a pattern that facilitates both feeding and protection — Olenoides serratus displayed a simpler, but highly functional limb design.

“We found that the limbs of Olenoides serratus had a smaller range of extension and only in the part of the limb farther from the body,” Dr. Losso said.

“Although their limbs were not used in exactly the same way as horseshoe crabs, Olenoides serratus could walk, burrow, bring food towards its mouth, and even raise its body above the seafloor.”

To bring their findings to life, the scientists created sophisticated 3D digital models based on hundreds of fossil images preserved at different angles.

Because fossilized trilobite limbs are usually squashed flat, reconstructing them in three-dimensions posed a challenge.

“We relied on exceptionally well-preserved specimens, comparing limb preservation across many angles and filling in missing details using related fossils,” said Harvard University’s Professor Javier Ortega-Hernández.

The team compared the shape of trace fossils with the movement of the limbs.

“Olenoides serratus could create trace fossils of different depths using different movements,” Dr. Losso explained.

“They could raise their body above the sediment in order to walk over obstacles or to move more efficiently in fast-flowing water.”

“Surprisingly, we discovered that the male species also had specialized appendages used for mating, and that each leg also had a gill used for breathing.”

The results were published on August 4, 2025 in the journal BMC Biology.

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S.R. Losso et al. 2025. Quantification of leg mobility in the Burgess Shale Olenoides serratus indicates functional differences between trilobite and xiphosuran appendages. BMC Biol 23, 238; doi: 10.1186/s12915-025-02335-3

As the Northern Hemisphere prepares for the autumnal equinox on September 22 and pumpkin-flavoured treats return in full force, the night sky is also offering a seasonal spectacle for skywatchers.

NASA says early risers on September 19 will be treated to a striking celestial trio just before sunrise. In the eastern sky, the Moon will appear closely aligned with Venus and Regulus, one of the brightest stars in the night sky. This rare conjunction offers a beautiful visual for both seasoned astronomers and casual skywatchers alike.

Later in the month, on September 21, Saturn will take center stage as Earth moves directly between Saturn and the Sun, During this time, Saturn will be at its closest and brightest point of the year. According to NASA, the planet’s iconic rings will be visible with just a small telescope, making this an ideal opportunity for backyard astronomers to get a clear view.

“Aside from the autumnal equinox in the Northern Hemisphere on Sept. 22 and the increase of pumpkin-flavored treats, September offers some celestial sights to enjoy. Just before sunrise on Sept. 19, you can catch a glimpse of a celestial trio. In the eastern skies, you will find the Moon cozied up to Venus and Regulus, one of the brightest stars in the sky,” NASA said.

It added, “A few days later on Sept. 21, Earth will position itself directly between Saturn and the Sun, meaning that Saturn will be at its closest and brightest all year. If you want to see its rings, all you will need is a small telescope.”

Here’s how you can watch Conjunction trio and Saturn at Opposition

According to NASA, the planet’s iconic rings will be visible with just a small telescope, making this an ideal opportunity for backyard astronomers to get a clear view.

“If you look to the east just before sunrise on September 19, you’ll see a trio of celestial objects in a magnificent conjunction. In the early pre-dawn hours, look east toward the waning, crescent Moon setting in the sky and you’ll notice something peculiar. The Moon will be nestled up right next to both Venus and Regulus, one of the brightest stars in the night sky,” NASA said.

It further mentioned, “The three are part of a conjunction, which simply means that they look close together in the sky (even if they’re actually far apart in space). To find this conjunction, just look to the Moon. And if you want some additional astronomical context, or want to specifically locate Regulus, this star lies within the constellation Leo, the lion.”

“Saturn will be putting on an out-of-this-world performance this month. Saturn will be visible with just your eyes in the night sky, but with a small telescope, you might be able to see its rings!” it added.

 

Researchers at University College London have discovered that activated amino acids and sulfur-containing compounds called thiols—both likely present on early Earth—can react in water at neutral pH to form high-energy thioesters. These thioesters transfer the activated amino acids to RNA in a process called RNA aminoacylation, preventing them from joining with free-floating amino acids. These findings suggest that thioesters may have provided the energy needed to unite nucleic acids and amino acids for protein biosynthesis—without the need for enzymes—in Earth’s earliest life-forms.

Proteins are essential to all life on Earth but, unlike nucleic acids such as DNA and RNA, cannot themselves pass specific sequences to their “offspring.”

“This is why life coordinates protein synthesis with another molecule, specifically RNA,” says Matthew W. Powner, lead author of the study (Nature 2025, DOI: 10.1038/s41586-025-09388-y).

In modern cells, enzymes called aminoacyl–transfer RNA (tRNA) synthetases attach amino acids to tRNA, activating them and programming the translation of RNA into proteins. But these enzymes themselves are products of the same genetic code—so how were they made in the first place? “Because you need these proteins to synthesize proteins, it’s a classic chicken-and-the-egg paradox,” Powner says. At life’s origin, these enzymes didn’t exist yet, so the team tried to figure out how amino acids attached to RNA spontaneously in water—the first way life would have had to connect genetic information to functional proteins.

Developing activated amino acids that react selectively with the 2′,3′-hydroxyl (–OH) groups of the ribose sugar of RNA—without enzymes and with other types of molecules that would be present in a cell or the early Earth at the origins of life—has proven challenging. Past attempts have led to hydrolysis or amino acids reacting with themselves. So the team considered the role that thioesters might play in this process.

Thioesters are high-energy compounds that are important in many of life’s biochemical processes and, like RNA aminoacylation, have ancient roots in biochemistry that predate the last universal common ancestor of all life on Earth. In the 1990s, Nobel laureate and biochemist Christian de Duve came up with the “thioester world” hypothesis, which posits that, based on their central role in metabolism, life’s first reactions must have been “powered” by thioesters.

After synthesizing and purifying nucleotides, nucleic acids, and activated amino acids, the team added thioesters to water at neutral pH at varying temperatures from ambient to freezing. They found that the thioesters were surprisingly stable in water, avoiding unwanted peptide formation between amino acids. In the presence of double-stranded RNA structures, thioesters selectively attached amino acids to the 2′,3′-diol groups of the ribose sugar at the 3′ of the double strand, even amid bulk water and excess amines.

The team then tested whether RNA could attach a variety of amino acids in water and found that aminoacylation occurred across all four RNA nucleotides on a broad range of amino acids, including charge residues such as arginine and lysine.

Finally the researchers investigated how these amino acids that were attached to RNA could be used for peptide synthesis under the same plausible prebiotic conditions. They found that when thioesters react with hydrogen sulfide, they form highly reactive thioacids. Those compounds could then be activated to bond with amino acids, even those attached to RNA—switching on peptide synthesis. Ultimately they found that thioesters were selective for aminoacylating RNA, while thioacids enable peptide bond formation, which allows for the stepwise, controlled synthesis of peptides attached to RNA.“A key step missing from prebiotic studies until now has been the use of chemical free energy transfer reactions to overcome the uphill chemistry of assembling polymers in water,” says Charlie Carter, a biochemist and biophysicist at the University of North Carolina School of Medicine who was not involved in this study. “The simplicity of the chemistry used here strongly suggests that it played a significant role in helping to create conditions for life to emerge,” he adds.

Astronomers have discovered an extraordinary celestial system containing a runaway pulsar fleeing the scene of a massive stellar supernova explosion. What makes this system even more spectacular is the fact that it should be “forbidden” in the empty region of the Milky Way in which it was found.

The system, given the name “Calvera” after the villain in the 1960 Western “The Magnificent Seven,” exists around 6,500 light-years above the densely populated plane of the Milky Way. In this region, stellar populations are sparse, and stars with the necessary mass needed to go supernova and to birth a neutron star at the heart of a pulsar should be vanishingly rare.

Robots can serve pizza, crawl over alien planets, swim like octopuses and jellyfish, cosplay as humans, and even perform surgery. But can they walk on water?

Rhagobot isn’t exactly the first thing that comes to mind at the mention of a robot. Inspired by Rhagovelia water striders, semiaquatic insects also known as ripple bugs, these tiny bots can glide across rushing streams because of the robotization of an evolutionary adaptation.

Rhagovelia (as opposed to other species of water striders) have fan-like appendages toward the ends of their middle legs that passively open and close depending on how the water beneath them is moving. This is why they appear to glide effortlessly across the water’s surface. Biologist Victor Ortega-Jimenez of the University of California, Berkeley, was intrigued by how such tiny insects can accelerate and pull off rapid turns and other maneuvers, almost as if they are flying across a liquid surface.

“Rhagovelia’s fan serves as an inspiring template for developing self-morphing artificial propellers, providing insights into their biological form and function,” he said in a study recently published in Science. “Such configurations are largely unexplored in semi-aquatic robots.”

Mighty morphin’

It took Ortega-Jimenez five years to figure out how the bugs get around. While Rhagovelia leg fans were thought to morph because they were powered by muscle, he found that the appendages automatically adjusted to the surface tension and elastic forces beneath them, passively opening and closing ten times faster than it takes to blink. They expand immediately when making contact with water and change shape depending on the flow.

By covering an extensive surface area for their size and maintaining their shape when the insects move their legs, Rhagovelia fans generate a tremendous amount of propulsion. They also do double duty. Despite being rigid enough to resist deformation when extended, the fans are still flexible enough to easily collapse, adhering to the claw above to keep from getting in the animal’s way when it’s out of water. It also helps that the insects have hydrophobic legs that repel water that could otherwise weigh them down.

Ortega-Jimenez and his research team observed the leg fans using a scanning electron microscope. If they were going to create a robot based on ripple bugs, they needed to know the exact structure they were going for. After experimenting with cylindrical fans, the researchers found that Rhagovellia fans are actually structures made of many flat barbs with barbules, something which was previously unknown.