1 May 2026

Today’s Visualized tumbles about with a bio-inspired bot. But first, catch up on the latest science news, including why penguins waddle and high-performing emergency room AIs.

MIcrobiology | Science

Bacterium gets by with one of its amino acids partially removed

Of the hundreds of types of amino acids found on Earth, it’s a mystery why life settled on 20 as the building blocks for all its proteins. Although certain species can use more—some microbes employ up to 22—no one’s ever found one using fewer. But now scientists are closer to creating such an organism, after partially eliminating one of the 20 amino acids from the bacterium Escherichia coli.

In the study, published this week in Science, researchers attempted to swap the amino acid isoleucine with the similarly structured valine in each of 50 protein subunits that make up E. coli’s ribosomes—the protein factories of the cell. For more than one-third of the modified proteins, that approach worked, and the resulting bacterial strains grew normally. AI tools then offered ways to compensate for swaps in the other subunits, for example by switching out amino acids neighboring the replaced isoleucine. With further tweaks and some trial and error, the team eventually managed to combine 21 of the rewritten ribosomal proteins in one bacterium, which still grew, albeit relatively slowly.

The findings might suggest new ways to synthesize proteins with bespoke functions in medicine and biotechnology. And they offer a glimpse into how earlier, simpler life forms might have lived with fewer than 20 amino acids said Christopher Snow, a protein engineer who was not involved in the work. The results “lend support to the idea that [early] life was probably just fine for a while with a smaller palette.”

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Animals | News from Science

Why do penguins waddle? Mysterious muscle may be key

Macaroni penguins waddling their way around. LIam Quinn via WIKIMEDIA COMMONS | CC BY-SA

One of the most charming features of penguins is also one of the most mysterious. Why do the birds waddle like sumo wrestlers on a bender? Scientists have long blamed their unusual skeleton: Penguin knees, which are tucked into their body cavity, are bent and arranged in a perpetual squat. But that’s not the whole story.

Enter the cadavers of two macaroni penguins whose bodies were donated to science. When researchers compared the musculature of the animals with that of non-waddling birds, they noticed something unusual about a muscle called the m. flexor cruris medialis, which attaches to the tibiotarsus, a long leg bone in birds. Researchers knew this muscle helped birds bend their knees, but they’d never precisely clarified the nearby muscles and bones it connects to in penguins.

The dissections revealed a mysterious part of the m. flexor cruris medialis that attaches to a different section of the tibiotarsus than previously thought, suggesting a hitherto unknown function. This tissue is actually entirely separate from the m. flexor cruris medialis, the team reported last month in The Anatomical Record, and serves to connect a penguin’s two knees. Considered in itself to be a muscle, it has not been reported in any other birds, making it unique to penguins. The researchers have christened it m. adductor tibialis for its ability to bind, or adduct, the legs inward.

This muscle provides the birds an ability to more easily maneuver their cramped leg posture, said co-author Justin Georgi. “It stabilizes the leg against the body when the penguin is leaning to one side,” he added, and provides extra energy to allow the animal to swing its other leg forward as it balances on the stabilized leg, completing the waddle.

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Medicine | Science

Paging Dr. LLM

If you walk into an emergency room in 10 years, you could encounter a new type of caregiver: an AI system designed to get you diagnosed faster and help your care team make more informed decisions. While you sit in the waiting room, you’d be hooked up to a blood pressure cuff that’s constantly and autonomously monitored. All the while, an AI agent will be listening in while you and your doctor talk about your symptoms, ready to flag any mistakes your physician makes or suggest next steps.

This vision of AI-assisted emergency healthcare may soon be reality. In a new Science study, researchers show that a large language model (LLM) often outperformed physicians at diagnosing complex and potentially life-threatening conditions, including decreased blood flow to the heart, even in the fast-moving stages of real emergency room care when information is limited. In early emergency room cases, the model identified the correct or a very close diagnosis in about 67% of cases, compared with roughly 50% to 55% for physicians.

“Evaluating AI in medicine demands both depth and breadth across different clinical tasks and settings,” and these authors were able to incorporate both in this study, said computer scientist Shreya Johri. Still, she noted, wide adoption of these AI systems in healthcare will hinge on knowing the contexts in which they’re most reliable.

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Visualized

Twirlbot doing its best tumbleweed impression. Chen et al./Science Advances (2026)

In the new hit sci-fi movie Project Hail Mary, the lovable alien Rocky curls up into a chunky ball to roll around the spacecraft. His form of locomotion is pretty effective: Rolling spheres don’t have any turning radii, making them easily maneuverable in infinite directions. And if made of a soft material, spheres can traverse over landscapes including sand, snow, and vegetation.

Because of such advantages, researchers set out to design a rolling, spherical bot that doesn’t have cumbersome motors, processors, or other power systems. They took inspiration not from sci-fi movies, but old westerns: tumbleweeds. The team wove together six loops of elastic material that activated under light to create a robot named “Twirlbot.” Since tumbleweeds expose all their sides to the Sun as they roll, the bot was constantly exposed to light, which caused the material to contract and expand in ways that pushed it forward. Twirlbot could move in all directions of its own accord, and withstood wind resistance and challenging terrains including gravel, sand, leaves, and soil.

Researchers envision using Twirlbots for dispersing seeds, much like real tumbleweeds. In tests, the robots were even capable of carrying loads heavier than they were. Such research has “opened the way for the next generation of untethered, autonomous, energy-sustainable, and cost-effective robots, particularly in the fields of robotics and agriculture,” write the authors.

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podcast

Watching a spiders’ heart beat, epigenetic ethics, and what science biographies reveal about fame

By Sarah Crespi, David Grimm, Adrian Cho, Valerie Thompson, Angela Saini | 30 April 2025

On this week’s show: A roundup of online news stories, ethical considerations as we learn more about inheritance without DNA, and a new book series on the lives of scientists.

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Et Cetera

A spikey pattern

Brief electrical bursts called interictal epileptiform discharges, or interictal spikes, can occur hundreds or thousands of times a day in people with epilepsy. Though not as dangerous as seizures, they can cause temporary confusion and contribute to long-term cognitive problems, even in those whose seizures are controlled. Now, highly detailed recordings from human brains reveal these spikes occur in a choreographed sequence of events that is consistent and predictable.

Nature Neuroscience Paper | Read more at News from Science

To infinity, not beyond

To many mathematicians, the idea of a universe without infinity is heresy. “When you first pitch the idea of ultrafinitism to somebody, it sounds like quackery—like ‘I think there’s a largest number’ or something,” one such ‘heretic’ explained. However: “If there might only be finitely many things, then we’d better also be using a math that doesn’t just assume that there are infinitely many things at the get-go.”