Biology – Page 2

Small charges in water spray can trigger the formation of key biochemicals

biochemistry, Biology, chemistry, origin of life, Physics, Science / Mike M. / March 15, 2025

Once his team nailed how droplets become electrically charged and how the micro-lightning phenomenon works, they recreated the Miller-Urey experiment. Only without the spark plugs.

Ingredients of life

After micro-lightnings started jumping between droplets in a mixture of gases similar to that used by Miller and Urey, the team examined their chemical composition with a mass spectrometer. They confirmed glycine, uracil, urea, cyanoethylene, and lots of other chemical compounds were made. “Micro-lightnings made all organic molecules observed previously in the Miller-Urey experiment without any external voltage applied,” Zare claims.

But does it really bring us any closer to explaining the beginnings of life? After all, Miller and Urey already demonstrated those molecules could be produced by electrical discharges in a primordial Earth’s atmosphere—does it matter all that much where those discharges came from? Zare argues that it does.

“Lightning is intermittent, so it would be hard for these molecules to concentrate. But if you look at waves crashing into rocks, you can think the spray would easily go into the crevices in these rocks,” Zare suggests. He suggests that the water in these crevices would evaporate, new spray would enter and evaporate again and again. The cyclic drying would allow the chemical precursors to build into more complex molecules. “When you go through such a dry cycle, it causes polymerization, which is how you make DNA,” Zare argues. Since sources of spray were likely common on the early Earth, Zare thinks this process could produce far more organic chemicals than potential alternatives like lightning strikes, hydrothermal vents, or impacting comets.

But even if micro-lightning really produced the basic building blocks of life on Earth, we’re still not sure how those combined into living organisms. “We did not make life. We just demonstrated a possible mechanism that gives us some chemical compounds you find in life,” Zare says. “It’s very important to have a lot of humility with this stuff.”

Science Advances, 2025. DOI: 10.1126/sciadv.adt8979

Small charges in water spray can trigger the formation of key biochemicals Read More »

In one dog breed, selection for utility may have selected for obesity

behavior, Biology, Dogs, Genetics, Labrador retriever, Science / Kris Guyer / March 14, 2025

High-risk Labradors also tended to pester their owners for food more often. Dogs with low genetic risk scores, on the other hand, stayed slim regardless of whether the owners paid attention to how and whether they were fed or not.

But other findings proved less obvious. “We’ve long known chocolate-colored Labradors are prone to being overweight, and I’ve often heard people say that’s because they’re really popular as pets for young families with toddlers that throw food on the floor all the time and where dogs are just not given that much attention,” Raffan says. Her team’s data showed that chocolate Labradors actually had a much higher genetic obesity risk than yellow or black ones

Some of the Labradors particularly prone to obesity, the study found, were guide dogs, which were included in the initial group. Training a guide dog in the UK usually takes around two years, during which the dogs learn multiple skills, like avoiding obstacles, stopping at curbs, navigating complex environments, and responding to emergency scenarios. Not all dogs are able to successfully finish this training, which is why guide dogs are often selectively bred with other guide dogs in the hope their offspring would have a better chance at making it through the same training.

But it seems that this selective breeding among guide dogs might have had unexpected consequences. “Our results raise the intriguing possibility that we may have inadvertently selected dogs prone to obesity, dogs that really like their food, because that makes them a little bit more trainable. They would do anything for a biscuit,” Raffan says.

The study also found that genes responsible for obesity in dogs are also responsible for obesity in humans. “The impact high genetic risk has on dogs leads to increased appetite. It makes them more interested in food,” Raffan claims. “Exactly the same is true in humans. If you’re at high genetic risk you aren’t inherently lazy or rubbish about overeating—it’s just you are more interested in food and get more reward from it.”

Science, 2025. DOI: 10.1126/science.ads2145

In one dog breed, selection for utility may have selected for obesity Read More »

How whale urine benefits the ocean ecosystem

Biology, Ecology, marine animals, marine ecology, Science, whales / Kris Guyer / March 12, 2025

A “great whale conveyor belt”

illustration showing how whale urine spreads throughout the ocean ecosystem — Credit: A. Boersma

Migrating whales typically gorge in summers at higher latitudes to build up energy reserves to make the long migration to lower latitudes. It’s still unclear exactly why the whales migrate, but it’s likely that pregnant females in particular find it more beneficial to give birth and nurse their young in warm, shallow, sheltered areas—perhaps to protect their offspring from predators like killer whales. Warmer waters also keep the whale calves warm as they gradually develop their insulating layers of blubber. Some scientists think that whales might also migrate to molt their skin in those same warm, shallow waters.

Roman et al. examined publicly available spatial data for whale feeding and breeding grounds, augmented with sightings from airplane and ship surveys to fill in gaps in the data, then fed that data into their models for calculating nutrient transport. They focused on six species known to migrate seasonally over long distances from higher latitudes to lower latitudes: blue whales, fin whales, gray whales, humpback whales, and North Atlantic and southern right whales.

They found that whales can transport some 4,000 tons of nitrogen each year during their migrations, along with 45,000 tons of biomass—and those numbers could have been three times larger in earlier eras before industrial whaling depleted populations. “We call it the ‘great whale conveyor belt,’” Roman said. “It can also be thought of as a funnel, because whales feed over large areas, but they need to be in a relatively confined space to find a mate, breed, and give birth. At first, the calves don’t have the energy to travel long distances like the moms can.” The study did not include any effects from whales releasing feces or sloughing their skin, which would also contribute to the overall nutrient flux.

“Because of their size, whales are able to do things that no other animal does. They’re living life on a different scale,” said co-author Andrew Pershing, an oceanographer at the nonprofit organization Climate Central. “Nutrients are coming in from outside—and not from a river, but by these migrating animals. It’s super-cool, and changes how we think about ecosystems in the ocean. We don’t think of animals other than humans having an impact on a planetary scale, but the whales really do.”

Nature Communications, 2025. DOI: 10.1038/s41467-025-56123-2 (About DOIs).

How whale urine benefits the ocean ecosystem Read More »

“Wooly mice” a test run for mammoth gene editing

Biology, de-extinction, fur, gene editing, Genetics, mammoths, Mice, Science / Rejus Almole / March 5, 2025

On Tuesday, the team behind the plan to bring mammoth-like animals back to the tundra announced the creation of what it is calling wooly mice, which have long fur reminiscent of the woolly mammoth. The long fur was created through the simultaneous editing of as many as seven genes, all with a known connection to hair growth, color, and/or texture.

But don’t think that this is a sort of mouse-mammoth hybrid. Most of the genetic changes were first identified in mice, not mammoths. So, the focus is on the fact that the team could do simultaneous editing of multiple genes—something that they’ll need to be able to do to get a considerable number of mammoth-like changes into the elephant genome.

Of mice and mammoths

The team at Colossal Biosciences has started a number of de-extinction projects, including the dodo and thylacine, but its flagship project is the mammoth. In all of these cases, the plan is to take stem cells from a closely related species that has not gone extinct, and edit a series of changes based on the corresponding genomes of the deceased species. In the case of the mammoth, that means the elephant.

But the elephant poses a large number of challenges, as the draft paper that describes the new mice acknowledges. “The 22-month gestation period of elephants and their extended reproductive timeline make rapid experimental assessment impractical,” the researchers acknowledge. “Further, ethical considerations regarding the experimental manipulation of elephants, an endangered species with complex social structures and high cognitive capabilities, necessitate alternative approaches for functional testing.”

So, they turned to a species that has been used for genetic experiments for over a century: the mouse. We can do all sorts of genetic manipulations in mice, and have ways of using embryonic stem cells to get those manipulations passed on to a new generation of mice.

For testing purposes, the mouse also has a very significant advantage: mutations that change its fur are easy to spot. Over the century-plus that we’ve been using mice for research, people have noticed and observed a huge variety of mutations that affect their fur, altering color, texture, and length. In many of these cases, the changes in the DNA that cause these changes have been identified.

“Wooly mice” a test run for mammoth gene editing Read More »

An small microbial ecosystem has formed on the International Space Station

Biology, Ecology, international space station, microbiome, Science / Tim Belzer / March 3, 2025

“One of the more similar environments to the ISS was in the isolation dorms on the UCSD campus during the COVID-19 pandemic. All surfaces were continuously sterilized, so that microbial signatures would be erased by the time another person would show up,” Benitez said. So, one of the first solutions to the ISS microbial diversity problem he and his colleagues suggested was that they perhaps should ease up on sterilizing the station so much.

“The extensive use of disinfection chemicals might not be the best approach to maintaining a healthy microbial environment, although there is certainly plenty of research to be conducted,” Benitez said.

Space-faring gardens

He suggested that introducing microbes that are beneficial to human health might be better than constantly struggling to wipe out all microbial life on the station. And while some modules up there do need to be sterilized, keeping some beneficial microbes alive could be achieved by designing future spacecraft in a way that accounts for how the microbes spread.

“We found that microbes in modules with little human activity tend to stay in those modules without spreading. When human activity is high in a module, then the microbes spread to adjacent modules,” Zhao said. She said spacecraft could be designed to put modules with high human activity at one end and the modules with little to no human activity at the opposite end, so the busy modules don’t contaminate the ones that need to remain sterile. “We are of course talking as microbiologists and chemists—perhaps spacecraft engineers have more pressing reasons to put certain modules at certain spots,” Zhao said. “These are just preliminary ideas.”

But what about crewed deep space missions to Mars and other destinations in the Solar System? Should we carefully design the microbial composition beforehand, plant the microbes on the spacecraft and hope this artificial, closed ecosystem will work for years without any interventions from Earth?

“I’d take a more holistic ecosystem approach,” Benitez said. He imagines in the future we could build spacecraft and space stations hosting entire gardens with microbes that would interact with plants, pollinators, and animals to create balanced, self-sustaining ecosystems. “We’d not only need to think about sending the astronauts and the machines they need to function, but also about all other lifeforms we will need to send along with them,” Benitez said

Cell, 2025. DOI: 10.1016/j.cell.2025.01.039

An small microbial ecosystem has formed on the International Space Station Read More »

Did the snowball Earth give complex life a boost?

Biology, evolution, geology, glaciers, Science, snowball earth / Paul Patrick / March 2, 2025

Life is complex

But when new minerals made their way to the water, what did they actually do? Cycle throughout the bottom of the ocean, delivering new elements to previously barren locations and providing energy for microbial life. At the end of the Cryogenic, these early lifeforms appear to have gotten gradually more complex, paving the way for the first known multicellular life in the ensuing Ediacaran.

“Any time there’s a really radical environmental shift, we know that’s an interesting time for evolution,” says Chris Kempes, a theoretical biophysicist at the Sante Fe Institute who was not involved in the research. For example, when temperatures drop or less sunlight is available, organisms’ speed and metabolic rates generally slow down, creating new pressures on life, Kempes’ research has found. Halverson thinks the extreme habitats that life had to endure during the snowballs played more of a role in shaping evolution than the nutrient flushes from glaciers.

Even so, studies like Kirkland’s that try to understand how nutrients and energy availability changed throughout history are “the key to understanding when and why there are major evolutionary transitions,” Kempes says.

To determine what other minerals may have been key players in the ancient oceans, Kirkland hopes to look at rocks called apatites, which contain oxygen and other elements like strontium and phosphorus. However, these break down much easier than zircon-rich rocks, meaning they are less stable through long stretches of time.

Though the global changes of the Cryogenic happened eons ago, Kirkland sees parallels with the wide-scale climate changes of today. “The atmosphere, the land, and the oceans are all interconnected,” he says. “Understanding these [ancient] cycles gives us information about how more modern cycles on the planet may work.”

Geology, 2025. DOI: 10.1130/G52887.1

Hannah Richter is a freelance science journalist and graduate of MIT’s Graduate Program in Science Writing. She primarily covers environmental science and astronomy.

Did the snowball Earth give complex life a boost? Read More »

Flashy exotic birds can actually glow in the dark

Biology, bioluminescence, birds, feathers, Fluorescence, Science / Mike M. / February 24, 2025

Found in the forests of Papua New Guinea, Indonesia, and Eastern Australia, birds of paradise are famous for flashy feathers and unusually shaped ornaments, which set the standard for haute couture among birds. Many use these feathers for flamboyant mating displays in which they shape-shift into otherworldly forms.

As if this didn’t attract enough attention, we’ve now learned that they also glow in the dark.

Biofluorescent organisms are everywhere, from mushrooms to fish to reptiles and amphibians, but few birds have been identified as having glowing feathers. This is why biologist Rene Martin of the University of Nebraska-Lincoln wanted to investigate. She and her team studied a treasure trove of specimens at the American Museum of Natural History, which have been collected since the 1800s, and found that 37 of the 45 known species of birds of paradise have feathers that fluoresce.

The glow factor of birds of paradise is apparently important for mating displays. Despite biofluorescence being especially prominent in males, attracting a mate might not be all it is useful for, as these birds might also use it to signal to each other in other ways and sometimes even for camouflage among the light and shadows.

“The current very limited number of studies reporting fluorescence in birds suggests this phenomenon has not been thoroughly investigated,” the researchers said in a study that was recently published in Royal Society Open Science.

Glow-up

How do they get that glow? Biofluorescence is a phenomenon that happens when shorter, high-energy wavelengths of light, meaning UV, violet, and blue, are absorbed by an organism. The energy then gets re-emitted at longer, lower-energy wavelengths—greens, yellows, oranges, and reds. The feathers of birds of paradise contain fluorophores, molecules that undergo biofluorescence. Specialized filters in the light-sensitive cells of their eyes make their visual system more sensitive to biofluorescence.

Flashy exotic birds can actually glow in the dark Read More »

Study: Cuttlefish adapt camouflage displays when hunting prey

animal behavior, Biology, cuttlefish, marine animals, Science / Rejus Almole / February 20, 2025

Crafty cuttlefish employ several different camouflaging displays while hunting their prey, according to a new paper published in the journal Ecology, including mimicking benign ocean objects like a leaf or coral, or flashing dark stripes down their bodies. And individual cuttlefish seem to choose different preferred hunting displays for different environments.

It’s well-known that cuttlefish and several other cephalopods can rapidly shift the colors in their skin thanks to that skin’s unique structure. As previously reported, squid skin is translucent and features an outer layer of pigment cells called chromatophores that control light absorption. Each chromatophore is attached to muscle fibers that line the skin’s surface, and those fibers, in turn, are connected to a nerve fiber. It’s a simple matter to stimulate those nerves with electrical pulses, causing the muscles to contract. And because the muscles are pulling in different directions, the cell expands, along with the pigmented areas, changing the color. When the cell shrinks, so do the pigmented areas.

Underneath the chromatophores, there is a separate layer of iridophores. Unlike the chromatophores, the iridophores aren’t pigment-based but are an example of structural color, similar to the crystals in the wings of a butterfly, except a squid’s iridophores are dynamic rather than static. They can be tuned to reflect different wavelengths of light. A 2012 paper suggested that this dynamically tunable structural color of the iridophores is linked to a neurotransmitter called acetylcholine. The two layers work together to generate the unique optical properties of squid skin.

And then there are leucophores, which are similar to the iridophores, except they scatter the full spectrum of light, so they appear white. They contain reflectin proteins that typically clump together into nanoparticles so that light scatters instead of being absorbed or directly transmitted. Leucophores are mostly found in cuttlefish and octopuses, but there are some female squid of the genus Sepioteuthis that have leucophores that they can “tune” to only scatter certain wavelengths of light. If the cells allow light through with little scattering, they’ll seem more transparent, while the cells become opaque and more apparent by scattering a lot more light.

Scientists learned in 2023 that the process by which cuttlefish generate their camouflage patterns is significantly more complex than scientists previously thought. Specifically, cuttlefish readily adapted their skin patterns to match different backgrounds, whether natural or artificial. And the creatures didn’t follow the same transitional pathway every time, often pausing in between. That means that contrary to prior assumptions, feedback seems to be critical to the process, and the cuttlefish were correcting their patterns to match the backgrounds better.

Study: Cuttlefish adapt camouflage displays when hunting prey Read More »

AI used to design a multi-step enzyme that can digest some plastics

AI, biochemistry, Biology, catalysts, chemistry, Computer science, enzymes, Science / Kris Guyer / February 15, 2025

And it worked. Repeating the same process with an added PLACER screening step boosted the number of enzymes with catalytic activity by over three-fold.

Unfortunately, all of these enzymes stalled after a single reaction. It turns out they were much better at cleaving the ester, but they left one part of it chemically bonded to the enzyme. In other words, the enzymes acted like part of the reaction, not a catalyst. So the researchers started using PLACER to screen for structures that could adopt a key intermediate state of the reaction. This produced a much higher rate of reactive enzymes (18 percent of them cleaved the ester bond), and two—named “super” and “win”—could actually cycle through multiple rounds of reactions. The team had finally made an enzyme.

By adding additional rounds alternating between structure suggestions using RFDiffusion and screening using PLACER, the team saw the frequency of functional enzymes increase and eventually designed one that had an activity similar to some produced by actual living things. They also showed they could use the same process to design an esterase capable of digesting the bonds in PET, a common plastic.

If that sounds like a lot of work, it clearly was—designing enzymes, especially ones where we know of similar enzymes in living things, will remain a serious challenge. But at least much of it can be done on computers rather than requiring someone to order up the DNA that encodes the enzyme, getting bacteria to make it, and screening for activity. And despite the process involving references to known enzymes, the designed ones didn’t share a lot of sequences in common with them. That suggests there should be added flexibility if we want to design one that will react with esters that living things have never come across.

I’m curious about what might happen if we design an enzyme that is essential for survival, put it in bacteria, and then allow it to evolve for a while. I suspect life could find ways of improving on even our best designs.

Science, 2024. DOI: 10.1126/science.adu2454 (About DOIs).

AI used to design a multi-step enzyme that can digest some plastics Read More »

Parrots struggle when told to do something other than mimic their peers

animal behavior, Behavioral science, Biology, parrots, Science / Paul Patrick / February 6, 2025

There have been many studies on the capability of non-human animals to mimic transitive actions—actions that have a purpose. Hardly any studies have shown that animals are also capable of intransitive actions. Even though intransitive actions have no particular purpose, imitating these non-conscious movements is still thought to help with socialization and strengthen bonds for both animals and humans.

Zoologist Esha Haldar and colleagues from the Comparative Cognition Research group worked with blue-throated macaws, which are critically endangered, at the Loro Parque Fundación in Tenerife. They trained the macaws to perform two intransitive actions, then set up a conflict: Two neighboring macaws were asked to do different actions.

What Haldar and her team found was that individual birds were more likely to perform the same intransitive action as a bird next to them, no matter what they’d been asked to do. This could mean that macaws possess mirror neurons, the same neurons that, in humans, fire when we are watching intransitive movements and cause us to imitate them (at least if these neurons function the way some think they do).

But it wasn’t on purpose

Parrots are already known for their mimicry of transitive actions, such as grabbing an object. Because they are highly social creatures with brains that are large relative to the size of their bodies, they made excellent subjects for a study that gauged how susceptible they were to copying intransitive actions.

Mirroring of intransitive actions, also called automatic imitation, can be measured with what’s called a stimulus-response-compatibility (SRC) test. These tests measure the response time between seeing an intransitive movement (the visual stimulus) and mimicking it (the action). A faster response time indicates a stronger reaction to the stimulus. They also measure the accuracy with which they reproduce the stimulus.

Until now, there have only been three studies that showed non-human animals are capable of copying intransitive actions, but the intransitive actions in these studies were all by-products of transitive actions. Only one of these focused on a parrot species. Haldar and her team would be the first to test directly for animal mimicry of intransitive actions.

Parrots struggle when told to do something other than mimic their peers Read More »

Bonobos recognize when humans are ignorant, try to help

Behavioral science, Biology, cooperation, Neuroscience, Science, theory of mind / Mike M. / February 3, 2025

A lot of human society requires what’s called a “theory of mind”—the ability to infer the mental state of another person and adjust our actions based on what we expect they know and are thinking. We don’t always get this right—it’s easy to get confused about what someone else might be thinking—but we still rely on it to navigate through everything from complicated social situations to avoid bumping into people on the street.

There’s some mixed evidence that other animals have a limited theory of mind, but there are alternate interpretations for most of it. So two researchers at Johns Hopkins, Luke Townrow and Christopher Krupenye, came up with a way of testing whether some of our closest living relatives, the bonobos, could infer the state of mind of a human they were cooperating with. The work clearly showed that the bonobos could tell when their human partner was ignorant.

Now you see it…

The experimental approach is quite simple, and involves a setup familiar to street hustlers: a set of three cups, with a treat placed under one of them. Except in this case, there’s no sleight-of-hand in that the chimp can watch as one experimenter places the treat under a cup, and all of the cups remain stationary throughout the experiment.

To get the treat, however, requires the cooperation of a second human experimenter. That person has to identify the right cup, then give the treat under it to the bonobo. In some experiments, this human can watch the treat being hidden through a transparent partition, and so knows exactly where it is. In others, however, the partition is solid, leaving the human with no idea of which cup might be hiding the food.

This setup means that the bonobo will always know where the food is and will also know whether the human could potentially have the same knowledge.

The bonobos were first familiarized with the setup and got to experience their human partner taking the treat out from under the cup and giving it to them. Once they were familiar with the process, they watched the food being hidden without any partner present, which demonstrated they rarely took any food-directed actions without a good reason to do so. In contrast, when their human partner was present, they were about eight times more likely to point to the cup with the food under it.

Bonobos recognize when humans are ignorant, try to help Read More »

Let us spray: River dolphins launch pee streams into air

animal behavior, animal communication, animals, Biology, dolphins, Science / Tim Belzer / February 3, 2025

According to Amazonian folklore, the area’s male river dolphins are shapeshifters (encantade), transforming at night into handsome young men who seduce and impregnate human women. The legend’s origins may lie in the fact that dolphins have rather human-like genitalia. A group of Canadian biologists didn’t spot any suspicious shapeshifting behavior over the four years they spent monitoring a dolphin population in central Brazil, but they did document 36 cases of another human-like behavior: what appears to be some sort of cetacean pissing contest.

Specifically, the male dolphins rolled over onto their backs, displayed their male members, and launched a stream of urine as high as 3 feet into the air. This usually occurred when other males were around, who seemed fascinated in turn by the arching streams of pee, even chasing after them with their snouts. It’s possibly a form of chemical sensory communication and not merely a need to relieve themselves, according to the biologists, who described their findings in a paper published in the journal Behavioral Processes. As co-author Claryana Araújo-Wang of CetAsia Research Group in Ontario, Canada, told New Scientist, “We were really shocked, as it was something we had never seen before.”

Spraying urine is a common behavior in many animal species, used to mark territory, defend against predators, communicate with other members of one’s species, or as a means of mate selection since it has been suggested that the chemicals in the urine carry useful information about physical health or social dominance.

Let us spray: River dolphins launch pee streams into air Read More »