The genetic engineering behind pig-to-human transplants

Image of young pigs in a plastic container.

Enlarge / Cloned piglets that are engineered to be useful for organ transplants to humans. (credit: Getty Images / Staff)

Last week, when we reported on the first pig-to-human heart transplant, we complained that the commercial company behind the operation wasn’t more forthcoming about the genetic engineering that converted the pig into a viable donor.

We now know much more about porcine genetic engineering thanks to a new paper covering a different, more cautious test procedure. The work described in the paper is a transplant of pig kidneys into a brain-dead recipient and is meant to pave the way for trials in viable humans. The publication that describes the work contains extensive details on the genetic engineering used to ensure that the pig tissue would survive in a human host.

A test case

According to The New York Times, the recipient was rendered brain-dead by a motorcycle accident. He had signed up as an organ donor and was kept alive while his organs were screened; his next of kin gave informed consent to his body’s use in the experimental procedure.

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#biology, #genetic-engineering, #medicine, #organ-transplants, #science, #xenotransplants

Study: Female dolphins have a working clitoris, so they probably enjoy sex

Sure, they look like they're just taking a friendly swim, but these two dolphins are actually aroused. A recent study found that female bottlenose dolphins have large erectile bodies that fill up with blood, large nerves with nerve bundles that end right under the skin, thinner skin on the clitoris body, and genital corpuscles known to be involved in the pleasure response.

Enlarge / Sure, they look like they’re just taking a friendly swim, but these two dolphins are actually aroused. A recent study found that female bottlenose dolphins have large erectile bodies that fill up with blood, large nerves with nerve bundles that end right under the skin, thinner skin on the clitoris body, and genital corpuscles known to be involved in the pleasure response. (credit: Dara Orbach)

Female dolphins are known to be highly social and engage in all sorts of sexual behavior. In addition to mating with male dolphins, female bottlenose dolphins are, for instance, known to masturbate and also rub each other’s clitoris with snouts, flippers, and flukes, suggesting the acts are pleasurable for them. According to a recent paper published in the journal Current Biology, there is now anatomical evidence that the dolphin clitoris is fully functional, remarkably similar in many ways to the clitoris in human females.

It’s not just dolphins that engage in what Canadian biologist and linguist Bruce Bagemihl has dubbed “biological exuberance.” Same-sex pairings have been recorded in some 450 different species, including flamingoes, bison, warthogs, beetles, and guppies. For instance, female koalas sometimes mount other females, while male Amazon river dolphins have been known to penetrate each other’s blowholes. The observation of female-female pairs among Laysan albatrosses made national headlines, prompting comedian Stephen Colbert to warn satirically that “albatresbians” were threatening American family values with their “Sappho-avian agenda.” Female hedgehogs may hump one another or perform cunnilingus, while 60 percent of all sexual activity among bonobos takes place between two or more females.

Despite this abundance of behavioral evidence, there have been very few academic studies of the clitoris and female sexual pleasure in nature, according to Patricia Brennan, a marine biologist at Mount Holyoke College in Massachusetts and a co-author of the new study. “This has left us with an incomplete picture of the true nature of sexual behaviors,” she said. “Studying and understanding sexual behaviors in nature is a fundamental part of understanding the animal experience and may even have important medical applications in the future.” It can also yield insights into the evolution of sexual behaviors.

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#anatomy, #animals, #biological-exuberance, #biology, #dolphins, #science, #sexuality

Gene Variant May Have Helped Ancient Humans Survive Starvation

When there’s no food, it pays to be small

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#advances, #biology, #genetics

Immune system vs. virus: Why omicron had experts worried from the start

Illustration of antibodies responding to an infection of SARS-CoV-2.

Enlarge / Illustration of antibodies responding to an infection of SARS-CoV-2. (credit: Getty Images/Kateryna Kon/Science Photo Library)

Right from omicron’s first description, researchers were concerned about the variant of the SARS-CoV-2 virus. Looking over the list of mutations it carried, scientists could identify a number that would likely make the variant more infectious. Other mutations were even more worrying, as they would likely interfere with the immune system’s ability to recognize the virus, allowing it to pose a risk to those who had been vaccinated or suffered from previous infections.

Buried in the subtext of these worries was a clear implication: Scientists could simply look at the sequence of amino acids in the spike protein of a coronavirus and get a sense of how well the immune system would respond to it.

That knowledge is based on years of studying how the immune system operates, combined with a lot of specific information regarding its interactions with SARS-CoV-2. What follows is a description of these interactions, along with their implications for viral evolution and present and future variants.

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#antibodies, #b-cells, #biology, #covid-19, #immunology, #medicine, #pandemic, #sars-cov-2, #science, #t-cells, #vaccines

New Bait Uses Mosquitoes’ Love of Malaria Parasite to Bite Them Back

Molecules produced by the parasite lure mosquitoes to a beet-based bait

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#advances, #animals, #biology

Pig heart transplanted to human for the first time

Image of surgeons surrounding a patient.

Enlarge / The transplant team with the replacement heart. (credit: The transplant team with the replacement heart.)

On Monday, the University of Maryland School of Medicine announced that its staff had done the first transplant of a pig’s heart into a human. The patient who received it had end-stage heart disease and was too sick to qualify for the standard transplant list. Three days after the procedure, the patient was still alive.

The idea of using non-human organs as replacements for damaged human ones—called xenotransplantation—has a long history, inspired by the fact that there are more people on organ waiting lists than there are donors. And, in recent years, our ability to do targeted gene editing has motivated people to start genetically modifying pigs in order to make them better donors. But the recent surgery wasn’t part of a clinical trial, so it shouldn’t be viewed as an indication that this approach is ready for widespread safety and efficacy testing.

Instead, the surgery was authorized by the FDA under its “compassionate use” access program. This allows those faced with life-threatening illnesses to receive investigational treatments that haven’t gone through rigorous clinical testing yet.

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#biology, #gene-editing, #medicine, #science, #transplants, #xenotransplants

Fossils Reveal When Animals Started Making Noise

For billions of years Earth was quiet. Then life got loud

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#animals, #biology, #evolution, #features

The Surprising Physics of Finger Snapping

You might not think that you can generate more body acceleration than a big-league baseball pitcher, but new research shows you can.

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#biology, #physiology

Desert Beetles Rely on Oral Sex for Successful Mating

The more time the insects spend on the courtship ritual, the better mating goes

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#advances, #animals, #biology

Dogs Can Distinguish Speech from Gibberish–and Tell Spanish from Hungarian

A new study’s authors say their investigation represents the first time that a nonhuman brain has been shown to detect language

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#animals, #biology

Virtual 3D models of ammonite fossils show their muscles for first time

Stylized image of nautilus-style creature.

Enlarge (credit: Lesley Cherns et al.)

Researchers created a highly detailed 3D model of a 365-million-year-old ammonite fossil from the Jurassic period by combining advanced imaging techniques, revealing internal muscles that have never been previously observed, according to a paper published last month in the journal Geology. Another paper published last month in the journal Papers in Paleontology reported on the creation of 3D virtual models of the armored plates from fossilized skeletons of two new species of ancient worms, dating from 400 million years ago.

The ammonite fossil used in the Geology study was discovered in 1998 at the Claydon Pike pit site in Gloucestershire, England, which mostly comprises poorly cemented sands, sandstone, and limestone. Plenty of fragmented mollusk shells are scattered throughout the site, but this particular specimen was remarkably intact, showing no signs of prolonged exposure via scavenging, shell encrustation, or of being exhumed from elsewhere and redeposited. The fossil is currently housed at the National Museum Wales, Cardiff.

“When I found the fossil, I immediately knew it was something special,” said co-author Neville Hollingworth, public engagement manager at the Science and Technology Facilities Council. “The shell split in two and the body of the fossil fell out revealing what looked like soft tissues. It is wonderful to finally know what these are through the use of state-of-the-art imaging techniques.”

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#12-days-of-christmas, #3d-virtual-models, #biology, #fossils, #geology, #micro-ct-imaging, #neutron-imaging, #paleobiology, #paleontology, #science

Bacterial Builders Churn Out Lengthy Muscle Proteins

Such proteins can be woven into resilient fibers

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#advances, #biology, #microbiology

Researchers built a gecko-bot to study how geckos glide and crash land

A gecko perches on a leaf. A September study found that geckos are very good gliders, and their tails help stabilize them when they crash-land into tree trunks.

Enlarge / A gecko perches on a leaf. A September study found that geckos are very good gliders, and their tails help stabilize them when they crash-land into tree trunks. (credit: MPI for Intelligent Systems)

There’s rarely time to write about every cool science-y story that comes our way. So this year, we’re once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2020, each day from December 25 through January 5. Today: Asian flat-tails geckos gliding in the wild use their tails to stabilize the landing after colliding head-first into tree trunks.

There are plenty of examples of gliding animals: flying squirrels, for instance, as well as certain snakes, lizards, and frogs. Now we can add geckos to that list. Researchers caught Asian flat-tailed geckos gliding in the wild on high-speed video, and found they used their tails to stabilize the landing after colliding head-first into tree trunks, according to a paper published in September in the journal Nature Communications Biology. They verified the biomechanics by building a mini gecko-bot and simulating the gliding behavior in the lab.

As we’ve reported previously, the diminutive gecko is capable of some extraordinary feats of locomotion, zipping along vertical walls with ease and even running short distances across water. Precisely how they accomplish these feats has long interested scientists. For instance, geckos are known for being expert climbers, able to stick to any surface thanks to the tiny hair-like structures on the bottoms of their feet. The little lizards can also zip along the surface of water at high speeds to elude predators. They can’t do it for very long; the energy expenditure required is too great.

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#animals, #biology, #biomechanics, #engineering, #geckos, #science, #soft-robotics

Could we build a synthetic digestive system for Vision to make him more human?

The birth of Vision in <em>Avengers: Age of Ultron</em>. Scientists have proposed a possible artificial digestive system for the synthezoid, although new technologies must be developed to make it a reality.

Enlarge / The birth of Vision in Avengers: Age of Ultron. Scientists have proposed a possible artificial digestive system for the synthezoid, although new technologies must be developed to make it a reality. (credit: Marvel Studios)

There’s rarely time to write about every cool science-y story that comes our way. So this year, we’re once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2020, each day from December 25 through January 5. Today: How to build a synthetic digestive system for Marvel’s Vision. Bonus: assessing the health status of five Avengers to determine how their health will fare as they age.

The folks at Marvel Studios aren’t the only ones who like to imagine What If…? Inspired by Marvel’s Vision, two scientists reviewed the current state of soft robotics to determine whether it would be possible to build an artificial digestive system for the synthezoid, describing their work a paper published earlier this year in the journal Superhero Science + Technology.  (It’s an open access journal published by TU Delft “that considers new research in the fields of science, technology, engineering and ethics motivated and presented using the superhero genre.”)

Hey, inquiring minds need to know! It’s not just a fun exercise in a more positive form of nerd-gassing, either. The authors note that humanity in general would benefit from advances in such systems, with applications in organ replacement and clinical treatments for patients with chronic digestive issues. 

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#12-days-of-christmas, #avengers-age-of-ultron, #biology, #biomimetics, #digestive-system, #gaming-culture, #marvel-studios, #marvels-avengers, #marvels-vision, #science, #soft-robotics, #superhero-science

Tiny tardigrades walk like insects 500,000 times their size

SEM Micrograph of a tardigrade, commonly known as a water bear

Enlarge / SEM Micrograph of a tardigrade, more commonly known as a water bear or “moss piglet.” (credit: Cultura RM Exclusive/Gregory S. Paulson/Getty Images)

There’s rarely time to write about every cool science-y story that comes our way. So this year, we’re once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2020, each day from December 25 through January 5. Today: the amazing physics of the humble tardigrade.

Is there nothing the tiny tardigrade can’t do? More commonly known as water bears (or “moss piglets”), these amazing micro-animals can survive in the harshest conditions: extreme pressure, extreme temperature, radiation, dehydration, starvation—even exposure in outer space.  That hardiness makes them a favorite case study for scientists.

Earlier this year, researchers at Rockefeller University examined the water bear’s distinctive gait and concluded the creature’s movement resembles that of insects 500,000 times their size, according to a paper published in August in the Proceedings of the National Academy of Sciences.

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#animals, #biology, #biomechanics, #biophysics, #physics, #quantum-entanglement, #quantum-physics, #science, #tardigrades, #water-bears

The Best Fun Science Stories of 2021: Rhythmic Lemurs, a Marscopter and Sex-Obsessed Insect Zombies

Check out the weird and wonderful stories that delighted us this year

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#animals, #biology, #planetary-science, #plants, #robotics

Smokers gave a home to bacteria that now sicken people with cystic fibrosis

Image of a smoking cigarette.

Enlarge (credit: Peter Dazeley / Getty Images)

Smoking can really clog up the lungs, even for people who’ve never been near a cigarette. Turns out that smoking habits from the early 1900s are still inflicting damage—not on tobacco users or their families, but on people with cystic fibrosis.

Cystic fibrosis (CF) is a hereditary condition that makes afflicted people’s mucus thick and sticky. Their lungs become breeding grounds for bacteria that healthy people’s immune systems easily defeat. People with CF often take antibiotics to prevent lung infections, but antibiotics don’t kill everything. A bacterium called Mycobacterium abscessus (M. abscessus) is resistant to many common drugs, and it has become a plague in the CF community over the last couple of decades.

A few years ago, scientists began investigating how the plague originated. By analyzing M. abscessus genomes collected from people around the world, the researchers traced the bacterium’s spread over the last century. They found that decades before the 1950s—before medical advances let people with CF survive past infancy—M. abscessus was already spreading around the globe, and an old public health enemy was to blame. Smokers’ lungs created a reservoir where the pathogen could live and reproduce, a reservoir that quickly spilled over when people with cystic fibrosis began living into adulthood.

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#bacteria, #biology, #cystic-fibrosis, #epidemiology, #infections, #medicine, #science, #smoking

How Did Neanderthals and Other Ancient Humans Learn to Count?

Archaeological finds suggest that people developed numbers tens of thousands of years ago. Scholars are now exploring the first detailed hypotheses about this life-changing invention

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#biology, #evolution, #features

Fish Do the Wave to Ward Off Predatory Birds

The synchronized dances of sulfur mollies is not only mesmerizing to watch, but also confusing to predators

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#animals, #biology, #evolution

Potty Training Cows and Other Messy Stories from the Animal Kingdom

Wombats’ cubic poop, secret pee signals and pandas’ unusual strategy to stay warm

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#advances, #animals, #biology

Secrets of Ultrarare Black Tigers Revealed

Scientists cracked the puzzle behind the mutant tigers’ markings and documented their spread

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#advances, #biology, #genetics

Vaccine trial finds a glitch with children in one age range

Image of a health worker preparing an injection.

Enlarge (credit: Reshi Irshad / Getty Images)

On Friday, Pfizer and BioNTech announced that their latest vaccine trial was showing some odd results in children within a specific age range. Children in the 2- to 5-year age group didn’t produce as strong of an antibody response to the vaccine as older and younger children did. As a result, the trial is being modified to include a third dose of vaccine for participants in this age group.

The trial was designed to enroll as many as 4,500 children to test the safety and efficacy of the companies’ messenger RNA vaccine. It included an early test of how well the vaccine was tolerated in different age groups. Based on these results, the companies went ahead with a two-tiered strategy: children from 5 to 11 years of age got two doses of 10 µg; younger children (down to six months in this trial) received two doses of 3 µg.

The trial is ongoing, and both the participants and doctors involved remain blinded to the status of the participants. But blood samples were obtained from some participants one month after the second dose and analyzed by a separate group of researchers who were not blinded as to the vaccine/placebo status of the participants. The analysis they performed showed an unexpected pattern.

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#biology, #covid-19, #immunology, #medicine, #pandemic, #science, #vaccines

Newfound Millipede Breaks World Record for the Most Legs

It’s a millipede, literally

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#animals, #biology

You asked. Ars answers. Here’s how to give an electric eel an MRI

Veterinarians at Chicago's Shedd Aquarium have pioneered a lot of unusual procedures to diagnosis and treat the animals in their care—including figuring out to give MRIs to electric eels.

Enlarge / Veterinarians at Chicago’s Shedd Aquarium have pioneered a lot of unusual procedures to diagnosis and treat the animals in their care—including figuring out to give MRIs to electric eels. (credit: Aurich Lawson | Getty Images)

Right before Thanksgiving, we reported on how Chicago’s Shedd Aquarium solved the Curious Case of the Missing Chloroquine. The antiparasitic drug is typically added to the water for new animals in quarantine, but it was mysteriously disappearing. The culprit: hungry, hungry microbes. The post included a throwaway line about how the aquarium vets also had the lowdown on how to give an electric eel an MRI.

That bit seemed to resonate with readers, and we received several queries about how, exactly, this feat might be accomplished. You asked. We wanted answers. So we turned to Bill Van Bonn, the clinical veterinarian in charge of the aquarium’s Center for Animal Health and Welfare, which boasts a state-of-the-art animal hospital for monitoring the health of all the animals in the exhibits and treating them as necessary. Dr. Van Bonn and his colleague, Dr. Karisa Tang, were happy to oblige.

Van Bonn describes the veterinary team at the aquarium as “family practitioners” rather than specialists, although they are able to draw on world-class expertise as needed from the greater Chicago area. And since there isn’t a lot of diagnostic and treatment precedent in the literature for many of the animals in their care, they practice comparative medicine by necessity.

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#animals, #biology, #electric-eels, #science, #shedd-aquarium, #veterinary-medicine

Movie-Making Tech Reveals Elephant Trunk Motions

The pachyderms build simple actions into complex movements

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#advances, #animals, #biology

New Clues about the Origins of Biological Intelligence

A common solution is emerging in two different fields: developmental biology and neuroscience

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#biology, #evolution

COVID Variants Hint at How the Virus Will Evolve

The rapid spread of new variants such as Omicron offers clues to how SARS-CoV-2 is adapting and how the pandemic will play out over the next several months

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#biology, #epidemiology, #health, #public-health

To See Where a Whale Has Been, Look in Its Mouth

The baleen that hangs from the jaws of some whale species contains clues about their migrations and diets

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#animals, #biology, #ecology

The Ups and Downs of a Great Vertical Migration

Research is shedding light on why many water dwellers, from plankton to large fish, commute daily from the depths to the surface

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#animals, #biology

Cells or Drugs? The Race to Regenerate the Heart

Researchers are debating how to convince the heart to heal itself instead of laying down scar tissue after a heart attack

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#biology, #health, #medicine

Is There More to a Healthy-Heart Diet Than Cholesterol?

A high-fat diet is thought to increase the risk of a heart attack. But some say that the long-held dogma of “bad” cholesterol might be flawed

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#biology, #health, #medicine

Immune Cells That Remember Inflammation Could Offer Treatment Targets for Atherosclerosis

A type of immune-cell priming called trained immunity is helping researchers to understand the disease mechanisms behind the buildup of fatty deposits in arteries

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#biology, #health, #medicine

Ranking the Risk of Heart Disease

By accounting for the additive effect of multiple genetic variants, researchers can develop a system that improves their ability to identify the most vulnerable

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#biology, #genetics

Humans Are Doomed to Go Extinct

Habitat degradation, low genetic variation and declining fertility are setting Homo sapiens up for collapse 

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#biology, #evolution, #genetics, #reproduction

Interesting research, but no, we don’t have living, reproducing robots

Clusters of frog cells look like beignets.

Enlarge / The crescent-shaped balls of cells would travel in circles, piling up cells that could grow into mobile clusters. (credit: Sam Kriegman and Douglas Blackiston)

Scientists on Monday announced that they’d optimized a way of getting mobile clusters of cells to organize other cells into smaller clusters that, under the right conditions, could be mobile themselves. The researchers call this process “kinematic self-replication,” although that’s not entirely right—the copies need help from humans to start moving on their own, are smaller than the originals, and the copying process grinds to a halt after just a couple of cycles.

So, of course, CNN headlined its coverage “World’s first living robots can now reproduce.”

This is a case when something genuinely interesting is going on, but both the scientists and some of the coverage of the developments are promoting it as far more than it actually is. So, let’s take a look at what’s really been done.

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#bioengineering, #biology, #computer-science, #science, #synthetic-biology

The Surprising Architecture in Bees’ Honeycombs

The insects’ hives are more complicated than researchers thought

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#advances, #animals, #biology

Why Omicron quickly became a variant of concern

That's a lot of mutations.

Enlarge / That’s a lot of mutations. (credit: Stanford)

On Friday, the World Health Organization officially named a new version of the SARS-CoV-2 virus a variant of concern, and attached the Greek letter omicron to the designation. The Omicron variant is notable for the sheer number of mutations in the spike protein of the virus. While Omicron appears to have started spreading in Africa, it has already appeared in European countries like Belgium and the UK, which are working to limit its spread through surveillance and contact tracing.

As of now, the data on the variant is very limited; we don’t currently know how readily it spreads compared to other variants, nor do we understand the degree of protection against Omicron offered by vaccines or past infections. The new designation, however, will likely help focus resources on studying Omicron’s behavior and tracing its spread.

Many changes

While the Delta variant’s version of spike has nine changes compared to the virus that started the pandemic, Omicron has 30 differences. While many of these haven’t been identified previously, a number of these have been seen in other strains, where they have a variety of effects. These include increasing infectiveness of the virus, as a number of the changes increase the affinity between the spike protein and the protein on human cells that it targets when starting a new infection.

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#biology, #medicine, #omicron, #pandemic, #sars-cov-2, #science, #virology

Redo of a Famous Experiment on the Origins of Life Reveals Critical Detail Missed for Decades

The Miller-Urey experiment showed that the conditions of early Earth could be simulated in a glass flask. New research finds the flask itself played an under appreciated, though outsized role.

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#biology, #evolution

Why We Didn’t Know That Female Birds Sing

Science and science communication are better when they’re inclusive

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#biology, #sexgender

Why It Took So Long to Appreciate Female Birds’ Songs

Science and science communication miss out when they’re not inclusive

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#biology, #sexgender

The Surprising Secret of Snakes’ Venomous Bites

Fangs evolved over and over because of this groovy process

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#advances, #animals, #biology, #evolution

Physical Activity Could Be an Evolutionary Adaptation for Grandparenting

It may force energy shifts to repair and maintenance, which could slow aging and make us more available to care for younger generations

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#biology, #evolution

Albatross ‘Divorce’ Rate Rises as the Ocean Warms

Monogamous black-browed albatross may split up from the stress of less food availability

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#animals, #biology, #climate-change, #environment

“Vulture bees” evolved a taste for flesh—and their microbiomes reflect that

Jungle insects crawl over a hunk of pink flesh.

Enlarge / University of California, Riverside scientists suspended fresh pieces of raw chicken from branches to attract carrion-feeding “vulture bees” in Costa Rica. (credit: Quinn McFrederick/UCR)

Ask a random person to picture a bee, and they’ll likely conjure up the familiar black-and-yellow striped creature buzzing from flower to flower collecting pollen to bring back to the hive. But a more unusual group of bees can be found “slicing chunks of meat from carcasses in tropical rainforests,” according to the authors of a new paper published in the journal mBio. As a result, these bees have gut microbiomes that are markedly different from their fellow buzzers, with populations more common to carrion-loving hyenas and vultures. So they are commonly known as “vulture bees” (or “carrion bees”).

According to the authors—entomologists who hail from the University of California, Riverside (UCR), the University of Massachusetts, Amherst, Columbia University, and the American Museum of Natural History—most bees are essentially “wasps that switched to a vegetarian lifestyle.” But there are two recorded examples of bumblebees feeding on carrion dating back to 1758 and 1837, and some species are known to occasionally feed on carrion in addition to foraging for nectar and pollen. (They are considered “facultatively necrophages,” as opposed to vulture bees, which are deemed “obligate necrophages” because they only eat meat.)

An entomologist named Filippo Silvestri identified the first “vulture bee” in 1902 while analyzing a group of pinned specimens, although nobody called it that since they didn’t know at the time that this species fed on carrion. Silvestri dubbed it Trigona hypogea, and he also described their nests as being used for honey and pollen, although later researchers noted a surprising absence of pollen. Rather, biochemical analysis revealed the presence of secretions similar to those fed to queen bees in the nests of honeybees.

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#bees, #biology, #entomology, #microbiology, #microbiome, #science, #vulture-bees

Metamorphosis: Scientists watch butterfly wings grow inside chrysalis in real time

Close-up photograph of gorgeous butterfly.

Enlarge / A painted lady butterfly lands on a flower. The bright iridescent colors in its wings don’t come from pigment molecules but from how the wings are structured. Chitin scales essentially form a diffraction grating tuned to specific wavelengths of light. (credit: Mark Rightmire / Getty Images)

One of the best-known poems by Gerard Manley Hopkins opens with a tribute to the phenomenon of iridescence. It’s represented by the colorful wings of kingfishers and dragonflies in Hopkins’ poem, but iridescence can also be found in the wings of cicadas and butterflies, in certain species of beetle, and in the brightly colored feathers of male peacocks. Now, a team of researchers at MIT have captured on video the unique structural growth of butterfly wings—continuously, as a butterfly develops inside its chrysalis—for the very first time. The researchers described their findings in a new paper published in the journal Proceedings of the National Academy of Sciences.

As I’ve written previously, the bright iridescent colors in butterfly wings don’t come from any pigment molecules but from how the wings are structured. It’s a naturally occurring example of what physicists call photonic crystals. The scales of chitin (a polysaccharide common to insects) are arranged like roof tiles. Essentially, they form a diffraction grating, except photonic crystals only produce certain colors, or wavelengths, of light, while a diffraction grating will produce the entire spectrum, much like a prism.

Also known as photonic bandgap materials, photonic crystals are “tunable,” which means they are precisely ordered in such a way as to block certain wavelengths of light while letting others through. Alter the structure by changing the size of the tiles, and the crystals become sensitive to a different wavelength. (In fact, the rainbow weevil can control both the size of its scales and how much chitin is used to fine-tune those colors as needed.)

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#animals, #biology, #butterflies, #mechanical-engineering, #metamorphosis, #photonic-crystals, #science, #structural-color

Do Childhood Colds Help the Body Respond to COVID?

A mechanism known as “original antigenic sin” protects some people from flu; whether it helps immune reactions to coronaviruses is still unclear

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#biology, #epidemiology, #health, #microbiology, #public-health

Herpesviruses steal one cell’s protein, use it to infect another

Image of a black circle surrounded by small grey spheres.

Enlarge / Herpes viruses getting ready to infect new cells. (credit: Thierry Work, USGS)

One of the defining features of viruses is that they rely on host proteins in order to reproduce. A host cell will often copy viral genes into RNAs and then translate those RNAs into proteins, for example. Typically, a mature virus that’s ready to spread to another cell has little more than viral proteins, the virus’s genetic material, and maybe some of the host’s membrane. It doesn’t need much else; all the proteins it needs to reproduce further should be present in the next cell it infects.

But some data released this week may have found an exception to this pattern. Members of the herpesvirus family appear to latch on to a protein in the first cell they infect and then carry this protein along with them to the next cell. This behavior might be helpful because of the normal targets of herpesviruses—neurons, which have a very unusual cell structure.

A long way to the nucleus

Like other viruses, herpesviruses start off by infecting cells that are exposed to the environment. But from there, they move on to nerve cells, where they take up residency, persisting even when there’s no overt indications of infection. These infected cells then serve as a launching point for re-establishing active infections, causing lifetime problems for anyone unfortunate enough to have been infected.

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#biochemistry, #biology, #herpes, #science, #virology, #virus

Autism affects the microbiome, not the other way around

Image of reddish rod shaped bacteria on a rough blue background.

Enlarge / False color image of bacteria on a human tongue. (credit: STEVE GSCHMEISSNER/ Getty Images)

An altered microbiome has been associated with—and thereby either implicitly or explicitly implicated as a partial cause of—a wide range of human maladies. These include immune disorders like celiac disease, asthma, and diabetes; obesity; cancers; psychiatric disorders like depression and Alzheimer’s disease; and Autism Spectrum Disorders (ASD). It’s been tied to so many things that Jonathan Eisen felt compelled to start the Overselling the Microbiome Awards.” He had to compile the list for years, even though he’s an evolutionary biologist who truly acknowledges and understands the vital role our microbiome plays in our health.

The notion that an altered microbiome can be a causative factor in ASD comes from studies with mice, in which transferring gut flora from humans with ASD into mice generated social deficits and behavioral abnormalities in the animals. But evidence in humans had issues, so a group of Australian scientists who shared Eisen’s wariness, led by Jacob Gratten, decided to perform a rigorous test of the idea. 

A failure to replicate

The Australian team knew that ASD is often associated with GI symptoms and realized that it is tempting to look for and even assume an intestinal component to the disorder. But they note that the human studies linking an altered microbiome to ASD are pretty weak: they are small, they are biased and fail to consider confounding variables, and they are poorly designed and analyzed. Moreover, the researchers write, “a meta-analysis of human microbiota-associated animal studies has raised concerns that the sheer extent of positive findings is implausible.” 

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#autism, #behavioral-science, #biology, #microbiome, #science

We know what invasive species can do on Earth—what about in space?

Europa could harbor complex life, and we'll have to take care to avoid any cross-contamination.

Europa could harbor complex life, and we’ll have to take care to avoid any cross-contamination. (credit: Ted Stryk/NASA)

The Beresheet crash landed on Earth’s Moon in 2019. Part of the ill-fated Israeli lunar lander’s payload was a bunch of tardigrades, or “water bears.” These organisms are under a millimeter long and can survive extreme cold and radiation by expelling nearly all their moisture before entering a nearly death-like state. The Beresheet tardigrades may have survived the crash and could, potentially, be resurrected by being reintroduced to water.

The tardigrades—sometimes called moss piglets—are safely asleep and probably not running amok on the surface of the Moon. But, in general, scientists, governments, and space agencies around the world agree that bringing Earth’s life to extraterrestrial locales, or vice versa, isn’t great.

A new paper builds on the growing body of literature about this cosmic no-no and draws on the burgeoning field of invasion science—the research of how, on Earth, non-native species spread to and alter new locations. The zebra mussel’s spread across North America through its ability to outcompete native species is a classic example.

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#biology, #invasion-science, #microbes, #nasa, #science, #space, #space-exploration

Mystery of Doomed Sardine Migration Is Finally Solved

Pulses of cold seawater mislead millions of sardines into swimming along the South African coast to their death

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#animals, #biology