Some lizards shed their still-wriggling tails to distract predators, but sea cucumbers take this sort of strategy to the next level. Some startled sea cucumbers shoot a silky — and sticky — substance out of their rear ends that is actually an entire organ.

The tangle of tubules looks like intestines, but it evolved from the invertebrates’ respiratory system, and, like lizard tails, it regenerates after use. In a new study in the April 10 Proceedings of the National Academy of Sciences, researchers delved into the black sea cucumber’s genome to see how the stringlike tubules, called the Cuvierian organ, work at the molecular level.
The black sea cucumber (Holothuria leucospilota) is “the most dominant sea cucumber species in the South China Sea,” says Ting Chen, a biologist at the South China Sea Institute of Oceanology in Guangzhou. “We would like to know what evolutionary advantage this sea cucumber has gained … so that its population can expand so widely and predominantly.”
So the team analyzed the sea cucumber’s entire genome, or genetic instruction book, and focused on genes from the Cuvierian organ because it’s such an odd structure. Then the team predicted what proteins would be made from Cuvierian organ genes using a program called AlphaFold (SN: 9/23/22). Some unexpected predicted proteins were new types of receptors on cells’ surfaces that may play a role in expelling the organ.

The team also found that the “silk” proteins of sea cucumbers’ tubules don’t contain the same sequences of amino acids seen in spider silk, but are similarly made up of long repeated chains of amino acids. This finding hints that these long repeats might be a shared structure across silklike proteins, even when those proteins evolved independently.

What’s more, Chen says, is that the organ’s stickiness — which stops sea cucumber predators like fish, crabs and starfish in their tracks — comes from proteins that have features similar to amyloids. Amyloids are associated with many diseases in humans, including neurodegenerative conditions like Alzheimer’s (SN: 9/9/15).

This paper not only highlights unexpected proteins that are specific to the Cuvierian tubules, says Patrick Flammang, a biologist at the University of Mons in Belgium who was not involved with the study. It also provides a lot of data that can be used to answer other questions about how the enigmatic organ evolved, he says.

And the usefulness of a high-quality genome doesn’t stop there. “We need genomic data for our studies on the reproductive, endocrine, immune and digestive systems of H. leucospilota,” Chen says. The team, he says, is now investigating the genetics behind how the sea cucumbers detect light and digest food.

A good genome, Flammang says, is “a cornerstone to be able to do this work.”

To understand the human brain, take note of the rare, the strange and the downright spooky. That’s the premise of two new books, Unthinkable by science writer Helen Thomson and The Disordered Mind by neuroscientist Eric R. Kandel.

Both books describe people with minds that don’t work the same way as everyone else’s. These are people who are convinced that they are dead, for instance; people whose mental illnesses lead to incredible art; people whose memories have been stolen by dementia; people who don’t forget anything. By scrutinizing these cases, the stories offer extreme examples of how the brain creates our realities.
In the tradition of the late neurologist Oliver Sacks (SN: 10/14/17, p. 28), Thomson explores the experiences of nine people with unusual minds. She travels around the world to interview her subjects with compassion and curiosity. In England, she meets a man who, following a bathtub electrocution, became convinced that he was dead. (Every so often, he still feels “a little bit dead,” he tells Thomson.) In Los Angeles, she spends time with a 64-year-old man who can remember almost every day of his life in extreme detail. And in a frightening encounter in a hospital in the United Arab Emirates, she interviews a man with schizophrenia who transmogrifies into a growling tiger. By visiting them in their element, Thomson presents these people not as parlor tricks, but as fully rendered human beings.
Kandel chooses the brain disorders themselves as his subjects. He explains the current neuroscientific understanding of autism, depression and schizophrenia, for example, by weaving together the history of the research and human examples. His chapter on dementia and memory is particularly compelling, given his own Nobel Prize–winning role in revealing how brains form memories (SN: 10/14/00, p. 247).

With diagrams of key brain regions, Alzheimer’s plaques and even chromosomes, Kandel’s book reads in some ways as a primer on the basic tenets of biology and neuroscience. Also included are stories of people, such as a woman who describes her bipolar illness in stark terms: “Feelings of ease, intensity, power, well-being, financial omnipotence and euphoria pervade one’s marrow.” But then, she says, everything changes. “You are irritable, angry, frightened, uncontrollable and enmeshed totally in the blackest caves of the mind. You never knew those caves were there. It will never end, for madness carves its own reality.”

Though these cases seem extreme, Thomson and Kandel relate unusual brains to more common forms of thinking. Observing huge emotional swings that come with bipolar disorder can help inform scientists about more mundane changes in our happiness or sorrow. Figuring out why a person thinks he’s dead could reveal how we more generally create our sense of self. Understanding why someone might remember everything, or nothing, could help us understand how memories physically change the brain (SN: 2/3/18, p. 22).

By connecting these strange brains to everyday mental processes, both books make clear how much we all have in common, and more than that, how all our brains are a little bit unusual.

Some snippets of RNA can be a real pain.

A microRNA called miR-30c-5p contributes to nerve pain in rats and people, a new study finds. A different microRNA, miR-711, interacts with a well-known itch-inducing protein to cause itching, a second study concludes. Together, the research highlights the important role that the small pieces of genetic material can play in nerve cell function, and may help researchers understand the causes of chronic nerve pain and itch.
MicroRNAs help regulate gene activity and protein production. The small molecules play a big role in controlling cancer (SN: 8/28/10, p. 18) and other aspects of health and disease (SN: 2/20/16, p. 18). Usually, microRNAs work by pairing up with bigger pieces of RNA called messenger RNAs, or mRNA. Messenger RNAs contain copies of genetic instructions that are read by cellular machinery to build proteins. When microRNAs glom onto the messengers, the mRNA can be degraded or the microRNAs can prevent the protein-building machinery from reading the instructions. Either way, the result is typically to dial down production of certain proteins.

In the case of nerve pain, miR-30c-5p limits production of an important protein called TGF-beta that’s involved in controlling pain, María Hurlé, a pharmacologist at the University of Cantabria in Santander, Spain, and colleagues report August 8 in Science Translational Medicine. The researchers discovered the link in experiments with mice, rats and people.

In the rat experiments, researchers cut the sciatic nerve in the thigh, making the rodents more sensitive to pain caused by heat or cold. These rats had more miR-30c-5p in their blood and cerebral spinal fluid than uninjured rats did, Hurlé and colleagues found. And the amount of the microRNA in the rats’ blood correlated with their pain sensitivity. People with nerve pain caused by a lack of blood flow to a limb also had elevated levels of the microRNA in their blood and spinal fluid.
Hurlé’s group confirmed that the microRNA was causing pain by injecting uninjured rats with miR-30c-5p
or an imposter microRNA. Those rats that got the imposter injected into their brains had normal pain sensitivity, but rodents shot up with miR-30c-5p became sensitive to cold pain. Researchers also blocked miR-30c-5p by using another piece of RNA that would latch onto it and prevent it from interacting with the mRNA for TGF-beta. Pain-sensitive rats that got the blocker RNA recovered normal pain responses. “This was a spectacular result,” Hurlé says.
But the finding doesn’t mean that doctors can treat nerve pain by blocking the microRNA in people, she says. Both the microRNA and TGF-beta do too many other important jobs throughout the body to mess with them. The research, however, does suggest that the level of miR-30c-5p in people’s blood and spinal fluid might be a good indicator of nerve pain.

Having a nerve pain indicator would be useful, says Marzia Malcangio, a neuropharmacologist at King’s College London who was not involved in either study. Pain doctors don’t know of any biological molecules that can distinguish nerve pain from pain caused by inflammation or other causes, Malcangio says. Making that distinction is important because different types of pain are treated differently.

A different microRNA, miR-711, seems to be the culprit causing chronic itching in people with lymphoma, neurobiologist and pain researcher Ru-Rong Ji and colleagues report in the Aug. 8 Neuron.

Cancerous immune cells called T-cells secrete miR-711, the team showed in experiments with mice. And giving mice the microRNA by itself made the rodents scratch. Surprisingly, the researchers found, the microRNA gloms onto a well-known pain and itch sensing protein called TRPA1 outside of a cell, instead of binding to an mRNA inside a cell like other microRNAs.

That finding may be a big advance in understanding how itch works, Malcangio says. Chemicals that trigger TRPA1 from inside a nerve cell open a floodgate that allows calcium to pour in and launch a pain signal. Tickling TRPA1 with the microRNA on the outside of the cell causes just a trickle of calcium into the nerve, producing itch instead of pain, Ji, of Duke University School of Medicine, and colleagues propose.

The team designed a peptide (a small protein or portion of a protein) that could block miR-711 from binding to TRPA1. Itchy mice that got the blocking peptide scratched about half as often as mice that got miR-711 injections alone.

Ji thinks the blocking peptide may be able to reduce itch in lymphoma patients, but the team needs to do more research before giving it to people. About a third of Hodgkin’s lymphoma patients and 15 percent of people with non-Hodgkin’s lymphoma have severe itching. The researchers are also investigating whether the microRNA is involved in other types of itchy conditions, such as eczema.

Landing sites on the asteroid Ryugu for the Hayabusa2 spacecraft and its hitchhiking landers have been picked out, scientists with Japan’s Aerospace Exploration Agency announced in a news conference on August 23.

Hayabusa2 arrived at the 1,000-meter-wide asteroid on June 27, and has been scanning the surface since. More than 100 mission team members met on August 17 to choose the first spots for the spacecraft to land.

The team decided that the two landers, called MINERVA-II and MASCOT, will touch down on the diamond-shaped asteroid’s surface first. MINERVA-II, which carries small hopping rovers equipped with cameras and other instruments, will land at a spot near Ryugu’s north pole on September 21. MASCOT, a tumbling rover, will land closer to the south pole on October 4. The craft will roam the landscape making measurements of the asteroid’s composition, temperature and magnetic properties.
The main body of Hayabusa2 will join them in late October, touching down at a point near the asteroid’s equator and gathering a sample of dust there.

The mission team looked for regions 100 meters in diameter that were relatively flat, with slopes less than 30 degrees and with few boulders. Ryugu turned out to be strewn with more boulders than expected based on the first Hayabusa mission, which brought back bits of a smoother asteroid called Itokawa.

But the observations from orbit suggest Ryugu’s surface is well-mixed, meaning that no matter where Hayabusa2 lands, it has a good chance of picking up something interesting. The spacecraft will collect samples from two other, still unknown sites over the next 15 months before returning the samples to Earth in 2020.

A firefly’s blinking behind is more than just a pretty summer sight.

It’s known that fireflies flash to attract mates (SN Online: 8/12/15) — but the twinkles may serve another purpose as well. Jesse Barber, a biologist at Boise State University, had a hunch that the lights also warn off potential nighttime predators. He wasn’t the first person with this hypothesis. As far back as 1882, entomologist G.H. Bowles wrote of fireflies: “May not the light then serve … as a warning of their offensiveness to creatures that would devour them?” But the theory hadn’t been tested, until now. “We always assumed that bats don’t use vision for much,” Barber says.
Many species of fireflies are “chemically protected,” meaning they taste awful to predators, Barber says. Yet if an insect doesn’t offer a warning of its bad taste, it may get sampled anyway. Barber noticed that, unlike moths, which signal their toxicity to bats with noises, fireflies don’t make a peep (SN Online: 7/3/13). He wondered if lightning bugs were warning bats of their disgusting taste with their blinking lights.
Barber and colleagues wanted to see if it took bats longer to learn to avoid fireflies when the flashings were masked. The team began by introducing fireflies to three bats that had never encountered the bugs before. The bats learned to avoid the bright creatures “after just a few interactions,” Barber says. Those early exchanges went something like: catch, taste, drop. Soon, the bats avoided the fireflies completely.
Next came the tricky part: The team needed flying fireflies that wouldn’t blink. Painstakingly, the researchers secured each firefly with a minuscule paper belt under a microscope, and, with a tiny brush, applied two coats of black paint to the flashing back end. Each bug rump — they painted dozens — took about 45 minutes to cover. That’s one of the reasons the experiment took three years, Barber jokes.
But the work paid off: When the researchers exposed a new set of bats to the darkened fireflies, the bats took about twice as long to learn that the bugs had an awful taste.

Those bats that eventually learned to avoid the dark fireflies may have sensed the insects’ distinctive straight-line flight pattern via echolocation, the researchers hypothesize. Bats may avoid fireflies through a combination of senses, echolocation to sense the insects’ flight patterns and vision to glimpse those double-duty flashers.

The sleepy sun turns out to be a factory of extremely energetic light.

Scientists have discovered that the sun puts out more of this light, called high-energy gamma rays, overall than predicted. But what’s really weird is that the rays with the highest energies appear when the star is supposed to be at its most sluggish, researchers report in an upcoming study in Physical Review Letters. The research is the first to examine these gamma rays over most of the solar cycle, a roughly 11-year period of waxing and waning solar activity.
That newfound oddity is probably connected to the activity of the sun’s magnetic fields, the researchers say, and could lead to new insights about the mysterious environment.

“The almost certain thing that’s going on here is the magnetic fields are much more powerful, much more variable, and much more weirdly shaped than we expect,” says astrophysicist John Beacom of the Ohio State University in Columbus.
The sun’s high-energy gamma rays aren’t produced directly by the star. Instead, the light is triggered by cosmic rays — protons that zip through space with some of the highest energies known in nature
— that smack into solar protons and produce high-energy gamma rays in the process ( SN: 10/14/27, p. 7 ) .
All of those gamma rays would get lost inside the sun, if not for magnetic fields. Magnetic fields are known to take charged particles like cosmic rays and spin them around like a house in a tornado. Theorists have predicted that cosmic rays whose paths have been scrambled by the tangled mass of magnetic fields at the solar surface should send high-energy gamma rays shooting back out of the sun, where astronomers can see them.

Beacom and colleagues, led by astrophysicist Tim Linden of Ohio State, sifted through data from NASA’s Fermi Gamma-ray Space Telescope from August 2008 to November 2017. The observations spanned a period of low solar activity in 2008 and 2009, a period of higher activity in 2013 and a decline in activity to the minimum of the next cycle, which started in 2018 (SN: 11/2/13, p. 22). The team tracked the number of solar gamma rays emitted per second, as well as their energies and where on the sun they came from.

There were more high-energy gamma rays, above 50 billion electron volts, or GeV, than anyone predicted, the team reports. Weirder still, rays with energies above 100 GeV appeared only during the solar minimum, when the sun’s activity level was low. One photon emitted during the solar minimum had an energy as high as 467.7 GeV.

Strangest of all, the sun seems to emit gamma rays from different parts of its surface at different times in its cycle. Because cosmic rays that hit the sun come in from all directions, you would expect the entire sun to light up in gamma rays uniformly. But Beacom’s team found that during the solar minimum, gamma rays came mainly from near the equator, and during the solar maximum, when the sun’s activity level was high, they clustered near the poles.

“All of these things are way more weird than anyone had predicted,” Beacom says. “And that means the magnetic fields must be way more weird than anyone had thought.”
Beacom and colleagues tried to connect the excess gamma rays to other solar behaviors that change with magnetic activity, like solar flares or sunspots (SN: 9/30/17, p. 6). “So far nothing has really held up to any sort of scrutiny,” says astrophysicist Annika Peter, also at Ohio State.

High-energy gamma rays may offer a new way to probe the magnetic fields in the uppermost layer of the solar surface, called the photosphere. “You can’t see [the fields] with a telescope,” Beacom says. “But these [cosmic rays] are journeying there, and the gamma rays they send back are messengers of the terrible conditions there.”

More observations are coming soon. NASA’s Parker Solar Probe, which launched on August 12, will take the first direct measurements of the magnetic field in the sun’s outer atmosphere, or corona (SN: 7/21/18, p. 12). And as the sun enters the next solar minimum, the highest-energy gamma rays are starting to return. In February, Fermi caught its first gamma ray with an energy above 100 GeV since 2009.

“There really is something strange afoot,” says solar physicist Craig DeForest of the Southwest Research Institute, who is based in Boulder, Colo., and was not involved in the work. “When there’s some new discovery, scientists don’t shout ‘Eureka!’ They go, ‘Hm, that’s funny. That can’t be right.’ This is a classic case of that.”

A new material that converts light into heat could be laminated onto airplanes, wind turbines, rooftops and offshore oil platforms to help combat ice buildup.

This deicer, called a photothermal trap, has three layers: a top coating of a ceramic-metal mix that turns incoming light into thermal energy, a middle layer of aluminum that spreads this heat across the entire sheet — warming up even areas not bathed in light — and a foam insulation base. The photothermal trap, described online August 31 in Science Advances, can be powered by sunshine or LEDs.

Engineer Susmita Dash of the Indian Institute of Science in Bengaluru and colleagues laid a 6.3-centimeter-wide sheet of the deicing material out in the sun on a day averaging about –3.5° Celsius, alongside a sheet of aluminum. Within four minutes, the photothermal trap heated to about 30° C, while the aluminum warmed to only about 6° C. After five minutes, snow on the surface of the photothermal trap had mostly melted off, but snow remained caked on the aluminum.

Deicing surfaces typically involves energy-intensive heating systems or environmentally unfriendly chemical sprays. By harnessing light to melt ice away, the new photothermal trap may provide a more sustainable means of keeping surfaces ice-free. “This is a new direction for anti-icing,” says Kevin Golovin, a materials scientist and engineer at the University of British Columbia in Kelowna not involved in the work.

New images of gas churning inside an ancient starburst galaxy help explain why this galactic firecracker underwent such frenzied star formation.

Using the Atacama Large Millimeter/submillimeter Array, or ALMA, researchers have taken the most detailed views of the disk of star-forming gas that permeated the galaxy COSMOS-AzTEC-1, which dates back to when the universe was less than 2 billion years old. The telescope observations, reported online August 29 in Nature, reveal an enormous reservoir of molecular gas that was highly susceptible to collapsing and forging new stars.
COSMOS-AzTEC-1 and its starburst contemporaries have long puzzled astronomers, because these galaxies cranked out new stars about 1,000 times as fast as the Milky Way does. According to standard theories of cosmology, galaxies shouldn’t have grown up fast enough to be such prolific star-formers so soon after the Big Bang.

Inside a normal galaxy, the outward pressure of radiation from stars helps counteract the inward pull of gas’s gravity, which pumps the brakes on star formation. But in COSMOS-AzTEC-1, the gas’s gravity was so intense that it overpowered the feeble radiation pressure from stars, leading to runaway star formation. The new ALMA pictures unveil two especially large clouds of collapsing gas in the disk, which were major hubs of star formation.
“It’s like a giant fuel depot that built up right after the Big Bang … and we’re catching it right in the process of the whole thing lighting up,” says study coauthor Min Yun, an astronomer at the University of Massachusetts Amherst.

Yun and colleagues still don’t know how COSMOS-AzTEC-1 stocked up such a massive supply of star-forming material. But future observations of the galaxy and its ilk using ALMA or the James Webb Space Telescope, set to launch in 2021, may help clarify the origins of these ancient cosmic monsters (SN Online: 6/11/14).

Obesity can affect brainpower, and a study in mice may help explain how.

In the brains of obese mice, rogue immune cells chomp nerve cell connections that are important for learning and memory, scientists report September 10 in the Journal of Neuroscience. Drugs that stop this synapse destruction may ultimately prove useful for protecting the brain against the immune cell assault.

Like people, mice that eat lots of fat quickly pack on pounds. After 12 weeks of a high-fat diet, mice weighed almost 40 percent more than mice fed standard chow. These obese mice showed signs of diminished brainpower, neuroscientist Elizabeth Gould of Princeton University and colleagues found. Obese mice were worse at escaping mazes and remembering an object’s location than mice of a normal weight.
On nerve cells, microscopic knobs called dendritic spines receive signals. Compared with normal-sized mice, obese mice had fewer dendritic spines in several parts of the mice’s hippocampi, brain structures important for learning and memory.

The dendritic spine destruction comes from immune cells called microglia, the results suggest. In obese mice, higher numbers of active microglia lurked among these sparser nerve cell connections compared with mice of normal weights. When the researchers interfered with microglia in obese mice, dendritic spines were protected and the mice’s performance on thinking tests improved.

Figuring out ways to stop microglia’s damage might one day prove to protect against obesity-related brain trouble, a concern relevant to the estimated 650 million obese adults worldwide. Obese people are also at a higher risk of dementias such as Alzheimer’s, and some researchers suspect microglia may be a culprit in those brain diseases more generally.

I’m relatively new to Oregon, but one of the ways I know I’m starting to settle in is my ability to recognize marijuana shops. Some are easy. But others, with names like The Agrestic and Mr. Nice Guy, are a little trickier to identify for someone who hasn’t spent much time in a state that has legalized marijuana.

A growing number of states have legalized both medical and recreational marijuana. At the same time, women who are pregnant or breastfeeding are using the drug in increasing numbers. A 2017 JAMA study described both survey results and urine tests of nearly 280,000 pregnant women in Northern California, where medical marijuana was legalized in 1996. The study showed that in 2009, about 4 percent of the women tested used marijuana. In 2016, about 7 percent of women did. Those California numbers may be even higher now, since recreational marijuana became legal there this year.
Some of those numbers may be due in part to women using marijuana to treat their morning sickness, a more recent study by some of the same researchers suggests. Their report, published August 20 in JAMA Internal Medicine, found that pregnant women with severe nausea and vomiting were 3.8 times more likely to use marijuana than pregnant women without morning sickness.

So some pregnant women are definitely using the drug, and exposing their fetuses to it, too. Ingredients in marijuana are known to make their way to fetuses by crossing the placenta during pregnancy (and by entering breast milk after the baby is born). But what actually happens when those marijuana compounds arrive?

That’s the question the American Academy of Pediatrics grapples with in a clinical report published in the August issue of Pediatrics. In an effort to provide guidance to caregivers and women, the AAP sums up the existing scientific literature on how marijuana affects mothers and babies.

While it seems like a bad idea to expose developing babies to marijuana, the science to back up that intuition is frustratingly slim. Some studies have turned up negative outcomes for babies, such as lower birth weight and a greater likelihood of needing the neonatal intensive care unit. And marijuana use during pregnancy has been tied to a greater risk of anemia in mothers. But other studies found no such effects.
This subject — and any topic that involves drugs and babies — is hard to study. Ethical reasons prevent scientists from assigning some pregnant women to use marijuana and others to abstain. Such randomization is a key feature of a solid study, and one that’s just not available in this case. That leaves scientists to study women who are already using marijuana while pregnant, and those women may have other characteristics that make a direct comparison difficult. That makes it harder to say whether it was marijuana, or something else, that is linked to a particular outcome.

Still, despite what the AAP calls “limited research,” there may be enough hints, from observational studies of women already using marijuana and from animal studies, to make pregnant women pause before using marijuana. Add to those red flags the fact that today’s marijuana is a lot more potent than it used to be, meaning that more of the active compound THC could reach the developing baby. And toxins such as pesticides might come along for the ride, perhaps causing other kinds of trouble.

These questions are more pressing as marijuana becomes easier to get legally, and as more pregnant women use it. Hopefully this shift will prompt scientists to figure out better ways to study the drug’s effects — or lack thereof.