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Frog brains get busy long before they’re fully formed. Just a day after fertilization, embryonic brains begin sending signals to far-off places in the body, helping oversee the layout of complex patterns of muscles and nerve fibers. And when the brain is missing, bodily chaos ensues, researchers report online September 25 in Nature Communications.

The results, from brainless embryos and tadpoles, broaden scientists’ understanding of the types of signals involved in making sure bodies develop correctly, says developmental biologist Catherine McCusker of the University of Massachusetts Boston. Scientists are familiar with short-range signals among nearby cells that help pattern bodies. But because these newly described missives travel all the way from the brain to the far reaches of the body, they are “the first example of really long-range signals,” she says.
Celia Herrera-Rincon of Tufts University in Medford, Mass., and colleagues came up with a simple approach to tease out the brain’s influence on the growing body. Just one day after fertilization, the scientists lopped off the still-forming brains of African clawed frog embryos. These embryos survive to become tadpoles even without brains, a quirk of biology that allowed the researchers to see whether the brain is required for the body’s development.
The answer was a definite — and surprising — yes, Herrera-Rincon says. Long before the brain is mature, it’s already organizing and guiding organ behavior, she says. Brainless tadpoles had bungled patterns of muscles. Normally, muscle fibers form a stacked chevron pattern. But in tadpoles lacking a brain, this pattern didn’t form correctly. “The borders between segments are all wonky,” says study coauthor Michael Levin, also of Tufts University. “They can’t keep a straight line.”
Nerve fibers that crisscross tadpoles’ bodies also grew in an abnormal pattern. Levin and colleagues noticed extra nerve fibers snaking across the brainless tadpoles in a chaotic pattern, “a nerve network that shouldn’t be there,” he says.

Muscle and nerve abnormalities are the most obvious differences. But brainless tadpoles probably have more subtle defects in other parts of their bodies, such as the heart. The search for those defects is the subject of ongoing experiments, Levin says.
In addition to keeping patterns on point, the young frog brain may protect its body from chemical assaults. A molecule that binds to certain proteins on cells in the body had no effect on normal embryos. But when given to brainless embryos, the same molecule caused their spinal cords and tails to grow crooked. These results suggest that early in development, brains keep embryos safe from agents that would otherwise cause harm.

“The brain is instructing cells that are really a long way away from it,” Levin says. While the precise identities of these long-range signals aren’t known, the researchers have some ideas. When brainless embryos were dosed with a drug that targets cells that typically respond to the chemical messenger acetylcholine, the muscle pattern improved. Similarly, the addition of a protein called HCN2 that can tweak the activity of cells also seemed to improve muscle development. More work is needed before scientists know whether these interventions are actually mimicking messaging from the early brain, and if so, how.

Frog development isn’t the same as mammalian development, but frog development “is pretty applicable to human biology,” McCusker says. In fundamental ways, humans and frogs are built from the same molecular toolbox, she says. So the results hint that a growing human brain might also interact similarly with a growing human body.

As far as last meals go, squid isn’t a bad choice. Cephalopod remains appear to dominate the stomach contents of a newly analyzed ichthyosaur fossil from nearly 200 million years ago.

The ancient marine reptiles once roamed Jurassic seas and commonly pop up in England’s fossil-rich coast near Lyme Regis. But a lot of ichthyosaur museum specimens lack records of where they came from, making their age difficult to place.

Dean Lomax of the University of Manchester and his colleagues reexamined one such fossil. Based on its skull, they identified the creature as a newborn Ichthyosaurus communis. Microfossils of shrimp and amoeba species around the ichthyosaur put the specimen at 199 million to 196 million years old, the researchers estimate.

Tiny hook structures stand out in the newborn’s ribs — most likely the remnants of prehistoric black squid arms. Another baby ichthyosaur fossil that lived more recently had a stomach full of fish scales. So the new find suggests a shift in the menu for young ichthyosaurs at some point in their evolutionary history, the researchers write October 3 in Historical Biology.

The only lemurs so dependent on bamboo that they gnaw on hardened, nutrient-poor stems during the dry season might dwindle away as those seasons grow longer.

Reconstructing the history of the greater bamboo lemur (Prolemur simus) in Madagascar suggests that drier areas over thousands of years already have lost their populations. As the region dries further due to climate change and the bad-bamboo months in the last holdouts lengthen, remaining populations of these critically endangered lemurs might go hungry and fade away too, an international research team warns online October 26 in Current Biology.

Other animals, even another lemur species, will eat lots of bamboo shoots and leaves. But the greater bamboo lemur is the only mammal besides the giant panda that sticks with bamboo during the dry season. That’s when the plants stop sprouting and offer only culm, the tough, old, yellowing stems poor in nutrients. Culm hasn’t reached the hard stage of bamboo that’s used as a building material. “Nobody wants to eat that,” says study coauthor Alistair Evans, an evolutionary morphologist at Monash University in Melbourne, Australia.

This lemur species with its extreme diet had already been feared extinct once, around the middle of the last century, but relic populations turned up. Current survivors remain more toward the eastern part of the island, where dry seasons are apparently survivable, at least for now.

In a big step toward catching up with the rest of the world, the United States cleared the way for using mosquitoes as a commercial pest control for the first time.

The U.S. Environmental Protection Agency has approved using a strain of male Asian tiger mosquitoes (Aedes albopictus) as a biopesticide in the District of Columbia and 20 states, including California and New York. Kentucky-based MosquitoMate was granted the right to sell these mosquitoes, called ZAP Males, for the next five years, the agency announced November 7.
These male mosquitoes are not genetically modified. Instead they carry a strain of Wolbachia bacteria that turns them into saboteur dads. When they mate with wild females not carrying the strain, the offspring will die and the population should dwindle. Males don’t bite, so releasing them should not add extra vexation.

Releases of Wolbachia-bearing mosquitoes for pest control already go on in other countries, such as Brazil, although with a different bacterial strain and a different strategy.

This same company has also been testing the effectiveness of a different mosquito species, Aedes aegypti, also carrying bad-dad Wolbachia, near Key West, Fla. (These mosquitoes are not commercially available.) The tests “ended a bit early due to [Hurricane] Irma,” says Stephen Dobson of MosquitoMate, “but we think that we have some good data despite this complication.”

The human brain is teeming with diversity. By plucking out delicate, live tissue during neurosurgery and then studying the resident cells, researchers have revealed a partial cast of neural characters that give rise to our thoughts, dreams and memories.

So far, researchers with the Allen Institute for Brain Science in Seattle have described the intricate shapes and electrical properties of about 100 nerve cells, or neurons, taken from the brains of 36 patients as they underwent surgery for conditions such as brain tumors or epilepsy. To reach the right spot, surgeons had to remove a small hunk of brain tissue, which is usually discarded as medical waste. In this case, the brain tissue was promptly packed up and sent — alive — to the researchers.
Once there, the human tissue was kept on life support for several days as researchers analyzed the cells’ shape and function. Some neurons underwent detailed microscopy, which revealed intricate branching structures and a wide array of shapes. The cells also underwent tiny zaps of electricity, which allowed researchers to see how the neurons might have communicated with other nerve cells in the brain. The Allen Institute released the first publicly available database of these neurons on October 25.

A neuron called a pyramidal cell, for instance, has a bushy branch of dendrites (orange in 3-D computer reconstruction, above) reaching up from its cell body (white circle). Those dendrites collect signals from other neural neighbors. Other dendrites (red) branch out below. The cell’s axon (blue) sends signals to other cells that spur them to action.
Like the chandelier cell, a Martinotti cell (below) quiets other cells with messages coming from its tangled, tall axon, which spans several layers of the brain’s cortex — the wrinkly, outer layer that’s involved in higher-level thought. And in a basket cell (above), axon branches, which allow the nerve cell to send messages to other neurons, cluster densely around the cell body.
Because the neurons play different roles in the brain, the new collection could help researchers figure out the details of those diverse jobs. Similar data exist for cells taken from the brains of other animals, such as mice, but until now, data on live cells from people have been scarce.

“These neurons are amazingly beautiful,” says Ed Lein, a neuroscientist at the Allen Institute who works on the project. “They look like trees. They’re much more complex than similar cells in a mouse.”

BOSTON — Long before anyone opened a bank account or rented a safe deposit box, wealth protection demanded a bit of guile and a broken beer jug. A 3,100-year-old jewelry stash was discovered in just such a vessel, unearthed from an ancient settlement in Israel called Megiddo in 2010. Now the find is providing clues to how affluent folk hoarded their valuables at a time when fortunes rested on fancy metalwork, not money.

At the fortress city of Megiddo, a high-ranking Canaanite family stashed jewelry in a beer jug and hid it in a courtyard’s corner under a bowl, possibly under a veil of cloth, Eran Arie of the Israel Museum in Jerusalem, said November 17 at the annual meeting of the American Schools of Oriental Research.
The hoard’s owners removed the jug’s neck and inserted a bundle of 35 silver items, including earrings and a bracelet, which were wrapped in two linen cloths. Other valuables were then added to the jug, including around 1,300 beads of silver and electrum — an alloy of gold and silver — that had probably been threaded into an elaborate necklace. There were 10 additional pieces of electrum jewelry, including a pair of basket-shaped earrings, each displaying a carved, long-legged bird.
A Canaanite city palace stood only about 30 meters from the Iron Age building that housed the courtyard, Arie said. Due to the lesser building’s strategic location, its inhabitants must have held key government positions, he proposed. “For the family that lived there, the hoard represented the lion’s share of their wealth.” Those family members presumably fled around the time the structure that held the jewelry hoard was destroyed in a catastrophic event, possibly a battle.
The Megiddo hoard was hidden but not buried, giving its owners quick access to their valuables. But no one ever retrieved the treasure. “We will never know why no one returned to claim this hoard,” Arie said.

The weird glowing blob of gas known as Hanny’s Voorwerp was a 10-year-old mystery. Now, Lia Sartori of ETH Zurich and colleagues have come to a two-pronged solution.

Hanny van Arkel, then a teacher in the Netherlands, discovered the strange bluish-green voorwerp, Dutch for “object,” in 2008 as she was categorizing pictures of galaxies as part of the Galaxy Zoo citizen science project.

Further observations showed that the voorwerp was a glowing cloud of gas that stretched some 100,000 light-years from the core of a massive nearby galaxy called IC 2497. The glow came from radiation emitted by an actively feeding black hole in the galaxy.
To excite the voorwerp’s glow, the black hole and its surrounding accretion disk, the active galactic nucleus, or AGN, should have had the brightness of about 2.5 trillion suns; its radio emission, however, suggested the AGN emitted the equivalent of a relatively paltry 25,000 suns. Either the AGN was obscured by dust, or the black hole slowed its eating around 100,000 years ago, causing its brightness to plunge.

Sartori and colleagues made the first direct measurement of the AGN’s intrinsic brightness using NASA’s NuSTAR telescope, which observed IC 2497 in high-energy X-rays that cut through the dust.

They found that the AGN is obscured by dust and it is dimmer than expected; the feeding has slowed way down. The team reported on arXiv.org on November 20 that IC 2497’s heart is as bright as 50 billion to 100 billion suns, meaning it dropped in brightness by a factor of 50 in the past 100,000 years — a less dramatic drop than previously thought.
“Both hypotheses that we thought before are true,” Sartori says.

Sartori plans to analyze NuSTAR observations of other voorwerpjes to see if their galaxies’ black holes are also in the process of shutting down — or even booting up.

“If you look at these clouds, you get information on how the black hole was in the past,” she says. “So we have a way to study how the activity of supermassive black holes varies on superhuman time scales.”

Editor’s note: This story was updated December 5, 2017, to clarify that the brightness measured by the researchers came from the accretion disk around an actively eating black hole, not the black hole itself.

When escaping from humans, narwhals don’t just freeze or flee. They do both.

These deep-diving marine mammals have similar physiological responses to those of an animal frozen in fear: Their heart rate, breathing and metabolism slow, mimicking a “deer in the headlights” reaction. But narwhals (Monodon monoceros) take this freeze response to extremes. The animals decrease their heart rate to as slow as three beats per minute for more than 10 minutes, while pumping their tails as much as 25 strokes per minute during an escape dive, an international team of researchers reports in the Dec. 8 Science.
“That was astounding to us because there are other marine mammals that can have heart rates that low but not typically for that long a period of time, and especially not while they’re swimming as hard as they can,” says Terrie Williams, a biologist at the University of California, Santa Cruz. So far, this costly escape has been observed only after a prolonged interaction with humans.

Usually, narwhals will escape natural predators such as killer whales by stealthily slipping under ice sheets or huddling in spots too shallow for their pursuers, Williams says. But interactions with humans — something that will happen increasingly as melting sea ice opens up the Arctic — may be changing that calculus.
“When narwhals detect humans, they often dive quickly and disappear from sight,” says Kristin Laidre, an ecologist at the University of Washington in Seattle who studies marine mammals in the Arctic.
Williams and her colleagues partnered with indigenous hunters in East Greenland to capture narwhals in nets. Then, the researchers stuck monitoring equipment to the narwhals’ backs with suction cups and released the creatures. The team tracked the tail stroke rate and cardiovascular response of the narwhals after their release, and determined how much energy the animals used during their deep escape dives.

During normal dives, narwhals reduce their heart rate to about 10 to 20 beats per minute to conserve oxygen while spending prolonged time underwater. These regular deep dives to forage for food don’t require rigorous exercise. But during escape dives after being entangled in a net for an hour or longer, “the heart rates were going down to levels of three and four beats per minute, and being maintained at that level for 10 minutes at a time,” Williams says.

The narwhals were observed making multiple dives to depths of 45 to 473 meters in the hours following escape. When fleeing, the tusked animals expended about three to six times as much energy as they normally burn while resting. The authors calculated that the frantic getaway, combined with what they called “cardiac freeze,” severely and rapidly depletes the narwhals’ available oxygen in their lungs, blood and muscles — using 97 percent of the creatures’ oxygen stores compared with 52 percent on normal dives of similar depth and duration.

“There is a concern from our group that this is just pushing the biology of these animals beyond what they can do,” Williams says. As human activity increases in the Arctic, there may be more chance of inciting this potentially harmful escape response in narwhals.

The creatures may also become more vulnerable to other human-caused disturbances, such as seismic exploration, hunting and noise from large vessels and fishing boats. The researchers plan to investigate whether these activities cause the same flee-and-freeze reaction, and whether this extreme response affects narwhals’ long-term health.

This study “provides a new physiological angle on the vulnerability of narwhals to anthropogenic disturbance, which is likely to increase in the Arctic with sea ice loss,” Laidre says. Better understanding the human impacts on narwhals is essential for conservation of this species, she adds.

Discoveries of planets around distant stars have become almost routine. But finding seven exoplanets in one go is something special. In February, a team of planet seekers announced that a small, cool star some 39 light-years away, TRAPPIST-1, hosts the most Earth-sized exoplanets yet found in one place: seven roughly Earth-sized worlds, at least three of which might host liquid water (SN: 3/18/17, p. 6).

These worlds instantly became top priorities in the search for life outside the solar system. “TRAPPIST-1 is on everybody’s wish list,” says exoplanet astronomer Lisa Kaltenegger of Cornell University. But the planets and their dim star have also stoked a raging debate about what makes a planet habitable in the first place.
Astrophysicist Michaël Gillon of the University of Liège in Belgium and colleagues found the family of worlds orbiting the ultracool dwarf star, dubbed TRAPPIST-1 for the small telescope in Chile used to discover its planets.

“I don’t think the cachet of that system is going away anytime soon,” says exoplanet expert Sara Seager of MIT.

The TRAPPIST telescope team first announced in May 2016 that the star had three temperate, rocky planets. Staring at the system with the Spitzer Space Telescope for almost three weeks straight revealed that the third planet was actually four more — all Earth-sized, and three of them are in the star’s habitable zone, the region where temperatures are right for liquid water on a planet’s surface. A seventh planet was caught crossing the star as well, though follow-up observations showed it is too cold for life as we know it (SN: 6/24/17, p. 18).
Similar but different
Planets orbiting the star TRAPPIST-1 are a lot alike in some ways and distinct in others. The slideshow below shows each planet’s specs, including how long it takes to orbit the dwarf star, distance from the star (in astronomical units), and radius and mass relative to Earth.
The number of worlds alone makes the TRAPPIST-1 system a good spot to look for life. An alien observing our solar system would think Venus, Earth and Mars all fall in the habitable zone. But only one is inhabited. The fact that TRAPPIST-1 has so many options increases the odds that the system hosts life, Seager says.

As an ultracool dwarf, TRAPPIST-1 rides the edge of what counts as a star. Such stars burn through their nuclear fuel so slowly that they can live for many billions of years, which gives any life on their planets a long time to grow and evolve. This star’s habitable zone is also incredibly close in, offering astronomers many chances to observe the planets orbiting their star.

The three planets in the habitable zone cross in front of the star every 6.10, 9.21 and 12.35 days. If two or more turn out to be habitable, then they could share life among them, either by tossing meteorites back and forth or — in the case of spacefaring civilizations — by deliberate space travel.
Future space-based observatories will be able to see starlight filtering through the planets’ atmospheres, if the planets have atmospheres. Gillon and colleagues are looking for signs of escaping hydrogen, a signal that an atmosphere might be there. “We’re already preparing,” he says.

But ultracool dwarfs are also ill-tempered. They tend to emit frequent, powerful stellar flares, which could rip away a planet’s atmosphere, threatening any potential for life. The planet-hunting Kepler space telescope recently watched TRAPPIST-1 for 80 days and saw it flare 42 times. One of those flares was as strong as Earth’s 1859 Carrington Event, among the strongest geomagnetic storms ever observed.

But there are other promising systems. Recently, a similar star, Ross 128, only 11 light-years from Earth and much calmer than TRAPPIST-1, was found to have an Earth-mass planet, making it a better place to look for life, researchers reported in November in Astronomy & Astrophysics.

Whether such stars are good or bad for life is an old and open question (SN: 6/24/17, p. 18). TRAPPIST-1’s advantage is in its numbers. “We can check it, not just with one planet but with many planets,” Kaltenegger says. “You have hotter than Earth, like Earth and colder than Earth. If you wanted Goldilocks, this is the ideal scenario.”

TRAPPIST-1 is just an opening act. A bigger, more sensitive observatory called SPECULOOS is expected to be fully operational in the Chilean desert in early 2019, Gillon says. SPECULOOS will seek planets around 1,000 ultracool dwarf stars over 10 years. “We are at the edge of maybe detecting life around another star,” he says. “It’s really a possibility.”

The holiday onslaught is upon us. For some families with children, the crush of holiday gifts — while wonderful and thoughtful in many ways — can become nearly unmanageable, cluttering both rooms and minds.

This year, I’m striving for simplicity as I pick a few key presents for my girls. I will probably fail. But it’s a good goal, and one that has some new science to back it. Toddlers play longer and more creatively with toys when there are fewer toys around, researchers report November 27 in Infant Behavior and Development.
Researchers led by occupational therapist Alexia Metz at the University of Toledo in Ohio were curious about whether the number of toys would affect how the children played, including how many toys they played with and how long they spent with each toy. The researchers also wondered about children’s creativity, such as the ability to imagine a bucket as a drum or a hat.

In the experiment, 36 children ages 18 to 30 months visited a laboratory playroom twice while cameras caught how they played. On one visit, the room held four toys. On the other visit, the room held 16 toys.

When in the playroom with 16 toys, children played with more toys and spent less time with each one over a 15-minute session, the researchers found. When the same kids were in a room with four toys, they stuck with each toy longer, exploring other toys less over the 15 minutes.

What’s more, the quality of the children’s play seemed to be better when fewer toys were available. The researchers noted more creative uses of the toys when only four were present versus 16.
Metz and colleagues noticed that initial attempts to play with a toy were often superficial and simple. But if a kid’s interest stuck, those early pokes and bangs turned into more sophisticated manners of playing. This type of sustained engagement might help children learn to focus their attention, a skill Metz likened to a “muscle that they have to exercise.” This attentional workout might not happen if kids are perpetually exposed to lots of distracting toys.

The toys used in the study didn’t include electronic devices such as tablets. Only one of the four toys and only four of the 16 toys used batteries. Noisy toys may have their own troubles. They can cut down on parent-child conversations, scientists have found. It’s possible that electronics such as televisions or tablets would have even greater allure than other toys.

Nor do the researchers know what would happen if the study had been done in kids’ houses and with their own toys. It’s possible that the novelty of the new place and the new toys influenced the toddlers’ behavior. (As everyone knows, the toys at a friend’s house are way better than the toys a kid has at home, even when they are literally the exact same toy.)

The results don’t pinpoint the optimal number of toys for optimal child development, Metz says. “It’s a little preliminary to say this is good and that is bad,” she says. But she points out that many kids are not in danger of having too few toys. In fact, the average number of toys the kids in the study had was 87. Five families didn’t even provide toy counts, instead answering “a lot.”

“Because of the sheer abundance of toys, there’s no harm in bringing out a few at a time,” Metz says.

That’s an idea that I’ve seen floating around, and I like it. I’ve already started packing some of my kids’ toys out of sight, with the idea to switch the selection every so often (or more likely, never). Another recommendation I’ve seen is to immediately hide away some of the new presents, which aren’t likely to be missed in the holiday pandemonium, and break them out months later when the kids need a thrill.