The SN 10: Meet the scientists making the next big discoveries

In a recent poll, more than four-fifths of U.S. adults could not name a living scientist. Of those who could, the plurality (40 percent) named Stephen Hawking. (The next highest response was Neil deGrasse Tyson, followed by Jane Goodall.) No offense to the rightfully famous Hawking, but at Science News we would like to change these results. Why aren’t more scientists, particularly those who are young and accomplished, household names? Where, we want to know, are the Taylor Swifts of science?

You’ll find some of them below. For the second year in a row, Science News is highlighting 10 early- and mid-career scientists on their way to widespread acclaim. The SN 10: Scientists to Watch includes a laser physicist with laserlike focus, a materials scientist challenging what it means to be alive and a computational biologist willing to get personal with his microbiome, among many others who are making important advances in their chosen fields.

Though none of these scientists have recorded hit singles — at least not that our reporting uncovered — all were nominated by a Nobel laureate or recently elected member of the National Academy of Sciences. And all were age 40 or younger at the time of nomination.

These remarkable individuals have diverse personalities and talents: They are tenacious and creative, practical-minded and dreamers. They are lab animals and data heads. Some seek simplicity, others complexity. If there is one unifying trait, though, it would have to be their passion — a quality so cliché among successful scientists that it has to be true. As Marie Curie famously wrote in a letter to her sister, “Sometimes my courage fails me and I think I ought to stop working…. But I am held by a thousand bonds.” She did not know, she confessed, whether she could live without the laboratory.

Concern expands over Zika birth defects

After a year caring for patients at the heart of Brazil’s Zika epidemic, pediatric neurologist Vanessa van der Linden has seen some of the worst cases.

She was one of the first researchers to link Zika virus to microcephaly, a now well-known birth defect marked by a small, misshapen head and, sometimes, a forehead that slopes backward. Babies with the defect can have other symptoms, too: Van der Linden has seen 24-hour crying bouts, spasms, extreme irritability and difficulty swallowing.
But microcephaly is just the tip of the Zika iceberg, she said September 22 at a workshop hosted by the National Institutes of Health in North Bethesda, Md. That’s something public health officials have been warning about for months. Now, scientists have begun to describe a head-to-toe assortment of health problems linked to Zika virus infection in utero; they’re calling it congenital Zika syndrome.

Still, the full scope of the problem, including the threat of more subtle neurologic disorders such as learning disabilities or developmental delays, remains murky, says Peter Hotez, a pediatrician and microbiologist at Baylor College of Medicine in Houston.

“That’s the big unknown: There’s probably a spectrum of illness,” similar to autism, he says. And it could take years for scientists to sort it all out.

It’s a problem that Brazil is facing now, and one that Puerto Rico has just begun grappling with.

As of September 23, the U.S. territory had reported 22,358 confirmed cases of Zika infection. Of these cases, 1,871 are pregnant women. Carmen Zorrilla, an obstetrician-gynecologist at the University of Puerto Rico’s Maternal-Infant Studies Center who has examined some of these women and their babies, emphasizes the importance of following up on all babies exposed to Zika in the womb — even those without apparent birth defects.
“Even if they are born normal,” she said, “it doesn’t mean they’ll be OK.”

Insidious problems
At the workshop, Zorrilla described the case of one of the first Puerto Rican babies born to a mother diagnosed with Zika. The baby didn’t have microcephaly, but she did have another unusual problem: She couldn’t open her eyes. A bad case of conjunctivitis (pinkeye) left her needing help opening her eyelids every morning — even 27 days after birth.
Zorrilla can’t say for sure whether the problem was related to Zika, but “it really concerned me,” she said. “This is the first baby I’ve seen with conjunctivitis that lasted for so long.”

The case may be another clue that Zika’s assaults on the body are widespread. And Zorrilla can expect to see more cases soon. Ultrasound examinations of 228 women in Puerto Rico with confirmed Zika infection have spotted brain abnormalities in 13 fetuses, including one with microcephaly.

Another observation could hint at problems yet to come: Most of the Zika-exposed fetuses tended to have slightly smaller heads than average, although “still within the normal limits,” Zorrilla said. But measurements of leg bones and stomach size indicate that the rest of the body is growing normally. Implications remain unclear, but the findings — preliminary results from Alberto de la Vega, also an obstetrician-gynecologist at the University of Puerto Rico — are the latest in a litany of anomalies linked to Zika.

Long-term problems aren’t unusual in babies infected with a different kind of virus that causes microcephaly. Like Zika, cytomegalovirus can infect babies in the womb. Most CMV-infected babies don’t have any obvious symptoms, but asymptomatic kids may have problems as they grow, including intellectual disabilities, hearing loss or cerebral palsy, researchers suggested in the October Brain and Development.

Beyond microcephaly, scientists have recently described other symptoms linked to Zika infection. In some babies, for example, Zika seems to damage hearing. Of 70 Zika-exposed infants born with microcephaly, 10 percent had some hearing loss, researchers noted in a Sept. 2 report published by the U.S. Centers for Disease Control and Prevention.
Zika can leave a mark on the eyes, too. More than a third of 29 babies with microcephaly had some sort of eye oddity, including mottled pigmenting and withered tissue, researchers reported in May in JAMA Ophthalmology.

Van der Linden has also observed a link between Zika and a deformity called arthrogryposis, where a child’s joints can be stuck in contorted positions — even in babies without microcephaly. The condition might stem from problems with infected babies’ motor neurons, the nerve cells that relay messages from the brain to the muscles, van der Linden and colleagues suggested August 9 in BMJ.

She has even seen babies born with normal head circumferences who later develop microcephaly or other brain defects. One mother, she says, came in five months after giving birth because she thought her baby wasn’t developing normally. Like children with congenital Zika syndrome, the baby’s head scans revealed “the same pattern of brain damage,” van der Linden says. This pattern includes a malformed cerebral cortex, the wrinkled outer layer of the brain, and calcifications, strange lumps of calcium deposited within the tissue.

Infiltrating the brain
Scientists still don’t know exactly how Zika damages the brain, but they have some ideas.

One recent report found that the virus can infiltrate and kill both neuroepithelial stem cells, which give rise to all sorts of brain cells, and radial glial cells, which can generate newborn neurons and help guide them to their proper place in the brain.

Zika also hinders these cells’ ability to split into new cells, Yale University neuroscientist Marco Onorati and colleagues reported September 6 in Cell Reports.
Stem cells at work in the fetal brain eventually give rise to structures responsible for thought and memory and learning, raising concerns of a cascade of problems down the road. “This is a virus that blocks the development of the fetal brain,” Hotez says. “That’s about the worst thing you can possibly imagine.”

And fetuses might not be the only ones at risk, he points out. “Kids in the first years of life also have growing, developing brains,” he says. “What if they get infected with Zika?”

It’s not an easy question to answer. But another disease could offer clues.

Malaria, for example, can cause severe neurological problems. In children, a condition called cerebral malaria may be linked to mental health disorders such as attention-deficit/hyperactivity disorder, antisocial behavior and depression, researchers reported in March in Malaria Journal.

Researchers will also need to watch out for long-term troubles in Zika-exposed babies born with no obvious symptoms, says the CDC’s Sonja Rasmussen. “We don’t want to make families too scared,” she says. “But we do recognize the possibility of later-on seizures or developmental delay.”

Since most people don’t show signs of Zika infection, pinpointing the total number of pregnant women (and babies) exposed to the virus may be impossible.

In the Americas, at least, the number is probably enormous. Tens of thousands of children may eventually suffer some sort of neurologic or psychiatric illness triggered by Zika, Hotez predicted in a paper published in JAMA Pediatrics in August.

Van der Linden can’t say whether the babies she has seen have learning disabilities or psychiatric illnesses, or other more subtle cognitive problems — most of her patients are between 9 months and 1 year old.

But she plans to follow these patients, and the babies who appeared normal at birth, for years. “We need time to better understand the disease,” she says.

Hotez agrees: “It’s going to take a generation of pediatric neurologists and infectious disease experts to figure this out.”

Deciphering cell’s recycling machinery earns Nobel

Figuring out the nuts and bolts of the cell’s recycling machinery has earned the 2016 Nobel Prize in physiology or medicine. Cell biologist Yoshinori Ohsumi of the Tokyo Institute of Technology has received the prize for his work on autophagy, a method for breaking down and recycling large pieces of cellular junk, such as clusters of damaged proteins or worn-out organelles.

Keeping this recycling machinery in good working condition is crucial for cells’ health (SN: 3/26/11, p. 18). Not enough recycling can cause cellular trash to build up and lead to neurological diseases such as Alzheimer’s and Parkinson’s. Too much recycling, on the other hand, has been linked to cancer.
“It’s so exciting that Ohsumi has received the Nobel Prize, which he no question deserved,” says biologist Jennifer Lippincott-Schwartz of Howard Hughes Medical Institute’s Janelia Research Campus in Ashburn, Va. “He set the framework for an entire new field in cell biology.”

Ohsumi‘s discoveries helped reveal the mechanism and significance of a fundamental physiological process, biologist Maria Masucci of the Karolinska Institute in Sweden said in a news briefing October 3. “There is growing hope that this knowledge will lead to the development of new strategies for the treatment of many human diseases.”

Scientists got their first glimpse of autophagy in the 1960s, not long after the discovery of the lysosome, a pouch within cells that acts as a garbage disposal, grinding fats and proteins and sugars into their basic building blocks. (That discovery won Belgian scientist Christian de Duve a share of the Nobel Prize in 1974.) Researchers had observed lysosomes stuffed with big chunks of cellular material — like the bulk waste of the cellular world — as well as another, mysterious pouch that carried the waste to the lysosome.

Somehow, the cell had devised a way to consume large parts of itself. De Duve dubbed the process autophagy, from the Greek words for “self” and “to eat.” But over the next 30 years, little more became known about the process.
“The machinery was unknown, and how the system was working was unknown, and whether or not it was involved in disease was also unknown,” said physiologist Juleen Zierath, also of the Karolinska Institute, in an interview after the prize’s announcement.

That all changed in the 1990s when Ohsumi decided to study autophagy in a single-celled organism called baker’s yeast, microbes known for making bread rise. The process was tricky to catch in action, partly because it happened so fast. So Ohsumi bred special strains of yeast that couldn’t break down proteins in their cellular garbage disposals (called vacuoles in yeast).

“He reasoned that if he could stop the degradation process, he could see an accumulation of the autophagy machinery in these cells,” Zierath said.

And that’s just what Ohsumi saw. When he starved the yeast cells, the “self-eating” machinery kicked into gear (presumably to scrounge up food for the cells). But because the garbage disposals were defective, the machinery piled up in the vacuoles, which swelled like balloons stuffed with sand. Ohsumi could see the bulging, packed bags clearly under a light microscope. He published the work in a 1992 paper in the Journal of Cell Biology.
Finding the autophagy machinery let Ohsumi study it in detail. A year later, he discovered as many as 15 genes needed for the machinery to work. In the following years, Ohsumi and other scientists examined the proteins encoded by these genes and began to figure out how the components of the “bulk waste” bag, or autophagosome, came together, and then fused with the lysosome.

The work revealed something new about the cell’s garbage centers, Zierath said. “Before Ohsumi came on the scene, people understood that the waste dump was in the cell,” she said. “But what he showed was that it wasn’t a waste dump. It was a recycling plant.”

Later, Ohsumi and his colleagues studied autophagy in mammalian cells and realized that the process played a key maintenance role in all kinds of cells, breaking down materials for reuse. Ohsumi “found a pathway that has its counterparts in all cells that have a nucleus,” says 2013 Nobel laureate Randy Schekman, a cell biologist at the University of California, Berkeley. “Virtually every corner of the cell is touched by the autophagic process.”

Since Ohsumi’s discoveries, research on autophagy has exploded, says Lippincott-Schwartz. “It’s an amazing system that every year becomes more and more fascinating.”

Ohsumi, 71, remains an active researcher today. He received the call from the Nobel committee at his lab in Japan. The prize includes an award of 8 million Swedish kronor (equivalent to about $934,000). About his work, he said: “It was lucky. Yeast was a very good system, and autophagy was a very good topic.”

Still, he added in an interview with a Nobel representative, “we have so many questions. Even now we have more questions than when I started.”

Saturn’s moon Dione might harbor an underground ocean

A satellite of Saturn joins the club of moons with possible oceans. A subsurface sea of water might hide beneath the icy crust of Dione, one of Saturn’s moons, researchers report online October 9 in Geophysical Research Letters. That puts Dione in good company alongside Enceladus (another moon of Saturn) and several moons of Jupiter, as well as possibly Pluto (SN Online: 9/23/16).

Dione’s ocean is about 100 kilometers below the surface and roughly 65 kilometers deep, Mikael Beuthe, a planetary scientist at the Royal Observatory of Belgium in Brussels, and colleagues report. They inferred the ocean’s presence from measurements of Dione’s gravity made by the Cassini spacecraft.

Baby-led weaning is safe, if done right

When babies are ready for solid foods, the meal usually arrives on a spoon. Parents scoop up pureed carrots, liquefied banana or soupy rice cereal and deliver it straight to their baby’s mouth (or forehead). But a different way of introducing solids is gaining ground. Called baby-led weaning, the approach is based on letting the baby feed herself whole foods such as a soft pear or a spear of cooked broccoli — no spoon required.

Advocates say that by having control over what goes in their mouths, babies learn to regulate their food intake, refine motor skills and perhaps even become more adventurous eaters. But critics fret that inexperienced eaters may be more likely to choke on solid foods that they feed themselves. A new study of about 200 Australian babies has some reassuring news: Provided that certain risky foods were avoided, babies who fed themselves solid foods were no more likely to choke than spoon-fed babies.

Half of the babies started solid food the traditional way, with parents spoon-feeding them purees and other mushy foods. The other half were given solid foods on their trays and encouraged to feed themselves. Parents were told that babies ought to be sitting up and in the presence of a caregiver while eating. And parents also received a list of risky foods to avoid: hard crackers, diced or hard meat, raw vegetables and popcorn made the list. (A general rule of thumb for checking whether the food is safe: If you can squish the food against the roof of your mouth, then it’s probably OK for your baby to try.)

Spoon-fed babies choked just as much as babies who fed themselves, the researchers report in the September Pediatrics. At 6 months of age, about 22 percent of spoon-fed babies had choked at least once. In the baby-led weaning group, about 18 percent of babies had choked at least once. Choking rates between the two groups were on par as the babies grew older.

There’s an important distinction here between gagging and true choking. Gagging is common among babies as their mouths learn to handle new textures and flavors. The throat slams shut and the mouth tries to get the offending food out. A gagging baby may have watery eyes, push his tongue out of his mouth and make retching movements. He may even puke. This can be hard for parents to watch, but gagging isn’t dangerous.

True choking is. This is when the airway becomes partially or fully blocked. The baby may cough or sputter in an attempt to dislodge the food. He may make a raspy, squeaky whisper as he tries to communicate distress. Or he may go silent. It’s always good to be up on infant CPR, particularly if you’ve got a new eater.

The babies who fed themselves seemed to quickly hone their skills. Initially, self-feeding babies gagged more often than spoon-fed babies at 6 months of age. But by 8 months old, self-feeders had become experts, gagging less than spoon-fed babies.
Although the news seems good for parents who want to try baby-led weaning, the research also turned up something concerning: Lots of babies were given risky foods, regardless of feeding style. At seven months of age, just over half of babies were given something from the no-feed list. By 12 months, almost all the babies had been given riskier foods that can lead to choking. Hard crackers, meat and whole grapes topped the list.

The results suggest that whether you feed your baby or you let your baby feed herself, it’s still important to pay attention to the type of food that’s going into her cute little mouth.