In mice, the fight-or-flight response overactivates the cells, causing a drop in their numbers, which leads to loss of hair color.


Stress definitely does turn hair gray—in mice, at least.

Researchers have found that stress triggers the fight-or-flight response, which damages the cells that ultimately give skin and hair its color and leads to the cells’ depletion. In experiments, dark-furred mice that were stressed turned white in just days, the team reported yesterday (January 22) in Nature.

Folklore has long suggested that stress could strip the color from even the richest reds, blondes, and browns, but how it happens has been a mystery. “It was satisfying to question a popular assumption . . . [and] to identify the mechanisms that now open up new areas of work,” Ya-Chieh Hsu, a stem cell biologist at Harvard University and a coauthor of the study, tells Science News.

In their study, Hsu and her colleagues injected a compound related to capsaicin—an ingredient in chili peppers that gives them their heat—into mice to stress the animals. Five days later, the mice’s fur lost its color. The team thought the immune system might be killing the pigment-producing cells, but experiments showed that wasn’t happening. The stress hormone cortisol wasn’t involved in the loss of color either.

Instead, the team found, the color loss was related to the way stress affects the mice’s sympathetic nervous system, which is responsible for the fight-or-flight response. Stress triggered the fight-or-flight response, which caused a release of norepinephrine, a neurotransmitter that aids muscle contraction, including contraction of the heart. Norepinephrine, the researchers show, also caused stem cells in hair follicles to rapidly convert to pigment-producing cells called melanocytes, which regularly die. In the stressed mice, all of the stem cells differentiated into melanocytes, depleting the pool of stem cells completely within five days. That ultimately left no melanocytes to give the mice’s fur its color. The team tested the mechanism in cultures of human melanocyte stem cells and found a similar result.

“I was amazed by how dramatic this change is,” Mayumi Ito, a biologist at the New York University School of Medicine who was not involved in the study, tells The New York Times. She studies graying of aging mice. In her animals the color change is gradual because the depletion of melanocytes is much slower.

“Melanocyte stem cells are also lost during aging,” Hsu tells Reuters. “An interesting hypothesis could be that stress is an accelerated aging process. But we don’t know if that is true yet. We are interested in finding out the link.”


Plants pollinated by nectar-drinking bats often have flowers that reflect ultrasonic waves, making it easier for the animals to locate flowers through echolocation. But one cactus does the opposite—it absorbs more ultrasound in the area surrounding its flowers, making them stand out against a “quieter” background, according to a preprint published on bioRxiv last month.

Espostoa frutescens is a type of column-shaped cactus found only in the Ecuadorian Andes mountains. It has small flowers on its side that open at night, attracting bats as they fly from flower to flower in search of nectar. One of its main pollinators is Geoffroy’s tailless bat (Anoura geoffroyi).

“Bats are really good pollinators,” Ralph Simon, a postdoc in Wouter Halfwerk’s lab at Vrije Universiteit Amsterdam and the lead author of the preprint, tells The Scientist. “They carry a lot of pollen in their fur, and they have a huge home range so they can transport pollen from plants that grow far apart. For plants with a patchy distribution pattern like this cactus, it’s especially beneficial to rely on bats for pollination,” he says.

For bats to find the flowers at night, they use echolocation, emitting ultrasonic calls too high for humans to hear that bounce off objects and allow the bats to form a mental map of their surroundings. Some plants have evolved techniques that take advantage of this sonar system and allow bats to better detect flowers, such as making their petals more concave, forming a more reflective surface that can bounce more echolocation back to the bat. But E. frutescens takes a different approach.

Each of E. frutescens’s flowers are surrounded by an area of wooly hairs called the cephalium. Simon and colleagues knew from past measurements that the hairs were sound-absorbent, and were interested in seeing whether this part of the cactus could be involved in helping bats find the flowers. They attached a microphone and speaker to a device resembling the shape and size of a bat head in order to mimic a bat, and played prerecorded echolocation calls to the cacti and measured how much sound was reflected back to the bat replica.

The team found that the hairy cephalium absorbed ultrasound, and that the greatest absorption occurred above 90 kHz, in the range of the frequency of Geoffroy’s tailless bat’s echolocation call. The sound that bounced back to the microphone from the cephalium area was about 14 decibels quieter than the sound that bounced off the non-hairy part of the cacti.

It’s a “totally different mechanism” than the reflection method other cacti use, says Simon. “Instead of making the flowers conspicuous, it dampens the background. The background absorbs the ultrasound, and the flowers show up in [the middle of] this absorbent fur.”

This mechanism makes sense from a communication standpoint, writes May Dixon, a graduate student studying bat behavior in Mike Ryan’s lab at the University of Texas at Austin who was not involved with the study, in an email to The Scientist. “If you are trying to send a message, you have to think not only about the message itself but also the context. For example, if you are calling someone, you should be loud enough for them to hear, sure, but you should also call from a quiet place,” she says.

“There is something wonderful about the ways that plants have found to communicate with animals through evolution,” Dixon notes. “A cactus has no sense of what it is to be a bat—it can’t see, smell, or echolocate—but here it is, sending a bat a message in a language that a bat can understand.”

The cephalium appears to have originally evolved to protect flowers from environmental stressors such as UV rays, drying out, getting too cold, or being eaten, but “during evolution, it co-opted another function, and it functions as a sound absorbing structure as well,” says Simon. The evolution of this mechanism benefits both cactus and bat. “From the bat point of view, with this mechanism, they save time. And for them, it’s important to save time, because they have to visit several hundred flowers each night to get enough energy,” he says.

The current study did not look at whether sites on the plants with the highest sound absorption in the bats’ echolocation range “indeed resulted in the highest detection and visitation rates by bats,” says Jan Komdeur, an evolutionary ecologist at University of Groningen in the Netherlands who did not participate in the research, in an email to The Scientist. In the future, researchers could investigate how often real-life bats approach hairy versus experimentally manipulated hairless flowers, he suggests.

Jorge Schondube, an ecologist at the Universidad Nacional Autónoma de México who was not involved with the study, agrees that research on real-life bats is needed. “The pattern’s very clear, but now [researchers] need to show how the mechanism is actually changing the behavior of the bats,” he says.

Still, he’s impressed by the findings so far. “Nature is very creative. And by being creative, it allows the origin of completely new and unimaginable things. It’s really surprising that something like this can happen, and the paper shows it really, really beautifully. . . . What we’re seeing here is something that has not been seen before in terms of sound.”–enticing-bats-to-flowers-66981?utm_campaign=TS_DAILY%20NEWSLETTER_2020&utm_source=hs_email&utm_medium=email&utm_content=82166272&_hsenc=p2ANqtz-9in3Tqjl731fVW0JE_k3Ht2NOEvCOnql7E5ADhmEp4j43Rrs5Q6gxTipSPvHXAs-8C6MvOvVFdBpktnFeyya1pvZPF2A&_hsmi=82166272

Pet scans comparing brains with Alzheimer’s with healthy brains. The researchers used PET scans to study the brains of 32 people with early Alzheimer’s. Photograph: Jonathan Selig/Getty Images
Research suggests tangles of tau could be used to predict how much shrinkage will occur and where

Tangles of a protein found inside the brain cells of people with Alzheimer’s disease can be used to predict future brain shrinkage, research suggests.

In healthy people, a protein called tau is important in supporting the internal structure of brain cells. However, in those with Alzheimer’s, chemical changes take place that cause the protein to form tangles that disrupt the cells. Such tangles have previously been linked to a loss of brain cells.

Now scientists have used imaging techniques to track the extent of tau tangles in the brains of those with early signs of Alzheimer’s, revealing that levels of the protein predict not only how much brain shrinkage will subsequently occur, but where.

“Our study supports the notion that tau pathology accumulates upstream of brain tissue loss and clinical symptoms,” said Prof Gil Rabinovici, a co-author of the research from the University of California, San Francisco.

A number of drugs targeting tau tangles are currently in clinical trials, including some that aim to interfere with the production of tau in the brain or its spread between cells.

Dr Renaud La Joie, another author of the research, said the findings suggested the imaging technique could prove valuable both in choosing which patients to enrol to test such drugs and in monitoring whether the drugs work.

Dr Laura Phipps, of Alzheimer’s Research UK, said: “The ability to track tau in the brain will be critical for testing treatments designed to prevent the protein causing damage, and the scans used in this study could be an important tool for future clinical trials.”

Writing in the journal Science Translational Medicine, La Joie and colleagues report how they used an imaging technique called positron emission tomography (Pet) to study the brains of 32 people aged between 49 and 83 who were in the early stages of showing Alzheimer’s symptoms.

Pet imaging involves injecting patients with a substance that contains a radioactive atom. The area in which the substance clusters shows up in subsequent scans.

The scientists used one substance that attaches to plaques of a protein in the brain known as beta amyloid, a hallmark of Alzheimer’s disease, and another recently developed substance that attaches to tau tangles.

They took a Pet scan at the start of the study, as well as an MRI, which reveals the structure of the brain. A second MRI was taken 15 months later to track brain atrophy.

The results reveal the level and location of tau tangles shown by the Pet scan at the outset were closely linked to shrinkage of grey matter in the brain, both in terms of the degree of shrinkage and its location. Such patterns explained about 40% of the variation in shrinkage. By contrast, there was little sign of a link between brain shrinkage and the extent of beta amyloid shown by Pet scan.

The findings held even when the thickness of the brain’s grey matter at the start of the study was taken into account, and when the age of participants was considered.

Although previous research has suggested brain atrophy shows a stronger link to tau tangles than beta amyloid, the team say the findings were still a surprise. “We were amazed by how well tau predicted not only the degree of atrophy overall, but the precise location of atrophy in individual patients,” said La Joie.

But, he added, the lack of a link to signs of beta amyloid does not mean those plaques are not harmful. “It is extremely rare to see significant amounts of tau tangles across the brain in patients with no amyloid: for some reason, amyloid seems almost necessary for tau to build up in the cortex,” said La Joie.

The study has limitations, including that the Pet scan gives only an indirect measure of levels of tau and beta amyloid, and the tracking substances might not bind only to those proteins.

“This relatively small study adds to evidence that tau may drive the death of brain cells, and could explain why symptoms get worse as tau spreads through the brain,” said Phipps. “While the majority of volunteers in the study were under the age of 65, making it harder to generalise the findings to everyone with the disease, the study highlights the importance of focusing future research efforts on the tau protein.”

By Rob Picheta

Aliens definitely exist, Britain’s first astronaut has said — and it’s possible they’re living among us on Earth but have gone undetected so far.

Helen Sharman, who visited the Soviet Mir space station in 1991, told the Observer newspaper on Sunday that “aliens exist, there’s no two ways about it.”

“There are so many billions of stars out there in the universe that there must be all sorts of different forms of life,” she went on. “Will they be like you and me, made up of carbon and nitrogen? Maybe not.”

Then, in a tantalizing theory that should probably make you very suspicious of your colleagues, Sharman added: “It’s possible they’re here right now and we simply can’t see them.”
Sharman was the first of seven Britons to enter space.

The chemist spent eight days as a researcher on the space mission when she was 27, making her one of the youngest people to enter orbit.

NASA rovers are trawling Mars for evidence of past or present life forms, but humankind’s endless fascination with extraterrestrial life forms has so far proved fruitless.

Sharman is not the only person to speculate that we’ve had brushes with aliens, though.

A former Pentagon official who led a secret government program to research potential UFOs, revealed in 2017, told CNN at the time that he believes there is evidence of alien life reaching Earth.

Elsewhere in her interview, Sharman said there is “no greater beauty than looking at the Earth from up high.”

“I’ll never forget the first time I saw it,” she added.

Sharman also discussed her frustration with observers defining her by her sex. “People often describe me as the first British woman in space, but I was actually the first British person. It’s telling that we would otherwise assume it was a man,” she said.

“When Tim Peake went into space, some people simply forgot about me. A man going first would be the norm, so I’m thrilled that I got to upset that order.”

Dr. Moir’s radical and iconoclastic theories defied conventional views of the disease. But some scientists were ultimately won over.

By Gina Kolata

Robert D. Moir, a Harvard scientist whose radical theories of the brain plaques in Alzheimer’s defied conventional views of the disease, but whose research ultimately led to important proposals for how to treat it, died on Friday at a hospice in Milton, Mass. He was 58.

His wife, Julie Alperen, said the cause was glioblastoma, a type of brain cancer.

Dr. Moir, who grew up on a farm in Donnybrook, a small town in Western Australia, had a track record for confounding expectations. He did not learn to read or write until he was nearly 12; Ms. Alperen said he had told her that the teacher at his one-room schoolhouse was “a demented nun.” Yet, she said, he also knew from age 7 that he wanted to be a scientist.

Dr. Moir succeeded in becoming a researcher who was modest and careful, said his Ph.D. adviser, Dr. Colin Masters, a neuropathologist at the University of Melbourne. So Dr. Masters was surprised when Dr. Moir began publishing papers proposing an iconoclastic rethinking of the pathology of Alzheimer’s disease.

Dr. Moir’s hypothesis “was and is a really novel and controversial idea that he alone developed,” Dr. Masters said.

“I never expected this to come from this quiet achiever,” he said.

Dr. Moir’s theory involved the protein beta amyloid, which forms plaques in the brains of Alzheimer’s patients.

Conventional wisdom held that beta amyloid accumulation was a central part of the disease, and that clearing the brain of beta amyloid would be a good thing for patients.

Dr. Moir proposed instead that beta amyloid is there for a reason: It is the way the brain defends itself against infections. Beta amyloid, he said, forms a sticky web that can trap microbes. The problem is that sometimes the brain goes overboard producing it, and when that happens the brain is damaged.

The implication is that treatments designed to clear the brain of amyloid could be detrimental. The goal would be to remove some of the sticky substance, but not all of it.

The idea, which Dr. Moir first proposed 12 years ago, was met with skepticism. But he kept at it, producing a string of papers with findings that supported the hypothesis. Increasingly, some of the doubters have been won over, said Rudolph Tanzi, a close friend and fellow Alzheimer’s researcher at Harvard.

Dr. Moir’s unconventional ideas made it difficult for him to get federal grants. Nearly every time he submitted a grant proposal to the National Institutes of Health, Dr. Tanzi said in a phone interview, two out of three reviewers would be enthusiastic, while a third would simply not believe it. The proposal would not be funded.

But Dr. Moir took those rejections in stride.

“He’d make a joke about it,” Dr. Tanzi said. “He never got angry. I never saw Rob angry in my life. He’d say, ‘What do we have to do next?’ He was always upbeat, always optimistic.”

Dr. Moir was supported by the Cure Alzheimer’s Fund, and he eventually secured some N.I.H. grants.

Dr. Moir first came to the United States in 1994, when Dr. Tanzi was looking for an Alzheimer’s biochemist to work in his lab. Working with the lab as a postdoctoral fellow and later as a faculty member with his own lab, Dr. Moir made a string of major discoveries about Alzheimer’s disease.

For example, Dr. Moir and Dr. Tanzi found that people naturally make antibodies to specific forms of amyloid. These antibodies protect the brain from Alzheimer’s but do not wipe out amyloid completely. The more antibodies a person makes, the greater the protection against Alzheimer’s.

That finding, Dr. Tanzi said, inspired the development of an experimental drug, which its manufacturer, Biogen, says is helping to treat some people with Alzheimer’s disease. Biogen plans to file for approval from the Food and Drug Administration.

Robert David Moir was born on April 2, 1961, in Kojonup, Australia, to Mary and Terrence Moir, who were farmers. He studied the biochemistry of Alzheimer’s disease at the University of Western Australia before joining Dr. Tanzi’s lab.

Once he learned to read, Ms. Alperen said, he never stopped — he read science fiction, the British magazine New Scientist and even PubMed, the federal database of scientific publications.

“Rob had an encyclopedic knowledge of the natural world,” she said.

He shared that love with his family, on frequent hikes and on trips with his young children to look for rocks, insects and fossils. He also played Australian-rules football, which has elements of rugby as well as American football, and helped form the Boston Demons Australian Rules Football Team in 1997, his wife said.

In addition to his wife, with whom he lived in Sharon, Mass., Dr. Moir’s survivors include three children, Alexander, Maxwell and Holly Moir; a brother, Andrew; and a sister, Catherine Moir. His marriage to Elena Vaillancourt ended in divorce.

As he accepted the coveted Heisman trophy, LSU quarterback Joe Burrow addressed the children in his hometown of Athens, Ohio, where thousands of residents live in poverty.

Burrow struggled to speak, holding back tears as he spoke about the children in his community who go hungry.

“Coming from southeast Ohio, it’s a very impoverished area and the poverty rate is almost two times the national average,” he said in his acceptance speech Saturday. “There’s so many people there that don’t have a lot. And I’m up here for all those kids in Athens and Athens County that go home to not a lot of food on the table, hungry after school. You guys can be up here, too.”

In a matter of hours, the unassuming Appalachian town — home to Ohio University — was launched to national attention, inspiring Athens resident Will Drabold to create a fundraiser for the thousands of residents living under the poverty line.

In just a day, the fundraiser was inundated with donations and quickly shot past its original $50,000 goal. The organizer later updated the goal to $100,000, which was met within hours. The goal had reached $400,000 by Tuesday afternoon.

As of 2 p.m. ET on Tuesday, more than $370,000 had been raised.

“Let’s answer Joey’s call to action by supporting a local nonprofit that serves food to more than 5,000 households in Athens County each year,” the fundraiser page says.

The nonprofit that puts food on Athens County tables

The donations will go to the Athens County Food Pantry, which says it serves over 3,400 meals a week to residents in need.

The pantry also gives bags and boxes of food to Athens families, including non-perishables such as pasta, beans, and canned vegetables, and it hands out fresh produce when it can.

About 30% of the county’s population lives below the poverty line, according to an Ohio poverty report released in February. It is among the poorest counties in the state, all of which are in the Appalachian region.

The nonprofit has identified a number of factors leading to such a high poverty rate, including unemployment and underemployment, lack of reliable transportation and high housing and utility costs.

The pantry said it was overwhelmed by the outpouring of support following Burrow’s speech.

“Many, many thanks to Joe Burrow for shining a light on food insecurity in our area and a very heartfelt thank you to everyone that has donated,” it said in a Facebook post.
Later in the day, Drabold wrote the athlete inspired children in the region.

“Some of these kids don’t get toys for Christmas. Some get their food from the food pantry. You cannot beat the power of role models and inspiration in their lives. None of these kids, who are in the same classrooms Joey was, will ever forget this.”

Nepali Buddhist nuns practise kung fu at the Amitabha Drukpa Nunnery on the outskirts of Kathmandu.

By Sandee LaMotte

Swords swirl around their bodies, coming perilously close to piercing flesh. Blades flashing in the morning sun, the young women twirl, cartwheel and then kick in unison, finishing their graceful movements in a centuries old kung fu fighting stance.

Dressed alike with matching shaved heads, the women and girls finish their daily exercise and move on to their other duties as part of the Kung Fu Nuns of the Himalayas, a name they have proudly adopted.

Jigme Yangchen Ghamo has lived at the Druk Amitabha Mountain Nunnery perched high in the mountains outside Kathmandu since she was 10 years old.
“We are the only nunnery in all of the Himalayas doing deadly martial arts,” Ghamo told CNN’s Great Big Story in June. “This is a lifelong vow that I made to the Drukpa Order, and I am very proud of my practice.”

The Drukpa Order is a branch of Himalayan Buddhism, a faith which traditionally considers women second-class citizens. According to Buddhist narratives, a woman cannot achieve spiritual enlightenment unless she is reborn as a man.

“The idea was that as long as the nuns cook and clean for the monks, they can come back as a monk in their next lifetime and then become enlightened,” said Carrie Lee, the former president of Live to Love, a non-governmental organization that works closely with the nunnery to supply aid to the region.

According to Lee, discrimination toward women is a way of life in Nepal and surrounding nations. Girls are considered a burden and are frequently aborted; if they live, they have limited access to healthcare or education. They are often sold off to traffickers or marry young; wife beating and other types of spousal violence is common.

His Holiness Gyalwang Drukpa, the spiritual leader of the Drukpa lineage, says as a child he believed the Buddhist beliefs about women to be misguided. In the early 2000s he began to promote the nuns to leadership positions.

t wasn’t always well received. Local traditionalists called the action “blasphemous,” Lee said, “and then they started harassing the nuns and assaulting them.”

To teach the nuns self-defense, Drukpa hired a kung fu teacher in 2008. But His Holiness also hoped the training would improve the nun’s confidence and self-esteem.

“I consider the kung fu art, martial art, an education,” he told actress Susan Sarandon in a 2014 interview. “I’m very proud of the nuns.

“I have been breaking through all these barriers,” he added. “Whatever the Buddhist people say I don’t mind and I don’t care.”

A healthy life

“We wake up at 3 a.m., we meditate, we bicycle and we train for three hours,” Ghamo said. “The Drukpa Order is not for lazy people.”

In addition to kung fu practice with swords, sticks and flags, the women jog and run up and down stairs to boost their fitness. They even learn to break bricks with their hands.

All of the physical work has a spiritual purpose, Ghamo said. “Kung fu trains us to focus our minds for meditation.”

Martial arts are known for their health benefits. A 2018 study found “hard” martial arts like kung fu can improve balance and cognitive functions that decline with age, while a 2016 study found kung fu and karate helped with blood sugar control.

Another ancient martial art, Tai Chi, has been more thoroughly studied. Research shows Tai Chi can improve bone mineral density, reduce blood pressure, lower cholesterol, and reduce harmful inflammation.

And the mental health benefits are just as strong. The calming, meditative trance needed to do a Tai Chi series has been shown to greatly reduce anxiety and stress, even lowering levels of cortisol, the stress hormone, in the blood of participants.

‘Landslides, avalanches and earthquakes’

When a devastating 7.9 earthquake took the lives of 9,000 people in Nepal in 2015, the nuns from Druk Amitabha Mountain Nunnery were some of the first relief workers on the scene.

Supported by the Live to Love organization, the nuns walked to villages that government and traditional relief organizations considered too dangerous to visit.

“When the earthquake hit, our kung fu training helped us to be brave and strong,” Ghamo said. “We survived the landslides, avalanches and earthquakes.”

Later the nuns were able to “do a medical helicopter rescue, truck rescues, food and medicine distribution, provide solar power, and more,” they wrote on their website, even building 201 new homes after clearing the rubble.

During the cleanup, Lee said, the nuns saw young girls being given away or sold off to potential human traffickers and decided to take action. They organized bi-yearly bicycle trips, taking months to cover thousands of treacherous miles between Kathmandu and Ladakh, India. They stop at tiny villages along the way to spread a message about the value of girls and the dangers of human trafficking.

“We talk about equality and safety,” Ghamo said. “We wanted to show everyone that if nuns can ride bicycles, then girls can do anything.”

By showing that girls could survive the mountainous terrain, they were sending the message that “girls were strong enough to farm” and thus worth keeping, Lee explained. “They started raising awareness about what actually happens to girls when you give them away.”

Many of the mothers had encouraged their girls to leave, hoping they would have a better life, Lee said. “And now when the nuns go back, these families come up to them and say, “We had no idea where our girls are going. We’re much more protective of them now.”

His Holiness Gyalwang Drukpa, their spiritual leader, joins the nuns on most of their bicycle trips. His presence adds weight to their fight for women’s rights, especially in the most traditional villages.

“Because of his religious authority, equality becomes a religious mandate,” Lee said. “Respecting women becomes a religious imperative wherever he goes.”
The effort appears to be paying off.

“In the past 15 years, I’ve noticed a huge shift in some of these villages,” Lee said. “Before, if I sat down with meetings, it was predominantly men. Now women are so much more vocal in these meetings. Now you see female police officers, you see female politicians and leaders.”

‘Fearless one’

The nuns have added a green theme to their good works. Each year they do a “Eco-Pad Yatras,” a 400 plus mile hike picking up plastic litter and educating locals on ways to protect their local environments.

Many of the nuns are trained solar technicians, others assist doctors in the Live to Love eye camps, where cataracts surgeries are free of charge. Other activities include music, dance, theater, and animal rescue and care.

When Lee first began volunteering 20 years ago, the nunnery was home to about 30 nuns. Today there are more than 800, ranging in age from eight to 80. There is a waiting list for young girls who want to join the “Kung Fu Nun” revolution.

All of the nuns bear the first name of Jigme, which means “fearless one” in Tibetan.

“I learned I can do anything a man can do,” Ghamo said. “Kung fu has trained me to be confident, strong and happy. The teachings help me put my compassion into action.”