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Flaky Scalps Have a Unique Fungal Microbiome Christopher Intagliata | December 20, 2019
There's a lot of advertising mythology about what causes dandruff. Like this: <<CLIP: "Here's why clean scalp is important. Your hair roots must breathe. Or there's trouble. Deep trouble. Dandruff.">>
"Dandruff itself is actually a very, very complicated condition."
Barry Murphy, a microbiologist and molecular biologist at Unilever in the UK, says dandruff is a perfect storm of flakiness—involving your fungal microbiome, the health and oiliness of the skin on your scalp, even weather!
His team set out to investigate the microbial component. They sequenced DNA from the heads of people with healthy hair, and others with dry, dandruffy scalps—none of whom had used anti-dandruff shampoo within the last six months.
As previous studies have found, they spotted ten times as much of a type of fungus called Malassezia on dandruff scalps, versus the healthy cohort. But they also found that populations of a bacterium called Staphylococcus capitis spiked on flaky scalps.
"Really, really interestingly, we found there was approximately 100 times more of this bacteria on a dry or a dandruff scalp than there was on a healthy scalp."
But it's still a mystery why it's there… or, what it's doing. The results are in the journal PLOS ONE. [Sally G. Grimshaw et al, The diversity and abundance of fungi and bacteria on the healthy and dandruff affected human scalp]
Murphy's employer Unilever makes its own anti-dandruff products. So this could be useful information someday. But rather than just zapping scalp fungi with anti-fungal compounds, like most of today's anti-dandruff shampoos do, Murphy says the goal might be to make a more gentle product.
"It should be about trying to restore an equilibrium. It should be about microbiome balance. It should be about the very fact that we've lived in harmony with these microbes for millions and millions of years."
Either way, it seems the old lore that a dandruffy scalp just needs a thorough 'cleaning'...might be a little flaky.
Source: Scientific American https://www.scientificamerican.com/podcast/episode/flaky-scalps-have-a-unique-fungal-microbiome/
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Homo erectus’ last known appearance dates to roughly 117,000 years ago Bruce Bower | December 18, 2019
[Time 2] Homo erectus, a humanlike species that dispersed from Africa into parts of Europe and Asia roughly 2 million years ago, eventually reached the Indonesian island of Java before dying out. Scientists say they have now resolved a controversy over just how long ago the last known H. erectus inhabited the Southeast Asian island.
New evidence narrows the timing of this hominid’s final stand on Java to between 117,000 and 108,000 years ago, says a team led by geochronologists Yan Rizal of Indonesia’s Bandung Institute of Technology and Kira Westaway of Macquarie University in Sydney. The scientists present their results December 18 in Nature.
If the findings hold up to scrutiny, the fossils would be the last known occurrence of H. erectus anywhere in the world, and would show that the hominid was part of a complex interplay among different Homo species in Southeast Asia that started more than 100,000 years ago.
Excavations at Java’s Ngandong site from 1931 to 1933 uncovered 12 skullcaps and two lower leg bones from H. erectus. Since then, uncertainty about how Ngandong sediment layers formed and confusion about the original location of the excavated fossils has led to dramatically contrasting age estimates for the finds.
A 1996 report in Science dated the Ngandong specimens to between 53,000 and 27,000 years ago, suggesting that H. erectus had lived alongside Homo sapiens in Indonesia. But a more recent analysis greatly increased the estimated age of the Java fossils, dating them to around 550,000 years ago.
In the new study, researchers uncovered the spot where H. erectus fossils had been found, and then excavated and dated nonhuman animal fossils from the site, including large, hoofed creatures related to water buffalo. Those estimates relied on measures of radioactive uranium decay in bones and of tooth enamel damage from natural radioactivity in the soil and from cosmic rays, energetic particles from space that continually bombard Earth. [316 words]
[Time 3] Dates of sediment above and below the fossil site, and of a nearby mountain formation that created those deposits, aligned with the new age estimate for H. erectus.
Evidence of humans in Indonesia extends no earlier than 73,000 years ago. H. erectus last existed on Java at least 35,000 years before that, meaning it’s unlikely the two overlapped, says study coauthor Russell Ciochon, a paleoanthropologist at the University of Iowa in Iowa City.
Previous research indicates that H. erectus arrived on Java by about 1.6 million years ago, Ciochon says. It’s possible that Homo floresiensis, controversial half-sized hominids nicknamed hobbits, and recently reported Homo luzonensis in the Philippines evolved from H. erectus, he speculates. Hobbit and H. luzonensis fossils display some traits like those of H. erectus. Evidence suggests that H. luzonensislived on the island of Luzon at least 50,000 years ago, around the same time that H. floresiensis inhabited the Indonesian island of Flores.
Considering uncertainties in assigning precise ages to the Ngandong fossils, H. erectus may have lived there 10,000 to 20,000 years earlier or later than estimated in the new report, says paleoanthropologist Susan Antón of New York University, who was not involved in the new study. Even so, it’s still clear that humans and H. erectus didn’t overlap on Java, she says.
The new timeline supports, at a minimum, a scenario in which at least three now-extinct Homo species inhabited parts of Southeast Asia when H. sapiens was making early moves out of Africa, says paleoanthropologist Matthew Tocheri of Lakehead University in Thunder Bay, Canada. Tocheri also did not take part in the new research.
“Now we just need to figure out what exactly happened when Homo sapiens first arrived in Southeast Asia,” says Tocheri. [289 words]
Source: Science News https://www.sciencenews.org/article/homo-erectus-last-known-appearance-roughly-117000-years-ago
These science claims from 2019 could be big deals — if true Cassie Martin | December 18, 2019
[Time 4] Discoveries about dinosaurs’ death knell, a watery exoplanet, a new hominid species and more are keeping us on the edge of our seats. But these reports require more proof before they can earn a spot on our list of top stories of the year.
Dino doomsday When an asteroid smashed into Earth about 66 million years ago, it triggered an immense earthquake. A fossil site in North Dakota records the mayhem in the hours after impact, scientists reported in the Proceedings of the National Academy of Sciences. But what’s more tantalizing is what the researchers may have left out of their scientific paper. Robert DePalma, a paleontologist at the University of Kansas in Lawrence and an author on the paper, told the New Yorker that the team found fossilized dinosaurs, pterosaurs and even feathers at the site. Because so few dinosaur fossils from just before the impact have been found, some scientists think that the animals were already dying out. If dinosaur fossils do exist at the site, that’s more evidence that the asteroid impact was to blame.
Soggy skies Water vapor detected in the atmosphere of an exoplanet 110 light-years away from Earth had astronomers saying K2 18b is the first known planet orbiting a distant star that might have liquid water. K2 18b might even have water clouds and rain, scientists suggest. Observations with NASA’s James Webb Space Telescope, slated to launch in 2021, could help determine if and how much liquid water, thought to be a key ingredient for life, K2 18b has. But even if the exoplanet is awash in the wet stuff, that doesn’t mean the planet is habitable. [274 words]
[Time 5] What lies beneath A cache of tiny animal carcasses was dredged up from Antarctica’s perpetually ice-covered Lake Mercer, scientists revealed this year. The find was a surprise because this extreme environment was thought to be friendly only for microbes. The limits of habitability may be less narrow than previously thought. But it’s also possible that the remains — including what look like tardigrades, crustaceans, spiders and worms — were carried into the lake by ice or water.
Hello, Homo luzonensis Fossils discovered in a Philippine cave suggest that an unknown hominid species roamed the island now called Luzon at least 50,000 years ago. The proposed new species, dubbed Homo luzonensis, lived around the same time that small hominids wandered the Indonesian island called Flores. The shape and size of some of the fossils match corresponding bones from known Homo species. But the combination of features is unique, researchers say. If confirmed as a separate species, H. luzonensis would be the latest addition to the human evolutionary family tree. The find would also indicate that several Homo groups inhabited East Asia and Southeast Asian islands by the time humans reached southern China, complicating scientists’ view of hominid evolution in Asia.
Stellar jet-setter When two neutron stars crashed into each other, as reported in Science News’ top story of 2017, the collision blasted a jet of charged particles into space, new observations suggest. The find supports a theory that mysterious flashes of high-energy light called short gamma-ray bursts are actually jets from neutron star collisions. But researchers will need to observe more of these stellar smashups to figure out if the jets are the norm, or if the 2017 jet was a fluke. [279 words]
[Time 6] Sixth sense Similar to birds and fish, humans may sense Earth’s magnetic field, a study of brain waves suggests. In lab tests, people displayed a distinct brain wave pattern when exposed to an Earth-strength magnetic field. But the pattern formed only when the field pointed and moved in a certain way. Even if the finding is confirmed, it’s not clear what we would do with this “sixth sense,” or how we would pick up the signal.
Clearing the way Flickering lights and clicks improved memory in mice with signs of Alzheimer’s disease. The light and sounds boosted gamma waves in the brain, which seemed to wipe away disease-related plaques. Mice that received treatment had fewer amyloid-beta plaques in areas of the brain usually hit hard by the disease, plus less of a harmful version of tau protein. Plaque-eating immune cells were kicked into a feeding frenzy, scientists reported. If the treatment works in people (tests are now under way), it would open a new way to target the degenerative disease. But many treatments that have reduced signs of the disease in mice haven’t had the same effect in humans. [189 words]
Source: Science News https://www.sciencenews.org/article/big-if-true-science-stories-2019-yir
Wildlife wins: 7 good-news stories from 2019 Rachel Fobar | December 20, 2019
[Paraphrase 7] Optimism can be in short supply when it comes to wildlife and conservation. This year alone, Masai giraffes were declared endangered, fires in the Amazon devastated jaguars, turtles, and other wildlife, and cheetah researchers accused of spying were sentenced to years in prison in Iran. Demand for wildlife and wildlife products—such as pet turtles, lion bone, and shatoosh, scarves made from the fleece of rare Tibetan antelopes—is thought to be on the rise. And alleged major poaching boss Bach “Boonchai” Mai, charged with smuggling rhino horns, was released after a key witness recanted.
But largely thanks to conservationists and animal advocates, there were success stories too, especially when it comes to protecting wildlife from crime and exploitation. Here are some ways wildlife benefited in 2019:
At the global conference on wildlife trade, more species received protections. Nine animals received protections from international trade, and more than 130 species won protections for the first time at this year’s meeting, in Geneva, of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), the global agreement that regulates cross-border trade in wildlife. Giraffes and mako sharks, respectively listed as vulnerable and endangered by the International Union for Conservation of Nature, the global authority on the conservation status of species, were two animals given enhanced protection. Neither can be traded unless it can be shown that doing so wouldn’t threaten the survival of their populations in the wild. Whereas giving animals stronger protections signals that trade has hurt those species, it may encourage governments to do more to protect them.
Vaquita babies have been spotted off the coast of Mexico. Vaquitas, which are the smallest porpoises in the world, have fallen to the razor’s edge of extinction, with about 10 remaining individuals—but last month, scientists glimpsed mothers with calves in the Gulf of California. Vaquitas are collateral damage of the lucrative market for traditional medicine. Fishermen anchor gillnets to the ocean floor to catch fish called totoaba, whose valuable swim bladders are traded illegally to China to treat ailments such as arthritis. Vaquitas need to breathe air but get trapped in the nets and suffocate. “As long as there are some animals left, there’s hope,” Eva Hidalgo, science coordinator for the marine conservation group Sea Shepherd, told National Geographic earlier this year. “We need to do our best to make sure that they do have a chance of recovering, no matter how small that chance may be.”
Chinese insurance will no longer cover pangolin scales. In August, the Chinese government announced that its insurance funds would no longer cover traditional medicine containing pangolin scales, used to treat ailments from difficulty with lactation to poor circulation. All eight species of the scaly, anteater-like mammals are threatened with extinction. Their scales are used in more than 60 commercially produced curatives, according to the nonprofit China Biodiversity and Green Development Foundation. The National Medical Insurance and the Human Resource and Social Security Bureau also announced that products derived from hawksbill sea turtles, sea horses, coral, saiga antelope antlers, among others, would no longer be covered either. Daisy He, a Beijing-based lawyer with the international firm CMS, told National Geographic in an email, “The Chinese government and the Chinese public have noticed the importance of protecting these animals.”
African elephants can only rarely be caught and sent to faraway zoos. Thanks to a new CITES resolution, elephants from Botswana, Zimbabwe, Namibia, and South Africa can be exported only to other African countries where elephants live or used to live, unless it can be shown that sending them elsewhere would result in a conservation benefit for the species. This stops the controversial practice of selling wild-caught elephants to zoos around the world. Research has shown that elephants are highly intelligent, social creatures that create lifelong bonds with other animals. They mourn their dead and are capable of empathy, among other things. “It’s a huge victory for animal welfare that the abduction of baby elephants from their families to be held in zoos has been banned,” Frank Pope, CEO of the Nairobi-based nonprofit Save the Elephants told National Geographic at the time of the decision.
International officials cracked down on wildlife crime. Global enforcement bodies—including Interpol, Europol, and the World Customs Organization—conducted Operation Thunderball, the widest-ranging wildlife crime sting ever, and Operation Blizzard, the largest reptile trade bust to date. Thunderball involved 109 countries and nearly 2,000 seizures of protected wildlife. It sought to reveal crime hot spots and prevent wildlife crime, with the ultimate goal of “dismantling of criminal networks,” said Roux Raath, the World Customs Organization’s environment program manager. Blizzard, which identified small-scale illegal traders, resulted in 12 arrests and more than 4,000 seizures of live reptiles. Sergio Tirro, a project manager for environmental crime with Europol, hopes law enforcement can elicit information from the dozen suspects to build cases against top traffickers. “Our focus is organized crime groups behind the illegal trade,” Tirro told National Geographic.
The Russian government released the final group of animals from the notorious “whale jail.” In 2018, four Russian companies that supply marine mammals to aquariums illegally caught nearly 100 beluga whales and orcas and held them in Srednyaya Bay, in Russia’s far east. With the onset of winter, the animals remained in holding pens as surface ice formed. Most were reported to have skin lesions, and they appeared to be suffering. Over the course of 2019, the animals were gradually freed, and in November, authorities transported the remaining 50 belugas to Uspeniya Bay, about 60 miles away. Although not their native habitat, the bay was considered the best option, given funding constraints.
Technological developments help track animals and block the illegal wildlife trade. Technologists with the artificial intelligence company Synthetaic and National Geographic Labs, an initiative that helps harness technology for conservation, have developed a system that uses artificial intelligence and airplane-mounted cameras to identify and count animals in near-real time across huge distances. The researchers have already successfully scanned both Garamba National Park, in Democratic Republic of the Congo, and Lewa Wildlife Conservancy, in Kenya. And for the first time, scientists detailed using a handheld gene sequencing device called MinION to determine the species of shark fins in a fish market northwest of Mumbai. This gizmo can also can be used to identify ivory, pangolin scales, and other illegally traded wildlife products. “The MinION could be a game changer in that it can be used by wildlife officials locally,” Shaili Johri, a post-doctoral biology researcher at San Diego State University, told National Geographic in an email. [1096 words]
Source: National Geographic https://www.nationalgeographic.com/animals/2019/12/wildlife-wins-of-this-year-2019/
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发表于 2019-12-28 16:08:36
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