A Porous Core on Saturn's Icy Moon Enceladus May Fuel Its Mysterious Geysers

Artist's concept of the Cassini spacecraft flying through the plumes of Enceladus.

In 2005, NASA’s Cassini spacecraft identified geysers on Saturn’s moon Enceladus that were blasting plumes of ice and vapor into space. Now a new study suggests that the secret to these geysers lies in Enceladus’s core  —  and that related hydrothermal activity may have existed long enough to allow life to arise on the icy moon.

Enceladus is famous for displaying dozens of erupting geysers at the south pole, in view of the Cassini spacecraft, which was in the system between 2004 and 2017.

Scientists originally theorized that the tidal forces of Saturn on the small moon caused the dozens of erupting geysers around its south pole, but later calculations testing this idea showed that the water would have frozen over within 30 million years. (The solar system is over 4.6 billion years old.)

To keep the water flowing, “an abnormally high heat power (more than 20 billion watts) is required, as well as a mechanism to focus endogenic [below-surface] activity at the south pole,” the authors of the new study write in the journal Nature Astronomy. The research was led by Gaël Choblet, a University of Nantes researcher in France who specializes in planetary interiors.

The research team suggests that the additional heat could be generated from tidal friction inside the core, which they described as rocky and unconsolidated, meaning that the core is loosely held together. This porous core allows water to move up in narrow, hot columns that burst through hotspots on the seafloor. The model further shows that the activity could continue for at least a few tens of millions of years, and perhaps billions of years.

“The release of heat in narrow regions favors intense interaction between water and rock, and the transport of hydrothermal products from the core to the [water] plume sources,” the authors write. “We are thus able to explain the main global characteristics of Enceladus: global ocean, strong dissipation, reduced ice-shell thickness at the south pole, and seafloor activity.”

The authors say that Enceladus’s core is likely a metal-rock nucleus with a lot of water-filled areas, as well as many iron-bearing hydrated materials; the abundance of these materials, they added, would hint as to how much water is in the core. The models included information from parameters such as the libration (oscillation or wobbling) of Enceladus that was detected by Cassini, observed sediments flowing underneath glaciers, and loading tests on granular materials.

These findings have implications for potential life on Enceladus. Cassini’s detection of hydrogen gas in one of the moon’s plumes fueled the idea that hydrothermal vents lie deep inside the moon’s subsurface ocean. They might possibly resemble those that are found on Earth, where chemical reactions could theoretically have produced the beginnings of microbial life on our planet. If so, then similar hydrothermal activity taking place on Enceladus for billions of years may have given potential life an opportunity to evolve on the icy moon.

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The Hole in the Ozone Layer Is at It's Smallest in Nearly Three Decades

Ozone Hole

Higher temperatures over Antarctica this year shrank the hole in the ozone layer to the smallest it's been since 1988.

The ozone hole is a depletion of ozone gas (O3) in the stratosphere above Antarctica. The three-oxygen molecule is toxic at ground level, but high in the atmosphere, it deflects dangerous ultraviolet rays from reaching Earth's surface.

In 1985, scientists first detected the hole in the ozone layer and realized it was being caused by man-made chlorine and bromine, often found in chlorofluorocarbons (CFCs), compounds used as refrigerants. In 1987, the Montreal Protocol initiated the phase-out of these chemicals. As they gradually leave the atmosphere, the ozone hole will heal, and scientists expect it to return to 1980s size by 2070.

Natural variability affects this healing year-to-year, however.

"The Antarctic ozone hole was exceptionally weak this year," Paul Newman, chief scientist for Earth Sciences at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. "This is what we would expect to see given the weather conditions in the Antarctic stratosphere."

Weather and ozone

In the upper atmosphere, CFCs break apart, freeing chlorine to react with ozone molecules, a reaction that creates oxygen and chlorine monoxide. Similar reactions occur with bromine. Polar stratospheric clouds, which form in frigid temperatures, speed up this process by providing surfaces for the reactions to occur on. That's why the ozone hole worsens in the Southern Hemisphere winter.

The hole in Earth's protective ozone layer that forms over Antarctica each September was the smallest seen since 1988, according to NASA and NOAA.

Higher temperatures in the stratosphere, on the other hand, allow ozone to remain more stable in the atmosphere, meaning they keep the ozone hole smaller on a year-to-year basis. This year on Sept. 11, NASA measured the maximum extent of the hole at 7.6 million square miles (19.6 million square kilometers), 2.5 times the size of the United States.

That was smaller than in 2016, when the maximum extent was 8.9 million square miles (22.2 million square km), also a below-average size. According to NASA, the average maximum extent of the ozone hole since 1991 has hovered at about 10 million square miles (25.8 million square km).

Historic high

However, scientists said that two years of lower-than-usual ozone hole extent isn't a sign that the ozone layer is healing faster than expected. Instead, it's a side effect of the Antarctic vortex — a low-pressure system that rotates clockwise above the southernmost continent — undergoing a few years of instability and warmth, which prevented the proliferation of polar stratospheric clouds.

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Hubble sees nearby asteroids photobombing distant galaxies

Asteroid Trails Streak Across This Deep-Space View of Thousands of Galaxies. Photobombing asteroids from our solar system have snuck their way into this deep image of the universe taken by NASA's Hubble Space Telescope. These asteroids are right around the corner in astronomical terms, residing roughly 160 million miles from Earth. Yet they've horned their way into this picture of thousands of galaxies scattered across space and time at inconceivably farther distances.

Like rude relatives who jump in front your vacation snapshots of landscapes, some of our solar system's asteroids have photobombed deep images of the universe taken by NASA's Hubble Space Telescope. These asteroids reside, on average, only about 160 million miles from Earth-right around the corner in astronomical terms. Yet they've horned their way into this picture of thousands of galaxies scattered across space and time at inconceivably farther distances.

This Hubble photo of a random patch of sky is part of a survey called Frontier Fields. The colorful image contains thousands of galaxies, including massive yellowish ellipticals and majestic blue spirals. Much smaller, fragmentary blue galaxies are sprinkled throughout the field. The reddest objects are most likely the farthest galaxies, whose light has been stretched into the red part of the spectrum by the expansion of space.

Intruding across the picture are asteroid trails that appear as curved or S-shaped streaks. Rather than leaving one long trail, the asteroids appear in multiple Hubble exposures that have been combined into one image. Of the 20 total asteroid sightings for this field, seven are unique objects. Of these seven asteroids, only two were earlier identified. The others were too faint to be seen previously.

The trails look curved due to an observational effect called parallax. As Hubble orbits around Earth, an asteroid will appear to move along an arc with respect to the vastly more distant background stars and galaxies.

This parallax effect is somewhat similar to the effect you see from a moving car, in which trees by the side of the road appear to be passing by much more rapidly than background objects at much larger distances. The motion of Earth around the Sun, and the motion of the asteroids along their orbits, are other contributing factors to the apparent skewing of asteroid paths.

All the asteroids were found manually, the majority by "blinking" consecutive exposures to capture apparent asteroid motion. Astronomers found a unique asteroid for every 10 to 20 hours of exposure time.

The Frontier Fields program is a collaboration among NASA's Great Observatories and other telescopes to study six massive galaxy clusters and their effects. Using a different camera, pointing in a slightly different direction, Hubble photographed six so-called "parallel fields" at the same time it photographed the massive galaxy clusters. This maximized Hubble's observational efficiency in doing deep space exposures. These parallel fields are similar in depth to the famous Hubble Deep Field, and include galaxies about four-billion times fainter than can be seen by the human eye.

This picture is of the parallel field for the galaxy cluster Abell 370. It was assembled from images taken in visible and infrared light. The field's position on the sky is near the ecliptic, the plane of our solar system. This is the zone in which most asteroids reside, which is why Hubble astronomers saw so many crossings. Hubble deep-sky observations taken along a line-of-sight near the plane of our solar system commonly record asteroid trails.

Read more at Science Daily

Newly discovered orangutan species is 'among the most threatened great apes in the world'

Photo of a Pongo tapanuliensis skull.

Scientists have long recognized six living species of great ape aside from humans: Sumatran and Bornean orangutans, eastern and western gorillas, chimpanzees, and bonobos. But researchers reporting in Current Biology on November 2 have now made it seven, based on a collection of evidence showing that an isolated population of orangutans living in Sumatra is actually its own unique species. They've named the new species the Tapanuli orangutan (Pongo tapanuliensis).

Unfortunately, the researchers say, there are only about 800 Tapanuli orangutans left. Those that remain are also under threat from loss of lowland habitat and hunting, which makes this newly discovered species among the most threatened great ape species in the world.

"It isn't an everyday event that we find a new species of great ape, so indeed the discovery is very exciting," said Michael Krutzen of the University of Zurich in Switzerland, senior author of the study.

"Great apes are among the best-studied species in the world," added Erik Meijaard of the Australian National University. "If after 200 years of serious biological research we can still find new species in this group, what does it tell us about all the other stuff that we are overlooking: hidden species, unknown ecological relationships, critical thresholds we shouldn't cross? Humans are conducting a vast global experiment, but we have near-zero understanding of what impacts this really has, and how it could ultimately undermine our own survival."

The new orangutan species lives in the Batang Toru area in North Sumatra, Indonesia. While there had been rumors, no one was sure that this population of orangutans existed until 1997. They live south of what had been the known range for Sumatran orangutans.

Earlier studies suggested that the group differed from other orangutans behaviorally and at the genetic level, but it wasn't clear that those differences were enough to support its designation as a new species. The breakthrough came in 2013, when the research team including Meijaard got access to a skeleton belonging to a Batang Toru orangutan killed in a human-animal conflict. Careful studies of the animal revealed consistent differences in its skull and teeth.

A sophisticated analysis of 37 orangutan genomes now shows that the deepest split in the evolutionary history of living orangutans occurred more than three million years ago, between the Batang Toru population and Bornean orangutans to the north of Lake Toba. Bornean and Sumatran orangutans separated only much later, less than 700,000 years ago. Behavioral and ecological evidence lends further support for the notion that the orangutans living in Batang Toru are a separate species, the researchers said.

"The Batang Toru orangutans appear to be direct descendants of the initial orangutans that had migrated from mainland Asia, and thus constitute the oldest evolutionary line within the genus Pongo," said Alexander Nater, also of the Unversity of Zurich. "The Batang Toru population was connected to populations to the north until 10,000 or 20,000 years ago, after which it became isolated."

The findings mean that there are now 800 fewer Sumatran orangutans than previously thought. The Tapanuli orangutans are also severely threatened by hunting and the proposed development of a hydroelectric dam that would flood large parts of their best habitat if implemented. That's especially discouraging given that previous analyses suggest a mortality rate of less than one percent per year would still be enough to drive the Tapanuli orangutans extinct.

Read more at Science Daily

Cells driving gecko's ability to re-grow its tail identified

This is a Leopard gecko.

A U of G researcher is the first to discover the type of stem cell that is behind the gecko's ability to re-grow its tail, a finding that has implications for spinal cord treatment in humans.

Many lizards can detach a portion of their tail to avoid a predator and then regenerate a new one. Unlike mammals, the lizard tail includes a spinal cord.

Prof. Matthew Vickaryous found that the spinal cord of the tail contained a large number of stem cells and proteins known to support stem cell growth.

"We knew the gecko's spinal cord could regenerate, but we didn't know which cells were playing a key role," said Vickaryous, lead author of the study recently published in the Journal of Comparative Neurology. "Humans are notoriously bad at dealing with spinal cord injuries so I'm hoping we can use what we learn from geckos to coax human spinal cord injuries into repairing themselves."

Geckos are able to re-grow a new tail within 30 days -- faster than any other type of lizard.

In the wild, they detach their tails when grabbed by a predator. The severed tail continues to wiggle, distracting the predator long enough for the reptile to escape.

In the lab, Vickaryous simulates this by pinching the gecko's tail causing the tail to drop. Once detached, the site of the tail loss begins to repair itself, eventually leading to new tissue formation and a new spinal cord. For this study, the biomedical sciences professor, along with PhD student Emily Gilbert, investigated what happens at the cellular level before and after detachment.

They discovered that the spinal cord houses a special type of stem cell known as the radial glia. These stem cells are normally fairly quiet.

"But when the tail comes off everything temporarily changes," he said. "The cells make different proteins and begin proliferating more in response to the injury. Ultimately, they make a brand new spinal cord. Once the injury is healed and the spinal cord is restored, the cells return to a resting state."

Humans, on the other hand, respond to a spinal cord injury by making scar tissue rather than new tissue, he added. The scar tissue seals the wound quickly, but sealing the injury prevents regeneration.

"It's a quick fix but in the long term it's a problem."

"This may play a role in why we have a limited ability to repair our spinal cords. We are missing the key cells types required."

This study is part of a series of investigations into the regenerative abilities of the gecko's central nervous system. The next step is to examine how the gecko is able to make new brain cells, said Vickaryous.

Read more at Science Daily

The First Americans May Have Migrated Along a Coastal ‘Kelp Highway’

Kwakiutl tribe of the Pacific Northwest rowing in canoes.

A conventional belief about the first settlement of the Americas holds that people with ancestry from Siberia in northeastern Asia traveled into North America across the Bering Strait when it was exposed as a land bridge during the last ice age roughly 13,500 years ago.

These first settlers were thought to be the likely creators of the prehistoric Clovis culture. Remnants of this culture primarily consist of stone tools that were first excavated near Clovis, New Mexico, in 1932. Little is known about the Paleo-Indians who made the tools, but the remains of an infant boy named Anzick-1 have been associated with the Clovis. DNA analysis of Anzick-1 in 2014 revealed a genetic connection to modern Native American populations.

Although the “Clovis-first” theory concerning the earliest peopling of the Americas remained the accepted view throughout much of the 20th century, confidence in it started to crumble in the late 1980s. Archaeologists then began to find evidence for extensive seafaring and maritime colonization of places like the Ryukyu Islands off eastern Asia. Evidence for American settlements earlier than 13,500 years ago has also been mounting.

Clovis culture tools from the Rummells-Maske Site of Cedar County, Iowa.

“Understanding when, how, and who colonized the Americas remains one of the most challenging and enduring questions in archaeology,” Torben Rick of the National Museum of Natural History’s Department of Anthropology told Seeker. “One of the most important questions in American archaeology is: Who were the first Americans and how and when did they arrive?”

Todd Braje of the San Diego State University Department of Anthropology agrees.

“Thirty years ago, we thought we had all the answers,” he said. “Now, there are more questions than answers.”

Nevertheless, a somewhat clearer view of early American settlement is coming to  light,  and one that Rick, Braje, and their colleagues address in a new paper in the journal Science.

“There is a coalescence of data — genetic, archaeological, and geologic — that support a colonization around 20,000–15,000 years ago,” Rick said. “This doesn’t preclude earlier  migrations,  or suggest that we should not investigate earlier migrations, but a growing body of evidence is building on intensive research that supports the 20,000–15,000 years ago  timeframe,  and evidence for earlier migrations is problematic and speculative.”

In the paper, he and his colleagues mention — and question — the recent discovery of the Cerutti Mastodon site in San Diego County, California. The site contains the remains of a 130,700-year-old juvenile male mastodon, which some scientists believe was butchered by hominid that was not necessarily Homo sapiens.

One such researcher is Daniel Fisher, director of the University of Michigan Museum of Paleontology. He told Seeker that, “based on decades of experience seeing sites with evidence of human activity, and also a great deal of work on modern material trying to replicate the patterns of fractures that we see, I really know of no other way that the material of the Cerutti Mastodon site could have been produced than through human activity.”

If validated, the Cerutti find would blow a mammoth-sized hole in virtually all theories concerning when and how the Americas were first settled, given its extremely early age. For now, though, Braje, Rick, and many other archaeologists are supporting the emerging “kelp highway hypothesis.”

Fish swim through a kelp forest at the Channel Islands National Park.

Braje said that “a coastal migration into the Americas was the most likely initial colonization event,” and that “the first Americans likely arrived along the Pacific coast, not crossing the open Pacific, but migrating along the Pacific Rim in boats in a step-wise fashion” starting around 20,000 years ago.

The region then, and now, is rich in aquatic and terrestrial natural resources, with a productive kelp forest and associated marine ecosystems at sea level. The researchers explained that the kelp forest extended as far south as Baja California. At that point, productive mangrove and other aquatic habitats would have been available along the Central American coast. The kelp forest then started up again in northern Peru, reaching as far south as Tierra del Fuego.

It is possible that the first people migrating to the Americas along the kelp highway and perhaps other entrance points came from different locations and cultures.

“However, there were likely limited migration corridors during the 25,000–15,000-year-ago interval,” Braje noted. “The ice-free corridor route was closed, so a terrestrial migration during this interval is unlikely. But there may have been multiple migrations during and after this interval.”

Read more at Seeker

Humans don't use as much brainpower as we like to think

A tiny treeshrew brain saps just as much of the body's energy as a human brain, researchers report. Shown in red are the blood vessels that deliver glucose to fuel cellular activities.

For years, scientists assumed that humans devote a larger share of their daily calories to their brains than other animals. Although the human brain makes up only 2 percent of body weight, it consumes more than 25 percent of our baseline energy budget.

But a study published Oct. 31 in the Journal of Human Evolution comparing the relative brain costs of 22 species found that, when it comes to brainpower, humans aren't as exceptional as we like to think.

"We don't have a uniquely expensive brain," said study author Doug Boyer, assistant professor of evolutionary anthropology at Duke University. "This challenges a major dogma in human evolution studies."

Boyer and his graduate student Arianna Harrington decided to see how humans stack up in terms of brain energy uptake.

Because energy travels to the brain via blood vessels, which deliver a form of sugar called glucose, the researchers measured the cross-sectional area of the bony canals that enclose the cranial arteries.

By coupling these measurements with previously published estimates of brain glucose uptake and internal skull volume as an indicator of brain size, they examined seven species, including mice, rats, squirrels, rabbits, monkeys and humans. The researchers were able to show that larger canals enclose arteries that deliver more blood, and thus glucose, to the brain.

Then, using a statistical technique called multiple regression, they calculated brain glucose uptake for an additional 15 species for which brain costs were unknown, including lemurs, monkeys and treeshrews, primate relatives from Southeast Asia.

As expected, the researchers found that humans allot proportionally more energy to their brains than rodents, Old World monkeys, and great apes such as orangutans and chimpanzees.

Relative to resting metabolic rate -- the total amount of calories an animal burns each day just to keep breathing, digesting and staying warm -- the human brain demands more than twice as many calories as the chimpanzee brain, and at least three to five times more calories than the brains of squirrels, mice and rabbits.

But other animals have hungry brains too.

In terms of relative brain cost, there appears to be little difference between a human and a pen-tailed treeshrew, for example.

Even the ring-tailed lemur and the tiny quarter-pound pygmy marmoset, the world's smallest monkey, devote as much of their body energy to their brains as we do.

"This shouldn't come as too much of a surprise," Boyer said. "The metabolic cost of a structure like the brain is mainly dependent on how big it is, and many animals have bigger brain-to-body mass ratios than humans."

The results suggest that the ability to grow a relatively more expensive brain evolved not at the dawn of humans, but millions of years before, when our primate ancestors and their close relatives split from the branch of the mammal family tree that includes rodents and rabbits, Harrington said.

Previous studies calculated the amount of energy needed to fuel a brain based on neuron counts. But because the current study's method for estimating energy use relies on measurements of bone, rather than soft tissue such as neurons, it is now possible to estimate brain energy demand from the fossilized remains of animals that are extinct too, including early human ancestors.

"All you would need to take the measurements is an intact skull and some of the neck vertebrae," Harrington said.

Read more at Science Daily

How life arose from primordial muck: Experimental evidence overturns accepted theory

In the beginning, there were chemicals.

Life on Earth originated in an intimate partnership between the nucleic acids (genetic instructions for all organisms) and small proteins called peptides, according to two new papers from biochemists and biologists at the University of North Carolina at Chapel Hill and the University of Auckland. Their "peptide-RNA" hypothesis contradicts the widely-held "RNA-world" hypothesis, which states that life originated from nucleic acids and only later evolved to include proteins.

The new papers -- one in Molecular Biology and Evolution, the other in Biosystems -- show how recent experimental studies of two enzyme superfamilies surmount the tough theoretical questions about how complex life emerged on Earth more than four billion years ago.

"Until now, it has been thought to be impossible to conduct experiments to penetrate the origins of genetics," said co-author Charles Carter, PhD, professor of biochemistry and biophysics at the UNC School of Medicine. "But we have now shown that experimental results mesh beautifully with the 'peptide-RNA' theory, and so these experiments provide quite compelling answers to what happened at the beginning of life on Earth."

The special attributes of the ancestral versions of these enzyme superfamlies, and the self-reinforcing feedback system they would have formed with the first genes and proteins, would have kick-started early biology and driven the first life forms toward greater diversity and complexity, the researchers said.

Co-author Peter Wills, PhD, professor of physics at the University of Auckland, said, "Compared to the RNA-world hypothesis, what we've outlined is simply a much more probable scenario for the origin of life. We hope our data and the theory we've outlined in these papers will stimulate discussion and further research on questions relevant to the origins of life."

The two scientists are fully aware that the RNA-world hypothesis still dominates the origin-of-life research field. "That theory is so alluring and expedient that most people just don't think there's any alternative," Carter said. "But we are very confident there is."

Before there was life on Earth, there were simple chemicals. Somehow, they produced both amino acids and nucleotides that eventually became the proteins and nucleic acids necessary to create single cells. And the single cells became plants and animals. Research this century has revealed how the primordial chemical soup created the building blocks of life. There is also widespread scientific consensus on the historical path by which cells evolved into plants and animals.

But it's still a mystery how the amino acid building blocks were first assembled according to coded nucleic acid templates into the proteins that formed the machinery of all cells.

The widely accepted RNA-world theory posits that RNA -- the molecule that today plays roles in coding, regulating, and expressing genes -- elevated itself from the primordial soup of amino acids and cosmic chemicals, eventually to give rise first to short proteins called peptides and then to single-celled organisms.

Carter and Wills argue that RNA could not kick-start this process alone because it lacks a property they call "reflexivity." It cannot enforce the rules by which it is made. RNA needed peptides to form the reflexive feedback loop necessary to lead eventually to life forms.

At the heart of the peptide-RNA theory are enzymes so ancient and important that their remnants are still found in all living cells and even in some sub-cellular structures, including mitochondria and viruses. There are 20 of these ancient enzymes called aminoacyl-tRNA synthetases (aaRSs).

Each of them recognizes one of the 20 amino acids that serve as the building blocks of proteins. (Proteins, considered the machines of life, catalyze and synchronize the chemical reactions inside cells.) In modern organisms, an aaRS effectively links its assigned amino acid to an RNA string containing three nucleotides complementary to a similar string in the transcribed gene. The aaRSs thus play a central role in converting genes into proteins, a process called translation that is essential for all life forms.

The 20 aaRS enzymes belong to two structurally distinct families, each with 10 aaRSs. Carter's recent experimental studies showed that the two small enzyme ancestors of these two families were encoded by opposite, complementary strands of the same small gene. The simplicity of this arrangement, with its initial binary code of just two kinds of amino acids, suggests it occurred at the very dawn of biology. Moreover, the tight, yin-yang interdependence of these two related but highly distinct enzymes would have stabilized early biology in a way that made inevitable the orderly diversification of life that followed.

"These interdependent peptides and the nucleic acids encoding them would have been able to assist each other's molecular self-organization despite the continual random disruptions that beset all molecular processes," Carter said. "We believe that this is what gave rise to a peptide-RNA world early in Earth's history," Carter said.

Related research by Carter and UNC colleague Richard Wolfenden, PhD, previously revealed how the intimate chemistries of amino acids enabled the first aaRS enzymes to fold properly into functional enzymes, while simultaneously determining the assignments in the universal genetic coding table.

"The enforcement of the relationship between genes and amino acids depends on aaRSs, which are themselves encoded by genes and made of amino acids," Wills said. "The aaRSs, in turn, depend on that same relationship. There is a basic reflexivity at work here. Theorist Douglas Hofstadter called it a 'strange loop.' We propose that this, too, played a crucial role in the self-organization of biology when life began on Earth. Hofstadter argued that reflexivity furnishes the force driving the growth of complexity."

Carter and Wills developed two additional reasons why a pure RNA biology of any significance was unlikely to have predated a peptide-RNA biology. One reason is catalysis -- the acceleration of chemical reactions involving other molecules.

Catalysis is a key feature of biology that RNA cannot perform with much versatility. In particular, RNA enzymes cannot readily adjust their activities to temperature changes likely to have happened as the earth cooled, and so cannot perform the very broad range of catalytic accelerations that would have been necessary to synchronize the biochemistry of early cell-based life forms. Only peptide or protein enzymes have that kind of catalytic versatility, Carter said.

Secondly, Wills has shown that impossible obstacles would have blocked any transition from a pure-RNA world to a protein-RNA world and onward toward life.

"Such a rise from RNA to cell-based life would have required an out-of-the-blue appearance of an aaRS-like protein that worked even better than its adapted RNA counterpart," Carter said. "That extremely unlikely event would have needed to happen not just once but multiple times -- once for every amino acid in the existing gene-protein code. It just doesn't make sense."

Read more at Science Daily

Stem Cells From Young Donors Could Combat Frailty in Old Age

Picture two 80-year-old women. One is confined to a wheelchair, physically weak, and wholly dependent on her family for buying food, getting around, and managing her finances. The second 80-year-old plays tennis every day and drives her own car. She’s physically active, mentally sharp, and 100-percent independent.

So what’s going on here? Both women have the same number of candles on their birthday cake, but they seem to be aging at different rates. The culprit, physicians say, is a condition called frailty that affects roughly 10 percent of all people over 60. Frailty is characterized by decreased physical function and immune response with age, but also cognitive loss and increasing dependence on others for daily tasks.

The good news is that while aging is inevitable, frailty can be staved off. The standard treatment regimens for frailty are exercise, better nutrition, and prescription drug management. But researchers from the University of Miami believe they may have found another solution: stem cells. In two separate trials, groups of people in their 70s suffering from moderate to severe frailty were injected with hundreds of millions of stem cells from young healthy donors. And the initial results were promising.

Dr. Joshua Hare is a professor of medicine and director of the Interdisciplinary Stem Cell Institute at the University of Miami, where he conducted both of the stem cell-frailty trials. Participants were run through a battery of physical and cognitive tests six months after receiving stem cell treatments, including a six-minute walking test on a treadmill.

“One of the most striking findings was the walk distance,” Hare told Seeker. “It was up about 60 to 70 meters, which is close to the length of a football field. That’s a big increase in walk distance in six minutes for a person who’s slowing down. That kind of difference can make a meaningful change in a person’s day-to-day experience.”

It’s been proven that all humans lose stem cells as we age. These adult stem cells reside in “niches” in our organs and bone marrow, and are responsible for replenishing dead cells and growing new ones. We need stem cells to grow hair, maintain organs, and heal wounds. All of this slows down as we age and our stem cell reserves are depleted.

But there’s one type of adult stem cell that serves as a “master regulator” of all other stem cells, Hare explained. Mesenchymal stem cells, which are found all over the body, including the lining of blood vessels, orchestrate the replenishing activity in tissue, organs, and bone marrow. Hare’s hypothesis was that by boosting the supply of these master stem cells in older people, it could replenish stem cells across the body and combat the symptoms of frailty.

Hare and his team started with bone marrow donations from healthy young individuals, extracted the mesenchymal stem cells, and then grew them out in a specialized on-campus lab. In the Phase I trial, the main goal was to prove that injecting subjects with mesenchymal stem cells was safe at various doses, from 50 million to 200 million individual cells.

For the 15 individuals who participated in Phase I, there were no negative immune responses or serious health effects (Okay, one subject passed away, but it was from unrelated causes).

As for positive outcomes, participants who received doses of the 100 million and 200 million stem cells experienced a 50 percent reduction in levels of an inflammatory biomarker called TNF-α, a signaling protein that’s been linked to mitochondrial dysfunction and disruption of organ systems. Lower levels of TNF-α means less inflammation, which is believed to be a driver of frailty.

The Phase II stem cell trial recruited more participants (30 people with frailty) and was a double-blind placebo-controlled study. Again, there were no negative health effects of the treatment, and participants receiving the 100 million stem cell dose showed the most physical and cognitive improvements. Inflammatory markers were down, quality-of-life scores were up, and there was even evidence that stem cell therapy strengthened immune response to infections, which usually weakens with aging.

Hare was quick to point out that while mesenchymal stem cells may be a promising treatment for frailty, the injections don’t represent a cure for aging.

“Anti-aging is a science fiction concept,” said Hare. “I don’t think we’re ever going to able to reverse aging. Frailty is aging at a faster rate. What I like about the frailty paradigm, it’s very biological, very definable, it’s very agreed upon. We’re all aging, and some people are aging in a negative way. This treatment could put them on a more positive trajectory.”

Read more at Seeker

New Discoveries Bring Hope to the Fight Against Antibiotic Resistance

Colonies of pathogenic MRSA bacteria on a blood agar plate.

Antibiotic resistance is a worldwide threat to human health and survival. Bacteria are changing in response to the extensive overuse of antibiotics in medicine and the livestock industry, rendering these medicines ineffective while endangering the people who need them most.

Antibiotics known as β-lactams — which include penicillins, cephalosporins, and carbapenems — are the most widely prescribed around the world, and are increasingly resisted by bacteria.

The World Health Organization recently placed bacteria that are resistant to cephalosporins and carbapenems on its global priority list of antibiotic-resistant pathogens, emphasizing the critical need for a way to combat this problem. After completing two recent studies, a team of UK scientists may be close to a solution.

The papers, published in the Journal of Antimicrobial Chemotherapy and in the journal Molecular Microbiology, detail the team’s discovery of two mechanisms associated with β-lactam antibiotic resistance. This allowed the researchers — a team of chemists from the University of Bristol, the University of Oxford, and the University of Leeds — to develop a promising method for reversing resistance in the most commonly prescribed antibiotics.

“Antibiotic resistance is a growing problem, directly causing the deaths of around 750,000 people globally each year,” Dr. Matthew Avison, reader in molecular bacteriology at the University of Bristol and senior author of both studies, told Seeker. “β-lactam antibiotics are the most commonly used class, about 60 percent of all prescriptions, and they are particularly important for serious infections of patients in hospitals.”

The use of β-lactam enzymes is one important mechanism that bacteria use to resist antibiotics, by using them to destroy the medication once it enters a cell. Avison’s team was searching for a β-lactam enzyme inhibitor that would protect antibiotics in the body, allowing them to effectively fight infection.

They examined two inhibitors, one known as avibactam that is already being used in clinical trials, and another that is a bicyclic boronate inhibitor. On their own, both inhibitors failed to protect the antibiotic, known as ceftazidime. When paired with another antibiotic called aztreonam, however, they both worked extremely well, killing some of the most resistant bacteria the lab has ever observed.

“This discovery adds significantly to what we already know about β-lactam inhibitors,” Avison said. “We’ve shown that different combinations of β-lactamase inhibitors and β-lactam antibiotics work better than others, and most importantly, we have identified the biological explanation of this difference. We hope it will give clinicians the confidence to use these combinations in the treatment of serious infections where all other antimicrobials have failed.”

Earlier this year, the combination of avibactam and aztreonam helped save the lives of two patients in the US. Each case involved antibiotic-resistant illnesses, and the novel combination of the β-lactamase inhibitor with the β-lactam antibiotic cleared the infections.

“This would only be used on very seriously ill patients in hospitals,” Avidon noted, “and so would only be given intravenously, usually via an infusion pump.”

Studies on β-lactamase enzymes continue to aid in the discovery of many more β-lactamase inhibitors, like the bicyclic boronate inhibitor that this study found to be effective. According to Avison, this is the first time in 10 years that scientists are hopeful about reversing β-lactam antibiotic resistance.

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