Wednesday, June 07, 2023

GEOLOGY


Scientists discover ‘lost world’ of early ancestors in billion-year-old rocks


Peer-Reviewed Publication

AUSTRALIAN NATIONAL UNIVERSITY

The Protosterol Biota 

IMAGE: ARTIST’S IMAGINATION OF TWO PRIMORDIAL EUKARYOTIC ORGANISMS OF THE ‘PROTOSTEROL BIOTA’ ON THE OCEAN FLOOR. BASED ON MOLECULAR FOSSILS, ORGANISMS OF THE PROTOSTEROL BIOTA LIVED IN THE OCEANS ABOUT 1.6 TO 1.0 BILLION YEARS AGO AND ARE OUR EARLIEST KNOWN ANCESTORS. ORCHESTRATED IN MIDJOURNEY BY TA 2023. view more 

CREDIT: CREDIT: ORCHESTRATED IN MIDJOURNEY BY TA 2023



The discovery of a “lost world” of ancient organisms that lived in Earth’s waterways at least 1.6 billion years ago could change our understanding of our earliest ancestors.  

Known as the ‘Protosterol Biota’, these microscopic creatures are part of a family of organisms called eukaryotes. Eukaryotes have a complex cell structure that includes mitochondria, known as the “powerhouse” of the cell, and a nucleus that acts as the “control and information centre”.  

Modern forms of eukaryotes that inhabit Earth today include fungi, plants, animals and single-celled organisms such as amoebae. Humans and all other nucleated creatures can trace their ancestral lineage back to the Last Eukaryotic Common Ancestor (LECA). LECA lived more than 1.2 billion years ago. 

The discovery of the Protosterol Biota, published in Nature, was made by researchers from The Australian National University (ANU). According to the researchers, these organisms could have been the first predators on Earth.  

These ancient creatures were abundant in marine ecosystems across the world and probably shaped ecosystems for much of Earth’s history. The researchers say the Protosterol Biota lived at least one billion years before any animal or plant emerged. 

“Molecular remains of the Protosterol Biota detected in 1.6-billion-year-old rocks appear to be the oldest remnants of our own lineage – they lived even before LECA. These ancient creatures were abundant in marine ecosystems across the world and probably shaped ecosystems for much of Earth’s history,” Dr Benjamin Nettersheim, who completed his PhD at ANU and is now based at the University of Bremen in Germany, said. 

“Modern forms of eukaryotes are so powerful and dominant today that researchers thought they should have conquered the ancient oceans on Earth more than a billion years ago. 

“Scientists have long searched for fossilised evidence of these early eukaryotes, but their physical remains are extremely scarce. Earth’s ancient oceans rather appeared to be largely a bacterial broth. 

“One of the greatest puzzles of early evolution scientists have been trying to answer is: why didn’t our highly capable eukaryotic ancestors come to dominate the world’s ancient waterways? Where were they hiding?  

“Our study flips this theory on its head. We show that the Protosterol Biota were hiding in plain sight and were in fact abundant in the world’s ancient oceans and lakes all along. Scientists just didn’t know how to look for them – until now.”  

Professor Jochen Brocks from ANU, who made the discovery with Dr Nettersheim, said the Protosterol Biota were certainly more complex than bacteria and presumably larger, although it’s unknown what they looked like. 

“We believe they may have been the first predators on Earth, hunting and devouring bacteria,” Professor Brocks said.  

According to Professor Brocks, these creatures thrived from about 1.6 billion years ago up until about 800 million years ago.  

The end of this period in Earth’s evolutionary timeline is known as the ‘Tonian Transformation’, when more advanced nucleated organisms, such as fungi and algae, started to flourish. But exactly when the Protosterol Biota went extinct is unknown. 

“The Tonian Transformation is one of the most profound ecological turning points in our planet’s history,” Professor Brocks said.  

“Just as the dinosaurs had to go extinct so that our mammal ancestors could become large and abundant, perhaps the Protosterol Biota had to disappear a billion years earlier to make space for modern eukaryotes.”  

To make the discovery, the researchers studied fossil fat molecules found inside a 1.6-billion-year-old rock that had formed at the bottom of the ocean near what is now Australia’s Northern Territory. The molecules possessed a primordial chemical structure that hinted at the existence of early complex creatures that evolved before LECA and had since gone extinct.  

“Without these molecules, we would never have known that the Protosterol Biota existed. Early oceans largely appeared to be a bacterial world, but our new discovery shows that this probably wasn’t the case,” Dr Nettersheim said.   

Professor Brocks said: “Scientists had overlooked these molecules for four decades because they do not conform to typical molecular search images.” 

“But once we knew what we were looking for, we discovered that dozens of other rocks, taken from billion-year-old waterways across the world, were also oozing with similar fossil molecules.” 

Dr Nettersheim completed the analysis as part of his PhD at ANU before accepting a position at the University of Bremen. This work involved scientists from Australia, France, Germany and the United States. 

Tectonics matter: USU geoscientists probe geochemistry, microbial diversity of Peruvian hot springs


Heather Upin, Dennis Newell report microbial community composition is distinctly different in two tectonic settings

Peer-Reviewed Publication

UTAH STATE UNIVERSITY

Obtaining Microbial Sample from Peru's Aguas Calientas Pinaya 

IMAGE: UTAH STATE UNIVERSITY GEOSCIENTIST HEATHER UPIN COLLECTS A MICROBIAL SAMPLE FROM AGUAS CALIENTAS PINAYA IN PERU’S SOUTHERN ANDES. SHE AND USU COLLEAGUE DENNIS NEWELL PUBLISHED FINDINGS ABOUT MICROBIAL DIVERSITY IN PERUVIAN HOT SPRINGS. view more 

CREDIT: USU/DENNIS NEWELL



LOGAN, UTAH, USA -- South America’s Andes Mountains, the world’s longest mountain range and home to some of the planet’s highest peaks, feature thousands of hot springs. Driven by plate tectonics and fueled by hot rock and fluids, these thermal discharges vary widely in geochemistry and microbial diversity.

Utah State University geoscientists, along with colleagues from Montana State University, examined 14 hot springs within the southern Andes in Peru and discovered microbial community composition is distinctly different in two tectonic settings. Dennis Newell, associate professor in USU’s Department of Geosciences, and recent USU graduate Heather Upin, MS 2020, report findings in the April 11 online issue of Nature’s Communications Earth & Environment. Their research is supported by the National Science Foundation and the Geological Society of America.

“We know tectonic processes control hot spring temperature and geochemistry, yet how this, in turn, shapes microbial community composition is poorly understood,” says Newell, USU Geosciences graduate director.

The scientists collected geochemical and 16S ribosomal RNA gene sequencing data from hot springs in regions with contrasting styles of subduction — flat-slab and back-arc — and noted similarities in pH but found differences in geochemistry and microbiology.

“Flat-slab hot springs were chemically heterogeneous, had modest surface temperatures and were dominated by members of the metabolically diverse phylum Proteobacteria,” Newell says.

In contrast, the back-arc hot springs were more geochemically homogenous, had hotter water, exhibited high concentrations of dissolved metals and gases, and were home to heat-loving archaeal and bacterial organisms.

“These results tell us tectonics matter when it comes microbial community make-up, but little research has been conducted around the world to demonstrate this,” Newell says.

Further investigation, with efficient genomic research, at sites around the globe could reveal how microbes have evolved in tectonically diverse environments, he says.

Bubble, bubble, more earthquake trouble? Geoscientists study Alaska's Denali fault


Utah State University, University of Alaska Fairbanks researchers investigate fault system's mantle-to-crust connections

Peer-Reviewed Publication

UTAH STATE UNIVERSITY

Collecting Sample from Spring along Cantwell Segment of Alaska's Denali Fault 

IMAGE: UTAH STATE UNIVERSITY GEOCHEMIST DENNIS NEWELL COLLECTS DATA FROM A SPRING ALONG THE CANTWELL SEGMENT OF ALASKA’S DENALI FAULT. HE AND COLLEAGUES PUBLISHED FINDINGS IN THE JOURNAL ‘GEOLOGY,’ CITING EVIDENCE OF MANTLE-TO-CRUST CONNECTIONS THAT INCREASE THE POSSIBILITY OF A FUTURE MAJOR EARTHQUAKE. view more 

CREDIT: JEFF BENOWITZ




LOGAN, UTAH, USA -- The 1,200-mile-long Denali Fault stretches in an upward arc from southwestern Alaska and the Bering Sea eastward to western Canada’s Yukon Territory and British Columbia. The long-lived and active strike-slip fault system, which slices through Denali National Park and Preserve, is responsible for the formation of the Alaska Range.

“It’s a big, sweeping fault and the source of a magnitude 7.9 earthquake in 2002, that ruptured more than 200 miles of the Denali Fault, along with the Totschunda Fault to the east, causing significant damage to remote villages and central Alaska’s infrastructure,” says Utah State University geochemist Dennis Newell.

Understanding the restless fault’s mantle-to-crust connections provides critical information for understanding the lithospheric-scale fault’s seismic cycle, says Newell, associate professor in USU’s Department of Geosciences. He and colleagues Jeff Benowitz, an Alaska-based geochronologist, Sean Regan of the University of Alaska Fairbanks, and doctoral candidate Coleman Hiett of USU, collected and analyzed helium and carbon isotopic data from springs along a nearly 250-mile segment of the fault and published their findings, “Roadblocks and Speed Limits: Mantle-to-Surface Volatile Flux in the Lithospheric Scale Denali Fault, Alaska,” in the June 1, 2023 print issue of the journal Geology.

The research was funded by a one-year National Science Foundation Early-Concept Grant for Exploratory Research (EAGER) awarded to Newell and Regan in 2020.

“Active strike-slip faults like Denali have three-dimensional geometries with possible deep conduit connections below the Earth’s surface,” Newell says. “But we don’t know much about how and if these connections are maintained.”

To examine these possible deep connections, Newell and Regan sampled 12 springs along the Denali and Totschunda Faults, by way of helicopter and on foot, to the remote, mountainous regions of Alaska’s interior.

“Helium-3, a rare isotope of helium gas, in springs is a good indicator of whether or not an area has a connection to the Earth’s mantle,” Newell says. “Warm, bubbling springs west of the 2002 earthquake rupture, along the Cantwell segment of the Denali Fault, have a strong helium-3 signature, indicating intact connections to the mantle. In contrast, springs along the ruptured fault segment only have atmospheric gases, suggesting a ‘roadblock’ preventing the flow of mantle helium to the surface.”

These observations, he says, have implications for how groundwater pathways along the fault are changed by earthquakes, and the timescales on which they heal.

“The last major earthquake on the Cantwell segment was 400 years ago, and the helium data suggest those mantel connections have been reestablished,” Newell says. “These bubbling springs are indicative of the possibility of a future large destructive earthquake along the Denali Fault segment near Denali National Park, which receives some 600,000 visitors each summer.”

The geoscientists also seek data on how fast helium can move from the mantle to the crust along active faults.

“That’s the ‘speed limit’ part of our research,” Newell says. “This is important as it reveals mantle-to-surface volatile flux and how fluid pressure gradients may impact fault strength and seismicity along the fault.”

The fault’s mantle fluid flow rates fall in the range observed for the world’s other major and active strike-slip faults that form plate boundaries, he says, including California’s San Andreas Fault and Turkey’s North Anatolian Fault Zone. These types of faults host large, devastating earthquakes, such as February 2023’s deadly earthquake on the East Anatolia Fault, which caused widespread destruction in Turkey and Syria.

“Quantifying crust-to-mantle connections along major strike-slip faults is critical for understanding linkages between deep fluid flow, seismicity and fault healing,” Newell says.

SOCIOBIOLOGY

A pair of brain regions prompts females to kill or care for their young

Peer-Reviewed Publication

NYU LANGONE HEALTH / NYU GROSSMAN SCHOOL OF MEDICINE



A middle-brain region tied to the control of emotions likely prompts females to kill their young, a new study in mice shows. With the region also present in humans, the study authors say the findings could play a similar role in better understanding infanticide by women.

Before giving birth for the first time, female mice are known to often kill others’ pups. This behavior may have evolved to preserve scarce food supplies for their own future offspring, according to experts. However, most studies have focused on infanticide by adult males, and the brain mechanism behind this behavior in females has until now remained poorly understood.

Led by researchers at NYU Grossman School of Medicine, the study showed that chemically blocking the region, called the principal nucleus of the bed nucleus of stria terminalis (BNSTpr), prevented infanticide nearly 100% of the time. By contrast, when the study team artificially activated the brain region, both mothers and females without offspring killed pups in nearly all trials, attacking within a second of the stimulation. The mice rarely attacked other adults, the authors say, suggesting that the structure specifically controls aggression toward young animals.

The investigation also revealed that the BNSTpr appears to work in opposition to a brain region called the medial preoptic area (MPOA), itself known to promote mothering behavior. According to the findings, mice that had not yet reached motherhood showed high BNSTpr activity, which dampened activity in the MPOA. After the mice gave birth, however, MPOA activity ramped up, likely suppressing the infanticidal system in the process. The new mothers tended to avoid infanticide regardless of whether the pup was theirs.

“Our investigation pinpoints for the first time the brain mechanisms that we believe encourage and discourage infanticide in females,” said study lead author Long Mei, PhD, a Leon Levy Foundation postdoctoral fellow in NYU Langone Health’s Neuroscience Institute.

The new study, publishing online June 7 in the journal Nature, also demonstrates that the switch to maternal behaviors can be reversed by extra pressure to the BNSTpr, notes Mei.

According to the U.S. Centers for Disease Control and Prevention, child abuse is the fourth leading cause of death among preschool children in the United States. Mei notes that while early studies had largely focused on potential problems in the parenting centers of the brain, experts have more recently begun to search for a separate system dedicated to infanticide and aggression against children.

For the investigation, researchers first narrowed down the most likely brain regions behind infanticidal behavior by tracking which structures were connected to the MPOA. Next, they artificially stimulated each of the resulting seven areas in live mice to determine which, if any, caused the animals to attack pups. Then, the team blocked activity in the BNSTpr, the most promising candidate remaining, to see if this would prevent infanticide.

To demonstrate that the BNSTpr and MPOA counteract each other, the study authors prepared brain slices from female rodents and activated one region while at the same time recording cell activity in the other. They also traced how activity in these structures changed as rodents reached motherhood.

“Since these two connecting regions in the middle of the brain can be found in both rodents and humans alike, our findings hint at a possible target for understanding, and perhaps even treating, mothers who abuse their children,” said study senior author and neuroscientist Dayu Lin, PhD. “Maybe these cells normally remain dormant, but stress, postpartum depression, and other known triggers for child abuse may prompt them to become more active,” added Lin, a professor in the Departments of Psychiatry and Neuroscience and Physiology at NYU Langone.

That said, Lin, also a member of NYU Langone’s Neuroscience Institute, cautions that it remains unclear if the two brain regions perform the same roles in humans as they do in rodents.

She adds that the study team next plans to examine the BNSTpr and MPOA in male mice and to explore ways of turning off activity in the former region without invasive surgery.

Funding for the study was provided by National Institutes of Health grants R01HD092596, R21HD090563, R01MH101377, and U19NS107616. Additional funding was provided by the Leon Levy Foundation.

In addition to Mei and Lin, other NYU study investigators involved in the study were Rongzhen Yan, PhD; Luping Yin, PhD; and Regina Sullivan, PhD.


Columbia scientists discover that water molecules define the materials around us

A new paper argues that materials like wood, bacteria, and fungi belong to a newly identified class of matter, "hydration solids."

Peer-Reviewed Publication

COLUMBIA UNIVERSITY

Spirit Island, Jasper National Park, Canada 

IMAGE: SPIRIT ISLAND, JASPER NATIONAL PARK, CANADA. “WHEN WE TAKE A WALK IN THE WOODS, WE THINK OF THE TREES AND PLANTS AROUND US AS TYPICAL SOLIDS," PROFESSOR OZGUR SAHIN SAID. "THIS RESEARCH SHOWS THAT WE SHOULD REALLY THINK OF THOSE TREES AND PLANTS AS TOWERS OF WATER HOLDING SUGARS AND PROTEINS IN PLACE." view more 

CREDIT: PHOTO CREDIT: TERRY OTT



For decades, the fields of physics and chemistry have maintained that the atoms and molecules that make up the natural world define the character of solid matter. Salt crystals get their crystalline quality from the ionic bond between sodium and chloride ions, metals like iron or copper get their strength from the metallic bonds between iron or copper atoms, and rubbers get their stretchiness from the flexible bonds within polymers that constitute the rubber. The same principle applies for materials like fungi, bacteria, and wood.

Or so the story goes.

A new paper published today in Nature upends that paradigm, and argues that the character of many biological materials is actually created by the water that permeates these materials. Water gives rise to a solid and goes on to define the properties of that solid, all the while maintaining its liquid characteristics. In their paper, the authors group these and other materials into a new class of matter that they call “hydration solids,” which they say “acquire their structural rigidity, the defining characteristic of the solid state, from the fluid permeating their pores.” The new understanding of biological matter can help answer questions that have dogged scientists for years.

“I think this is a really special moment in science,” Ozgur Sahin, a professor of Biological Sciences and Physics and one of the paper’s authors, said. “It’s unifying something incredibly diverse and complex with a simple explanation. It’s a big surprise, an intellectual delight.”

Steven G. Harrellson, who recently completed doctoral studies in Columbia’s physics department, and is an author on the study, used the metaphor of a building to describe the team’s finding: “If you think of biological materials like a skyscraper, the molecular building blocks are the steel frames that hold them up, and water in between the molecular building blocks is the air inside the steel frames. We discovered that some skyscrapers aren’t supported by their steel frames, but by the air within those frames.”

“This idea may seem hard to believe, but it resolves mysteries and helps predict the existence of exciting phenomena in materials,” Sahin added.

When water is in its liquid form, its molecules strike a fine balance between order and disorder. But when the molecules that form biological materials combine with water, they tip the balance toward order: Water wants to return to its original state. As a result, the water molecules push the biological matter’s molecules away. That pushing force, called the hydration force, was identified in the 1970s, but its impact on biological matter was thought to be limited. This new paper’s argument that the hydration force is what defines the character of biological matter almost entirely, including how soft or hard it is, thus comes as a surprise.

We have long known that biological materials absorb ambient moisture. Think, for example, of a wooden door, that expands during a humid spell. This research, however, shows that that ambient water is much more central to wood, fungi, plants, and other natural materials’ character than we had ever known.

The team found that bringing water to the front and center allowed them to describe the characteristics that familiar organic materials display with very simple math. Previous models of how water interacts with organic matter have required advanced computer simulations to predict the properties of the material. The simplicity of the formulas that the team found can predict these properties suggests that they’re onto something.

To take one example, the team found that the simple equation E=Al/λ neatly describes how a material’s elasticity changes based on factors including humidity, temperature, and molecule size. (in this equation refers to the elasticity of a material; A is a factor that depends on the temperature and humidity of the environment; is the approximate size of biological molecules and λ is the distance over which hydration forces lose their strength).

“The more we worked on this project, the simpler the answers became,” Harrellson said, adding that the experience “is very rare in science.”

The new findings emerged from Professor Sahin’s ongoing research into the strange behavior of spores, dormant bacterial cells. For years, Sahin and his students have studied spores to understand why they expand forcefully when water is added to them and contract when water is removed. (Several years ago, Sahin and colleagues garnered media coverage for harnessing that capability to create small engine-like contraptions powered by spores.)

Around 2012, Sahin decided to take a step back to ask why the spores behave the way they do. He was joined by researchers Michael S. DeLay and Xi Chen, authors on the new paper, who were then members of his lab. Their experiments did not provide a resolution to the mysterious behavior of spores. “We ended up with more mysteries than when we started,” Sahin remembers. They were stuck, but the mysteries they encountered were hinting that there was something worth pursuing.

After years of pondering potential explanations, it occurred to Sahin that the mysteries the team continually encountered could be explained if the hydration force governed the way that water moved in spores.

The team had to do more experiments to test the idea. In 2018, Harrellson, who is now a software engineer at the data analytics firm Palantir, joined the project.

“When we initially tackled the project, it seemed impossibly complicated. We were trying to explain several different effects, each with their own unsatisfying formula. Once we started using hydration forces, every one of the old formulas could be stripped away. When only hydration forces were left, it felt like our feet finally hit the ground. It was amazing, and a huge relief; things made sense,” he said.

The results of those experiments led the team and their collaborators to this paper. In addition to Harrellson, DeLay, Chen, and Sahin, the paper’s other authors are Ahmet-Hamdi Cavusoglu, Jonathan Dworkin, and Howard A. Stone. Adam Driks of Loyola University Chicago, who also contributed research, passed away before the completion of the work. Funding for the research was provided by the U.S. Department of Energy’s Office of Science and Basic Energy Sciences; by the Office of Naval Research; by the National Institutes of Health; and by the David and Lucile Packard Fellows Program.

The paper’s findings apply to huge amounts of the world around us: Hygroscopic biological materials–that is, biological materials that allow water in and out of them–potentially make up anywhere from 50% to 90% of the living world around us, including all of the world’s wood, but also other familiar materials like bamboo, cotton, pine cones, wool, hair, fingernails, pollen grains in plants, the outer skin of animals, and bacterial and fungal spores that help these organisms survive and reproduce.

The term coined in the paper, “hydration solids,” applies to any natural material that’s responsive to the ambient humidity around it. With the equations that the team identified, they and other researchers can now predict materials’ mechanical properties from basic physics principles. So far that was true mainly of gases, thanks to the well-known general gas equation, which has been known to scientists since the 19th century.

“When we take a walk in the woods, we think of the trees and plants around us as typical solids. This research shows that we should really think of those trees and plants as towers of water holding sugars and proteins in place,” Sahin said: “It’s really water’s world.”

CSHL harnesses biology’s favorite chemical

Peer-Reviewed Publication

COLD SPRING HARBOR LABORATORY

Shoujun Sun in Moses lab 

IMAGE: SHOUJUN SUN, SEEN HERE, IS A POSTDOCTORAL FELLOW IN COLD SPRING HARBOR LABORATORY PROFESSOR JOHN MOSES’ LAB. SUN LED A NEW MOSES LAB STUDY THAT MARKS A SIGNIFICANT BREAKTHROUGH FOR THE FIELD OF CLICK CHEMISTRY. view more 

CREDIT: MOSES LAB/COLD SPRING HARBOR LABORATORY



For chemists like Cold Spring Harbor Laboratory (CSHL) Professor John Moses, diversity is a gateway to discovery. The more molecules scientists have to explore, the more likely it is they will find something useful. With the latest advancement from Moses’ lab, they can now quickly assemble a vast array of complex molecules. Among those molecules, Moses hopes to find effective new cancer therapeutics.

In collaboration with two-time Nobel laureate K. Barry Sharpless, Moses’ lab has devised a chemical transformation they call phosphorus fluoride exchange, or PFEx. PFEx efficiently snaps together chemical building blocks to form new molecules, in a reliable process known as click chemistry. Click chemistry already offers chemists a powerful set of tools. As the newest addition to that tool kit, PFEx takes a cue from biology and uses phosphorous as a chemical connector.

Inside cells, phosphorous gives structure to DNA and holds together essential energy-storing molecules. It’s a versatile connector. It can readily connect multiple chemical groups. These groups can be arranged around the phosphorous hub to create three-dimensional shapes.

Moses says: “Nature has recognized its importance—it’s a privileged group. If we’re trying to make drugs that interact with biology, we should not ignore that fact.”

Chemists can now use PFEx to click together multiple different chemical components around a single phosphorous hub. By incorporating more phosphorous connectors, they can build even more complex molecules. “We’re now decorating this three-dimensional linkage. And that’s going to allow us to access some new chemical space,” says CSHL Research Investigator Joshua Homer. “When you access new space, you’re accessing new function.”

PFEx reactions might even enable drugs to latch onto their targets inside the body. Moses’ team has already begun exploring PFEx as a source of cancer therapeutics. One benefit to this approach is that researchers can optimize the reactivity of the molecules involved in PFEx reactions. This could ensure potential drugs interact only with their desired targets, reducing the risk of side effects.

The researchers expect their new kind of click chemistry will help create materials with useful properties. For example, PFEx might be used to incorporate flame retardants or antimicrobials into new surfaces. Moses says PFEx materials will have an important advantage over the “forever chemicals” found in many of today’s products. Phosphorous bonds are not excessively stable. This means they can be easily broken down when a product is ready for recycling.

  

The power and potential of PFEx-based chemistry lie in its ability to rapidly and reliably click together complex molecules using sustainable lab science. The illustration above shows how PFEx is compatible with other click chemistry bonds, including the 2022 Nobel prize-winning CuAAC reactions.

CREDIT

Moses lab/Cold Spring Harbor Laboratory