Thursday, July 18, 2019

Maternal Secrets from 3 Million B.C.E.



A stunning new research result published in Nature reveals for the first time the breastfeeding and weaning habits of an early human ancestor that lived between 3 and 2 million years ago in South Africa.

Credit: La Trobe University

As part of an international research team – led by Southern Cross University and Monash University – Professor Andy Herries, Head of La Trobe University’s Archaeology and History Department, helped analyse more than two-million-year-old teeth from Australopithecus africanus fossils found in South Africa.

The research team revealed that infants were breastfed continuously from birth to about one year of age. In addition, the study has shown nursing appears to have continued in a cyclical pattern in the early years for infants, as seasonal changes and food shortages caused the mother to supplement gathered foods with breastmilk.

“For the first time, we gained new insight into the way our ancestors raised their young, and how mothers had to supplement solid food intake with breastmilk when resources were scarce,” said geochemist Dr Joannes-Boyau from the Geoarchaeology and Archaeometry Research Group (GARG) at Southern Cross University.

“Australopithecus africanus was the first human species to inhabit what was likely a relatively harsh limestone landscape in South Africa. This research potentially shows that living in these environments was difficult for our early ancestors, particularly as climate began to change around 2.3 to 2 million years ago and this may have led to their ultimate extinction not long after this time,” said Professor Andy Herries, Head of La Trobe University’s Archaeology and History Department.

“These finds suggest for the first time the existence of a long-lasting mother-infant bond in Australopithecus. This makes us to rethink on the social organisations among our earliest ancestors,” said Dr Fiorenza, who is an expert in the evolution of human diet at the Monash Biomedicine Discovery Institute (BDI).

“Fundamentally, our discovery of a reliance by Australopithecus africanus mothers to provide nutritional supplementation for their offspring and use of fallback resources highlights the survival challenges that populations of early human ancestors faced in the past environments of South Africa,” said Dr Adams, an expert in hominin palaeoecology and South Africa sites at the Monash BDI.

For decades there has been speculation about how early ancestors raised their offspring. With this study, the research team has opened a new window into our enigmatic evolutionary history. Australopithecus africanus lived from about two to three million years ago during a period of major climatic and ecological change in South Africa, and the species was characterised by a combination of human-like and retained ape-like traits. While the first fossils of Australopithecus were found almost a century ago, scientists have only now been able to unlock the secrets of how they raised their young. 

Teeth grow similarly to trees; they form by adding layer after layer of enamel and dentine tissues every day. Thus, teeth are particularly valuable for reconstructing the biological events occurring during the early period of life of an individual, simply because they preserve precise temporal changes and chemical records of key elements incorporated in the food we eat. Specialized laser sampling techniques were used to vaporize microscopic portions on the surface of the tooth. The gas containing the sample is then analysed for chemical signatures with a mass spectrometer – enabling researchers to develop microscopic geochemical maps which can tell the story of the diet and health of an individual over time.

“We can tell from the repetitive bands that appear as the tooth developed that the fall back food was high in lithium, which is believed to be a mechanism to reduce protein deficiency in infants more prone to adverse effect during growth periods,” Dr Joannes-Boyau said.

“This likely reduced the potential number of offspring, because of the length of time infants relied on a supply of breastmilk. The strong bond between mothers and offspring for a number of years has implications for group dynamics, the social structure of the species, relationships between mother and infant and the priority that had to be placed on maintaining access to reliable food supplies,” he said.

“This finding underscores the diversity, variability and flexibility in habitats and adaptive strategies these australopiths used to obtain food, avoid predators, and raise their offspring,” Dr Adams emphasised.

“This is the first direct proof of maternal roles of one of our earliest ancestors and contributes to our understanding of the history of family dynamics and childhood,” concluded Dr Fiorenza.

Dr Joannes-Boyau conducted the analyses at the Geoarchaeology and Archaeometry Research Group at Southern Cross University in Lismore NSW and at the Icahn School of Medicine at Mount Sinai in New York. This work was conducted as part of an ARC Discovery Project led by Professor Herries at La Trobe University, looking at what drove changes in human species, and their diversity between 2.6 and 1.8 million years ago in South Africa.

The team will now work on species that have evolved after 2 million years, including the cave site of Drimolen where Professor Herries runs an international field school in Palaeoanthropology each June, to develop the first comprehensive record of how infants were raised throughout a critical time in our evolutionary history at the extinction of Australopithecus and the first occurrence of our genus, Homo.

Read the full paper in Nature titled Elemental signatures in Australopithecus africanus teeth reveal seasonal dietary stress.



Contacts and sources:
Claire BowersLa Trobe University






Crystalline ‘Artificial Muscle’ Makes Paper Doll Do Sit-Ups (Video)



Scary movies about dolls that can move, like Anabelle and Chucky, are popular at theaters this summer. Meanwhile, a much less menacing animated doll has chemists talking. Researchers have given a foil “paper doll” the ability to move and do sit-ups with a new material called polymer covalent organic frameworks (polyCOFs). They report their results in ACS Central Science. Watch a video of the material in action here.


Youtube ID: YLmqBmsnV3g

Scientists make conventional COFs by linking simple organic building blocks, such as carbon-containing molecules with boric acid or aldehyde groups, with covalent bonds. The ordered, porous structures show great potential for various applications, including catalysis, gas storage and drug delivery. However, COFs typically exist as nano- or micro-sized crystalline powders that are brittle and can’t be made into larger sheets or membranes that would be useful for many practical applications. Yao Chen, Shengqian Ma, Zhenjie Zhang and colleagues wondered if they could improve COFs’ mechanical properties by using linear polymers as building block

The researchers based their polyCOF on an existing COF structure, but during the compound’s synthesis, they added polyethylene glycol (PEG) to the reactants. The PEG chains bridged the pore space of the COF, making a more compact, cohesive and stable structure. In contrast to the original COF, the polyCOF could be incorporated into flexible membranes that were repeatedly bent, twisted or stretched without damage. 

To demonstrate how polyCOFs could be used as an artificial muscle, the team made a doll containing the membrane as the waist and aluminum foil as its other parts. Upon exposure to ethanol vapors, the doll sat up; when the vapors were withdrawn, it laid down. The researchers repeated these actions several times, making the doll do “sit-ups.” The expansion of polyCOF pores upon binding the gas likely explains the doll’s calisthenics, the researchers say.

The authors acknowledge funding from the National Natural Science Foundation of China, Tianjin Natural Science Foundation of China and the National Science Foundation.
Contacts and sources:



Citation:




Semi-Synthetic Bacteria Produce Exotic Proteins and Unnatural Amino Acids



Synthetic biologists seek to create new life with forms and functions not seen in nature.

 Although scientists are a long way from making a completely artificial life form, they have made semi-synthetic organisms that have an expanded genetic code, allowing them to produce never-before-seen proteins. 

Now, researchers reporting in Journal of the American Chemical Society have optimized a semi-synthetic bacteria to efficiently produce proteins containing unnatural amino acids.

Researchers identified this unnatural base pair as being optimal for information storage in a semi-synthetic organism.
Credit: Adapted from Journal of the American Chemical Society 2019, DOI: 10.1021/jacs.9b02075


All of Earth’s natural life forms store information using a four-letter genetic code consisting of the nucleotides deoxyadenosine (dA), deoxyguanosine (dG), deoxycytidine (dC), and deoxythymidine (dT). Within the DNA double helix, dA pairs with dT, and dG with dC, to form the “rungs” of the DNA ladder. 

Recently, researchers have made synthetic nucleotides that can pair up with each other. When they placed these unnatural nucleotides into genes, bacteria could replicate the DNA and convert the sequences into RNA and then proteins that contained unconventional amino acids. However, bacteria often cannot use these synthetic sequences as efficiently as the natural ones. Therefore, Lingjun Li, Floyd Romesberg and colleagues wanted to optimize the unnatural base pairs to improve protein production.

The researchers tested different combinations of unnatural base pairs in E. coli and observed which ones were replicated most efficiently and produced the highest levels of a protein. Some of the synthetic base pairs had been tested before, whereas others were new variations. The team then used these optimized base pairs to demonstrate, for the first time, a semi-synthetic organism that could make a protein containing multiple unnatural amino acids.

The authors acknowledge funding from the National Institutes of Health, the National Science Foundation,Boehringer Ingelheim Fonds, NASA Exobiology and Henan Normal University.

Contacts and sources:
American Chemical Society

Citation: Optimization of Replication, Transcription, and Translation in a Semi-Synthetic Organism.
Aaron W. Feldman, Vivian T. Dien, Rebekah J. Karadeema, Emil C. Fischer, Yanbo You, Brooke A. Anderson, Ramanarayanan Krishnamurthy, Jason S. Chen, Lingjun Li, Floyd E. Romesberg. Journal of the American Chemical Society, 2019; 141 (27): 10644 DOI: 10.1021/jacs.9b02075



Wednesday, July 17, 2019

Secrets of a Sex Changing Fish Revealed for the First Time



Do not take it for granted that the sex of an animal is established at birth and doesn’t change.

There are about 500 species of fish change sex in adulthood, often in response to environmental cues. How these fish change sex has, until now, been a mystery.
Credit: Kevin Bryant

The secrets of fish that biologically change sex have, for the first time, been revealed by an international collaboration led by New Zealand scientists and including La Trobe University geneticist and Prime Minister’s Prize for Science winner 2017, Professor Jenny Graves. The findings were published today in the prestigious journal, Science Advances.

“I’ve followed the bluehead wrasse for years because sex change is so quick and is triggered by a visual cue,” Professor Graves said.

“How sex can reverse so spectacularly has been a mystery for decades. The genes haven’t changed, so it must be the signals that turn them off and on.”

Bluehead wrasses live in groups, on coral reefs of the Caribbean. A dominant male - with a blue head - protects a harem of yellow females. If the male is removed, the biggest female becomes male – in just 10 days. She changes her behaviour in minutes, her colour in hours. Her ovary becomes a testis and by 10 days it is making sperm.

Using the latest genetic approaches - high-throughput RNA-sequencing and epigenetic analyses - the researchers discovered when and how specific genes are turned off and on in the brain and gonad so that sex change can occur.

The study is important for understanding how genes get turned off and on during development in all animals (including humans), and how the environment can influence this process.

“We found that sex change involves a complete genetic rewiring of the gonad,” Dr Erica Todd from the University of Otago, the co-lead author, said.

“Genes needed to maintain the ovary are first turned off, and then a new genetic pathway is steadily turned on to promote testis formation.”

Co-lead author PhD candidate Oscar Ortega-Recalde, also from the University of Otago, said the amazing transformation also appears possible through changes in cellular “memory”.

“Chemical markers on DNA control gene expression and to help cells remember their specific function in the body. Our study is important because it shows that sex change involves profound changes in these chemical marks,” Mr Ortega-Recalde said.

La Trobe’s Professor Jenny Graves said the project links to studies of sex reversal in Australian dragon lizards that she is collaborating on with researchers at the University of Canberra.

“With dragon lizards the trigger for sex change is temperature, which overrides genes on the male sex chromosomes and causes embryos to develop as females,” Professor Graves said.

“Sex reversal in dragons and the wrasse involve some of the same genes, so I think we are looking at an ancient system for environmental control of gene activity.”

The bluehead wrasse research is part of a highly collaborative project involving Professor Neil Gemmell, Dr Tim Hore (two graduates from Professor Graves’ lab) and others from the University of Otago’s Departments of Anatomy and Biochemistry, and researchers from North Carolina State University, USA.

The work was funded by the Royal Society of New Zealand Marsden Fund, the Rutherford Foundation, the University of Otago, and the National Science Foundation (USA).

More information, including a copy of the paper - Stress, novel sex genes, and epigenetic reprogramming orchestrate socially controlled sex change - can be found online at the Science Advances press package at https://advances.sciencemag.org/content/5/7/eaaw7006

ENDS

PHOTO:
Contacts and sources:
Claire Bowers
La Trobe University

Dr Erica Todd, Department of Anatomy,
University of Otago






‘Insect Armageddon’ and the Rise of Tyrant Ants



La Trobe University researchers have uncovered an exception to the global phenomenon known as ‘Insect Armageddon’ in the largest study of Australian insect populations conducted to date.


Credit: La Trobe University

Researchers studied ants in the Simpson Desert for 22 years and found that local changes in climate, such as long-term increases in rainfall, combined with human efforts to restore ecosystems, may have led to increased numbers of species – rather than the declines which might be expected in such unpredictable conditions.

Lead researcher, Associate Professor Heloise Gibb, said annual rainfall in the north Australian desert varied from 79 to 570 millimetres.

“While this unpredictability in rainfall is expected in hot climates, this is the first time we’ve been able to understand how insects respond to such large inconsistencies in their environment,” Associate Professor Gibb said.

“For many species, this unpredictability – exacerbated by climate change – would equate to increasingly difficult conditions for their survival.

“What we’ve found, however, in contrast to warnings of a long-term decline in insects, is that species that already like it hot may do better where it also becomes wetter.”

Associate Professor Gibb said researchers discovered a boom in the population of aggressive sugar-feeding ants with every rapid increase in rainfall.

“Water is the driving factor for this species’ survival,” Associate Professor Gibb said.

“These tyrant ants, as we would call them, are able to adjust their time of activity so they’re active only when above-ground conditions are suitable.

“While the average temperature of their environment may be increasing, their flexibility in tough environments enables them to survive until the next big rainfall.”

Researchers found the increase in ant populations reflected the change in resources available to them.

“Following rainfall, plants grow, flower and seed, providing honeydew, nectar and a food source for other invertebrates that the tyrant ants consume,” Associate Professor Gibb said.

While ants other than the tyrants – including furnace ants, mono ants, sugar ants and pony ants – didn’t respond as clearly in the study, their populations did increase over time.

Half way through the study, the property on which it was conducted was purchased by a conservation agency which stopped cattle grazing on the premises.

“While it’s difficult to explicitly link this management change with ant responses, we believe this change was also critical in driving ecosystem change that eventually improved conditions for ants, allowing them to boom in response to extreme rainfall events,” Associate Professor Gibb said.

“Active conservation efforts, funded by the public, can have very positive effects on biodiversity.

“It’s important that future research identifies the best approach and locations for these efforts to take place if we want to ensure the continued persistence of the vast diversity of life that this planet currently supports.”

The study has been published in the Journal of Animal Ecology and conducted in partnership with the University of Sydney.


Contacts and sources:
Claire Bowers
La Trobe University
Citation: Long‐term responses of desert ant assemblages to climate.
Heloise Gibb, Blair F. Grossman, Chris R. Dickman, Orsolya Decker, Glenda M. Wardle. Journal of Animal Ecology, 2019; DOI: 10.1111/1365-2656.13052




DNA Origami Joins Forces with Molecular Motors to Build Nanoscale Machines



Every year, robots get more and more life-like. Solar-powered bees fly on lithe wings, humanoids stick backflips, and teams of soccer bots strategize how to dribble, pass, and score. The more researchers discover about how living creatures move, the more machines can imitate them all the way down to their smallest molecules.

“We have these amazing machines already in our bodies, and they work so well,” said Pallav Kosuri. “We just don’t know exactly how they work.”

For decades, researchers have chased ways to study how biological machines power living things. Every mechanical movement—from contracting a muscle to replicating DNA—relies on molecular motors that take tiny, near-undetectable steps.

Hundreds even thousands of tiny DNA propellers will fit on a microscopic slide.

 Credit: Pallav Kosuri, Zhuang Lab

Trying to see them move is like trying to watch a soccer game taking place on the moon.

The Zhuang Lab attached fluorescent molecules (white) to the tip of a propeller made of DNA. When a molecular motor (blue) moves along the double-stranded DNA, it rotates the helix and the propellers, enabling the team to capture the motor's movement on camera.
 



 Credit: Pallav Kosuri, Zhuang Lab


Now, in a recent study published in Nature, a team of researchers including Xiaowei Zhuang, the David B. Arnold Professor of Science at Harvard University and a Howard Hughes Medical Institute Investigator, and Zhuang Lab postdoctoral scholar Pallav Kosuri and Benjamin Altheimer, a Ph.D. student in the Graduate School of Arts and Sciences, captured the first recorded rotational steps of a molecular motor as it moved from one DNA base pair to another.

In collaboration with Peng Yin, a professor at the Wyss Institute and Harvard Medical School, and his graduate student Mingjie Dai, the team combined DNA origami with high-precision single-molecule tracking, creating a new technique called ORBIT—origami-rotor-based imaging and tracking—to look at molecular machines in motion.

In our bodies, some molecular motors march straight across muscle cells, causing them to contract. Others repair, replicate or transcribe DNA: These DNA-interacting motors can grab onto a double-stranded helix and climb from one base to the next, like walking up a spiral staircase.

To see these mini machines in motion, the team sought to take advantage of this twisting movement. First, they glued the DNA-interacting motor to a rigid support. Once pinned, the motor had to rotate the helix to get from one base to the next. So, if they could measure how the helix rotated, they could determine how the motor moved.

But there was still one problem: Every time one motor moves across one base pair, the rotation shifts the DNA by a fraction of a nanometer. That shift is too small to resolve with even the most advanced light microscopes.

Two pens lying in the shape of helicopter propellers gave the team an idea: A propeller fastened to the spinning DNA would move at the same speed as the helix and, therefore, the molecular motor. If they could build a DNA helicopter large enough that the swinging rotor blades could be visualized, they could capture the motor’s elusive movement on camera.

To build molecule-sized propellers, Kosuri, Altheimer and Zhuang decided to try DNA origami. Used to create art, deliver drugs to cells, study the immune system, and more, DNA origami involves manipulating strands to bind into beautiful, complicated shapes outside the traditional double-helix.

“If you have two complementary strands of DNA, they zip up,” Kosuri said. “That’s what they do.” But, if one strand is altered to complement a strand in a different helix, they can find each other and zip up instead, weaving new structures.

For help constructing their propellers, the team enlisted Peng Yin, a pioneer of DNA origami technology. With guidance from Yin and his graduate student Dai, the team wove almost 200 individual pieces of DNA snippets into a propeller-like shape 160 nanometers in length. Then, they attached the blades to a regular double-helix and fed the other end to RecBCD, a molecular motor that unzips DNA. When the motor got to work, it spun the DNA, twisting the propellers like a corkscrew.

“No one had seen this protein actually rotate the DNA because it moves super-fast,” Kosuri said.

The motor can move across hundreds of bases in less than a second. But, with their origami propellers and a high-speed camera running at a thousand frames per second, the team could finally record the motor’s fast rotational movements.

“So many critical processes in the body involve interactions between proteins and DNA,” said Altheimer. Understanding how these proteins work—or fail to work—could help answer fundamental biological questions about human health and disease.

So, the team started to explore other types of DNA motors. One, RNA polymerase, moves along DNA to read and transcribe the genetic code into RNA. Inspired by previous research, the team theorized this motor might rotate DNA in 35-degree steps, corresponding to the angle between two neighboring nucleotide bases.

ORBIT proved them right: “For the first time, we’ve been able to see the single base pair rotations that underlie DNA transcription,” Kosuri said. Those rotational steps are, as predicted, around 35 degrees.

Millions of self-assembling DNA propellers can fit into just one microscope slide, which means the team can study hundreds or even thousands of them at once, using just one camera attached to one microscope. That way, they can compare and contrast how individual motors perform their work.

“There are no two enzymes that are identical,” Kosuri said. “It’s like a zoo.”

One motor protein might leap ahead while another momentarily scrambles backwards. Yet another might pause on one base for longer than any other. The team doesn’t yet know exactly why they move like they do. Armed with ORBIT, they soon might.

ORBIT could also inspire new nanotechnology designs powered with biological energy sources like ATP. “What we’ve made is a hybrid nanomachine that uses both designed components and natural biological motors,” Kosuri said.

One day, such hybrid technology could be the literal foundation for biologically-inspired robots.


Contacts and sources:
Caitlin McDermott-Murphy
Harvard University





Dodging 20,000 Near Earth Asteroids, 20 Minute Doomsday Window Opening for Large Asteroid 1950 DA

In the mid‑1990s scientists knew of less than 200 near‑Earth asteroids, but with better telescopes and more efforts at surveying, the numbers of known asteroids has grown astronomically. 

There are over 20,000 known near-Earth asteroids (NEAs), over a hundred short-period near-Earth comets (NECs), and a number of solar-orbiting spacecraft and meteoroids large enough to be tracked in space before striking the Earth.

Modeling the shape and movement of near‑Earth asteroids is now up to 25 times faster thanks to new Washington State University research.

The WSU scientists improved the software used to track thousands of near‑Earth asteroids and comets, which are defined as being within 121 million miles or about 1.3 times the distance to the sun.
Rendering of two asteroids in outer space with Earth in the distance.
Credit: WSU

Their work provides a valuable new tool for studying asteroids and determining which of them might be on a collision course with Earth.

Matt Engels, a PhD student who has been working with Professor Scott Hudson in the School of Engineering and Applied Sciences at WSU Tri‑Cities, is lead author of a paper on the research in the July issue of Astronomy and Computing.

Researchers would like to have better information on asteroids, including which of them might crash into earth. The rocks also can provide valuable scientific information, answering fundamental questions about the creation of our solar system and providing a glimpse into our planetary past. Knowing more about individual asteroid composition also could open up new opportunities for possible asteroid mining.

NASA maintains a catalog that includes information on more than 20,000 near‑earth asteroids and comets. In the mid‑1990s scientists knew of less than 200 of such outer space rocks, but with better telescopes and more efforts at surveying, the numbers of known asteroids has grown dramatically.

But, there are only a trickle of papers that describe individual asteroids. Once a new asteroid is discovered, modeling it takes several months, if not longer, said Engels. The research is painstaking.

In the mid‑1990s, Hudson, who has an asteroid named after him, wrote the primary modeling software tool that researchers use to describe asteroids and their behavior. Using ground-based radar and optics data, the software helps researchers learn important information, such as an asteroid’s possible mineral make-up, current and future orbit, shape, and how it spins in space. In fact, Hudson co-authored a paper published in Science that determined that at least one asteroid, 1950 DA, has a very tiny chance of hitting earth during a precise 20‑minute period in March of 2880.

“The software was written for a super computer, so it’s really, really slow,” said Engels, who jumped at improving it for his PhD project. “It can take a long time to do the modeling to draw any conclusions from it, and it takes awhile to crunch the data to write a paper in the first place.”

To check the accuracy of their computer model, the researchers compared their results to clay models of asteroids. The bottom right image comes from the computer model, and the bottom left is an image of the model asteroid.

Credit: WSU

The new version of code works much faster. The researchers revised it to make operations work concurrently instead of performing one at a time. Because the work is very similar to the everyday graphics that modern computers use to crunch out nice displays, the researchers transferred the operations to the computer’s graphics processing units, or GPUs. GPUs are designed to perform complex mathematical and geometric calculations for graphics rendering and have a tremendous amount of power to do parallel calculations.

“It’s taking advantage of the horsepower that is used in computer graphics rendering,” Engels said. “It’s very cost effective and you don’t need a super computer. You can use a consumer level graphics card available for under $500.”

The improvements to the algorithms could also someday be used for a variety of other purposes, said Engels, who works as a research engineer at Pacific Northwest National Laboratory, such as for modeling systems in the electric power grid or gas and oil industry.

Engels is verifying the code with real asteroid data. He hopes to have it available to the astronomy community later this year.

Contacts and sources:
Tina Hilding, Matthias Engels
Washington State University

Citation: GPU-accelerated algorithm for asteroid shape https://doi.org/10.1016/j.ascom.2019.05.003modeling https://www.sciencedirect.com/science/article/pii/S2213133718301379?via%3Dihub


1-in-7000 Chances Asteroid 2006 QV89 Strikes Earth September 9, 2019

Asteroid 2006 QV89, a small object 20 to 50 metres in diameter, was in the news lately because of a very small, 1-in-7000 chance of impact with Earth on 9 September 2019.

In the first known case of ruling out an asteroid impact through a ‘non-detection’, ESA and the European Southern Observatory have concluded that asteroid 2006 QV89 is not on a collision course this year – and the chance of any future impact is extremely remote.

Catching a glimpse

Asteroids come and go, quite literally, often frustrating astronomers. You can catch sight of a hurtling space rock, take some measurements to narrow down its orbit, and days later it's gone – potentially remaining unobservable for decades.

Orbit of asteroid 2006 QV89

Orbit of asteroid 2006 QV89

In general, when an asteroid is found to have even a tiny chance of impacting Earth, further observations and measurements are taken. These ‘astrometric’ data refine our understanding of the asteroid’s path, improving our understanding of the risk it poses and often excluding any chance of collision altogether.

However, the case of asteroid 2006 QV89 is peculiar. The object was discovered in August 2006 and then observed for only ten days. These observations suggested it had a 1-in-7000 chance of impacting Earth on 9 September 2019.

After the tenth day, the asteroid was unobservable and has not been seen since. Now, after more than a decade, we can predict its position with only very poor accuracy. As a result it is extremely difficult for astronomers to re-observe it, as no one knows exactly where to point a telescope.

Nevertheless, there is a way to obtain the information needed.

Nice to not see you

ESO's VLT Survey Telescope



While we do not know 2006 QV89’s trajectory exactly, we do know where it would appear in the sky if it were on a collision course with our planet. Therefore, we can simply observe this small area of the sky to check that the asteroid is indeed, hopefully, not there.

This way, we have the chance to indirectly exclude any risk of an impact, even without actually seeing the asteroid.

This is precisely what ESA and the European Southern Observatory (ESO) did on 4 and 5 July, as part of the ongoing collaboration between the two organisations to observe high-risk asteroids using ESO's Very Large Telescope (VLT).

Teams obtained very ‘deep’ images of a small area in the sky, where the asteroid would have been located if it were on track to impact Earth in September.

Nothing was seen.

The un-detection of asteroid 2006 QV18

The image shows the region of the sky where asteroid 2006 QV80 would have been seen if on a collision course with Earth this year.

Credit: ESA




The three red crosses reveal the specific locations, where the asteroid could have appeared as a single, bright, round source, had it been on a collision course.

Even if the asteroid were smaller than expected, at only a few metres across, it would have been seen in the image. Any smaller than this and the VLT could not have spotted it, but it would also be considered harmless as any asteroid this size would burn up in Earth’s atmosphere.

Planetary Defence at ESA

The Rosetta probe passed within 3,162 km (1,965 mi) of Lutetia, a larger asteroid, in July 2010.  It was the largest asteroid visited by a spacecraft until Dawn arrived at Vesta in July 2011
Credit: ESA

Visualization of Asteroid Itokawa: This artist’s impression, based on detailed spacecraft observations, shows the strange peanut-shaped asteroid Itokawa. By making exquisitely precise timing measurements using ESO’s New Technology Telescope a team of astronomers has found that different parts of this asteroid have different densities. As well as revealing secrets about the asteroid’s formation, finding out what lies below the surface of asteroids may also shed light on what happens when bodies collide in the Solar System, and provide clues about how planets form.
Credit: JAXA, ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org)

Find out more about ESA’s work to detect risky asteroids, and one day even to mitigate the risk they pose, here.

Learn all about the potentially hazardous asteroids in the solar system and ESA’s evolving risk list here, and stay up-to-date by signing up for the monthly asteroid newsletter.




Contacts and sources:










Citation:




Revealing the Milky Way Galactic Bar


The first direct measurement of the bar-shaped collection of stars at the centre of our Milky Way galaxy has been made by combining data from the Gaia mission (European Space Agency, ESA) with complementary observations by ground- and space-based telescopes.

 The study, published in Astronomy & Astrophysics, was led by researchers from the Institute of Science Cosmos of the University of Barcelona and from the Leibniz Institute for Astrophysics Potsdam (Germany).

This color chart, superimposed on an artistic representation of the galaxy, shows the distribution of 150 million stars in the Milky Way probed using data from the second release of ESA’s Gaia mission in combination with infrared and optical surveys, with orange/yellow hues indicating greater density of stars. Most of these stars are red giants. While the majority of charted stars are located closer to the Sun (the larger orange/yellow blob in the lower part of the image), a large and elongated feature populated by many stars is also visible in the central region of the galaxy: this is the first geometric indication of the galactic bar. 
This colour chart, superimposed on an artistic representation of the galaxy, shows the distribution of 150 million stars in the Milky Way probed using data from the second release of ESA’s Gaia mission in combination with infrared and optical surveys, with orange/yellow hues indicating greater density of stars. Most of these stars are red giants.  While the majority of charted stars are located closer to the Sun (the larger orange/yellow blob in the lower part of the image), a large and elongated feature populated by many stars is also visible in the central region of the galaxy: this is the first geometric indication of the galactic bar.  Credit: ESA/Gaia/DPAC, A. Khalatyan (AIP) & StarHorse Team; mapa artístic de la Galaxia: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)
Credit: ESA/Gaia/DPAC, A. Khalatyan (AIP) & StarHorse Team; mapa artístic de la Galaxia: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)
The second release of data from Gaia star-mapping satellite, published in 2018, has been revolutionize many fields of astronomy. The unprecedented catalogue contains the brightness, positions, distance indicators and motions across the sky for more than one billion stars in our Milky Way galaxy, along with information about other celestial bodies.

This is just the beginning. While the second release is based on the first twenty-two months of Gaia’s surveys, the satellite has been scanning the sky for five years, and will keep doing so at least until 2022. New data releases planned in coming years will steadily improve measurements as well as provide extra information that will enable us to chart our home galaxy and delve into its history like never before.

Meanwhile, a team of astronomers have combined the latest Gaia data with infrared and optical observations performed from ground and space to provide a preview of what future releases of ESA’s stellar surveyor will reveal.

“We looked in particular at two of the stellar parameters contained in the Gaia data: the surface temperature of stars and the ‘extinction’, which is basically a measure of how much dust there is between us and the stars, obscuring their light and making it appear redder,” says Friedrich Anders ICCUB member and lead author of the new study.

“These two parameters are interconnected, but we can estimate them independently by adding extra information obtained by peering through the dust with infrared observations”, continues the expert.

The team combined the second Gaia data release with several infrared surveys using a computer code called StarHorse, developed by co-author Anna Queiroz and other collaborators. The code compares the observations with stellar models to determine the surface temperature of stars, the extinction and an improved estimate of the distance to the stars.

As a result, the astronomers obtained much better determination of the distances to about 150 million stars – in some cases, the improvement is up to 20% or more. This enabled them to trace the distribution of stars across the Milky Way to much greater distances than possible with the original Gaia data alone.

“With the second Gaia data release, we could probe a radius around the Sun of about 6500 light years, but with our new catalogue, we can extend this ‘Gaia sphere’ by three or four times, reaching out to the center of the Milky Way,” explains co-author Cristina Chiappini from Leibniz Institute for Astrophysics Potsdam, Germany, where the project was coordinated.
At the center of our galaxy, the data clearly reveals a large, elongated feature in the three-dimensional distribution of stars: the galactic bar.

“We know the Milky Way has a bar, like other barred spiral galaxies, but so far we only had indirect indications from the motions of stars and gas, or from star counts in infrared surveys. This is the first time that we see the galactic bar in three-dimensional space, based on geometric measurements of stellar distances,” says Friedrich Anders.



Flyby around the StarHorse Gaia DR2 density distribution of Milky Way stars

from Friedrich Anders on Vimeo.

“Ultimately, we are interested in galactic archaeology: we want to reconstruct how the Milky Way formed and evolved, and to do so we have to understand the history of each and every one of its components,” adds Cristina Chiappini.

“It is still unclear how the bar – a large amount of stars and gas rotating rigidly around the centre of the galaxy – formed, but with Gaia and other upcoming surveys in the next years we are certainly on the right path to figure it out”, notes the researcher.

The team is looking forward to the next data release from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE-2), as well as upcoming facilities such as the 4-metre Multi-Object Survey Telescope (4MOST) at the European Southern Observatory in Chile and the WEAVE (WHT Enhanced Area Velocity Explorer) survey at the William Herschel Telescope (WHT) in La Palma (Canary Islands).

The third Gaia data release, currently planned for 2021, will include greatly improved distance determinations for a much larger number of stars, and is expected to enable progress in our understanding of the complex region at the center of the Milky Way.


“With this study, we can enjoy a taster of the improvements in our knowledge of the Milky Way that can be expected from Gaia measurements in the third data release,” explains co-author Anthony Brown of Leiden University (the Netherlands).

“We are revealing features in the Milky Way that we could not see otherwise: this is the power of Gaia, which is enhanced even further in combination with complementary surveys,” concludes Timo Prusti, Gaia project scientist at ESA.



Contacts and sources:
University of Barcelona

Citation: “Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G=18”. F. Anders, A. Khalatyan, C. Chiappini, A. B. Queiroz, B. X. Santiago, C. Jordi, L. Girardi,A. G. A. Brown, G. Matijeviˇc, G. Monari, T. Cantat-Gaudin, M. Weiler, S. Khan, A. Miglio, I. Carrillo, M. Romero-Gómez, I. Minchev2, R. S. de Jong, T. Antoja, P. Ramos, M. Steinmetz, H. Enk. Astronomy & Astrophysics, July 2019.




Space: How Fast Is It Becoming More Vast? The New Measurement



Astronomers have made a new measurement of how fast the universe is expanding, using an entirely different kind of star than previous endeavors. The revised measurement, which comes from NASA's Hubble Space Telescope, falls in the center of a hotly debated question in astrophysics that may lead to a new interpretation of the universe's fundamental properties.

Scientists have known for almost a century that the universe is expanding, meaning the distance between galaxies across the universe is becoming ever more vast every second. But exactly how fast space is stretching, a value known as the Hubble constant, has remained stubbornly elusive.

Now, University of Chicago professor Wendy Freedman and colleagues have a new measurement for the rate of expansion in the modern universe, suggesting the space between galaxies is stretching faster than scientists would expect. Freedman's is one of several recent studies that point to a nagging discrepancy between modern expansion measurements and predictions based on the universe as it was more than 13 billion years ago, as measured by the European Space Agency's Planck satellite.

As more research points to a discrepancy between predictions and observations, scientists are considering whether they may need to come up with a new model for the underlying physics of the universe in order to explain it.

These galaxies are selected from a Hubble Space Telescope program to measure the expansion rate of the universe, called the Hubble constant. The value is calculated by comparing the galaxies' distances to the apparent rate of recession away from Earth (due to the relativistic effects of expanding space). By comparing the apparent brightnesses of the galaxies' red giant stars with nearby red giants, whose distances were measured with other methods, astronomers are able to determine how far away each of the host galaxies are. This is possible because red giants are reliable milepost markers because they all reach the same peak brightness in their late evolution. And, this can be used as a "standard candle" to calculate distance. Hubble's exquisite sharpness and sensitivity allowed for red giants to be found in the stellar halos of the host galaxies. The red giants were searched for in the halos of the galaxies. The center row shows Hubble's full field of view. The bottom row zooms even tighter into the Hubble fields. The red giants are identified by yellow circles.

Credits: NASA, ESA, W. Freedman (University of Chicago), ESO, and the Digitized Sky Survey


"The Hubble constant is the cosmological parameter that sets the absolute scale, size and age of the universe; it is one of the most direct ways we have of quantifying how the universe evolves," said Freedman. "The discrepancy that we saw before has not gone away, but this new evidence suggests that the jury is still out on whether there is an immediate and compelling reason to believe that there is something fundamentally flawed in our current model of the universe.”

In a new paper accepted for publication in The Astrophysical Journal, Freedman and her team announced a new measurement of the Hubble constant using a kind of star known as a red giant. Their new observations, made using Hubble, indicate that the expansion rate for the nearby universe is just under 70 kilometers per second per megaparsec (km/sec/Mpc). One parsec is equivalent to 3.26 light-years distance.

This measurement is slightly smaller than the value of 74 km/sec/Mpc recently reported by the Hubble SH0ES (Supernovae H0 for the Equation of State) team using Cepheid variables, which are stars that pulse at regular intervals that correspond to their peak brightness. This team, led by Adam Riess of the Johns Hopkins University and Space Telescope Science Institute, Baltimore, Maryland, recently reported refining their observations to the highest precision to date for their Cepheid distance measurement technique.

How to Measure Expansion

A central challenge in measuring the universe's expansion rate is that it is very difficult to accurately calculate distances to distant objects.

In 2001, Freedman led a team that used distant stars to make a landmark measurement of the Hubble constant. The Hubble Space Telescope Key Project team measured the value using Cepheid variables as distance markers. Their program concluded that the value of the Hubble constant for our universe was 72 km/sec/Mpc.

But more recently, scientists took a very different approach: building a model based on the rippling structure of light left over from the big bang, which is called the Cosmic Microwave Background. The Planck measurements allow scientists to predict how the early universe would likely have evolved into the expansion rate astronomers can measure today. Scientists calculated a value of 67.4 km/sec/Mpc, in significant disagreement with the rate of 74.0 km/sec/Mpc measured with Cepheid stars.

Astronomers have looked for anything that might be causing the mismatch. "Naturally, questions arise as to whether the discrepancy is coming from some aspect that astronomers don't yet understand about the stars we're measuring, or whether our cosmological model of the universe is still incomplete," Freedman said. "Or maybe both need to be improved upon."

Freedman's team sought to check their results by establishing a new and entirely independent path to the Hubble constant using an entirely different kind of star.

Certain stars end their lives as a very luminous kind of star called a red giant, a stage of evolution that our own Sun will experience billions of years from now. At a certain point, the star undergoes a catastrophic event called a helium flash, in which the temperature rises to about 100 million degrees and the structure of the star is rearranged, which ultimately dramatically decreases its luminosity. Astronomers can measure the apparent brightness of the red giant stars at this stage in different galaxies, and they can use this as a way to tell their distance.

The Hubble constant is calculated by comparing distance values to the apparent recessional velocity of the target galaxies — that is, how fast galaxies seem to be moving away. The team's calculations give a Hubble constant of 69.8 km/sec/Mpc — straddling the values derived by the Planck and Riess teams.

"Our initial thought was that if there's a problem to be resolved between the Cepheids and the Cosmic Microwave Background, then the red giant method can be the tie-breaker," said Freedman.

But the results do not appear to strongly favor one answer over the other say the researchers, although they align more closely with the Planck results.

NASA's upcoming mission, the Wide Field Infrared Survey Telescope (WFIRST), scheduled to launch in the mid-2020s, will enable astronomers to better explore the value of the Hubble constant across cosmic time. WFIRST, with its Hubble-like resolution and 100 times greater view of the sky, will provide a wealth of new Type Ia supernovae, Cepheid variables, and red giant stars to fundamentally improve distance measurements to galaxies near and far.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.


Contacts and sources:
Claire Andreoli
NASA's Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

Louise Lerner
University of Chicago, Chicago, Ill.

Citation: The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch. Authors: Wendy L. Freedman, Barry F. Madore, Dylan Hatt, Taylor J. Hoyt, In-Sung Jang, Rachael L. Beaton, Christopher R. Burns, Myung Gyoon Lee, Andrew J. Monson, Jillian R. Neeley, Mark M. Phillips, Jeffrey A. Rich, Mark Seibert. The Astrophysical Journal (accepted), 2019



Are Cats Getting Fatter?




Are cats getting fatter?

Credit: University of Guelph.


Until now, pet owners and veterinarians didn’t know for sure. Now University of Guelph researchers have become the first to access data on more than 19 million cats to get a picture of typical weight gain and loss over their lifetimes.

The researchers at U of G’s Ontario Veterinary College (OVC) discovered most cats continue to put on weight as they age, and their average weight is on the rise.

The findings, published in the Journal of the American Veterinary Medical Association, reveal that even after cats mature from the kitten phase, their weight still creeps up until they are, on average, eight years old.

This research — the first of its kind to use such a large data pool — provides important baseline information for vets and pet owners about cat weight changes, said Prof. Theresa Bernardo, the IDEXX Chair in Emerging Technologies and Bond-Centered Animal Healthcare.

File:Fat cat.jpg
Credit: brokinhrt2 / Wikimedia Commons
“As humans, we know we need to strive to maintain a healthy weight, but for cats, there has not been a clear definition of what that is. We simply didn’t have the data,” said Bernardo. “Establishing the pattern of cat weights over their lifetimes provides us with important clues about their health.”

Lead author Dr. Adam Campigotto, along with Bernardo and colleague Dr. Zvonimir Poljak, analyzed 54 million weight measurements taken at vets’ offices on 19 million cats as part of his PhD research. The research team broke down the data to stratify any differences over gender, neutering status and breed.

They found male cats tended to reach higher weight peaks than females and spayed or neutered cats tended to be heavier than unaltered cats. Among the four most common purebred breeds (Siamese, Persian, Himalayan and Maine Coon), the mean weight peaked between six and 10 years of age. Among common domestic cats, it peaked at eight years.


Dr. Adam Campigotto

Credit: University of Guelph.

As well, the team noted that the mean weight of neutered, eight-year-old domestic cats increased between 1995 and 2005 but remained steady between 2005 and 2015.

“We do have concerns with obesity in middle age, because we know that can lead to diseases for cats, such as diabetes, heart disease, osteoarthritis and cancer,” said Campigotto.

“Now that we have this data, we can see that cat weights tend to follow a curve. We don’t yet know the ideal weight trajectory, but it’s at least a starting point to begin further studies.”

The team noted that 52 per cent of the cats among the study group had only one body weight measurement on file, which may suggest their owners did not bring the animals back in for regular vet checkups or took them to a different veterinary clinic.

Bernardo said just as humans need to be aware of maintaining a healthy weight as they age, it’s important to monitor weight changes in cats.

“Cats tend to be overlooked because they hide their health problems and they don’t see a vet as often as dogs do. So one of our goals is to understand this so that we can see if there are interventions that can provide more years of healthy life to cats.”

Discussions about body weight throughout a pet’s lifetime could be a useful gateway for veterinarians to engage more cat owners in the health of their pets, she added.

Prof. Theresa Bernardo

Credit: University of Guelph.


“The monitoring of body weight is an important indicator of health in both humans and animals. It’s a data point that is commonly collected at each medical appointment, is simple to monitor at home and is an easy point of entry into data-driven animal wellness.”

For owners concerned about their cat’s health or weight gain, Campigotto advises buying a scale and getting in the habit of weighing their pet.

“If your cat is gaining or losing weight, it may be an indicator of an underlying problem,” he said.

The research team plans to study ways of reducing cat obesity including looking at the use of automated feeders that could dispense the appropriate amount of food for a cat. These feeders could even be equipped with built-in scales.

“We are ultimately changing the emphasis to cat health rather than solely focusing on disease,” said Campigotto. “As we investigate the data and create new knowledge, it will enable veterinarians to offer clients evidence-based wellness plans, allow for earlier identification and treatment of disease and an enhanced quality of life for their animals.”





Contacts and sources:
Lori Bona Hunt, Prof. Theresa Bernardo   Dr. Adam Campigotto
University of Guelph.




Citation: Investigation of relationships between body weight and age among domestic cats stratified by breed and sex.
Adam J. Campigotto, Zvonimir Poljak, Elizabeth A. Stone, Deborah Stacey, Theresa M. Bernardo. Journal of the American Veterinary Medical Association, 2019; 255 (2): 205 DOI: 10.2460/javma.255.2.205



Cannabis Addiction Treatment: First Study of Its Kind

A Sydney-led study published in a JAMA journal provides the first strong evidence that medicinal cannabis could reduce the rate of relapse for users of cannabis - a leading cause of drug treatment episodes in Australia.
File:Cannabis Grow Facility.jpg
cannnabis in warehouse
Credit: My 420 Tours / Wikimedia Commons

An Australian study has demonstrated that cannabis-based medication helps tackle dependency on cannabis, one of the most widely used drugs globally.

A paper about the University of Sydney and NSW Health clinical trial provides the first strong evidence that so-called cannabinoid agonist medication – which targets receptors in the brain – could reduce the rate of relapse.

The paper published today in the American Medical Association’s JAMA Internal Medicine.

Lead author Conjoint Professor Nick Lintzeris – of the University of Sydney’s Faculty of Medicine and Health and Director of Drug & Alcohol Services, South East Sydney Local Health District – said the study should give hope to people with dependency on cannabis, which is a leading cause of drug treatment episodes in Australia.

“We’ve never had the evidence before that medication can be effective in treating cannabis dependency – this is the first big study to show this is a safe and effective approach,” said Professor Lintzeris, from the Sydney Medical School.

“The principles are very similar to nicotine replacement; you are providing patients with a medicine which is safer than the drug they’re already using, and linking this with medical and counselling support to help people address their illicit cannabis use.”

The cannabis concentrate, which comprises equal proportions of cannabidiol (CBD) and the psychoactive tetrahydrocannabinol (THC), is sprayed under the tongue and avoids the health impacts associated with smoking cannabis such as respiratory issues.

Nabiximols has been primarily used to treat pain symptoms associated with multiple sclerosis and is licensed in Australia.

Alternative medical cannabis products exist but these are only available through special access schemes and unlike the trial medication, also require Therapeutic Goods Administration (TGA) approval.

This large 12-week outpatient clinical trial of 128 participants taking nabiximols medication followed an earlier study by the same research team that had previously shown nabiximols reduce withdrawal symptoms in a short-term hospital treatment program.

“The latest study published today is even more important in that it shows that nabiximols can be effective in helping patients achieve longer term changes in their cannabis use,” Prof Lintzeris explains.

Co-author of the paper Professor Iain McGregor, the academic director of the University’s Lambert Initiative for Cannabinoid Therapeutics in the Brain and Mind Centre, noted: “Worldwide we are seeing medicinal cannabis patients transition away from the traditional smoked route of cannabis administration; this new study… complements this trend by showing that an oral spray can be an effective substitute for smoked cannabis in heavy recreational users seeking treatment for their cannabis use.”

Professor Lintzeris said an important element of this National Health and Medical Research Council-supported trial was that only cannabis users were recruited who had previously unsuccessfully tried to curb their use.

“Our study is an important step in addressing the lack of effective treatments – currently, four in five patients relapse to regular use within six months of medical or psychological interventions.”

Trial and medication snapshot
  • During the clinical trial, participants had an average dose of about 18 sprays a day, with each spray of 0.1mL comprising 2.7mg of THC and 2.5mg of CBD
  • Participants treated with nabiximols used significantly less illicit cannabis than patients randomly allocated to placebo medication
  • The medicine was combined with cognitive behavioral therapy (CBT) and other therapeutic support for a holistic approach
  • Health and behavioral benefits of cannabis replacement include that patients are taken out of their usual patterns of use
  • This first large outpatient randomized controlled trial of the cannabis extract medication noted suppression of withdrawal and cravings, with improvements in physical and psychological well-being.

Declaration: The University of Sydney sponsored this study, a National Health and Medical Research Council grant supported research costs, health services were predominantly funded by the participating NSW health services and study medications were provided free by GW Pharmaceuticals.


Contacts and sources:
Vivienne Reiner
University of Sydney



Citation:  Nabiximols for the Treatment of Cannabis Dependence
Nicholas Lintzeris, Anjali Bhardwaj, Llewellyn Mills, Adrian Dunlop, Jan Copeland, Iain McGregor, Raimondo Bruno, Jessica Gugusheff, Nghi Phung, Mark Montebello, Therese Chan, Adrienne Kirby, Michelle Hall, Meryem Jefferies, Jennifer Luksza, Marian Shanahan, Richard Kevin, David Allsop. . JAMA Internal Medicine, 2019; DOI: 10.1001/jamainternmed.2019.1993



New Origin of life insight

Peptides, one of the fundamental building blocks of life, can be formed from the primitive precursors of amino acids under conditions similar to those expected on the primordial Earth, finds a new University College London (UCL) study.

Underwater volcanic vents in Japan. 
Volcanic vents
Source: Flickr, Credit: Pacific Ring of Fire 2004 Expedition, NOAA Office of Ocean Exploration

The findings, published in Nature, could be a missing piece of the puzzle of how life first formed.

“Peptides, which are chains of amino acids, are an absolutely essential element of all life on Earth. They form the fabric of proteins, which serve as catalysts for biological processes, but they themselves require enzymes to control their formation from amino acids,” explained the study’s lead author, Dr Matthew Powner (UCL Chemistry).

“So we’ve had a classic chicken-and-egg problem – how were the first enzymes made?”

He and his team have demonstrated that the precursors to amino acids, called aminonitriles, can be easily and selectively turned into peptides in water, taking advantage of their own built-in reactivity with the help of other molecules that were present in primordial environments.

“Many researchers have sought to understand how peptides first formed to help life develop, but almost all of the research has focused on amino acids, so the reactivity of their precursors was overlooked,” said Dr Powner.

The precursors, aminonitriles, require harsh conditions, typically strongly acidic or alkaline, to form amino acids. And then amino acids must be recharged with energy to make peptides. The researchers found a way to bypass both of these steps, making peptides directly from energy-rich aminonitriles.

They found that aminonitriles have the innate reactivity to achieve peptide bond formation in water with greater ease than amino acids. The team identified a sequence of simple reactions, combining hydrogen sulfide with aminonitriles and another chemical substrate ferricyanide, to yield peptides.

“Controlled synthesis, in response to environmental or internal stimuli, is an essential element of metabolic regulation, so we think that peptide synthesis could have been part of a natural cycle that took place in the very early evolution of life,” said Pierre Canavelli, the first author of the study who completed it while at UCL.

The molecules that served as substrates to help the formation of the amide bonds in the experiments are outgassed during volcanism and are all likely to have been present on the early Earth.

“This is the first time that peptides have been convincingly shown to form without using amino acids in water, using relatively gentle conditions likely to be available on the primitive Earth,” said co-author Dr Saidul Islam (UCL Chemistry).

The findings may also be useful to the field of synthetic chemistry, as amide bond formation is essential for many commercially important synthetic materials, bioactive compounds and pharmaceuticals. The method used in this study is chemically unconventional but follows a pathway to ligate (join together) peptides that mimics biological processes, unlike peptide-building pathways more commonly used in chemistry laboratories that run in the opposite direction and require expensive and wasteful reagents.

The research team is furthering their studies by searching for other pathways to peptides using aminonitriles, and investigating the functional properties of the peptides that their experiments have produced, to better understand how they could have helped kick start life 4 billion years ago.

The research was supported by the Engineering and Physical Sciences Research Council, the Simons Foundation and the Volkswagen Foundation.



Contacts and sources:
Chris Lane
University College London

Citation: Peptide ligation by chemoselective aminonitrile coupling in water.
Pierre Canavelli, Saidul Islam, Matthew W. Powner. Nature, 2019; DOI: 10.1038/s41586-019-1371-4



Joshua Trees Vanishing, Headed to Extinction



They outlived mammoths and saber-toothed tigers. But without dramatic action to reduce climate change, new research shows Joshua trees won’t survive much past this century.  Joshua Tree National Park would retain 0.02 percent of its tree habitat without climate change action

Joshua trees in Joshua Tree National Park
File:Joshuabaum2.jpg
Credit: Lupe / Wikimedia Commons

UC Riverside scientists wanted to verify earlier studies predicting global warming’s deadly effect on the namesake trees that millions flock to see every year in Joshua Tree National Park. They also wanted to learn whether the trees are already in trouble.

Young Joshua trees like this one may be unable to survive under climate change.
Credit: Lynn Sweet / UCR



Using multiple methods, the study arrived at several possible outcomes. In the best-case scenario, major efforts to reduce heat-trapping gasses in the atmosphere would save 19 percent of the tree habitat after the year 2070. In the worst case, with no reduction in carbon emissions, the park would retain a mere 0.02 percent of its Joshua tree habitat.

The team’s findings were published recently in Ecosphere. Project lead Lynn Sweet, a UCR plant ecologist, said she hopes the study inspires people to take protective environmental action. “The fate of these unusual, amazing trees is in all of our hands,” she said. “Their numbers will decline, but how much depends on us.”

To answer their questions about whether climate change is already having an effect, a large group of volunteers helped the team gather data about more than 4,000 trees.

They found that Joshua trees have been migrating to higher elevation parts of the park with cooler weather and more moisture in the ground. In hotter, drier areas, the adult trees aren’t producing as many younger plants, and the ones they do produce aren’t surviving.

Joshua trees as a species have existed since the Pleistocene era, about 2.5 million years ago, and individual trees can live up to 300 years. One of the ways adult trees survive so long is by storing large reserves of water to weather droughts.

Younger trees and seedlings aren’t capable of holding reserves in this way though, and the most recent, 376-week-long drought in California left the ground in some places without enough water to support new young plants. As the climate changes, long periods of drought are likely to occur with more frequency, leading to issues with the trees like those already observed.

An additional finding of this study is that in the cooler, wetter parts of the park the biggest threat other than climate change is fire. Fewer than 10 percent of Joshua trees survive wildfires, which have been exacerbated in recent years by smog from car and industrial exhaust. The smog deposits nitrogen on the ground, which in turn feeds non-native grasses that act as kindling for wildfires.

As a partner on this project, the U.S. Park Service is using this information to mitigate fire risk by removing the invasive plants.

“Fires are just as much a threat to the trees as climate change, and removing grasses is a way park rangers are helping to protect the area today,” Sweet said. “By protecting the trees, they’re protecting a host of other native insects and animals that depend on them as well.”

UCR animal ecologist and paper co-author Cameron Barrows conducted a similar research project in 2012, which also found Joshua tree populations would decline, based on models assuming a temperature rise of three degrees. However, this newer study considered a climate change scenario using twice as many variables, including soil-water estimates, rainfall, soil types, and more. In addition, Barrows said on-the-ground observations were essential to verifying the climate models this newer team had constructed.

UCR researcher and study lead Lynn Sweet (center) and volunteers measure a dead Joshua tree.
Credit: Nicholas Graver/NPS



Quoting the statistician George Box, Barrows said, “All models are wrong, but some are useful.” Barrows went on to say, “Here, the data we collected outdoors showed us where our models gave us the most informative glimpse into the future of the park.”

For this study, the UC Riverside Center for Conservation Biology partnered with Earthwatch Institute to recruit the volunteer scientists. Barrows and Sweet both recommend joining such organizations as a way to help find solutions to the park’s problems.

“I hope members of the public read this and think, ‘Someone like me could volunteer to help scientists get the kind of data that might lend itself to concrete, protective actions,’” Barrows said.



Contacts and sources:
Jules Bernstein
University of California - Riverside

Citation:  Lynn C. Sweet, Tyler Green, James G. C. Heintz, Neil Frakes, Nicolas Graver, Jeff S. Rangitsch, Jane E. Rodgers, Scott Heacox, Cameron W. Barrows. Congruence between future distribution models and empirical data for an iconic species at Joshua Tree National Park. Ecosphere, 2019; 10 (6): e02763 DOI: 10.1002/ecs2.2763

 . Original written by . Note: Content may be edited for style and length.

Journal Reference:


Tuesday, July 16, 2019

New Material To Terraform Mars to Make It Habitable

Silica aerogel could warm the Martian surface similar to the way greenhouse gasses keep Earth warm.

Polar ice caps on Mars are a combination of water ice and frozen CO2. Like its gaseous form, frozen CO2 allows sunlight to penetrate while trapping heat. In the summer, this solid-state greenhouse effect creates pockets of warming under the ice, seen here as black dots in the ice.

Credit: Harvard John A. Paulson School of Engineering and Applied Sciences

People have long dreamed of re-shaping the Martian climate to make it livable for humans. Carl Sagan was the first outside of the realm of science fiction to propose terraforming. In a 1971 paper, Sagan suggested that vaporizing the northern polar ice caps would “yield ~10 s g cm-2 of atmosphere over the planet, higher global temperatures through the greenhouse effect, and a greatly increased likelihood of liquid water.”

Sagan’s work inspired other researchers and futurists to take seriously the idea of terraforming. The key question was: are there enough greenhouse gases and water on Mars to increase its atmospheric pressure to Earth-like levels?

In 2018, a pair of NASA-funded researchers from the University of Colorado, Boulder and Northern Arizona University found that processing all the sources available on Mars would only increase atmospheric pressure to about 7 percent that of Earth – far short of what is needed to make the planet habitable.

Terraforming Mars, it seemed, was an unfulfillable dream.

Now, researchers from the Harvard University, NASA’s Jet Propulsion Lab, and the University of Edinburgh, have a new idea. Rather than trying to change the whole planet, what if you took a more regional approach?

The researchers suggest that regions of the Martian surface could be made habitable with a material — silica aerogel — that mimics Earth’s atmospheric greenhouse effect. Through modeling and experiments, the researchers show that a two to three-centimeter-thick shield of silica aerogel could transmit enough visible light for photosynthesis, block hazardous ultraviolet radiation, and raise temperatures underneath permanently above the melting point of water, all without the need for any internal heat source.

The paper is published in Nature Astronomy.


“This regional approach to making Mars habitable is much more achievable than global atmospheric modification,” said Robin Wordsworth, Assistant Professor of Environmental Science and Engineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Department of Earth and Planetary Science. “Unlike the previous ideas to make Mars habitable, this is something that can be developed and tested systematically with materials and technology we already have.”

“Mars is the most habitable planet in our Solar System besides Earth,” said Laura Kerber, Research Scientist at NASA’s Jet Propulsion Laboratory. “But it remains a hostile world for many kinds of life. A system for creating small islands of habitability would allow us to transform Mars in a controlled and scalable way.”

The researchers were inspired by a phenomenon that already occurs on Mars.

Unlike Earth’s polar ice caps, which are made of frozen water, polar ice caps on Mars are a combination of water ice and frozen CO2. Like its gaseous form, frozen CO2 allows sunlight to penetrate while trapping heat. In the summer, this solid-state greenhouse effect creates pockets of warming under the ice.

“We started thinking about this solid-state greenhouse effect and how it could be invoked for creating habitable environments on Mars in the future,” said Wordsworth. “We started thinking about what kind of materials could minimize thermal conductivity but still transmit as much light as possible.”

The researchers landed on silica aerogel, one of the most insulating materials ever created.

Silica aerogels are 97 percent porous, meaning light moves through the material but the interconnecting nanolayers of silicon dioxide infrared radiation and greatly slow the conduction of heat. These aerogels are used in several engineering applications today, including NASA’s Mars Exploration Rovers.

“Silica aerogel is a promising material because its effect is passive,” said Kerber. “It wouldn’t require large amounts of energy or maintenance of moving parts to keep an area warm over long periods of time.”

Using modeling and experiments that mimicked the Martian surface, the researchers demonstrated that a thin layer of this material increased average temperatures of mid-latitudes on Mars to Earth-like temperatures.

“Spread across a large enough area, you wouldn’t need any other technology or physics, you would just need a layer of this stuff on the surface and underneath you would have permanent liquid water,” said Wordsworth.

This material could be used to build habitation domes or even self-contained biospheres on Mars on Mars.

“There’s a whole host of fascinating engineering questions that emerge from this,” said Wordsworth.

Next, the team aims to test the material in Mars-like climates on Earth, such as the dry valleys of Antarctica or Chile.

Wordsworth points out that any discussion about making Mars habitable for humans and Earth life also raises important philosophical and ethical questions about planetary protection.

“If you’re going to enable life on the Martian surface, are you sure that there’s not life there already? If there is, how do we navigate that,” asked Wordsworth. “The moment we decide to commit to having humans on Mars, these questions are inevitable."



Contacts and sources:
Leah Burrows
Harvard John A. Paulson School of Engineering and Applied Sciences


Citation: Enabling Martian habitability with silica aerogel via the solid-state greenhouse effect.
R. Wordsworth, L. Kerber & C. Cockell. Nature Astronomy, 2019 DOI: 10.1038/s41550-019-0813-0



Why Do Stars Explode? Unique Supernova Provides Clues



When NASA’s Transiting Exoplanet Survey Satellite launched into space in April 2018, it did so with a specific goal: to search the universe for new planets.

But in recently published research, a team of astronomers at The Ohio State University showed that the survey, nicknamed TESS, could also be used to monitor a particular type of supernova, giving scientists more clues about what causes white dwarf stars to explode—and about the elements those explosions leave behind.


Credit: Ohio State University (OSU)

“We have known for years that these stars explode, but we have terrible ideas of why they explode,” said Patrick Vallely, lead author of the study and an Ohio State astronomy graduate student. “The big thing here is that we are able to show that this supernova isn’t consistent with having a white dwarf (take mass) directly from a standard star companion and explode into it—the kind of standard idea that had led to people trying to find hydrogen signatures in the first place. That is, because the TESS light curve doesn’t show any evidence of the explosion slamming into the surface of a companion, and because the hydrogen signatures in the SALT spectra don’t evolve like the other elements, we can rule out that standard model.”



Their research, detailed in the Monthly Notices of the Royal Astronomical Society,represents the first published findings about a supernova observed using TESS, and add new insights to long-held theories about the elements left behind after a white dwarf star explodes into a supernova.

Those elements have long troubled astronomers.

A white dwarf explodes into a specific type of supernova, a 1a, after gathering mass from a nearby companion star and growing too big to remain stable, astronomers believe. But if that is true, then the explosion should, astronomers have theorized, leave behind trace elements of hydrogen, a crucial building block of stars and the entire universe. (White dwarf stars, by their nature, have already burned through their own hydrogen and so would not be a source of hydrogen in a supernova.)

But until this TESS-based observation of a supernova, astronomers had never seen those hydrogen traces in the explosion’s aftermath: This supernova is the first of its type in which astronomers have measured hydrogen. That hydrogen, first reported by a team from the Observatories of the Carnegie Institution for Science, could change the nature of what astronomers know about white dwarf supernovae.

“The most interesting thing about this particular supernova is the hydrogen we saw in its spectra (the elements the explosion leaves behind),” Vallely said. “We’ve been looking for hydrogen and helium in the spectra of this type of supernova for years—those elements help us understand what caused the supernova in the first place.”

Patrick Vallely

Credit: OSU

The hydrogen could mean that the white dwarf consumed a nearby star. In that scenario, the second star would be a normal star in the middle of its lifespan—not a second white dwarf. But when astronomers measured the light curve from this supernova, the curve indicated that the second star was in fact a second white dwarf. So where did the hydrogen come from?

Professor of Astronomy Kris Stanek, Vallely’s adviser at Ohio State and a co-author on this paper, said it is possible that the hydrogen came from a companion star—a standard, regular star—but he thinks it is more likely that the hydrogen came from a third star that happened to be near the exploding white dwarf and was consumed in the supernova by chance.

Kris Stanek

Credit: OSU

“We would think that because we see this hydrogen, it means that the white dwarf consumed a second star and exploded, but based on the light curve we saw from this supernova, that might not be true,” Stanek said.



“Based on the light curve, the most likely thing that happened, we think, is that the hydrogen might be coming from a third star in the system,” Stanek added. “So the prevailing scenario, at least at Ohio State right now, is that the way to make a Type Ia (pronounced 1-A) supernova is by having two white dwarf stars interacting—colliding even. But also having a third star that provides the hydrogen.”

For the Ohio State research, Vallely, Stanek and a team of astronomers from around the world combined data from TESS, a 10-centimeter-diameter telescope, with data from the All-Sky Automated Survey for Supernovae (ASAS-SN for short.) ASAS-SN is led by Ohio State and is made up of small telescopes around the world watching the sky for supernovae in far-away galaxies.

TESS, by comparison, is designed to search the skies for planets in our nearby galaxy—and to provide data much more quickly than previous satellite telescopes. That means that the Ohio State team was able to use data from TESS to see what was happening around the supernova in the first moments after it exploded—an unprecedented opportunity.

The team combined data from TESS and ASAS-SN with data from the South African Large Telescope to evaluate the elements left behind in the supernova’s wake. They found both hydrogen and helium there, two indicators that the exploding star had somehow consumed a nearby companion star.

“What is really cool about these results is, when we combine the data, we can learn new things,” Stanek said. “And this supernova is the first exciting case of that synergy.”

The supernova this team observed was a Type Ia, a type of supernova that can occur when two stars orbit one another—what astronomers call a binary system. In some cases of a Type I supernova, one of those stars is a white dwarf.

A white dwarf has burned off all its nuclear fuel, leaving behind only a very hot core. (White dwarf temperatures exceed 100,000 degrees Kelvin—nearly 200,000 degrees Fahrenheit.) Unless the star grows bigger by stealing bits of energy and matter from a nearby star, the white dwarf spends the next billion years cooling down before turning into a lump of black carbon.

But if the white dwarf and another star are in a binary system, the white dwarf slowly takes mass from the other star until, eventually, the white dwarf explodes into a supernova.

Type I supernovae are important for space science—they help astronomers measure distance in space, and help them calculate how quickly the universe is expanding (a discovery so important that it won the Nobel Prize in Physics in 2011.)

“These are the most famous type of supernova—they led to dark energy being discovered in the 1990s,” Vallely said. “They are responsible for the existence of so many elements in the universe. But we don’t really understand the physics behind them that well. And that’s what I really like about combining TESS and ASAS-SN here, that we can build up this data and use it to figure out a little more about these supernovae.”

Scientists broadly agree that the companion star leads to a white dwarf supernova, but the mechanism of that explosion, and the makeup of the companion star, are less clear.

This finding, Stanek said, provides some evidence that the companion star in this type of supernova is likely another white dwarf.

“We are seeing something new in this data, and it helps our understanding of the Ia supernova phenomenon,” he said. “And we can explain this all in terms of the scenarios we already have—we just need to allow for the third star in this case to be the source of the hydrogen.”

ASAS-SN is supported by Las Cumbres Observatory and funded in part by the Gordon and Betty Moore Foundation, the National Science Foundation, the Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics at Ohio State, the Chinese Academy of Sciences South American Center for Astronomy and the Villum Fonden in Denmark.


Contacts and sources:
Laura Arenschield
Ohio State University


Citation: ASASSN-18tb: a most unusual Type Ia supernova observed by TESS and SALT.
P J Vallely, M Fausnaugh, S W Jha, M A Tucker, Y Eweis, B J Shappee, C S Kochanek, K Z Stanek, Ping Chen, Subo Dong, J L Prieto, T Sukhbold, Todd A Thompson, J Brimacombe, M D Stritzinger, T W-S Holoien, D A H Buckley, M Gromadzki, Subhash Bose.  Monthly Notices of the Royal Astronomical Society, 2019; 487 (2): 2372 DOI: 10.1093/mnras/stz1445