Researchers from Lund University in Sweden, among others, have developed a more effective technique in the search for clues about dark matter in the universe. They can now analyse much larger amounts of the data generated at CERN.
At the CERN research facility, a long series of experiments is underway on protons colliding in the LHC accelerator at almost the speed of light. The amount of data is constantly increasing, as the accelerator's capacity improves. However, it is more difficult to process and store the vast amounts of data that are produced. This is why there is a continuous evaluation of which data the researchers should examine more closely.
"If we are not careful, we could end up discarding data that contains clues to completely new particles of which we are not yet aware, such as particles that form dark matter", explains Caterina Doglioni, a particle physicist at Lund University and a member of the ATLAS experiment at CERN.
She is one of the researchers behind a recent study focusing on how to better utilise CERN's enormous amounts of data. Instead of recording all the information from the experiment and then analysing it at a later date, much of the data analysis is done in a short amount of time so that a much smaller fraction of the event is retained. This technique, that has been employed by other LHC experiments as well, allows researchers to record and store many more events that could contain traces of new particles.
The hope is to find signs of hitherto unknown particles that could be carriers of forces that could create a connection between visible and dark matter, according to Doglioni.
"These new particles, which we call "mediator particles" can disintegrate into extremely short-lived pairs of quarks, i.e. the very building blocks of the protons and neutrons in atoms. When quarks disintegrate, a type of particle shower is formed that we can actually detect with our instruments", says Caterina Doglioni.
The research community has long been searching for answers about the elusive dark matter that makes up a large part of our universe. Only five per cent of the universe is matter that we are currently able to perceive and measure. The remaining 95 per cent is unexplored and referred to as dark matter and dark energy.
Among other things, this assumption is based on the fact that galaxies rotate as though there were significantly more matter than that which we can see. Dark matter is reported to make up 27 per cent of the universe, while 68 per cent is dark energy - considered to be what causes the universe to constantly accelerate in its ongoing expansion. Researchers have declared October 31st "Dark Matter Day", a day with many different events dedicated to dark matter all over the world.
"We know that dark matter exists. Normally it passes through our measurement instruments, but cannot be registered, but in the case of our research we hoped to see the products of particles connected to it. ", says Caterina Doglioni.
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Oct 30, 2018
Alterations to seabed raise fears for future
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| Maps showing areas of the seafloor which have been affected, to varying degrees, by the increasing acidification of the oceans as a result of human activities. |
Normally the deep sea bottom is a chalky white. It's composed, to a large extent, of the mineral calcite (CaCO3) formed from the skeletons and shells of many planktonic organisms and corals. The seafloor plays a crucial role in controlling the degree of ocean acidification. The dissolution of calcite neutralizes the acidity of the CO2, and in the process prevents seawater from becoming too acidic. But these days, at least in certain hotspots such as the Northern Atlantic and the southern Oceans, the ocean's chalky bed is becoming more of a murky brown. As a result of human activities the level of CO2 in the water is so high, and the water is so acidic, that the calcite is simply being dissolved.
The McGill-led research team who published their results this week in a study in PNAS believe that what they are seeing today is only a foretaste of the way that the ocean floor will most likely be affected in future.
Long-lasting repercussions
"Because it takes decades or even centuries for CO2 to drop down to the bottom of the ocean, almost all the CO2 created through human activity is still at the surface. But in the future, it will invade the deep-ocean, spread above the ocean floor and cause even more calcite particles at the seafloor to dissolve," says lead author Olivier Sulpis who is working on his PhD in McGill's Dept. of Earth and Planetary Sciences. "The rate at which CO2 is currently being emitted into the atmosphere is exceptionally high in Earth's history, faster than at any period since at least the extinction of the dinosaurs. And at a much faster rate than the natural mechanisms in the ocean can deal with, so it raises worries about the levels of ocean acidification in future."
In future work, the researchers plan to look at how this deep ocean bed dissolution is likely to evolve over the coming centuries, under various potential future CO2 emission scenarios. They believe that it is critical for scientists and policy makers to develop accurate estimates of how marine ecosystems will be affected, over the long-term, by acidification caused by humans.
How the work was done
Because it is difficult and expensive to obtain measurements in the deep-sea, the researchers created a set of seafloor-like microenvironments in the laboratory, reproducing abyssal bottom currents, seawater temperature and chemistry as well as sediment compositions. These experiments helped them to understand what controls the dissolution of calcite in marine sediments and allowed them to quantify precisely its dissolution rate as a function of various environmental variables. By comparing pre-industrial and modern seafloor dissolution rates, they were able to extract the anthropogenic fraction of the total dissolution rates.
The speed estimates for ocean-bottom currents came from a high-resolution ocean model developed by University of Michigan physical oceanographer Brian Arbic and a former postdoctoral fellow in his laboratory, David Trossman, who is now a research associate at the University of Texas-Austin.
"When David and I developed these simulations, applications to the dissolution of geological material at the bottom of the oceans were far from our minds. It just goes to show you that scientific research can sometimes take unexpected detours and pay unexpected dividends," said Arbic, an associate professor in the University of Michigan Department of Earth and Environmental Sciences.
Trossman adds: "Just as climate change isn't just about polar bears, ocean acidification isn't just about coral reefs. Our study shows that the effects of human activities have become evident all the way down to the seafloor in many regions, and the resulting increased acidification in these regions may impact our ability to understand Earth's climate history."
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Interior northwest Nez Perce used tobacco long before European contact
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| Washington State University researchers David Gang, left, and Shannon Tushingham have found tobacco use among the Nez Perce goes back centuries, with nicotine in pipes 1,200 years old creating "the longest continuous biomolecular record of ancient tobacco smoking from a single region anywhere in the world." |
Shannon Tushingham, a WSU assistant professor and director of its Museum of Anthropology, made the discovery after teaming up with David Gang, a professor in the Institute of Biological Chemistry, to analyze pipes and pipe fragments in the museum's collection.
"Usually in archaeology we just find little pieces of artifacts, things that you might not think much of," she said. "But the information that we can extract from them on a molecular level is phenomenal."
Indeed, writing in the Proceedings of the National Academy of Sciences, the researchers say their dating of various materials reveals "the longest continuous biomolecular record of ancient tobacco smoking from a single region anywhere in the world."
Tushingham first became interested in the subject when, while excavating plank houses in far northern California for her dissertation, she came across two soapstone pipes.
"I just thought, 'Wouldn't it be interesting to know what people were smoking?'" she said. "Then I started looking at the different plants and it wasn't just tobacco. People smoked lots of different plants. I realized it was an open question whether people had smoked tobacco in many places in North America."
Indigenous tobacco is scarce in the cool climate of the northwest. Coyote tobacco, or Nicotiana attenuata, is found mostly on sandy river bars, while the natural range of N. quadrivalvus lies south of southwestern Oregon.
Meanwhile, the more potent dried trade tobacco was easy to transport in bundles, or "twists," and Hudson's Bay Company explorers, fur traders and the Lewis and Clark expedition found an eager audience for it as they came through the region in the 1700 and 1800s.
"This occurred so rapidly and so early in the historic record that a complete understanding of in situ pre-contact smoking practices has been obscured," Tushingham and Gang write in their paper.
In the 1930s, anthropologist Alfred Kroeber oversaw a survey of more than 200 tribes and bands west of the Rocky Mountains. In one of the ensuing monographs, "Salt, Dogs, Tobacco," he reported that the smoking of non-tobacco products was "more universal," with planting confined to a "long irregular area" from the Oregon coast into south-central California. An accompanying map, however, shows three spots in the Columbia River basin where tobacco could have been mixed with kinnikinnick.
Working with Nez Perce tribal leaders, Tushingham and Gang analyzed a dozen pipes and fragments from three sites on the Snake River. Gang said he could use a solvent to get the substance from a pipe and analyze it using mass spectrometry. That left the pipes intact.
The technique extracts molecular amounts of residue on the surface and inside of the pipes, Gang said. "We don't want to destroy them. We don't want to damage them. We had one pipe that was 5,000 years old that we were really worried about that was sandstone."
Results were inconclusive, but the pipe was fine.
The researchers did detect nicotine in pipes from both after and well before Euro-American contact. None appeared to contain arbutin, a compound associated with kinnikinnick.
Because tobacco in the interior northwest needed to be planted, Tushingham said their finding offers a new view of native interactions with the landscape. Indigenous people have often been thought of as "passive consumers of the environment," yet they managed camas and even grew clams on the coast, she said.
"I think it's a very reasonable proposition that people were cultivating tobacco," Tushingham said. "This is just another sign of the sophistication of cultures in this area and how they managed plants and animals."
The researchers hope that their findings will inform native smoking-cessation programs, acknowledging the deep cultural role of tobacco while addressing health problems.
"If we know there's this eons-long use of psychoactive plants, doesn't that tell you something about human physiology, human health?" asked Tushingham. "Isn't that important information to know in terms of what we would do for treating people today, if we know more about the evolutionary history of this powerful plant and its long history of use by people?"
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Synthetic microorganisms allow scientists to study ancient evolutionary mysteries
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| A genetically modified yeast containing an endosymbiotic bacterium. |
By studying one of these engineered organisms-a bacterium whose genome consists of both ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)-the scientists hope to shed light on the early evolution of genetic material, including the theorized transition from a world where most life relied solely on the genetic molecule RNA to one where DNA serves as the primary storehouse of genetic information.
Using a second engineered organism, a genetically modified yeast containing an endosymbiotic bacterium, they hope to better understand the origins of cellular power plants called mitochondria. Mitochondria provide essential energy for the cells of eukaryotes, a broad group of organisms-including humans-that possesses complex, nucleus-containing cells.
The researchers report engineering the microbes in two papers, one published October 29, 2018 in the Proceedings of the National Academy of Sciences (PNAS) and another published August 30, 2018 in Journal of the American Chemical Society (JACS).
"These engineered organisms will allow us to probe two key theories about major milestones in the evolution of living organisms-the transition from the RNA world to the DNA world and the transition from prokaryotes to eukaryotes with mitochondria," says Peter Schultz, PhD, senior author on the papers and president of Scripps Research. "Access to readily manipulated laboratory models enables us to seek answers to questions about early evolution that were previously intractable."
The origins of life on Earth have been a human fascination for millennia. Scientists have traced the arc of life back several billion years and concluded that the simplest forms of life emerged from Earth's primordial chemical soup and subsequently evolved over the eons into organisms of greater and greater complexity. A monumental leap came with the emergence of DNA, a molecule that stores all of the information required to replicate life and directs cellular machinery to do its bidding primarily by generating RNA, which in turn directs the synthesis of proteins, the molecular workhorses in cells.
In the 1960s, Carl Woese and Leslie Orgel, along with DNA pioneer Francis Crick, proposed that before DNA, organisms relied on RNA to carry genetic information, a molecule similar to but far less stable than DNA, that can also catalyze chemical reactions like proteins. "In science class, students learn that DNA leads to RNA which in turn leads to proteins-that's a central dogma of biology-but the RNA world hypothesis turns that on its head," says Angad Mehta, PhD, first author of the new papers and a postdoctoral research associate at Scripps Research. "For the RNA world hypothesis to be true, you have to somehow get from RNA to a DNA genome, yet how that might have happened is still a very big question among scientists."
One possibility is that the transition proceeded through a kind of microbial missing link, a replicating organism that stored genetic information as RNA. For the JACS study, the Scripps Research-led team created Escherichia coli bacteria that partially build their DNA with ribonucleotides, the molecular building blocks typically used to build RNA. These engineered genomes contained up to 50 percent RNA, thus simultaneously representing a new type of synthetic organism and possibly a throwback to billions of years ago.
Mehta cautions that their work so far has focused on characterizing this chimeric RNA-DNA genome and its effect on bacterial growth and replication but hasn't explicitly explored questions about the transition from the RNA world to the DNA world. But, he says, the fact that E. coli with half its genome comprised of RNA can survive and replicate is remarkable and seems to support the possibility of the existence of evolutionarily transitional organisms possessing hybrid RNA-DNA genomes. The Scripps Research team is now studying how the mixed genomes of their engineered E. coli function and plans to use the bacteria to explore a number of evolutionary questions.
For instance, one question is whether the presence of RNA leads to rapid genetic drift-large changes in gene sequence in a population over time. Scientists theorize that massive genetic drift occurred quickly during early evolution, and the presence in the genome of RNA could help explain how genetic change occurred so quickly.
In the paper published in PNAS, the researchers report engineering another laboratory model for an evolutionary milestone thought to have occurred more than 1.5 billion years ago. They created a yeast dependent for energy on bacteria living inside it as a beneficial parasite or "endosymbiont." This composite organism will allow them to investigate the ancient origins of mitochondria-tiny, bacteria-like organelles that produce chemical energy within the cells of all higher organisms.
Mitochondria are widely thought to have evolved from ordinary bacteria that were captured by larger, single-celled organisms. They carry out several key functions in cells. Most importantly, they serve as oxygen reactors, using O2 to make cells' basic unit of chemical energy, the molecule ATP. As crucial as mitochondria are to cells, their origins remain somewhat mysterious, although there are clear hints of descent from a more independent organism, widely assumed to have been a bacterium.
Mitochondria have a double-membrane structure like that of some bacteria, and-again, like bacteria-contain their own DNA. Analyses of the mitochondrial genome suggest that it shares an ancient ancestor with modern Rickettsia bacteria, which can live within the cells of their hosts and cause disease. Stronger support for the bacterial origin of mitochondria theory would come from experiments showing that independent bacteria could indeed be transformed, in an evolution-like progression, into mitochondria-like symbionts. To that end, the Scripps Research scientists engineered E. coli bacteria that could live in, depend upon, and provide key assistance to, cells of Saccharomyces cerevisiae, also known as baker's yeast.
The researchers started by modifying E. coli to lack the gene encoding thiamin, making the bacteria dependent on the yeast cells for this essential vitamin. At the same time, they added to the bacteria a gene for ADP/ATP translocase, a transporter protein, so that ATP produced within the bacterial cells would be supplied to their yeast-cell hosts-mimicking the central function of real mitochondria. The team also modified the yeast so that their own mitochondria were deficient at supplying ATP. Thus the yeast would be dependent on the bacteria for normal, mitochondria-based ATP production.
The team found that some of the engineered bacteria, after being modified with surface proteins to protect them from being destroyed in the yeast, lived and proliferated in harmony with their hosts for more than 40 generations and appeared to be viable indefinitely. "The modified bacteria seem to accumulate new mutations within the yeast to better adapt to their new surroundings," says Schultz.
With this system established, the team will try to evolve the E. coli to become mitochondria-like organelles. For the new E. coli endosymbiont, adapting to life inside yeast could allow it an opportunity to radically slim its genome. A typical E. coli bacterium, for example, has several thousand genes, whereas mitochondria have evolved a stripped-down set of just 37.
The Scripps Research team rounded out the study with further gene-subtraction experiments, and the results were promising: they found they could eliminate not just the E. coli thiamin gene but also the genes underlying the production of the metabolic molecule NAD and the amino acid serine, and still get a viable symbiosis.
"We are now well on our way to showing that we can delete the genes for making all 20 amino acids, which comprise a significant part of the E. coli genome," says Schultz. "Once we've achieved that, we'll move on to deleting genes for the syntheses of cofactors and nucleotides, and within a few years we hope to be able to get a truly minimal endosymbiotic genome."
Read more at Science Daily
Oct 29, 2018
Astronomers witness slow death of nearby galaxy
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| This is CSIRO's powerful Australian SKA Pathfinder (ASKAP) radio telescope. |
The new peer-reviewed study of the Small Magellanic Cloud (SMC), which is a tiny fraction of the size and mass of the Milky Way galaxy, uses images taken with CSIRO's powerful Australian SKA Pathfinder (ASKAP) radio telescope.
Lead researcher Professor Naomi McClure-Griffiths from ANU said the features of the radio images were more than three times finer than previous SMC images, which allowed the team to probe the interactions between the small galaxy and its environment with more accuracy.
"We were able to observe a powerful outflow of hydrogen gas from the Small Magellanic Cloud," said Professor McClure-Griffiths from the Research School of Astronomy and Astrophysics at ANU.
"The implication is the galaxy may eventually stop being able to form new stars if it loses all of its gas. Galaxies that stop forming stars gradually fade away into oblivion. It's sort of a slow death for a galaxy if it loses all of its gas."
Professor McClure-Griffiths said the discovery, which is part of a project that investigates the evolution of galaxies, provided the first clear observational measurement of the amount of mass lost from a dwarf galaxy.
"The result is also important because it provides a possible source of gas for the enormous Magellanic Stream that encircles the Milky Way," she said.
"Ultimately, the Small Magellanic Cloud is likely to eventually be gobbled up by our Milky Way."
CSIRO co-researcher Dr David McConnell said ASKAP was unrivalled in the world for this kind of research due to its unique radio receivers that give it a panoramic view of the sky.
"The telescope covered the entire SMC galaxy in a single shot and photographed its hydrogen gas with unprecedented detail," he said.
Hydrogen is the most abundant element in the Universe, and is the main ingredient of stars.
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Improving climate models to account for plant behavior yields 'goodish' news
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| Photosynthesis-inactive period nutrient uptake is a large proportion of annual uptake globally. This map shows the fraction of annual plant nitrogen uptake that occurs during photosynthesis-inactive periods. |
In a study published today in Nature Climate Change, lead author William Riley demonstrates how to improve climate models to more accurately represent land biogeochemical dynamics. Using a new global land model they developed and integrated in DOE's Energy Exascale Earth System Model (E3SM), Riley and his team found that plants can uptake more carbon dioxide and soils lose less nitrous oxide than previously thought. Their global simulations imply weaker terrestrial ecosystem feedbacks with the atmosphere than current models predict.
"This is goodish news, with respect to what is currently in the climate models," said Riley, a scientist in Berkeley Lab's Earth & Environmental Sciences Area. "But it's not good news in general -- it's not going to solve the problem. No matter what, plants will not keep up with anthropogenic carbon dioxide emissions; it's just that they might do better than current models suggest."
Humans have emitted a record-setting 34 gigatons of CO2 per year, averaged over the past decade. Roughly half of that remains in the atmosphere, while the rest is absorbed by oceans and land (through photosynthesis); the latter amount, called the terrestrial carbon sink, varies year to year depending on factors such as fires, drought, land use, and weather.
Scientists are trying to understand how increasing global carbon dioxide emissions will affect the terrestrial carbon sink, which is estimated to currently be between 0 and 11 gigatons of CO2 per year, including land-use change, with large inter-annual variability. A further complication involves terrestrial nitrous oxide, which is a powerful greenhouse gas naturally released from land and by agricultural and industrial activities. In other words, to what extent will plants be able to ameliorate increases in anthropogenic carbon dioxide emissions?
The new Berkeley Lab study found that by not properly accounting for what plants do at night and during the non-growing season, climate models may be underestimating the terrestrial carbon sink and overestimating nitrous oxide release, the latter by 2.4 gigatons of CO2-equivalent per year. "This number is substantial compared to the current terrestrial carbon sink," Riley said, anywhere from roughly one-quarter to more than 100 percent, depending on the year.
Plant-microbe competition for nutrients
Plants' ability to take in carbon dioxide is limited by the availability of soil nutrients, especially nitrogen and phosphorus. The more abundant nutrients are, the more plants can take advantage of increasing atmospheric carbon dioxide. Microbes in the soil are a factor too because they compete with plants for nutrients.
Microbes, in fact, play an important role in the carbon cycle, and interactions between plants, soil, and microbes are complex, presenting a challenge to climate scientists. Most climate models assume that plants compete for nutrients in the soil only when they're demanding it for photosynthesis, and not, for example, at night or in non-growing seasons.
"What most climate models have ignored is this pretty robust observational literature showing plants acquire nitrogen from soil even when they're not photosynthesizing," Riley said.
Berkeley Lab has been focused on the topic of plant-soil-microbe interactions through its Microbes to Biomes initiative, and it will be a core theme of the Biological and Environmental Program Integration Center, or BioEPIC, a proposed facility that would house one-of-a-kind experimental capabilities to advance DOE's mission objectives in energy and environmental science. One aim is to represent and study these processes at scale and in a controlled way.
"This study demonstrates progress in more mechanistically representing the terrestrial processes that are important for climate and will be important for BioEPIC," Riley said.
Lower nitrous oxide emissions
In this study, Berkeley Lab researcher Qing Zhu, a co-author of the paper, conducted a meta-analysis of 120 experiments of short-term nitrogen uptake by plants to test their new global land model, named ELMv1. "We also compared observations of nutrient uptake at nighttime versus daytime and across non-growing seasons," Riley said. "We're pretty confident that the basic mechanisms in the model are correct and this meta-analysis and individual site observations back that up."
They found that a significant portion of nutrient uptake takes place in the absence of photosynthesis as plants and microbes compete for nutrients. "The amounts vary a lot by latitude, but in the higher latitudes, such as the Arctic, roughly 20 percent of plants' annual nitrogen uptake occurs outside the growing season. That goes up to 55 percent for nighttime uptake in the tropics," he said. "That's a huge deal for plants and will facilitate atmospheric carbon uptake, and it's currently completely ignored in most climate models."
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Rare blue asteroid reveals itself during fly-by
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| An artist's illustration of what Phaeton might look like up close. |
Kareta presented the results during a press conference on Oct. 23 at the 50th annual meeting of the American Astronomical Society's Division for Planetary Science in Knoxville, Tennessee.
Using telescopes in Hawaii and Arizona, the team studied sunlight reflected off Phaethon, which is known to be blue in color. Blue asteroids, which reflect more light in the blue part of the spectrum, make up only a fraction of all known asteroids. A majority of asteroids are dull grey to red, depending on the type of material on their surface.
Phaethon sets itself apart for two reasons: it appears to be one of the "bluest" of similarly colored asteroids or comets in the solar system; and its orbit takes it so close to the sun that its surface heats up to about 800 degrees Celsius (1,500 degrees Fahrenheit), hot enough to melt aluminum.
Astronomers have been intrigued by Phaethon for other reasons, too. It has the qualities of both an asteroid and a comet based on its appearance and behavior.
Phaethon always appears as a dot in the sky, like thousands of other asteroids, and not as a fuzzy blob with a tail, like a comet. But Phaethon is the source of the annual Geminid meteor shower, easily seen in early-to-mid December.
Meteor showers occur when Earth passes through the trail of dust left behind on a comet's orbit. When they occur and where they appear to originate from depends on how the comet's orbit is oriented with respect to the Earth. Phaethon is thought to be the "parent body" of the Geminid meteor shower because its orbit is very similar to the orbit of the Geminid meteors.
Until Phaeton was discovered in 1983, scientists linked all known meteor showers to active comets and not asteroids.
"At the time, the assumption was that Phaethon probably was a dead, burnt-out comet," Kareta said, "but comets are typically red in color, and not blue. So, even though Phaeton's highly eccentric orbit should scream 'dead comet,' it's hard to say whether Phaethon is more like an asteroid or more like a dead comet."
Phaethon also releases a tiny dust tail when it gets closest to the sun in a process that is thought to be similar to a dry riverbed cracking in the afternoon heat. This kind of activity has only been seen on two objects in the entire solar system -- Phaeton and one other, similar object that appears to blur the line traditionally thought to set comets and asteroids apart.
The team obtained several new insights about Phaethon after analyzing data obtained from NASA's Infrared Telescope Facility on Mauna Kea in Hawaii and the Tillinghast telescope, operated by the Smithsonian Astrophysical Observatory on Mount Hopkins in Arizona. They think Phaethon might be related or have broken off from (2) Pallas, a large blue asteroid farther out in the solar system.
"Interestingly, we found Phaethon to be even darker than had been previously observed, about half as reflective as Pallas," Kareta said. "This makes it more difficult to say how Phaethon and Pallas are related."
The team also observed that Phaethon's blue color is the same on all parts of its surface, which indicates it has been cooked evenly by the Sun in the recent past.
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Obese mice lose a third of their fat using a natural protein
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| Lab mouse. |
The study, published in Scientific Reports, suggests that the protein FGFBP3 (BP3 for short) might offer novel therapy to reverse disorders associated with metabolic syndrome, such as type 2 diabetes and fatty liver disease.
Because BP3 is a natural protein and not an artificial drug, clinical trials of recombinant human BP3 could begin after a final round of preclinical studies, investigators say.
"We found that eight BP3 treatments over 18 days was enough to reduce the fat in obese mice by over a third," says the study's senior investigator, Anton Wellstein, MD, PhD, a professor of oncology and pharmacology at Georgetown Lombardi Comprehensive Cancer Center.
The treatments also reduced a number of obesity-related disorders in the mice, such as hyperglycemia -- excess blood sugar that is often linked to diabetes -- and eliminated the fat in their once fatty livers. Clinical as well as microscopic examination of the mice showed no side effects, researchers say.
Obesity, which affects more than 650 million people worldwide, is the major driver for metabolic syndromes, which includes disorders such as insulin resistance, glucose intolerance, hypertension and elevated lipids in the blood.
BP3 belongs to the family of fibroblast growth factor (FGF) binding proteins (BP). FGFs are found in organisms ranging from worms to humans and are involved in a wide range of biological processes, such as regulating cell growth, wound healing and response to injury. Some FGFs act like hormones.
BP1, 2, and 3 are "chaperone" proteins that latch on to FGF proteins and enhance their activities in the body. Wellstein has long researched the BP1 gene because its production is elevated in a range of cancers, suggesting that growth of some cancers is linked to the excess delivery of FGFs. Only recently has Wellstein turned his attention, and that of his lab and colleagues, to BP3 to understand its role.
The researchers found that this chaperone binds to three FGF proteins (19, 21, and 23) that are involved in the control of metabolism. FGF19 and FGF 21 signaling regulates the storage and use of carbohydrates (sugars) and lipids (fats). FGF23 controls phosphate metabolism.
"We found that BP3 exerts a striking contribution to metabolic control," Wellstein says. "When you have more BP3 chaperone available, FGF19 and FGF21 effect is increased through the increase of their signaling. That makes BP3 a strong driver of carbohydrate and lipid metabolism. It's like having a lot more taxis available in New York City to pick up all the people who need a ride."
"With metabolism revved up, sugar in the blood, and fat processed in the liver are used for energy and is not stored," Wellstein says. "And warehouses of fat are tapped as well. For example, the job of FGF21 is to control break down of fat, whether it is stored or just eaten."
Read more at Science Daily
Oct 28, 2018
A single genetic switch changes butterfly wing color
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| Heliconius cydno butterflies have either white or yellow markings on their wings, which is controlled by a single gene. |
To conduct the study, which was published Oct. 25 in Current Biology, the researchers developed a genetic map using white and yellow H. cydno butterflies. They then studied genome sequences to identify a single gene called aristaless1 (al1) that acted as a switch for yellow and white coloration.
Most Heliconius species closely related to H. cydno have yellow spots on their wings; H. cydno has subspecies that are either yellow or white. The researchers saw that the butterflies with white spots have elevated expression of al1 (i.e. it's switched "on"), meaning that it may play a role in repressing yellow pigmentation from being produced. Using CRISPR/Cas9 gene editing tools, the scientists confirmed this function of al1. When they knocked it out (or switched it off) in embryos of butterflies that should be white, those butterflies developed yellow spots instead.
"For decades people have been cross-breeding these butterflies and they knew that this white vs. yellow switch was in one spot in the genome. They just weren't able to trace it to the actions of a single gene," said Marcus Kronforst, PhD, associate professor of ecology and evolution and senior author of the study.
"Now with CRISPR we can knock the gene out and see what happens. It turns out the evolutionary innovation here is not one species gaining a pigment, but instead turning on a gene to repress an ancestrally present pigment," he said.
Kronforst and his team also traced the evolutionary history this color patterning by comparing genetic differences in the H. cydno version of al1 to those of other, closely-related Heliconius species. The white version of the gene appears to be a relatively new development. While H. cydno was the first species to develop white forms, there are signs of cross-breeding that introduced the white color into other species at a later time.
There is also evidence that the same gene may be linked to mating preferences for color. White H. cydno males prefer females with white spots; yellow males likewise prefer yellow females. Scientists have long known that genes for both color patterning and mate preference in H. cydno are located in the same area of the genome.
"Now that we know the molecular basis of the color, we can start asking how preference is linked to it," Kronforst said. "Are they two genes near one another or is it somehow the same gene doing both jobs?"
While Kronforst and his team don't yet know if mate preference is controlled by al1 or another gene nearby, the close proximity could account for the diversity of Heliconius species.
"Whether it was natural selection driving it or it was just chance that these two things are linked, that might be part of the reason why we have such a diverse group of butterflies," he said. "When the color and preference for the color are linked together, it causes these things to evolve together very rapidly."
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The ghost of Cassiopeia
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| IC 63 -- nicknamed the Ghost Nebula -- is about 550 light-years from Earth. The nebula is classified as both a reflection nebula -- as it is reflecting the light of a nearby star -- and as an emission nebula -- as it releases hydrogen-alpha radiation. Both effects are caused by the gigantic star Gamma Cassiopeiae. The radiation of this star is also slowly causing the nebula to dissipate. |
The constellation of Cassiopeia (constellation)], named after a vain queen in Greek mythology, forms the easily recognisable "W" shape in the night sky. The central point of the W is marked by a dramatic star named Gamma Cassiopeiae.
The remarkable Gamma Cassiopeiae is a blue-white subgiant that is surrounded by a gaseous disc. This star is 19 times more massive and 65,000 times brighter than our Sun. It also rotates at the incredible speed of 1.6 million kilometres per hour -- more than 200 times faster than our parent star. This frenzied rotation gives it a squashed appearance. The fast rotation causes eruptions of mass from the star into a surrounding disk. This mass loss is related to the observed brightness variations.
The radiation of Gamma Cassiopeiae is so powerful that it even affects IC 63, sometimes nicknamed the Ghost Nebula, that lies several light years away from the star. IC 63 is visible in this image taken by the NASA/ESA Hubble Space Telescope.
The colours in the eerie nebula showcase how the nebula is affected by the powerful radiation from the distant star. The hydrogen within IC 63 is being bombarded with ultraviolet radiation from Gamma Cassiopeiae, causing its electrons to gain energy which they later release as hydrogen-alpha radiation -- visible in red in this image.
This hydrogen-alpha radiation makes IC 63 an emission nebula, but we also see blue light in this image. This is light from Gamma Cassiopeiae that has been reflected by dust particles in the nebula, meaning that IC 63 is also a reflection nebula.
This colourful and ghostly nebula is slowly dissipating under the influence of ultraviolet radiation from Gamma Cassiopeiae. However, IC 63 is not the only object under the influence of the mighty star. It is part of a much larger nebulous region surrounding Gamma Cassiopeiae that measures approximately two degrees on the sky -- roughly four times as wide as the full Moon.
This region is best seen from the Northern Hemisphere during autumn and winter. Though it is high in the sky and visible all year round from Europe, it is very dim, so observing it requires a fairly large telescope and dark skies.
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