. Scientific Frontline

Thursday, September 1, 2022

These mice grow bigger on the rainier sides of mountains. It might be a new rule of nature

Shaggy soft-haired mouse Abrothrix hirta (Order Rodentia, Family Cricetidae)
Resized Image using AI by SFLORG
Credit: Pablo Teta

Scientists studying mice from the Andes Mountains in Patagonia noticed something they couldn’t explain: the mice from the western side of the mountains were bigger than the ones from the east, but DNA said that they were all from the same species. The researchers examined the skulls of 450 mice from the southern tip of South America, and found that existing biological laws didn’t explain the size differences. Instead, in a new paper in the Journal of Biogeography, the scientists put forth a new hypothesis: the mice on the western slopes were bigger because that side of the mountain range gets more rain, which means there’s more plentiful food for the mice to eat.

“There are a bunch of ecogeographic rules that scientists use to explain trends that we see again and again in nature,” says Noé de la Sancha, a research associate at Chicago’s Field Museum, an assistant professor of Environmental Science and Studies at DePaul University, and the paper’s corresponding author. “With this paper, I think we might have found a new one: the rain shadow effect can cause changes of size and shape in mammals.”

The mice that de la Sancha and his colleagues examined in this study are shaggy soft-haired mice, Abrothrix hirta. “They’re very cute little buggers, they have soft white bellies,” says de la Sancha. “They live in the mountains, which makes them unique, but they’re also found in lower elevations. Overall, they’re not very well-studied.”

New methodology predicts coronavirus and other infectious disease threats to wildlife

The rate that emerging wildlife diseases infect humans has steadily increased over the last three decades. Viruses, such as the global coronavirus pandemic and recent monkeypox outbreak, have heightened the urgent need for disease ecology tools to forecast when and where disease outbreaks are likely. A University of South Florida assistant professor helped develop a methodology that will do just that – predict disease transmission from wildlife to humans, from one wildlife species to another and determine who is at risk of infection.

The methodology is a machine-learning approach that identifies the influence of variables, such as location and climate, on known pathogens. Using only small amounts of information, the system is able to identify community hot spots at risk of infection on both global and local scales.

“Our main goal is to develop this tool for preventive measures,” said co-principal investigator Diego Santiago-Alarcon, assistant professor of integrative biology. “It’s difficult to have an all-purpose methodology that can be used to predict infections across all the diverse parasite systems, but with this research, we contribute to achieving that goal.”

With help from researchers at the Universiad Veracruzana and Instituto de Ecologia, located in Mexico, Santiago-Alarcon examined three host-pathogen systems – avian malaria, birds with West Nile virus and bats with coronavirus – to test the reliability and accuracy of the models generated by the methodology.

Recycling Greenhouse Gases

Florian Schrenk (left) and Christoph Rameshan
Source/Credit: Technische Universität Wien

CO2 and methane can be turned into valuable products. But until now the catalysts required for such reactions quickly lose their effectiveness. TU Wien has now developed more stable alternatives.

Wherever the production of harmful greenhouse gases cannot be prevented, they should be converted into something useful: this approach is called "carbon capture and utilization". Special catalysts are needed for this. Until now, however, the problem has been that a layer of carbon quickly forms on these catalysts - this is called "coking" - and the catalyst loses its effect. At TU Wien, a new approach was taken: tiny metallic nanoparticles were produced on perovskite crystals through special pre-treatment. The interaction between the crystal surface and the nanoparticles then ensures that the desired chemical reaction takes place without the dreaded coking effect.

Dry reforming: Greenhouse gases become synthesis gas

Carbon dioxide (CO2) and methane are the two human-made greenhouse gases that contribute most to climate change. Both gases often occur in combination, for example in biogas plants. "So-called methane dry reforming is a method that can be used to convert both gases into useful synthesis gas at the same time," says Prof. Christoph Rameshan from the Institute of Materials Chemistry at TU Wien. "Methane and carbon dioxide are turned into hydrogen and carbon monoxide - and it is then relatively easy to produce other hydrocarbons from them, right up to biofuels."

Eight new species of tiny geckos tumbling out of Madagascar’s rainforests

 Seven of the new species of dwarf geckos described from Madagascar.
Credit: P.-S. Gehring, H.-P. Berghof, M. Vences & M.D.

An international team has discovered and named eight new day gecko species from Madagascar, and each of them is no longer than your pointer finger.

Researchers working in the rainforests of Madagascar have been studying the tiny brown Lygodactylus geckos in the subgenus Domerguella for decades. All this time they have been trying to understand their distribution and evolution, thinking that there were just five species. Now, based on analysis of their DNA and careful examination of their scales and proportions, an international team has discovered that there may be as many as seventeen! They have named eight new species in the journal Zootaxa.

In some places, the team found there were three or four different species found in the same place. ‘This was a remarkable discovery’ says Professor Miguel Vences of the Technische Universität Braunschweig, Germany, first author on the study, ‘On Montagne d’Ambre in the north of Madagascar we thought we were collecting just one species, but now we find there are four. Four different, closely related species that are almost indistinguishable to us, occurring together in the same place, apparently without interbreeding—this is exceptional, even for Madagascar.’

Indeed, Madagascar has remarkably high levels of reptile diversity and endemism, and over 150 new species have been discovered and named in the last thirty years. ‘These results highlight how important it is that we continue to collect samples across Madagascar, even of species we think we understand,’ says Dr Frank Glaw, Curator of Herpetology at the Zoologische Staatssammlung München in Munich, Germany, ‘There is still very much more to discover.’

Webb takes its first exoplanet image

This image shows the exoplanet HIP 65426 b in different bands of infrared light, as seen from the James Webb Space Telescope: purple shows the NIRCam instrument’s view at 3.00 micrometers, blue shows the NIRCam instrument’s view at 4.44 micrometers, yellow shows the MIRI instrument’s view at 11.4 micrometers, and red shows the MIRI instrument’s view at 15.5 micrometers.
Credit: NASA/ESA/CSA, A Carter (UCSC), the ERS 1386 team and A. Pagan (STScI)

For the first time, astronomers have used the NASA/ESA/CSA James Webb Space Telescope to take a direct image of an exoplanet. The exoplanet is a gas giant, meaning it has no rocky surface and could not be habitable. The image, as seen through four different light filters, shows how Webb’s powerful infrared gaze can easily capture worlds beyond our Solar System, pointing the way to future observations that will reveal more information than ever before about exoplanets.

The exoplanet in Webb’s image, called HIP 65426 b, is about six to eight times the mass of Jupiter. It is young as planets go – about 15 to 20 million years old, compared to our 4.5-billion-year-old Earth.

Astronomers discovered the planet in 2017 using the SPHERE instrument on the European Southern Observatory’s Very Large Telescope in Chile and took images of it using short infrared wavelengths of light. The Webb image, taken in mid-infrared light, reveals new details that ground-based telescopes would not be able to detect because of the intrinsic infrared glow of Earth’s atmosphere.

Scientists discover surprise anticancer properties of common lab molecule

Nobel laureate Dr. Aziz Sancar at an event in 2016.
Photo credit: Jon Gardiner/UNC-Chapel Hill

Scientists at the UNC School of Medicine have made the surprising discovery that a molecule called EdU, which is commonly used in laboratory experiments to label DNA, is in fact recognized by human cells as DNA damage, triggering a runaway process of DNA repair that is eventually fatal to affected cells, including cancer cells.

The discovery, published in the Proceedings of the National Academy of Sciences, points to the possibility of using EdU as the basis for a cancer treatment, given its toxicity and its selectivity for cells that divide fast.

“The unexpected properties of EdU suggest it would be worthwhile to conduct further studies of its potential, particularly against brain cancers,” said study senior author Dr. Aziz Sancar, the Sarah Graham Kenan Professor of Biochemistry and Biophysics at the UNC School of Medicine and member of the UNC Lineberger Comprehensive Cancer Center. “We want to stress that this is a basic but important scientific discovery. The scientific community has much work ahead to figure out if EdU could actually become a weapon against cancer.”

EdU (5-ethynyl-2′-deoxyuridine) is essentially a popular scientific tool first synthesized in 2008 as an analog, or chemical mimic, of the DNA building block thymidine – which represents the letter “T” in the DNA code of adenine (A), cytosine (C), guanine (G) and thymine (T). Scientists add EdU to cells in lab experiments to replace the thymidine in DNA. Unlike other thymidine analogs, it has a convenient chemical “handle” to which fluorescent probe molecules will bond tightly. It thus can be used relatively easily and efficiently to label and track DNA, for example in studies of the DNA replication process during cell division.

Soaking up the sun with artificial intelligence

Machine learning methods are being developed at Argonne to advance solar energy research with perovskites.
Credit: Maria Chan/ Argonne National Laboratory

The sun continuously transmits trillions of watts of energy to the Earth. It will be doing so for billions more years. Yet, we have only just begun tapping into that abundant, renewable source of energy at affordable cost.

Solar absorbers are a material used to convert this energy into heat or electricity. Maria Chan, a scientist in the U.S. Department of Energy’s (DOE) Argonne National Laboratory, has developed a machine learning method for screening many thousands of compounds as solar absorbers. Her co-author on this project was Arun Mannodi-Kanakkithodi, a former Argonne postdoc who is now an assistant professor at Purdue University.

“We are truly in a new era of applying AI and high-performance computing to materials discovery.” — Maria Chan, scientist, Center for Nanoscale Materials

“According to a recent DOE study, by 2035, solar energy could power 40% of the nation’s electricity,” said Chan. ​“And it could help with decarbonizing the grid and provide many new jobs.”

Corals pass mutations acquired during their lifetimes to offspring

The Elkhorn coral, Acropora palmata, grows into large stands via polyp budding and fragmentation so that many colonies belong to the same clone or genet. During growth, mutations can accumulate in its cells and new research shows that the Ekhorn coral is able to pass these mutations onto to their sexual offspring. This is unlike most animals that prevent such a transfer from the body to reproductive cells.
 Credit: Ilian Baums / Penn State. Creative Commons

In a discovery that challenges over a century of evolutionary conventional wisdom, corals have been shown to pass somatic mutations — changes to the DNA sequence that occur in non-reproductive cells — to their offspring. The finding, by an international team of scientists led by Penn State biologists, demonstrates a potential new route for the generation of genetic diversity, which is the raw material for evolutionary adaptation, and could be vital for allowing endangered corals to adapt to rapidly changing environmental conditions.

“For a trait, such as growth rate, to evolve, the genetic basis of that trait must be passed from generation to generation,” said Iliana Baums, professor of biology at Penn State and leader of the research team. “For most animals, a new genetic mutation can only contribute to evolutionary change if it occurs in a germline or reproductive cell, for example in an egg or sperm cell. Mutations that occur in the rest of the body, in the somatic cells, were thought to be evolutionarily irrelevant because they do not get passed on to offspring. However, corals appear to have a way around this barrier that seems to allow them to break this evolutionary rule.”

Since the time of Darwin, our understanding of evolution has become ever more detailed. We now know that an organism’s traits are heavily determined by the sequence of their DNA. Individuals in a population vary in their DNA sequence, and this genetic variation can lead to the variation in traits, such as body size, that could give an individual a reproductive advantage. Only rarely does a new genetic mutation occur that gives an individual such a reproductive advantage and evolution can only proceed further if — and this is the key — the individual can pass the change to its offspring.

Cannabis users no less likely to be motivated or able to enjoy life’s pleasure

Credit: RODNAE Productions

Cannabis users also show no difference in motivation for rewards, pleasure taken from rewards, or the brain’s response when seeking rewards, compared to non-users.

Cannabis is the third most commonly used controlled substance worldwide, after alcohol and nicotine. A 2018 report from the NHS Digital Lifestyles Team stated that almost one in five (19%) of 15-year-olds in England had used cannabis in the previous 12 months, while in 2020 the National Institute on Drug Abuse reported the proportion in the United States to be 28% of 15-16-year-olds.

A common stereotype of cannabis users is the ‘stoner’ – think Jesse Pinkman in Breaking Bad, The Dude in The Big Lebowski, or, more recently, Argyle in Stranger Things. These are individuals who are generally depicted as lazy and apathetic.

At the same time, there has been considerable concern of the potential impact of cannabis use on the developing brain and that using cannabis during adolescence might have a damaging effect at an important time in an individual’s life.

A team led by scientists at UCL, the University of Cambridge and the Institute of Psychiatry, Psychology & Neuroscience at King’s College London carried out a study examining whether cannabis users show higher levels of apathy (loss of motivation) and anhedonia (loss of interest in or pleasure from rewards) when compared to controls and whether they were less willing to exert physical effort to receive a reward. The research was part of the CannTEEN study.

Global fish stocks can’t rebuild if nothing is done to halt climate change and overfishing

Photo by Hiroko Yoshii on Unsplash

Global fish stocks will not be able to recover to sustainable levels without strong actions to mitigate climate change, a new study has projected.

Researchers at UBC, the Stanford Center for Ocean Solutions and University of Bern projected the impact that different global temperature increases and ranges of fishing activity would have on biomass, or the amount of fish by weight in a given area, from 1950 to 2100. Their simulations suggest that climate change has reduced fish stocks in 103 of 226 marine regions studied, including Canada, from their historical levels. These stocks will struggle to rebuild their numbers under projected global warming levels in the 21st century.

“More conservation-oriented fisheries management is essential to rebuild over-exploited fish stocks under climate change. However, that alone is not enough,” says lead author Dr. William Cheung, professor in the Institute for the Oceans and Fisheries (IOF). “Climate mitigation is important for our fish stock rebuilding plans to be effective”

The research team, including co- author Dr. Colette Wabnitz of Stanford Centre for Ocean Solutions, used computer models to find out the climate change levels at which over-exploited fish stocks cannot rebuild. Currently, the world is on track to exceed 1.5 degrees of warming relative to preindustrial levels and approach two degrees in the next few decades, says Dr. Cheung.

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