. Scientific Frontline

Friday, September 29, 2023

Ancient plant wax reveals how global warming affects methane in Arctic lakes

A 2014 field photo from Wax Lips Lake on northwest Greenland with the Greenland Ice Sheet in the background and three of the study authors (Jamie McFarlin, Everett Lasher, Yarrow Axford).
Photo Credit: Alex P. Taylor

By studying fossils from ancient aquatic plants, Northwestern University and University of Wyoming (UW) researchers are gaining a better understanding of how methane produced in Arctic lakes might affect — and be affected by — climate change.

In a new study, the researchers examined the waxy coatings of leaves preserved as organic molecules within sediment from the early-to-middle Holocene, a period of intense warming that occurred due to slow changes in Earth’s orbit 11,700 to 4,200 years ago. These wax biomarkers — which were once a part of common aquatic brown mosses — were preserved in sediment buried beneath four lakes in Greenland.

Monitoring changes in methane levels

By studying these biomarkers, the researchers discovered that past warming during the middle Holocene caused lakes across a wide range of Greenland’s climates to generate methane. Because methane is a more potent greenhouse gas than carbon dioxide, any changes in methane production with warming are important to understand.

New study shows signs of early creation of modern human identities

SapienCE researchers have publiched a new study which provides vital information about how and when we may have started developing modern human identities. Image showing excavation at Blombos Cave, South Africa.
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Photo Credit: UiB, SapienCE

The study, which is newly published in the Journal of Human Evolution, confirms previous scant evidence, and supports a multistep evolutionary scenario for the culturalization of the human body.

Eye-catching shells made into ornaments

The new study is conducted by Francesco d'Errico, Karen Loise van Niekerk, Lila Geis and Christopher Stuart Henshilwood. The significant findings provide vital information about how and when we may have started developing modern human identities.

“The discovery of eye-catching unmodified shells with natural holes from 100 to 73 ka confirms previous scant evidence that marine shells were collected, taken to the site and, in some cases, perhaps worn as personal ornaments before a stage in which shells belonging to selected species were systematically, and intentionally perforated with suitable techniques to create composite beadworks”, van Niekerk says.

Similar shells have been found in North Africa, other sites in South Africa and the Mediterranean Levant, which means that the argument is supported by evidence from other sites, not just Blombos Cave.

Small but mighty new gene editor

Structural analysis and deep mutational scanning (DMS) of AsCas12f. The team used cryogenic electron microscopy, a method to look at the structure of biological molecules in high-resolution, to analyze AsCas12f and engineer their new version. The DMS “heatmap” illustrates how all single mutations affected genome-editing activity. Blue squares indicate an undesirable mutation, while red ones represent desirable changes. The darker the color, the greater the effect.
Illustration Credit: © Hino et al. 2023

A new CRISPR-based gene-editing tool has been developed which could lead to better treatments for patients with genetic disorders. The tool is an enzyme, AsCas12f, which has been modified to offer the same effectiveness but at one-third the size of the Cas9 enzyme commonly used for gene editing. The compact size means that more of it can be packed into carrier viruses and delivered into living cells, making it more efficient. Researchers created a library of possible AsCas12f mutations and then combined selected ones to engineer an AsCas12f enzyme with 10 times more editing ability than the original unmutated type. This engineered AsCas12f has already been successfully tested in mice and has the potential to be used for new, more effective treatments for patients in the future.

By now you have probably heard of CRISPR, the gene-editing tool which enables researchers to replace and alter segments of DNA. Like genetic tailors, scientists have been experimenting with “snipping away” the genes that make mosquitoes malaria carriers, altering food crops to be more nutritious and delicious, and in recent years begun human trials to overcome some of the most challenging diseases and genetic disorders. The potential of CRISPR to improve our lives is so phenomenal that in 2020, researchers Jennifer Doudna and Emmanuelle Charpentier, who developed the most precise version of the tool named CRISPR-Cas9, were awarded the Nobel Prize in chemistry.

A lethal parasite’s secret weapon: infecting non-immune cells

Photomicrograph of spleen tissue showing the presence of numerous Leishmania donovani parasites in the amastigote form they take after infecting a host.
Image Credit: Centers for Disease Control and Prevention

The organisms that cause visceral leishmaniasis, a potentially deadly version of the parasitic disease that most often affects the skin to cause disfiguring disease, appear to have a secret weapon, new research suggests: They can infect non-immune cells and persist in those uncommon environments. 

Researchers found the Leishmania donovani parasites in blood-related stem cells in the bone marrow of chronically infected mice – precursor cells that can regenerate all types of cells in the blood-forming system. The finding may help explain why some people who develop visceral leishmaniasis, which is fatal if left untreated, often also have blood disorders such as anemia. 

Identifying these cells and other unexpected locations in which these parasites live improve scientists’ understanding of the disease and may lead to new treatment options, said senior study author Abhay Satoskar, professor of pathology in The Ohio State University College of Medicine. 

A new bioinfomatics pipeline solves a 50-year-old blood group puzzle

Photo Credit: Belova59

Currently, a lot is known about which genes are responsible for our individual blood groups, however not much is understood about how and why the levels of the blood group molecules differ between one person to another. This can be important for blood transfusion safety. Now a research group at Lund University in Sweden has developed a toolbox that finds the answer – and in doing so, has solved a 50-year-old mystery.

The study was published recently in Nature Communications.

For the past 30 years, the research group in Lund has studied the genetic basis of our many blood groups and their research has laid the foundation for six new blood group systems. On the surface of the red blood cell are found proteins and carbohydrates that are very similar between people.

However, small differences in these molecules have been shown to be due to genetic variants that encode what we know as blood group antigens. What has not been understood until now is why people with the same blood group can have different amounts of a certain blood group antigen on their red blood cells.

Study shows that Basophil Activation Test (BAT) is key for predicting allergic reactions

Photo Credit: Jakub Kapusnak

Researchers have found that BAT was the best biomarker to predict severity and threshold of allergic reactions to eggs

New research, published in the European Journal of Allergy and Clinical Immunology, has found that Basophil Activation Test (BAT) can be used to better detect allergies and predict the severity of allergic reactions than traditional predictions made via clinical criteria.

The MRC-funded Basophil Activation Test to Diagnose Food Allergy (BAT2) Study, led by Professor Alexandra Santos of King’s College London, aimed to identify if BAT testing could be used to predict the risk of severe allergic reactions and/or low threshold of reactivity.

For the study one hundred and fifty children, recruited from specialized tertiary Pediatric Allergy clinics in London, underwent double-blind placebo-controlled food challenge to determine possible allergies to baked egg. Patients who passed this underwent a similar process but this time with loosely cooked egg, with the severity of allergic reactions classified following Practall guidelines.

Intense Lasers Shine new Light on the Electron Dynamics of Liquids

An intense laser pulse (in red) hits a flow of water molecules, inducing an ultrafast dynamics of the electrons in the liquid.
Illustration Credit: ©J. Harms, MPSD

The behavior of electrons in liquids plays a big role in many chemical processes that are important for living things and the world in general. For example, slow electrons in liquid have the capacity to cause disruptions in the DNA strand.

But electron movements are extremely hard to capture because they take place within attoseconds: the realm of quintillionths of a second. Since advanced lasers now operate at these timescales, they can offer scientists glimpses of these ultrafast processes via a range of techniques.

An international team of researchers has now demonstrated that it is possible to probe electron dynamics in liquids using intense laser fields and to retrieve the electron's mean free path - the average distance an electron can travel before colliding with another particle.

"We found that the mechanism by which liquids emit a particular light spectrum, known as the high-harmonic spectrum, is markedly different from the ones in other phases of matter like gases and solids," said Zhong Yin from Tohoku University's International Center for Synchrotron Radiation Innovation Smart (SRIS) and co-first author of the paper. "Our findings open the door to a deeper understanding of ultrafast dynamics in liquids."

Good news for the world’s rarest marine dolphin?

Māui dolphins.
Photo Credit: University of Auckland/Department of Conservation

The tiny population – only about 54 Māui dolphins remain – lives off the west coast of the North Island.

Once seen from Cook Strait to north of Kaipara, the dolphins’ range is now considerably smaller, with most sightings between Muriwai and Raglan.

The creatures' median age dropped by about a year over the course of a decade, according to research from the University of Auckland – Waipapa Taumata Rau, Oregon State University and University of California Los Angeles.

It could be good news: a population with younger dolphins will produce more calves than an older population, ultimately increasing the population size, which is vital for the dolphins' future.

“The population may be getting younger because individuals born after 2008, the year a marine sanctuary was introduced off the west coast of the North Island, have better chances of survival, since they are less likely to be accidentally caught in fishing nets,” suggests Professor Rochelle Constantine.

However, it’s also possible that older dolphins aren’t living to expected maximum ages of about 20 years.

Soil bacteria prevail despite drought conditions

ClimGrass, the field experiment in Styria, in which drought is simulated in combination with future climate conditions.
Photo Credit: Markus Herndl, HBLFA Raumberg-Gumpenstein

Recent research uncovers the resilience of certain soil microorganisms in the face of increasing drought conditions. While many bacteria become inactive during dry spells, specific groups persist and even thrive. This study, conducted by the Centre for Microbiology and Environmental Systems Science (CeMESS) at the University of Vienna, offers ground-breaking insights into bacterial activity during drought periods, with implications for agriculture and our understanding of climate change impacts. The study has been published in the renowned scientific journal Nature Communications.

The images of the parched Po Valley in 2022 and this year's forest fires in Greece underscore the reality of extreme droughts – not just as news headlines but as immediate threats. The repercussions for humans and plant life are evident: crop failures, withered meadows, and water rationing. However, the impact of drought on soil microorganisms remains hidden from the naked eye.

Soil microorganisms play a pivotal role in ecosystems. They contribute to soil fertility, assist plants in nutrient absorption, and determine whether soils store or release CO2, thereby influencing climate change trajectories. Until now, measuring the activity of microorganisms in dry soils and identifying which species remain active was challenging. Thanks to a novel method developed by scientists at the University of Vienna, bacterial activity during drought periods can now be observed.

Giant molecular rotors operate in solid crystal

Artistic depiction of a giant rotor molecule rotating in the solid state.
Illustration Credit: Rempei Ando, et al. Angewandte Chemie International Edition.

Concave, umbrella-like metal complexes provide space to enable the largest molecular rotor operational in the solid-state.

Solid materials are generally known to be rigid and unmoving, but scientists are turning this idea on its head by exploring ways to incorporate moving parts into solids. This can enable the development of exotic new materials such as amphidynamic crystals—crystals which contain both rigid and mobile components—whose properties can be altered by controlling molecular rotation within the material. 

A major challenge to achieving motion in crystals—and in solids in general—is the tightly packed nature of their structure. This restricts dynamic motion to molecules of a limited size. However, a team led by Associate Professor Mingoo Jin from the Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University has set a size record for such dynamic motion, demonstrating the largest molecular rotor shown to be operational in the solid-state.

A molecular rotor consists of a central rotating molecule that is connected by axis molecules to stationary stator molecules, similar to the way that a wheel and axle are connected to a car frame. Such systems have been previously reported, but the crystalline material in this study features an operational rotor consisting of the molecule pentiptycene, which is nearly 40% larger in diameter than previous rotors in the solid-state, marking a significant advancement. 

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