Earth

Among the most extreme planets discovered beyond the edges of our solar system are lava planets: fiery hot worlds that circle so close to their host star that some regions are likely oceans of molten lava. According to scientists from McGill University, York University, and the Indian Institute of Science Education, the atmosphere and weather cycle of at least one such exoplanet is even stranger, featuring the evaporation and precipitation of rocks, supersonic winds that rage over 5000 km/hr, and a magma ocean 100 km deep.

In a study published in Monthly Notices of the Royal Astronomical Society, the scientists use computer simulations to predict the conditions on K2-141b, an Earth-size exoplanet with a surface, ocean, and atmosphere all made up of the same ingredients: rocks. The extreme weather forecasted by their analysis could permanently change the surface and atmosphere of K2-141b over time.

"The study is the first to make predictions about weather conditions on K2-141b that can be detected from hundreds of light years away with next-generation telescopes such as the James Webb Space Telescope," says lead author Giang Nguyen, a PhD student at York University who worked under the supervision of McGill University Professor Nicolas Cowan on the study.

Two-thirds of the exoplanet faces endless daylight

In analyzing the illumination pattern of the exoplanet, the team discovered that about two-thirds of K2-141b faces perpetual daylight - rather than the illuminated hemisphere we are used to on Earth. K2-141b belongs to a subset of rocky planets that orbit very close to their star. This proximity keeps the exoplanet gravitationally locked in place, meaning the same side always faces the star.

The night side experiences frigid temperatures of below -200 C. The day side of the exoplanet, at an estimated 3000 C, is hot enough to not only melt rocks but vaporize them as well, ultimately creating a thin atmosphere in some areas. "Our finding likely means that the atmosphere extends a little beyond the shore of the magma ocean, making it easier to spot with space telescopes," says Nicolas Cowan, a professor in the Department of Earth & Planetary Sciences at McGill University.

Like Earth's water cycle, only with rocks

Remarkably, the rock vapour atmosphere created by the extreme heat undergoes precipitation. Just like the water cycle on Earth, where water evaporates, rises into the atmosphere, condenses, and falls back as rain, so too does the sodium, silicon monoxide, and silicon dioxide on K2-141b. On Earth, rain flows back into the oceans, where it will once more evaporate and the water cycle is repeated. On K2-141b, the mineral vapour formed by evaporated rock is swept to the frigid night side by supersonic winds and rocks "rain" back down into a magma ocean. The resulting currents flow back to the hot day side of the exoplanet, where rock evaporates once more.

Still, the cycle on K2-141b is not as stable as the one on Earth, say the scientists. The return flow of the magma ocean to the day side is slow, and as a result they predict that the mineral composition will change over time - eventually changing the very surface and atmosphere of K2-141b.

"All rocky planets­, including Earth, started off as molten worlds but then rapidly cooled and solidified. Lava planets give us a rare glimpse at this stage of planetary evolution," says Professor Cowan of the Department of Earth and Planetary Sciences.

The next step will be to test if these predictions are correct, say the scientists. The team now has data from the Spitzer Space Telescope that should give them a first glimpse at the day-side and night-side temperatures of the exoplanet. With the James Webb Space Telescope launching in 2021, they will also be able to verify whether the atmosphere behaves as predicted.

WASHINGTON, November 3, 2020 -- The ongoing COVID-19 pandemic has led many researchers to study airborne droplet transmission in different conditions and environments. The latest studies are starting to incorporate important aspects of fluid physics to deepen our understanding of viral transmission.

In a new paper in Physics of Fluids, by AIP Publishing, researchers from A*STAR's Institute of High Performance Computing conducted a numerical study on droplet dispersion using high fidelity air flow simulation. The scientists found a single 100-micrometer cough droplet under wind speed of 2 meters per second can travel up to 6.6 meters and even further under dry air conditions due to droplet evaporation.

"In addition to wearing a mask, we found social distancing to be generally effective, as droplet deposition is shown to be reduced on a person who is at least 1 meter from the cough," said author Fong Yew Leong.

The researchers used computational tools to solve complex mathematical formulations representing air flow and the airborne cough droplets around human bodies at various wind speeds and when impacted by other environmental factors. They also assessed the deposition profile on a person at a certain proximity.

A typical cough emits thousands of droplets across a wide size range. The scientists found large droplets settled on the ground quickly due to gravity but could be projected 1 meter by the cough jet even without wind. Medium-sized droplets could evaporate into smaller droplets, which are lighter and more easily borne by the wind, and these traveled further.

The researchers offer a more detailed picture of droplet dispersion as they incorporated the biological considerations of the virus, such as the nonvolatile content in droplet evaporation, into the modelling of the airborne dispersion of droplets.

"An evaporating droplet retains the nonvolatile viral content, so the viral loading is effectively increased," said author Hongying Li. "This means that evaporated droplets that become aerosols are more susceptible to be inhaled deep into the lung, which causes infection lower down the respiratory tract, than larger unevaporated droplets."

These findings are also greatly dependent on the environmental conditions, such as wind speed, humidity levels, and ambient air temperature, and based on assumptions made from existing scientific literature on the viability of the COVID-19 virus.

While this research focused on outdoor airborne transmission in a tropical context, the scientists plan to apply their findings to assess risk in indoor and outdoor settings where crowds gather, such as conference halls or amphitheaters. The research could also be applied to designing environments that optimize comfort and safety, such as hospital rooms that account for indoor airflow and airborne pathogen transmission.

Durham, NC -Each year ligament injuries sideline thousands of athletes and regular citizens. Recovery is long and painful, and sometimes a return to full function is never realized due to scar formation - a factor that makes ligament injuries prone to further damage. A new exosomes study released today in STEM CELLS may lead to a welcomed solution in the future.

This study demonstrates how exosomes, sacs of cell membrane in the body that shuttle proteins and genetic information between cells, and exosome-educated macrophages (EEMs), a type of white blood cell that typically kills microorganisms and removes dead cells, but also could stimulate the action of other immune system cells, can promote ligament healing and reduce scarring.

Last year the team behind this study, researchers at the University of Wisconsin-Madison (UW-Madison), released another study (also published in STEM CELLS) that showed how treating an Achilles tendon with EEMs reduces inflammation and improves tendon strength. The EEMs were generated by exposing CD14+ macrophages to mesenchymal stromal cell (MSC) derived exosomes.

"Our previous study was done on a mouse model," said Ray Vanderby, Ph.D., professor of orthopedics and rehabilitation at UW-Madison. He and Peiman Hematti, M.D., from UW-Madison's Department of Medicine, are corresponding authors on both of these studies. "While the results were superior when compared to treatment with MSCs, the functional/mechanical benefit of the exosomes was not as obvious as with the EEMs. This led us to our current study goals."

First, the researchers wanted to reproduce the healing effects of EEMs in a different rodent model - a rat medial collateral ligament (MCL), which is a ligament that runs along the edge of the knee. "We hypothesized the EEM treatment would reduce inflammation and accelerate ligament healing, similar to our previous tendon results," Dr. Vanderby said.

Secondly, they wanted to study the effects of exosome therapy on the rats' MCL injuries, hypothesizing that MSC-derived exosomes could also improve ligament healing and reduce scar formation.

When the results came in, they supported the team's speculation that EEMs did, indeed, improve rat MCL function and reduced the M1/M2 macrophage ratio, too. (M1 macrophages protect against bacteria and viruses, while M2 macrophages focus on wound healing and tissue repair.)

The exosomes also elicited a biological response - most notably, an increase in collagen and a reduction in scarring. "The ability of exosomes to reduce scar formation and upregulate collagen type expression has been documented in tendon healing models, but to our knowledge this is the first study to report this in ligaments," Dr. Vanderby said.

"This study is an exciting advance in the field of MSC-derived exosomes," said Dr. Jan Nolta, Editor-in-Chief of STEM CELLS "the demonstration by this excellent group that exosome-educated macrophages can play such a major role in both tendon and ligament healing has exciting potential for improving the trajectory of healing of human athletic injuries."

The investigators now question whether, in addition to promoting healing in ligament- and tendon-related injuries, EEMs and exosomes might be applied to other scarring debilities. Of special interest to this group is how they might be used to treat a wide range of degenerative and sport-related orthopedic conditions. However, EEMs and exosome could be investigated in a wide range of other applications, too, such as radiation damage to the bone marrow, another area of special interest to Dr. Hematti, as a bone marrow transplant physician.

"EEMs and exosomes each have attractive characteristics as therapeutics," Dr. Hematti noted. "As a cell therapy, EEMs will not proliferate or differentiate to undesirable cell types, which remains a concern for many stem cell therapies. Moreover, EEMs could be generated from a patient's own monocytes using off-the-shelf exosomes, resulting in a faster and more facile process compared to autologous MSCs. Alternatively, exosome therapy could be a cell free, shelf-stable therapeutic to deliver biologically active components."

"Altogether, we believe our studies' results support the use of EEMs and/or exosomes to improve ligament healing by modulating inflammation and tissue remodeling," Dr. Vanderby concluded.

Using artificial intelligence, UCPH researchers have solved a problem that until now has been the stumbling block for important protein research into the dynamics behind diseases such as cancer, Alzheimer's and Parkinson's, as well as in the development of sustainable chemistry and new gene-editing technologies.

It has always been a time-consuming and challenging task to analyse the huge datasets collected by researchers as they used microscopy and the smFRET technique to see how proteins move and interact with their surroundings. At the same time the task required a high level of expertise. Hence, the proliferation of stuffed servers and hard drives. Now researchers at the Department of Chemistry, Nano-Science Center, Novo Nordisk Foundation Center for Protein Research and the Niels Bohr Institute, University of Copenhagen, have developed a machine learning algorithm to do the heavy lifting.

"We used to sort data until we went loopy. Now our data is analysed at the touch of button. And, the algorithm does it at least as well or better than we can. This frees up resources for us to collect more data than ever before and get faster results," explains Simon Bo Jensen, a biophysicist and PhD student at the Department of Chemistry and the Nano-Science Center.

The algorithm has learned to recognize protein movement patterns, allowing it to classify data sets in seconds -- a process that typically takes experts several days to accomplish.

"Until now, we sat with loads of raw data in the form of thousands of patterns. We used to check through it manually, one at a time. In doing so, we became the bottleneck of our own research. Even for experts, conducting consistent work and reaching the same conclusions time and time again is difficult. After all, we're humans who tire and are prone to error," says Simon Bo Jensen.

Just a second's work for the algorithm

The studies about the relationship between protein movements and functions conducted by the UCPH researchers is internationally recognized and essential for understanding how the human body functions. For example, diseases including cancer, Alzheimer's and Parkinson's are caused by proteins clumping up or changing their behaviour. The gene-editing technology CRISPR, which won the Nobel Prize in Chemistry this year, also relies on the ability of proteins to cut and splice specific DNA sequences. When UCPH researchers like Guillermo Montoya and Nikos Hatzakis study how these processes take place, they make use of microscopy data.

"Before we can treat serious diseases or take full advantage of CRISPR, we need to understand how proteins, the smallest building blocks, work. This is where protein movement and dynamics come into play. And this is where our tool is of tremendous help," says Guillermo Montoya, Professor at the Novo Nordisk Foundation Center for Protein Research.

Attention from around the world

It appears that protein researchers from around the world have been missing just such a tool. Several international research groups have already presented themselves and shown an interest in using the algorithm.

"This AI tool is a huge bonus for the field as a whole because it provides common standards, ones that weren't there before, for when researchers across world need to compare data. Previously, much of the analysis was based on subjective opinions about which patterns were useful. Those can vary from research group to research group. Now, we are equipped with a tool that can ensure we all reach the same conclusions," explains research director Nikos Hatzakis, Associate Professor at the Department of Chemistry and Affiliate Associate Professor at the Novo Nordisk Foundation Center for Protein Research.

He adds that the tool offers a different perspective as well:

"While analysing the choreography of protein movement remains a niche, it has gained more and more ground as the advanced microscopes needed to do so have become cheaper. Still, analysing data requires a high level of expertise. Our tool makes the method accessible to a greater number of researchers in biology and biophysics, even those without specific expertise, whether it's research into the coronavirus or the development of new drugs or green technologies."

Many diseases caused by common plant viruses reduce the crops of important food plants. In the worst case, potato viruses, among others, can destroy as much as 80% of crops on infected fields.

Plants are not entirely defenceless against viruses, although they lack an immune system like the one found in humans. For plant cells, the primary defence mechanism against viral infections is gene silencing. By utilising the mechanism, plant cells identify the foreign genetic material originating in the virus and cut it up into small pieces.

"In turn, these bits of the genome guide plant cell proteins to identify and destroy viral genomes. As a result, the production of viral proteins ends, which is interpreted as 'silencing' of the viral genes. A successful defensive response prevents the virus from spreading in the plant," says Docent Kristiina Mäkinen from the Faculty of Agriculture and Forestry, University of Helsinki.

Viruses can hijack the plant's defence system

At the same time, viruses too have means with which to resist and subvert the host plant's defence mechanisms. A research group specialised in plant virology, led by Mäkinen, investigates the interaction between potato virus A and host plant proteins. Mäkinen and her group find one viral protein particularly interesting, as it is directed against the plant's defence system.

"This protein is able to not only block gene silencing, but also to harness the factors involved in the process to serve both its viral replication and the formation of new viral particles. In other words, the virus forces, as it were, the plant's defence system to go against its intended purpose, in favour of the pathogen."

Genes play a part in resistance - Modern plant breeding techniques needed

Studies on plants that are naturally resistant to viruses have shown that their resistance is often based on mutations in the plant's genome that block interaction between viral and plant proteins. To employ these mutations in plant breeding, University Researcher Maija Pollari considers it necessary to start utilising modern plant breeding techniques.

"For instance, the CRISPR/Cas9 technique, which was just awarded the Nobel Prize in Chemistry, makes it possible to target anti-viral mutations in a precise location in the plant genome. This is a great stride forward compared to traditional plant breeding, which relies on the use of mutagenic chemicals and radioactive radiation," Pollari adds.

The interactions between plant and viral proteins discovered by Kristiina Mäkinen's research group offer new targets for breeding resistance against the potato virus in host plants. The researchers' aim is to identify a component in the plant proteins through which they come into contact with viral proteins.

"When proteins are modified so that the interaction is blocked, the plant's gene silencing mechanism may regain the upper hand over the virus. Strains resistant to viruses used in cultivation reduce losses caused by viral diseases and, consequently, improve yields. Furthermore, it's likely that the chemical burden of the environment is alleviated, as the amount of chemicals used in preventing aphids is reduced," notes Kristiina Mäkinen.

The UPV/EHU's research group OPIK, Social Determinants of Health and Demographic Change, is a multidisciplinary group comprising research personnel in the field of social and health sciences; it explores the social factors influencing health and disease in the population, social inequalities in health and the policies that have the potential to modify these social determinants in the interests of improving the health of the population.

Gender is a significant determining factor in mental health and in how it is managed by the healthcare services, according to recent studies conducted by this group and based on health questionnaires completed in the Basque Autonomous Community (2018) and in Spain (2017), and on the Spanish sample corresponding to the European Health Survey (2014). What stands out in the analysis of these three databases is the higher prevalence of poor mental health among women of all ages and across all social groups; in addition, there is a multiplier effect due to the accumulation of experiences of inequality. This reality also appears to be unequal in terms of the age and socioeconomic level of the patients.

The PhD holder in public health Amaia Bacigalupe, one of the authors of the study, asserts that "women are more frequently diagnosed with depression and anxiety and the taking of prescribed psychotropic drugs is also significantly higher, even if there is no difference with men with respect to mental health equality, diagnoses and frequency of visits to healthcare centres. All this could point to the existence of a medicalisation process of mental health in women, but interpreting its origin is complex since the processes involving the high prevalence of diagnosis and overprescription undoubtedly play a role, but maybe also due to infra-diagnosis and lower prescription rates in men". Bacigalupe adds that these aspects should be tackled in greater depth in future studies.r

Reducing gender inequalities

The research group highlights the fact that reducing gender inequalities in mental health will need to be the result of policy intervention on various levels. "There is a clear relationship between the degree of gender inequality in society and gender inequalities in mental health," says Amaia Bacigalupe, "so all those policies designed to combat the discrimination endured by women on the labour market, in the responsibility for domestic and care work, in the use of time and, generally, relating to those that empower women on the basis of their greater political representation and making them more socially visible, will exert a positive effect on the reduction in mental inequalities between men and women".

Another aspect highlighted in the study is the need to make commitments starting from an institutional level and geared towards curbing the medicalisation of everyday malaise from a clear gender perspective. "In the field of mental health in which the medicalisation of malaise is especially common, far from addressing the cause of the problem, some problems of a social origin end up receiving psychiatric or psychological treatment," said the researcher in the Department of Sociology 2 at the UPV/EHU.

According to the study, it would also be necessary to encourage spaces for reflection in the clinical setting designed to help to collectively deconstruct certain aspects that have become natural in gender binarism and which have underpinned the definitions of psychopathology and its current treatment. Bacigalupe also says that "the actual incorporation into clinical practice of the biopsychosocial model, as well as the implementing of strategies to promote health and emotional well-being from a community health approach based on assets, could prevent the over-pathologization and over-medicalization of everyday malaise once a global view of how the social context influences health is acquired".

How biodiversity is generated and maintained are central questions in science, which are becoming increasingly important for our quality of life. How do similar species coexist in a system? Which ones will dominate or be excluded? Will the system succumb to invasion by outsiders? Can we predict these interactive dynamics in systems with many different species? Simulations and statistical approaches are typically adopted to answer these questions, but the limited predictions they offer prompted Erida Gjini, principal investigator at Instituto Gulbenkian de Ciência, in collaboration with Sten Madec, from the University of Tours, in France, to explore a deeper mathematical route and uncover the general rules that describe such systems.

The two researchers used the system of microbial transmission between hosts as the basis of their theoretical study. In this type of system, each species colonizing the host can alter the local environment and make it better or worse for co-colonization by another species. If made better, it is described as pairwise facilitation; if made worse, it reflects pairwise competition. This study proposes a framework that addresses what is the final outcome in a network of many pairwise interactions and how its members "engineer" together their coexistence.

"In the beginning we did not know how the pairwise competition or facilitation between all interacting members translated into the global dynamics of the system. We were dealing with many equations and their number rose quadratically with the number of species we considered in our model. For example, for 10 species we would have more than 100 equations to deal with", stated Erida Gjini. The mathematical technique of time-scale separation offered an advantage here, since it allows the separation of the variables that change faster from the ones that change slower.

"Thanks to this method we uncovered a simple equation that belongs to the family of the replicator equations (widely used in evolutionary game theory), which governs frequency dynamics between species in our model. This type of equations captures the essence of the competition between multiple strategies in a multi-player game and how their success changes over time. Surprisingly, we find it here, emerging from the matrix of 'social' interactions", explains Erida Gjini. With these results, it becomes clear that global dynamics of the system can be predicted entirely from the type and quality of pairwise interactions.

"We believe this will change the way people study multi-type communities, beyond epidemiology, which was the initial motivation for this work. On a more fundamental level, the mathematical language of this work ultimately conveys that we do not live alone, but are embedded in a network of inter-dependencies with others, where individual success depends on proximal connections, but also on the global emerging context", highlight the authors. This framework brings analytical and computational advantages for studying and interpreting high-dimensional interacting systems, especially in what regards their stability and evolution, establishing co-colonization as an important route to coexistence and biodiversity.

Cells can evolve specialised functions under a much broader range of conditions than previously thought, according to a study published today in eLife.

The findings, originally posted on bioRxiv*, provide new insight about natural selection, and help us understand how and why common multicellular life has evolved so many times on Earth.

Life on Earth has been transformed by the evolution of multicellular life forms. Multicellularity allowed organisms to develop specialised cells to carry out certain functions, such as being nerve cells, skin cells or muscle cells. It has long been assumed that this specialisation of cells will only occur when there are benefits. For example, if by specialising, cells can invest in two products A and B, then evolution will only favour specialisation if the total output of both A and B is greater than that produced by a generalist cell. However, to date, there is little evidence to support this concept.

"Rather than each cell producing what it needs, specialised cells need to be able to trade with each other. Previous work suggests that this only happens as long as the overall group's productivity keeps increasing," explains lead author David Yanni, PhD student at Georgia Institute of Technology, Atlanta, US. "Understanding the evolution of cell-to-cell trade requires us to know the extent of social interactions between cells, and this is dictated by the structure of the networks between them."

To study this further, the team used network theory to develop a mathematical model that allowed them to explore how different cell network characteristics affect the evolution of specialisation. They separated out two key measurements of cell group fitness - viability (the cells' ability to survive) and fecundity (the cells' ability to reproduce). This is similar to how multicellular organisms divide labour in real life - germ cells carry out reproduction and somatic cells work to ensure the organism survives.

In the model, cells can share some of the outputs of their investment in viability with other cells, but they cannot share outputs of efforts in reproduction. So, within a multicellular group, each cell's viability is the return on its own investment and that of others in the group, and gives an indication of the group's fitness.

By studying how the different network structures affected the group fitness, the team came to a surprising conclusion: they found that cell specialisation can be favoured even if this reduces the group's total productivity. In order to specialise, cells in the network must be sparsely connected, and they cannot share all the products of their labour equally. These match the conditions that are common in the early evolution of multicellular organisms - where cells naturally share viability and reproduction tasks differently, often to the detriment of other cells in the group.

"Our results suggest that the evolution of complex multicellularity, indicated by the evolution of specialised cells, is simpler than previously thought, but only if a few certain criteria are met," concludes senior author Peter Yunker, Assistant Professor at Georgia Institute of Technology, Atlanta, US. "This contrasts directly to the prevailing view that increasing returns are required for natural selection to favour increased specialisation."

Sensors for forest monitoring are already used to track changes in temperature, humidity and light, as well as the movements of animals and insects through their habitat. They also help to detect and monitor forest fires and can provide valuable data on how climate change and other human activities are impacting the natural world.

However, placing these sensors can prove difficult in large, tall forests, and climbing trees to place them poses its own risks.

Now, researchers at Imperial College London's Aerial Robotics Laboratory have developed drones that can shoot sensor-containing darts onto trees several metres away in cluttered environments like forests. The drones can also place sensors through contact or by perching on tree branches.

The researchers hope the drones will be used in future to create networks of sensors to boost data on forest ecosystems, and to track hard-to-navigate biomes like the Amazon rainforest.

Lead researcher Professor Mirko Kovac, director of the Aerial Robotics Lab from the Department of Aeronautics at Imperial said: "Monitoring forest ecosystems can be difficult, but our drones could deploy whole networks of sensors to boost the amount and precision of environmental and ecological data.

"I like to think of them as artificial forest inhabitants who will soon watch over the ecosystem and provide the data we need to protect the environment."

The drones are equipped with cameras to help identify suitable targets, and a smart material that changes shape when heated to launch the darts, which then stick to the trees. They can also perch on tree branches like birds to collect data themselves, acting as mobile sensors.

The researchers have tested their drones at the Swiss Federal Laboratories for Materials Science and Technology (EMPA) and on trees at Imperial's Silwood Park Campus.

The drones are currently controlled by people: using control units, the researchers watch through the camera lens to select target trees and shoot the darts. The next step is to make the drones autonomous, so that researchers can test how they fare in denser forest environments without human guidance.

Co-author Andre Farhina, of the Department of Aeronautics, said: "There are plenty of challenges to be addressed before the drones can be regularly used in forests, like achieving a careful balance between human input and automated tasks so that they can be used safely while remaining adaptable to unpredictable environments."

Co-author Dr Salua Hamaza, also of the Department of Aeronautics, said: "We aim to introduce new design and control strategies to allow drones to effectively operate in forested environments. Exploiting smart mechanisms and new sensing techniques we can off-load the on-board computation, and create platforms that are energy-efficient and better performing."

Translation is the process by which genetic information is converted into proteins, the workhorses of the cell. Small molecules called transfer RNAs ("tRNAs") play a crucial role in translation; they are the adapter molecules that match codons (the building blocks of genetic information) with amino acids (the building blocks of proteins). Organisms carry many types of tRNAs, each encoded by one or more genes (the "tRNA gene set").

Broadly speaking, the function of the tRNA gene set - to translate 61 types of codons into 20 different kinds of amino acids - is conserved across organisms. Nevertheless, tRNA gene set composition can vary considerably between organisms. How and why these differences arise has been a question of long-standing interest among scientists.

Evolution of a bacterial tRNA set in the lab

Jenna Gallie (Research Group Leader at the Max Planck Institute for Evolutionary Biology) and her team have investigated how the tRNA gene set of the bacterium Pseudomonas fluorescens can evolve, using a combination of mathematical modelling and lab-based experiments.

"We started by removing one type of tRNA from the bacterium's genome, resulting in a bacterial strain that grows slowly. We gave this slow-growing strain the opportunity to improve its growth during a real-time evolution experiment. We saw the strain improve repeatedly and rapidly. The improvement was due to the duplication of large chunks of bacterial genetic information, with each duplication containing a compensatory tRNA gene. Ultimately, the elimination of one tRNA type was compensated by an increase in the amount of a second, different tRNA type." Jenna Gallie said. The duplicated tRNA type can compensate because it is able to perform, at a lower rate, the codon-amino acid matching function of the eliminated tRNA type.

The first direct observation of tRNA gene duplication

Comparisons of tRNA genes in related genomes have previously provided evidence for the duplication of some tRNA genes throughout evolutionary history. The experiments described here provide direct, empirical evidence that tRNA gene sets can evolve through duplication events.

Inspired by a parasitic worm that digs its sharp teeth into its host's intestines, Johns Hopkins researchers have designed tiny, star-shaped microdevices that can latch onto intestinal mucosa and release drugs into the body.

David Gracias, Ph.D., a professor in the Johns Hopkins University Whiting School of Engineering, and Johns Hopkins gastroenterologist Florin M. Selaru, M.D., director of the Johns Hopkins Inflammatory Bowel Disease Center, led a team of researchers and biomedical engineers that designed and tested shape-changing microdevices that mimic the way the parasitic hookworm affixes itself to an organism's intestines.

Made of metal and thin, shape-changing film and coated in a heat-sensitive paraffin wax, "theragrippers," each roughly the size of a dust speck, potentially can carry any drug and release it gradually into the body.

The team published results of an animal study this week as the cover article in the journal Science Advances.

Gradual or extended release of a drug is a long-sought goal in medicine. Selaru explains that a problem with extended-release drugs is they often make their way entirely through the gastrointestinal tract before they've finished dispensing their medication.

"Normal constriction and relaxation of GI tract muscles make it impossible for extended-release drugs to stay in the intestine long enough for the patient to receive the full dose," says Selaru, who has collaborated with Gracias for more than 10 years. "We've been working to solve this problem by designing these small drug carriers that can autonomously latch onto the intestinal mucosa and keep the drug load inside the GI tract for a desired duration of time."

Thousands of theragrippers can be deployed in the GI tract. When the paraffin wax coating on the grippers reaches the temperature inside the body, the devices close autonomously and clamp onto the colonic wall. The closing action causes the tiny, six-pointed devices to dig into the mucosa and remain attached to the colon, where they are retained and release their medicine payloads gradually into the body. Eventually, the theragrippers lose their hold on the tissue and are cleared from the intestine via normal gastrointestinal muscular function.

Gracias notes advances in the field of biomedical engineering in recent years.

"We have seen the introduction of dynamic, microfabricated smart devices that can be controlled by electrical or chemical signals," he says. "But these grippers are so small that batteries, antennas and other components will not fit on them."

Theragrippers, says Gracias, don't rely on electricity, wireless signals or external controls. "Instead, they operate like small, compressed springs with a temperature-triggered coating on the devices that releases the stored energy autonomously at body temperature."

Irvine, Calif., Nov. 3, 2020 -- Employing a strategy known as "population modification," which involves using a CRISPR-Cas9 gene drive system to introduce genes preventing parasite transmission into mosquito chromosomes, University of California researchers have made a major advance in the use of genetic technologies to control the transmission of malaria parasites.

University of California, Irvine postdoctoral researcher Adriana Adolfi, in collaboration with colleagues at UCI, UC Berkeley and UC San Diego, followed up on the group's pioneering effort to develop CRISPR-based gene drive systems for making mosquito vectors resistant to transmitting malaria parasites by increasing gene drive effectiveness in female mosquito progeny.

"This work mitigates a big issue with the first gene drive systems, which is the accumulation of drive-resistant mosquitoes that could still transmit malaria parasites," said UCI vector biologist Anthony James, the Donald Bren Professor of Microbiology & Molecular Genetics and Molecular Biology & Biochemistry, who was a co-primary investigator on the study.

"The second-generation gene drive system described in this paper can be applied to any of the several thousand genes that are essential for insects to survive or reproduce," said UC San Diego Distinguished Professor Ethan Bier, a co-author of the study and science director at the Tata Institute for Genetics and Society. "While it was developed in fruit flies, this system is readily transportable to a broad selection of insect species that serve as vectors for devastating disorders such as Chagas disease, sleeping disease, leishmaniasis and arboviral diseases."

Study results appear in Nature Communications. Link to study: https://www.nature.com/articles/s41467-020-19426-0

They describe a highly efficient second-generation version of the team's original gene drive, developed for the Indo-Pakistani malaria vector mosquito Anopheles stephensi. The 2015 work, published in Proceedings of the National Academy of Sciences, was the first demonstration of a CRISPR-based gene drive in mosquitoes.

In that first study, the gene drive was transmitted to about 99 percent of progeny when the parent in which the gene drive was inserted was a male but only 60 to 70 percent of offspring when the parent in which the gene drive was inserted was a female. A significant number of drive-resistant chromosomes are generated in females; this, in principle, could allow those females to continue to transmit parasites.

Adolfi, lead author of the new study, and collaborators solved the failure to drive efficiently through females by equipping the gene drive with a functional copy of the target gene into which the drive is inserted. Normal function of this target gene is required in this mosquito species for female survival and fertility after she feeds on blood, and its functionality is usually disrupted when the drive system is inserted into the gene.

The resulting female mosquitoes showed strong and consistent drive in a population cage study and negligible production of drive-resistant chromosomes. This strategy of inserting a gene drive into a gene essential for viability or fertility and at the same time including a functional gene that rescues the loss of viability or fertility provides a general solution to drive resistance through females. Also, as with a catalytic converter removing combustion pollution from automobiles, the new system efficiently eliminates genetic errors made in the drive process.

This gene drive system - in combination with genes for blocking parasite transmission - can now be used to design field-ready strains of mosquitoes. Thorough testing is required to demonstrate safety and efficacy before advancing to field testing.

More evidence has emerged to support stricter coastal management, this time focusing on pollution and overfishing in the picturesque tourist waters off Auckland in New Zealand.

A study of common dolphins (Delphinus delphis) in the Hauraki Gulf connects their diet with the prevalence of commercial fishing and water quality - emphasising the need to carefully manage marine parks and surrounding environments to prevent overfishing and extensive nutrient runoff.

Researchers from the Cetacean Ecology Research Group (CERG) at Auckland's Massey University, in collaboration with the Cetacean Ecology Behaviour and Evolution Lab (CEBEL) at Flinders University and the NZ National Institute of Water and Atmospheric Research (NIWA), examined dietary differences between males and females and over time.

Conducted over 13 years, the study published in Marine Ecology Progress examined seasonal variations in feeding habits based on stable isotopes of carbon and nitrogen in skin samples collected from 56 dolphins that had stranded along the coastline of the gulf.

"We found their carbon values declined during the study period (2004-2016), which could be linked to a decrease in primary productivity in the gulf over time, or a change in dolphin prey selection, or both," says lead author Dr Katharina J. Peters, a postgraduate researcher of CERG at Massey University and adjunct member of the CEBEL at Flinders University.

Senior author and CERG research leader, Massey University Associate Professor Karen Stockin, says depletion of prey stock via commercial fishing could be just one of several reasons to cause dolphins to change their diet by shifting their target prey.

Dr Stockin further indicated that shifts in prey distribution as a consequence of climatic change may also be at play and confirmed this warranted further investigation.

The Hauraki Gulf has been in the focus of much research over the past two decades, with a sobering report being released by Auckland Council earlier this year, showing the dire state of this important ecosystem . Among increased commercial fishing, the document reports high nutrient loads and heavy metal contamination in some parts of the gulf.

"We observed increased nitrogen values over the study period, which could be linked to increased urbanisation of the coastal areas, with high levels of terrestrial nitrogen from for example agriculture being washed into the sea."

Researchers also recorded some differences between male and female isotopic values. A change in nitrogen values at a body length of ~160 cm was detected, which may reflect the transition in diet of calves from mother's milk to fish after being weaned.

"They also seem to have a slightly broader diet in autumn-winder compared to spring-summer," Dr Stockin says, "this could reflect that the types of available prey in the gulf change throughout the seasons".

Dolphins are important predators in marine ecosystems and research on their foraging behavior is critical to manage ecosystems in future, say researchers.

Common dolphins are a sentinel species found in tropical and temperate waters globally and are generally opportunistic predators feeding locally on abundant small pelagic schooling fish.

The new Hauraki Gulf data provide an important baseline to detect future changes in the trophic ecology of D. delphis in a coastal ecosystem that is a key habitat for this species in New Zealand, researchers say.

Wellesley, MA -- A new study published in the Journal of Adolescent Health found that checking social media often, viewing emotional or violent videos, and starting to use social media at an early age were significantly related to later bedtimes and fewer hours of sleep on school nights for early adolescents. Parental rules restricting mobile phone and online use before bed and obtaining a smartphone at a later age were associated with increased sleep duration and earlier bedtimes.

"We need to move beyond the sole focus on the amount of time adolescents spend on technologies before bed," said the study's lead author Linda Charmaraman, Ph.D., director of the Youth, Media and Wellbeing Research Lab at the Wellesley Centers for Women (WCW). "Understanding the bedtime habits and online content that negatively affect sleep helps us design more effective interventions for parents and practitioners to encourage healthier social technology use. This study is a first step in that direction."

As part of the Adolescent Social Media Use, Health, and Parental Monitoring Study, Charmaraman and her co-authors surveyed 772 6-8th grade students from four schools in the Northeast U.S. between February and June 2019. The survey asked questions about social media, internet, and phone use, content of websites and social media posts, behaviors within one hour of bedtime, bedtime, sleep duration, and phone/screen restrictions put in place by parents.

Controlling for potential confounding factors such as gender, age, race/ethnicity, two-parent household, and eligibility for free or reduced price lunch, the researchers found that more frequently engaging in checking social media, problematic internet behaviors, fear of missing out (FoMO), problematic digital technology use, and watching more emotional or violent videos were significantly related to later bedtimes and fewer hours of sleep on a typical school night. Participants who acknowledged losing sleep because they couldn't quit online activities went to bed later and slept less. Seeing posts related to a thin ideal weight was significantly associated with reduced sleep, and seeing messages related to drugs/drinking was significantly related to later bedtimes. Watching YouTube videos before sleep was related to later bedtimes and reduced sleep; checking social media before bed was related to later bedtimes. Reading books was the only bedtime behavior associated with an earlier bedtime.

"Reduced sleep is associated with many adverse physical, emotional, and educational outcomes," said Elizabeth B. Klerman, M.D., Ph.D., of the Massachusetts General Hospital, senior author of the study. "The results of this study provide evidence of modifiable factors that negatively affect sleep duration. Individuals (e.g., children, parents, practitioners, teachers) and communities can work to change behaviors that affect sleep."

Beta-blockers could potentially be used to treat COVID-19, according to a new international study by Italian and Australian scientists.

University of South Australia cancer researcher, Dr Nirmal Robinson, working with a team in Naples, has found evidence in animal models that the beta-blocker Propranolol helps suppress the spread of cancer in the lung which has an inflammatory profile very similar to COVID-19.

The scientists have presented their findings in a paper published in Frontiers in Immunology, calling for clinical trials to support their research.

Dr Robinson, Head of the Cellular-Stress and Immune Response Laboratory at the Centre for Cancer Biology, says Propranolol is commonly used to treat heart conditions, anxiety and migraine. Recent clinical trials have shown its effectiveness for other conditions, including cancer.

"Patients with COVID-19 suffer from many abnormalities, including inflammation, because the SARS-CoV-2 virus disrupts the body's immune system. Beta-2 blockers could potentially reduce this inflammation and help rebalance the immune system," Dr Robinson says.

Beta-blockers including Propranolol are medicines that work by temporarily stopping or reducing the body's natural 'fight-or-flight' response. In return, they reduce stress on certain parts of the body, such as the heart and blood vessels in the brain.

They have also been suggested as a treatment option for autoimmune diseases such as rheumatoid arthritis.

"SARS-Cov-2 enters the human cells through the protein ACE2, infecting the lower respiratory tract, causing profound inflammation and multi-organ failure.

Patients with comorbidities, such as high blood pressure, diabetes and heart disease, are at much higher risk," he says.

Other inflammation suppressors, including Tocilizumab (an immunosuppressive drug prescribed for arthritis) and Ruxolitinib (a drug used to treat the rare bone marrow blood cancer, myelofibrosis) have already been used to treat the more serious COVID-19 cases, the researchers say.

"We believe the beta-2-adrenergic pathway should be more deeply investigated as a possible target to reduce the inflammatory symptoms related to COVID-19. The next step is to perform clinical trials to explore an alternative therapy to treat COVID-19, based on the lessons we have learned from cancer," Dr Robinson says.