Tiny nanoparticle could have big impact on patients receiving corneal transplants

Corneal transplants can be the last step to returning clear vision to many patients suffering from eye disease. Each year  more than 184,000 corneal transplantation surgeries are performed annually in the world.

However, rejection rates for the corneal grafts can be as high as 10%. This is largely due to poor patient compliance to the medications, which require frequent administrations of topical eyedrops over a long period of time.

This becomes especially acute when patients show signs of early rejection of the transplanted corneas. When this occurs, patients need to apply topical eyedrops hourly to rescue the corneal grafts from failure.

The tedious process of eyedrop dosing causes a tremendous burden for patients. The resulting noncompliance to medical treatment can lead to even higher graft-rejection rates.

Research by a team  may make the corneal grafts more successful by using nano particles to encapsulate the medication. The novel approach could significantly improve patient compliance, according to a paper recently published in Science Advances titled "Six-month effective treatment of corneal graft rejection."

Each nanoparticle encapsulates a drug called dexamethasone sodium phosphate, one of the most commonly used corticosteroids for various ocular diseases treatment such as ocular inflammation, non-infectious uveitis, macular edema and corneal neovascularization. By using the nanoparticles to control the release of the medicine over time, patients would require only one injection right after the corneal transplantation surgery without the frequent eye drops. These studies have shown that using this method the medication maintains its efficacy for six months on a corneal graft rejection model.

In addition, because the medicine is released slowly and directly where it is most needed, the approach requires much lower doses than current standard eyedrop treatment while providing better efficacy and safety profiles.

Tuo Meng et al, Six-month effective treatment of corneal graft rejection, Science Advances (2023). DOI: 10.1126/sciadv.adf4608

The fast and the fibrous: Developing the muscles you need for speed

Different types of exercise encourage the formation of different types of muscle fibers, or the cells that make up your muscles. Slow twitch muscle fibers support endurance activities like long-distance running, while fast twitch fibers are needed for short, powerful movements such as those involved in heavy weight lifting. Now, researchers in Japan have shed new light on a family of proteins involved in the development of these muscle fiber types.

Research team finds indirect evidence for existence of dark matter surrounding black holes

Dark matter does not emit or reflect light, nor does it interact with electromagnetic forces, making it exceptionally difficult to detect. Nevertheless, a research team has proven that there is a substantial amount of dark matter surrounding black holes. The study results are published in the journal The Astrophysical Journal Letters.

The team selected two nearby black holes (A0620-00 and XTE J1118+480) as research subjects, with both considered as binary systems. That is, each of the black holes has a companion star orbiting it. Based on the orbits of the companion stars, observations indicate that their rates of orbital decay are approximately one millisecond (1ms) per year, which is about 50 times greater than the theoretical estimation of about 0.02ms annually.

To examine whether dark matter exists around black holes, the team applied the "dark matter dynamical friction model"—a theory widely held in academia—to the two chosen binary systems, through computer simulations. The team found that the fast orbital decay of the companion stars precisely matches the data observed.

Notably, this is indirect evidence that dark matter around black holes can generate significant dynamical friction, slowing down the orbital speed of the companion stars.

Man Ho Chan et al, Indirect Evidence for Dark Matter Density Spikes around Stellar-mass Black Holes, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/acaafa

The findings, which verified a theoretical hypothesis formulated in the late 20th century, represent a breakthrough in dark matter research. According to the hypothesis, dark matter close enough to black holes would be swallowed, leaving the remnants to be redistributed. The process ends up forming a "density spike" around the black holes.

ARTEMIS: Advanced Robotic Technology for Enhanced Mobility and Improved Stability

From mutation to arrhythmia: Desmosomal protein breakdown as an underlying mechanism of cardiac disease

Mutations in genes that form the desmosome are the most common cause of the cardiac disease arrhythmogenic cardiomyopathy (ACM), which affects one in 2,000 to 5,000 people worldwide. Researchers  now discovered how a mutation in the desmosomal gene plakophilin-2 leads to ACM. They found that the structural and functional changes in ACM hearts caused by a plakophilin-2 mutation are the result of increased desmosomal protein degradation. The findings of this study, published in Science Translational Medicine on March 22, 2023, further our understanding of ACM and could contribute to the development of new therapies for this disease.

ACM is a progressive and inheritable cardiac disease for which currently no treatments exist to halt its progression. Although patients initially do not experience any symptoms, they are at a higher risk of arrhythmias and resulting sudden cardiac arrest. As the disease progresses, patches of fibrotic and fat tissue form in the heart which can lead to heart failure. At this stage, patients require a heart transplantation as treatment.

More than 50% of all ACM cases are caused by a mutation in one of the desmosomal genes, which together form complex protein structures known as desmosomes. Desmosomes form "bridges" between individual heart muscle cells, allowing the cells to contract in a coordinated manner. Most of the desmosomal mutations that cause ACM occur in a gene called plakophilin-2.

The researchers used the genetic tool  CRISPR/Cas9 to introduce the human plakophilin-2 mutation in mice to mimic ACM. This allowed them to study progression of the disease in more detail. They observed that old ACM mice carrying this mutation had lower levels of desmosomal proteins and heart relaxation issues, similar to ACM patients.

Strikingly, the researchers discovered that the mutation lowered levels of desmosomal proteins even in young, healthy mice of which the heart contracted normally. From this they concluded that a loss of desmosomal proteins could underlie the onset of ACM caused by a plakophilin-2 mutation.

The researchers then moved on to explain the loss of desmosomal proteins. For this they studied both RNA and protein levels in their ACM mice. "The levels of desmosomal proteins were lower in our ACM mice compared to healthy control mice. However, the RNA levels of these genes were unchanged. They discovered that these surprising findings are the result of increased protein degradation in ACM hearts.

When the researchers treated their ACM mice with a drug that prevents protein degradation, the levels of desmosomal proteins were restored. More importantly, the restored levels of desmosomal proteins improved calcium handling of heart muscle cells, which is vital for their normal function.

The results of this study raise new insights into ACM development and indicate that protein degradation could be an interesting target for future therapies.

 Desmosomal protein degradation as an underlying cause of arrhythmogenic cardiomyopathy. Science Translational Medicine, 2023; 15 (688) DOI: 10.1126/scitranslmed.add4248

How football-shaped molecules occur in the universe

For a long time it has been suspected that fullerene and its derivatives could form naturally in the universe. These are large carbon molecules shaped like a football, salad bowl or nanotube. An international team of researchers using the Swiss SLS synchrotron light source at PSI has shown how this reaction works. The results have just been published in the journal Nature Communications.

The planets and  human beings and all the life forms  are actually made up of dust from burnt-out supernovae and carbon compounds billions of years old. The universe is a giant reactor and understanding these reactions means understanding the origins and development of the universe—and where life - especially humans come from.

In the past, the formation of fullerenes and their derivatives in the universe has been a puzzle. These carbon molecules, in the shape of a football, bowl or small tube, were first created in the laboratory in the 1980s. In 2010 the infrared space telescope Spitzer discovered the C₆₀ molecules with the characteristic shape of a soccer ball, known as buckyballs, in the planetary nebula Tc 1. They are therefore the biggest molecules to have been discovered to date known to exist in the universe beyond our solar system.

But how do they actually form there? A team of researchers has now completed an important reaction step in the formation of the molecules, with active support from PSI and the vacuum ultraviolet (VUV) beamline of the synchrotron light source Swiss SLS.

Scientists working on the VUV beamline at PSI, has built a mini reactor for observing the formation of fullerene in real time. A corannulene radical (C₂₀H₉) is created in a reactor at a temperature of 1,000 degrees Celsius. This molecule looks like a salad bowl, as if it had been dissected from a C₆₀ buckyball. This radical is highly reactive. It reacts with vinyl acetylene (C₄H₄), which deposits a layer of carbon onto the rim of the bowl.

By repeating this process many times, the molecule would grow into the end cap of a nanotube. We have managed to demonstrate this phenomenon in computer simulations.

Part 1

The reaction produces different isomers—molecules that all have the same mass, but slightly different structures. With standard mass spectrometry, all these variants produce the same signal. But the outcome is different when using photoelectron photoion coincidence spectroscopy, the method adopted by the team. With this technique, the structure of the measurement curve allows conclusions to be drawn about each individual isomer.

The universe contains a wild jungle of molecules and chemical reactions—not all of them can be distinctly classified in the signals from telescopes.

Scientists already know from models that both corannulene and vinylacetylene exist in the universe. Now it has been possible to confirm that these molecules actually form the building blocks to fullerene.

 The researchers want to conduct more experiments in order to understand how the classic buckyballs form in the universe, along with the football-shaped fullerene molecules with 60 carbon atoms and the minute nanotubes with even more atoms.

Lotefa B. Tuli et al, Gas phase synthesis of the C₄₀ nano bowl C₄₀H₁₀, Nature Communications (2023). DOI: 10.1038/s41467-023-37058-y

Part 2

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Human body is a breeding ground for antimicrobial resistance genes, shows new study

The community of microbes living in and on our bodies may be acting as a reservoir for antibiotic resistance, according to new research.

The use of antibiotics leads to "collateral damage" to the microbiome, ramping up the number of resistance genes being passed back and forth between strains in the microbiome. The findings also suggest these genes spread so easily through a population, that regardless of your own health and habits, the number of resistance genes in your gut is heavily influenced by national trends in antibiotic consumption.

The rise of antimicrobial resistance (AMR) among human pathogens is widely seen as one of the most serious threats to global health in the coming decades. AMR is already believed to be contributing to tens of thousands of deaths in the world each year.

Tracking the emergence and spread of genes that help these pathogens to shrug off antibiotics has generally been limited to samples taken from infected individuals. The majority of microbes living in the human body, however, are not pathogenic.

The human microbiome is a complex and dynamic community of millions of species of microbes, primarily living in the gut and coexisting with us. Microbiomes play an important role in health and disease, with the gut microbiome known to help with the digestion of food and the development of our immune system.

Even a healthy individual who hasn't taken antibiotics recently is constantly bombarded by microbes from people or even pets they interact with, which leads to resistance genes becoming embedded in their own microbiota. If they exist in a population with a heavy burden of antibiotic consumption, it leads to more resistance genes in their microbiome.

To better understand the impact of antimicrobials on the gut microbiome, researchers analyzed over 3,000 gut microbiome samples, collected from healthy individuals across 14 countries. They then compared the resistance genes identified in samples to those found in large genome collections in order to understand the movement of AMR genes between microbe and pathogen species.

They carefully catalogued and recorded the number of antimicrobial resistance genes found in the samples by comparing data to the Comprehensive Antibiotic Resistance Database, a public health resource where resistance genes are documented.

The team identified a median of 16 AMR genes per stool sample analyzed. They also found that the median number of genes varied across the 14 countries for which they had data. For example, they saw a five-fold variation in median resistance levels between the lowest in the Netherlands and the highest in Spain.

Using World Health Organization and ResistanceMap data, the team were able to show a strong correlation between the frequency of resistance genes present in a country and national antibiotic consumption levels.

Part 1

The researchers found that in countries where antibiotics are taken more regularly, their populations also have higher numbers of resistance genes in their gut microbiome.

The reason this collateral damage is such a major problem is that microbes are constantly sharing genes with each other. Known as horizontal gene transfer, this process helps AMR genes to spread back and forth between species. Our bodies are continually importing and exporting microbes and pathogen strains. These strains are themselves passing genes back and forth, which means the challenge of AMR has to be tackled at both the micro and macro level. Given our complex relationship with microbes, we need to do more research to understand how we maximize the benefits and minimize the risks when it comes to guiding treatment decisions and developing new medicines.

We've known for some years that antimicrobial resistance genes can spread incredibly fast between gut bacteria. This study is so important because it can, for the first time, quantify the impact national antibiotic usage has on our commensal bacteria, as well as giving us insights into the common types of resistance we can expect to evolve.

Kihyun Lee et al, Population-level impacts of antibiotic usage on the human gut microbiome, Nature Communications (2023). DOI: 10.1038/s41467-023-36633-7

Part 2

Methane cools even as it heats

Most climate models do not yet account for a new  discovery: methane traps a great deal of heat in Earth's atmosphere, but also creates cooling clouds that offset 30% of the heat!

Greenhouse gases like methane create a kind of blanket in the atmosphere, trapping heat from Earth's surface, called longwave energy, and preventing it from radiating out into space. This makes the planet hotter.

A blanket doesn't create heat, unless it's electric. You feel warm because the blanket inhibits your body's ability to send its heat into the air. This is the same concept.

In addition to absorbing longwave energy, it turns out methane also absorbs incoming energy from the sun, known as shortwave energy. This should warm the planet. But counterintuitively, the shortwave absorption encourages changes in clouds that have a slight cooling effect.

This effect is detailed in the journal Nature Geoscience, alongside a second finding that the researchers did not fully expect. Though methane generally increases the amount of precipitation, accounting for the absorption of shortwave energy suppresses that increase by 60%.

Both types of energy—longwave (from Earth) and shortwave (from sun)—escape from the atmosphere more than they are absorbed into it. The atmosphere needs compensation for the escaped energy, which it gets from heat created as water vapour condenses into rain, snow, sleet, or hail.

Essentially, precipitation acts as a heat source, making sure the atmosphere maintains a balance of energy.

Part 1

Methane changes this equation. By holding on to energy from the sun, methane is introducing heat the atmosphere no longer needs to get from precipitation.

Additionally, methane shortwave absorption decreases the amount of solar radiation reaching Earth's surface. This in turn reduces the amount of water that evaporates. Generally, precipitation and evaporation are equal, so a decrease in evaporation leads to a decrease in precipitation.

This has implications for understanding in more detail how methane and perhaps other greenhouses gases can impact the climate system. Shortwave absorption softens the overall warming and rain-increasing effects but does not eradicate them at all.

Robert J. Allen et al, Surface warming and wetting due to methane's long-wave radiative effects muted by short-wave absorption, Nature Geoscience (2023). DOI: 10.1038/s41561-023-01144-z

Part 2

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Are Air Fryers Healthy For Us?

Researchers identify specific regions of the brain damaged by high blood pressure, involved in mental decline, dementia

For the first time, researchers have identified specific regions of the brain that are damaged by high blood pressure and may contribute to a decline in mental processes and the development of dementia.

High blood pressure is known to be involved in causing dementia and damage to brain function. The study, which is published in the European Heart Journal recently, shows how this happens. It gathered information from a combination of magnetic resonance imaging (MRI) of brains, genetic analyses and observational data from thousands of patients to look at the effect of high blood pressure on cognitive function.

The researchers then checked their findings in a separate, large group of patients in Italy who had high blood pressure, and found that the parts of the brain the researchers had identified were indeed affected. Further research also found that genes that cause high BP and other factors are not involved in these changes.

The researchers found changes to nine parts of the brain were related to higher blood pressure and worse cognitive function. These included the putamen, which is a round structure in the base of the front of the brain, responsible for regulating movement and influencing various types of learning. Other areas affected were the anterior thalamic radiation, anterior corona radiata and anterior limb of the internal capsule, which are regions of white matter that connect and enable signaling between different parts of the brain. The anterior thalamic radiation is involved in executive functions, such as the planning of simple and complex daily tasks, while the other two regions are involved in decision-making and the management of emotions.

The changes to these areas included decreases in brain volume and the amount of surface area on the brain cortex, changes to connections between different parts of the brain, and changes in measures of brain activity.

Tomasz J Guzik et al, Genetic analyses identify brain structures related to cognitive impairment associated with elevated blood pressure, European Heart Journal (2023). DOI: 10.1093/eurheartj/ehad101

Ernesto L. Schiffrin et al, Hypertension, brain imaging phenotypes and cognitive impairment: lessons from Mendelian randomisation, European Heart Journal (2023). DOI: 10.1093/eurheartj/ehad187

Using bacteria to convert CO2 in the air into a polyester

A team of chemical and biomolecular engineers at Korea Advanced Institute of Science and Technology has developed a scalable way to use bacteria to convert CO2 in the air into a polyester. In their paper, published in Proceedings of the National Academy of Sciences, the group describes their technique and outline its performance when tested over a several-hour period.

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How scientists cut their carbon footprints

As the effects of climate change grow, scientists from fields spanning astronomy to biology are trying to decarbonize their research. They say that the time for carbon-footprint assessments is over — we must take action, and that needs institutional support. “The situation is not that different from the one you can experience as a citizen,” says Pierrick Martin, an astrophysicist at an institute that is trying to reduce the heavy toll of its observatory. “There are things you can do yourself, at your level, in your local environment, that are worth something. But this has limits, and you can’t escape from political decisions at some point.”

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Light-bending gravity reveals one of the biggest black holes ever found

A video showing how Astronomers used gravitational lensing to discover a black hole 30 billion times the mass of the sun in a galaxy 2 billion light years away. 

Severe hepatitis outbreak linked to common childhood viruses

A new  study brings scientists closer to understanding the causes of a mysterious rash of cases of acute severe hepatitis that began appearing in otherwise healthy children after COVID-19 lockdowns eased in several countries in the spring of 2022.

Pediatric hepatitis  is rare, and doctors were alarmed when they started seeing outbreaks of severe unexplained hepatitis. There have been about 1,000 cases to date; 50 of these children needed liver transplants and at least 22 have died.

In the study, published on March 30 in Nature, researchers linked the disease to co-infections from multiple common viruses, in particular a strain of adeno-associated virus type2 (AAV2). AAVs are not known to cause hepatitis on their own. They need "helper" viruses, such as adenoviruses that cause colds and flus, to replicate in the liver.

Once they returned to school, children were more susceptible to infections with these common pathogens. The study suggests that for a small subset of these children, getting more than one infection at the same time may have made them more vulnerable to severe hepatitis.

 The infections researchers detected in these children were caused not by an unusual, emerging virus, but by common childhood viral pathogens. 

Charles Chiu, Adeno-associated virus type 2 in US children with acute severe hepatitis, Nature (2023). DOI: 10.1038/s41586-023-05949-1. www.nature.com/articles/s41586-023-05949-1

Emma Thomson, Adeno-associated virus 2 infection in children with non-A-E hepatitis, Nature (2023). DOI: 10.1038/s41586-023-05948-2. www.nature.com/articles/s41586-023-05948-2

New nanoparticles can perform gene-editing in the lungs

Chemical Engineers have designed a new type of nanoparticle that can be administered to the lungs, where it can deliver messenger RNA encoding useful proteins.

With further development, these particles could offer an inhalable treatment for cystic fibrosis and other diseases of the lung, the researchers say.

This is the first demonstration of highly efficient delivery of RNA to the lungs in mice. Scientists are hopeful that it can be used to treat or repair a range of genetic diseases, including cystic fibrosis.

This is the first demonstration of highly efficient delivery of RNA to the lungs in mice. Researchers are hopeful that it can be used to treat or repair a range of genetic diseases, including cystic fibrosis.

Messenger RNA holds great potential as a therapeutic for treating a variety of diseases caused by faulty genes. One obstacle to its deployment thus far has been difficulty in delivering it to the right part of the body, without off-target effects. Injected nanoparticles often accumulate in the liver, so several clinical trials evaluating potential mRNA treatments for diseases of the liver are now underway. RNA-based COVID-19 vaccines, which are injected directly into muscle tissue, have also proven effective. In many of those cases, mRNA is encapsulated in a lipid nanoparticle—a fatty sphere that protects mRNA from being broken down prematurely and helps it enter target cells.

In their new study, the researchers set out to develop lipid nanoparticles that could target the lungs. The particles are made up of molecules that contain two parts: a positively charged headgroup and a long lipid tail. The positive charge of the headgroup helps the particles to interact with negatively charged mRNA, and it also help mRNA to escape from the cellular structures that engulf the particles once they enter cells.

The lipid tail structure, meanwhile, helps the particles to pass through the cell membrane. The researchers came up with 10 different chemical structures for the lipid tails, along with 72 different headgroups. By screening different combinations of these structures in mice, the researchers were able to identify those that were most likely to reach the lungs.

In further tests in mice, the researchers showed that they could use the particles to deliver mRNA encoding CRISPR/Cas9 components designed to cut out a stop signal that was genetically encoded into the animals' lung cells. When that stop signal is removed, a gene for a fluorescent protein turns on. Measuring this fluorescent signal allows the researchers to determine what percentage of the cells successfully expressed the mRNA.

After one dose of mRNA, about 40 percent of lung epithelial cells were transfected, the researchers found. Two doses brought the level to more than 50 percent, and three doses up to 60 percent. The most important targets for treating lung disease are two types of epithelial cells called club cells and ciliated cells, and each of these was transfected at about 15 percent.

This means that the cells we were able to edit are really the cells of interest for lung disease. This lipid can enable us to deliver mRNA to the lung much more efficiently than any other delivery system that has been reported so far.

Wen Xue, Combinatorial design of nanoparticles for pulmonary mRNA delivery and genome editing, Nature Biotechnology (2023). DOI: 10.1038/s41587-023-01679-x. www.nature.com/articles/s41587-023-01679-x

Part 2

Can a solid be a superfluid? Engineering a novel supersolid state from layered 2D materials

A collaboration of Australian and European physicists predict that layered electronic 2D semiconductors can host a curious quantum phase of matter called the "supersolid."

The supersolid is a very counterintuitive phase indeed. It is made up of particles that simultaneously form a rigid crystal and yet at the same time flow without friction since all the particles belong to the same single quantum state.

A solid becomes "super" when its quantum properties match the well-known quantum properties of superconductors. A supersolid simultaneously has two orders, solid and super:

• Solid because of the spatially repeating pattern of particles.
• Super because the particles can flow without resistance.

Although a supersolid is rigid, it can flow like a liquid without resistance.

The new Australia-Europe study predicts that a state could  be engineered in two-dimensional (2D) electronic materials in a semiconductor structure, fabricated with two conducting layers separated by an insulating barrier of thickness d.

One layer is doped with negatively-charged electrons and the other with positively-charged holes. The particles forming the supersolid are interlayer excitons, bound states of an electron and hole tied together by their strong electrical attraction. The insulating barrier prevents fast self-annihilation of the exciton bound pairs. Voltages applied to top and bottom metal "gates" tune the average separation r0 between excitons. The research team predicts that excitons in this structure will form a supersolid over a wide range of layer separations and average separations between the excitons. The electrical repulsion between the excitons can constrain them into a fixed crystalline lattice. "A key novelty is that a supersolid phase with Bose-Einstein quantum coherence appears at layer separations much smaller than the separation predicted for the non-super exciton solid that is driven by the same electrical repulsion between excitons.

In this way, the supersolid pre-empts the non-super exciton solid. At still larger separations, the non-super exciton solid eventually wins, and the quantum coherence collapses.

This is an extremely robust state, readily achievable in experimental setups.

Sara Conti et al, Chester Supersolid of Spatially Indirect Excitons in Double-Layer Semiconductor Heterostructures, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.130.057001

Water is getting scarce. And experts are advising to conserve it ane reduce your water footprint. 

Steps to reduce your water footprint

Meriano offers the following tips for saving water inside and outside the home:

• Fix leakages or dripping immediately from toilets, hot water heaters or other pipes and make sure to turn taps off all the way.
• Showers use less water than baths but if you need to take a soak, don't fill the tub all the way.
• When opportunity arises, choose a new washing machine, toilet, showerhead or dishwasher that uses less water.
• Rainwater that flows down gutters can be collected and used to water plants and gardens.
• Water lawns when it's not hot so water doesn't evaporate, and don't water them on windy days.
• Keeping blades of grass longer can also shelter the roots and cause lawns to need less water.

All health is reliant and dependent on clean water. "You can't have healthy populations without having access to clean water."

Moths are more efficient pollinators than bees, shows new research

Moths are more efficient pollinators at night than day-flying pollinators such as bees, finds new research, published March 29 in PLOS ONE.

Amid widespread concern about the decline of wild pollinating insects like bees and butterflies,  researchers have discovered that moths are particularly vital pollinators for nature.  They found that 83% of insect visits to bramble flowers were made during the day. While the moths made fewer visits during the shorter summer nights, notching up only 15% of the visits, they were able to pollinate the flowers more quickly.

As a result, the researchers concluded that moths are more efficient pollinators than day-flying insects such as bees, which are traditionally thought of as "hard-working." While day-flying insects have more time available to transfer pollen, moths were making an important contribution during the short hours of darkness.

This research shows that both night-flying and day-flying pollinators need to be protected in order to allow natural ecosystems to flourish.

 Max Anderson et al, Marvellous moths! pollen deposition rate of bramble (Rubus futicosus L. agg.) is greater at night than day, PLOS ONE (2023). DOI: 10.1371/journal.pone.0281810

 Poisonous Birds: Researchers discover birds with neurotoxin-laden feathers in New Guinea

An expedition into the jungle of New Guinea has resulted in the discovery of two new species of poisonous birds by researchers. The poisonous birds inhabit one of Earth's most pristine rainforests, a place as exotic as no other in the world. Hearing the words poisonous and bird coupled will be an eye-opener for most. But poisonous birds actually exist. And now, more species have been discovered in New Guinea's jungles. These birds contain a neurotoxin that they can both tolerate and store in their feathers.

These birds contain a neurotoxin that they can both tolerate and store in their feathers

Part 1

The two birds that the researchers discovered to be poisonous are the regent whistler (Pachycephala schlegelii), a species that belongs to a family of birds with a wide distribution and easily recognizable song well-known from across the Indo-Pacific region, and the rufous-naped bellbird (Aleadryas rufinucha).

Most people are familiar with South and Central America's iconic poison dart frogs—especially the golden poison frog. These small, brightly colored amphibians can kill a human at the slightest touch. The discovery of the two new poisonous bird species in New Guinea, which carry the same type of toxin in their skin and feathers, demonstrates that the frog toxin is more widespread than once believed.

The poison in these birds' bodies and plumage is called Batrachotoxin. It is an incredibly potent neurotoxin that, in higher concentrations, such as those found in the skin of golden poison frogs, leads to muscle cramps and cardiac arrest nearly immediately after contact.

The bird's toxin is the same type as that found in frogs, which is a neurotoxin that, by forcing sodium channels in skeletal muscle tissue to remain open, can cause violent convulsions and ultimately death.

Though the level of toxicity of the New Guinean birds is less lethal, it may still serve a defensive purpose, but the adaptive significance for the birds is yet uncertain.

The locals aren't fond of spicy food and steer clear of these birds, because, according to them, their meat burns in the mouth like chili. In fact that's how researchers first became aware of them. And the toxin can be felt when holding onto one of them. It feels kind of unpleasant, and hanging on to one for long isn't an appealing option. This could indicate that the poison serves them as a deterrence of those who would want to eat them to some degree.

According to the researchers, the poisonous birds are an expression of an everlasting evolutionary arms race in nature. It starts at the bottom of the food chain with beetles, insects and other invertebrates. Over time, some of these develop toxicity to avoid being eaten. Perhaps they also acquire a particular coloration that may serve as a warning. This in turn allow them to venture from their hideouts beneath logs and rocks.

Part 2

There is a distinction in biology between the two ways that animals deploy poisons. There are poisonous animals that produce toxins in their bodies and others that absorb toxins from their surroundings. Like the frogs, the birds belong to the latter category. Both are believed to acquire toxins from what they eat. Beetles containing the toxin have been found in the stomachs of some of the birds. But the source of the toxin itself has yet to be determined.

What makes it possible for these birds to have a toxin in their bodies without themselves being harmed? The researchers studied this with inspiration from poison dart frogs, whose genetic mutations prevent the toxin from keeping their sodium channels open, and thereby preventing cramps.

So, it was natural to investigate whether the birds had mutations in the same genes. Interestingly enough, the answer is yes and no. The birds have mutations in the area that regulates sodium channels, and which we expect gives them this ability to tolerate the toxin, but not in the exact same places as the frogs.

Finding these mutations that can reduce the binding affinity of Batrathotoxin in poisonous birds in similar places as in poison dart frogs, is quite cool. And it showed that in order to adapt to this Batrachotoxin lifestyle, you need some sort of adaptation in these sodium channels".

Therefore, these studies of the birds establish that while their neurotoxin is similar to that of the South American poison dart frogs, the birds developed their resistance and ability to carry it in the bodies independently of the frogs. This is an example of what biologists refer to as convergent evolution.

 Kasun H. Bodawatta et al, Multiple mutations in the Nav1.4 sodium channel of New Guinean toxic birds provide autoresistance to deadly batrachotoxin, Molecular Ecology (2023). DOI: 10.1111/mec.16878

Part 3

Scientists observe flattest explosion ever seen in space

An explosion the size of our solar system has baffled scientists, as part of its shape—similar to that of an extremely flat disk—challenges everything we know about explosions in space.

The explosion observed was a bright Fast Blue Optical Transient (FBOT)—an extremely rare class of explosion which is much less common than other explosions, such as supernovas. The first bright FBOT was discovered in 2018 and given the nickname "the cow."

Explosions of stars in the universe are almost always spherical in shape, as the stars themselves are spherical. However, this explosion, which occurred 180 million light years away, is the most aspherical ever seen in space, with a shape like a disk emerging a few days after it was discovered. This section of the explosion may have come from material shed by the star just before it exploded.

It's still unclear how bright FBOT explosions occur, but it's hoped that this observation, published in Monthly Notices of the Royal Astronomical Society, will bring us closer to understanding them.

Justyn R Maund et al, A flash of polarized optical light points to an aspherical 'cow', Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad539

Ban On Tattoo Ink: Breaking Down the Chemistry

Microplastic found in Antarctic krill and salps

A new study by researchers discovered microplastics in krill (Euphausia superba), a small shrimp-like crustacean, and salps (Salpa thompsoni), a gelatinous marine invertebrate. The results were published in the journal Royal Society Open Science.

While Antarctic krill have been observed ingesting microplastics in laboratory settings, the team's findings provide important evidence that these animals, as well as other zooplankton, ingest plastic in their natural environment.

Microplastics are present in the Southern Ocean from the sea surface to seabed. Due to the small size of these particles (<5 mm), Antarctic zooplankton are likely to mistake the plastics for their natural food source. The team focused on two of the most abundant species of Southern Ocean zooplankton: Antarctic krill, and salps. These two species are critical to the diet of much of the Southern Ocean's marine wildlife. Krill is the main food source for whales, penguins, and seals while salps are eaten by some fish and larger marine birds.

Krill and salp samples were collected onboard the research ship RRS James Clark Ross on two research missions off the Northern tip of the Antarctic Peninsula in 2016 and near the island of South Georgia in 2018. Microplastics were extracted from both species with plastic microfibers most common. One of the largest sources of these fibers is shedding from clothing during washing and drying. Around 60% of the krill and salps contained nylon, a microplastic with significant commercial applications in clothing, fishing gear, ropes, and reinforcing car tires.

The findings underline how sensitive the Antarctic marine ecosystem is to plastic pollution. Due to the short food chains in the Antarctic, transfer of these microplastics from the krill to larger predators such as whales, penguins, and seals is highly likely. Plastic in krill and salps could also negatively impact the Southern Ocean as one of the planets largest carbon sinks.

Scientists have found microplastic pollution in krill and salps from the Southern Ocean. A new study led by researchers at British Antarctic Survey shares important evidence that these animals, as well as other zooplankton, ingest plastic in their natural environment. Krill and salps are vital food sources to much of the Southern Ocean’s wildlife as well as helping to trap carbon from the atmosphere in the deep ocean. The impact of the microplastics in this environment is not fully understood and could interfere with their ability to trap carbon as well as getting transferred up the food chain to animals such as whales and penguins. The team found plastics in most krill and salp samples with the most common type being nylon, a fibre with wider ranging applications from clothing to car tires. ➡ Read this news story on the British Antarctic Survey website: https://www.bas.ac.uk/media-post/micr...

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Gigapixel 3D Microscope Captures Life in Unprecedented Detail

A new kind of microscope that stitches together videos from dozens of smaller cameras can provide researchers with 3D views of their experiments. Whether recording 3D movies of the behavior of dozens of freely swimming zebrafish or the grooming activity of fruit flies at near cellular-level detail across a very wide field of view, the device is opening new possibilities to researchers the world over. Learn more at https://www.pratt.duke.edu/about/news...

Neck cracking

It is thought that one of the most common causes of neck ‘cracking’ is gas bubbles in the synovial fluid escaping a tight space. This synovial fluid

is a lubricant between the joints, formed by a combination of carbon dioxide, nitrogen and oxygen.

If you deliberately roll your neck, it is thought that you can sometimes release these bubbles, resulting in a series of popping sounds that may sound like cracking. The release of the gas build-up explains why muscles or joints often feel looser and more comfortable after they’ve been ‘popped’ or ‘cracked’.

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Our joints contain synovial fluid, a sac of liquid which acts as a lubricant, protecting bones from grinding against each other. When someone cracks their knuckles, they increase the space in the joint, causing bubbles of gas (think oxygen, nitrogen and carbon dioxide) to form in the fluid. It’s the popping of these bubbles that make the cracking noise.

While it may sound worrying, there isn’t actually much evidence to suggest this is dangerous – or increases the risk of getting arthritis. The most important risk factors for developing arthritis are family history, age, gender, joint injury, and lifestyle elements such as smoking and obesity.

It is true that people with arthritis sometimes find their joints crack, but this is because their cartilage has already been damaged. Cracking isn’t usually the most common symptom of arthritis, either.

Although there are isolated reports of self-injury caused from cracking knuckles, such as sprained ligaments, these are very rare. You’re much more likely to harm yourself by cracking joints in your spine and neck, which are surrounded by important blood vessels.

Crystallised intelligence (the ability to accumulate knowledge, facts and skills) 

Fluid intelligence (the ability to reason and think flexibly)

Photosynthetic Sea Slugs 

Obesity treatment could offer dramatic weight loss without surgery ...

Imagine getting the benefits of gastric bypass surgery without going under the knife—a new class of compounds could do just that. In lab animals, these potential treatments reduce weight dramatically and lower blood glucose. The injectable compounds also avoid the side effects of nausea and vomiting that are common with current weight-loss and diabetes drugs. Now, scientists report that the new treatment not only reduces eating but also boosts calorie burn.

ACS Spring 2023: Peptide triagonists of the GLP-1-, neuropeptide Y1- and neuropeptide Y2- receptors for glycemic control and weight loss, www.acs.org/meetings/acs-meetings/spring-2023.html

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Time-restricted eating vs. daily calorie restriction in reducing no...

Adults with obesity and nonalcoholic fatty liver disease did not see additional reductions in intrahepatic triglyceride while on a time-restricted eating regimen compared to subjects on a daily calorie-restriction diet. This is according to a recent study published in the journal JAMA Network Open and led by researchers at Southern Medical University in Guangzhou, China and colleagues in the US at Tulane University School of Public Health and Tropical Medicine in New Orleans.

Xueyun Wei et al, Effects of Time-Restricted Eating on Nonalcoholic Fatty Liver Disease, JAMA Network Open (2023). DOI: 10.1001/jamanetworkopen.2023.3513

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Study finds harmful PFAS don't actually prevent furniture stains

The health and environmental harms of per- and polyfluoroalkyl substances (PFAS) are well-known, but a new study calls into question their touted stain-fighting benefits. The study, published today in the AATCC Journal of Research, tested the performance of PFAS finishings on furniture fabrics and found that they had limited to no effectiveness, particularly under real-world conditions.

From yeast to mice, from mice to man: Senescent cells get noisier with age

Getting old seems completely avoidable in youth but becomes less and less so as we age. Many of the obstacles of advanced aging are well understood, including declining eyesight, hearing loss, back, neck and arthritic joint pains, shortness of breath, diabetes, Alzheimer's disease, dementia, cancer and stroke, just to name a few. What is less understood are the cellular-level molecular mechanisms responsible for our overall decline.

So researchers pursued an investigation into the chromatin-mediated loss of transcriptional fidelity during human cellular senescence. Their findings are described in an article titled "Spurious intragenic transcription is a feature of mammalian cellular senescence and tissue aging," published in the journal Nature Aging. 

Senescence is the step cells take when they determine it is best not to replicate, inhibiting the proliferation of abnormal cells by altering chromosomal configurations. Essentially as we age, our dividing cells accumulate mutations, little changes from one generation of cells to the next. Enough of these and the cell is at risk of being unsustainable or becoming a tumor cell. In this sense, senescence plays an essential role in limiting tumor progression.

Senescence is also a response to damage, allowing for the suppression of damaged or poorly repaired cells or damage of the telomeres. Accelerated accumulation of senescent cells with age is associated with various forms of disease—osteoarthritis, lung disease, Alzheimer's, dementia and cancer, to name a few.

Scientists found that during aging and senescence, cryptic transcription (proteins not normally produced) are suddenly created inside cells and that this is related to changes in the chromatin landscape. The study proposes that cryptic transcription is spurious and not created for a specific purpose. The noisy cryptic transcriptome then competes indirectly with coherent transcriptional networks by expending cells' energy on their production. Researchers saw no evidence of cryptic transcription being sensed as damage by the cell, nor do they think it is causative of senescence but simply a result of changes brought on by senescence.

The study, along with an experiment in mouse livers, builds on previous observations of cryptic transcription and indicates that this senescence  mechanism is conserved from yeast to mice and humans. The study also finds, similar to previous reports, that cryptic transcription tissue location is sex-dependent, as males and females will manifest spurious proteins in different cell types.

Payel Sen, Spurious intragenic transcription is a feature of mammalian cellular senescence and tissue aging, Nature Aging (2023). DOI: 10.1038/s43587-023-00384-3. www.nature.com/articles/s43587-023-00384-3

Isima, N., Gil, J. Spurious transcription may be a hallmark of aging. Nature Aging (2023). DOI: 10.1038/s43587-023-00398-x. www.nature.com/articles/s43587-023-00398-x

Serotonin gates the transfer of visual information from the eyes to the thalamus

Humans are known to perceive the environment around them differently based on the situation they are in and their own feelings and sensations. Internal states, such as fear, arousal or hunger can thus affect the ways in which sensory information is processed and registered by the brain.

Researchers have recently carried out a study investigating the possible effects of serotonin, a neurotransmitter known to regulate sleep, mood, sexual desire, and other inner states, in the processing of visual information. Their findings, published in Neuron, suggest that serotonergic neurons in the brainstem (i.e., the central trunk of the mammalian brain) gate the transfer of visual information from the eyes to the thalamus, an egg-shaped area of the brain.

Internal states are known to affect sensory perception and processing, but this was generally thought to occur in the cortex or thalamus. 

Previous studies revealed that arousal can suppress certain visual information channels at an earlier stage of the visual pathway––at the connection between the mouse retina and the thalamus, before the information even reaches the brain. This form of 'filtering' of information suggests a very efficient means of processing only relevant information. 

Past studies have also found that internal states, including arousal, are mediated by neuromodulatory systems in the brainstem and other areas below the cortex, including the serotonergic system. This is essentially the system responsible for regulating physiological states through the transmission of serotonin.

Researchers specifically explored now the effects of serotonin on the early processing of visual information and its transfer from the eyes to the thalamus. To do this, they used a technique known as two-photon calcium imaging to track the activity of individual retinal axons in the brains of awake mice as they viewed visual images on a computer monitor.

While examining the mice, the researchers also increased the release of serotonin in the thalamus, by optogenetically stimulating serotonergic neurons as they entered the thalamus. Optogenetic stimulation is a research technique used to intensify the activity of a set of genetically defined neurons using light.

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The experiments carried out by this team of researchers yielded very interesting results. Notably, they showed that serotonin can suppress calcium signals in retinal axons and the release of glutamate in the thalamus. This ultimately reduces the transmission of visual signals from the eye to the thalamus.

When they analyzed their results more in detail, the researchers  found that some classes of retinal axons tended to be more suppressed by serotonin, with classes that responded to broad changes in light levels being more affected than those responding to fine visual details.

The researchers also compared the selective modulation observed in their experiments to that naturally occurring when animals or humans are highly aroused. They found that periods of high arousals that were not accompanied by an increase in the release of serotonin tended to suppress the retinal axons transmitting information about fine details, rather than changes in light levels.

Overall, the results of this study confirm that different internal states can impact the processing of separate types of visual information. 

Jasmine D.S. Reggiani et al, Brainstem serotonin neurons selectively gate retinal information flow to thalamus, Neuron (2022). DOI: 10.1016/j.neuron.2022.12.006

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New shape-shifting antibiotics could fight deadly infections

Antibiotics are essential and effective, but in recent years overuse has led to some bacteria developing resistance to them. The infections are so difficult to treat, the World Health Organization deemed antibiotic resistance a top 10 global public health threat.

Researchers have now  created a new weapon against these drug-resistant superbugs—an antibiotic that can shape-shift by rearranging its atoms.

They came up with the idea of shape-shifting antibiotics while observing tanks in military training exercises. With rotating turrets and nimble movements, the tanks could respond quickly to possible threats.

A few years later, the researchers learned of a molecule called bullvalene. Bullvalene is a fluxional molecule, meaning its atoms can swap positions. This gives it a changing shape with over a million possible configurations—exactly the fluidity they were  looking for.

Several bacteria, including MRSA, VRSA, and VRE, have developed resistance to a potent antibiotic called vancomycin, used to treat everything from skin infections to meningitis. Moses thought he could improve the drug's bacteria-fighting performance by combining it with bullvalene.

Then they turned to click chemistry, a Nobel Prize–winning class of fast, high-yielding chemical reactions that "click" molecules together reliably. This makes the reactions more efficient for wide-scale use.

Using this technique, teh researchers created a new antibiotic with two vancomycin "warheads" and a fluctuating bullvalene center.

They tested the new drug in collaboration with Dr. Tatiana Soares da-Costa (University of Adelaide). The researchers gave the drug to VRE-infected wax moth larvae, which are commonly used to test antibiotics. They found the shape-shifting antibiotic significantly more effective than vancomycin at clearing the deadly infection. Additionally, the bacteria didn't develop resistance to the new antibiotic.

Researchers can use click chemistry with shape-shifting antibiotics to create a multitude of new drugs to use against various microbes.

Alessandra Ottonello et al, Shapeshifting bullvalene-linked vancomycin dimers as effective antibiotics against multidrug-resistant gram-positive bacteria, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2208737120

When you’re having a cast removed, why doesn’t the machine cut your limb?

An orthopaedic cast is usually removed with a special cast saw, which is an oscillating power tool. While it might look like it could cause a lot of damage, a cast saw is designed with a sharp, small-toothed blade that rapidly oscillates back and forth over a very small angle to cut material.

This is quite different to a normal circular saw, which has a rotating blade. A cast saw needs resistance to cut, and is specially designed to slice through rigid materials such as plaster. If it comes into contact with soft tissues such as skin, there is less resistance and so the saw will not cause injury.

The unexpected contribution of medieval monks to volcanology

By observing the night sky, medieval monks unwittingly recorded some of history's largest volcanic eruptions. An international team of researchers drew on readings of 12th and 13th century European and Middle Eastern chronicles, along with ice core and tree ring data, to accurately date some of the biggest volcanic eruptions the world has ever seen.

Their results, reported in the journal Nature, uncover new information about one of the most volcanically active periods in Earth's history, which some think helped to trigger the Little Ice Age, a long interval of cooling that saw the advance of European glaciers.

It took the researchers almost five years to examine hundreds of annals and chronicles from across Europe and the Middle East, in search of references to total lunar eclipses and their coloration. Total lunar eclipses occur when the moon passes into the Earth's shadow. Typically, the moon remains visible as a reddish orb because it is still bathed in sunlight bent round the Earth by its atmosphere. But after a very large volcanic eruption, there can be so much dust in the stratosphere—the middle part of the atmosphere starting roughly where commercial aircraft fly—that the eclipsed moon almost disappears.

Medieval chroniclers recorded and described all kinds of historical events, including the deeds of kings and popes, important battles, and natural disasters and famines. Just as noteworthy were the celestial phenomena that might foretell such calamities. Mindful of the Book of Revelation, a vision of the end times that speaks of a blood-red moon, the monks were especially careful to take note of the moon's coloration. Of the 64 total lunar eclipses that occurred in Europe between 1100 and 1300, the chroniclers had faithfully documented 51. In five of these cases, they also reported that the moon was exceptionally dark.

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The researchers realized that the darkest lunar eclipses all occurred within a year or so of major volcanic eruptions. Since they know the exact days of the eclipses, it opened the possibility of using the sightings to narrow down when the eruptions must have happened.

The researchers found that scribes in Japan took equal note of lunar eclipses. One of the best known, Fujiwara no Teika, wrote of an unprecedented dark eclipse observed on 2 December 1229: "The old folk had never seen it like this time, with the location of the disk of the Moon not visible, just as if it had disappeared during the eclipse... It was truly something to fear." The stratospheric dust from large volcanic eruptions was not only responsible for the vanishing moon. It also cooled summer temperatures by limiting the sunlight reaching the Earth's surface. This in turn could bring ruin to agricultural crops.

Strong tropical eruptions can induce global cooling on the order of roughly 1°C over a few years. They can also lead to rainfall anomalies with droughts in one place and floods in another.

Despite these effects, people at the time could not have imagined that the poor harvests or the unusual lunar eclipses had anything to do with volcanoes—the eruptions themselves were all but one undocumented. Scientists only knew about these eruptions because they left traces in the ice of Antarctica and Greenland. By putting together the information from ice cores and the descriptions from medieval texts they can now make better estimates of when and where some of the biggest eruptions of this period occurred.

The collective effect of the medieval eruptions on Earth's climate may have led to the Little Ice Age, when winter ice fairs were held on the frozen rivers of Europe.

Sébastien Guillet, Lunar eclipses illuminate timing and climate impact of medieval volcanism, Nature (2023). DOI: 10.1038/s41586-023-05751-z. www.nature.com/articles/s41586-023-05751-z

Part 2

Previously unknown isotope of uranium discovered

A team of nuclear physicists affiliated with multiple institutions in Japan, working with a colleague from Korea, has discovered a previously unknown uranium isotope with atomic number 92 and mass 241. In their study, reported in the journal Physical Review Letters, the group forced the isotope to reveal itself and tested the results of their efforts to show that what they had found was indeed uranium-241.

T. Niwase et al, Discovery of New Isotope U241 and Systematic High-Precision Atomic Mass Measurements of Neutron-Rich Pa-Pu Nuclei Produced via Multinucleon Transfer Reactions, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.130.132502

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Study shows soil pollution in urban green spaces and natural areas ...

An international study shows that soil in urban green spaces and natural areas share similar levels of multiple contaminants such as metals, pesticides, microplastics and antibiotic resistance genes around the world. Soil contamination is one of the main threats to the health and sustainability of ecosystems.

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Scientists invent spray cooling to lower carbon footprint of data c...

Scientists from Nanyang Technological University, Singapore (NTU Singapore) have invented a more sustainable and green method for cooling down servers in data centers, potentially reducing up to 26% in both energy costs and carbon footprint.

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Euchromatin is not really open in living cells, shows study

DNA and associated proteins in active regions of the genome are condensed but behave like a viscous liquid at the molecular level. This finding greatly increases our understanding of the physical nature of expressed genome 

How were amino acids, one of the key building blocks of life, formed before the origin of life on Earth?

Our solar system formed from a molecular cloud, which was composed of gas and dust that was emitted into the interstellar medium (ISM), a vast space between stars. On collapse of the molecular cloud, the early sun was formed, with a large disk of gas and dust orbiting it. The dusty material collided to produce rocky material that would eventually grow in size to become large bodies called planetesimals.

The planetesimals that formed far enough from the sun, also contained large quantities of ice. The ice consisted of water and other volatile compounds, such as carbon monoxide (CO), carbon dioxide (CO2), methanol (CH3OH) and ammonia (NH3), as well as many other organic compounds, likely including some amino acids. Eventually, the ice melted due to the presence of radioactive material that heated up the bodies. This period of liquid water (termed aqueous alteration) enabled many reactions to occur, including Strecker synthesis and Formose-like reactions, the result being the production of new organic material, including amino acids.

The same process also changed the rocky materials from their original minerals to new secondary minerals, such as phyllosilicates, carbonates, Fe-oxides and Fe-sulfides.

After several millions of years, the planetesimals began to freeze, as the radioactive material was used up. Later catastrophic collisions and interaction with the solar systems planets broke up the large bodies and sent their asteroidal and cometary fragments close to Earth.

Further impact events have since delivered fragments of these asteroids and comets to the Earth's surface, supplying the Earth with large quantities of organic material, including amino acids, over the course of its history.

Part 1

Amino acids are within all living things on Earth, being the building blocks of proteins. Proteins are essential for many processes within living organisms, including catalyzing reactions (enzymes), replicating genetic material (ribosomes), transporting molecules (transport proteins) and providing a structure to cells and organisms (e.g. collagen).

Therefore, amino acids would have been needed in significant amounts within the region where life began on Earth.

Previous work has identified a number of possible settings both on the Early Earth and in extraterrestrial environments that can form amino acids. Interestingly, most amino acids come in at least two forms, whose structures represent mirror images of each other, similar to human hands. Accordingly, these are often referred to as the right-handed or left-handed optical isomers. One interesting characteristic of life on Earth is that it uses one particular type of amino acids in its proteins, the left-handed optical isomer.

Currently, only a certain class of meteorites (carbonaceous chondrites) are known to contain excesses of left-handed optical isomers, which has led to the idea that the amino acids used by life may have originated from these meteorites. Despite this, the amino acids in meteorites could have formed before their incorporation into the meteorites or after the meteorites had already formed.

In a study now published in Nature Communications, a team of scientists analyzed several fragments of the asteroid Ryugu and calculated the abundance of amino acids within them. The abundance of the mineral phases within the particles had been previously reported in another publication, which allowed for a comparison between the abundance of amino acids and minerals. It was found that one particle (A0022) contained a high abundance of an amino  acid that is uncommon in extraterrestrial materials, called dimethylglycine (DMG), whereas the other particle (C0008) did not contain this amino acid above detection limit.

Part 2

Meanwhile, the abundance of the amino acid glycine was found to be lower in A0022 compared to C0008, while the abundance of β-Alanine showed the opposite trend. Accordingly, the ratio of β-Alanine to glycine was higher for A0022 than for C0008. This ratio was shown previously to be indicative of the extent of aqueous alteration operating on planetesimals. Accordingly, it was hypothesized that some reaction related to higher levels of aqueous alteration in A0022 may explain the high abundance of DMG in this particle, compared to C0008.

As such, the mineral phases were examined to see if any additional evidence for what reaction may be causing the different amino acids abundances between the Ryugu particles. It was found that the abundance of secondary minerals (formed after aqueous alteration), including carbonate, magnetite and Fe-sulfides, was higher in A0022 than in C0008.

In particular, the high abundance of carbonate pointed towards a larger quantity of CO or CO₂ within the region of the planetesimal where A0022 had been altered, compared to C0008. In conjunction with the evidence for more intense aqueous alteration from the β-Alanine to glycine ratio, this indicated that more ice in general may have been present in the precursor of A0022 than in C0008.

One way to commercially produce DMG, an important nutrient for humans, is the through the Eschweiler–Clarke reaction. This reaction requires the interaction of glycine with formic acid and formaldehyde in water and also produces CO₂. Glycine, formaldehyde and formic acid are all found in comets and so it is expected that they would be present in the planetesimal precursors of asteroids.

Therefore, if the Eschweiler–Clarke reaction occurred during aqueous alteration within the precursor of A0022, then it could explain the high level of DMG and lower abundance of glycine in this particle, compared to C0008. Additionally, the CO₂ produced could have further contributed to the formation of carbonates in A0022.

Overall, the findings of the study indicate that slight differences in the conditions present during aqueous alteration on planetesimals can have big effects on the end abundances of amino acids. Some amino acids can be destroyed and others created and this in turn will affect the availability of amino acids at the origin of life on Earth.

Christian Potiszil et al, Insights into the formation and evolution of extraterrestrial amino acids from the asteroid Ryugu, Nature Communications (2023). DOI: 10.1038/s41467-023-37107-6

Part 3

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Study finds evidence of no common blood microbes in healthy humans

There is no stable microbial community residing in the bloodstream of healthy humans, according to a new study.

The new Nature Microbiology paper makes an important confirmation as blood donations are a crucial part of medical practice. Understanding what types of microbes may be found in blood may allow the development of better microbial tests in blood donations, which would minimize the risk of transfusion-related infections.

Human blood is generally considered sterile. While sometimes microorganisms will enter the bloodstream such as via a wound or after tooth-brushing, mostly this is quickly resolved by the immune system.

But in recent decades this paradigm has been challenged by speculation that the blood could host a community of microbes. This new study has confirmed this is not the case, as most people's blood does not contain microbes, and the microbial species found in some people's blood varied substantially between individuals.

In these investigations, after accounting for contamination that is rife in microbiome investigations, the team found that microbes were only rarely and sporadically detected in blood, instead of existing as stable communities. Among their sample of 9,770 people, 84% of people did not have any microbes in their blood sample, and less than 5% of people shared the same species.

The scientists also found evidence that some bacteria in the blood of healthy individuals might be replicating and most of these bacteria are typically found in the human gut, oral, or skin microbiomes. Their findings suggest that microbes do occasionally enter the bloodstream from other body sites without causing disease, but there is no core set of species colonizing the blood of healthy individuals.

The findings also provide a useful resource for the types of microbes that one might expect to occasionally see in the blood of healthy humans. Characterizing the range of microbial species present in the blood of healthy individuals forms a crucial baseline for comparison with that of diseased individuals, shedding light on how blood microbial profiles may correlate with health status.

Cedric C. S. Tan et al, No evidence for a common blood microbiome based on a population study of 9,770 healthy humans, Nature Microbiology (2023). DOI: 10.1038/s41564-023-01350-w

No microbial community in the blood of healthy individuals, Nature Microbiology (2023). DOI: 10.1038/s41564-023-01364-4

Scientists Find Antibiotic-Free Way to Treat Drug-Resistant Infections

Scientists have found an antibiotic-free way of treating 'golden staph' skin infections that are the scourge of some cancer patients, and a threat to hospital-goers everywhere.

The lab study from researchers  utilized an artificial version of an enzyme that's naturally produced by bacteriophages (viruses that infect bacteria), and used it to eradicate Staphylococcus aureus, or golden staph, in biopsy samples from people with skin lymphoma.

To people who are severely ill with skin lymphoma, staphylococci can be a huge, sometimes insoluble problem, as many are infected with a type of Staphylococcus aureus that is resistant to antibiotics. 

S. aureus is a common inhabitant of our skin and nasal tract, and generally harmless. But it is an opportunistic pathogen: When immunity is lowered, it can cause all manner of infections, from minor skin infections such as boils and abscesses, right through to life-threatening illnesses such as pneumonia and sepsis.

In a hospital setting, drug-resistant strains of the bacteria are a grave and growing problem. S. aureus can find its way into the bloodstream during surgery or via medical devices such as catheters, slipping past the body's first line of defense: the skin and mucosal barriers (snot).

People with weakened immune systems who visit hospitals for regular treatments such as chemotherapy are also at risk of picking up nasty 'superbugs' that have become resistant to mainstay antibiotics.

In particular, people with skin lymphoma are highly susceptible to bacterial infections. Called cutaneous T-cell lymphoma, CTCL is a rare form of non-Hodgkin lymphoma that starts with cancerous T cells migrating to the skin. There, these rogue immune cells cause rashes and lesions before spreading to other parts of the body.

S. aureus expels substances called enterotoxins which are thought to fuel the progression of CTCL, because when patients with CTCL finish a round of antibiotics, S. aureus can quickly appear in skin lesions and their cancer symptoms can worsen.

Part 1

Strains of S. aureus that are resistant to methicillin and other antibiotics are called MRSA, and while hospitals are making some ground in curbing MRSA infections, other drug-resistant superbugs are quick to take its place.

So, in this study, researchers experimented with the new class of antibacterial agent called endolysins.

Endolysins are enzymes that are naturally produced by bacteriophages, viruses that infect bacteria. After infection, they slice up molecules called peptidoglycans that form mesh-like scaffolds in the bacteria cell wall, destroying the bacteria from the inside.

Each bacterial species has unique peptidoglycans, which the right endolysin could selectively target. One endolysin, XZ.700, was tested in this study, on skin samples collected from people with healthy skin, and those with CTCL.

The great thing about this enzyme is that it has been designed to penetrate the wall of Staphylococcus aureus. This enables it to target and kill the harmful staphylococcus and leave harmless skin bacteria unharmed.

In lab experiments, endolysin XZ.700 killed off strains of S. aureus that had been isolated from CTCL patients, and blocked its tumor-promoting effects on lab-grown malignant T cells.

Endolysin treatment also "profoundly" stopped S. aureus from colonizing samples of healthy skin and biopsies of lesioned skin from people with CTCL. It also sloughed off S. aureus colonies that had already settled on biopsied skin.

 Lab tests have showed that endolysins do not just eradicate Staphylococcus aureus" from skin samples,  but that they "also inhibit their ability to promote cancer growth."

https://www.jidonline.org/article/S0022-202X(23)00175-6/fulltext