In a new study, astrophysicist Kyu-Hyun Chae of Sejong University in Korea has analyzed nearly 2,500 wide binary star systems observed by European Space Agency's Gaia space telescope, arriving at the conclusion that standard gravity is breaking down at certain points within them.

But binary stars separated by more than 2,000 astronomical units appeared to get a velocity 'boost' at low accelerations, inconsistent with what classical mechanics predicts and regardless of whether hypothetical dark matter was included in the models.

"This gravitational anomaly implies a low-acceleration breakdown of both Newtonian dynamics and general relativity and so has immense implications for astrophysics, cosmology, and fundamental physics," Chae writes in his new paper.

"Thus, one cannot overemphasize the importance of confirming the claimed anomaly from as many independent studies as possible."

While two studies from the same researcher are light-years away from the independent verification theory-overturning results demand, Chae thinks his methods are solid. Although he does admit that theoretical interpretations of the reported anomaly are "wide open."

However, he also makes some big claims in his paper such as "the dark matter paradigm seems now doomed to be abandoned" and that "standard cosmology based on general relativity seems no longer valid, even in principle."

Those types of claims need ridiculously strong evidence to back them up, replicated multiple times over. Chae's paper will no doubt be scrutinized closely by his peers. Nonetheless, it's in findings like this that we might find a way to bridge our gaps in knowledge over gravity's remaining mysteries.

"The evidence for the gravity boost in the low-acceleration regime is now clear enough," Chae writes, "although the scientific community should keep gathering further evidence from future observations."

The study has been published in The Astrophysical Journal.

Part 4

**

First prehistoric people with different syndromes identified from ancient DNA

Researchers  have developed a new technique to measure the number of chromosomes in ancient genomes more precisely, using it to identify the first prehistoric person with mosaic Turner syndrome (characterized by one X chromosome instead of two [XX]), who lived about 2,500 years ago.

As part of their research published in Communications Biology, they also identified the earliest known person with Jacob's syndrome (characterized by an extra Y chromosome—XYY) in the Early Medieval Period, three people with Klinefelter syndrome (characterized by an extra X chromosome—XXY) across a range of time periods, and an infant with Down Syndrome from the Iron Age.

Most cells in the human body have 23 pairs of DNA molecules called chromosomes, and the sex chromosomes are typically XX (female) or XY (male), although there are differences in sexual development. Aneuploidy occurs when a person's cells have an extra or missing chromosome. If this occurs in the sex chromosomes, a few differences like delayed development or changes in height can be seen around puberty.

Ancient DNA samples can erode over time and can be contaminated by DNA from other ancient samples or from people handling them. This makes it difficult to accurately capture differences in the number of sex chromosomes.

The team  of researchers developed a computational method that aims to pick up more variation in sex chromosomes. For the sex chromosomes, it involves counting the number of copies of X and Y chromosomes, and comparing the outcome to a predicted baseline (what you would expect to see).

The team used the new method to analyze ancient DNA from a large dataset of individuals collected as part of their Thousand Ancient British Genomes project across British history, identifying six individuals with aneuploidies across five sites in Somerset, Yorkshire, Oxford and Lincoln (two sites). The individuals lived across a range of time periods, from the Iron Age (2,500 years ago) up to the Post-Medieval Period (about 250 years ago).

They identified five people who had sex chromosomes that fell outside the XX or XY categories. All were buried according to their society's customs, although no possessions were found with them to shed more light on their lives.

The three individuals with Klinefelter syndrome lived across very different time periods, but they shared some similarities—all were slightly taller than average and showed signs of delayed development in puberty.

By investigating details on the bones, the research team could see that it was unlikely that the individual with Turner syndrome had gone through puberty and started menstruation, despite their estimated age of 18-22. Their syndrome was shown to be mosaic; some cells had one copy of chromosome X and some had two.

Through precisely measuring sex chromosomes, they were able to show the first prehistoric evidence of Turner syndrome 2,500 years ago, and the earliest known incidence of Jacob's syndrome around 1,200 years ago. It's hard to see a full picture of how these individuals lived and interacted with their society, as they weren't found with possessions or in unusual graves, but it can allow some insight into how perceptions of gender identity have evolved over time.

 Detection of chromosomal aneuploidy in ancient genomes. Communications Biology, 2024; 7 (1) DOI: 10.1038/s42003-023-05642-z

The Key to Creating Blood Stem Cells May Lie in Your Own Blood

The development of blood stem cells relies on a seemingly unrelated microbe-sensing protein receptor, according to a new study.

The discovery could break new ground in the ongoing quest to produce blood stem cells from a person's own blood – thereby negating the need for bone marrow transplants.

The protein receptor in question, called Nod1, is already known for its role in helping recognize bacterial infections in the body and rallying an immune response, the study's authors note.

The study suggests this microbial sensor helps embryos force some of their vascular endothelial cells to become blood stem cells.

The researchers first homed in on Nod1 by analyzing public databases of human embryos, then studied the receptor further using zebrafish, a commonly used model organism that shares roughly 70 percent of its genome with humans. By inhibiting or boosting Nod1, the researchers demonstrated a positive correlation with the creation of blood stem cells.

Most of a person's blood stem cells reside in their bone marrow, so patients with certain blood disorders often need a bone marrow transplant to provide a vital supply of blood stem cells.

But armed with this evidence about Nod1's role in creating blood stem cells in embryos, scientists have new hope for devising a way to produce new blood stem cells from human samples, potentially even from patients' own blood.

That could help avoid not only the logistical challenges of arranging and performing bone marrow transplants, the researchers note, but also complications like graft-versus-host disease, in which transplanted immune cells recognize the host as foreign and attack the recipient's cells.

https://www.nature.com/articles/s41467-023-43349-1.pdf

Part 2

Water molecule discovery contradicts textbook models

Textbook models will need to be re-drawn after a team of researchers found that water molecules at the surface of salt water are organized differently than previously thought.

Many important reactions related to climate and environmental processes take place where water molecules interface with air. For example, the evaporation of ocean water plays an important role in atmospheric chemistry and climate science. Understanding these reactions is crucial to efforts to mitigate the human effect on our planet.

The distribution of ions at the interface of air and water can affect atmospheric processes. However, a precise understanding of the microscopic reactions at these important interfaces has so far been intensely debated.

In a paper published in the journal Nature Chemistry, researchers show that ions and water molecules at the surface of most salt-water solutions, known as electrolyte solutions, are organized in a completely different way than traditionally understood. This could lead to better atmospheric chemistry models and other applications.

Part 1

The researchers set out to study how water molecules are affected by the distribution of ions at the exact point where air and water meet. Traditionally, this has been done with a technique called vibrational sum-frequency generation (VSFG). With this laser radiation technique, it is possible to measure molecular vibrations directly at these key interfaces.

However, although the strength of the signals can be measured, the technique does not measure whether the signals are positive or negative, which has made it difficult to interpret findings in the past. Additionally, using experimental data alone can give ambiguous results.

The team overcame these challenges by utilizing a more sophisticated form of VSFG, called heterodyne-detected (HD)-VSFG, to study different electrolyte solutions. They then developed advanced computer models to simulate the interfaces in different scenarios.

The combined results showed that both positively charged ions, called cations, and negatively charged ions, called anions, are depleted from the water/air interface. The cations and anions of simple electrolytes orient water molecules in both up- and down-orientation. This is a reversal of textbook models, which teach that ions form an electrical double layer and orient water molecules in only one direction.
This work demonstrates that the surface of simple electrolyte solutions has a different ion distribution than previously thought and that the ion-enriched subsurface determines how the interface is organized: at the very top there are a few layers of pure water, then an ion-rich layer, then finally the bulk salt solution.

Kuo-Yang Chiang et al, Surface stratification determines the interfacial water structure of simple electrolyte solutions, Nature Chemistry (2024). DOI: 10.1038/s41557-023-01416-6. www.nature.com/articles/s41557-023-01416-6

Deadly 'Zombie Drug' Believed to Contain Human Bones Wreaks Havoc in West Africa

A new drug called kush is wreaking havoc in west Africa, particularly in Sierra Leone where it is estimated to kill around a dozen people each week and hospitalise thousands.
The drug, taken mostly by men aged 18 to 25, causes people to fall asleep while walking, to fall over, to bang their heads against hard surfaces and to walk into moving traffic.
Kush should not be confused with the drug of the same name found in the US, which is a mixture of "an ever-changing host of chemicals" sprayed on plant matter and smoked.

Kush in Sierra Leone is quite different; it is a mixture of cannabis, fentanyl, tramadol, formaldehyde and – according to some – ground down human bones.

It is mixed by local criminal gangs, but the constituent drugs have international sources, facilitated no doubt by the internet and digital communications.

While cannabis is widely grown in Sierra Leone, the fentanyl is thought to originate in clandestine laboratories in China where the drug is manufactured illegally and shipped to west Africa.

Tramadol has a similar source, namely illegal laboratories across Asia. Formaldehyde, which can cause hallucinations, is also reported in this mixture.

As for ground human bones, there is no definitive answer about whether or not they occur in the drug, where such bones would come from, or why they might be incorporated into the drug.

Some people say that grave robbers provide the bones, but there is no direct evidence of this.
But why would bones be incorporated into the drug? Some suggest that the sulphur content of the bones causes a high. Another reason might be the drug content of the bones themselves, if the deceased was a fentanyl or tramadol user.

However, both are unlikely. Sulphur levels in bones are not high. Smoking sulphur would result in highly toxic sulphur dioxide being produced and inhaled. Any drug content in bones is orders of magnitude less than that required to cause a physiological effect.
Part 1

Where is the drug found?
The drug is reported in both Guinea and Liberia, which share porous land borders with Sierra Leone, making drug trafficking easy.

Kush costs around five leones (20 UK pence) per joint, which may be used by two or three people, with up to 40 joints being consumed in a day.

This represents a massive spend on drugs and illustrates the addictive nature of the mixture, in a country where the annual income per capita is around £500.

The effects of the drug vary and depend on the user and the drug content. Cannabis causes a wide variety of effects, which include euphoria, relaxation and an altered state of consciousness.
Fentanyl, an extremely potent opioid, produces euphoria and confusion and causes sleepiness among a wide range of other side-effects.

Similarly, tramadol, which is also an opioid but less potent than fentanyl (100mg tramadol has the same effect as 10mg morphine) results in users becoming sleepy and "spaced out" – disconnected from things happening around them.

The danger of the drug is twofold: the risk of self-injury to the drug taker and the highly addictive nature of the drug itself. A further problem is the need to finance the next dose, often achieved through prostitution or criminal activity
Part 2

Joining the ranks of existing polydrugs
Kush is another example of polydrug mixtures of which forensic scientists are becoming increasingly aware. Another tobacco and cannabis-based drug, nyaope, otherwise known as whoonga, is found in South Africa.

This time the tobacco and cannabis are mixed with heroin and antiretroviral drugs used to treat Aids, some of which are hallucinogenic.

A further polydrug, "white pipe", a mixture of methaqualone (Mandrax), cannabis and tobacco, is smoked in southern Africa.

These drugs are inexpensive and provide an escape from unemployment, the drudgery of poverty, sexual and physical abuse, and the effect, in some cases, especially in west Africa, from having been a child soldier.
So what can be done about these drugs? The effectiveness of legislation alone is questionable, and many of those who attend the very limited rehabilitation centres return to drug use.

Perhaps what is required is an integrated forensic healthcare system where legislative control is backed up by properly resourced rehabilitation centres coupled with a public health and employment programme. What changes are made in response to this epidemic remains to be seen.

Michael Cole, Professor of Forensic Science, Anglia Ruskin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Part 3

**

Scientists Film Plant 'Talking' to Its Neighbour

Imperceptible to us, plants are surrounded by a fine mist of airborne compounds that they use to communicate and protect themselves. Kind of like smells, these compounds repel hungry herbivores and warn neighboring plants of incoming assailants.

Scientists have known about these plant defenses since the 1980s, detecting them in over 80 plant species since then. Now, a team of Japanese researchers has deployed real-time imaging techniques to reveal how plants receive and respond to these aerial alarms.

This was a big gap in our understanding of plant chatter: we knew how plants send messages, but not how they receive them.

In this study, Yuri Aratani and Takuya Uemura, molecular biologists at Saitama University in Japan, and colleagues rigged up a pump to transfer compounds emitted by injured and insect-riddled plants onto their undamaged neighbors, and a fluorescence microscope to watch what happened.

Caterpillars (Spodoptera litura) were set upon leaves cut from tomato plants and Arabidopsis thaliana, a common weed in the mustard family, and the researchers imaged the responses of a second, intact, insect-free Arabidopsis plant to those danger cues.

These plants weren't any ordinary weeds: they had been genetically altered so their cells contained a biosensor that fluoresced green when an influx of calcium ions was detected. Calcium signaling is something human cells use to communicate too.

The team used a similar technique to measure calcium signals in a study last year of fluorescent Mimosa pudica plants, which quickly move their leaves in response to touch, to avoid predators.

This time, the team visualized how plants responded to being bathed in volatile compounds, which plants release within seconds of wounding.

Part 2

It wasn't a natural set-up; the compounds were concentrated in a plastic bottle and pumped onto the recipient plant at a constant rate, but this allowed the researchers to analyze what compounds were in the pungent mix.

As you can see in the video above, the undamaged plants received the messages of their injured neighbors loud and clear, responding with bursts of calcium signaling that rippled across their outstretched leaves.

Analyzing the airborne compounds, the researchers found that two compounds called Z-3-HAL and E-2-HAL induced calcium signals in Arabidopsis.

They also identified which cells are the first to respond to the danger cues by engineering Arabidopsis plants with fluorescent sensors exclusively in guard, mesophyll, or epidermal cells.

Guard cells are bean-shaped cells on plant surfaces that form stomata, small pores that open up to the atmosphere when plants 'breathe' in CO2. Mesophyll cells are the inner tissue of leaves, and epidermal cells are the outermost layer or skin of plant leaves.

When Arabidopsis plants were exposed to Z-3-HAL, guard cells generated calcium signals within a minute or so, after which mesophyll cells picked up the message.

What's more, pre-treating plants with a phytohormone that shuts stomata significantly reduced calcium signaling, suggesting stomata act as the 'nostrils' of the plant.
part 3

"We have finally unveiled the intricate story of when, where, and how plants respond to airborne 'warning messages' from their threatened neighbors," says Masatsugu Toyota, a molecular biologist at Saitama University in Japan and senior author of the study.

"This ethereal communication network, hidden from our view, plays a pivotal role in safeguarding neighboring plants from imminent threats in a timely manner."

The study has been published in Nature Communications.

https://www.sciencealert.com/scientists-film-plant-talking-to-its-n...

Part 4

**

UK-wide study reveals harm done by people not getting COVID jabs

More than 7,000 people were hospitalized or died from COVID-19 in the UK during the summer of 2022 because they had not received the recommended number of vaccine doses, according to a study released Tuesday that was the first to cover Britain's entire population.

The researchers said the "landmark" population-wide study showed how important it is for people to keep getting booster jabs as COVID continues to pose a major health threat. More than 90 percent of the UK's adult population were vaccinated during the earlier stages of the pandemic. However, between June to September 2022, after the pandemic's emergency phase was declared over and attention turned elsewhere, around 44 percent of Britons were under-vaccinated, the researchers said. Using individual health data from the National Health Service (NHS) as well as modeling, the researchers estimated that there would have been 7,180 fewer hospitalizations or deaths if everyone had been up to date with their shots. That means that nearly 20 percent of the 40,000 COVID hospitalizations or deaths over the summer could have been avoided if Britons were fully vaccinated.

Undervaccination and severe COVID-19 outcomes: meta-analysis of national cohort studies in England, Northern Ireland, Scotland, and Wales, The Lancet (2024). DOI: 10.1016/S0140-6736(23)02467-4 , www.thelancet.com/journals/lan … (23)02467-4/fulltext

Amnesia caused by head injury reversed in early mouse study

A mouse study designed to shed light on memory loss in people who experience repeated head impacts, such as athletes, suggests the condition could potentially be reversed. The research in mice finds that amnesia and poor memory following head injury are due to inadequate reactivation of neurons involved in forming memories.

The study, conducted by researchers is reported January 16, 2024, in The Journal of Neuroscience.

Importantly for diagnostic and treatment purposes, the researchers found that the memory loss attributed to head injury was not a permanent pathological event driven by a neurodegenerative disease. Indeed, the researchers could reverse the amnesia to allow the mice to recall the lost memory, potentially allowing cognitive impairment caused by head impact to be clinically reversed.
The  investigators had previously found that the brain adapts to repeated head impacts by changing the way the synapses in the brain operate. This can cause trouble in forming new memories and remembering existing memories. In their new study, investigators were able to trigger mice to remember memories that had been forgotten due to head impacts.

 Amnesia after repeated head impact is caused by impaired synaptic plasticity in the memory engram, The Journal of Neuroscience (2024).

Energy-starved breast cancer cells consume their surroundings for fuel, research suggests

Breast cancer cells ingest and consume the matrix surrounding them to overcome starvation, according to a new study published January 16 in the open access journal PLOS Biology. The finding elucidates a previously unknown mechanism of cancer cell survival, and may offer a new target for therapy development.

Cells in the breast, including tumor cells, are embedded in a meshwork called the extracellular matrix (ECM). Nutrients are scarce in the ECM, due to limited blood flow, and become even scarcer as tumor cells grow. And yet they continue to grow, leading the authors to investigate how tumor cells supply themselves with the raw materials to support that growth. To do so, they seeded breast adenocarcinoma cells into either collagen (a major component of the ECM) or a commercial matrix preparation, or onto plastic, with or without certain critical amino acids. Without those amino acids, cells on plastic fared poorly compared to those in one or the other matrix. Similar results were seen with other matrix models—the tumor cells were able to overcome the reduction of amino acids when surrounded by matrix. Next, by fluorescently labeling the collagen and watching its journey through the cell, the authors showed that the cells took up ECM and broke it down in digestive compartments called lysosomes; when the ECM was chemically treated to cross-link its components, the cells were unable to ingest it. Further investigation indicated that uptake was through an ingestion process called macropinocytosis, in which the cell engulfs large quantities of extracellular material. What were the tumor cells after? Analysis of their metabolome indicated that procurement and breakdown of two amino acids, tyrosine and phenylalanine, dominated the metabolic changes in response to starvation. The authors noted that these two can serve as the raw material for energy production through the mitochondrial tricarboxylic acid (Krebs) cycle. When they knocked down HPDL, a central enzyme in the pathway from phenylalanine to the TCA, cell growth was significantly impaired. Blocking or reducing expression of HPDL, or the macropinocytosis promoter PAK1, reduced the ability of tumor cells to migrate and to invade surrounding tissue. These results indicate that breast cancer cells take advantage of nutrients in the extracellular matrix in times of nutrient starvation, and that this process depends on both macropinocytosis and metabolic conversion of key amino acids to energy-releasing substrates.

Nazemi M, Yanes B, Martinez ML, Walker HJ, Pham K, Collins MO, et al. (2024) The extracellular matrix supports breast cancer cell growth under amino acid starvation by promoting tyrosine catabolism. PLoS Biology (2024). DOI: 10.1371/journal.pbio.3002406

Soldering wounds with light and nano thermometers

Not every wound can be closed with needle and thread. Researchers have now developed a soldering process with nanoparticles that gently fuses tissue. The soldering technique is expected to prevent wound healing disorders and life-threatening complications from leaking sutures.

Some time more than 5,000 years ago, humankind came up with the idea of suturing a wound with a needle and thread. Since then, this surgical principle has not changed much: Depending on the fingertip feeling of the person performing the operation and the equipment, cuts or tears in the tissue can be joined together more or less perfectly. Once both sides of a wound are neatly fixed to each other, the body can begin to close the tissue gap permanently in a natural way.

However, the suture does not always achieve what it is supposed to. In very soft tissues, the thread can cut through the tissue and cause additional injury. And if the wound closure does not seal on internal organs, permeable sutures can pose a life-threatening problem. Researchers have now found a way to solder wounds using lasers.

Soldering usually involves joining materials together by means of heat via a melting bonding agent. The fact that this thermal reaction must remain within narrow limits for biological materials and at the same time the temperature is difficult to measure in a non-invasive way has been a problem for the application of soldering processes in medicine.

The researchers tinkered with a smart wound closure system in which laser soldering can be controlled gently and efficiently. For this purpose, they developed a bonding agent with metallic and ceramic nanoparticles and used nanothermometry to control the temperature.

The elegance of the new soldering process is also based on the interaction of the two types of nanoparticles in the bonding protein-gelatin paste. While the paste is irradiated by laser, titanium nitride nanoparticles convert the light into heat. The specially synthesized bismuth vanadate particles in the paste, on the other hand, act as tiny fluorescent nano thermometers. They emit light of a specific wavelength in a temperature-dependent manner, allowing extremely precise temperature regulation in real time.

This makes the method particularly suitable for use in minimally invasive surgery, as it does not require stirring and determines temperature differences with extremely fine spatial resolution in superficial and deep wounds.

The researchers also succeeded in replacing the laser light source with gentler infrared (IR) light. This brings the soldering technology another step closer to be used in hospitals.

Oscar Cipolato et al, Nanothermometry‐Enabled Intelligent Laser Tissue Soldering, Small Methods (2023). DOI: 10.1002/smtd.202300693

Scientists report fundamental asymmetry between heating and cooling

A new study  by scientists has found a fundamental asymmetry showing that heating is consistently faster than cooling, challenging conventional expectations and introducing the concept of "thermal kinematics" to explain this phenomenon. The findings are published in Nature Physics.

Traditionally, heating and cooling, fundamental processes in thermodynamics, have been perceived as symmetric, following similar pathways.

On a microscopic level, heating involves injecting energy into individual particles, intensifying their motion. On the other hand, cooling entails the release of energy, dampening their motion. However, one question has always remained: Why is heating more efficient than cooling?

To answer this questions, researchers have introduced a new framework: thermal kinematics.

Part 1

At the microscopic level, heating and cooling are processes involving the exchange and redistribution of energy among individual particles within a system.

In heating, energy is injected into each particle of a system, leading to an intensification of the particles' motion. This causes them to move more vigorously. The higher the temperature, the more intense the Brownian (or random) motion of these particles due to increased collisions with surrounding water molecules.

On the other hand, cooling at the microscopic level involves the release of energy from individual particles, resulting in a dampening of their motion. This process corresponds to the system losing energy, leading to a decrease in the intensity of particle movement.

Researchers took an object from a boiling-water bath (at 100 degrees Celsius) and immersing it in a mixture of water and ice (at 0 degrees Celsius)."

They compared how fast the system equilibrates with the reverse protocol when the object is initially in the cold bath and heated in boiling water. They observed that, at the microscale, heating is faster than cooling, and they explained this theoretically by developing a new framework they call thermal kinematics.

Part 2

The researchers employed a sophisticated experimental setup to observe and quantify the dynamics of microscopic systems undergoing thermal relaxation. At the heart of their experimentation were optical tweezers—a powerful technique using laser light to capture single microparticles made of silica or plastic.

"These tiny objects move in an apparently random fashion due to the collisions with water molecules, executing the so-called Brownian motion while they are confined to a small region by tweezers. The higher the temperature of the water, the more intense the Brownian motion will be due to more frequent and intense collisions with water molecules.

To induce thermal changes, the researchers subjected the confined microparticles to varying temperatures. They carefully controlled the temperature of the surrounding environment using a noisy electrical signal, simulating a thermal bath.

This experimental device allows the physicists to track the motion of the particle with exquisite precision, giving access to these previously unexplored dynamics.

By manipulating the temperature and observing the resulting movements, the team gathered crucial data to understand the intricacies of heating and cooling at the microscale level.

The development of the theoretical framework (thermal kinematics) played a pivotal role in explaining the observed phenomena. This framework combined principles from stochastic thermodynamics—a generalization of classical thermodynamics to individual stochastic trajectories—with information geometry.

Thermal kinematics provided a quantitative means to elucidate the observed asymmetry between heating and cooling processes. This allowed the researchers not only to validate theoretical predictions but also to explore the dynamics between any two temperatures, revealing a consistent pattern of heating being faster than cooling.

M. Ibáñez et al, Heating and cooling are fundamentally asymmetric and evolve along distinct pathways, Nature Physics (2024). DOI: 10.1038/s41567-023-02269-z

Part 3

The world smells different for female silk moths than for males

A team of researchers  has studied olfaction in female silk moths. Using electrophysiological methods, they discovered that the antenna, which is specialized in males to detect female pheromones, is particularly sensitive to the scent of silkworm excrement in females.

Components of this scent turned out to be a deterrent for mated females, probably allowing them to avoid competition for their own offspring when laying eggs. The responsible sensory neurons are located in hair-like structures called sensilla.
In males, the detection of pheromones takes place in a long type of these sensilla, whereas the long sensilla neurons of females detect the odor of larval excrement. The odor of the mulberry tree, the only silkworm host plant, on the other hand, is detected by the female silk moths' sensory neurons in medium-length sensilla.
In humans, the sense of smell is similarly developed in men and women, although women have slightly more olfactory neurons and therefore a slightly more sensitive nose. On the whole, however, they perceive the same odors. Male moths, on the other hand, live in a completely different olfactory world to their female counterparts. For example, the antennae of male silk moths—their "nose"—are highly specialized to detect female sex pheromones, while females cannot even smell their own pheromones.

Females smell differently: characteristics and significance of the most common olfactory sensilla of female silkmoths, Proceedings of the Royal Society B: Biological Sciences (2024). DOI: 10.1098/rspb.2023.2578. royalsocietypublishing.org/doi … .1098/rspb.2023.2578

Study finds microplastics from natural fertilizers are blowing in the wind more often than once thought

Though natural fertilizers made from treated sewage sludge are used to reintroduce nutrients onto agricultural fields, they bring along microplastic pollutants too. And according to a small-scale study published in Environmental Science & Technology Letters, more plastic particles get picked up by the wind than once thought. Researchers have discovered that the microplastics are released from fields more easily than similarly sized dust particles, becoming airborne from even a slight breeze.

Microplastics, or small bits of plastic less than 5 millimeters long, have appeared everywhere from clouds to heart tissues. And with these plastics' increasing prevalence in people and water supplies, they've also been found in sewage and wastewater.

Though sewage solids might not immediately seem like a useful product, after treatment they can form "biosolids," which are applied to agricultural soils as a natural, renewable source of fertilizer.
According to estimates by the U.S. Environmental Protection Agency, over 2 million dry metric tons of biosolids—roughly half of the total amount collected by wastewater treatment plants—are applied to land each year.

As a result, microplastics in these biosolids have the chance to reenter the environment. Because the plastics could carry other pollutants from the wastewater they originated from, they can be potentially dangerous when inhaled.
Researchers analyzed airborne microplastics in wind-blown sediments that were gathered during wind-tunnel experiments on two plots of biosolid-treated land in rural areas.
The researchers discovered that these wind-blown sediments contained higher concentrations of microplastics than either the biosolids or the source soil itself. This enrichment effect is caused by the plastic particles being less dense than soil minerals, such as quartz, and less "sticky"—they're not trapped as easily by moisture as the soil minerals are.

As a result, microplastics can be picked up by a breeze more easily than soil minerals, and winds that might not be strong enough to kick up dust could still be introducing microplastics into the air.

The researchers say that previous models did not take this sticky effect and other unique properties of microplastics into account when estimating emissions from treated fields. Therefore, these older models are likely to underestimate the actual amount of plastic particles released into the air.
The present work indicate that microplastics may be emitted from barren agricultural fields from nearly two and a half times more wind events than previously estimated.

 Preferential Emission of Microplastics from Biosolid-Applied Agricultural Soils: Field Evidence and Theoretical Framework, Environmental Science & Technology Letters (2024). DOI: 10.1021/acs.estlett.3c00850

Indian Tectonic Plate Is Splitting in Two Beneath Tibet, Latest Analysis Finds

The engines driving the growth of the world's highest mountains into the sky run deep beneath the planet's skin. Geologists have some idea of the mechanisms at work, but evidence has so far left plenty of room for debate over the details.

Combined with a fresh look at previous research, a recent analysis of new seismic data collected from across southern Tibet has delivered a surprising depiction of the titanic forces operating below the Himalayas.

Presenting at the American Geophysical Union conference in San Francisco last December, researchers from institutions in the US and China described a disintegration of the Indian continental plate as it grinds along the basement of the Eurasian tectonic plate that sits atop it. It's a surprising compromise on two models currently favored as explanations for the lifting of the Tibetan plateau and the colossal Himalayan mountain range.

In both cases, a collision between the chunks of crust belonging to India and Eurasia is responsible. Starting around 60 million years ago, the Indian plate was driven beneath its northern neighbor as it was carried along by currents of molten rock within the mantle.

Bit by bit, the Eurasian land mass has been lifted skyward on the shoulders of a drowned giant, giving us Earth's highest elevations.

Studies of the density of the mantle and the crust suggest the rather buoyant Indian continental plate shouldn't sink so easily, however, meaning it's likely the submerged sections of the crust should still be grinding along under the belly of the Eurasian plate rather than being plunged into the mantle's depths.

Another possibility is the Indian plate is distorting in a way that causes some parts to wrinkle and fold, and others to dip and dive.

Different perspectives emerge depending on which kinds of evidence are favored and how data is processed.

Part 1

In an investigation led by Ocean University of China geophysicist Lin Liu, researchers amassed 'up-and-down' S-wave and shear-wave splitting data from 94 broadband seismic stations arranged west-to-east across southern Tibet, and combined it with previously collected 'back-and-forth' P-wave data to come up with a more nuanced view of the dynamics below.

They determined the Indian slab wasn't merely bobbing along smoothly below the Eurasian plate, nor was it bunching up like a rug on a slippery floor.

Instead it is delaminating, with its dense base peeling free and sinking into the mantle as its lighter top-half continued its journey just beneath the surface.

While computer models had suggested thicker sections of some plates could come apart like this, the study provides the first empirical evidence of it occurring.

The team's description is consistent with geological models based on limits of helium-3 enriched spring water and patterns of fractures and earthquakes near the surface, which taken together support a map of carnage below, where sections of the old Indian plate seem more or less intact, and others are stripping apart around 100 kilometers below, allowing the base to warp into the planet's molten heart.

Having a clear 3D description of the boundaries and borders of plates as they grind together not only makes it easier to understand how our surface came to look as it does, but could inform future methods of earthquake prediction.

The study was presented at the 2023 American Geophysical Union conference. A pre-print copy of the study is available online.

https://www.sciencealert.com/indian-tectonic-plate-is-splitting-in-...

Part 2

**

Gut Bacteria Is Surprisingly Resilient to Antibiotics, Long-Term Study Shows

Antibiotic resistance is causing us all sorts of havoc. It's turning once manageable pathogens into superbugs, hitting our most vulnerable people the hardest. Superbugs were involved with nearly 5 million deaths globally in 2019, so antibiotic resistance is generally not something we at all want to promote in the slightest. But while it's boosting our bacterial nemeses, resistance factors mean our good bacteria are becoming more resistant to antibiotics as well. A new study has found antibiotic resistance genes is also giving our gut bacteria an advantage, allowing them stay on top in their never ending battle against microbes that cause us harm. Antimicrobial resistance mutations in commensals can have paradoxically beneficial effects by promoting microbiome resilience to antimicrobials. researchers investigated the war between good and bad gut bacteria within 24 patients who have multidrug-resistant tuberculosis (Mycobacterium tuberculosis), detailing the battle in a blow-by-blow account. The patients had received numerous types of antibiotics to keep their illness at bay, a regime they were required to maintain for 20 months. Treatment initially devastated their gut microbiomes, causing disruptions in the metabolism, composition, and diversity of bacterial species. Unpleasant side effects included diarrhea and gut inflammation, which isn't surprising given antibiotic use has also been linked to increased cases of irritable bowel syndrome. Yet over time, something rather surprising was observed among the patients. The study findings document an unexpected resilience of the microbiome to disruption by long-term antibiotics, write the researchers, explaining how the microbiomes in the patients spontaneously reestablished the dominance of friendly bacteria in the wake of initial imbalance.

Part 1

What's more, they found the state of the patient's gut microbiome as well as the clearance of the tuberculosis bacteria itself are linked to recovery from tuberculosis-driven inflammation. Blooms of bacteria from the Enterobacteriaceae family post-treatment led to more widespread inflammation, whereas microbiomes with more Clostridia and fewer Enterobacteriaceae were associated with a faster drop in the inflammation that drives tuberculosis symptoms.

Further tests in mice involving fecal transplants from the patients revealed their microbiomes had acquired a resistance to subsequent antibiotic disruption. These resistance genes were still seen in some of the friendly bacterial species a year after antibiotic treatments had ceased in the mice.
These mutations may have a fitness benefit in the microbiome ecosystem established by long-term antibiotics.

https://www.science.org/doi/10.1126/scitranslmed.adi9711

part 2

Researchers discover rare phages that attack dormant bacteria

In nature, most bacteria live on the bare minimum. If they experience nutrient deficiency or stress, they shut down their metabolism in a controlled manner and go into a resting state. In this stand-by mode, certain metabolic processes still take place that enable the microbes to perceive their environment and react to stimuli, but growth and division are suspended.

This also protects bacteria from, say, antibiotics or from viruses that prey exclusively on bacteria. Such bacteria-infecting viruses, known as phages, are considered a possible alternative to antibiotics that are no longer (sufficiently) effective due to drug resistance. Until now, expert consensus held that phages successfully infect bacteria only when the latter are growing.

Then researchers asked themselves now whether evolution might have produced bacteriophages that specialize in dormant bacteria and could be used to target them. They began their search in 2018. Now, in a new publication in the journal Nature Communications, they show that such phages, though rare, do indeed exist.

They found them first in rotting plant material and this virus can infect and destroy dormant bacteria. This is the first phage described in the literature that has been shown to attack bacteria in a dormant state. They have named their new phage Paride.

The virus the researchers found infects Pseudomonas aeruginosa, a bacterium commonly found in many environments. Various strains colonize bodies of water, plants, the soil—and people. In the human body, certain strains can cause serious respiratory diseases such as pneumonia, which can be fatal. How the new phage takes dormant P. aeruginosa germs by surprise, however, is not yet clear to the researchers. They suspect that the virus uses a specific molecular key to awaken the bacteria, and then hijacks the cell's multiplication machinery for its own reproduction. However, the researchers have not yet been able to clarify exactly how this works.

They now aim to elucidate the genes or molecules that underlie this awakening mechanism. Based on this, they could develop substances in a test tube that take over the wake-up process. Such a substance could then be combined with a suitable antibiotic that completely eliminates the bacteria.

Part 1

To test the efficacy of the Paride phage, the researchers paired it with an antibiotic called meropenem. This disrupts cell wall synthesis and so it interferes only with cellular processes that don't damage the phages. The antibiotic has no effect on dormant bacteria, as these don't synthesize a new cell wall.

When tested in cell culture dishes, the virus was able to kill 99% of all dormant bacteria but left 1% alive. Only the combination of Paride phages and meropenem was able to eradicate the bacterial culture completely, even though the latter had no detectable effect on its own.

In a further experiment  other researchers tested this combination on mice with a chronic infection. Neither the phage nor the antibiotic alone worked particularly well in the mice, but the interaction between phages and antibiotics proved to be very effective in living organisms as well.

In the case of chronic infections, that means it would be important to know the physiological state of the bacteria in question. Then the right phages, combined with antibiotics, could be used in a targeted manner. However, you need to know exactly how a phage attacks a bacterium before you can select the right phages for a particular treatment.

The researchers will now investigate precisely how the new phage brings bacteria out of deep sleep, infects them and makes them susceptible to antibiotics.

Enea Maffei et al, Phage Paride can kill dormant, antibiotic-tolerant cells of Pseudomonas aeruginosa by direct lytic replication, Nature Communications (2024). DOI: 10.1038/s41467-023-44157-3

Energy supply in human cells is subject to quality control, researchers discover

Researchers have discovered a new quality control mechanism that regulates energy production in human cells. This process takes place in mitochondria, the power plants of the cell.

Malfunctions of mitochondria lead to serious diseases of the nerves, the muscles and the heart. The findings could contribute to the development of new therapies for affected patients. The results have been published in Molecular Cell.

Mitochondria play a central role for cellular metabolism. Therefore, malfunctions of the mitochondria lead to serious, often fatal, heart, muscle or nerve diseases. Mitochondria are surrounded by two membranes, an outer and an inner one, which separate them from the surrounding cell. The final conversion of food into energy takes place in the inner membrane. Proteins are involved in this process. Central proteins for energy production are formed in the mitochondria, transported to the inner membrane and inserted there.

The protein OXA1L is mainly responsible for the insertion of proteins into the membrane, where larger complex structures are formed with other proteins that interact with each other and ensure energy production. How the incorporation and assembly of these structures works in detail has been poorly investigated thus far.

Scientists have now discovered that the process of energy production depends on the interaction of the protein OXA1L with the protein TMEM126A.

If TMEM126A is missing, a quality control mechanism is activated in the inner membrane of the mitochondria, which ensures that OXA1L and proteins newly generated for the energy production machinery are degraded and thus cannot be incorporated into the membrane. This shows that the protein TMEM126A is critical for energy production in mitochondria. "This finding is an important step in the search for new therapeutic approaches for affected patients. Understanding how proteins interact with each other in mitochondria could help to identify the causes of certain diseases. If we know what is missing in the cell or which process is not working properly in certain diseases, we can develop treatment measures to 'repair' this defect.

Sabine Poerschke et al, Identification of TMEM126A as OXA1L-interacting protein reveals cotranslational quality control in mitochondria, Molecular Cell (2024). DOI: 10.1016/j.molcel.2023.12.013

Bugs as Drugs to Boost Cancer Therapy

Bioengineered bacteria sneak past solid tumor defenses to guide CAR T cells’ attacks.

n the 1890s, physician William Coley injected patients who had cancer with bacteria after learning about patients who experienced spontaneous tumor regression following a concurrent bacterial infection.  He was one of the first scientists to link immune system activation with an antitumor response, which earned him the appellation, “the father of immunotherapy.” Despite some successes in the clinic, safety concerns and the rise of radiotherapy caused these bacterial elixirs, known as Coley’s toxins, to fall by the wayside.

Over the last few decades, advancements across immunology, microbiology, and synthetic biology renewed interest in bioengineering bugs for cancer therapies. In a paper published in Science, researchers designed probiotics to colonize tumors and guide engineered T cells to the cancer site.

 Their novel platform not only shows that engineered bacteria can help existing immunotherapies gain access to difficult-to-treat solid tumors, but also highlights the broader potential of living drugs.

Part 1

The tumour microenvironment is an inhospitable ecosystem. “For bacteria, they kind of don't care about all of that. They are really, at a very general level, looking for a place where they can survive in the body that's away from the immune system.

The hypoxic, minimally surveilled core of a solid tumor is the perfect bacterial bungalow. However, some bacterial strains can still inhabit healthy organs, so researchers need to explore ways to modify the bacterial genome to reduce virulence and toxicity. Although attenuated bacteria proved safer in both mice and humans, researchers observed poor tumor colonization and no tumor regression. Now, to improve tumor targeting and specificity, researchers are searching for synthetic biology solutions.

Bacteria already have a proclivity for the tumor microenvironment.

So researchers engineered the probiotic strain Escherichia coli Nissle 1917, which was equipped with Danino’s quorum sensing lysis circuit. Once the bacteria reached quorum, they released synthetic antigens that stuck to the tumor. Specifically, the researchers fused a green fluorescent protein (GFP) to the heparin binding domain (HBD) of a placental growth factor protein.¹⁰ The sticky HBD anchored to collagens and polysaccharides, ubiquitous components in the tumor environment, thus planting GFP flags on the tumor. Although these molecules are found in healthy tissue, they are highly abundant in the tumour.

Part 2

This time researchers designed their CAR to target their synthetic GFP antigen.

When they tested their probiotic CAR system in vitro using different human cancer cell lines, the researchers observed increased specificity and cytotoxicity relative to systems lacking either the GFP tag or receptor. Following the in vitro inspections, their system was ready to leave the garage and hit the road.

For the first in vivo test of their probiotic CAR platform, the researchers turned to immunodeficient mice bearing subcutaneous tumors derived from human cancer cells. After injecting the engineered bacteria directly into the tumor, they waited 48 hours to allow for quorum-regulated release of the GFP tags before similarly delivering the engineered CAR.¹¹ The engineered probiotic CAR system inhibited tumor growth, and subsequent flow cytometry analyses of the tumors provided evidence of increased T cell activation. 

The researchers also found that a partial system produced a partial response: empty bacteria administered alongside the engineered CAR still triggered some T cell activation at the tumor site. The best part of the system is the fact that the T cells respond really strongly to bacteria.

Part 3

To increase CAR T cell proliferation and persistence, patients must first undergo lymphodepletion to kill circulating T cells. However, a long-term goal of immunotherapies is to administer the treatment to an intact immune system. 

To test their system on a functioning immune system, the researchers implanted mouse-derived tumors on both hind flanks of immune-competent mice and then administered the engineered bacteria directly to one of the tumor sites, followed a few days later by two rounds of CAR T treatment. (They introduced an extra dose of CAR T cells to combat T cell exhaustion.) The researchers hoped that their system could generate enough inflammation to stimulate the host immune system to recognize the additional tumor, so they were excited to find a reduction in tumor growth in not only the treated tumor but also the untreated site.

The subcutaneous experiments prepared for the big experiment: intravenous administration of the probiotic CAR system. For this, they implanted human cancer cells into the mammary fat pads of mice with weakened immune systems and then administered the probiotic CAR regimen with one small tweak to the system. In order to further coax the CAR T cells to the tumor site, the researchers engineered the bacteria to corelease the immune cell attractant human chemokine ligand 16 (CXCL16).¹³ This paved a concentration gradient for the CAR T cells to drive along towards the tumor. The added chemokine cargo added a boost to the system, outperforming the standard probiotic CAR regimen with respect to tumor growth inhibition. Additionally, analyses of other organs showed that bacteria and GFP expression was restricted to the tumor site.

Before transitioning these experiments to humans, the researchers will first need to genetically attenuate their engineered bacteria. In this study, they used a wild type strain of E coli, but mice are less sensitive than humans to Gram-negative bacteria toxicity. The major focus of the lab now is trying to make a translational strain of bacteria.

Part 4

A synthetic space for the growth of bacterial therapies 

This is an example of how two different engineered systems can be complementary and synergize their function.

 Beyond remodeling the tumor environment to boost CAR T efficacy, researchers are exploring how engineered bacteria can enhance positron emission tomography (PET)/magnetic resonance imaging (MRI), focus ultrasounds, and even deliver drug-loaded nanoparticles

https://www.the-scientist.com/news/bugs-as-drugs-to-boost-cancer-th...

Part 5

**

Scientists spin naturalistic silk from artificial spider gland

Researchers have succeeded in creating a device that spins artificial spider silk that closely matches what spiders naturally produce. The artificial silk gland was able to re-create the complex molecular structure of silk by mimicking the various chemical and physical changes that naturally occur in a spider's silk gland.

This eco-friendly innovation is a big step towards sustainability and could impact several industries.

Famous for its strength, flexibility, and light weight, spider silk has a tensile strength that is comparable to steel of the same diameter, and a strength-to-weight ratio that is unparalleled. Added to that, it's biocompatible, meaning that it can be used in medical applications, as well as biodegradable. So why isn't everything made from spider silk? Large-scale harvesting of silk from spiders has proven impractical for several reasons, leaving it up to scientists to develop a way to produce it in the laboratory.

Spider silk is a biopolymer fiber made from large proteins with highly repetitive sequences, called spidroins. Within the silk fibers are molecular substructures called beta sheets, which must be aligned properly for the silk fibers to have their unique mechanical properties. Re-creating this complex molecular architecture has confounded scientists for years. Rather than trying to devise the process from scratch, scientists now took a biomimicry approach.

They  attempted to mimic natural spider silk production using microfluidics, which involves the flow and manipulation of small amounts of fluids through narrow channels. Indeed, one could say that the spider's silk gland functions as a sort of natural microfluidic device.

The device developed by the researchers looks like a small rectangular box with tiny channels grooved into it. Precursor spidroin solution is placed at one end and then pulled towards the other end by means of negative pressure. As the spidroins flow through the microfluidic channels, they are exposed to precise changes in the chemical and physical environment, which are made possible by the design of the microfluidic system. Under the correct conditions, the proteins self-assembled into silk fibers with their characteristic complex structure.

The researchers experimented to find these correct conditions, and eventually were able to optimize the interactions among the different regions of the microfluidic system. Among other things, they discovered that using force to push the proteins through did not work; only when they used negative pressure to pull the spidroin solution could continuous silk fibers with the correct telltale alignment of beta sheets be assembled.

The ability to artificially produce silk fibers using this method could provide numerous benefits. Not only could it help reduce the negative impact that current textile manufacturing has on the environment, but the biodegradable and biocompatible nature of spider silk makes it ideal for biomedical applications, such as sutures and artificial ligaments.

Jianming Chen et al, Replicating shear-mediated self-assembly of spider silk through microfluidics, Nature Communications (2024). DOI: 10.1038/s41467-024-44733-1

Just One Molecule Allows Us to See Millions More Colors Than Our Pets

It's pretty hard to imagine the world through someone else's eyes, especially different animals. But a new study using lab-grown human retinas reveals that even between different humans, our vision is extremely diverse. And it might be to do with how the red and green cones form in our retinas. Cones are light-sensing cells in vertebrates' eyes; their combined responses to different wavelengths enable color vision.

Humans and some closely related primates are some of the only mammals known that can see the color red, as well as green and blue.

Other animals can also see red, like many birds and some insects. The kind of vision an animal has is closely related to its evolution alongside plants that produce fruits and flowers. This ability has been pretty useful, for instance, for spotting a ripe red apple among a dense canopy of green.

Another mammal outlier with the ability to see red is the honey possum (Tarsipes rostratus). This Australian marsupial pollinator has a bird-like ability to probe the nectar from a blushing banksia, in a fascinating example of convergent evolution.

Our red and green cones are basically identical, with slightly different chemistry to determine which color they'll detect. A protein called opsin comes in two different 'flavors', red-sensitive or green-sensitive, and their genetic 'recipes' sit side-by-side on the X chromosome.

So it's very easy for them to get mixed up in recombination, resulting in variations of congenital red-green color blindness.
Part 1

Now, new research offers some clarity as to what those key vision-defining ingredients – making up just a 4 percent difference between the genes that code for these proteins – actually are.
We previously thought cone determination was basically random, though more recent studies have pointed to thyroid levels playing a role.

But a team from Johns Hopkins University and the University of Washington has discovered that levels of a molecule derived from vitamin A called retinoic acid make or break red-green cone ratios, at least in the case of their lab-grown retinas.

"These retinal organoids allowed us for the first time to study this very human-specific trait," says developmental biologist Robert Johnston from Johns Hopkins University. "It's a huge question about what makes us human, what makes us different."

In the lab, retinas exposed to more retinoic acid during early development (the first 60 days) resulted in higher ratios of green cones across the organoid after 200 days, while immature cones exposed to low levels of the acid developed into red cones later on.

The timing matters, too. If the retinoic acid was introduced at 130 days onwards, the effect was the same as if none had been added at all. This suggests the acid determines cone type early, and can't cause red cones to 'switch' into green cones that have already matured.

All the lab-grown retinas had similar cone densities, which allowed the team to rule out cone cell death as affecting the ratio of red to green.
part 2

Developmental biologist Sarah Hadyniak, who co-authored the study while at Johns Hopkins University, says their findings have implications for figuring out exactly how retinoic acid is acting on genes.

To get a sense of how much this could be affecting human vision, the researchers studied the retinas of 738 male adults with no signs of color vision deficiency.

The researchers were astonished at the natural variation in red/green cone ratio across this group.

"Seeing how the green and red cone proportions changed in humans was one of the most surprising findings of the new research", Hadyniak says.

It's unclear how this much variation could occur without affecting changes in vision. As Johnston put it, "if these types of cells determined the length of a human arm, the different ratios would produce amazingly different arm lengths."

This research was published in PLOS Biology.
Part 3
**

Chemists tie a knot using only 54 atoms

A trio of chemists  has tied the smallest knot ever, using just 54 atoms. In their study, published in the journal Nature Communications, the researchers accidentally tied the knot while trying to create metal acetylides in their lab.

The researchers were attempting to create types of alkynes called metal acetylides as a means to conduct other types of organic reactions. More specifically, they were attempting to connect carbon structures to gold acetylides—typically, such work results in the creation of simple chains of gold known as caternames.
But, unexpectedly, the result of one reaction created a chain that knotted itself into a trefoil knot with no loose ends. Trefoil knots are used in making pretzels and play a major role in knot theory. The researchers noted that the knot had a backbone crossing ratio (BCR) of 23. Knot BCRs are a measure of the strength of the knot. Most organic knots, the team notes, have a BCR somewhere between 27 and 33.

The knot represents a record—its three-leaf clover shape beats out a previous record held by a different team in China that created a 69-atom knot back in 2020. The prior record holder was created on purpose by that team using techniques developed to entwine strands into knots. The new record holder self-assembled, and the team behind it still does not understand how it happened. It is not yet known if it is possible to make a knot any smaller.

The creation of such tiny knots, the research team points out, is not just an interesting lab trick—microscopic knots are formed in many natural settings, such as in RNA and DNA and several other proteins. By creating tiny knots, chemists are learning more about how and why they come about in nature. It also could help in the discovery of new types of polymers and/or plastics.

Cells' electric fields keep nanoparticles at bay, scientists confirm

The humble membranes that enclose our cells have a surprising superpower: They can push away nano-sized molecules that happen to approach them. A team including scientists at the National Institute of Standards and Technology (NIST) has figured out why, by using artificial membranes that mimic the behavior of natural ones. Their discovery could make a difference in how we design the many drug treatments that target our cells.

The team's findings, which appear in the Journal of the American Chemical Society, confirm that the powerful electrical fields that cell membranes generate are largely responsible for repelling nanoscale particles from the surface of the cell.
This repulsion notably affects neutral, uncharged nanoparticles, in part because the smaller, charged molecules the electric field attracts crowd the membrane and push away the larger particles. Since many drug treatments are built around proteins and other nanoscale particles that target the membrane, the repulsion could play a role in the treatments' effectiveness.

The findings provide the first direct evidence that the electric fields are responsible for the repulsion.

This repulsion, along with the related crowding that the smaller molecules exert, is likely to play a significant role in how molecules with a weak charge interact with biological membranes and other charged surfaces.

This has implications for drug design and delivery, and for the behavior of particles in crowded environments at the nanometer scale.

Part 1

Membranes form boundaries in nearly all kinds of cells. Not only does a cell have an outer membrane that contains and protects the interior, but often there are other membranes inside, forming parts of organelles such as mitochondria and the Golgi apparatus. Understanding membranes is important to medical science, not least because proteins lodged in the cell membrane are frequent drug targets. Some membrane proteins are like gates that regulate what gets into and out of the cell.

The region near these membranes can be a busy place. Thousands of types of different molecules crowd each other and the cell membrane—and as anyone who has tried to push through a crowd knows, it can be tough going. Smaller molecules such as salts move with relative ease because they can fit into tighter spots, but larger molecules, such as proteins, are limited in their movements.

This sort of molecular crowding has become a very active scientific research topic, because it plays a real-world role in how the cell functions. How a cell behaves depends on the delicate interplay of the ingredients in this cellular "soup." Now, it appears that the cell membrane might have an effect too, sorting molecules near itself by size and charge.

How does crowding affect the cell and its behavior? How, for example, do molecules in this soup get sorted inside the cell, making some of them available for biological functions, but not others? The effect of the membrane could make a difference.

Marcel Aguilella-Arzo et al, Charged Biological Membranes Repel Large Neutral Molecules by Surface Dielectrophoresis and Counterion Pressure, Journal of the American Chemical Society (2024). DOI: 10.1021/jacs.3c12348. pubs.acs.org/doi/full/10.1021/jacs.3c12348

Scientists announce breakthrough in hypersonic heat shield

In a giant leap for future hypersonic flight,  scientists have turned to multi-scale technology to develop a revolutionary new material that has achieved record high marks in tests for vital strength and thermal insulation properties.

The scientists say their porous ceramic creation opens the door to wider exploration in the fields of aerospace, chemical engineering and energy transfer and production.

For the first time, it is reported a multi-scale structure design and fast fabrication of … high-entropy ceramics via an ultrafast high-temperature synthesis technique that can lead to exceptional mechanical load-bearing capability and high thermal insulation performance," the researchers said in a paper published Jan. 2 in the journal Advanced Materials.

Scientists have long faced challenges in developing strong, lightweight materials boasting low-thermal conductivity that are critical, especially for hypersonic travel. Ceramic materials offer promise because they exhibit low thermal conductivity, high melting points and corrosion resistance, and they are also non-combustible.
But exploration projects at great depths below the Earth's surface as well as in outer space encounter extremely high temperatures and pressure. Traditional ceramic materials are insufficient in those instances.

Lightweight, porous materials offered low thermal transfer but that desirable property often came with a tradeoff—greater fragility.

In their report, "Ultrastrong and High Thermal Insulating Porous High-Entropy Ceramics up to 2000 °C," researchers stated, "It is imperative to find ways to simultaneously improve the mechanical strength and thermal insulation capacity of porous ceramics."
Part 1

So they turned to the concept of high-entropy design to come up with a porous ceramic material that achieved a good balance between strength and heat resistance without the usual downsides.

High-entropy design focuses on the use of equal measures of multiple elements that can be used to create stronger, more heat-resistant and more stable components.

The researchers developed a material that achieved the demanding insulation and weight criteria for aerospace flight. Their new ceramic creation, which goes by the unassuming name 9PHEB—9-cation porous high-entropy diboride—provides "exceptional thermal stability" and "ultrahigh compressive strength," the researchers said.

"High-quality interfaces, characterized by strong bonding without defects or amorphous phases, can promote the rapid force transfer along the building block and to many other ones through connections upon loading, leading to a significant enhancement of mechanical strength," the report said.

With modification, CAR T cells can attack senescent cells, leading to slower aging in mice

Researchers have discovered that T cells can be reprogrammed to fight aging, so to speak. Given the right set of genetic modifications, these white blood cells can attack another group of cells known as senescent cells. These cells are thought to be responsible for many of the diseases we grapple with later in life.

Senescent cells are those that stop replicating. As we age, they build up in our bodies, resulting in harmful inflammation. While several drugs currently exist that can eliminate these cells, many must be taken repeatedly over time.
As an alternative, scientists turned to a "living" drug called CAR (chimeric antigen receptor) T cells. They discovered CAR T cells could be manipulated to eliminate senescent cells in mice. As a result, the mice ended up living healthier lives. They had lower body weight, improved metabolism and glucose tolerance, and increased physical activity. All benefits came without any tissue damage or toxicity.
If we give it to aged mice, they rejuvenate. If we give it to young mice, they age slower. No other therapy right now can do this.
Perhaps the greatest power of CAR T cells is their longevity. The team found that just one dose at a young age can have lifelong effects. That single treatment can protect against conditions that commonly occur later in life, like obesity and diabetes.
T cells have the ability to develop memory and persist in your body for really long periods, which is very different from a chemical drug. With CAR T cells, you have the potential of getting this one treatment, and then that's it. For chronic pathologies, that's a huge advantage. Think about patients who need treatment multiple times per day versus you get an infusion, and then you're good to go for multiple years.
CAR T cells have been used to treat a variety of blood cancers, receiving FDA approval for this purpose in 2017. But this team is one of the first scientists to show that CAR T cells' medical potential goes even further than cancer.

Nature Aging (2024). DOI: 10.1038/s43587-023-00560-5

Co-stimulatory signaling domains have been added to newer generations of CAR T cells to improve their ability to produce more T cells after infusion and survive longer in the circulation.

Researchers observe tiny pseudoscorpion riding on a scorpion

Researchers recently  documented the first observation of phoresy involving a myrmecophile pseudo-scorpion on a myrmecophile scorpion.

Phoresy, a well-established phenomenon among pseudoscorpions, involves their attachment to hosts for dispersal into new environments. Documented instances of phoresy include pseudoscorpions attaching themselves to various hosts, ranging from mammals and birds to different insect orders and even other arachnids.

The study focused on pseudoscorpions belonging to an endemic Withiidae species, Nannowithius wahrmani, observed clinging onto the endemic scorpion species Birulatus israelensis in Israel. The research paper, titled "Hitching a ride on a scorpion: the first record of phoresy of a myrmecophile pseudoscorpion on a myrmecophile scorpion," is published in Arachnologische Mitteilungen: Arachnology Letters.

Sharon Warburg et al, Hitching a ride on a scorpion: the first record of phoresy of a myrmecophile pseudoscorpion on a myrmecophile scorpion, Arachnologische Mitteilungen: Arachnology Letters (2024). DOI: 10.30963/aramit6605