Comment

Comment by Dr. Krishna Kumari Challa on Friday

This durability makes iron biosignatures particularly attractive for planetary exploration. Unlike fragile organic molecules that degrade under radiation and harsh chemistry, mineralized iron structures can survive. Researchers have identified these biosignatures in environments ranging from hydrothermal vents on the ocean floor to terrestrial soils, from acidic mine drainage to neutral freshwater springs. Wherever liquid water contacts iron-bearing rocks, iron-metabolizing bacteria typically establish themselves.

Mars presents an obvious target. The planet's distinctive red color comes from oxidized iron in surface dust and rocks. Ancient Mars hosted liquid water, and spacecraft have documented iron-rich minerals throughout the geological record. If microbial life ever evolved on Mars, iron metabolism would have provided an accessible energy source. The minerals these hypothetical organisms produced could still exist, locked in ancient sediments awaiting discovery by rovers equipped with the right instruments.

The icy moons Europa and Enceladus offer different but equally compelling possibilities. Both harbor subsurface oceans beneath frozen shells. Europa's ocean likely contacts a rocky seafloor, where water and rock interactions would release dissolved iron. Enceladus actively vents ocean material through ice geysers at its south pole. Mission concepts propose sampling these plumes or landing near the vents, analyzing ejected particles for iron minerals that might betray biological origins.

The review emphasizes that recognizing biogenic iron minerals requires understanding how they form, what textures they create, and how they differ from abiotic iron precipitates. Mission planners must equip spacecraft with instruments capable of detecting not just iron minerals generally, but the specific morphological and chemical signatures that distinguish biology from geology.

The stakes are high. Finding iron biosignatures on another world wouldn't just confirm life exists elsewhere, it would reveal that the same fundamental chemistry supporting Earth's deep biosphere operates throughout the solar system.

Laura I. Tenelanda-Osorio et al, Terrestrial iron biosignatures and their potential in solar system exploration for astrobiology, Earth-Science Reviews (2025). DOI: 10.1016/j.earscirev.2025.105318

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Comment by Dr. Krishna Kumari Challa on Friday

The rust that could reveal alien life

Iron rusts. On Earth, this common chemical reaction often signals the presence of something far more interesting than just corroding metal—for example, living microorganisms that make their living by manipulating iron atoms. Now researchers argue these microbial rust makers could provide some of the most promising biosignatures for detecting life on Mars and the icy moons of the outer solar system.

Researchers now have compiled a comprehensive review of how iron metabolizing bacteria leave distinctive fingerprints in rocks and minerals, and why these signatures matter for astrobiology. The research, published in Earth-Science Reviews, bridges decades of terrestrial microbiology with the practical challenges of searching for life beyond Earth.

Iron ranks among the most abundant elements in the solar system, and Earth's microorganisms have evolved remarkably diverse ways to exploit it. Some bacteria oxidize ferrous iron to generate energy, essentially breathing iron the way humans breathe oxygen. Others reduce ferric iron, using it as the final electron acceptor in their metabolism. These processes don't happen in isolation. Iron metabolizing microbes link their element of choice to the carbon and nitrogen cycles, coupling iron transformations to carbon dioxide fixation, organic matter degradation, and even photosynthesis.

The byproducts of these microbial reactions create what researchers call biogenic iron oxyhydroxide minerals. These aren't subtle traces. Organisms that thrive in neutral pH environments and oxidize iron produce distinctive structures such as twisted stalks, tubular sheaths, and filamentous networks of iron minerals mixed with organic compounds. The minerals precipitate as the bacteria work, forming rusty deposits that can persist in the geological record for billions of years.

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Comment by Dr. Krishna Kumari Challa on Friday

The microrobots also contain the active ingredient they need to deliver. The researchers successfully loaded the microrobots with common drugs for a variety of applications—in this case, a thrombus-dissolving agent, an antibiotic or tumor medication.

These drugs were released by a high-frequency magnetic field that heats the magnetic nanoparticles, dissolving the gel shell and the microrobot.

The researchers used a two-step strategy to bring the microrobot close to its target: first, they injected the microrobot into the blood or cerebrospinal fluid via a catheter. They went on to use an electromagnetic navigation system to guide the magnetic microrobot to the target location.

The catheter's design is based on a commercially available model with an internal guidewire connected to a flexible polymer gripper. When pushed beyond the external guide, the polymer gripper opens and releases the microrobot.
To precisely steer the microrobots, the researchers developed a modular electromagnetic navigation system suitable for use in the operating theater.

 Fabian C. Landers et al, Clinically ready magnetic microrobots for targeted therapies, Science (2025). DOI: 10.1126/science.adx1708. www.science.org/doi/10.1126/science.adx1708

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Comment by Dr. Krishna Kumari Challa on Friday

Magnetic nanoparticles that successfully navigate complex blood vessels may be ready for clinical trials
Magnetic microrobots with iron oxide and tantalum nanoparticles can be precisely guided through complex blood vessels using modular electromagnetic navigation, delivering drugs directly to target sites such as thrombi. These microrobots achieve over 95% delivery accuracy in realistic vessel models and animal tests, supporting readiness for clinical trials and potential applications beyond vascular occlusions.

Every year, 12 million people worldwide suffer a stroke; many die or are permanently impaired. Currently, drugs are administered to dissolve the thrombus that blocks the blood vessel. These drugs spread throughout the entire body, meaning a high dose must be administered to ensure that the necessary amount reaches the thrombus. This can cause serious side effects, such as internal bleeding.

Since medicines are often only needed in specific areas of the body, medical research has long been searching for a way to use microrobots to deliver pharmaceuticals to where they need to be: in the case of a stroke, directly to the stroke-related thrombus.

Now, a team of researchers at ETH Zurich has made major breakthroughs on several levels. They have published their findings in Science.

The microrobot the researchers use comprises a proprietary spherical capsule made of a soluble gel shell that they can control with magnets and guide through the body to its destination. Iron oxide nanoparticles in the capsule provide the magnetic properties.

Because the vessels in the human brain are so small, there is a limit to how big the capsule can be. The technical challenge is to ensure that a capsule this small also has sufficient magnetic properties.

The microrobot also needs a contrast agent to enable doctors to track via X-ray how it is moving through the vessels. The researchers focused on tantalum nanoparticles, which are commonly used in medicine but are more challenging to control due to their greater density and weight.

Combining magnetic functionality, imaging visibility and precise control in a single microrobot required perfect synergy between materials science and robotics engineering, which has taken the researchers many years to successfully achieve.

They developed precision iron oxide nanoparticles that enable this delicate balancing act.

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Comment by Dr. Krishna Kumari Challa on Friday

Chinese team finds a fern that makes rare earth elements

Scientists have discovered a fern from South China that naturally forms tiny crystals containing rare earth elements (REEs). This breakthrough opens the door to a promising new way of "green mining" of these minerals called phytomining.

REEs are a group of 17 elements, all metals with similar properties that are essential for everything from wind turbines and electric car batteries to smartphones and medical scanners.

Extracting them is expensive and normally involves large-scale conventional mining operations that rely on harsh chemicals and cause significant pollution and land damage. That's why researchers are exploring cleaner, sustainable plant-based alternatives to collect REEs.

According to a paper published in the journal Environmental Science & Technology, the researchers studied the Blechnum orientale fern, which had been collected from REE-rich areas in South China. It was already known to be a hyperaccumulator, which is a plant that can grow in soil and water with high concentrations of metals and absorb them through its roots. But what they didn't know was the chemical form the REEs take when inside the plant. This knowledge is vital for designing the most efficient extraction process.

Using high-powered imaging technology and chemical analysis, the team discovered that the fern was forming nanoscale crystals of the REE-rich mineral monazite within its tissues, particularly in the cell walls and spaces between cells. Monazite is one of the main sources of rare earth elements in geological ore deposits worldwide.

The study authors also observed the crystal form, noting that it grows in a highly complex self-organizing pattern of tiny branches, likening it to a microscopic "chemical garden." This is the first time scientists have seen a living plant create a rare earth element crystal.

While we might not be going out to garden for REEs in the immediate future, the research is further proof that phytomining is feasible. The discovery, even with just one fern, strengthens the case that plants could one day provide a valuable, cheaper, and less destructive method for extracting much-needed rare earth elements.

 Liuqing He et al, Discovery and Implications of a Nanoscale Rare Earth Mineral in a Hyperaccumulator Plant, Environmental Science & Technology (2025). DOI: 10.1021/acs.est.5c09617

Comment by Dr. Krishna Kumari Challa on Friday

Our solar system is moving faster than expected

How fast and in which direction is our solar system moving through the universe? This seemingly simple question is one of the key tests of our cosmological understanding. A research team of astrophysicists has now found new answers, ones that challenge the established standard model of cosmology.

The study's findings have just been published in the journal Physical Review Letters.

Their analysis shows that the solar system is moving more than three times faster than current models predict. This result clearly contradicts expectations based on standard cosmology and forces us to reconsider our previous assumptions. 

To determine the motion of the solar system, the team analyzed the distribution of so-called radio galaxies, distant galaxies that emit particularly strong radio waves, a form of electromagnetic radiation with very long wavelengths similar to those used for radio signals. Because radio waves can penetrate dust and gas that obscure visible light, radio telescopes can observe galaxies invisible to optical instruments.

As the solar system moves through the universe, this motion produces a subtle "headwind": slightly more radio galaxies appear in the direction of travel. The difference is tiny and can only be detected with extremely sensitive measurements.

Using data from the LOFAR (Low Frequency Array) telescope, a Europe-wide radio telescope network, combined with data from two additional radio observatories, the researchers were able to make an especially precise count of such radio galaxies for the first time. They applied a new statistical method that accounts for the fact that many radio galaxies consist of multiple components. This improved analysis yielded larger but also more realistic measurement uncertainties.

Despite this, the combination of data from all three radio telescopes revealed a deviation exceeding five sigma, a statistically very strong signal considered in science as evidence for a significant result.

The measurement shows an anisotropy ("dipole") in the distribution of radio galaxies that is 3.7 times stronger than what the standard model of the universe predicts. This model describes the origin and evolution of the cosmos since the Big Bang and assumes a largely uniform distribution of matter.

If our solar system is indeed moving this fast, we need to question fundamental assumptions about the large-scale structure of the universe, say the cosmologists. 

Alternatively, the distribution of radio galaxies itself may be less uniform than we have thought. In either case, the current models are being put to the test.

The new results confirm earlier observations in which researchers studied quasars, the extremely bright centers of distant galaxies where supermassive black holes consume matter and emit enormous amounts of energy. The same unusual effect appeared in these infrared data, suggesting that it is not a measurement error but a genuine feature of the universe.

Lukas Böhme et al, Overdispersed Radio Source Counts and Excess Radio Dipole Detection, Physical Review Letters (2025). DOI: 10.1103/6z32-3zf4

Comment by Dr. Krishna Kumari Challa on Thursday

How much protein you really need

Most official guidelines recommend a bare minimum of close to one gram of protein per kilogram of body weight per day. But many scientists object to suggestions flying around social media that people need m.... Here’s what experts advise:

• Protein needs can vary from person to person and can change throughout a lifetime. “For older adults, 1.2 grams per kilogram is just giving them a little extra protection,” says nutrition and exercise researcher Nicholas Burd.
• Meeting your protein needs with plants rather than meat is better for your heart and the planet, but it might require a greater variety of foods (and maybe supplements).
• If you’re getting enough calories and eating a varied diet, you’re probably getting enough protein.
• For most people, unless you have kidney disease, too much protein won’t hurt you.

https://www.nature.com/articles/d41586-025-03632-1?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on Thursday

How Lung and Breast Cells Fight Cancer Differently

The study findings can help develop early-stage cancer prevention strategies.

Researchers have discovered why a specific mutation leads to tumorous growth in human lungs. The same mutation, however, fails to develop a tumor in human breasts, reducing the chances of a cancer.

They focused on the human epithelial tissues, the thin sheets of cells that line our vital organs. That’s because eighty percent of all human cancers begin in epithelial tissues. 

epithelial cells act as the body’s first barrier and are constantly exposed to stress, damage, and mutations. In fact, both the lung and the breast epithelial tissues display ‘epithelial defense against cancer’ — the epithelium’s natural act against tumorous cells. That’s why the group tested a specific cancerous mutation that occurs in both breast and lung epithelial tissues.

Researchers have long recognized that breast and lung epithelial tissues exhibit distinct differences. Breast epithelium is relatively stable and compact — the cells are tightly packed with stronger junctions. On the other hand, lung epithelium expands and relaxes with each breath, which is why its cells are more flexible, elongated, and loosely connected.

The group, through a combination of live imaging and computer models, has determined how these differences directly lead to the lung epithelium being more prone to growing tumors compared to the breast.

Once a cancerous mutation sets in the breast tissue, single mutant cells are pushed out, and groups of cells get stuck together. In lung tissue, the same mutant cells spread easily and make finger-like shapes.

The team found that the “tug-of-war” forces between normal and mutant cells decide whether cancerous cells are removed, trapped, or allowed to grow. Thus, cell mechanics help explain tissue-specific cancer risk. The surprise was how directly those mechanics determine whether mutant cells are restrained or allowed to spread.

A belt forms around the tumor in the breast epithelia, raises tension, jams the mutant cluster, and often forces out single mutants. Thus, this belt restrains the tumor.

In the lung epithelia, the cells are more elongated, motile, and weakly connected. So, no such belt forms, allowing the mutant cells to survive, grow longer, and spread into the tissue.

The group’s work demonstrates a pathway to resisting the growth of mutations into tumors, and eventually, into cancers. 

https://elifesciences.org/reviewed-preprints/106893v1

Comment by Dr. Krishna Kumari Challa on Thursday

The internal clock of immune cells: Is the immune system younger in the morning?

As the immune system ages, it reacts more slowly to pathogens, vaccines become less effective, and the risk of cancer increases. At the same time, the immune system follows a 24-hour rhythm, as the number and activity of many immune cells fluctuate throughout the day.

Researchers  have now investigated whether this daily rhythm influences the aging of the immune system and whether the immune system behaves "younger" or "older" at certain times of the day.

For the new study published in Frontiers in Aging, researchers took blood samples from participants in the morning, at noon, and in the evening. Using the so-called "IMMune Age indeX (IMMAX)," they determined each individual's immune age and analyzed how it changed throughout the day.

The IMMAX is a biomarker determined by the ratio of certain immune cells in the blood. As part of biological age, it correlates with actual chronological age.

Individual immune cells that are relevant for calculating the IMMAX fluctuate throughout the day. For example, in the morning, researchers observed an increased frequency of natural killer cells (NK cells)—key protective cells that defend the body against infections and cancer. In contrast, other immune cell types showed the opposite pattern.

The circadian rhythm regulates immune system activity. Hormones, body temperature, nerve signals, and messenger molecules tell immune cells when to move or become active. This leads to daily fluctuations in the number of immune cells in the blood. However, these fluctuations do not appear to influence immune age over the course of the day, as the researchers discovered. Despite measurable daily differences, the IMMAX remained largely stable, as individual immune cell types apparently balance each other out.

The IMMAX is a biomarker for immune age that is largely independent of the time of day. Nevertheless, slight differences were observed depending on a person's chronotype—that is, whether they are more active early in the day ("larks") or late in the day ("owls"). For early risers ("larks"), the IMMAX value decreased slightly from morning to noon. This suggests that the time of blood sampling in relation to waking up is important.
"When we wake up in the morning and become active, this apparently influences the movement of our immune cells and thus has a slight effect on the IMMAX value.

In large cohort studies, the timing of sampling is less critical, as fluctuations are balanced out.

Sina Trebing et al, Influence of circadian rhythm on the determination of the IMMune age indeX (IMMAX), Frontiers in Aging (2025). DOI: 10.3389/fragi.2025.1716985

Comment by Dr. Krishna Kumari Challa on Thursday

Indeed, a more diverse microbiome is generally correlated with increased sleep efficiency and total sleep time. Better sleep is also associated with a higher abundance of bacteria with health-promoting metabolic functions, like production of short-chain fatty acids (SCFAs), whereas conditions like insomnia are linked with lower abundances of these microbes. Whether insomnia causes these alterations, or vice versa, is still unclear—likely, they feed into one another.

Like many of the chemicals and processes powering our bodies, the composition of the microbiome naturally fluctuates throughout the day. These changes are linked to host circadian processes, and alterations in sleep (e.g., jet lag) can disrupt microbiota rhythms, resulting in important health implications.

"[What] we find in stress-related disorders, [and] in many mental health disorders in general, is that they're often associated with disordered sleep and dysregulation of sleep and circadian rhythms.
Researchers recently showed in animal models that daily fluctuations in stress pathways closely linked to sleep (e.g., cortisol levels) are modulated by the microbiome. 

They found  that there are circuits in the brain that are sensitive to microbial signals. Now, they  are seeking to identify the mechanisms that underlie those sensitivities.

https://asm.org/articles/2025/november/cant-sleep-your-microbiome-m...

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