Comment

Comment by Dr. Krishna Kumari Challa on Tuesday

'Rotten egg' gas could be the answer to treating nail infections, say scientists

Hydrogen sulfide, the volcanic gas that smells of rotten eggs, could be used in a new treatment for tricky nail infections that acts faster and with fewer side effects, according to scientists.

Hydrogen sulfide (H2S) demonstrates strong antimicrobial activity against a range of nail pathogens, including drug-resistant fungi, and penetrates the nail plate more effectively than current topical treatments. Laboratory results indicate it disrupts microbial energy production, causing irreversible damage. A topically applied H2S treatment may offer a faster, safer alternative for nail infections.

Nail infections are mostly caused by fungi and occasionally by bacteria. They are very common, affecting between 4 and 10% of the global population, rising to nearly half those aged 70 or over. These infections can lead to complications, particularly in vulnerable groups such as diabetics and the elderly, but are notoriously difficult to treat.
Current treatments include oral antifungals taken in pill form, and topical treatments applied directly to the nail. Oral antifungals take around 2–4 months to act and are reasonably effective, but they carry risks of side effects, especially in patients with other medical conditions.

Treatments applied directly to the nail are safer, but they often take much longer to work, sometimes taking even years to work, and they frequently relapse or fail. This is largely because it's very difficult to get the drug to penetrate through the nail to where the infection resides.

Even the most effective topical treatments have relatively low cure rates, so there is a clear need for new therapeutic approaches that are safe, effective, and capable of reaching microbes embedded deep within the nail.
Part 1

Comment by Dr. Krishna Kumari Challa on Tuesday

Tissue 'tipping points': How cells collectively switch from healthy to disease states

Cells convert mechanical forces into signals that influence physiological processes, such as exercise strengthening bones. A research team has discovered that biological tissues can also undergo dramatic phase transitions, or collective shifts where wound healing cells can switch from disordered, healthy states to highly coordinated disease states, like when water suddenly freezes into ice.

This discovery, published Oct. 3, 2025, in Proceedings of the National Academy of Sciences, reveals why fibrotic diseases often progress in switch-like jumps rather than gradually and points to new therapeutic strategies that target the physical properties of tissue rather than just cellular biochemistry.

The team used computational modeling to uncover the mechanical "tipping point" that determines whether cells can collectively coordinate to spread a disease called fibrosis, an excessive scarring that underlies failure of nearly any organ, and especially in diseases of the liver, lungs, kidneys and heart.

What they have shown is that this isn't a gradual process.

There's a sharp transition point. When cells are within a critical spacing that depends on the way their matrix deforms, they can 'talk' to each other mechanically through the matrix. Above it, they're effectively isolated, and below it they interact strongly with one another. This on-off switch behavior is what we see in fibrosis progression: periods of stability followed by rapid scarring.

Phase transitions are familiar in physics: Water freezes to ice at 0°C, and iron becomes ferromagnetic below 770°C. The new research demonstrates that living tissues show similar behavior. When cells are spaced far apart in a tissue, they act independently, but when cell density crosses a critical threshold—a few hundred micrometers apart—they begin communicating mechanically and acting in concert, dramatically compacting and stiffening the tissue.

The research shows why this phase transition occurs: Fibrous networks like collagen enable long-range mechanical communication in a way that uniform elastic materials cannot.

Collagen fibers can be recruited and aligned by cell forces, creating stiffened 'tension bands' that act as mechanical communication highways, transmitting signals over much longer distances.

The critical factor is what the researchers call the "critical stretch ratio," which is how much the collagen must be stretched before individual fibers align and stiffen. This property is determined by collagen crosslinking, which increases with aging and is influenced by factors like diet, advanced glycation end products, and metabolic diseases like diabetes.

 Xiangjun Peng et al, Fiber recruitment drives a phase transition of cell polarization at a critical cell spacing in matrix-mediated tissue remodeling, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2514995122

Comment by Dr. Krishna Kumari Challa on Tuesday

Bacteria reveal hidden powers of electricity transfer

Microbes are masters of survival, evolving ingenious strategies to capture energy from their surroundings. For decades, scientists thought that only a handful of bacteria used specialized molecular "circuits" to shuttle electrons outside their cells—a process known as extracellular electron transfer (EET). This mechanism is critical for cycling carbon, sulfur, nitrogen, and metals in nature, and it underpins applications ranging from wastewater treatment to bioenergy and bioelectronics materials.

Now researchers have discovered that this remarkable ability is far more versatile and widespread than previously imagined. The paper is published in The ISME Journal.

Working with Desulfuromonas acetexigens—a bacterium capable of generating high electrical currents—the team combined bioelectrochemistry, genomics, transcriptomics, and proteomics to map its electron transfer machinery. To their surprise, D. acetexigens simultaneously activated three distinct electron transfer pathways previously thought to have evolved separately in unrelated microbes: the metal-reducing (Mtr), outer-membrane cytochrome (Omc), and porin-cytochrome (Pcc) systems.

This is the first time researchers have seen a single organism express these phylogenetically distant pathways in parallel. It challenges the long-held view that these systems were exclusive to specific microbial groups.

The team also identified unusually large cytochromes, including one with a record-breaking 86 heme-binding motifs, which could enable exceptional electron transfer and storage capacity. Tests showed that the bacterium could channel electrons directly to electrodes and natural iron minerals, achieving current densities comparable to the model species Geobacter sulfurreducens.

By extending their analysis to publicly available genomes, the researchers identified more than 40 Desulfobacterota species carrying similar multipathway systems across diverse environments, from sediments and soils to wastewater and hydrothermal vents.

This reveals an unrecognized versatility in microbial respiration. Microbes with multiple electron transfer routes may gain a competitive advantage by tapping into a wider range of electron acceptors in nature.

The implications go well beyond ecology. Harnessing bacteria that can employ multiple electron transfer strategies could accelerate innovations in bioremediation, wastewater treatment, bioenergy production, and bioelectronics.

Dario R Shaw et al, Independently evolved extracellular electron transfer pathways in ecologically diverse Desulfobacterota, The ISME Journal (2025). DOI: 10.1093/ismejo/wraf097

Comment by Dr. Krishna Kumari Challa on Tuesday

Crop production in 155 countries relies on forests in other nations, moisture flows reveal

Forests play a crucial role in providing precipitation to agricultural areas, importantly supporting crop production and global trade activities. A recent study published in Nature Water emphasizes that to manage global food risks, it is essential to conserve forests located upwind of agricultural regions.

In recent decades, climate extremes have become more frequent and intense, leading to over half of the loss incidences in crop production worldwide. Concurrently, intense deforestation has diminished forests' ability to supply stable moisture to agricultural areas, resulting in reduced evaporation, less precipitation, and altered rainy seasons.

The moisture flows connect forests not only with the agricultural areas within the countries but also across the borders, according to a study by scholars.

To understand how forests contribute to global crop production and exports, the researchers compared moisture flows with crop production and export data.

This interdependence is well illustrated by the case of Brazil. In addition to providing moisture to its own agricultural areas, Brazilian forests influence crop production in Peru, Ecuador, Bolivia, Paraguay, Uruguay, and Argentina.

These countries account for 10% of global crop exports accounted in the study, including shipments to Europe, Asia, Africa, and Oceania. Thus, nations importing crops from South American countries are indirectly reliant on moisture from Brazilian forests.

The study reveals that overall, croplands in 155 countries depend on moisture from forests located in other countries for up to 40% of their annual precipitation.

Agnes Pranindita et al, Forests support global crop supply through atmospheric moisture transport, Nature Water (2025). DOI: 10.1038/s44221-025-00518-4

Comment by Dr. Krishna Kumari Challa on Tuesday

Bacteria borrow jumbo phages to spread their own defenses

A team of evolutionary biology researchers has discovered a new class of bacterial mobile genetic elements that use giant viruses—known as jumbo phages—to move between cells. The work, published in the Proceedings of the National Academy of Sciences, uncovers an unexpected twist in the long-running arms race between bacteria and their viruses.

In the study, a common bacterium was exposed to sterile filtrate from garden compost. The bacterium picked up several previously unknown DNA elements, each carrying genes that defend against phage infection. Remarkably, one of these elements, named I55, was found to hitch a ride on a jumbo phage, making it one of the first examples of a phage satellite exploiting such a large virus. The element not only spreads via the phage but also protects its bacterial host through a restriction–modification system—effectively allowing the bacterium to borrow viral machinery for its own benefit.

Yansong Zhao et al, Jumbo phage–mediated transduction of genomic islands, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2512465122

Comment by Dr. Krishna Kumari Challa on Tuesday

Urban settings showed larger estimated effects for PM2.5, sulfate, and ammonium compared with rural areas. Sex-stratified results indicated larger estimates for male children, with sulfate the only pollutant significantly associated among female children.

Neighborhood patterns suggested more pronounced estimated risks in lower-income and middle-income areas and in areas with higher proportions of racialized and newcomer populations.

Authors conclude that prenatal exposure to specific PM2.5 components, particularly sulfate and ammonium, was associated with autism risk, with sensitive periods in the second and third trimesters.

Postnatal ozone exposure in the first year of life was also associated with risk. Findings point to the potential importance of early-life environmental exposures.

Maxime Cloutier et al, Prenatal Exposure to Fine Particulate Matter Components and Autism Risk in Childhood, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2025.38882

Part 2

Comment by Dr. Krishna Kumari Challa on Tuesday

Prenatal exposure to specific fine particles linked to autism risk

A multi-institutional team  has found that prenatal air exposure to specific particulate matter components and early-life ozone is associated with autism spectrum disorder in  children.

Fine particulate matter has been linked to adverse health outcomes, with prenatal and early postnatal exposure associated with neurodevelopmental outcomes including autism spectrum disorder.

Most previous work has focused on fine particulate matter of airborne particles with a diameter of 2.5 micrometers or less (PM2.5), leaving uncertainty about variation in toxic effects among various chemical components and timing of exposure related to sensitive points in pregnancy. A large Southern California cohort study reported associations for several components, including sulfate, and a follow-up study also noted nitrate.

In the study, "Prenatal Exposure to Fine Particulate Matter Components and Autism Risk in Childhood," published in JAMA Network Open, researchers conducted a population-based retrospective cohort study to examine associations between prenatal and first-year-of-life exposure to specific PM_2.5 components, nitrogen dioxide, and ozone with autism diagnoses, and to identify potentially sensitive gestational windows.

Looking at birth through the first five years in Ontario, covering approximately 20 years, yielded 2,183,324 children after exclusions and 19,569 children who received an autism diagnosis.

Exposure assessment assigned prenatal concentrations by maternal postal code at delivery. Weekly nitrogen dioxide and ozone and biweekly PM2.5 mass and components were estimated from conception to age 36 weeks, with first-year exposures as annual postal code–level averages weighted by time at each address. Components included black carbon, dust, ammonium, nitrate, organic matter, sulfate, and sea salt. Models integrated satellite data, chemical transport modeling, land-use regression, and ground monitoring data.

Prenatal PM_2.5 mass was associated with increased risk when adjusted for first-year averages (HR 1.15), and window-specific signals were driven by sulfate during weeks 23–36 (HR 1.11) and ammonium during weeks 21–34 (HR 1.11), after which PM_2.5 mass was no longer associated with autism.

First-year ozone exposure was associated with autism risk with HR 1.09. Weekly models indicated significant windows for PM_2.5 during gestational weeks 14 to 32, sulfate during weeks 23 to 36, ammonium during weeks 21 to 34, and ozone during weeks 26 to 30, with reported window-specific HRs of 1.12 for PM_2.5, 1.11 for sulfate, 1.11 for ammonium, and 1.03 for ozone.

Black carbon, organic matter, dust, sea salt were not significant after adjustments, suggesting that specific chemical and not general PM_2.5 exposure associations.

Part 1

Comment by Dr. Krishna Kumari Challa on Sunday

Chimpanzees rationally revise their beliefs

New evidence? No problem. Chimps can weigh conflicting clues, just like humans

Study is first to suggest our closest relatives think about their own thoughts

 Chimpanzees rationally revise their beliefs on the basis of evidence. 

In a series of play-based experiments at a Ugandan chimp sanctuary, researchers watched as the apes assessed the quality of the evidence before them, altered their behavior based on what they saw, and even revised their beliefs in light of new information. The results, published recently in Science, suggest chimpanzees can use the evidence in front of them to make smart decisions—and strengthen the case that these great apes think about their own thoughts, with awareness of what they do and don’t know.

https://www.science.org/doi/10.1126/science.adq5229

Comment by Dr. Krishna Kumari Challa on Sunday

AI gets ‘brain rot’ from social media
Artificial intelligence (AI) chatbots trained on ‘brain rot’ content — vapid social media posts that are the equivalent of mental junk food — are worse at generating accurate information. Researchers found that chatbots given a diet of popular and sensationalist Twitter/X posts skipped steps in their reasoning process (or didn’t use reasoning at all), spat out wrong answers and demonstrated ‘dark traits’ such as psychopathy and increased levels of narcissism.

Nature 
 arXiv preprint (not peer reviewed)

Comment by Dr. Krishna Kumari Challa on Saturday

The question was: How can a cuckoo reliably pass on the right egg color? After all, a female might not know what her own egg looks like.
Presumably, a female cuckoo will return to a nest of the type in which she was raised. For the egg color to really match, however, it needs to be encoded in the bird's genes. As far back as the 1930s, the hypothesis was formulated that the responsible genes reside somewhere on the maternal lineage.

The current analyses now confirm that the base color of the eggs of the European cuckoo is inherited almost exclusively via the female sex chromosome—the W chromosome—and mitochondria. The patterning, by contrast, depends to a greater extent on autosomal genes, which come from both parents. In the Oriental cuckoos studied, whose eggs were all whitish-green and differed only in their patterning, the researchers found no inheritance via the maternal lineage.
Inheritance via the W chromosome ensures that daughters always lay eggs with the same base color as their mothers. For new adaptations, however, this type of inheritance is suboptimal, as the possibilities of genetic variation are limited and more strongly dependent on random mutations than in the case of DNA inherited from both parents.
The researchers observed that a gene which 's possibly involved in egg coloration evidently 'migrated' from the autosomes [the non-sex chromosomes inherited from both parents] to the W chromosome.
Matrilineal inheritance shapes how genetic variation is spread across a species. When traits matter for both males and females, adapting to different hosts can quickly drive populations apart—and eventually create new species. In the cuckoo, by contrast, females can freely mate with any male without losing their adaptation to their host. The flow of genetic information across the rest of the genome is preserved.
And that is precisely what the researchers observed: The huge cuckoo population throughout Eurasia is almost genetically identical within DNA regions inherited from both parents.
But this evolutionary advantage does not protect the cuckoo from the dangers of the present. In many regions of Europe, populations are significantly declining, because their habitats are disappearing. "Without intact habitats, this fascinating system risks vanishing on our doorstep," caution the researchers.

Justin Merondun et al, Genomic architecture of egg mimicry and its consequences for speciation in parasitic cuckoos, Science (2025). DOI: 10.1126/science.adt9355

Part 2

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