Comment

Comment by Dr. Krishna Kumari Challa on Wednesday

DNA floating in the air can track wildlife, viruses—even drugs

The level of information that's available in environmental DNA is such that we're only starting to consider what the potential applications can be, from humans, to wildlife to other species that have implications for human health.

Researchers have developed new methods for deciphering environmental DNA, also known as eDNA, to study sea turtle genetics. They've expanded the tools to study every species—including humans—from DNA captured in environmental samples like water, soil and sand.

But these errant strands of DNA do not just settle into muddy soil or flow along rivers. The air itself is infused with genetic material. A simple air filter running for hours, days or weeks can pick up signs of nearly every species that grows or wanders nearby.

That means you can study species without directly having to disturb them, without ever having to see them. It opens up huge possibilities to study all the species in an area simultaneously, from microbes and viruses all the way up to vertebrates like bobcats and humans, and everything in between.

As a proof of concept, the researchers showed that they could pick up signs of hundreds of different human pathogens from the  air, including viruses and bacteria. Such surveillance could help scientists track emerging diseases. The same method can track common allergens, like peanut or pollen, more precisely than is currently possible, the scientists discovered.

With little more than an air filter, scientists could track endangered species and identify where they came from, all without having to lay eyes on skittish animals or root around forest floors for scat samples. When trying to save and conserve wildlife, knowing where an animal originates from can be as important as knowing where it currently is.

This powerful analysis was paired with impressive speed and efficiency. The team demonstrated that a single researcher could process DNA for every species in as little as a day using compact, affordable equipment, and software hosted in the cloud. That quick turnaround is orders of magnitude faster than would have been possible just a few years ago and opens up advanced environmental studies to more scientists around the world.

Shotgun sequencing of airborne eDNA achieves rapid assessment of whole biomes, population genetics and genomic variation, Nature Ecology & Evolution (2025). DOI: 10.1038/s41559-025-02711-w

Comment by Dr. Krishna Kumari Challa on Wednesday

Scientists find new markers to identify species from fragments of fossilized bone

What happened to all the megafauna? From moas to mammoths, many large animals went extinct between 50 and 10,000 years ago. Learning why could provide crucial evidence about prehistoric ecosystems and help us understand future potential extinctions. But surviving fossils are often too fragmented to determine the original species, and DNA is not always recoverable, especially in hot or damp environments.

Now scientists have isolated collagen peptide markers which allow them to identify three key megafauna that were once present across Australia: a hippo-sized wombat, a giant kangaroo, and a marsupial with enormous claws.

Analyzing the peptides—short chains of amino acids—found in samples of collagen allows scientists to distinguish between different genera of animals, and sometimes between different species. Because collagen preserves better than DNA, this method can be applied successfully in tropical and sub-tropical environments where DNA is unlikely to survive.

Proteins generally preserve better over longer timescales and in harsh environments than DNA does. This means that in the context of megafauna extinctions, proteins may still be preserved where DNA is not.

The scientists ruled out any contaminants and compared the peptide markers they found to reference markers. The collagen in all three samples was well-preserved enough for the team to identify suitable peptide markers for all three species.

Using these markers, the team were able to differentiate Protemnodon from five living genera and one extinct genus of kangaroos. They were also able to distinguish Zygomaturus and Palorchestes from other living and extinct large marsupials, but they couldn't differentiate the two species from each other.

This is not unusual with ZooMS, since changes in collagen accumulate extremely slowly, over millions of years of evolution. Unless further research allows for more specificity, these markers are best used to identify bones at the genus level rather than the species.

However, the ability to tell apart genera from more temperate regions of Sahul does present an opportunity to try to identify bones found in more tropical areas, where closely related species—which are likely to have similar or even the same peptide markers—would have lived. DNA rarely preserves over time in these regions.

By using the newly developed collagen peptide markers, we can begin identifying a larger number of megafauna remains.

 Carli Peters et al, Collagen peptide markers for three extinct Australian megafauna species, Frontiers in Mammal Science (2025). DOI: 10.3389/fmamm.2025.1564287

Comment by Dr. Krishna Kumari Challa on Wednesday

Protein that helps green bush crickets mimic green foliage

A green bush cricket (Tettigonia cantans) can easily be mistaken for a plant appendage from a distance. Its leafy green hue allows it to blend seamlessly into its surroundings, camouflaging itself in meadows, marshes, and fields, the habitats it calls home. What makes the bush cricket green? 

A recent study discovered that the secret to this camouflaging superpower comes from a water-soluble protein called dibilinoxanthinin (DBXN), which binds two distinct pigments—a blue bilin and a yellow lutein—to mimic the color of green foliage closely.

With the help of the genetic sequence of protein and cloning, the researchers found that the protein was a highly fragmented form of vitellogenin, a protein family essential for embryonic development.

Researchers note that DBXN-like proteins were found in other green insects and even in a green spider, hinting at the convergent evolution of this camouflage mechanism.

Nikita A. Egorkin et al, A green dichromophoric protein enabling foliage mimicry in arthropods, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2502567122

Comment by Dr. Krishna Kumari Challa on Tuesday

The chemistry of interstellar space

Many people imagine the space between the stars as an empty, cold infinity. In reality, it is teeming with extraordinary molecules: More than 300 different types have already been discovered.

The conditions in space are completely different from those here on Earth. It is very cold, around -240°C, and the pressure is very low. There are far fewer collisions between molecules than on Earth: here, there are a billion collisions per second, while in space there is one every 10 days.

This means that certain molecules that occur in space cannot survive here on Earth. There are too many other molecules here that they would collide with immediately, causing them to ignite in the air or form new molecules. But how do you study those molecules?

At the HFML-FELIX laser and magnet lab, they have an enormous refrigerator that can cool down to -270°C and in which you can reduce the pressure. This creates conditions similar to those in space.  Then they would send a powerful infrared laser through the molecule to see how it would react.

Some researchers did this with the charged molecules C₂H⁺ and HC₂H⁺, which are thought to occur in space. We don't have these molecules on Earth because they react immediately with other molecules here. But we do have laser gas, which is used for welding. That's C₂H₂ and is very similar to HC₂H⁺ and C₂H⁺.

Welding gas is highly flammable and reacts immediately with air during welding. But if you take that welding gas, put it in a machine and fire a lot of electrons at it, it breaks down and you can extract HC₂H⁺ and C₂H^+.

By then firing an infrared laser at these charged molecules, researchers were able to obtain a kind of "fingerprint" of these molecules. To do this, they had to set up entirely new experimental methods and develop advanced theoretical models to understand the data. Once you have such a fingerprint and understand it, you can see if we can find it in the data collected by telescopes.

The method used by them has already helped find another of these exotic ions: CH₃⁺, which is methane (CH₄) with one less H. This molecule was observed in the Orion Nebula with the James Webb Space Telescope, in an area where stars are born. But we expect this molecule, and the others they investigated  to occur in many more places in space.

If we know exactly what the chemistry of space looks like, we can deduce how stars and planets are formed and how far a nebula is in its life cycle. Ultimately, it could also tell us something about how life on Earth originated and whether life can arise on other planets.

Source: Radboud University

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Comment by Dr. Krishna Kumari Challa on Tuesday

Forests aren't coming back after gold mining in the Amazon

Forests in the Peruvian Amazon aren't growing back after gold mining—not just because the soil is damaged by toxic metals, but because the land has been depleted of its water. A common mining method known as suction mining reshapes the terrain in ways that drain moisture and trap heat, creating harsh conditions where even replanted seedlings can't survive.

The findings, published in Communications Earth & Environment, revealed why reforestation efforts in the region have struggled. The mining process dries out the land, making it inhospitable for new trees. It's like trying to grow a tree in an oven!

To compare conditions, researchers installed sensors in various locations—sandy and clay soils, pond edges and undisturbed forests—and found that deforested sites were consistently hotter and drier. On exposed sand piles, surface temperatures reached as high as 145 F (60°C).

Drone-mounted thermal cameras showed how barren ground baked under the sun while nearby forested areas and pond edges stayed significantly cooler.

Abra Atwood et al, Landscape controls on water availability limit revegetation after artisanal gold mining in the Peruvian Amazon, Communications Earth & Environment (2025). Data on HydroShare Resources: DOI: 10.4211/hs.05a0490e971f491fa64c62cbde499a6a

Comment by Dr. Krishna Kumari Challa on Tuesday

Blood test detects multiple cancer types through cell-free DNA

Researchers  have validated a blood test that can detect a broad range of cancers with high accuracy using cell-free DNA. A multi-cancer early detection (MCED) test identified cancer with 87.4% sensitivity and 97.8% specificity in an independent validation cohort, and it correctly predicted the tissue of origin around 83% of the time.

Early detection remains a critical challenge in cancer care. Current screening tools contribute to late diagnoses and poor outcomes, especially in cancers lacking established screening protocols.

Cell-free DNA (cfDNA) circulating in the bloodstream, shed by tumors, has emerged as a promising target for noninvasive detection. Sensitivity for early-stage and less common cancers has remained low, yet the non-invasive nature of the tests makes them a compelling area for improvement.

In the study, "Early detection of multiple cancer types using multidimensional cell-free DNA fragmentomics," published in Nature Medicine, researchers designed a whole-genome sequencing–based blood test to detect cancer signals and predict the tissue of origin using machine learning models trained on cfDNA fragmentation patterns.

Researchers analyzed plasma-derived cell-free DNA using low-coverage whole-genome sequencing.

Nearly half of the cancers detected by the test were not identified through standard screening or physical examination. High sensitivity for cancers typically identified late in the disease course such as liver, ovarian, and pancreatic are extremely compelling and prediction of tissue origin adds further clinical relevance for early treatment.

Hua Bao et al, Early detection of multiple cancer types using multidimensional cell-free DNA fragmentomics, Nature Medicine (2025). DOI: 10.1038/s41591-025-03735-2

Comment by Dr. Krishna Kumari Challa on May 31, 2025 at 11:47am

The sleep switch: How one brain signal turns sleep on and off

Researchers showed that a single brain signal acts like a biological switch—both triggering sleep and ending it.

Their findings, published in the journal Current Biology, were made possible by studying a tiny roundworm, C. elegans, a powerful model organism in biology.

We know that falling asleep and waking up is controlled by a special set of brain cells, called sleep neurons. However, we don't know how exactly they control the downstream molecular pathways to make us fall asleep and wake up again until now.

Researchers turned to C. elegans to answer these questions. In contrast to humans, who have thousands of sleep neurons that control sleep, C. elegans needs just one neuron to do this job. This simplicity makes it a perfect model organism to study the principal molecular pathways controlling sleep.

This research sheds light on one of the fundamental questions in biology: how organisms regulate sleep and wakefulness. By understanding the fundamental molecular machinery behind sleep, researchers can better understand sleep disorders such as narcolepsy and insomnia that have a major impact on quality of life. The findings also add to the growing body of evidence that even simple model organisms can reveal fundamental mechanisms that govern life.

The team focused on a chemical messenger called FLP-11. When a sleep neuron activates, it releases FLP-11. Such chemical messengers work like molecular "notes" that are passed between brain cells to deliver different commands.

Through genetic screening, the researchers identified a key receptor, called DMSR-1, that FLP-11 binds to deliver its message. If this receptor was missing from the brain, researchers observed that the worms slept significantly less. DMSR-1 turned out to be present in different types of neurons. Depending on which neuron received the message, the results were dramatically different.

They discovered that FLP-11 activates DMSR-1 receptors in two completely different types of neurons.  They found the receptor present in neurons that promote wakefulness. When activated by FLP-11, the receptor turns off the wakefulness neurons. This, in turn, helps the worm fall asleep. On the other hand, the receptor is also present in the sleep neuron itself. Here, it also turns it off, which ultimately wakes the animal back up.

In other words, the same chemical that puts the worm to sleep also helps wake it up again, simply by targeting different cells in the brain. It is an efficient mechanism that controls the start of sleep while also keeping its duration in check.

Unlike humans, C. elegans have much shorter sleep phases that last only around 20 minutes. However, sleep is such a fundamental biological process that many molecules and mechanisms involved in sleep are shared across species. We don't yet know if the same sleep switch exists in humans, but it provides a promising clue in the search for mechanisms that control sleep in our species

Lorenzo Rossi et al, The neuropeptide FLP-11 induces and self-inhibits sleep through the receptor DMSR-1 in Caenorhabditis elegans, Current Biology (2025). DOI: 10.1016/j.cub.2025.03.039

Comment by Dr. Krishna Kumari Challa on May 31, 2025 at 11:30am

Harmful effects of gas cookers on health and the environment reviewed in report

Researchers put the magnitude of the problem into perspective by providing figures on the number of children with asthma and premature deaths associated with the use of gas cookers, and highlighted the need for measures and policies to reduce emissions from these appliances.

Environmental pollution is combined with fumes from gas cookers during normal use, and are believed to be the cause of  thousands of premature deaths.

They recommend electric cooking and induction cookers. 

 Assessment of the health impacts and costs associated with indoor nitrogen dioxide exposure related to gas cooking in the European Union and the United Kingdom, repositori.uji.es/items/156fbd … a4-9856-9415513d505f

Comment by Dr. Krishna Kumari Challa on May 30, 2025 at 10:38am

But when conflicts of interest take hold, even researchers cook up research results.

Will the companies that make these products stop using these 'chemicals'?

we are in the twilight zone now, neither here, not there. After knowing this, we have to take our own decisions now.

I am making my own ice creams now, without using any harmful chemicals.  I am making my own other things too. They might not be like the ones we buy outside. But  they are good for my health.  That is enough for me.

What about you? 

Sources: Microbiome, British medical journal, PLoS Medicine and medical express with inputs from Sci-Art Lab.

Part 4

Comment by Dr. Krishna Kumari Challa on May 30, 2025 at 10:28am

For a consumer, trying to steer clear of emulsifiers can be difficult. Without realizing it, people can consume a variety of emulsifiers from a variety of foods—and the same chemicals from multiple sources.

Polysorbate 80 alone was listed as an ingredient on the labels of 2,311 products!
Carrageenan was listed on 8,100 product labels; maltodextrin, 12,769; and xanthan gum, 17,153.
Some emulsifiers have multiple names, making them harder to recognize. Some names can apply to more than one emulsifier. Controllers find it difficult to identify them.
Carboxymethyl cellulose—not to be confused with methyl cellulose—is also known as carboxymethylcellulose and cellulose gum. Maltodextrin can be derived from substances such as cornstarch, rice starch, and wheat starch—but the FDA doesn't consider it synonymous with the term "modified food starch."

The naming practices can frustrate efforts to track the chemicals in food, to measure how much of the stuff people are taking in, and even to figure out precisely which chemicals a scientific study evaluated, researchers say.
And there is a hell lot of confusion everywhere!
The very term "emulsifier" is problematic. By strict definition, emulsifiers create an emulsion—a stable blend of liquids that would not otherwise mix, such as oil and water. However, the term is used broadly, encompassing chemicals such as maltodextrin that thicken, stabilize, or alter texture.

Emulsifiers can be found in foods marketed as natural or healthy as well as ones that look artificial. Some products contain multiple emulsifiers.

Research on emulsifiers has been building in recent years.

For instance, a study published in January this year by the Journal of Crohn's and Colitis concluded that a diet low in emulsifiers is an effective treatment for mild or moderate Crohn's disease. 

A study published in February 2024 in the journal PLOS Medicine found that higher intakes of carrageenan and mono- and diglycerides of fatty acids were associated with higher risks of cancer. The study observed 92,000 French adults for an average of 6.7 years.

A study published in September 2023 in The BMJ, formerly known as the British Medical Journal, found that intake of several types of emulsifiers was associated with the risk of cardiovascular disease. The study observed more than 95,000 French adults for a median of 7.4 years.

A series of earlier studies found that emulsifiers "can promote chronic intestinal inflammation in mice"; that two in particular, carboxymethyl cellulose and polysorbate 80, "profoundly impact intestinal microbiota in a manner that promotes gut inflammation and associated disease states"; and that, based on a laboratory study of human samples, "numerous, but not all, commonly used emulsifiers can directly alter gut microbiota in a manner expected to promote intestinal inflammation," as recounted in a 2021 paper in the journal Microbiome.

Part 3

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