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Comment by Dr. Krishna Kumari Challa on June 25, 2025 at 9:02am

Tomatoes in the Galápagos are quietly de-evolving

On the younger, black-rock islands of the Galápagos archipelago, wild-growing tomatoes are doing something peculiar. They're shedding millions of years of evolution, reverting to a more primitive genetic state that resurrects ancient chemical defenses.

These tomatoes, which descended from South American ancestors likely brought over by birds, have quietly started making a toxic molecular cocktail that hasn't been seen in millions of years, one that resembles compounds found in eggplant, not the modern tomato.

In a study published recently in Nature Communications, scientists at the University of California, Riverside, describe this unexpected development as a possible case of "reverse evolution," a term that tends to be controversial among evolutionary biologists.

That's because evolution isn't supposed to have a rewind button. It's generally viewed as a one-way march toward adaptation, not a circular path back to traits once lost. While organisms sometimes re-acquire features similar to those of their ancestors, doing so through the exact same genetic pathways is rare and difficult to prove.

However, reversal is what these tomato plants appear to be doing.

The key players in this chemical reversal are alkaloids. Tomatoes, potatoes, eggplants, and other nightshades all make these bitter molecules that act like built-in pesticides, deterring insect predators, fungi, and grazing animals.

While the Galápagos are famous as a place where animals have few predators, the same is not necessarily true for plants. Thus, the need to produce the alkaloids.

What makes these Galápagos tomatoes interesting isn't just that they make alkaloids, but that they're making the wrong ones, or at least, ones that haven't been seen in tomatoes since their early evolutionary days.

Part 1

Comment by Dr. Krishna Kumari Challa on June 24, 2025 at 11:30am

Recycled plastics can affect hormone systems and metabolism, study shows

A single pellet of recycled plastic can contain over 80 different chemicals. A new study by researchers shows that recycled polyethylene plastic can leach chemicals into water, causing impacts on the hormone systems and lipid metabolism of zebrafish larvae.

The work is published in the Journal of Hazardous Materials.

The plastic pollution crisis has reached global levels, threatening both planetary and human health, and recycling is proposed as one of the solutions to the plastics pollution crisis. However, as plastics contain thousands of chemical additives and other substances that can be toxic, and these are almost never declared, hazardous chemicals can indiscriminately end up in recycled products.

In a new study, researchers bought plastic pellets recycled from polyethylene plastic from different parts of the world and let the pellets soak in water for 48 hours. After which, zebrafish larvae were exposed to the water for five days. The experimental results show increases in gene expression relating to lipid metabolism, adipogenesis, and endocrine regulation in the larvae.

These short leaching times and exposure times are yet another indicator of the risks that chemicals in plastics pose to living organisms. The impacts that we measured show that these exposures have the potential to change the physiology and health of the fish.

Previous research has shown similar effects to humans, including threats to reproductive health and obesity, from exposure to toxic chemicals in plastics. Some chemicals used as additives in plastics and substances that contaminate plastics are known to disturb hormones, with potential impacts on fertility, child development, links to certain cancers, and metabolic disorders including obesity and diabetes.

Azora König Kardgar et al, Effects of leachates from black recycled polyethylene plastics on mRNA expression of genes involved in adipogenesis and endocrine pathways in zebrafish embryos, Journal of Hazardous Materials (2025). DOI: 10.1016/j.jhazmat.2025.138946

Comment by Dr. Krishna Kumari Challa on June 24, 2025 at 11:22am

Scientists find new blood type in Guadeloupe woman

A French woman from the Caribbean island of Guadeloupe has been identified as the only known carrier of a new blood type, dubbed "Gwada negative," France's blood supply agency has announced.

The announcement was made 15 years after researchers received a blood sample from a patient who was undergoing routine tests ahead of surgery, the French Blood Establishment (EFS) said on Friday.

"The EFS has just discovered the 48th blood group system in the world!" the agency said in a statement on social network LinkedIn.

"This discovery was officially recognized in early June in Milan by the International Society of Blood Transfusion (ISBT)."

The scientific association had until now recognized 47 blood group systems.

Thierry Peyrard, a medical biologist at the EFS involved in the discovery, told AFP that a "very unusual" antibody was first found in the patient in 2011.

Scientists were finally able to unravel the mystery in 2019 thanks to "high-throughput DNA sequencing," which highlighted a genetic mutation

The patient, who was 54 at the time and lived in Paris, was undergoing routine tests before surgery when the unknown antibody was detected.

She is the only person in the world who is compatible with herself

The woman inherited the blood type from her father and mother, who each had the mutated gene.

Comment by Dr. Krishna Kumari Challa on June 24, 2025 at 10:57am

Antimicrobial resistance genes hitch rides on imported seafood

Colistin is a potent, last-resort antibiotic used only to treat people with dangerous, life-threatening bacterial infections that have developed resistance to other drugs. But it's not foolproof. Worldwide, resistance to colistin is spreading, further diminishing treatment options and putting infected people at higher risk.

Researchers have identified a way that colistin  resistance genes are spreading: imported seafood.

In a new study, microbiologists  have reported the first isolation of colistin-resistance genes in bacteria found in imported shrimp and scallops, purchased from eight food markets around Atlanta, GA.

 Some countries do not have strict regulations for using antibiotics in food animal production, so imported food can be a vehicle for transmission of resistance,

The researchers presented the findings in Los Angeles at ASM Microbe 2025, the annual meeting of the American Society for Microbiology. An accompanying paper will be published in the journal mSphere.

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Comment by Dr. Krishna Kumari Challa on June 24, 2025 at 10:13am

Some 90% of the product made from reacting terephthalic acid with genetically reprogrammed E. coli was paracetamol.

Experts say this new approach demonstrates how traditional chemistry can work with engineering biology to create living microbial factories capable of producing sustainable chemicals while also reducing waste, greenhouse gas emissions and reliance on fossil fuels.

Nick W. Johnson et al, A biocompatible Lossen rearrangement in Escherichia coli, Nature Chemistry (2025). DOI: 10.1038/s41557-025-01845-5

Part 2

Comment by Dr. Krishna Kumari Challa on June 24, 2025 at 10:12am

Upcycling plastic into painkillers: Microbes transform everyday waste into acetaminophen

Traditionally, paracetamol (also known as acetaminophen) is made from fossil fuel-derived chemicals. Specifically, it's often synthesized from phenol, which is a derivative of crude oil. However, there are also research efforts focused on producing paracetamol from renewable sources like trees and even plastic waste. 

Paracetamol  production could be revolutionized by the discovery that a common bacterium can turn everyday plastic waste into the painkiller. The new method leaves virtually no carbon emissions and is more sustainable than the current production of the medicine, researchers say.

Paracetamol is traditionally made from dwindling supplies of fossil fuels including crude oil. Thousands of tons of fossil fuels are used annually to power the factories that produce the painkiller, alongside other medicines and chemicals—making a significant contribution to climate change, experts say.

The breakthrough addresses the urgent need to recycle a widely used plastic known as polyethylene terephthalate (PET), which ultimately ends up in landfill or polluting oceans. The strong, lightweight plastic is used for water bottles and food packaging, and creates more than 350 million tons of waste annually, causing serious environmental damage worldwide.

PET recycling is possible, but existing processes create products that continue to contribute to plastic pollution worldwide, researchers say.

Published in Nature Chemistry, a team of scientists from the University of Edinburgh's Wallace Lab used genetically reprogrammed E. coli, a harmless bacterium, to transform a molecule derived from PET known as terephthalic acid into the active ingredient of paracetamol.

Researchers used a fermentation process, similar to the one used in brewing beer, to accelerate the conversion from industrial PET waste into paracetamol in less than 24 hours.

The new technique was carried out at room temperature and created virtually no carbon emissions, proving that paracetamol can be produced sustainably. Further development is needed before it can be produced at commercial levels, the research team says.

Part 1

Comment by Dr. Krishna Kumari Challa on June 24, 2025 at 10:02am

Earth's satellites at risk if asteroid smashes into moon

If a huge asteroid smashes into the moon in 2032, the gigantic explosion would send debris streaming toward Earth that would threaten satellites and create a spectacular meteor shower, according to researchers.

It was given the highest chance—3.1%—of hitting our home planet that scientists have ever measured for such a giant space rock.

Subsequent observations from telescopes definitively ruled out a direct hit on Earth.

However, the odds that it will crash into the moon have risen to 4.3%, according to data from the James Webb Space Telescope in May.

A new preprint study, which has not been peer-reviewed, is the first to estimate how such a collision could affect Earth.

It would be the largest asteroid to hit the moon in around 5,000 years. The impact would be comparable to a large nuclear explosion in terms of the amount of energy released.

Up to 100 million kilograms (220 million pounds) of material would shoot out from the moon's surface, according to a series of simulations run by the researchers.

If the asteroid hit the side of the moon facing Earth—which is roughly a 50% chance—up to 10% of this debris could be pulled in by Earth's gravity over the following days, they said.

 These meteors could be capable of destroying some satellites—and there are expected to be a lot more of those orbiting the planet by 2032.

A centimeter-sized rock traveling at tens of thousands of meters per second is a lot like a bullet.

In the days after the impact, there could be more than 1,000 times the normal number of meteors threatening Earth's satellites.

Meanwhile, those of us on the ground would be treated to a "spectacular" meteor shower lighting up the night sky, the study said.

But the current odds of a direct hit on the near side of the moon remain at just two percent

The asteroid is not expected to be visible again until 2028, so the world will have to wait to find out more.

If a direct hit is eventually found to be likely, humanity probably has enough time to plan a mission to spare the moon.

The preprint study, which was published on the arXiv database last week, has been submitted to the Astrophysical Journal Letters.

 Paul Wiegert et al, The Potential Danger to Satellites due to Ejecta from a 2032 Lunar Impact by Asteroid 2024 YR4, arXiv (2025). DOI: 10.48550/arxiv.2506.11217

Comment by Dr. Krishna Kumari Challa on June 24, 2025 at 8:59am

While thousands of RiPPs have been identified in bacteria, only a handful have been found in fungi. In part, this is because past researchers misidentified fungal RiPPs as non-ribosomal peptides and had little understanding of how fungi created the molecules.

The synthesis of these compounds is complicated. But that's also what gives them this remarkable bioactivity.
To find more fungal RiPPs, the researchers first scanned a dozen strains of Aspergillus, which previous research suggested might contain more of the chemicals.

By comparing chemicals produced by these strains with known RiPP building blocks, the researchers identified A. flavus as a promising candidate for further study.

Genetic analysis pointed to a particular protein in A. flavus as a source of fungal RiPPs. When the researchers turned the genes that create that protein off, the chemical markers indicating the presence of RiPPs also disappeared.

This novel approach—combining metabolic and genetic information—not only pinpointed the source of fungal RiPPs in A. flavus, but could be used to find more fungal RiPPs in the future.After purifying four different RiPPs, the researchers found the molecules shared a unique structure of interlocking rings. The researchers named these molecules, which have never been previously described, after the fungus in which they were found: asperigimycins.

Even with no modification, when mixed with human cancer cells, asperigimycins demonstrated medical potential: two of the four variants had potent effects against leukemia cells.
Another variant, to which the researchers added a lipid, or fatty molecule, that is also found in the royal jelly that nourishes developing bees, performed as well as cytarabine and daunorubicin, two FDA-approved drugs that have been used for decades to treat leukemia.
Through further experimentation, the researchers found that asperigimycins likely disrupt the process of cell division. Cancer cells divide uncontrollably. These compounds block the formation of microtubules, which are essential for cell division.
Notably, the compounds had little to no effect on breast, liver or lung cancer cells—or a range of bacteria and fungi—suggesting that asperigimycins' disruptive effects are specific to certain types of cells, a critical feature for any future medication.
In addition to demonstrating the medical potential of asperigimycins, the researchers identified similar clusters of genes in other fungi, suggesting that more fungal RiPPS remain to be discovered.

 A class of benzofuranoindoline-bearing heptacyclic fungal RiPPs with anticancer activities, Nature Chemical Biology (2025). DOI: 10.1038/s41589-025-01946-9

Part 2

Comment by Dr. Krishna Kumari Challa on June 24, 2025 at 8:55am

Researchers turn toxic ancient tomb fungus into anti-cancer drug

Researchers have turned a deadly fungus into a potent cancer-fighting compound. After isolating a new class of molecules from Aspergillus flavus, a toxic crop fungus linked to deaths in the excavations of ancient tombs, the researchers modified the chemicals and tested them against leukemia cells. The result? A promising cancer-killing compound that rivals FDA-approved drugs and opens up new frontiers in the discovery of more fungal medicines.

Aspergillus flavus, named for its yellow spores, has long been a microbial villain. After archaeologists opened King Tutankhamun's tomb in the 1920s, a series of untimely deaths among the excavation team fueled rumors of a pharaoh's curse. Decades later, doctors theorized that fungal spores,

 dormant for millennia, could have played a role.

In the 1970s, a dozen scientists entered the tomb of Casimir IV in Poland. Within weeks, 10 of them died. Later investigations revealed the tomb contained A. flavus, whose toxins can lead to lung infections, especially in people with compromised immune systems.

Now, that same fungus is the unlikely source of a promising new cancer therapy.

The therapy in question is a class of ribosomally synthesized and post-translationally modified peptides, or RiPPs, pronounced like the "rip" in a piece of fabric. The name refers to how the compound is produced—by the ribosome, a tiny cellular structure that makes proteins—and the fact that it is modified later, in this case, to enhance its cancer-killing properties.

Part1

Comment by Dr. Krishna Kumari Challa on June 23, 2025 at 11:15am

Using ChatGPT to write essays may be eroding critical thinking skills

A team of neurologists and AI specialists at MIT's Media Lab has led a study looking into the brain impacts of large language model (LLM) use among people who engage with them for study or work. They report evidence that the use of LLMs may lead to an erosion of critical thinking skills. In their study, posted on the arXiv preprint server, the researchers asked groups of volunteers to write essays while connected to EEG monitors.

Researchers recruited 54 volunteers. The initial group was then split into three small groups, all of whom were asked to write a 20-minute esay on the topic of philanthropy—one group was asked to use ChatGPT for help, the second was asked to use Google Search, and the third "Brain-only" group was given no tools or resources at all. The participants remained in these same groups for three writing sessions.

Each of the volunteers was fitted with an EEG device to monitor brain activity, such as cognitive engagement and mental workload, while they wrote. The researchers also performed natural language processing analysis and interviewed participants after each session. Essays were scored by human teachers as well as an AI agent.

For these first three sessions, the EEG analysis showed clear differences in brain connectivity between the groups. The Brain-only group showed the strongest and most widespread brain network activity, the search engine group showed intermediate levels of engagement, and the ChatGPT group showed the weakest overall brain connectivity.

Out of the 54 volunteers, 18 also returned months later to complete a fourth session. Those who had used ChatGPT now went the Brain-only route, and vice versa. In this session, those who had originally used ChatGPT in the first three sessions showed weaker neural connectivity, while those from the previous Brain-only group demonstrated higher memory recall.

Overall, the interviews also revealed that volunteers who used the LLM felt less ownership over their essays compared to the other groups. ChatGPT users also struggled to recall or quote from their own essays shortly after writing them. Across all measures—brain activity, language analysis, and essay scoring—participants who relied on ChatGPT performed worse than the Brain-only group.

These findings highlight the potential educational impact of relying on LLMs for writing tasks. While they can provide immediate benefits, they run the risk of reduced learning outcomes over time and frequent use may hinder the development of critical thinking skills.

Nataliya Kosmyna et al, Your Brain on ChatGPT: Accumulation of Cognitive Debt when Using an AI Assistant for Essay Writing Task, arXiv (2025). DOI: 10.48550/arxiv.2506.08872

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