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Comment by Dr. Krishna Kumari Challa on March 27, 2025 at 12:56pm

Tadpoles try to flee dangerous virus in their pond by growing much faster than normal, research shows

The world's amphibians are in trouble. Because of their sensitivity to climate change, habitat loss, and pollution, they may be the canary in the coal mine for the nascent anthropogenic mass extinction. Approximately 200 amphibian species have become extinct since the 1970s, and the International Union for the Conservation of Nature estimates that 34% of the 7,296 known remaining species are likewise at risk.

Another reason why amphibians are vulnerable is their susceptibility to disease. An emerging, potentially deadly disease of frogs and salamanders is ranavirus, a genus of at least seven species within the family Iridoviridae. Ranavirus can rapidly jump from host to host among fish, amphibians, and reptiles: a flexibility that can have catastrophic consequences if new host species haven't yet evolved any immunity.

But as a new study in Frontiers in Amphibian and Reptile Science has now shown, amphibians aren't entirely defenseless against ranavirus.

In response to ranavirus, wood frog tadpoles change their growth, development, and resource allocation. This may help tadpoles tolerate the energetic demands of infection or escape risky environments to avoid infection entirely.

Ranavirus has been implicated in 40% to 60% of amphibian die-offs in some parts of the world. Infected larvae stop feeding and become lethargic, while swimming abnormally and bleeding internally. An outbreak often leads to the death of all larvae in a pond, and there is evidence that outbreaks are becoming more frequent due to climate change.

The authors of the paper studied the growth and development of the wood frog Rana sylvatica in a forest. 

They compared three pond types: 35 which remained free from ranavirus over an entire season; seven which contained some infected tadpoles but saw little or no mortality; and five with an outbreak that killed off the entire cohort.

From mid-April to mid-July, the researchers regularly visited ponds to estimate the number of live and dead individuals. They collected up to 20 tadpoles from each and humanely euthanized them. In the laboratory, they determined the presence or absence of ranavirus in the liver of 1,583 of these with quantitative real-time PCR.

They also measured the total length of 4,299 tadpoles and determined their developmental stage—the so-called Gosner stage, which ranges from zero for embryos to 42 for tadpoles on the brink of metamorphosis.

Part 1

Comment by Dr. Krishna Kumari Challa on March 26, 2025 at 1:38pm

Brains might eat myelin during marathons

Brain scans of marathon runners suggest that myelin — a fatty substance that insulates the electrical signals transmitted by nerve cells — might also be a source of energy for the brain. After a race, runners’ levels of myelin are lower in areas involved in motor control and sensory and emotional processing than before they set off. The loss doesn’t seem to affect cognitive function, and levels bounced back after a couple of months. The experience might even be beneficial because it “exercises the brain’s metabolic machinery”.

https://www.nature.com/articles/s42255-025-01244-7?utm_source=Live+...

https://www.nature.com/articles/d41586-025-00864-z?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on March 26, 2025 at 11:09am

 New research suggests plants, fungi and even viruses use venom

A new study reveals plants, fungi, bacteria, protists, and even some viruses deploy venom-like mechanisms, similar to that of venomous snakes, scorpions and spiders.

The study is published in the journal Toxins.

The definition of venom is a biological toxin introduced into the internal milieu of another organism through a delivery mechanism such as a sting or bite that inflicts a wound.

 The new findings show that reliance on venom for solving problems like predation, defense, and competition is far more widespread than previously recognized.

Until now, our understanding of venom, venom delivery systems, and venomous organisms has been based entirely on animals, which represents only a tiny fraction of the organisms from which we could search for meaningful tools and cures.

According to the study, plants inject toxins into animals through spines, thorns, and stinging hairs, and some also co-exist with stinging ants by providing living spaces and food in exchange for protection. Even bacteria and viruses have evolved mechanisms, like secretion systems or contractile injection systems, to introduce toxins into their targets through host cells and wounds.

We've only scratched the surface in understanding the evolutionary pathways of venom divergence, which include gene duplication, co-option of existing genes, and natural selection.

William K. Hayes et al, It's a Small World After All: The Remarkable but Overlooked Diversity of Venomous Organisms, with Candidates Among Plants, Fungi, Protists, Bacteria, and Viruses, Toxins (2025). DOI: 10.3390/toxins17030099

Comment by Dr. Krishna Kumari Challa on March 26, 2025 at 10:51am

Since ancestral enzymes no longer exist, scientists use a technique called ancestral sequence reconstruction (ASR) to study their evolution.

ASR combines molecular phylogenetics with genetic and protein engineering to infer and reconstruct the genetic or protein sequences of extinct organisms using phylogenetically related sequences from living species.

3-Isopropylmalate dehydrogenase (IPMDH), an enzyme involved in leucine biosynthesis (the metabolic pathway that synthesizes leucine, one of the 20 proteinogenic amino acids), is an excellent candidate for studying thermostability and cold adaptation due to its extensive evolutionary history.
Researchers traced its evolution from the enzyme of the most ancient thermophilic common ancestor to the mesophilic bacterium Escherichia coli using ASR.
They reconstructed 11 intermediate ancestral enzymes along the evolutionary trajectory connecting the last common bacterial ancestor and E. coli IPMDH (EcIPMDH).
After that, they analyzed changes in enzyme activity at each evolutionary stage, especially improvements in catalytic activity at low temperatures.
They observed a notable increase in catalytic activity at 25 °C, which did not follow a gradual, linear pattern. Instead, a dramatic improvement occurred between the fifth (Anc05) and sixth (Anc06) intermediate ancestors.
To find the underlying molecular mechanisms, the researchers compared the amino acid sequences of the ancestral enzymes and used site-directed mutagenesis, a technique that allows precise alterations to DNA and protein sequences.

They identified three key amino acid substitutions that significantly enhanced catalytic activity at 25 °C. Surprisingly, these mutations occurred far from the active site, challenging the previous belief that temperature adaptation is primarily driven by active-site modifications.

Molecular dynamics simulations revealed a key structural shift between Anc05 and Anc06. While Anc05 remained in an open conformation, Anc06 could adopt a partially closed conformation, reducing activation energy and enhancing enzymatic efficiency at low temperatures.

This transition occurred 2.5–2.1 billion years ago, coinciding with the Great Oxidation Event, which led to a sharp decline in atmospheric methane and global cooling. The researchers suggest that this climate shift may have driven the adaptation of enzymes to lower temperatures.
By identifying key mutations that enhance enzyme efficiency, ASR provides valuable insights into how life evolved in response to Earth's changing environment. Applying this approach to various enzymes is expected to reveal how organisms and their enzymes have evolved in response to Earth's environmental changes over the past four billion years.
Beyond fundamental research, these findings could aid in bioengineering enzymes for applications in biotechnology, pharmaceuticals, and environmental science.

Shuang Cui et al, Insights into the low‐temperature adaptation of an enzyme as studied through ancestral sequence reconstruction, Protein Science (2025). DOI: 10.1002/pro.70071

Part 2

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Comment by Dr. Krishna Kumari Challa on March 26, 2025 at 10:48am

Scientists uncover how enzymes evolved to function at low temperatures

Life has evolved over billions of years, adapting to the changing environment. Similarly, enzymes—proteins that speed up biochemical reactions (catalysis) in cells—have adapted to the habitats of their host organisms. Each enzyme has an optimal temperature range where its functionality is at its peak.

For humans, this is around normal body temperature (37 °C). Deviating from this range causes enzyme activity to slow down and eventually stop. However, some organisms, like bacteria, thrive in extreme environments, such as hot springs or freezing polar waters. These extremophiles have enzymes adapted to function in harsh conditions.

For instance, enzymes from thermophiles, organisms that thrive in high-temperature environments, are heat resistant and show good catalytic activity at high temperatures; declining significantly at lower temperatures. In contrast, enzymes from mesophiles and psychrophiles, organisms that inhabit moderate and cold environments, lack thermostability and show high catalytic activity at lower temperatures.

Evidence suggests that the earliest life forms were thermophiles, which gradually adapted to lower temperatures as Earth cooled. An enzyme's ability to remain catalytically active at lower temperatures is linked to the flexibility of its molecular structure.
However, the precise molecular mechanisms behind this adaptation remain unclear. Understanding how enzymes from thermophilic organisms evolved to function at lower temperatures could not only provide insights into evolutionary biology but also aid in bioengineering enzymes optimized for different temperature conditions.
Part 1

Comment by Dr. Krishna Kumari Challa on March 26, 2025 at 10:23am

This Electronics-free Robot Can Walk Right Off the 3D-Printer

Comment by Dr. Krishna Kumari Challa on March 26, 2025 at 10:13am

Half ice, half fire': Physicists discover new phase of matter in a magnetic material

Scientists  have discovered a new phase of matter while studying a model system of a magnetic material.

The phase is a never-before-seen pattern of electron spins—the tiny "up" and "down" magnetic moments carried by every electron. It consists of a combination of highly ordered "cold" spins and highly disordered "hot" spins, and it has thus been dubbed "half ice, half fire." The researchers discovered the new phase while studying a one-dimensional model of a type of magnetic material called a ferrimagnet.

"Half ice, half fire" is notable not only because it has never been observed before, but also because it is able to drive extremely sharp switching between phases in the material at a reasonable, finite temperature. This phenomenon could one day result in applications in the energy and information technology industries.

The researchers describe their work in the Dec. 31, 2024, edition of the journal Physical Review Letters.

 Weiguo Yin et al, Phase Switch Driven by the Hidden Half-Ice, Half-Fire State in a Ferrimagnet, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.133.266701. On arXiv: arxiv.org/html/2401.00948v2

Comment by Dr. Krishna Kumari Challa on March 25, 2025 at 12:05pm

Why Is It Painful To Bite Aluminum Foil?

Comment by Dr. Krishna Kumari Challa on March 25, 2025 at 9:26am

Triggering parasitic plant 'suicide' to help farmers

Parasitic weeds are ruthless freeloaders, stealing nutrients from crops and devastating harvests. But what if farmers could trick these invaders into self-destructing? Scientists  think they've found a way.

Across sub-Saharan Africa and parts of Asia, places already struggling with food insecurity, entire fields of staples like rice and sorghum can be lost to a group of insidious weeds that drain crops of their nutrients before they can grow. Farmers battle these parasites with few effective tools, but researchers may be able to turn the weeds' own biology against them.

This trick is detailed in the journal Science, and at its heart lies a class of hormones called strigolactones—unassuming chemicals that play dual roles. Internally, they help control growth and the plants' response to stresses like insufficient water. Externally, they do something that is unusual for plant hormones.

Most of the time, plant hormones do not radiate externally—they aren't exuded. But these do. Plants use strigolactones to attract fungi in the soil that have a beneficial relationship with plant roots.

The parasitic weeds have learned to hijack the strigolactone signals, using them as an invitation to invade. Once the weeds sense the presence of strigolactones, they germinate and latch on to a crop's roots, draining them of essential nutrients.

These weeds are waiting for a signal to wake up. We can give them that signal at the wrong time—when there's no food for them—so they sprout and die.

It's like flipping their own switch against them, essentially encouraging them to commit suicide.

This has been seen in lab conditions.

But scientists still have questions about whether the weed suicide strategy will work in real-world fields. They are  testing whether they can fine-tune the chemical signal to be even more effective. If they can, this could be a game-changer for farmers battling these weeds.

Anqi Zhou et al, Evolution of interorganismal strigolactone biosynthesis in seed plants, Science (2025). DOI: 10.1126/science.adp0779

Comment by Dr. Krishna Kumari Challa on March 25, 2025 at 9:19am

Biologists discover ancient neurohormone that controls appetite

A team of biologists has discovered that a neurohormone controlling appetite in humans has an ancient evolutionary origin, dating back over half a billion years. The findings, published in Proceedings of the National Academy of Sciences , reveal that this satiety-inducing molecule, known as bombesin, is not only present in humans and other vertebrates but also in starfish and their marine relatives.

Bombesin, a small peptide, plays a key role in regulating hunger by signaling when we've had enough to eat. But its story doesn't start with humans or even mammals. New research shows that bombesin-like neurohormones have been controlling appetite in animals since long before the first vertebrates evolved on Earth.

The name, bombesin, comes from the fire-bellied toad (Bombina bombina), from whose skin the peptide was first isolated in 1971. When injected into mammals, bombesin was found to reduce meal size and increase the time between meals.

This led scientists to think that bombesin-like neurohormones, produced in the brain and gut, are part of the body's natural system for controlling food intake. Furthermore, alongside weight-loss-inducing drugs such as Ozempic, compounds that mimic the action of bombesin are in development for the treatment of obesity.

By analyzing the genomes of invertebrate animals, the researchers discovered genes encoding bombesin-like neurohormones in the common starfish (Asterias rubens) and other echinoderms, such as sea urchins and sea cucumbers.

This research not only deepens our understanding of the evolutionary history of neurohormones but also highlights the unexpected connections between humans and the strange, stomach-everting world of starfish.

Elphick, Maurice R., Discovery and functional characterization of a bombesin-type neuropeptide signaling system in an invertebrate, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2420966122. doi.org/10.1073/pnas.2420966122

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