Comment

Comment by Dr. Krishna Kumari Challa yesterday

Unlike traditional microscopes that use light or lenses, DNA microscopy creates images by calculating interactions among molecules, providing a new way to visualize genetic material in 3D.

First, short DNA sequence tags called unique molecular identifiers (UMIs) are added to cells. They attach to DNA and RNA molecules and begin making copies of themselves. This starts a chemical reaction that creates new sequences, called unique event identifiers (UEIs), that are unique to each pairing.
It's these pairings that help create the spatial map of where each genetic molecule is located. UMI pairs that are close together interact more frequently and generate more UEIs than those that are farther apart.

Once the DNA and RNA are sequenced, a computational model reconstructs their original locations by analyzing the physical links between UMI-tags, creating a spatial map of gene expression.
DNA microscopy doesn't rely on prior knowledge of the genome or shape of a specimen, so it could be useful for understanding genetic expression in unique, unknown contexts. Tumors generate countless new genetic mutations, for example, so the tool would be able to map out the tumor microenvironment and where it interacts with the immune system.

 Spatial-transcriptomic imaging of an intact organism using volumetric DNA microscopy, Nature Biotechnology (2025). DOI: 10.1038/s41587-025-02613-z

Part 2

Comment by Dr. Krishna Kumari Challa yesterday

DNA microscope creates 3D images of organisms from the inside out

Standard genetic sequencing approaches can tell you a lot about the genetic makeup and activity in a sample, like a piece of tissue or drop of blood. But they don't tell you where specific genetic sequences were located inside that sample, or their relationship to other genes and molecules.

Researchers  are now developing a new technology that overcomes these challenges. By tagging each DNA or RNA molecule and allowing neighboring tags to interact, the technique constructs a molecular network that encodes their relative positions, creating a spatial map of genetic material.

This technique, called volumetric DNA microscopy, creates a 3D image of an entire organism from the inside out, giving scientists an unprecedented view of genetic sequences and where they are located, down to individual cells. 

The researchers have spent more than 12 years developing DNA microscopy.

In a paper published in Nature Biotechnology the researchers used the technology to create a complete DNA image of a zebrafish embryo, a common model organism for studying development and neurobiology.

Part 1

Comment by Dr. Krishna Kumari Challa on Thursday

Liver regeneration was known to occur through the proliferation of liver cells, known as hepatocytes. However, the molecular mechanisms involved were not fully understood. This current discovery is very novel, as it describes communication between two different organs, the liver and bone marrow, involving the immune system.

The results show that liver and bone marrow are interconnected by glutamate. After acute liver damage, liver cells, called hepatocytes, produce glutamate and send it into the bloodstream; through the blood, glutamate reaches the bone marrow, inside the bones, where it activates monocytes, a type of immune system cell.

Monocytes then travel to the liver and along the way become macrophages—also immune cells. The presence of glutamate reprograms the metabolism of macrophages, and these consequently begin to secrete a growth factor that leads to an increase in hepatocyte production.

In other words, a rapid chain of events allows glutamate to trigger liver regeneration in just minutes, through changes in the macrophage metabolism. It is a new, complex and ingenious perspective on how the liver stimulates its own regeneration.
In the liver, there are different types of hepatocytes, organized in different areas; the hepatocytes in each area perform specific metabolic functions.

The study reveals that hepatocytes producing a protein known as glutamine synthetase, which regulates glutamate levels, play a key role in regeneration.
Dietary glutamate supplementation may simply be recommended in the future after liver extirpation, and also to reduce liver damage caused by cirrhosis, which is common in patients with a poor diet or unhealthy lifestyle or other serious liver diseases, say the researchers.

María del Mar Rigual et al, Macrophages harness hepatocyte glutamate to boost liver regeneration, Nature (2025). DOI: 10.1038/s41586-025-08778-6. www.nature.com/articles/s41586-025-08778-6

Part 2

Comment by Dr. Krishna Kumari Challa on Thursday

Rapid liver regeneration: New mechanism is triggered by glutamate just minutes after damage occurs

The liver is a vital organ, crucial to digestion, metabolism and the elimination of toxins. It has a unique ability, regeneration, which allows it to replace liver cells damaged by the very toxins that these cells eliminate. However, the liver stops regenerating in cases of diseases that involve chronic liver damage, such as cirrhosis. Such diseases are becoming increasingly prevalent, associated with bad dietary habits and alcohol.

Learning to activate liver regeneration is therefore a priority today, to benefit mainly patients with severe liver damage and also those who have had part of their liver cut out to remove a tumor.

Research at the National Cancer Research Center (CNIO), published in Nature, has discovered in animal models a previously unknown mechanism of liver regeneration. It is a process that is triggered very quickly, just a few minutes after acute liver damage occurs, with the amino acid glutamate playing a key role.

The authors write that, in light of their results, nutritional glutamate supplementation can effectively promote liver regeneration and benefit patients with severe and chronic liver damage, such as those recovering after hepatectomy, to stimulate liver growth, or even those awaiting a transplant.

Part 1

Comment by Dr. Krishna Kumari Challa on Thursday

Researchers discover new class of antibiotics

The last time a new class of antibiotics reached the market was nearly three decades ago—but that could soon change, thanks to a discovery by researchers .

A team led by researcher Gerry Wright has identified a strong candidate to challenge even some of the most drug-resistant bacteria on the planet: a new molecule called lariocidin. The findings were published in the journal Nature on March 26, 2025.

The discovery of the all-new class of antibiotics responds to a critical need for new antimicrobial medicines, as bacteria and other microorganisms evolve new ways to withstand existing drugs. This phenomenon is called antimicrobial resistance—or AMR—and it's one of the top global public health threats, according to the World Health Organization.

Our old drugs are becoming less and less effective as bacteria become more and more resistant to them. About 4.5 million people die every year due to antibiotic-resistant infections, and it's only getting worse.

A research team found that the new molecule, a lasso peptide, holds great promise as an early drug lead because it attacks bacteria in a way that's different from other antibiotics. Lariocidin binds directly to a bacterium's protein synthesis machinery in a completely new way, inhibiting its ability to grow and survive.

This is a new molecule with a new mode of action. Lariocidin is produced by a type of bacteria called Paenibacillus, which the researchers retrieved from a soil sample . 

The research team allowed the soil bacteria to grow in the lab for approximately one year—a method that helped reveal even the slow-growing species that could have otherwise been missed. One of these bacteria, Paenibacillus, was producing a new substance that had strong activity against other bacteria, including those typically resistant to antibiotics.

When the researchers figured out how this new molecule kills other bacteria, it was a breakthrough moment.

In addition to its unique mode of action and its activity against otherwise drug-resistant bacteria, the researchers are optimistic about lariocidin because it ticks a lot of the right boxes: it's not toxic to human cells, it's not susceptible to existing mechanisms of antibiotic resistance, and it also works well in an animal model of infection.

The research team is now laser-focused on finding ways to modify the molecule and produce it in quantities large enough to allow for clinical development. 

The researchers are now working on ripping this molecule apart and putting it back together again to make it a better drug candidate.

Gerard Wright, A broad-spectrum lasso peptide antibiotic targeting the bacterial ribosome, Nature (2025). DOI: 10.1038/s41586-025-08723-7. www.nature.com/articles/s41586-025-08723-7

Comment by Dr. Krishna Kumari Challa on Thursday

High mortality risk found from increase in hot-dry events

As global warming intensifies and populations continue to grow, the likelihood of extreme high-temperature events is increasing. Hot–dry compound events, in particular, pose a direct threat to human health. High temperatures can have prolonged and delayed effects on people's health; and under conditions of low relative humidity, the mortality associated with extreme heat rises significantly.

Previous climate risk analyses have largely focused on the abnormal state of a single variable, but concurrent extreme events, i.e., compound extreme events, tend to have more severe impacts on the environment and human systems than individual extremes. Therefore, the study of compound extreme events related to both is urgently needed.

A recent study reveals a decadal-scale increase in hot–dry events with a high risk of mortality over the past 20 years.  The findings have recently been published in Atmospheric and Oceanic Science Letters.

Yuting Ma et al, The increase in hot–dry events with a high risk of mortality in China associated with the phase transition of the Atlantic Multidecadal Oscillation, Atmospheric and Oceanic Science Letters (2025). DOI: 10.1016/j.aosl.2025.100609

Comment by Dr. Krishna Kumari Challa on Thursday

How some trees benefit from being struck by lightning

Getting zapped with millions of volts of electricity may not sound like a healthy activity, but for some trees, it is. A new study, published in New Phytologist, reports that some tropical tree species are not only able to tolerate lightning strikes, but benefit from them. The trees may have even evolved to act as lightning rods.

What is clear is that lightning plays an underappreciated role in tree competition. And with lightning on the rise in many regions due to climate change , its influence may increase, potentially favoring lightning-tolerant species like Dipteryx oleifera. Understanding lightning and its role in shaping forests may be important for predicting changes in biodiversity and carbon storage, and for informing tropical reforestation efforts.

 How some tropical trees benefit from being struck by lightning: evidence for Dipteryx oleifera and other large-statured trees, New Phytologist (2025). DOI: 10.1111/nph.70062

Comment by Dr. Krishna Kumari Challa on Thursday

Because of the life-history plasticity common to many amphibians, growth and development can vary independently: for example, tadpoles may grow slowly and thus be smaller than average, yet relatively large for their Gosner stage due to lagging development.

The results showed that tadpoles in 'die-off' ponds at first grew significantly faster, which led to a larger body size over the first month of life. Tadpoles also matured faster in die-off ponds, being on average 0.38 stages ahead in their development.

But once mass mortality started, the rate of growth and development in these pools crashed, so that they were overtaken in body size and stage by those in uninfected or uninfected ponds, and ended up small for their stage at their death from the disease.

Similarly, in infected ponds that ultimately saw no die-off, tadpoles grew significantly faster and developed precociously over the first month of life, so that they were larger in body size as well as on average 1.7 Gosner stages ahead of tadpoles in uninfected ponds.
The authors conclude that tadpoles respond to the presence of ranavirus by speeding up their growth rate and progressing through successive developmental stages faster early in life.

Accelerating growth and resource allocation early on may allow tadpoles to improve their physical condition, and thus the strength of their immunity, in anticipation of infection. They might also metamorphose and move onto land earlier, potentially reducing their exposure to ranavirus.
These responses are likely to give tadpoles a survival advantage.

Logan Scott Billet, et al. Sublethal effects of a mass mortality agent: pathogen-mediated plasticity of growth and development in a widespread North American amphibian, Frontiers in Amphibian and Reptile Science (2025). DOI: 10.3389/famrs.2025.1529060

Comment by Dr. Krishna Kumari Challa on Thursday

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 Wednesday

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+...

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