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Comment by Dr. Krishna Kumari Challa 4 hours ago

Serotonin produced by gut bacteria provides hope for a novel IBS treatment

New research clarifies the complex interaction between gut bacteria and irritable bowel syndrome (IBS). Experiments demonstrate that gut bacteria can produce the important substance serotonin. The finding may lead to future treatments.

IBS is a common gastrointestinal disorder, more common in women, with symptoms such as abdominal pain, constipation or diarrhea. The cause of the disease is not clear, but the intestinal environment, including the gut microbiota and serotonin, appear to be important factors.

Serotonin is best known as a neurotransmitter in the brain, but over 90% of the body's serotonin is produced in the gut, where it controls bowel movements via the enteric nervous system, sometimes called the "gut–brain."

Previous research has shown that the bacteria in the gut, the gut microbiota, affect how much serotonin is produced by the host, but until now it has been unclear whether gut bacteria themselves can form biologically active serotonin.

In the current study, published in the journal Cell Reports, the researchers have identified two bacteria that together can produce serotonin: Limosilactobacillus mucosae and Ligilactobacillus ruminis.

When the bacteria were introduced into germ-free mice with serotonin deficiency, the levels of serotonin in the gut increased, as did the density of nerve cells in the colon. The bacteria also normalized the intestinal transit time.

 Researchers were also able to see that people with IBS had lower levels of one of the bacteria (L. mucosae) in their stools compared to healthy individuals, and that this bacterium also has the enzyme required for serotonin production.

The results indicate that certain intestinal bacteria can produce bioactive serotonin and thus play an important role in intestinal health and open new avenues for the treatment of functional gastrointestinal disorders such as IBS.

Chiara H. Moretti et al, Identification of human gut bacteria that produce bioactive serotonin and promote colonic innervation, Cell Reports (2025). DOI: 10.1016/j.celrep.2025.116434. www.cell.com/cell-reports/full … 2211-1247(25)01205-7

Comment by Dr. Krishna Kumari Challa 4 hours ago

Graying hair may reflect a natural defense against cancer risk

Throughout life, our cells are constantly exposed to environmental and internal factors that can damage DNA. While such DNA damage is known to contribute to both aging and cancer, the precise connection—particularly how damaged stem cells shape long-term tissue health—has remained elusive.

Melanocyte stem cells (McSCs) are tissue‐resident stem cells that serve as the source of mature melanocytes, the pigment‐producing cells responsible for hair and skin coloration. In mammals, these stem cells reside in the bulge–sub‐bulge region of hair follicles as immature melanoblasts, maintaining pigmentation through cyclical regeneration.

Published in Nature Cell Biology, a study used long-term in vivo lineage tracing and gene expression profiling in mice to investigate how McSCs respond to different types of DNA damage.

Researchers identified a specific response to DNA double-strand breaks: senescence-coupled differentiation (seno-differentiation), a process in which McSCs irreversibly differentiate and are then lost, leading to hair graying. This process is driven by activation of the p53–p21 pathway.

In contrast, when exposed to certain carcinogens, such as 7,12-dimethylbenz(a)anthracene or ultraviolet B, McSCs bypass this protective differentiation program—even in the presence of DNA damage. Instead, they retain self-renewal capacity and expand clonally, a process supported by KIT ligand secreted both from the local niche and within the epidermis. This niche-derived signal suppresses seno-differentiation, tipping McSCs toward a tumor-prone fate.

These findings reveal that the same stem cell population can follow antagonistic fates—exhaustion or expansion—depending on the type of stress and microenvironmental signals. It reframes hair graying and melanoma not as unrelated events, but as divergent outcomes of stem cell stress responses.

Importantly, this study does not suggest that graying hair prevents cancer, but rather that seno-differentiation represents a stress-induced protective pathway that removes potentially harmful cells. Conversely, when this mechanism is bypassed, the persistence of damaged McSCs may predispose to melanomagenesis.

By identifying the molecular circuits that govern this fate bifurcation, the study provides a conceptual framework that links tissue aging and cancer, and highlights the beneficial role of eliminating potentially harmful stem cells through natural "senolysis," resulting in a phenotype that safeguards against cancer.

 Yasuaki Mohri et al, Antagonistic stem cell fates under stress govern decisions between hair greying and melanoma, Nature Cell Biology (2025). DOI: 10.1038/s41556-025-01769-9

Comment by Dr. Krishna Kumari Challa yesterday

Scientists Just Discovered a Whole New Type of Connection Between Neurons

Super-resolution microscopes have revealed a whole new type of connection between neurons in mouse and human brains.

In the lab,  researchers identified tiny tubular bridges in the branching tips of cultured neurons. In further tests on mouse models of Alzheimer's disease, it appeared the bridges were shuttling calcium and disease-related molecules directly between cells.

Similar] structures can transport a vast range of materials, from small ions (10⁻¹⁰m) to large mitochondria (10⁻⁶ m)," the team writes in their paper.

In cultured neurons, we observed these nanotubes forming dynamically and confirmed that they possessed a distinct internal structure, setting them apart from other neuronal extensions.

Neurons are well known for passing rapid messages to each other using synapses to transmit both electrical and chemical information. Yet, other cell types are known to use physically connecting bridging tubes to exchange molecules. Researchers have just confirmed that a similar type of tube bridge occurs in neurons too, using advanced imaging and machine learning.

The researchers observed the nanotubes transporting amyloid-beta molecules that they had injected into mouse brain cells. These molecules have been implicated in neurodegenerative diseases like Alzheimer's, where they tend to clump together abnormally. When researchers stopped the bridges from forming, the amyloid-beta stopped spreading between cells, too, confirming that the nanotubes acted as direct conduits.

The computational model supported these findings, predicting that overactivation in the nanotube network could accelerate the toxic accumulation of amyloid in specific neurons, thereby providing a mechanistic link between nanotube alterations and the progression of Alzheimer's pathology," the researchers explain. 

https://www.science.org/doi/10.1126/science.adr7403

Comment by Dr. Krishna Kumari Challa yesterday

Bats' brains reveal a global neural compass that doesn't depend on the moon and stars

Some 40 kilometers east of the Tanzanian coast in East Africa lies Latham Island, a rocky, utterly isolated and uninhabited piece of land about the size of seven soccer fields. It was on this unlikely patch of ground that  researchers recorded—for the first time ever—the neural activity of mammals in the wild.

In their study, published in Science, the team used a tiny device to record, at the level of single neurons, the brain activity of fruit bats as they flew around the island. The scientists discovered that the bats' neuronal "compass" is global: It provides stable directional information across the entire island and does not depend on the moon or stars.

Many species share the behavioral ability to orient themselves using an "internal compass," and it is quite possible that humans rely on the same neural mechanism that was studied in these bats.

They found that every time the bats flew with their heads pointing in a particular direction—north, for instance—a unique group of neurons became active, creating an "internal compass." Navigation by means of directional neurons had previously been observed in the lab, but this was the first evidence that it happens in nature as well. When the researchers analyzed the recordings from different parts of the island, they discovered that the activity of the head-direction cells was consistent and reliable across the entire island, enabling the bats to orient themselves over a large geographical area.

 The compass is global and uniform: No matter where the bat is on the island and no matter what it sees, specific cells always point in the same direction—north stays north and south stays south. 

 Shaked Palgi et al, Head-direction cells as a neural compass in bats navigating outdoors on a remote oceanic island, Science (2025). DOI: 10.1126/science.adw6202. www.science.org/doi/10.1126/science.adw6202

Comment by Dr. Krishna Kumari Challa yesterday

Comprehending the expansion of the universe without using 'Dark Energy'

Why is the universe expanding at an ever-increasing rate? This is one of the most exciting yet unresolved questions in modern physics. Because it cannot be fully answered using our current physical worldview, researchers assume the existence of a mysterious "dark energy." However, its origin remains unclear to this day.

An international research team has come to the conclusion that the expansion of the universe can be explained—at least in part—without dark energy.

In physics, the evolution of the universe has so far been described by the general theory of relativity and the so-called Friedmann equations. However, in order to explain the observed expansion of the universe on this basis, an additional "dark energy term" must be manually added to the equations.

This unsatisfactory solution prompted the researchers to take a different approach. Their findings, published in the Journal of Cosmology and Astroparticle Physics, are based on an extension of general relativity (GR) by the later developed model of Finsler gravity. Unlike the original explanatory approach of GRT, the Finsler model allows for a more accurate modeling of the gravitational force of gases, as it is based on a more general spacetime geometry than GRT.

When the research team calculated the Finsler extension of the Friedmann equations, they made an exciting discovery: The Finsler-Friedmann equations already predict an accelerated expansion of the universe in a vacuum—without the need to introduce additional assumptions or "dark energy" terms.

We may now be able to explain the accelerated expansion of the universe without dark energy, based on a generalized spacetime geometry, say the researchers. The new geometry opens up completely new possibilities for better understanding the laws of nature in the cosmos.

Christian Pfeifer et al, From kinetic gases to an exponentially expanding universe—the Finsler-Friedmann equation, Journal of Cosmology and Astroparticle Physics (2025). DOI: 10.1088/1475-7516/2025/10/050. On arXiv (2025). DOI: 10.48550/arxiv.2504.08062

Comment by Dr. Krishna Kumari Challa on Saturday

'Wetware': Scientists use human mini-brains to power computers

Wetware (brain), a term drawn from the computer-related idea of hardware or software, but applied to biological life forms.

'Wetware': Scientists use human mini-brains to power computers

Ten universities around the world are conducting experiments using FinalSpark's organoids -- the small company's website even has a live feed of the neurons at work.

Inside a lab in the picturesque Swiss town of Vevey, a scientist gives tiny clumps of human brain cells the nutrient-rich fluid they need to stay alive.

It is vital these mini-brains remain healthy, because they are serving as rudimentary computer processors—and, unlike your laptop, once they die, they cannot be rebooted.

This new field of research, called biocomputing or "wetware," aims to harness the evolutionarily honed yet still mysterious computing power of the human brain.

The scientists think that that processors using brain cells will one day replace the chips powering the artificial intelligence boom.

The supercomputers behind AI tools like ChatGPT currently use silicon semiconductors to simulate the neurons and networks of the human brain. Instead of trying to mimic, these scientists are using the real thing.

Among other potential advantages, biocomputing could help address the skyrocketing energy demands of AI, which have already threatened climate emissions targets and led some tech giants to resort to nuclear power.

Biological neurons are one million times more energy efficient than artificial neurons, these scientists say. They can also be endlessly reproduced in the lab, unlike the massively in-demand AI chips made by companies like behemoth Nvidia.

But for now, wetware's computing power is a very long way from competing with the hardware that runs the world.

Source: News agencies

https://www.newindianexpress.com/lifestyle/tech/2025/Oct/17/wetware...'Wetware'%3A%20Scientists%20use%20human%20mini%2Dbrains%20to%20power%20computers

Comment by Dr. Krishna Kumari Challa on Friday

What happens when the cell's 'antenna' malfunctions?

Researchers have uncovered the molecular mechanisms responsible for regulating a structure that plays a critical role in how cells communicate with their environment. Their new study has been published in Communications Biology.

Found on the surface of almost every cell, the primary cilium is a tiny antenna-like projection that enables the cell to sense environmental signals. Through this structure, cells regulate essential processes such as growth, development, and adaptation. For healthy functioning, primary cilia must maintain the correct length, stability, and morphology.

The research highlights the role of DYRK kinases, a family of enzymes that regulate intracellular processes. The findings  show that these kinases are essential for maintaining the length, stability, and shape of primary cilia.

When DYRK kinases malfunction, cilia may become abnormally long, structurally deformed, or unstable. In such cases, the cell loses its ability to properly sense and process external signals.

This discovery not only advances our understanding of fundamental cell biology but also provides new perspectives on health conditions linked to ciliary dysfunction, such as developmental disorders, kidney diseases, and vision loss. Moreover, it may open new avenues for addressing complex diseases in the future by uncovering potential targets for therapeutic intervention.

 Melis D. Arslanhan et al, Kinase activity of DYRK family members is required for regulating primary cilium length, stability and morphology, Communications Biology (2025). DOI: 10.1038/s42003-025-08373-5

Comment by Dr. Krishna Kumari Challa on Friday

Older fathers linked to more new gene mutations in puppies, study finds

An international study has shown how and when entirely new gene mutations, known as de novo mutations, originate in dogs. A key finding is that higher paternal age increases the number of de novo mutations in puppies. Maternal age also has an effect.

The study analyzed 390 parent–offspring trios. Trio denotes a design where the genomes of the puppy and both parents are sequenced. This enables accurately identifying gene mutations that do not occur in either parent's genome—mutations that have taken place in the sperm, the ovum or soon after conception. While these rare mutations are the basis of evolution, they can also predispose their carriers to hereditary diseases.

The results, published in Genome Biology, also show why dogs differ from humans in certain genomic regions and what the findings mean for canine health and breeding.

Shao-Jie Zhang et al, Determinants of de novo mutations in extended pedigrees of 43 dog breeds, Genome Biology (2025). DOI: 10.1186/s13059-025-03804-2

Comment by Dr. Krishna Kumari Challa on Friday

Comment by Dr. Krishna Kumari Challa on Friday

How to STOP A Dog Attack BEFORE It Happens!

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