Comment

Comment by Dr. Krishna Kumari Challa on August 21, 2025 at 10:39am

Brain scans reveal action-based organization in people born without hands

Conventional wisdom among neuroscientists suggests that the brain's motor functions are organized around the body, meaning certain brain areas control the hand; others the foot. An emerging alternative theory is that parts of the brain may be organized by the types of action, like reaching or using tools, no matter which body part is used to complete the task.

Researchers  recently set out to understand these theories, because knowing how the brain is organized around function versus body part has profound implications for rehabilitation and a person's return to function following a brain injury.

The findings are published in the Proceedings of the National Academy of Sciences. The work is titled "Action-type mapping principles extend beyond evolutionarily-conserved actions, even in people born without hands."

If motor control is partly based on actions rather than body parts, it's possible the brain can use this flexibility to compensate for the loss of specific limbs.

To gain a deeper understanding of the emerging theory, neuroscientists conducted a novel study with volunteers who were born without hands, and instead use their feet for everyday tasks with and without tools.

Using fMRI brain scans, the researchers showed that in these individuals, brain areas typically involved in hand tool use are still active—even though the individuals were using their feet, not their hands. This finding is consistent with the same action preference for control participants, who perform the action with either their hands or feet.

They  found that some regions in the brain care about the type of action a person is doing and not whether this action was performed with the hand or with the foot.

It appears this organization can arise without typical motor experience, providing evidence for action-type as a core driving factor in motor organization and development.

Interestingly, this was not true for all brain areas.

The primary motor cortex, which is tightly mapped to the body, did not reorganize for foot-based tool use, even in people who have been using tools with their feet their whole lives. This suggests that some brain areas demonstrate more plasticity than others.

Still, the study reveals a kind of brain organization that goes beyond the body—one that is abstract and action-centered, and that develops even without typical experience.

 Florencia Martinez-Addiego et al, Action-type mapping principles extend beyond evolutionarily conserved actions, even in people born without hands, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2503188122

Comment by Dr. Krishna Kumari Challa on August 21, 2025 at 10:28am

Saharan bacteria shield themselves with biofilms to survive dust storm journeys

How do living bacteria survive on the surface of dust particles carried by desert storms from the Sahara and Egypt to Israel?

Researchers  discovered that these bacteria can form microscopic biofilms over dust particles. These protective structures shield the bacteria from desiccation, extreme radiation, and severe nutrient scarcity during their atmospheric journey.

The research, published in Communications Earth and Environment, contributes to the growing field of atmospheric microbiology. This discipline explores the survival and activity of microorganisms while in the atmosphere, sometimes over thousands of kilometers, and their impact on global cycles, ecosystems, and human health. These processes significantly impact disease patterns, atmospheric CO₂ levels, plant diseases, and even antibiotic resistance dispersal.

In this study, the researchers successfully isolated and cultured bacteria brought in by dust storms under atmospheric conditions, focusing on beneficial Bacillus strains known for their positive applications in agriculture, construction, and medical probiotics.

The team thinks that natural selection during dust storms favors more innovative bacterial strains—a phenomenon that could potentially enhance their practical applications. This study also expands the traditional soil microbiome concept to include airborne microbial communities, broadening the known repertoire of survival strategies among these remarkable organisms.

Naama Lang-Yona et al, Bacillus biofilm formation and niche adaptation shape long-distance transported dust microbial community, Communications Earth & Environment (2025). DOI: 10.1038/s43247-025-02534-4

Comment by Dr. Krishna Kumari Challa on August 21, 2025 at 10:22am

Mitochondria defend cells against infections by competing with pathogens for nutrients

Chronic infections impact a substantial portion of the global population, presenting ongoing challenges to health care systems and compromising patient well-being.

In a new study, researchers have discovered a surprising ally in the fight against infection: the cell's own mitochondria. Best known for providing energy to cells, mitochondria also play a defensive role by competing with pathogens for vital nutrients.

The paper is published in the journal Science.

During infection, mitochondria enter a metabolic tug-of-war with intracellular parasites, like Toxoplasma gondii, battling for access to folate, thereby inhibiting pathogen growth.

This discovery highlights a unique defensive strategy employed by host cells and opens up new possibilities for developing therapies against folate-dependent pathogens, such as Toxoplasma and Plasmodium, which cause toxoplasmosis and malaria respectively.

During infection with the human parasite Toxoplasma gondii, researchers observed the activation of the integrated stress response, which rewires mitochondrial metabolism.

This response enhanced mitochondrial activity, leading to increased demand for folate, a critical nutrient for nucleotide synthesis. Consequently, mitochondria limit the parasite's access to folate, curtailing its growth and proliferation. Mice unable to activate this stress response showed faster parasite growth, confirming the pathway's protective role in vivo.

 Tânia Catarina Medeiros et al, Mitochondria protect against an intracellular pathogen by restricting access to folate, Science (2025). DOI: 10.1126/science.adr6326

Comment by Dr. Krishna Kumari Challa on August 21, 2025 at 9:22am

The team also wants to see if epigenetic noise is amplified for wound healing and tissue repair, and whether or not it can be leveraged to reprogram cells to alternate phenotypes for various clinical contexts, including cancer immunotherapy and treating autoimmunity.

It makes sense that to empower an immune system that uses a random process to recognize virtually any entity in the universe, thymic epithelial cells amplify random noise in the genome to ensure the immune system is focused on pathogens and cancers and not its own tissues. It's fighting fire with fire
Sometimes the random background noise can be just as important as the signal.

Thymic epithelial cells amplify epigenetic noise to promote immune tolerance, Nature (2025). DOI: 10.1038/s41586-025-09424-x

Part 3

**

Comment by Dr. Krishna Kumari Challa on August 21, 2025 at 9:21am

Since such heterogeneity is important, they used a series of single cell sequencing techniques to study gene expression and chromatin structure in individual mTECs, instead of using traditional bulk sequencing tools that average the results over thousands of cells.

Chromatin is the complex of DNA and proteins in the nucleus that packages long stretches of DNA into more compact structures. When chromatin is more loosely packed, or open, genes are more poised to be activated than if it's tightly coiled.

When the researchers analyzed the data, they did not find links between peak levels of chromatin accessibility and the expression of tissue-specific genes. Instead, they saw a lot of accessibility "noise" that gave cells the potential to activate genes solely expressed in other specialized tissues. This "ectopic expression" in turn helped train T cells to discriminate between self and non-self.

Chromatin is usually tightly regulated to sequester regions that encode other cell fates and focus accessibility for regions pertinent for the established cell identity.
In this work context, the researchers found the genomic regions that should be tightly packed were more labile or 'jiggly," allowing more opportunities for factors to access and activate genes specific to different cell types."
The team then tried to understand how this "chromatin noise" is amplified in cells. They found that the activity of the tumor suppressor protein p53, known as "the guardian of the genome," is repressed by mTECs prior to their genome becoming noisy. p53 is usually activated when DNA is damaged and can trigger cell death or stop tumor cell growth.

So, it made sense to the researchers that it would be implicated in a process where epithelial cells promiscuously express genes dedicated to other tissues and organs.
When the researchers genetically engineered p53 activity to be enhanced in mTECs, their chromatin became more stable, epigenetic noise was turned down, and the cells could no longer activate tissue-specific genes. This ultimately resulted in the escape of self-reactive T cells from the thymus to cause multi-organ autoimmune disease.
This suggests that thymic epithelial cells adopt deviant states that should normally trigger p53 activation and cell death.But because p53 is downregulated, the cells survive and facilitate this ectopic gene expression to promote the self/non-self discrimination.
It's a fascinating idea to think that cells are programmed to loosen their grip on genes to give them more freedom to get creative and solve problems like preventing T cells from attacking their own tissues.
The researchers extended their studies and found that epigenetic noise also allows lung cancer to sample more of the genome once p53 is deleted. This activates programs specific to other tissues to develop into more aggressive, malignant states. They hope to continue studying whether other cancer types exploit similar mechanisms for tumorigenesis.
Part 2

Comment by Dr. Krishna Kumari Challa on August 21, 2025 at 9:17am

Epigenetic noise: Unappreciated process helps cells change identity

All cells in the body contain the same DNA, but different cell types express different genes; skin cells express genes for the skin, liver cells express liver genes, and so on. This coordination is crucial to help cells differentiate into their assigned roles, but a new study by researchers shows how cells can randomly "shake up" regions of the genome to express genes normally reserved for other cell types.

The study, "Thymic epithelial cells amplify epigenetic noise to promote immune tolerance," published in Nature, suggests that randomness or variability in the way DNA is packaged can create a kind of "epigenetic noise," enabling cells to take on the identity of different cell types. This flexibility plays an important role in tissue repair and the immune system but can also be exploited for the development of tumors.

The researchers worked with an incredibly resourceful group of cells called medullary thymic epithelial cells (mTECs). These cells are found in the thymus, a small, specialized organ of the immune system located just above the heart. They are one of the few cell types in the body that can express a wide variety of genes and alter their identity to mirror cell types from other tissues.

mTECs play an important role in training the immune system to prevent autoimmunity. They present proteins that are normally expressed only in specialized tissues and organs to T cells developing in the thymus. Then, the T cells that react too strongly to molecules from the body's own cells are purged so they don't later trigger an autoimmune response.

The capability to express almost any gene and alter their identities makes mTECs a great candidate for studying how cells can change their fates.

Each individual cell does not express the entire genome. Instead, they express only a unique subset of the tissue-specific genes at any given snapshot. There's a great deal of heterogeneity, so the researchers thought that it was really important to look cell-by-cell to uncover the mechanisms that allow the activation of each subset of tissue-specific genes.

Part 1

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 12:09pm

“Logic will get you from A to B.  Imagination will take you everywhere.” –Albert Einstein

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 12:08pm

Imagination won't take you everywhere—study reveals limitations of the mind's eye

Our imagination might not be as powerful as we think when it comes to holding visual images, according to a first-of-its-kind study by psychologists.

 The research found that people can remember more items when they've seen them, compared to when they must imagine them.

While short-term visual memory can hold three to four items at once, our imagination can manage only two items before becoming less accurate.

Across a series of five experiments, more than 150 participants were asked to either remember or imagine the locations of objects on a grid.

Researchers examined how accurately participants could detect changes in specific locations under various conditions, including timing, cueing, display type, and object complexity. They then compared the number of items participants could correctly remember after viewing them with the number they could accurately imagine and recall without having seen them.

Findings showed that even when given more time or simpler images, people still imagined fewer items than they could remember visually.

The study, "The relation between the capacities of imagination and visual memory in the short-term," published in the Journal of Experimental Psychology: Human Perception and Performance, offers the first direct comparison of how much information people can hold in visual imagination versus visual memory.

Imagination and memory use similar parts of the brain, but this is the first time scientists have measured exactly how they differ when it comes to capacity. These findings demonstrate that actually seeing something, even a brief glimpse, gives our brain extra sensory support that bolsters our memory. In fact, researchers estimate that 17–35% of visual memory capacity depends on sensory input. When we imagine something from scratch, we don't have that input from our eyes, so it's harder to hold detailed images.

We use imagination constantly in everyday life, as imagery is seen as essential for navigating and predicting our environment and is involved in decision-making and emotion regulation, but the study reveals that our capacity to visualize is surprisingly limited, and this might affect how we make decisions, remember plans, or follow instructions when we rely on mental imagery alone.

Christopher Atkin et al, The relation between the capacities of imagination and visual memory in the short term., Journal of Experimental Psychology: Human Perception and Performance (2025). DOI: 10.1037/xhp0001364

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 11:37am

Hight-salt diet sparks brain inflammation that could explain stubborn high blood pressure

A new study finds that a high-salt diet triggers brain inflammation that drives up blood pressure. 

The research suggests the brain may be a missing link in certain forms of high blood pressure—or hypertension—traditionally attributed to the kidneys.

This is new evidence that high blood pressure can originate in the brain, opening the door for developing treatments that act on the brain.

Hypertension affects two-thirds of people over 60 and contributes to 10 million deaths worldwide each year. Often symptomless, the condition increases the risk of heart disease, stroke and other serious health problems.

About one-third of patients don't respond to standard medications, which primarily target the blood vessels and kidneys based on the long-standing view that hypertension begins there.

The study, published in the journal Neuron, suggests the brain may also be a key driver of the condition, particularly in treatment-resistant cases.

How salt disrupts the brain

To mimic human eating patterns, rats were given water containing 2% salt, comparable to a daily diet high in fast food and items like bacon, instant noodles and processed cheese.

The high-salt diet activated immune cells in a specific brain region, causing inflammation and a surge in the hormone vasopressin, which raises blood pressure. Researchers tracked these changes using cutting-edge brain imaging and lab techniques that only recently became available.

The brain's role in hypertension has largely been overlooked, in part because it's harder to study.

The researchers used rats instead of the more commonly studied mice because rats regulate salt and water more like humans. That makes the findings more likely to apply to people.

Next, the scientists plan to study whether similar processes are involved in other forms of hypertension.

Ning Gu et al, Microglia regulate neuronal activity via structural remodeling of astrocytes, Neuron (2025). DOI: 10.1016/j.neuron.2025.07.024

Comment by Dr. Krishna Kumari Challa on August 20, 2025 at 11:31am

To examine the mechanisms behind the link between cardiovascular disease and cancer growth, the study authors developed a mouse model with breast tumors and induced temporary ischemia in one hind limb. The team then compared cancer growth in mice with and without impaired blood flow.

Their findings build on the nature of the immune system, which evolved to attack invading bacteria and viruses, and, under normal conditions, to detect and eliminate cancer cells. These protective functions rely on stem cell reserves in the bone marrow, which can be activated as needed to produce key white blood cell populations throughout life.

Normally, the immune system responds to injury or infection by ramping up inflammation to eliminate threats, then scaling back to avoid harm to healthy tissue. This balance is maintained by a mix of immune cells that either activate or suppress inflammation.

The researchers found that reduced blood flow disrupts this equilibrium. It reprograms stem cells in the bone marrow to favor the production of "myeloid" immune cells (monocytes, macrophages, neutrophils) that dampen immune responses, while reducing output of lymphocytes like T cells that help to mount strong anti-tumor responses.

The local environment within tumors showed a similar shift, accumulating more immune-suppressive cells– including Ly6Chi monocytes, M2-like F4/80+ MHCIIlo macrophages, and regulatory T cells—that shield cancer from immune attack.

Further experiments showed that these immune changes were long-lasting. Ischemia not only altered the expression of hundreds of genes, shifting immune cells into a more cancer-tolerant state, but also reorganized the structure of chromatin–the protein scaffolding that controls access to DNA–making it harder for immune cells to activate genes involved in fighting cancer.
results reveal a direct mechanism by which ischemia drives cancer growth, reprogramming stem cells in ways that resemble aging and promote immune tolerance.
These findings open the door to new strategies in cancer prevention and treatment, like earlier cancer screening for patients with peripheral artery disease and using inflammation-modulating therapies to counter these effects."

Moving forward, the research team hopes to help design clinical studies that evaluate whether existing inflammation-targeted therapies can counter post-ischemic changes driving tumor growth.

Ischemic Injury Drives Nascent Tumor Growth via Accelerated Hematopoietic Aging, JACC CardioOncology (2025). DOI: 10.1016/j.jaccao.2025.05.016

Part 2

• ‹ Previous
• 1
• …
• 12
• 13
• 14
• 15
• 16
• …
• 1112
• Next ›
• Page