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Comment by Dr. Krishna Kumari Challa on September 16, 2025 at 10:13am

Ants defend plants from herbivores, but can hinder pollination by bees

Around 4,000 plant species from different parts of the world secrete nectar outside their flowers, such as on their stems or leaves, through secretory glands known as extrafloral nectaries. Unlike floral nectar, extrafloral nectar does not attract pollinators; rather, it attracts insects that defend plants, such as ants. These insects feed on the sweet liquid and, in return, protect the plant from herbivores. However, this protection comes at a cost.

A study published in the Journal of Ecology points out that the presence of ants can reduce the frequency and duration that bees visit the flowers of plants with extrafloral nectaries.

Pollination is only impaired when extrafloral nectaries are close to the flowers. Plants with these glands in other locations, such as on their leaves or branches, had increased reproductive success, likely due to the protection against herbivores provided by ants.

On the other hand, butterflies, another group of pollinators, are not affected by ants. This may be due to the way these two groups feed. Butterflies use a long, straw-like organ called a proboscis to suck nectar from a distance, keeping them safe from ants.

Bees, on the other hand, need to get very close to the flower to collect pollen and floral nectar, but ants don't allow them to stay for long. Not surprisingly, the new analysis showed that the presence of ants is detrimental to pollination when extrafloral nectaries are close to flowers, but has a positive effect on plant reproduction when they're located further away.

The conclusions are the result of an analysis of data from 27 empirical studies on the relationships between ants, pollinators, and plants with extrafloral nectaries. The articles were selected from an initial screening of 567 studies after applying inclusion and exclusion criteria. The data were compiled and analyzed with computational tools.

Amanda Vieira da Silva et al, Ants on flowers: Protective ants impose a low but variable cost to pollination, moderated by location of extrafloral nectaries and type of flower visitor, Journal of Ecology (2025). DOI: 10.1111/1365-2745.70087

Comment by Dr. Krishna Kumari Challa on September 16, 2025 at 9:49am

The death of the dinosaurs reengineered Earth

Dinosaurs had such an immense impact on Earth that their sudden extinction led to wide-scale changes in landscapes—including the shape of rivers—and these changes are reflected in the geologic record, according to a new study.

Scientists have long recognized the stark difference in rock formations from just before dinosaurs went extinct to just after, but chalked it up to sea level rise, coincidence, or other abiotic reasons. But the new study shows that once dinosaurs were extinguished, forests were allowed to flourish, which had a strong impact on rivers.

Studying these rock layers, the researchers suggest that dinosaurs were likely enormous "ecosystem engineers," knocking down much of the available vegetation and keeping land between trees open and weedy. The result was rivers that spilled openly, without wide meanders, across landscapes. Once the dinosaurs perished, forests were allowed to flourish, helping stabilize sediment and corralling water into rivers with broad meanders.

Their results, published in the journal Communications Earth & Environment, demonstrate how rapidly the Earth can change in response to catastrophic events.

Very often when we're thinking about how life has changed through time and how environments change through time, it's usually that the climate changes and, therefore, it has a specific effect on life, or this mountain has grown and, therefore, it has a specific effect on life. It's rarely thought that life itself could actually alter the climate and the landscape. The arrow doesn't just go in one direction, the researchers say.

 Dinosaur extinction can explain continental facies shifts at the Cretaceous-Paleogene boundary, Communications Earth & Environment (2025). DOI: 10.1038/s43247-025-02673-8

Comment by Dr. Krishna Kumari Challa on September 16, 2025 at 9:43am

Scientists discover how nanoplastics disrupt brain energy metabolism

Scientists have discovered how nanoplastics—even smaller than microplastics—disrupt energy metabolism in brain cells. Their findings may have implications for better understanding neurodegenerative diseases characterized by declining neurological or brain function, and even shed new light on issues with learning and memory.

The study has revealed the specific mechanism by which these tiny nanoplastics can interfere with energy production in the brain in an animal model. The findings, recently published in the Journal of Hazardous Materials: Plastics, provide fresh insights into the potential health risks posed by environmental plastics.

Polystyrene nanoplastics (PS-NPs) are produced when larger plastics break down in the environment. These particles have been detected in multiple organs in the body, including the brain, sparking growing concerns about their possible role in neurological disease.

The researchers focused on mitochondria, which are critical for producing the energy needed for brain function. Mitochondrial dysfunction is a well-known feature of neurodegenerative diseases such as Parkinson's and Alzheimer's, as well as normal aging.

By isolating mitochondria from brain cells, the researchers showed that exposure to PS-NPs specifically disrupted the "electron transport chain," a simplified term for the set of protein complexes that work together to help generate cellular energy in the form of ATP. While individual mitochondrial complexes I and II were not directly impaired, electron transfer between complexes I–III and II–III, as well as the activity of complex IV, was significantly inhibited.

The scientists found that electron transfer between complex I–III and complex II–III was potently inhibited at much lower concentrations, suggesting environmentally relevant exposures could also impair bioenergetic function over chronic timeframes.

Interestingly, the same broad effects were seen in synaptic mitochondria, which are essential for communication between brain cells. This suggests that nanoplastics could also interfere with synaptic plasticity, a process fundamental to learning and memory.

D.M. Seward et al, Polystyrene nanoplastics target electron transport chain complexes in brain mitochondria, Journal of Hazardous Materials: Plastics (2025). DOI: 10.1016/j.hazmp.2025.100003

Comment by Dr. Krishna Kumari Challa on September 16, 2025 at 9:26am

Scientists engineer plants to double carbon uptake ability and produce more seeds and lipids

Typically, plants rely on the Calvin-Benson-Bassham (CBB) cycle to convert carbon dioxide in the atmosphere to usable organic matter for growth. Although this cycle is the main pathway for carbon fixation in all plants on Earth, it is surprisingly inefficient—losing one third of carbon in the cycle when synthesizing the molecule acetyl–coenzyme A (CoA) to generate lipids, phytohormones, and metabolites. Plants also lose carbon during photorespiration, which limits their growth. This is largely due to the inefficiency of an enzyme called RuBisCO.

In efforts to increase carbon uptake and reduce carbon loss in plants to boost biomass and lipid production, scientists have experimented with ways to increase the efficiency of RuBisCO, overexpress CBB cycle enzymes, introduce carbon-concentrating mechanisms, and reduce photorespiration losses. But, a new study published in Science, focuses on a novel approach—creating an altogether new pathway for carbon uptake.

The researchers involved in the study introduced a synthetic CO₂ uptake cycle into the plant Arabidopsis thaliana. They refer to the engineered cycle as the malyl-CoA-glycerate (McG) cycle, which works in conjunction with the CBB cycle to create a dual-cycle CO₂ fixation system. The new cycle increases efficiency by using previously wasted carbon.

"In the McG cycle, one additional carbon is fixed when 3PG is the input, or no carbon is lost when glycolate is the input. In both cases, acetyl-CoA is produced more efficiently, which is expected to enhance the production of lipids and other important plant metabolites, including phytohormones," the authors write.

 Kuan-Jen Lu et al, Dual-cycle CO₂ fixation enhances growth and lipid synthesis in Arabidopsis thaliana, Science (2025). DOI: 10.1126/science.adp3528

Comment by Dr. Krishna Kumari Challa on September 16, 2025 at 7:10am

The sound of crying babies makes our faces hotter, according to new research

Hearing a baby cry can trigger a range of responses in adults, such as sympathy, anxiety and a strong urge to help. However, new research suggests that a deeper physical reaction is also occurring. A baby's cry, particularly if it is in pain or distress, makes our faces physically warmer.

Since they can't speak yet, babies cry to communicate their needs, whether they're in pain or want some attention. When a baby is in distress, they forcefully contract their ribcage, which produces high-pressure air that causes their vocal cords to vibrate chaotically. This produces complex disharmonious sounds known as nonlinear phenomena (NLP).

To study how adults respond to crying babies, scientists played 23 different recordings to 41 men and women with little to no experience with young infants. At the same time, a thermal infrared imaging camera measured subtle changes to their facial temperatures. A rise in temperature in this part of the body is governed by the autonomic nervous system, a network of nerves that controls unconscious processes such as breathing and digestion. After each cry, the participants rated whether the baby was in discomfort or in pain.

The study found that adults' facial temperatures change when they hear a baby cry, a clear sign that the autonomic nervous system has been activated. This suggests that people unconsciously pick up on acoustic features in a baby's cry. The higher the level of NLP (meaning a baby is in more pain or distress), the stronger and more in sync the listener's facial temperature became. In other words, as the cry grew louder, a person's face grew warmer. This physiological reaction was the same for both men and women.

Lény Lego et al, Nonlinear acoustic phenomena tune the adults' facial thermal response to baby cries with the cry amplitude envelope, Journal of the Royal Society Interface (2025). DOI: 10.1098/rsif.2025.0150

Comment by Dr. Krishna Kumari Challa on September 16, 2025 at 7:05am

A pathological partnership between Salmonella and yeast in the gut

Researchers have found that a common gut yeast, Candida albicans, can help Salmonella typhimurium take hold in the intestine and spread through the body. When interacting, a Salmonella protein called SopB prompts the yeast to release arginine, which turns on Salmonella's invasion machinery and quiets the body's inflammation signals.

Gut microbes shape human health across colonization resistance, immune training, digestion, and signaling that reaches distant organs. Bacteria dominate both abundance and research attention, while roles for viruses and fungi remain less defined.

Altered mycobiome composition appears in multiple gastrointestinal diseases, and integration of fungi into gut ecology and into interactions with commensal and pathogenic bacteria remains largely unknown.

Non-typhoidal Salmonella ranks among the best-studied enteric pathogens, infecting an estimated 100 million people each year. Healthy individuals typically experience localized inflammatory diarrhea, while immunocompromised patients face risks of spread to peripheral organs.

Establishing gut colonization requires competition with resident microorganisms, and commensal fungi occur across tested mammalian species, yet mycobiome contributions during enteric infection remain largely unexplored.

Candida albicans is a frequent colonizer of human mucosal surfaces, present in the gut of more than 60% of healthy humans. Usual behavior is commensal, with pathogenic potential particularly in immunocompromised hosts. A key virulence trait is morphology switching from yeast to epithelium-penetrating hyphae.

Associations with inflammatory bowel disease, specifically Crohn's disease, have been reported. C. albicans cannot induce gut inflammation and has been shown to exacerbate it. Both Salmonella and C. albicans thrive under inflammatory gut conditions, and C. albicans likely resides in the gut of many patients at the time Salmonella infection occurs.

In the study, "Commensal yeast promotes Salmonella Typhimurium virulence," published in Nature, researchers investigated cross-kingdom interactions to determine how Candida albicans influences Salmonella colonization, systemic dissemination, and host inflammatory responses.

In the experiments conducted in mice, Candida in the gut led to higher Salmonella loads in the large intestine and more bacteria reaching the spleen and liver, with co-infected mice losing more weight. Candida also boosted Salmonella entry into human colon cell lines. Gene readouts showed Salmonella's invasion machinery switched on near Candida.

Co-cultures contained millimolar arginine, and adding L-arginine alone increased invasion in a dose-dependent way, while an arginine-transporter mutant did not respond to Candida. Candida lacking arginine production also failed to boost Salmonella invasion or gut colonization, and an ARG4 revertant restored the effect.

Researchers conclude that C. albicans colonization represents a susceptibility factor for Salmonella infection, with arginine acting as a pivotal metabolite connecting fungus, bacterium, and host. Findings point to SopB-driven arginine production in Candida that boosts Salmonella's invasion program while softening host inflammatory signals.

 Kanchan Jaswal et al, Commensal yeast promotes Salmonella Typhimurium virulence, Nature (2025). DOI: 10.1038/s41586-025-09415-y

Comment by Dr. Krishna Kumari Challa on September 13, 2025 at 8:40am

Researchers may have found a way to limit the debilitating damage strokes can cause

With limited treatment options for stroke patients available,  researchers are developing an experimental drug that is capable of protecting the brain and improving recovery after a cerebral vascular accident also known as a brain attack.

They targeted a small regulatory biological molecule called microRNA, which becomes abnormally elevated after stroke and promotes inflammation, contributes to tissue loss and causes a decline in neurological function. 

MicroRNAs (miRNAs) are a class of non-coding RNAs, which do not translate into proteins, that play important roles in regulating gene expression. 

So the researchers developed a next-generation inhibitor of this MiRNA to block its harmful effects. 

Unlike traditional experimental drugs that target only a single protein or molecule, this approach simultaneously suppresses multiple damaging processes by targeting several proteins. This reduces brain injury, inflammation, and the damage of the tissue while enhancing protective factors that support repair.

 

 

Source: https://medicalxpress.com/news/2025-09-limit-debilitating.html?utm_...

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Comment by Dr. Krishna Kumari Challa on September 13, 2025 at 8:22am

Microbial allies: Some Bacteria help fight against cancer

An international team of scientists have discovered that microbes associated with tumors produce a molecule that can control cancer progression and boost the effectiveness of chemotherapy.

Most people are familiar with the microbes on the skin or in the gut, but recent discoveries have revealed that tumors also host unique communities of bacteria. Scientists are now investigating how these tumor-associated bacteria can affect tumour growth and the response to chemotherapy.

New research, published online in Cell Systems, provides a significant breakthrough in this field, identifying a powerful anti-cancer metabolite produced by bacteria associated with colorectal cancer.

This finding opens the door to new strategies for treating cancer, including the development of novel drugs that could make existing therapies more potent.

The researchers used a sophisticated large-scale screening approach to test over 1,100 conditions in C. elegans. Through this, they found that the bacteria E. coli produced a molecule called 2-methylisocitrate (2-MiCit) that could improve the effectiveness of the chemotherapy drug 5-fluorouracil (5-FU).

Using computer modeling, the team demonstrated that the tumor-associated microbiome (bacteria found within and around tumors) of patients was also able to produce 2-MiCit. To confirm the effectiveness of 2-MiCit, the team used two further systems; human cancer cells and a fly model of colorectal cancer. In both cases, they found that 2-MiCit showed potent anti-cancer properties, and for the flies could extend survival.

Bacteria are associated with tumors, and now scientists are  starting to understand the chemical conversation they're having with cancer cells.

They found that one of these bacterial chemicals can act as a powerful partner for chemotherapy, disrupting the metabolism of cancer cells and making them more vulnerable to the drug.

The study revealed that 2-MiCit works by inhibiting a key enzyme in the mitochondria (structures inside cells that generate energy for cellular functions) of cancer cells. This leads to DNA damage and activates pathways known to reduce the progression of cancer. This multi-pronged attack weakens the cancer cells and works in synergy with 5-FU. The combination was significantly more effective at killing cancer cells than either compound alone.

These exciting discoveries highlight how the cancer-associated microbiome can impact tumor progression, and how metabolites produced by these bacteria could be harnessed to improve cancer treatments.

These findings are also important in the context of personalized medicine, emphasizing the importance of considering not only the patient, but also their microbes.

Daniel Martinez-Martinez et al, Chemotherapy modulation by a cancer-associated microbiota metabolite, Cell Systems (2025). DOI: 10.1016/j.cels.2025.101397

Comment by Dr. Krishna Kumari Challa on September 13, 2025 at 7:57am

Smells that deceive the brain: Research reveals how certain aromas are interpreted as taste

Flavored drinks without sugar can be perceived as sweet—and now researchers know why. A new study from Karolinska Institutet in Sweden, published in the journal Nature Communications, reveals that the brain interprets certain aromas as taste. The paper is titled "Tastes and retronasal odours evoke a shared flavour-specific neura...

When we eat or drink, we don't just experience taste, but rather a "flavor." This taste experience arises from a combination of taste and smell, where aromas from food reach the nose via the oral cavity, known as retronasal odor.

Researchers  have now shown that the brain integrates these signals earlier than previously thought—already in the insula, a brain region known as the taste cortex—before the signals reach the frontal cortex, which controls our emotions and behavior.

The taste cortex reacts to taste-associated aromas as if they were real tastes.

The finding provides a possible explanation for why we sometimes experience taste from smell alone, for example in flavored waters. This underscores how strongly odors and tastes work together to make food pleasurable, potentially inducing craving and encouraging overeating of certain foods.

The study results showed that aromas that are perceived as sweet or savory not only activate the same parts of the brain's taste cortex as the actual tastes but that they evoke similar patterns of activation. This overlap was particularly evident in the parts of the taste cortex that are linked to the integration of sensory impressions.

This shows that the brain does not process taste and smell separately, but rather creates a joint representation of the flavor experience in the taste cortex.

This mechanism may be relevant for how our taste preferences and eating habits are formed and influenced.

Putu Agus Khorisantono, et al. Tastes and retronasal odours evoke a shared flavour-specific neural code in the human insula, Nature Communications (2025). DOI: 10.1038/s41467-025-63803-6

Comment by Dr. Krishna Kumari Challa on September 12, 2025 at 11:41am

Breathlessness increases long-term mortality risk, finds a study in Malawi

Research led by Liverpool School of Tropical Medicine and the Malawi-Liverpool-Wellcome Program shows that over half of hospital patients with breathlessness had died within a year of admission (51%), as opposed to just 26% of those without the symptom.

Most of these patients had more than one condition that caused breathlessness, including pneumonia, anemia, heart failure and TB.

The findings demonstrate the importance of integrated, patient-centered care, researchers say, to tackle the burden of high mortality for people with breathlessness, particularly in low-income countries. The work appears in Thorax.

Most of these patients live with more than one condition at the same time, which the researchers found to be a factor linked to higher mortality, such as those with TB or pneumonia. This suggests that treating diseases in isolation is not enough, and health care models that have traditionally focused on single presenting conditions may overlook important concurrent diseases.

Acute breathlessness as a cause of hospitalisation in Malawi: a prospective, patient-centred study to evaluate causes and outcomes, Thorax (2025). DOI: 10.1136/thorax-2025-223623

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