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Comment by Dr. Krishna Kumari Challa on April 5, 2025 at 11:24am

Scientists reveal new toxin that damages the gut

Scientists  have discovered how a diarrhea-causing strain of bacteria uses "molecular scissors" to cut open and destroy gut cells, leading to severe illness and sometimes death.

Published in Gut Microbes, the research reveals for the first time the three-dimensional structure of a toxin secreted by enteropathogenic E. coli (EPEC) bacteria, and shows how the bacteria use the toxin to invade and destroy the epithelial cells that line the gut.

The toxin, which is an enzyme called EspC, destroys the cells by cutting up their internal protein structure.

There are more than five types of E. coli that damage epithelial cells in different ways to cause gut infection.

These include STEC, which was responsible for the recent salad spinach recall and uses Shiga toxin to invade gut cells, and EPEC—the subject of this study—which uses the toxin EspC and is the leading cause of diarrhea in children and babies worldwide.

Currently, infections caused by the many diverse strains of E. coli are typically treated with broad-spectrum antibiotics. However, these drugs kill both harmful and beneficial gut bacteria, and E. coli's rapid adaptation ability means these pathogens are becoming resistant to many antibiotics.

 Akila U. Pilapitiya et al, The crystal structure of the toxin EspC from enteropathogenic Escherichia coli reveals the mechanism that governs host cell entry and cytotoxicity, Gut Microbes (2025). DOI: 10.1080/19490976.2025.2483777

Comment by Dr. Krishna Kumari Challa on April 5, 2025 at 11:18am

Artificial sweetener shows surprising power to overcome antibiotic resistance

Saccharin, the artificial sweetener used in diet foods like yogurts and sugar-free drinks, can kill multidrug-resistant bacteria—including one of the world's most dangerous pathogens.

In 2019, antimicrobial resistance (AMR) killed 1.27 million people globally, with resistant infections contributing to nearly 5 million deaths.

Drug-resistant bacteria such as Acinetobacter baumannii, which causes life-threatening infections in people with a weakened immune system, and Pseudomonas aeruginosa, linked to chronic lung infections and sepsis, are on the World Health Organization's list of top-priority pathogens.

Researchers now  have identified a novel antimicrobial—saccharin. 

 Saccharin breaks the walls of bacterial pathogens, causing them to distort and eventually burst, killing the bacteria. Crucially, this damage lets antibiotics slip inside, overwhelming their resistance systems.

Saccharin has been part of the human diet for longer than 100 years. While it has been extensively tested for safety in people, little was known about its effect on bacteria—until now with a study appearing in EMBO Molecular Medicine.

The research team found that saccharin both stops bacterial growth and disrupts DNA replication and stops the bacteria from forming biofilms—sticky, protective layers that help them survive antibiotics.

They also created a saccharin-loaded hydrogel wound dressing that, in tests, outperformed market-leading silver-based antimicrobial dressings currently used in hospitals.

Artificial sweeteners are found in many diet and sugar-free foods. Now scientists discovered that the same sweeteners you have with your coffee or in a 'sugar-free' drink could make some of the world's most dangerous bacteria easier to treat.

Rubén de Dios et al, Saccharin disrupts bacterial cell envelope stability and interferes with DNA replication dynamics, EMBO Molecular Medicine (2025). DOI: 10.1038/s44321-025-00219-1

Comment by Dr. Krishna Kumari Challa on April 5, 2025 at 10:59am

Research  reveals signs of life in Earth's extremes, boosting search for alien life

New research  focused on identifying signs of life—biosignatures—in extreme environments here on Earth. Researchers investigated whether microbial active motion (e.g., swimming), morphology, and optical properties could serve as biosignatures using in situ video microscopy at a range of extreme field sites, many of which had not been previously explored with this technique.

These environments are considered strong analogs for extraterrestrial settings, such as those found on other planets and moons in our solar system.

The researchers found that at least one of the three biosignatures (motion, morphology, or optical properties) was present in every environmental sample tested, ranging from hot deserts to Arctic ice and alkaline springs.

This supports the idea that even in extreme environments, some fraction of microbes exhibit detectable life-indicating characteristics.

This research also highlights digital holographic microscopy (DHM) as a promising tool for future space missions analyzing liquid samples in search of life. It also emphasizes the ubiquity of microbial swimming as a potential biosignature.

To explore this further, researchers introduced chemical and thermal stimuli to test their effects on microbial motility. The responses varied—some environments showed strong microbial reactions, while others showed little to none.

Despite these differences, a consistent finding across all sites was the presence of microbial biosignatures wherever was explored with DHM.

Carl D. Snyder et al, Extant life detection using label-free video microscopy in analog aquatic environments, PLOS ONE (2025). DOI: 10.1371/journal.pone.0318239

Comment by Dr. Krishna Kumari Challa on April 5, 2025 at 10:22am

Air pollution and extreme heat increase mortality in India

A new study from the Institute of Environmental Medicine, Karolinska Institutet reveals that days with both high air pollution and extreme heat substantially raise the risk of death in Indian cities more than either factor alone. The findings are published in the journal Environment International.

This study included daily counts of death from 10 major Indian cities between 2008 and 2019.

Researchers applied two advanced spatiotemporal models to estimate daily exposure levels of ambient air pollution and temperature. By analyzing approximately 3.6 million deaths, they found that the association between PM2.5 and mortality was particularly strong at high temperatures.

A 10 μg/m³ increase in fine particulate matter (PM2.5) was associated with a 4.6% rise in daily deaths on extremely hot days—substantially higher than the 0.8% increase observed on regular warm days. Similarly, the risk of death rose by 8.3% when temperatures shifted from warm to extremely hot at a pollution level of 20 μg/m³—but surged to 64% when PM2.5 reached 100 μg/m³. These results highlight a concerning synergy between heat and air pollution, showing that their combined effects on health are significantly more harmful than either factor alone.

The study emphasizes the need for integrated strategies to address both air pollution and climate change in India, where global warming is expected to further exacerbate the situation.

Jeroen de Bont et al, Synergistic associations of ambient air pollution and heat on daily mortality in India, Environment International (2025). DOI: 10.1016/j.envint.2025.109426

Comment by Dr. Krishna Kumari Challa on April 5, 2025 at 8:57am

Streptococcus pneumoniae, a bacteria known for causing serious diseases like pneumonia, blood infections, and meningitis, is surrounded by a capsule made up of polysaccharides, or sugar molecules that help the bacteria evade attacks by the body's immune system.

The PCV13 vaccine makes it easier for the immune system to attack S. pneumoniae and produce antibodies by linking the polysaccharide capsule layer to proteins. Exposure to neonatal antibiotics reduces antibody production against such polysaccharides, weakening the immune response.

Experiments on germ-free mice revealed that the lower immune response was linked to a reduced abundance of Bifidobacterium in the gut microbiome. However, giving the mice a mix of Bifidobacterium species or Infloran, a commonly used infant probiotic, helped reverse the negative effects of antibiotics and regain the immune response to PCV13.

The researchers propose that restoring a healthy Bifidobacterium-rich microbiota in antibiotic-exposed infants before their vaccination might enhance the antibody responses to vaccination, leading to better protection against infectious diseases.

David Lynn, Bifidobacteria support optimal infant vaccine responses, Nature (2025). DOI: 10.1038/s41586-025-08796-4. www.nature.com/articles/s41586-025-08796-4

Part 2

Comment by Dr. Krishna Kumari Challa on April 5, 2025 at 8:56am

Exposure to antibiotics as a newborn can impair immune response to vaccines, study finds

Immunization programs save millions of lives every year by protecting against preventable diseases. The immune response to vaccines, however, varies significantly between individuals, and the results can be suboptimal in populations at a higher risk of developing infectious diseases. Growing evidence suggests that differences in gut microbiota could be a key factor driving these variations.

A recent  study published in Nature found that babies treated with antibiotics within the first few weeks of their life showed weaker immune response to vaccines due to reduced levels of Bifidobacterium—a bacterial species that lives in the human gastrointestinal tract. Replenishing Bifidobacterium in the gut microbiome using probiotic supplements such as Infloran showed promising results in restoring the immune response.

The investigation revealed that children who were directly exposed to neonatal antibiotics, not the ones exposed to maternal antibiotics, produced much lower levels of antibodies against multiple polysaccharides included in the 13-valent pneumococcal conjugate vaccine or PCV13 vaccine.

Part 1

Comment by Dr. Krishna Kumari Challa on April 5, 2025 at 8:39am

Formation of haploid seeds was first noticed during experiments using a chemical phospholipase inhibitor on pollen. Researchers observed small, shriveled seeds and initially attributed them to the chemical's effects. Later trials showed the same seeds forming even in the complete absence of pollen, leading to the discovery of spontaneous parthenogenesis.

Genetic analysis confirmed the seeds were maternally derived and lacked paternal DNA. Parthenogenesis occurred across multiple sunflower lines, with some producing over 100 haploid seeds per flower head. High-intensity light significantly increased haploid yield, while blue or red light alone had no effect.

Maize pollen combined with boron improved haploid formation in certain genetic backgrounds. Germination trials showed a 40% success rate in soil.
Imaging showed that many haploid embryos which formed without fertilization had irregular shapes or multiple axis-like centers. Each seed still contained a single embryo, but some developed multiple shoot-like structures after germination. Tissue culture was used in regenerating healthy seedlings from these atypical forms.

Chromosome doubling produced fertile, seed-setting plants, with some individuals generating up to 188 seeds.

Unlike most flowering plants, sunflower embryos survived and germinated using nutrient reserves stored in the cotyledons, bypassing the usual requirement for endosperm development. This bypass of the endosperm requirement is highly unusual.

Discovery of parthenogenesis in sunflower introduces a previously unrecognized reproductive pathway in a major global crop. Researchers demonstrated that haploid seeds can develop without fertilization and be converted into fully fertile plants, offering a faster route to inbred line development.

Timothy Kelliher, Haploid facultative parthenogenesis in sunflower sexual reproduction, Nature (2025). DOI: 10.1038/s41586-025-08798-2. www.nature.com/articles/s41586-025-08798-2

Marco Todesco et al, Sunflower 'virgin births' enable accelerated crop breeding, Nature (2025). DOI: 10.1038/d41586-025-00904-8

Part 2

Comment by Dr. Krishna Kumari Challa on April 5, 2025 at 8:37am

Certain sunflower strains can be induced to form seeds without pollination

Biotechnologists have discovered that sunflowers can form viable haploid seeds through parthenogenesis in the absence of pollination. This discovery opens the possibility of a scalable doubled haploid system in sunflowers, a technique that could reduce the time needed to produce fully inbred lines from six years to 10 months.

Some animals, including certain birds, reptiles, fish, and crustaceans like Daphnia, can reproduce without fertilization through a process known as facultative parthenogenesis. In these species, females can produce offspring without male involvement. Charles Darwin first documented unusual reproductive patterns in plants.

In most flowering plants, seed formation depends on a process called double fertilization. This involves one sperm fertilizing the egg and another fertilizing a separate cell that forms the endosperm, a tissue that nourishes the embryo. Without fertilization, viable seeds rarely develop.

Sunflower is one of the world's most important oilseed crops, producing nearly 55 million metric tons globally in 2023. Because sunflower is a hybrid crop, improving its traits requires creating inbred parent lines, which typically takes six years through repeated self-pollination.

In the study, "Haploid facultative parthenogenesis in sunflower sexual reproduction," published in Nature, researchers examined how sunflowers can form haploid seeds without fertilization. The team conducted a combination of genetic, chemical, and environmental experiments to identify the factors that enable parthenogenesis and support a scalable doubled haploid breeding system.

Researchers tested sunflower plants under controlled greenhouse, growth chamber, and field conditions to identify genetic backgrounds capable of producing haploid seeds without fertilization.

Experiments included chemical treatments, manual and hormonal suppression of pollen, and variation in environmental factors such as light intensity and temperature. Flow cytometry and genetic analysis confirmed haploid seed formation. Tissue culture and chromosome doubling techniques were applied to regenerate fertile, doubled haploid plants.

Part 1

Comment by Dr. Krishna Kumari Challa on April 3, 2025 at 11:21am

This was the first study to demonstrate that a mother's exposure to phthalates can impact their baby's metabolome and also the first to show that these biological changes can impact newborn development. This is important because there is a common belief that the placenta protects the baby from a lot of harmful substances, but this study supports the fact that phthalates are able to cross through the placenta and actually impact the baby's biology before they are even born and negatively affect their development over time.
Once pregnant women are exposed to phthalates, these chemicals not only enter their body and disrupt maternal metabolism, but these exposures also impact the metabolism and neurobehavioral functioning of newborns.

And researchers found these substances stay with them in the body after they are born, as we did see some indication of a biological disruption occurring among the newborn babies that has a further impact on the neurodevelopment system.

Susan S. Hoffman et al. Impact of prenatal phthalate exposure on newborn metabolome and infant neurodevelopment, Nature Communications (2025). DOI: 10.1038/s41467-025-57273-z. www.nature.com/articles/s41467-025-57273-z

Part 2

Comment by Dr. Krishna Kumari Challa on April 3, 2025 at 11:19am

Using everyday products during pregnancy can affect newborns' metabolism, study shows

A newly published study by researchers found that a mother's exposure to phthalates during pregnancy can affect their newborn's metabolism and brain development.

Phthalates are a group of widely used plasticizers commonly found in a variety of cosmetics and personal care products, such as shampoos, soaps, and detergents, as well as plastic food and beverage containers. Previous research showed phthalates can affect hormones and suggested they may be linked to health effects in mothers and babies.

The study  published in Nature Communications this week was the first to explore and find evidence of how a pregnant woman's exposure to phthalates influences their baby's metabolism  at birth.

Main takeaways include:
Prenatal phthalate levels in the mother's blood during pregnancy were associated with lower levels of key neurotransmitter precursors (related to tyrosine and tryptophan metabolism) important for brain development in the newborn's blood soon after birth.
Higher prenatal phthalate levels were also associated with biological changes linked to lower information processing (or attention) and excitability (or arousal) scores in newborns.
These findings suggest that a mother's exposure to phthalates during pregnancy may influence her newborn's metabolism soon after birth. Furthermore, exposure to phthalates while babies are still in the uterus may also have lasting effects on infant brain development.

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