Comment

Comment by Dr. Krishna Kumari Challa on Saturday

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 Saturday

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 Saturday

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 Saturday

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 Saturday

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.

Part 1

Comment by Dr. Krishna Kumari Challa on April 3, 2025 at 11:14am

The heart remembers: Scientists describe how early-life cardiac injury in parents influences the next generation

Stress during the first years of life can have effects that last into adulthood. Less is known, however, about the possible inheritance of the consequences of early-life stress by the next generation. Now, scientists at the Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) and the University of Bern in Switzerland have discovered that heart injury early in life in one generation of mice triggers changes in cardiac function in their offspring. The study is published in the journal Circulation.

A family history of heart attack is known to influence an individual's risk of cardiovascular disease. Moreover, the risk for offspring is greater if a parent experienced a heart attack earlier in life. Nevertheless, it has remained unclear if heart injury in a parent directly influences the cardiovascular system of the next generation.

A large number of children require heart surgery every year in teh world, so exploring whether the "memory" of early-life cardiac injury can be transmitted to the next generation offers an important opportunity to increase our understanding of cardiovascular disease and to improve the collection of medical histories.

The new study  analyzed if experimentally induced cardiac injury in male mice could produce an inherited effect in the next generation. 

The results  show that the offspring of fathers with early-life cardiac injury had altered heart function. The offspring of injured fathers showed evidence of altered heart development, characterized by transient expansion of the left ventricle during the first weeks after birth. 

This is really surprising  since the only difference between the newborns was that in one group the father had experienced cardiac injury early in life, while in the other group the father was uninjured.

The offspring of injured fathers also showed alterations in their responses to cardiac injury. These changes included improvements in cardiac remodeling (changes in the size, shape, and function of the heart after induced injury) compared with the offspring of uninjured fathers. This superior cardiac remodeling was associated with an increased volume of blood ejected by the heart per minute.

After injury, the heart normally switches its energy source from lipids to glucose, and this results in an accumulation of lipids in the heart tissue. The offspring of injured fathers accumulated fewer lipids in response to induced heart injury and had higher concentrations of circulating lipids in the blood. These observations suggest that the metabolism of mice with this 'family history' recovers better when these mice are themselves subjected to cardiac injury.

The changes observed in the offspring of injured fathers indicate that cardiac surgery in the first weeks after birth leaves a lasting "memory" that can eventually be transmitted to the next generation.

The researchers conclude that the findings open the way to a better understanding of the impact of heart disorders and underline the potential value of including family surgical history when collecting patient medical histories.

Benedetta Coppe et al, Paternal Cardiac Lesion Induces Cardiac Adaptation in Offspring, Circulation (2025). DOI: 10.1161/CIRCULATIONAHA.124.070323

Comment by Dr. Krishna Kumari Challa on April 3, 2025 at 10:09am

 How heavy drinking damages cognition

For the first time, researchers demonstrate in an animal how heavy alcohol use leads to long-term behavioral issues by damaging brain circuits critical for decision-making.

Rats exposed to high amounts of alcohol exhibited poor decision-making during a complex task, even after a months-long withdrawal period. Key areas of their brains had undergone dramatic functional changes compared to healthy rats.

The findings, published in Science Advances, provide a new explanation of alcohol's long-term effects on cognition.

We now have a new model for the unfortunate cognitive changes that humans with alcohol-use disorder show, say the researchers.

We know that humans who are addicted to alcohol can show deficits in learning and decision-making that may contribute to their poor decisions related to alcohol use. We needed an animal model to better understand how chronic alcohol abuse affects the brain. Knowing what is happening in the brain of an animal when they are having these decision-making difficulties will tell us what is happening in humans.

In their experiments, the researchers found that the rats exposed to drinking did very badly when compared to controls.

The team linked the behavioral difficulties to dramatic functional transformations in the dorsomedial striatum, a part of the brain critical for decision-making. The alcohol had damaged neural circuits, causing alcohol-exposed rats to process information less effectively.

One surprise was how long alcohol dependence impairs cognition and neural function, even after withdrawal.

This may give us insight into why relapse rates for people addicted to alcohol are so high. Alcohol-induced neural deficits may contribute to decisions to drink even after going to rehab. We can clearly demonstrate these deficits can be long-lasting.

Chronic Ethanol Exposure Produces Sex-Dependent Impairments in Value Computations in the Striatum, Science Advances (2025). DOI: 10.1126/sciadv.adt0200

Comment by Dr. Krishna Kumari Challa on April 3, 2025 at 9:44am

Flowerpot snake's DNA repair ability provides insights into human genetic conditions like Down syndrome

The flowerpot snake, one of the world's smallest snakes, has some unusual distinctions. Also known as the Brahminy blind snake, it's the only known snake species with three sets of chromosomes instead of two—and it can reproduce without a mate.

By analyzing the flowerpot snake's unique genome, scientists are uncovering how the tiny reptile repairs its DNA and prevents harmful mutations. The findings, published in the journal Science Advances, provide valuable insights into genetic repair mechanisms that could deepen our understanding of human gene evolution.

This DNA repair and replication activity supports a fascinating mechanism called premeiotic endoreplication, a process through which the snake duplicates its chromosomes before dividing them, sidestepping the need for the typical pairing of chromosomes seen in sexual reproduction. This mechanism allows the snake to produce offspring that are exact genetic clones of itself.

The flowerpot snake's genetic and reproductive quirks may also provide insights into human trisomy conditions, such as Down syndrome.

For example, we know that having multiple sets of chromosomes is rare for animals, yet flowerpot snakes survive just fine with three instead of the normal two humans have.

Using advanced genomic technology, the research team discovered that the flowerpot snake, native to Africa and Asia, has 40 chromosomes, organized into three subgenomes. These subgenomes formed through complex genetic events, including chromosome fusion in ancestral species. The researchers hypothesize that this genetic structure enables the snake to reproduce without needing sperm from a male partner.

One major question the scientists explored was whether this reproductive strategy comes with evolutionary drawbacks. Asexual species typically struggle because they lack genetic shuffling, which helps eliminate harmful mutations over time. However, the flowerpot snake appears to have developed a way to counteract this risk. The researchers think its slow but steady evolutionary pace helps limit the accumulation of harmful mutations.

They also examined how genetic variations across different flowerpot snake populations suggest chromosome exchanges between the subgenomes. These exchanges appear to balance genetic diversity and stability—maintaining enough variation for adaptation while preventing incompatibilities that could disrupt reproduction.

The study also revealed something unexpected—many of the flowerpot snake's immune-related and sexually selected genes, such as those involved in sperm development, have lost their functions.

Yunyun Lv et al, Genomic Insights into Evolution of Parthenogenesis and Triploidy in the Flowerpot Snake, Science Advances (2025). DOI: 10.1126/sciadv.adt6477. www.science.org/doi/10.1126/sciadv.adt6477

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