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Comment by Dr. Krishna Kumari Challa on June 26, 2025 at 9:52am

Nitrate in drinking water linked to preterm birth rates

Even low levels of nitrate—a common agricultural runoff and drinking water contaminant—are associated with increased risks of preterm birth and low birthweight babies, according to a study published in PLOS Water.

Nitrate is a naturally occurring compound increasingly found in inorganic fertilizers and, through runoff, in groundwater. When consumed by humans, nitrates can interfere with the blood's capacity to carry oxygen.

After controlling for maternal and paternal characteristics as well as seasonal variation, the study found that early prenatal exposure to greater than 0.1 mg/L nitrate—just 1% of the current EPA limit—was associated with an increase in preterm birth (Est.=+0.66%-points; C.I.=0.31, 1.01) and early prenatal exposure to greater than 5 mg/L nitrate was associated with an increased risk of low birth weight babies (Est.=+0.33%-points; C.I.=0.03, 0.63). There were no additional risks conferred by exposure to elevated levels of nitrate, above 10 mg/L.

PLOS Water (2025). DOI: 10.1371/journal.pwat.0000329

Comment by Dr. Krishna Kumari Challa on June 26, 2025 at 9:37am

Why most cats prefer to sleep on their left side?

An international research team that analyzed several hundred YouTube videos of sleeping cats found that they prefer to sleep on their left side. The researchers see this bias as an evolutionary advantage because it favors hunting and escape behavior after waking up.

All animals are particularly vulnerable while sleeping. Cats sleep around 12 to 16 hours a day, preferably in elevated places where their predators can only access them from below.

Researchers analyzed 408 publicly available YouTube videos in which a single cat was clearly visible with its entire body sleeping on one side for at least 10 seconds.

Two-thirds of the videos showed cats sleeping on their left side.

The explanation: Cats that sleep on their left side perceive their surroundings upon awakening with their left visual field, which is processed in the right hemisphere of the brain. This hemisphere is specialized in spatial awareness, the processing of threats and the coordination of rapid escape movements. If a cat sleeps on its left shoulder and wakes up, visual information about predators or prey goes directly to the right hemisphere of the brain, which is best in processing them. "Sleeping on the left side can therefore be a survival strategy," the researchers conclude.

Sevim Isparta et al, Lateralized sleeping positions in domestic cats, Current Biology (2025). DOI: 10.1016/j.cub.2025.04.043

Comment by Dr. Krishna Kumari Challa on June 26, 2025 at 9:00am

Scientists detect deep Earth pulses beneath Africa

Research led by Earth scientists has uncovered evidence of rhythmic surges of molten mantle rock rising from deep within the Earth beneath Africa. These pulses are gradually tearing the continent apart and forming a new ocean.

The findings, published in Nature Geoscience, reveal that the Afar region in Ethiopia is underlain by a plume of hot mantle that pulses upward like a beating heart.

The team's discovery reveals how the upward flow of hot material from the deep mantle is strongly influenced by the tectonic plates—the massive solid slabs of Earth's crust—that ride above it.

Over millions of years, as tectonic plates are pulled apart at rift zones like Afar, they stretch and thin—almost like soft plasticine—until they rupture. This rupturing marks the birth of a new ocean basin.

 Mantle upwelling at Afar triple junction shaped by overriding plate dynamics, Nature Geoscience (2025). DOI: 10.1038/s41561-025-01717-0

Comment by Dr. Krishna Kumari Challa on June 26, 2025 at 8:51am

Scientists discover unknown organelle inside our cells

The discovery of an unknown organelle inside our cells could open the door to new treatments for devastating inherited diseases.

The organelle, a type of specialized structure, has been dubbed a "hemifusome" by its discoverers. This little organelle has a big job helping our cells sort, recycle and discard important cargo within themselves, the scientists say. The new discovery could help scientists better understand what goes wrong in genetic conditions that disrupt these essential housekeeping functions.

Researchers think the hemifusome helps manage how cells package and process material, and when this goes wrong, it may contribute to diseases that affect many systems in the body.

 Amirrasoul Tavakoli et al, Hemifusomes and interacting proteolipid nanodroplets mediate multi-vesicular body formation, Nature Communications (2025). DOI: 10.1038/s41467-025-59887-9

 

Comment by Dr. Krishna Kumari Challa on June 25, 2025 at 11:22am

Droughts can reduce the caloric value of flower nectar by up to 95%

A study indicates that projected droughts by the end of this century could reduce the caloric value of flower nectar by up to 95%. This would harm pollinators, such as bees, as well as plants that depend on cross-pollination to reproduce and bear fruit, such as zucchini (Cucurbita pepo). In a less drastic scenario with a 30% reduction in rainfall, the drop was 34%.

In terms of calories potentially lost in the nectar, this is equivalent to more than a ton of sugar per hectare, from 1,325 to 71 kilos. Without nectar to consume, the bees leave, the plants don't reproduce, and the farmers lose production.

The work showed that an increase in rainfall positively affected an increase in nectar calories by 74%. However, the researchers point out the problems of heavier rainfall events in a wider ecological context.

A high frequency and intensity of rainfall can have devastating consequences for plants, flower visitors such as birds and insects, and the maintenance of interactions between plants and pollinators.

For example, the researchers cite the decrease in pollinator activity during rainy periods. Heavy rains make it difficult for pollinators to fly and regulate their body temperature, so they require more energy to search for food. Additionally, increased erosion and loss of nutrients affect crops.

Maria Luisa P. Frigero et al, Extreme events induced by climate change alter nectar offer to pollinators in cross pollination-dependent crops, Scientific Reports (2025). DOI: 10.1038/s41598-025-94565-2

Comment by Dr. Krishna Kumari Challa on June 25, 2025 at 11:16am

Sharks freeze when you turn them upside down

The freeze response—called "tonic immobility"—can be a lifesaver. Possums famously "play dead" to avoid predators. So do rabbits, lizards, snakes, and even some insects.

But what happens when a shark does it?

Researchers explored this strange behavior in sharks, rays and their relatives. In this group, tonic immobility is triggered when the animal is turned upside down—it stops moving, its muscles relax, and it enters a trance-like state. Some scientists even use tonic immobility as a technique to safely handle certain shark species. 

The reasons behind tonic immobility remain murky—especially in the ocean. It is generally thought of as an anti-predator defense. 

Three main hypotheses try to explain this immobility in sharks:

Anti-predator strategy—"playing dead" to avoid being eaten

Reproductive role—some male sharks invert females during mating, so perhaps tonic immobility helps reduce struggle

Sensory overload response—a kind of shutdown during extreme stimulation.

But research results don't support any of these explanations.

 So, scientists offer a simpler explanation. Tonic immobility in sharks is likely an evolutionary relic.

Evolutionary analysis suggests tonic immobility is "plesiomorphic"—an ancestral trait that was likely present in ancient sharks, rays and chimeras. But as species evolved, many lost the behavior.

Whatever may be the reason if you want to handle the sharks safely, just turn them upside down!

 Joel H. Gayford et al, Tonic immobility in cartilaginous fishes (Chondrichthyes): function, evolutionary history, and future directions, Reviews in Fish Biology and Fisheries (2025). DOI: 10.1007/s11160-025-09958-3

Comment by Dr. Krishna Kumari Challa on June 25, 2025 at 11:06am

Scientists use gene editing to correct harmful mitochondrial mutations in human cells

In a step toward treating mitochondrial diseases, researchers  have successfully edited harmful mutations in mitochondrial DNA using a genetic tool known as a base editor. The results, published in the open-access journal PLOS Biology, offer new hope for people with rare genetic conditions.

Mitochondria have their own small set of DNA. Mutations in this mitochondrial DNA can lead to a wide range of maternally inherited diseases, cancer, and aging-related conditions. While the development of CRISPR technology has given scientists new ways to correct mutations in nuclear DNA, this system cannot effectively cross the mitochondrial membrane and reach mitochondrial DNA.

In the new study, the researchers used a tool called a base editor—specifically, a DdCBE (double-stranded DNA deaminase toxin A-derived cytosine bas editor). This tool allows scientists to change a single letter in the DNA code without cutting it, and it works on mitochondrial DNA.

The team showed that they could effectively generate and correct mitochondrial DNA mutations in multiple disease-linked cell types in the lab. First, they engineered liver cells to carry a mitochondrial mutation that impairs energy production. Then they showed they could fix a different mutation in skin cells taken from a patient with the mitochondrial disorder Gitelman-like syndrome, restoring key signs of healthy mitochondrial function.

To help move the therapy toward clinical use, the researchers also tested the efficacy of delivering the mitochondrial base editors in mRNA form, rather than as DNA, and within lipid nanoparticles for delivery.

They showed that these approaches are more efficient and less toxic to cells than older methods like DNA plasmids. Importantly, the edits were highly specific, with minimal off-target changes detected in nuclear DNA and multiple detected in mitochondrial DNA.

Joore IP, et al. Correction of pathogenic mitochondrial DNA in patient-derived disease models using mitochondrial base editors. PLOS Biology (2025). DOI: 10.1371/journal.pbio.3003207

Comment by Dr. Krishna Kumari Challa on June 25, 2025 at 10:56am

Why AI and humans see objects differently: Meaning versus visual features

While humans concentrate on the meaning of objects, artificial intelligence focuses on visual characteristics.

These dimensions represent various properties of objects, ranging from purely visual aspects, like 'round' or 'white,' to more semantic properties, like 'animal-related' or 'fire-related,' with many dimensions containing both visual and semantic elements.

 While humans primarily focus on dimensions related to meaning—what an object is and what we know about it—AI models rely more heavily on dimensions capturing visual properties, such as the object's shape or color. Researchers call this phenomenon 'visual bias' in AI.

"Even when AI appears to recognize objects just as humans do, it often uses fundamentally different strategies. This difference matters because it means that AI systems, despite behaving similarly to humans, might think and make decisions in entirely different ways, affecting how much we can trust them.

 Florian P. Mahner et al, Dimensions underlying the representational alignment of deep neural networks with humans, Nature Machine Intelligence (2025). DOI: 10.1038/s42256-025-01041-7

Comment by Dr. Krishna Kumari Challa on June 25, 2025 at 9:42am

New evidence map shows normal use of plastic packaging contaminates food with micro- and nanoplastics

In an article published in npj Science of Food, scientists led by the Food Packaging Forum show that the normal and intended use of plastic food packaging and other food contact articles (FCAs), such as opening a plastic bottle or chopping on a plastic cutting board, can contaminate foodstuffs with micro- and nanoplastics (MNPs).

The article describes how the authors systematically evaluated 103 previously published studies investigating plastic particles less than 10 mm in foodstuffs or food simulants that had been in contact with an FCA made partly or entirely of plastic.

Food contact articles are a relevant source of MNPs in foodstuffs; however, their contribution to human MNP exposure is underappreciated, the researchers say.

 Food contact articles as source of micro- and nanoplastics: a systematic evidence map, npj Science of Food (2025). DOI: 10.1038/s41538-025-00470-3

Comment by Dr. Krishna Kumari Challa on June 25, 2025 at 9:38am

500 bird species face extinction within the next century, researchers warn

Climate change and habitat loss could cause more than 500 bird species to go extinct in the next 100 years, researchers  have found.

Their study, published in Nature Ecology & Evolution, reveals this number is three times higher than all bird extinctions recorded since 1500 CE. The extinction of vulnerable birds such as the bare-necked umbrellabird, the helmeted hornbill, and the yellow-bellied sunbird-asity would greatly reduce the variety of bird shapes and sizes worldwide, harming ecosystems that depend on unique birds like these for vital functions.

The scientists found that even with complete protection from human-caused threats like habitat loss, hunting and climate change, about 250 bird species could still die out.

Many birds are already so threatened that reducing human impacts alone won't save them. These species need special recovery programs, like breeding projects and habitat restoration, to survive.

We face a bird extinction crisis unprecedented in modern times. We need immediate action to reduce human threats across habitats and targeted rescue programs for the most unique and endangered species, the researchers say.

The researchers examined nearly 10,000 bird species using data from the IUCN Red List. They predicted extinction risk based on the threats each species faces. The study found that large-bodied birds are more vulnerable to hunting and climate change, while birds with broad wings suffer more from habitat loss.

This research also identified which conservation actions will best preserve both the number of bird species and their ecological functions.

Stopping the destruction of habitats would save the most birds overall. However, reducing hunting and preventing accidental deaths would save birds with more unusual features, which are especially important for ecosystem health.

Threat reduction must be coupled with targeted recovery programmes to conserve global bird diversity, Nature Ecology & Evolution (2025). DOI: 10.1038/s41559-025-02746-z

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