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Comment by Dr. Krishna Kumari Challa on October 4, 2025 at 8:55am

Trauma in a puppy's first six months linked to adult aggression, says new study

As many dog owners can attest, their four-legged companions are delightful and loving. But for others, their animals have an aggressive side, such as biting and attacking strangers, which may ultimately lead to them having to be euthanized. But why do some dogs turn out this way?

According to a new study of 211 dog breeds published in the journal Scientific Reports, adverse experiences such as abuse or being given up during a dog's first six months of life mean they are more likely to be fearful and aggressive as adults.

To explore this link between early life experiences and adult behavior, scientists conducted a large-scale survey of 4,497 dog owners. Each owner filled out a detailed questionnaire about their canine companion, including its complete life history, breed and current living environment. They were also asked about any adversity their pet experienced during its first six months.

Additionally, owners completed a standard behavior test (C-BARQ) to rate their dog's current fear and aggression levels. The scientists then used powerful statistical tools to determine whether early trauma, breed, or a combination of the two was most responsible for a dog's behaviour.

Just like in humans, the first few months of life are crucial for emotional development. The research team found that dogs that experienced any kind of adversity in the first six months were more likely to be aggressive as adults, regardless of age or sex or whether the animal was neutered. Both genes and environment are involved, as indicated by the fact that the effect of adversity differed across different breeds.

For example, some breeds, such as Siberian Huskies, American Eskimo Dogs, and American Leopard Hounds, as well as pit-bull type dogs, were more likely to become aggressive or fearful after experiencing early trauma. Meanwhile, other breeds, such as the Labrador Retriever, were a lot more resilient. Even when they experienced trauma, the chances of them being aggressive adults were relatively low.

Overall, the study clearly demonstrates that a dog's early life is crucial and highlights the importance of responsible breeding and proper pet care.

Julia Espinosa et al, Influence of early life adversity and breed on aggression and fear in dogs, Scientific Reports (2025). DOI: 10.1038/s41598-025-18226-0

Comment by Dr. Krishna Kumari Challa on October 3, 2025 at 9:49am

Do stranded dolphins have Alzheimer's disease?

One of the most heartbreaking occurrences for nature lovers is to discover a beached marine mammal such as a dolphin or whale. If the animal is still alive, marine biologists assisted by citizen volunteers try to protect the beached marine mammal from sun exposure and skin desiccation by pouring buckets of sea water on them and sometimes covering them with wet blankets. Other volunteers try to find ways to help the animal return to their native ocean habitat when the tide rises.

Unfortunately, some beached marine mammals are discovered after they have died. Such unsettling events give rise to a broader question: why do dolphins and whales become stranded on shore in the first place?

A group of scientists  have come up with an unusual hypothesis: just as some adult humans with dementia are occasionally found wandering far from their homes, perhaps dolphins become similarly disoriented by suffering from a form of Alzheimer's disease. The research was published in Communication Biology.

In the case of marine mammals, it appears that Alzheimer's-type neuropathology and disorientation may result from chronic exposure to toxic molecules produced by cyanobacteria.

Studies of villagers on the island of Guam show that chronic dietary exposure to cyanobacterial toxins are associated with misfolded tau proteins and amyloid plaques characteristic of Alzheimer's disease.

The cyanobacterial toxin β-N-methylamino-L-alanine (BMAA), as well as its isomers 2,4-diaminobutyric acid (2,4-DAB), and N-2-aminoethylglycine (AEG), have been found to be extremely toxic to neurons. BMAA triggers Alzheimer's-like neuropathology and cognitive loss in experimental animals. These toxins can be biomagnified up the food chain in the marine ecosystem.

A study of 20 common bottlenose dolphins stranded in the Indian River Lagoon in eastern Florida showed that their brains contained BMAA and its isomers, particularly 2,4-DAB.

Dolphins stranded during the summer cyanobacterial bloom season contained 2,900 times the concentration of 2,4-DAB than those from non-bloom seasons. Brain neuropathology similar to Alzheimer's patients, including β-amyloid plaques and hyperphosphorylated tau proteins were found in the dolphin brains.

In addition, TDP-43 protein inclusions characteristic of a particularly severe form of Alzheimer's were also found in the dolphin brains. During bloom seasons, the same dolphins showed 536 differentially expressed genes associated with Alzheimer's disease.

The duration of cyanobacterial blooms is increasing with climate warming and nutrient inputs associated with agricultural runoff and sewage discharges.

What is worse is scientists found that even among Guam villagers, exposure to cyanobacterial toxins appeared to trigger neurological diseases.

Wendy Noke Durden et al, Alzheimer's disease signatures in the brain transcriptome of Estuarine Dolphins, Communications Biology (2025). DOI: 10.1038/s42003-025-08796-0

Comment by Dr. Krishna Kumari Challa on October 3, 2025 at 9:38am

Ancient viral DNA is essential for human embryo development, study shows

Our ancient past isn't always buried history. When it comes to our DNA, nearly 9% of the human genome is made up of leftover genetic material from ancient viruses (called endogenous retroviruses or ERVs) that infected our ancestors millions of years ago and became permanently integrated into our genetic code. In a new study published in the journal Nature, scientists have demonstrated that one piece of this viral junk is essential for the earliest stages of human life.

Knowledge of how ERVs affect human development is limited because scientists obviously cannot conduct ethical experiments on embryos. To overcome this, researchers in this study used human blastoids, 3D models grown from stem cells that mimic the structure and key cell types of a natural blastocyst. This is the ball of cells that form in early pregnancy, about five to seven days after fertilization.

The research team focused on a specific type of ERV known as HERVK LTR5Hs, which were introduced into our DNA after our lineage split from Old World monkeys. Although this event occurred millions of years ago, it is considered relatively recent in evolutionary genetic terms.
To determine the functional effect of these viral remnants on the early embryo, the research team used cutting-edge genetic tools that act like molecular scissors to switch off LTR5Hs elements or delete them completely. The results were dramatic. The blastoids either died or turned into disorganized clumps. This provided clear proof that this ancient DNA is essential for the pre-implantation stage of human development.

The researchers also dug deeper to find out what was going on at the subcellular level. They discovered that the LTR5Hs elements act as powerful enhancers, boosting the activity of neighboring genes. When their activity is suppressed, many nearby genes associated with the epiblast (the cell layer that eventually forms the embryo) are turned down. That is, their activity is reduced. This showed that the viral DNA is directly responsible for controlling these essential early developmental instructions.

One of the most important discoveries involved the ZNF729 gene. The team found that one specific LTR5Hs insertion (an extra piece of DNA added to a DNA sequence), unique to humans, acts as a master key for activating this gene. Since the gene regulates fundamental cellular processes, such as cell growth and metabolism, the viral DNA master key is crucial to our development.

Raquel Fueyo et al, A human-specific regulatory mechanism revealed in a pre-implantation model, Nature (2025). DOI: 10.1038/s41586-025-09571-1

Comment by Dr. Krishna Kumari Challa on October 3, 2025 at 9:14am

The colonies didn't seem to wake up that much faster at hotter temperatures. The results could hold lessons for thawing permafrost in the real world: After a hot spell, it may take several months for microbes to become active enough that they begin to emit greenhouse gases into the air in large volumes.

In other words, the longer Arctic summers grow, the greater the risks for the planet.

T. A. Caro et al, Microbial Resuscitation and Growth Rates in Deep Permafrost: Lipid Stable Isotope Probing Results From the Permafrost Research Tunnel in Fox, Alaska, Journal of Geophysical Research: Biogeosciences (2025). DOI: 10.1029/2025jg008759

Part 2

Comment by Dr. Krishna Kumari Challa on October 3, 2025 at 9:13am

Microbes trapped in permafrost awake after thousands of years

In a new study, a team of geologists and biologists  resurrected ancient microbes that had been trapped in ice—in some cases for around 40,000 years.

The study is a showcase of the planet's permafrost. That's the name for a frozen mix of soil, ice and rocks that underlies nearly a quarter of the land in the northern hemisphere. It's an icy graveyard where animal and plant remains, alongside plentiful bacteria and other microorganisms, have become stuck in time.

That is, until curious scientists try to wake them up.

The group discovered that if you thaw out permafrost, the microbes within will take a while to become active. But after a few months, like waking up after a long nap, they begin to form flourishing colonies.

The research has wide implications for the health of the Arctic, and the entire planet.

Today, the world's permafrost is thawing at an alarming rate because of human-caused climate change. Scientists worry this trend could kick off a vicious cycle. As permafrost thaws, microbes living in the soil will begin to break down organic matter, spewing it into the air as carbon dioxide and methane—both potent greenhouse gases.

It's one of the biggest unknowns in climate responses. How will the thawing of all this frozen ground, where we know there's tons of carbon stored, affect the ecology of these regions and the rate of climate change?

In the current study, the researchers collected samples of permafrost that was a few thousand to tens of thousands of years old from the walls of the tunnel. They then added water to the samples and incubated them at temperatures of 39 and 54 degrees Fahrenheit—chilly for humans, but downright boiling for the Arctic.

The researchers relied on water made up of unusually heavy hydrogen atoms, also known as deuterium. That allowed them to track how their microbes drank up the water, then used the hydrogen to build the membranes made of fatty material that surround all living cells.

What they saw was surprising.
In the first few months, these colonies grew at a creep, in some cases replacing only about one in every 100,000 cells per day. In the lab, most bacterial colonies can completely turn over in the span of a few hours.

But by the six-month mark, that had all changed. Some bacterial colonies even produced gooey structures called "biofilms" that you can see with the naked eye.
These microbes likely couldn't infect people, but the team kept them in sealed chambers regardless.

Part 1

Comment by Dr. Krishna Kumari Challa on October 3, 2025 at 8:56am

Bird decorations

Bearded Vulture nests found to have hoards of cultural artifacts—some up to 650 years old

Many people have probably seen birds picking up small pieces of man-made materials, like strips of a plastic bag or paper litter, and taking them into their nest. This behavior appears to be fairly widespread among birds. What's unique about some larger bird species, like certain vultures, eagles, and falcons, is that the same nest is used for centuries if it continues to be in a safe space. Generations of birds will continue to occupy and add materials to these nests for hundreds of years.

These behaviors are well documented in the Bearded Vulture (Gypaetus barbatus), a threatened species that builds nests in cliff caves, rock shelters, or on cornices. The Bearded Vulture can most often be found in European mountain ranges, particularly the Pyrenees. The environment in many of these regions is dry, particularly in the cave-like structures where nests are found, creating an ideal environment for long-term preservation.

Over a decade ago, a group of researchers  had the opportunity to examine 12 of these nests in detail. Their study was recently published in the journal Ecology and discusses a number of surprising findings.

The team rifled through centuries worth of vulture eggshells, remains of prey, and nesting material and among these they also found 226 items that had been made or altered by humans—providing a window into both past ecosystems and human cultures from the region. The hoard included items like a slingshot made from esparto grass, shoes, a crossbow bolt, a decorated piece of sheep leather and a wooden lance.

Even more surprising was that several items were well over 600 years old, according to carbon-14 dating. Results from one shoe dated back to around 675 years ago, while the decorated leather dated to around 650 years ago. However, the dating revealed a range of time periods, with a piece of basket dating to about 150 years ago.

Thanks to the solidity of Bearded Vulture nest structures and their locations in the western Mediterranean, generally in protected places such as caves and rock shelters with relatively stable temperature and low humidity conditions, they have acted as natural museums, conserving historical material in good condition," the authors write.

In addition to the human-made items, the researchers found 2,117 bones, 86 hooves, 72 leather remains, 11 hair remains and 43 eggshells. The team notes that this study and its findings "can provide information about temporal
changes in the trophic spectrum, past environment, and the wild and domestic species present."

They also call these nests a powerful tool for investigating and understanding more about the ecology, biodiversity trends, and environmental changes that the vultures are subject to. The findings could potentially inform habitat restoration and species reintroduction efforts.

Antoni Margalida et al, The Bearded Vulture as an accumulator of historical remains: Insights for future ecological and biocultural studies, Ecology (2025). DOI: 10.1002/ecy.70191

Comment by Dr. Krishna Kumari Challa on October 2, 2025 at 11:56am

Mitosis, meiosis, or a new different option
Researchers have found a way to prompt a new cell division process to create a viable egg cell from a skin cell. First, they implanted the skin cell’s nucleus into an empty egg. Then, the team induced a process they called ‘mitomeiosis’. This forces the egg to discard one set of chromosomes, which are replaced by that of the sperm during fertilization. Only a few of the resulting embryos developed beyond eight cells, but the research demonstrates the potential of the process for in-vitro fertilization using skin cells, the researchers say.

https://www.reuters.com/business/healthcare-pharmaceuticals/scienti...

Reference: https://www.nature.com/articles/s41467-025-63454-7?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on October 2, 2025 at 11:23am

Overall, first responders with elevated CH mutations were nearly six times likelier to develop leukemia than those without the mutations. Exposure of mice to WTC dust led to high levels of inflammatory markers and an increase in mutant cells, suggesting that toxin-induced inflammation plays a key role in propagating the blood cells.

In addition, researchers found that younger first responders (those under age 60) with elevated CH possessed a set of gene mutations quite distinct from the classic mutations associated with age-related CH—indicating that the gene-altering toxins in WTC dust may contribute to cancer risk by accelerating the aging process.
To learn how exposure to toxins is associated with CH mutations and increased leukemia risk, the researchers tested the dust collected from the WTC site in a mouse model.

The dust caused an inflammatory response traced to the protein IL1RAP; the high levels of IL1RAP were associated with increased numbers of defective blood-forming stem cells—mimicking the high CH levels observed in the first responders. Importantly, the researchers found they could prevent the rise in defective mutant cells by knocking out the gene that codes for IL1RAP.
IL1RAP has been implicated in many types of cancer as well as in inflammatory and autoimmune diseases and that several drugs aimed at inhibiting the protein are being evaluated in clinical trials.
By screening toxin-exposed populations for CH, we could identify people at risk for blood cancers and then potentially treat or even prevent those cancers by targeting IL1RAP, say the researchers.

Elevated clonal hematopoiesis in environmentally exposed 9/11 first responders has distinct age-related patterns and relies on IL1RAP for clonal expansion, Cancer Discovery (2025).

https://www.eurekalert.org/news-releases/1100191

Part 2

Comment by Dr. Krishna Kumari Challa on October 2, 2025 at 11:20am

9/11 study shows how toxic exposures may lead to blood cancers

A study by researchers has found that mutations in blood-forming cells may explain the increased risk for leukemia and other blood disorders among first responders exposed to the 9/11 World Trade Center (WTC) disaster site and its toxic dust.

The study also points to a novel strategy for use against inflammation and blood disorders associated with environmental toxins. The research is published in Cancer Discovery in a study titled "Elevated clonal hematopoiesis in environmentally exposed 9/11 first responders has distinct age-related patterns and relies on IL1RAP for clonal expansion."

The findings provide new insights into the long-term health impacts of environmental catastrophes, such as wildfires, and suggest targeted interventions for those affected by 9/11 or similar disasters.

The collapse of the WTC produced tremendous quantities of airborne particulate matter—a potent mixture of carcinogens and genetically toxic substances to which an estimated 400,000 responders, area workers, and residents were exposed.

In previous studies, researchers noted a higher incidence of cancers, cardiovascular disease, and other health problems among 9/11 first responders compared with the general population. However, few studies have examined how such environmental exposures can lead to blood cancers.

For this study,  scientists sequenced blood samples from nearly 1,000 first responders who were exposed to the WTC site, along with blood from two control groups: 255 firefighters who were not at the WTC and 198 unexposed people in the general population.
All samples were collected between December 2013 and October 2015. The toxic 9/11 dust cloud was found to be associated with mutations in the blood cells of many responders.

Compared with control-group individuals, WTC-exposed first responders had a significantly higher prevalence of clonal hematopoiesis (CH)—a condition in which a group, or clone, of a person's blood-forming (hematopoietic) stem cells contain the same gene mutations. Typically associated with aging, CH is a precancerous condition known to increase the risk of blood cancer and inflammation.

Part 1

Comment by Dr. Krishna Kumari Challa on October 2, 2025 at 11:04am

Rare fossil reveals ancient leeches weren't bloodsuckers

A newly described fossil reveals that leeches are at least 200 million years older than scientists previously thought, and that their earliest ancestors may have feasted not on blood, but on smaller marine creatures.

Roughly 430 million years old, the fossil includes a large tail sucker—a feature still found in modern leeches—along with a segmented, teardrop-shaped body. But one important feature isn't found in this fossil: the forward sucker that many of today's leeches use to pierce skin and draw blood.

This absence, along with the fossil's marine origin, suggests a very different early lifestyle for the group known as Hirudinida. Rather than sucking blood from mammals, reptiles, and other vertebrates, the earliest leeches may have roamed the oceans, consuming soft-bodied invertebrates whole or feeding on their internal fluids.

Blood feeding takes a lot of specialized machinery. Anticoagulants, mouthparts, and digestive enzymes are complex adaptations. It makes more sense that early leeches were swallowing prey whole or maybe drinking the internal fluids of small, soft-bodied marine animals.

Previously, scientists thought leeches emerged about 150–200 million years ago. That timeline has now been pushed back by at least 200 million years, thanks to the fossil found in the Waukesha biota, a geological formation in Wisconsin known for preserving the bodies of soft tissue animals that usually decay before fossilization.

Preserving a leech fossil is no small feat. Leeches lack bones, shells, or exoskeletons that are most easily preserved over millions of years. Fossils like this require exceptional circumstances to preserve, often involving near-immediate burial, a low-oxygen environment, and unusual geochemical conditions.

A rare animal and just the right environment to fossilize it—it's like hitting the lottery twice.

de Carle D, et al. The first leech body fossil predates estimated hirudinidan origins by 200 million years, PeerJ (2025). doi.org/10.7717/peerj.19962

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