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Comment by Dr. Krishna Kumari Challa 13 minutes ago

Selfish sperm hijack Overdrive gene to kill healthy rivals

A new study has discovered the mechanism behind a decades-old evolutionary mystery—how "selfish chromosomes" cheat the rules of genetic inheritance. The researchers found that rogue chromosomes hijack the Overdrive (Ovd) gene to destroy rival sperm.
Selfish chromosomes exploit the Overdrive (Ovd) gene, which normally eliminates abnormal sperm, to destroy healthy rival sperm and increase their own transmission. This mechanism underlies segregation distortion, where inheritance deviates from Mendelian ratios. The phenomenon was observed in two Drosophila species, suggesting independent evolution of similar strategies. Ovd is not essential for fertility but acts as a quality control checkpoint.
The study is the first to identify that the Ovd gene acts as a quality control checkpoint during sperm development. Normally, Ovd detects and eliminates abnormal sperm cells. But selfish chromosomes exploit the system to kill competitors, boosting their chances of passing into the next generation.

The findings, published in Nature Communications, reveal the biology behind segregation distortion, a phenomenon in which genes sway inheritance in their favor to beat the standard 50/50 odds predicted by Mendelian genetics. The team observed the scheme in two Drosophila species, each carrying completely different selfish chromosomes, which suggests that multiple genetic systems may evolve independently to exploit the same Ovd pathway.
Scientists first discovered segregation distortion in the 1920s while studying the fruit fly Drosophila obscura. Since then, the phenomenon has been found across the animal kingdom, from nematodes to mammals.
While humans lack an exact genetic equivalent, a similar quality-control process may exist that uses different machinery. The findings could offer new insights into male infertility and the evolution of reproductive barriers between species.

Jackson T. Ridges et al, Selfish chromosomes exploit a germline checkpoint to eliminate competing gametes, Nature Communications (2026). DOI: 10.1038/s41467-025-68254-7

Comment by Dr. Krishna Kumari Challa 32 minutes ago

Forensic Science: Corpses leave clues behind in the soil long after they're gone

It is not uncommon for a body to be moved after a murder, usually to hide or eliminate evidence. And while a desert may seem like the perfect place to commit such a crime, a new study shows that a cadaver can still leave critical clues behind in that harsh environment. The study is published in the Journal of Forensic Sciences.

Researchers have found that trace elements linger at an original dump site even after an extensive amount of time. These elements can provide insights into postmortem processes, helping forensic investigators uncover clandestine burials and relocate the remains of murder victims.

A lot of times a murderer will kill someone and put the body somewhere, stash it, panic and then move it. And how can you ever trace where they have done this?

The surprising result was that even with a hot  summer, researchers could still tell that there had been something that was dying and decomposing in that spot in a desert!

The study used two 200-pound pig models that were dressed up in jeans and a button-up shirt by students, since murder victims are commonly clothed. They were left to decompose in large cages (to keep scavenging animals away) in various environments and seasons in the Sonoran Desert.

After 25 days, the remains were moved to a secondary burial location. Then, over a period of nine months, the researchers tested the soil where the model was originally placed, where it was moved and in a location adjacent to the original burial as a control.

It's a multifaceted, year-round project to try to determine timing, insects involved, and the humidity and the temperature and many other of these factors.

What they found were distinct microbial fingerprints where death gave way to new life—bacteria and fungi that once lived inside or on the body and were released into the surrounding ground as decomposition occurred.

It's like the murder victim is leaving a signature of themselves in death … almost like leaving breadcrumbs right around the desert (indicating) that they had been there, and those breadcrumbs stayed there in the soil, invisible to the naked eye for a year.

The results definitely opened the door to a novel area of forensic science that has many avenues to explore and to still verify.

Katelyn L. Bolhofner et al, The forensic footprint: Elemental and microbial evidence in relocated remains, Journal of Forensic Sciences (2025). DOI: 10.1111/1556-4029.70092

Comment by Dr. Krishna Kumari Challa 42 minutes ago

Climate change is slowing Earth's spin at unprecedented rate compared to past 3.6 million years

Climate change is lengthening our days because rising sea levels slow Earth's rotation. Researchers now show that the current increase in day length—1.33 milliseconds per century—is unprecedented in the past 3.6 million years. The team reconstructed ancient day-length fluctuations using the fossil remains of single-celled marine organisms known as benthic foraminifera.

An exact 24-hour day is not a given—day length changes due to gravitational effects of the moon, as well as various geophysical processes acting within Earth's interior, at its surface, and in the atmosphere.

Today's climate change also affects day length: prior work showed that from 2000 to 2020 our days were lengthened by a rate equivalent to 1.33 milliseconds per century due to climate-related factors, especially the continental-ocean mass redistribution due to the melting of polar ice sheets and mountain glaciers.

In a new study, appearing in the Journal of Geophysical Research: Solid Earth, researchers demonstrate that this rapid rise in day length is unparalleled over the last 3.6 million years.

The researchers used the fossilized remains of single-celled marine organisms known as benthic foraminifera. From the chemical composition of the foraminifera fossils, they could infer sea-level fluctuations and then mathematically derive the corresponding changes in day length.

To draw more robust conclusions, the team employed a probabilistic deep learning algorithm—a physics-informed diffusion model. This model captures the physics of sea-level change, while remaining robust to the large uncertainties inherent in paleoclimate data.

During the Quaternary (2.6 million years), the growth and melting of large continental ice sheets repeatedly caused significant day-length variations via sea-level changes. Compared with values from the 21st century, however, it is clear that today's increase in day length stands out in the climate history of the past 3.6 million years.

"Only one time—around 2 million years ago—the rate of change in length of day was nearly comparable, but never before or after that has the planetary 'figure skater' raised her arms and sea levels so quickly as in 2000 to 2020", say the researchers. 

This rapid increase in day length implies that the rate of modern climate change has been unprecedented at least since the late Pliocene, 3.6 million years ago. The current rapid rise in day length can thus be attributed primarily to human influences.

By the end of the 21st century, climate change is expected to affect day length even more strongly than the moon. Even though the changes are only milliseconds, they can cause problems in many areas, according to the researchers.

Mostafa Kiani Shahvandi et al, Climate‐Induced Length of Day Variations Since the Late Pliocene, Journal of Geophysical Research: Solid Earth (2026). DOI: 10.1029/2025jb032161

Comment by Dr. Krishna Kumari Challa 22 hours ago

Mouse brains revived from frozen
Researchers have, for the first time, cryogenically frozen and then revived mouse brains with some of the brain functionality intact. The team used an ice-free method called vitrification, which preserves tissue in a glass-like state, and a thawing process that preserves living tissue. After the brains were warmed up, wafer-thin slices from the hippocampus showed signs that the structures that support learning and memory had survived. Researchers are looking to test the method for human brains and organs, but observers note that the success rate was low for mice and the results might not translate to larger body parts.

https://www.nature.com/articles/d41586-026-00756-w?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa yesterday

Mothers' exposure to microbes protects their newborn babies against infection
Newborns are generally protected against severe Escherichia coli infection due to maternal antibodies transferred during pregnancy, which are stimulated by maternal exposure to microbes. Babies with lower levels of these antibodies are at higher risk for infection. Mouse models indicate that maternal probiotic exposure before pregnancy enhances antibody-mediated protection in offspring.

Sing Sing Way, Natural maternal immunity protects neonates from Escherichia coli sepsis, Nature (2026). DOI: 10.1038/s41586-026-10225-z. www.nature.com/articles/s41586-026-10225-z

Comment by Dr. Krishna Kumari Challa yesterday

Spinal stimulation above and below injury restores leg movement and sensory feedback in clinical trial

Simultaneous electrical stimulation above and below spinal cord injury sites enabled individuals with complete paralysis to regain partial leg movement and receive sensory feedback. Participants could control muscle activation and accurately perceive leg position using patterned stimulation and machine learning-optimized protocols. No device-related adverse effects were reported.

Perilesional neuromodulation replaces lost sensorimotor function in persons with spinal cord injury, Nature Biomedical Engineering (2026). DOI: 10.1038/s41551-026-01627-5

Spinal neuromodulation above and below injury restores leg movement and sensory feedback

Comment by Dr. Krishna Kumari Challa yesterday

Antibiotics can affect the gut microbiome for several years, study shows

Antibiotic use can alter the gut microbiome's composition for up to four to eight years, with the extent and duration of changes varying by antibiotic type. Clindamycin, fluoroquinolones, and flucloxacillin showed the strongest associations with long-term microbiome changes, while penicillin V had minimal impact. Even a single antibiotic course can leave lasting effects on gut bacterial diversity.
Antibiotic treatments can affect the composition of the community of bacteria living in the gut, known as the gut microbiome, for a long time. A new study shows that certain types of antibiotics can be linked to changes in the gut microbiome as long as four to eight years after treatment.
Antibiotics can be life-saving in serious infections, but epidemiological studies have also indicated links between high antibiotic use and an increased risk of certain health conditions, such as type 2 diabetes and gastrointestinal infections. The reasons for these observations are not fully understood, but changes in the gut microbiome are thought to play a role.

This has raised questions about the long-term footprint of antibiotics on the gut microbiome. It is well known that antibiotics have a major short-term impact on the gut microbiome.
An international research team of scientists has now found strong links between a person's history of antibiotic use and the composition of their gut microbiome, including the diversity of bacterial species.
'We can see that antibiotic use as far back as four to eight years ago is linked to the composition of a person's gut microbiome today. Even a single course of treatment with certain types of antibiotics leaves traces', say the researchers.
The researchers found that the results differed substantially depending on the type of antibiotic used. The strongest associations were observed for clindamycin, fluoroquinolones, and flucloxacillin. By contrast, penicillin V was linked to small and short-lasting microbiome changes.
The researchers acknowledge that the study only covered prescriptions from the previous eight years and that a longer follow-up period could provide further insights.

Antibiotic use and gut microbiome composition links from individual-level prescription data of 14,979 individuals, Nature Medicine (2026). DOI: 10.1038/s41591-026-04284-y

Comment by Dr. Krishna Kumari Challa on Wednesday

Antibiotic resistance can vary depending on where the bacteria live

New research  indicates that the outcome of a resistance measurement may depend on the conditions under which the bacterium is tested. Standard laboratory tests are carried out under fixed, uniform conditions, but if, for example, the test environment is altered, the very same bacterium may in some cases be either more or less susceptible to an antibiotic than the laboratory result indicates.
When doctors or veterinarians receive a laboratory report stating whether a bacterial sample is resistant to an antibiotic, the answer will typically be that the bacterium is susceptible (and can therefore be treated with antibiotics), or that it is not. That answer is correct for the standardized test conditions laboratories use, and it is this standardization that allows results to be compared across laboratories.

However, standard conditions do not necessarily reflect all the environments bacteria encounter in real life. In the body (and across different hosts), factors such as pH level (how acidic or alkaline an environment is) and temperature can vary, and this may influence how effectively particular resistance genes function.

Understanding how antimicrobial resistance develops and spreads is crucial, as antibiotic resistance has become an imminent threat to global public health.
In the study, the researchers investigated two widely prevalent resistance genes to determine how levels of resistance changed when pH and temperature were varied under controlled laboratory conditions. Among other measures, they quantified the amount of antibiotic required to kill the bacterium as pH was altered.

The researchers also examined the significance of temperatures comparable to the body temperatures of different hosts. Here, they observed an effect at temperatures corresponding to birds (around 42°C) compared with humans (around 37°C).

If a resistance gene functions better at 42°C than at 37°C (or vice versa), this may affect how readily bacteria carrying the gene survive and spread in birds, and thus the extent to which birds may act as hosts for bacteria with that type of resistance.
Antibiotic resistance in bacteria can vary significantly depending on environmental factors such as pH and temperature. The resistance genes CTX-M-15 and CMY-2 showed different levels of antibiotic susceptibility under varying conditions, with CTX-M-15 being strongest in acidic environments and weaker in alkaline ones. These findings suggest that standard laboratory tests may not fully reflect resistance in real-world settings.
Findings
CTX-M-15 conferred the strongest resistance in acidic conditions and became weaker as the environment became more alkaline.
CMY-2 performed better at more alkaline pH than CTX-M-15.
At more alkaline pH, bacteria carrying CTX-M-15 could, in the experiment, shift from resistant to susceptible.
Temperature also affected the results, which may be relevant when comparing different hosts and environments.

Mikkel Anbo et al, Contrasting pH optima of β-lactamases CTX-M and CMY influence Escherichia coli fitness and resistance ecology, Applied and Environmental Microbiology (2026). DOI: 10.1128/aem.01775-25

Comment by Dr. Krishna Kumari Challa on Wednesday

Why lethal mutations persist: Fruit fly study points to newly transferred jumping genes, not small DNA errors
Lethal mutations in wild fruit flies are primarily caused by recently transferred transposable elements, rather than small DNA errors. These jumping genes can rapidly increase mutation rates, temporarily outpacing natural selection until host genomes evolve defenses. This mechanism influences genetic health and persistence of harmful mutations in populations, with implications for conservation and human disease.

Transposable elements contribute substantially to naturally occurring genetic lethality in Drosophila melanogaster, PLOS Biology (2026). DOI: 10.1371/journal.pbio.3003467

Comment by Dr. Krishna Kumari Challa on Wednesday

Scientists discover how falling cats almost always make perfect landings

When cats fall, they usually land on their feet. This uncanny ability to right themselves before hitting the ground has long puzzled people. Now, a research team has the answer, and it's all down to the thoracic spine being more flexible than the lumbar spine, as they detail in a study published in the journal The Anatomical Record.

The air-righting reflex is a complex maneuver that protects cats from serious injury if they fall. As they tumble, the spine twists, which seems to contradict the laws of physics. That's because an object in midair shouldn't be able to turn without something to push against.

To find out how they do it, the researchers first studied the spines of five cat cadavers. They separated the thoracic spine (upper/middle back) from the lumbar spine (lower back) and mechanically tested them under twisting forces to measure flexibility, strength and resistance to rotation. This revealed the capability of a cat's body.

The team also used high-speed cameras to film two healthy cats as they dropped onto a soft cushion. They placed markers on their shoulders and hips to track the movement of their body parts.

The team discovered that the cat's spine is not uniformly flexible. Different parts move in different ways to help the animal land safely. The thoracic spine is incredibly flexible and has a neutral zone, a range where it can twist almost freely for nearly 50 degrees with very little effort. Meanwhile, the lumbar spine is much stiffer and acts as a stabilizer.

During air-righting, the cat rotates its head and front legs toward the ground first because the thoracic spine is flexible and the front of the body is lighter. Then the back half follows. The stiff lumbar spine acts as a solid anchor, allowing the cat to whip its front around without spinning out of control.

These results suggest that trunk rotation during air-righting in cats occurs sequentially, with the anterior trunk rotating first, followed by the posterior trunk, and that their flexible thoracic spine and rigid lumbar spine in axial torsion are suited for this behaviour," commented the study authors in their paper.

Yasuo Higurashi et al, Torsional flexibility of the thoracic spine is superior to that of the lumbar spine in cats: Implications for the falling cat problem, The Anatomical Record (2026). DOI: 10.1002/ar.70165

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