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Comment by Dr. Krishna Kumari Challa on February 14, 2025 at 9:36am

Birds have developed complex brains independently from mammals, studies reveal

Two studies published in the latest issue of Science have revealed that birds, reptiles, and mammals have developed complex brain circuits independently, despite sharing a common ancestor. These findings challenge the traditional view of brain evolution and demonstrate that, while comparable brain functions exist among these groups, embryonic formation mechanisms and cell types have followed divergent evolutionary trajectories.

The pallium is the brain region where the neocortex forms in mammals, the part responsible for cognitive and complex functions that most distinguishes humans from other species. The pallium has traditionally been considered a comparable structure among mammals, birds, and reptiles, varying only in complexity levels. It was assumed that this region housed similar neuronal types, with equivalent circuits for sensory and cognitive processing.

Previous studies had identified the presence of shared excitatory and inhibitory neurons as well as general connectivity patterns suggesting a similar evolutionary path in these vertebrate species.

However, the new studies reveal that, although the general functions of the pallium are equivalent among these groups, its developmental mechanisms and the molecular identity of its neurons have diverged substantially throughout evolution.

Eneritz Rueda-Alaña et al, Evolutionary convergence of sensory circuits in the pallium of amniotes, Science (2025). DOI: 10.1126/science.adp3411. www.science.org/doi/10.1126/science.adp3411

Zaremba B et al. Developmental origins and evolution of pallial cell types and structures in birds. Science (2025). DOI: 10.1126/science.adp5182. www.science.org/doi/10.1126/science.adp5182

Comment by Dr. Krishna Kumari Challa on February 14, 2025 at 9:29am

The research team found almost 30 different guardian candidates and decided to pursue one of them further: PROX1 (Prospero homeobox protein 1).

Studies on the liver cancer model showed that the team had hit the mark.
It turned out that PROX1 is a very influential guard in liver cells. If it is missing, the liver cells change their phenotype. And conversely, the versatility of tumor cells can be reduced by experimentally inducing an increase in the activity of the guard.
PROX1 was able to override the influence of such strong cancer drivers and suppress the formation of tumors despite their presence.
The researchers also found something else: the PROX1 guardian must be constantly active around the clock to fulfill its function. This is different from many other gene switches, which, like a toggle switch, only need to be activated briefly.

Lim B et al, Active repression of cell fate plasticity by PROX1 safeguards hepatocyte identity and prevents liver tumourigenesis. Nature Genetics (2025). DOI: 10.1038/s41588-025-02081-w

Part 2

Comment by Dr. Krishna Kumari Challa on February 14, 2025 at 9:27am

Guardian molecule keeps cells on track

A guardian molecule ensures that liver cells do not lose their identity. This has been discovered by researchers. 

The research is published in Nature Genetics.

The discovery is of great interest for cancer medicine because a change of identity of cells has come into focus as a fundamental principle of carcinogenesis for several years. The researchers were able to show that the newly discovered sentinel is so powerful that it can slow down highly potent cancer drivers and cause malignant liver tumors to regress in mice.

As a rule, the identity of cells is determined during embryonic development. They differentiate into nerve cells or liver cells, for example, and their fate is sealed. Only stem cells retain the ability to develop in different directions. However, once cells have differentiated, they usually stay on course.

Cancer cells are different. They have the amazing ability to reactivate embryonic programs and thus change their identity—their phenotype. This ability is referred to as—unwanted or abnormal—plasticity.

It enables tumor cells to break away from the cell network and migrate through the body. Once they have arrived in the target organ, the cells differentiate again, become sedentary again and form metastases at this site.

It is not so long ago that the importance of plasticity as a fundamental phenomenon in cancer was recognized.

The researchers' goal is to reduce the plasticity of cancer cells and thus prevent the development and spread of malignant tumors. To do this, they first need to understand how cell plasticity is regulated.

In principle, almost all cells in the body have an identical genome. But how is it possible then that such different and highly specialized cell types as nerve cells or liver cells arise?

This is only possible because cells have a sophisticated control network.

These ensure that only certain genes are switched on, depending on the cell type, while others are permanently silenced. Master regulators play a central role in this process. They switch on genes that influence specialized cells to change their identity and even acquire stem cell properties.

However, little is known about the antagonists—the control instances that prevent unwanted (re)transformation of differentiated cells by switching off certain genes.

The researchers used a computer program to search for gene switches that could potentially serve as guardians.

Part 1

Comment by Dr. Krishna Kumari Challa on February 14, 2025 at 8:46am

Can organisms help others around even after their death?

Bacteria evolved to help neighboring cells after death, new research reveals

Darwin's theory of natural selection provides an explanation for why organisms develop traits that help them survive and reproduce. Because of this, death is often seen as a failure rather than a process shaped by evolution.

When organisms die, their molecules need to be broken down for reuse by other living things. Such recycling of nutrients is necessary for new life to grow.

Researchers have shown that a type of E. coli bacteria produces an enzyme which breaks the contents of their cells down into nutrients after death. The dead bacteria are therefore offering a banquet of nutrients to the cells that were their neighbours when they were living.

The study has been published in Nature Communications.

We typically think of death being the end, that after something dies it just falls apart, rots and becomes a passive target as it is scavenged for nutrients.

But what this new work has demonstrated is that death is not the end of the programmed biological processes that occur in an organism.

Those processes continue after death, and they have evolved to do so.

"That is a fundamental rethink about how we view the death of an organism."

The researchers  realized they had stumbled across a potentially new area of biology; processes that have evolved to function after death.

One problem remained; the researchers couldn't work out how an enzyme that functions after death could have evolved.

"Typically, we think of evolution acting on living organisms not dead ones.

"The solution is that neighboring cells which gain nutrients from the dead cells are likely to be clonally related to the dead cell.

Consequently, the dead cell is giving nutrients to its relatives, analogous to how animals will often help feed younger members of their family group.

The finding demonstrates that processes after death, like processes during life, can be biologically programmed and subject to evolution. Biomolecules that regulate processes after death might be exploited in the future as novel targets for bacterial disease or as candidates to enhance bacterial growth in biotechnology.

Bacteria encode post-mortem protein catabolism that enables altruistic nutrient recycling, Nature Communications (2025). DOI: 10.1038/s41467-025-56761-6

Comment by Dr. Krishna Kumari Challa on February 14, 2025 at 8:34am

To simplify the problem, the team made two key assumptions. First, they treated the vast environment surrounding the system in such a way that they could focus only on the quantum system itself. Second, they assumed that the environment—like the entire universe—is so large that energy and information dissipate into it, never returning.

This approach enabled them to examine how time emerges as a one-way phenomenon, even though, at the microscopic level, time could theoretically move in both directions.
Even after applying these assumptions, the system behaved the same way whether time moved forward or backwards. This discovery provided a mathematical foundation for the idea that time-reversal symmetry still holds in open quantum systems—suggesting that time's arrow may not be as fixed as we experience it.
'The surprising part of this project was that even after making the standard simplifying assumption to our equations describing open quantum systems, the equations still behaved the same way whether the system was moving forwards or backwards in time', say the researchers.
When the physicists carefully worked through the math, they found that this behavior had to be the case because a key part of the equation, the 'memory kernel,' is symmetrical in time.

They also found a small but important detail which is usually overlooked—a time discontinuous factor emerged that keeps the time-symmetry property intact. It's unusual to see such a mathematical mechanism in a physics equation because it's not continuous, and it was very surprising to see it pop up so naturally.

Thomas Guff et al, Emergence of opposing arrows of time in open quantum systems, Scientific Reports (2025). DOI: 10.1038/s41598-025-87323-x

Part 2

Comment by Dr. Krishna Kumari Challa on February 14, 2025 at 8:31am

Physicists uncover evidence of two arrows of time emerging from the quantum realm

What if time is not as fixed as we thought? Imagine that instead of flowing in one direction—from past to future—time could flow forward or backwards due to processes taking place at the quantum level. This is the thought-provoking discovery made by researchers , as a new study reveals that opposing arrows of time can theoretically emerge from certain quantum systems.

For centuries, scientists have puzzled over the arrow of time—the idea that time flows irreversibly from past to future. While this seems obvious in our experienced reality, the underlying laws of physics do not inherently favor a single direction. Whether time moves forward or backwards, the equations remain the same.

One way to explain this is when you look at a process like spilled milk spreading across a table, it's clear that time is moving forward. But if you were to play that in reverse, like a movie, you'd immediately know something was wrong—it would be hard to believe milk could just gather back into a glass.

However, there are processes, such as the motion of a pendulum, that look just as believable in reverse. The puzzle is that, at the most fundamental level, the laws of physics resemble the pendulum; they do not account for irreversible processes.

The new findings suggest that while our common experience tells us that time only moves one way, we are just unaware that the opposite direction would have been equally possible."

The study, published in Scientific Reports, explored how a quantum system—the world of the sub-atomic—interacts with its environment, known as an "open quantum system."

Researchers investigated why we perceive time as moving in one direction, and whether this perception emerges from open quantum mechanics.

Part 1

Comment by Dr. Krishna Kumari Challa on February 13, 2025 at 11:51am

The sexome's forensic potential: After intercourse, both partners leave traces of their own unique genital microbiome

Criminal investigations of heterosexual sexual assault often include a DNA analysis of the woman's genitals with the aim of identifying the presence of the perpetrator's sperm for proof of intercourse. However, in cases where no sperm is detected, including in assaults where the perpetrator uses a condom, these exams are often ineffective.

In research published in iScience on February 12, 2025, researchers show that bacterial species are transferred between both individuals during sexual intercourse, and these species can be traced to a sexual partner's unique genital microbiome.

The authors say that analyses of these genital microorganisms—which they called the "sexome"—may be useful in identifying perpetrators of sexual assault.

This research is based on the forensic concept that every contact leaves a trace.

In this study, the researchers confirmed that both men and women have unique populations of bacteria in their genital areas. They then recruited 12 monogamous, heterosexual couples to investigate whether these sexomes are transferred during sexual intercourse, including when a condom is used.

At the beginning of the study, each participant collected samples of their genital microbiome using swabs. The investigators used RNA gene sequencing to determine which bacteria strains were present—down to the sub-species level—and identified microbial signatures for each participant.

Couples were then asked to abstain from sex for varying lengths of time (from two to 14 days) and then to participate in intercourse. Afterwards, samples were collected again from each individual's genital microbiome. Analysis showed that a participant's unique bacterial signature could be identified in their sexual partner's sample following intercourse.

Three of the couples reported using a condom. The analysis found that although this did have some impact on the transfer of microbial content, it did not inhibit it entirely.

When a condom was used, the majority of transfer occurred from the female to the male.

This shows promise for a means of testing a perpetrator post-assault and means there may be microbial markers that detect sexual contact even when a condom was used.

The investigators also looked at whether males were circumcised and whether the participants had pubic hair, but found that neither factor seemed to affect the transfer of bacterial species between partners. However, they did find that the makeup of the vaginal microbiome changed during menstruation, which they note could affect results.

You can escape from police and law but you cannot escape from science and scientists. Can you?

 Bacterial transfer during sexual intercourse as a tool for forensic detection, iScience (2025). DOI: 10.1016/j.isci.2025.111861. www.cell.com/iscience/fulltext … 2589-0042(25)00121-X

Comment by Dr. Krishna Kumari Challa on February 13, 2025 at 11:44am

Diabetes can drive the evolution of antibiotic resistance, study suggests

Antibiotics are powerful, fast-acting medications designed to eradicate bacterial infections. However, in recent years, their dependability has waned as antibiotic resistant bacteria continues to evolve and spread.

Staphylococcus aureus is a leading cause of antibiotic-resistance-associated infections and deaths. It is also the most prevalent bacterial infection among those with diabetes mellitus, a chronic condition that affects blood sugar control and reduces the body's ability to fight infections.

Researchers have just shown that people with diabetes are more likely to develop antibiotic-resistant strains of Staph, too.

Their results, which were published in Science Advances, show how the diabetic microbial environment produces resistant mutations, while hinting at ways antibiotic resistance can be combated in this patient population.

The researchers found that antibiotic resistance emerges much more rapidly in diabetic models than in non-diabetic models of disease.

This interplay between bacteria and diabetes could be a major driver of the rapid evolution and spread of antibiotic resistance that we are seeing.

Diabetes affects the body's ability to control a type of sugar called glucose, often causing excess glucose to build up in the bloodstream. Staph feeds off these high sugar levels, allowing it to reproduce more rapidly. The bacterium can also grow without consequence, as diabetes also impairs the immune system's ability to destroy cells and control infection.

As the numbers of bacteria increase in a diabetic infection, so does the likelihood of resistance. Random mutations appear and some build up resistance to external stressors, like antibiotics. Once a resistant mutant is present in a diabetic infection, it rapidly takes over the population, using the excess glucose to drive its rapid growth.

Staphylococcus aureus is uniquely suited to take advantage of this diabetic environment.

Once that resistant mutation happens, you have excess glucose and you don't have the immune system to clear the mutant and it takes over the entire bacterial population in a matter of days.

This was proved in their experiments and models. 

So, what can be done to prevent it? Well, the researchers  showed that reducing blood sugar levels in diabetic models (through administration of insulin) deprived bacteria of their fuel, keeping their numbers at bay, and reducing the chances of antibiotic-resistant mutations from occurring.

Their findings suggest that controlling blood sugar through insulin use could be key in preventing antibiotic resistance.

John Shook et al, Diabetes Potentiates the Emergence and Expansion of Antibiotic Resistance, Science Advances (2025). DOI: 10.1126/sciadv.ads1591. www.science.org/doi/10.1126/sciadv.ads1591

Comment by Dr. Krishna Kumari Challa on February 13, 2025 at 11:01am

Mimicry: Masquerading moth deploys specialized nanostructures to evade predators

Researchers found the forewings of the fruit-sucking moth (Eudocima aurantia) have the appearance of a crumpled leaf—but are in fact flat.

They  published their research in Current Biology  this week.

They found the moth mimics the 3D shape and coloration of a leaf using specialized nanostructures on its wings. These nanostructures create a shiny wing surface that mimics the highlights found on a smooth, curved leaf surface.

Structural and pigmentary coloration produces a leaf-like brown color, with the moth exploiting thin-film reflectors to produce directional reflections—producing the illusion of a 3D leaf shape.

It is intriguing that the nanostructures which produce shininess only occur on the parts of the wing that would be curved if the wing was a leaf. 

This suggests that moths are exploiting the way predators perceive 3D shapes to improve their camouflage, which is very impressive.

What is remarkable about this moth, however, is that it is creating the appearance of a three-dimensional object despite being almost completely flat. 

This mimicry likely serves as a camouflage strategy, fooling predators into misidentifying the moth as an inedible object.

Jennifer L. Kelley et al, A leaf-mimicking moth uses nanostructures to create 3D leaf shape appearance, Current Biology (2025). DOI: 10.1016/j.cub.2025.01.029. www.cell.com/current-biology/f … 0960-9822(25)00059-4

Comment by Dr. Krishna Kumari Challa on February 13, 2025 at 10:34am

This research offers a new perspective on how molecular evolution might have unfolded on early Earth.
By demonstrating that chemical systems can self-organize and evolve in structured ways, this work provides experimental evidence that may help bridge the gap between prebiotic chemistry and the emergence of biological molecules.
Beyond its relevance to origins-of-life research, the study's findings may have broader applications in synthetic biology and nanotechnology. Controlled chemical evolution could be harnessed to design new molecular systems with specific properties, potentially leading to innovations in materials science, drug development, and biotechnology.

Evolution of Complex Chemical Mixtures Reveals Combinatorial Compression and Population Synchronicity, Nature Chemistry (2025). DOI: 10.1038/s41557-025-01734-x

Part 2

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