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Comment by Dr. Krishna Kumari Challa yesterday

Amazon butterflies show how new species can evolve from hybridization

If evolution was originally depicted as a tree, with different species branching off as new blooms, then new research shows how the branches may actually be more entangled. In "Hybrid speciation driven by multilocus introgression of ecological traits," published in Nature,  researchers show that hybrids between species of butterflies can produce new species that are genetically distinct from both parent species and their earlier forebears.

Writing to Charles Darwin in 1861, naturalist Henry Walter Bates described brightly colored Heliconius butterflies of the Amazon as "a glimpse into the laboratory where Nature manufactures her new species." More than 160 years later, an international team of researchers led by biologists Neil Rosser, Fernando Seixas, James Mallet, and Kanchon Dasmahapatra also focused on Heliconius to document the evolution of a new species.
Using whole-genome sequencing, the researchers have shown that a hybridization event some 180,000 years ago between Heliconius melpomene and the ancestor of today's Heliconius pardalinus produced a third hybrid species, Heliconius elevatus. Although descended from hybrids, H. elevatus is a distinct butterfly species with its own individual traits, including its caterpillar's host plant and the adult's male sex pheromones, color pattern, wing shape, flight, and mate choice. All three species now fly together across a vast area of the Amazon rainforest.

Part 1

Comment by Dr. Krishna Kumari Challa yesterday

When scientists simulated a rainfall event in the laboratory, they observed that within the first 15 to 30 minutes, almost all taxonomic groups switched from a resting mode to an active mode. This is a remarkable characteristic of desert soil bacteria, as in other types of soil many groups of bacteria take much longer to reactivate. When reactivated, the bacteria would quickly begin to generate energy and repair their genomes.
In the study, the researchers simulated rainfall events with stable isotope labeled water—water containing heavy hydrogen. Using NanoSIMS, they examined individual cells to see which of them had incorporated the heavy hydrogen atoms.

With this approach, researchers can reveal the fraction of biocrust cells that reactivate in a rain event. We can also infer if they can grow in short rain events that in arid deserts often only last 1 to 2 days.
They found that almost all biocrust cells reactivate, but that in these short rain events only a small proportion of the cells would be able to double. A large proportion of the biocrust cells can therefore use rain events to regenerate and prepare for the next drought, but cell division does not occur.
These data help scientists understand how biocrust bacteria make optimal use of the short activity windows they experience in deserts. They are ideally adapted to withstand short-term changes in soil water content, a very stressful situation for the cells. This allows them to survive the sudden increase in water content during rain, as well as the subsequent drying out.
Additionally, the diverse microbial community is capable of immediate reactivation, which is of great benefit when it must return to a dormant state within a few hours to days.
The findings of this study are relevant not only for desert areas but also for other regions. The ability to survive water limitation will become increasingly important for soil microorganisms in temperate regions, as the frequency and intensity of droughts are increasing due to climate change. Insights gained from desert soil research can help to understand which features make soil microorganisms successful in surviving these challenges.

Survival and rapid resuscitation permit limited productivity in desert microbial communities, Nature Communications (2024). DOI: 10.1038/s41467-024-46920-6

Part 2

Comment by Dr. Krishna Kumari Challa yesterday

Scientists discover how soil microbes survive in harsh desert environments

Prolonged droughts followed by sudden bursts of rainfall—how do desert soil bacteria manage to survive such harsh conditions? This long-debated question has now been answered by an ERC project led by a microbiologist Dagmar Woebken from the Centre for Microbiology and Environmental Systems Science (CeMESS) at the University of Vienna.

The study reveals that desert soil bacteria are highly adapted to survive the rapid environmental changes experienced with each rainfall event. These findings were recently published in the journal Nature Communications.

Drylands cover over 46% of global land area and are expanding, not only due to climate change but also unsustainable land management practices. While plants are seldom encountered in deserts, invisible life thrives belowground. Microorganisms located in the so-called biocrust (the top millimeters to centimeter of the desert soil) enrich the soil with carbon and nitrogen, and also help prevent soil erosion and retain water. But these microbes live in a challenging environment, facing long periods of drought with infrequent rain.
Until now, it was unclear how they could maintain important ecosystem functions under such conditions. Using state-of-the-art methods in microbial ecology, Dagmar Woebken's team gained insights into microbial life in these soils.

Desert soil bacteria endure long drought periods in a state of dormancy, but are reactivated in response to rainfall events, which are short and very rare. The researchers uncovered a kind of "all-in" reactivation strategy in the biocrusts of the Negev Desert, Israel. The bacteria make the most of rainfall events—within this narrow window of activity, almost all microbial soil diversity (as well as individual cells) become active.

Comment by Dr. Krishna Kumari Challa yesterday

To explore whether appeals to our globally shared biology can affect bonding with humanity at large, the study participants watched a TED Talk delivered by journalist A. J. Jacobs explaining how all humans share a common ancestry, portraying us as one large human family.

Those who watched the video expressed significantly stronger psychological bonds with humanity at large compared with a control group whose attitudes were measured before rather than after they had watched the video. Furthermore, participants who watched the video felt stronger social bonds with individuals supporting an opposing political party, compared with the control group.

To investigate whether globally shared experiences can strengthen social bonds on a global scale, the study focused on the common experience of motherhood. The researchers recruited a sample of mothers and showed that mothers felt stronger bonds with other women from all over the world if they shared motherhood experiences with them.

In each case, the strength of social bonds was measured using a series of images of two overlapping circles—one representing the participant and the other one a group, e.g. humanity at large or the group of all the world's mothers. The images differed in the degree of overlap between the two circles. Participants had to choose the image that best represented their relationship with the group, with the images that had the greatest amount of overlap representing the strongest social bonds with the group.

In both studies, the reported psychological bonding on a global scale was strongly reflected in measures of prosocial action. To assess this, the researchers used a measure from behavioral economics, where participants had to indicate how they would split an amount of money between members of two different groups in hypothetical scenarios. This measure is used as a practical and cost-efficient tool in experiments to shed light on how strongly participants care about different groups and has been shown to predict real-stakes behaviour very accurately.
Remembering that we are all related and all experience many of the same challenges in life could be the key to addressing a wide range of global problems, from intergroup conflicts to extreme poverty and the climate crisis, conclude teh researchers.

Why Care for Humanity?, Royal Society Open Science (2024). DOI: 10.1098/rsos.231632. royalsocietypublishing.org/doi/10.1098/rsos.231632

Part 2

Comment by Dr. Krishna Kumari Challa yesterday

Study reveals how humanity could unite to address global challenges

New research has found that perceptions of globally shared life experiences and globally shared biology can strengthen psychological bonding with humanity at large, which can motivate prosocial action on a global scale and help to tackle global problems. The findings have been published recently in Royal Society Open Science.

Many of the most daunting challenges facing humankind today—from the climate crisis and poverty to food insecurity and terrorism—can only be overcome through cooperation and collective action on a global scale. But what would it take to unite humanity in this way?

According to the results of a new study, the key could lie in two of the most potent drivers of social bonding known in group psychology—shared ancestry and shared transformative experiences—albeit shared not only on the level of the tribe, the nation, or the religious community, but with humanity at large.

Us-vs-them thinking is on the rise in many places all over the world, exacerbating conflicts and complicating finding solutions for pressing global problems. This new research, however, suggests that it is possible to foster a shared global identity which could facilitate cooperation on the global level. The practical implications of our findings for policymakers, NGOs, politicians, and activists are wide-ranging.

In two studies involving more than a thousand US participants in total, the researchers investigated whether shared biology and shared experiences with people across the world can foster bonding with humanity at large and motivate prosocial action on a global scale.

Part 1

Comment by Dr. Krishna Kumari Challa on Wednesday

Pigeons are on par with primates in their numerical abilities, according to new University of Otago research appearing in the leading international journal Science.

The Department of Psychology researchers showed that pigeons can compare pairs of images picturing up to nine objects and order them by the lower to higher number with a success rate above chance.

“Pigeons on par with primates in numerical competence,” by Damian Scarf, Harlene Hayne, Michael Colombo. 23 December 2011, Vol 334, Science DOI: 10.1126/science.1213357

https://phys.org/news/2011-12-monkeys-pigeons.html#:~:text=(PhysOrg.com)%20%2D%2D%20Pigeons,the%20leading%20international%20journal%20Science.

Comment by Dr. Krishna Kumari Challa on Wednesday

Quantum electronics: Charge travels like light in bilayer graphene

An international research team has demonstrated experimentally that electrons in naturally occurring double-layer graphene move like particles without any mass, in the same way that light travels. Furthermore, they have shown that the current can be "switched" on and off, which has potential for developing tiny, energy-efficient transistors—like the light switch in your house but at a nanoscale.

Graphene was identified in 2004 and is a single layer of carbon atoms. Among its many unusual properties, graphene is known for its extraordinarily high electrical conductivity due to the high and constant velocity of electrons traveling through this material. This unique feature has made scientists dream of using graphene for much faster and more energy-efficient transistors.

The challenge has been that to make a transistor, the material needs to be controlled to have a highly insulating state in addition to its highly conductive state. In graphene, however, such a "switch" in the speed of the carrier cannot be easily achieved. In fact, graphene usually has no insulating state, which has limited graphene's potential a transistor.

A research team has now found that two graphene layers, as found in the naturally occurring form of double-layer graphene, combine the best of both worlds: a structure that supports the amazingly fast motion of electrons moving like light as if they had no mass, in addition to an insulating state. The researchers showed that this condition can be changed by the application of an electric field applied perpendicularly to the material, making the double-layer graphene insulating.

This property of fast-moving electrons had been theoretically predicted as early as 2009, but it took significantly enhanced sample quality as enabled my materials supplied by NIMS and close collaboration about theory with MIT, before it was possible to identify this experimentally. While these experiments were carried out at cryogenic temperatures—at around 273° below freezing—they show the potential of bilayer graphene to make highly efficient transistors.

 Anna M. Seiler et al, Probing the tunable multi-cone band structure in Bernal bilayer graphene, Nature Communications (2024). DOI: 10.1038/s41467-024-47342-0

Comment by Dr. Krishna Kumari Challa on Wednesday

Scientists develop nanosilver-impregnated silk suture against surgical site infection

In recent years, the adherence of microorganisms to surfaces or coatings has created major health risks to humans. Among these, microbial attachment and growth on surgical suture lines accounts for more than 20% of health-related infections in patients.

As a result, extensive research has been conducted to develop strategies for preventing or reducing the formation of bacterial or fungal colonies on sutures.

Nanosilver has gained significant attention among researchers due to its long-known antimicrobial properties. Its optical and structural characteristics make it an appealing candidate for biomedical applications.

It can be synthesized using both green and chemical methods, although it typically carries a negative charge, which can compromise its stability and storage capabilities.

The biological impact of this synthesis was recently published in ACS Omega, where its effectiveness in coating silk sutures and inhibiting the growth of microorganisms was detailed by the research team.

Diego Antonio Monroy Caltzonci et al, Antimicrobial and Cytotoxic Effect of Positively Charged Nanosilver-Coated Silk Sutures, ACS Omega (2024). DOI: 10.1021/acsomega.4c01257

Comment by Dr. Krishna Kumari Challa on Wednesday

They tried different concentrations of Murakami's reagent and different time spans for etching. One day, one week, one month, several months. What they noticed was that the lower the concentration and the longer the etching process, the better. But it still wasn't enough.

The etching must also be carried out in the dark as cyanide develops in the reaction when it is struck by light, and it dissolves gold. The last step was to get the gold sheets stable. To prevent the exposed two-dimensional sheets from curling up, a surfactant was added. In this case, a long molecule that separates and stabilizes the sheets, i.e. a tenside.

The goldene sheets are in a solution, a bit like cornflakes in milk. Using a type of 'sieve,' the researchers can collect the gold and examine it using an electron microscope to confirm that they have succeeded. Which they have!

The new properties of goldene are due to the fact that the gold has two free bonds when two-dimensional. Thanks to this, future applications could include carbon dioxide conversion, hydrogen-generating catalysis, selective production of value-added chemicals, hydrogen production, water purification, communication, and much more. Moreover, the amount of gold used in applications today can be much reduced.

Synthesis of goldene comprising single-atom layer gold, Nature Synthesis (2024). DOI: 10.1038/s44160-024-00518-4

Part 2

Comment by Dr. Krishna Kumari Challa on Wednesday

A single atom layer of gold—researchers create goldene

For the first time, scientists have managed to create sheets of gold only a single atom layer thick. The material has been termed goldene. According to researchers , this has given the gold new properties that can make it suitable for use in applications such as carbon dioxide conversion, hydrogen production, and production of value-added chemicals. Their findings are published in the journal Nature Synthesis.

Scientists have long tried to make single-atom-thick sheets of gold but failed because the metal's tendency to lump together.

But researchers  have now succeeded thanks to a hundred-year-old method used by Japanese smiths.

If you make a material extremely thin, something extraordinary happens—as with graphene. The same thing happens with gold. As you know, gold is usually a metal, but if single-atom-layer thick, the gold can become a semiconductor instead.

To create goldene, the researchers used a three-dimensional base material where gold is embedded between layers of titanium and carbon. But coming up with goldene proved to be a challenge. According to the researchers,  part of the progress is due to serendipity.

They had created the base material with completely different applications in mind. They started with an electrically conductive ceramics called titanium silicon carbide, where silicon is in thin layers. Then the idea was to coat the material with gold to make a contact. But when they exposed the component to high temperature, the silicon layer was replaced by gold inside the base material.

This phenomenon is called intercalation and what the researchers had discovered was titanium gold carbide. For several years, the researchers have had titanium gold carbide without knowing how the gold can be exfoliated or panned out.

Then the researchers found a method that has been used in Japanese forging art for over a hundred years. It is called Murakami's reagent, which etches away carbon residue and changes the color of steel in knife making, for example. But it was not possible to use the exact same recipe as the smiths did. Scientists had to look at modifications.

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