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Comment by Dr. Krishna Kumari Challa on May 5, 2023 at 10:02am

Their genetic background—meaning the unique features in the B chromosome flies' genetic make-up—supports their preferential transmission to the next generation. That buys these  evolutionary time to become a new chromosome, whether that's picking up an essential gene or acquiring something that enables them to better cheat.

Importantly, meiotic drive is a powerful force that can shape how genomes evolve. 

Researchers are also examining how specific mutations can lead to chromosome breakage and new chromosome formation, revealing the mechanism of how supernumeraries arise and become requisite components of a genome.

Stacey L. Hanlon et al, B chromosomes reveal a female meiotic drive suppression system in Drosophila melanogaster, Current Biology (2023). DOI: 10.1016/j.cub.2023.04.028

Part 2

Comment by Dr. Krishna Kumari Challa on May 5, 2023 at 10:00am

Scientists discover the dynamics of an 'extra' chromosome in fruit flies

Most chromosomes have been around for millions of years. Now, researchers  have revealed the dynamics of a new, very young chromosome in fruit flies that is similar to chromosomes that arise in humans and is associated with treatment-resistant cancer and infertility. The findings may one day lead to developing more targeted therapies for treating these conditions.

A new study published in Current Biology on May 4, 2023, reveals how this small chromosome that arose less than 20 years ago has persisted in a single, lab-reared strain of the fruit fly, Drosophila melanogaster, and is correlated with supernumerary (extra) chromosomes in humans.

Supernumerary chromosomes in humans are found in cancer cells and frequently interfere with drugs designed to target tumors, making these types of cancers, like osteosarcoma, difficult to treat. In addition, the presence of supernumerary chromosomes in men can disrupt normal chromosome segregation during sperm production, which can cause infertility.

Being able to understand how supernumerary chromosomes arise and what their structures are can potentially illuminate their vulnerabilities. This may enable the development of potential therapeutic targets.

Called B chromosomes—as opposed to the standard "A" set of essential chromosomes—these genetic elements naturally appeared in a single laboratory stock of fruit flies.

Now, the researchers are witnessing chromosome birth and evolution in less than two decades.

How does something like this new chromosome apparently arise from nothing? More important, as these newly born B chromosomes do not possess any known essential genes for fruit fly function, how do they persist in a genome? In short, by cheating. They do not follow the rules.

Researchers discovered that the fruit fly B chromosomes are maintained by a mechanism called "meiotic drive" that enables the them to rebel against the usual rules of inheritance. The B chromosomes drive their way into the next generation during the formation of the egg to ensure their own persistence in more than half of the next generation.

Part 1

Comment by Dr. Krishna Kumari Challa on May 4, 2023 at 11:04am

Birds of a Feather Video-Flock Together: Design and Evaluation of an Agency-Based Parrot-to-Parrot...

Comment by Dr. Krishna Kumari Challa on May 4, 2023 at 10:24am

'Gluing' soft materials without glue!

You're likely familiar with the messy, sticky, frustration-inducing nature of liquid glues. But researchers reporting in ACS Applied Materials & Interfaces now have a brand-new way to weld squishy stuff together without the need for glue at all. They've demonstrated a universal, "electroadhesion" technique that can adhere soft materials to each other just by running electricity through them.

Electroadhesion, in which an electric field is used to hold oppositely charged materials together, forming attachments between the materials' components. This can involve chemical bonds, like ionic bonds, or more physical connections, like ensnaring polymer chains together. Plus, it works with little more than a household battery and pencil lead..

To explore the phenomenon, the team tested a gel in addition to three types of capsules made of alginate or chitosan—both naturally occurring polymers—that were either positively or negatively charged. When attached to graphite electrodes and exposed to a 10-V electric field for around 10 seconds, the oppositely charged materials stuck together.

This bond was strong enough to withstand gravity, and evidence from previous experiments suggests it could last for years. By reversing the flow of electricity, however, the bond was easily broken. .

The researchers also used electroadhesion to sort capsules by their charges, either by laying a charged gel on top of several capsules, or by touching them with a fingertip "robot" that adhered the capsules to themselves. The researchers say that this work demonstrates the universality of electroadhesion and could one day be used in robotics and tissue engineering.

 Leah K. Borden et al, Universal Way to "Glue" Capsules and Gels into 3D Structures by Electroadhesion, ACS Applied Materials & Interfaces (2023). DOI: 10.1021/acsami.2c20793

Comment by Dr. Krishna Kumari Challa on May 4, 2023 at 10:09am

Although India has made major progress in reducing child mortality, diarrhea—caused mostly by contaminated water and food—remains a leading killer.

More than 55,000 children under five died of diarrhea across India in 2019, according to a study published last year in the scientific journal BMC Public Health.

The Yamuna in Delhi is one of the world's filthiest rivers and is considered ecologically dead in places, although people still wash clothes and take ritual baths in it.

It often billows with white foam, and facilities processing drinking water from the river for Delhi's 20 million people regularly shut down because of dangerous ammonia levels.

Despite some bright spots, as well as efforts to plant more trees alongside rivers, the situation elsewhere is often no better in big cities including Mumbai and Chennai.

In Bengaluru, massive Bellandur Lake has on occasion caught fire when methane, generated by bacteria feasting on sewage in the oxygen-depleted water, ignited.

According to the World Bank, India is one of the most "water-stressed" countries in the world, with plummeting water tables and increasingly erratic monsoon rains. India is headed for a water crisis. Sewage can so easily be co-opted to fight that and help us to a very large extent solve the problem in our cities.

India's water is so seasonal. Many cities in India get 50 rain days... but sewage is available every day because you go to the bathroom every day... It's such a powerful weapon.

Children keep falling sick... If they don't get treatment and medicine, the children will die.

Source: 2023 AFP

https://phys.org/news/2023-05-dead-rivers-flaming-lakes-india.html?...

Part 2

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Comment by Dr. Krishna Kumari Challa on May 4, 2023 at 10:07am

Dead rivers, flaming lakes: India's sewage failure

India at the end of April was projected to have overtaken China as the world's most populous country, according to the United Nations, with almost 1.43 billion people.

Its urban population is predicted to explode in the coming decades, with over 270 million more people forecast to live in its cities by 2040.

But of the 72 billion liters of sewage currently generated in urban centers every day, 45 billion liters—enough to fill 18,000 Olympic-sized swimming pools—aren't treated, according to government figures for 2020-21.

India's sewerage system does not connect to about two-thirds of its urban homes, according to the National Faecal Sludge and Septage Management Alliance (NFSSM).

Many of the sewage treatment plants in operation don't comply with standards— according to media reports.

Coupled with huge volumes of industrial effluent, the sewage is causing disease, polluting India's waterways, killing wildlife and seeping into groundwater.

Part 1

Comment by Dr. Krishna Kumari Challa on May 4, 2023 at 9:39am

Scientists find link between photosynthesis and 'fifth state of matter'

Inside a lab, scientists marvel at a strange state that forms when they cool down atoms to nearly absolute zero. Outside their window, trees gather sunlight and turn them into new leaves. The two seem unrelated—but a new study suggests that these processes aren't so different as they might appear on the surface.

The study, published in PRX Energy on April 28, found links at the atomic level between photosynthesis and exciton condensates—a strange state of physics that allows energy to flow frictionlessly through a material. The finding is scientifically intriguing and may suggest new ways to think about designing electronics, the researchers say.

Modeling the complicated interactions of atoms and molecules as they display interesting properties is not possible to see  with the naked eye, so computer modeling can give scientists a window into why the behaviour happens—and can also provide a foundation for designing future technology.

When a photon from the sun strikes a leaf, it sparks a change in a specially designed molecule. The energy knocks loose an electron. The electron, and the "hole" where it once was, can now travel around the leaf, carrying the energy of the sun to another area where it triggers a chemical reaction to make sugars for the plant.

Together, that traveling electron-and-hole-pair is referred to as an "exciton." When the researchers took a birds-eye view and modeled how multiple excitons move around, they noticed something odd. They saw patterns in the paths of the excitons that looked remarkably familiar.

In fact, it looked very much like the behavior in a material that is known as a Bose-Einstein condensate, sometimes known as "the fifth state of matter." In this material, excitons can link up into the same quantum state—kind of like a set of bells all ringing perfectly in tune. This allows energy to move around the material with zero friction. (These sorts of strange behaviors intrigue scientists because they can be the seeds for remarkable technology—for example, a similar state called superconductivity is the basis for MRI machines). According to the models created by the researchers, the excitons in a leaf can sometimes link up in ways similar to exciton condensate behaviour.

Photosynthetic light harvesting is taking place in a system that is at room temperature and what's more, its structure is disordered—very unlike the pristine crystallized materials and cold temperatures that you use to make exciton condensates.

This effect isn't total—it's more akin to "islands" of condensates forming, the scientists say. But that's still enough to enhance energy transfer in the system.

 Anna O. Schouten et al, Exciton-Condensate-Like Amplification of Energy Transport in Light Harvesting, PRX Energy (2023). DOI: 10.1103/PRXEnergy.2.023002

Comment by Dr. Krishna Kumari Challa on May 4, 2023 at 9:20am

How to solve the biggest climate challenges

In a special issue dedicated to climate solutions, The New Yorker explores the breakthroughs that can make the most difference.

• Satellites in development aim to pinpoint the illicit sources of the potent greenhouse gas methane and map carbon in the atmosphere in unprecedented detail. (16 min read)
• People hoping to reduce the carbon emissions from cargo ships — which is on par with the aviation industry — are turning to a time-tested technology: sails. (17 min read)
• Pavagada Ultra Mega Solar Park in southern India is one of the largest solar-generating solar farms in the world — but the people whose livelihoods relied on the land it covers say that not everyone receives a fair share in the fruits of a cleaner economy. (18 min read)

Comment by Dr. Krishna Kumari Challa on May 4, 2023 at 9:18am

Oestrogen does a lot for the brain: it stimulates glucose uptake and energy production. Once the transition to menopause is complete, neurons grow accustomed to its absence. But in the perimenopausal period, levels of the hormone can crash one week only to soar the next. The result can be a period of neuronal discord in which brain cells are periodically deprived of oestrogen, but not for long enough to forge the pathways needed to adapt to life without it.

Perimenopause is also when many of the characteristic symptoms of menopause occur. Hot flushes are the hallmark of perimenopause; other symptoms include irregular periods, anxiety, high blood pressure and the dreaded ‘brain fog’ that impedes concentration. 

It could also be a key time to intervene using treatments that ease the transition into menopause, and which could slow the pace of age-related diseases that seem to accelerate afterwards.

But perimenopause does not have a clear start and end, making it difficult to study. Large clinical trials of treatments such as hormone-replacement therapy have often focused on women who are post-menopausal, sometimes years beyond their last period.

Some women have a short duration of perimenopausal symptoms, and others continue to be symptomatic for years or decades.

Now researchers are taking these changes in the brain seriously and are working to find solutions.

https://www.nature.com/articles/d41586-023-01474-3?utm_source=Natur...

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Comment by Dr. Krishna Kumari Challa on May 4, 2023 at 9:10am

How menopause reshapes the brain

Researchers are starting to learn how the early stages of menopause affect brain health — and what that could mean for treatment.

In studies of post-mortem brains, researchers had found neurons in a region called the hypothalamus that roughly doubled in size in women after menopause. This 's changing so much in postmenopausal women, It had to be important.

Now  a drug called fezolinetant, based on these above discoveries, is being evaluated by the US Food and Drug Administration, with an approval decision expected in the first half of this year. If approved, fezolinetant could be a landmark: the first non-hormonal therapy to treat the source of hot flushes, a symptom that has become nearly synonymous with menopause and one that is experienced by about 80% of women going through the transition.

According to scientists working in the field,  pre-menopause means years of fluctuating hormones that no longer rise and fall in their once-predictable patterns. During this time of perimenopause, circuits in the brain that previously relied on oestrogen signalling can be left floundering.

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