Comment

Comment by Dr. Krishna Kumari Challa on February 17, 2024 at 9:18am

Why Is It So Hard to Swat a Fly?

Comment by Dr. Krishna Kumari Challa on February 16, 2024 at 8:56am

New study finds little-known toxic crop chemical in four out of five people tested

A new Environmental Working Group study has found chlormequat, a little-known pesticide, in four out of five people tested. Because the chemical is linked to reproductive and developmental problems in animal studies, the findings suggest the potential for similar harm to humans.

EWG's research, published February 15 in the Journal of Exposure Science and Environmental Epidemiology, tested the urine of 96 people for the presence of chlormequat, finding it in 77 of them.

The ubiquity of this little-studied pesticide in people raises alarm bells about how it could potentially cause harm without anyone even knowing they've consumed it.

Environmental Protection Agency regulations allow the chemical to be used on ornamental plants only—not food crops. But now some governments have made concessions that have resulted in these alarming consequences!

 A pilot study of chlormequat in food and urine from adults in the United States from 2017 to 2023, Journal of Exposure Science & Environmental Epidemiology (2024). DOI: 10.1038/s41370-024-00643-4

Comment by Dr. Krishna Kumari Challa on February 16, 2024 at 8:51am

How do oceans start to close? New study suggests the Atlantic may 'soon' enter its declining phase

A new study, resorting to computational models, predicts that a subduction zone currently below the Gibraltar Strait will propagate further inside the Atlantic and contribute to forming an Atlantic subduction system—an Atlantic ring of fire. This will happen 'soon' in geological terms—in approximately 20 million years.

Oceans seem eternal to our lifespan, but they are not here for long: they are born, grow, and one day close. This process, which takes a few hundred million years, is called Wilson Cycle. The Atlantic, for example, was born when Pangea broke up around 180 million years ago and will one day close. And the Mediterranean is what remains from a big ocean—the Tethys– that once existed between Africa and Eurasia.

For an ocean like the Atlantic to stop growing and start closing, new subduction zones—places where one tectonic plate sinks below another—have to form. But subduction zones are hard to form, as they require plates to break and bend, and plates are very strong. A way out of this "paradox" is to consider that subduction zones can migrate from a dying ocean in which they already exist—the Mediterranean—into pristine oceans—such as the Atlantic. This process was dubbed subduction invasion.

This study shows for the first time how such a direct invasion can happen. The computational, gravity-driven 3D model predicts that a subduction zone currently below the Gibraltar Strait will propagate further inside the Atlantic and contribute to forming an Atlantic subduction system—an Atlantic ring of fire, in an analogy to the already existing structure in the Pacific. This will happen 'soon' in geological terms—but not before approximately 20 million years.

João C. Duarte et al, Gibraltar subduction zone is invading the Atlantic, Geology (2024). DOI: 10.1130/G51654.1

Comment by Dr. Krishna Kumari Challa on February 16, 2024 at 8:47am

Scientists report first look at electrons moving in real-time in liquid water

In an experiment akin to stop-motion photography, scientists have isolated the energetic movement of an electron while "freezing" the motion of the much larger atom it orbits in a sample of liquid water.

The findings, reported in the journal Science, provide a new window into the electronic structure of molecules in the liquid phase on a timescale previously unattainable with X-rays. The new technique reveals the immediate electronic response when a target is hit with an X-ray, an important step in understanding the effects of radiation exposure on objects and people.

 Shuai Li et al, Attosecond-pump attosecond-probe x-ray spectroscopy of liquid water, Science (2024). DOI: 10.1126/science.adn6059. www.science.org/doi/10.1126/science.adn6059

Comment by Dr. Krishna Kumari Challa on February 16, 2024 at 8:30am

Ancient retroviruses played a key role in the evolution of vertebrate brains, suggest researchers

Researchers report in the journal Cell that ancient viruses may be to thank for myelin—and, by extension, our large, complex brains.

The team found that a retrovirus-derived genetic element or "retrotransposon" is essential for myelin production in mammals, amphibians, and fish. The gene sequence, which they dubbed "RetroMyelin," is likely a result of ancient viral infection, and comparisons of RetroMyelin in mammals, amphibians, and fish suggest that retroviral infection and genome-invasion events occurred separately in each of these groups.

Retroviruses were required for vertebrate evolution to take off. If we didn't have retroviruses sticking their sequences into the vertebrate genome, then myelination wouldn't have happened, and without myelination, the whole diversity of vertebrates as we know it would never have happened.

Myelin is a complex, fatty tissue that ensheathes vertebrate nerve axons. It enables rapid impulse conduction without needing to increase axonal diameter, which means nerves can be packed closer together. It also provides metabolic support to nerves, which means nerves can be longer.
Myelin first appeared in the tree of life around the same time as jaws, and its importance in vertebrate evolution has long been recognized, but until now, it was unclear what molecular mechanisms triggered its appearance.
The researchers noticed RetroMyelin's role in myelin production when they were examining the gene networks utilized by oligodendrocytes, the cells that produce myelin in the central nervous system.

A retroviral link to vertebrate myelination through retrotransposon RNA-mediated control of myelin gene expression, Cell (2024). DOI: 10.1016/j.cell.2024.01.011. www.cell.com/cell/fulltext/S0092-8674(24)00013-8

Comment by Dr. Krishna Kumari Challa on February 16, 2024 at 8:27am

Researchers discover that a rare fat molecule helps drive cell death

Researchers have found that a rare type of lipid is a key driver of ferroptosis, a form of cell death discovered by  professor Brent Stockwell.

Stockwell first discovered ferroptosis in 2012, when he found that certain cells were dying because their lipid layers were collapsing—an unusual form of  cell death that differs from the most common kind, which begins with the cell forming blisters on its outer surface.

Since that discovery, researchers in Stockwell's lab and elsewhere have continued to investigate ferroptosis, discovering that it can occur naturally in aging cells, in pathological contexts, and can be induced to treat disease.

The findings, appearing in Cell, provide new detail on how cells die during ferroptosis and could improve understanding of how to stop ferroptosis in contexts where it is harmfully occurring—in neurodegenerative diseases, for example—or induce it in contexts where it could be useful, such as using it to kill dangerous cancer cells.

The new research found that a rare type of lipid with two polyunsaturated fatty acyl tails, called a diPUFA phospholipid, was present in a range of contexts where ferroptosis was occurring, including in aging brains and Huntington disease-affected brain tissue. The finding indicates that the lipid is efficient at promoting ferroptosis.

Another paper out in February 2024 with several co-authors found that a gene named PHLDA2 can sometimes promote ferroptosis by attacking a different lipid, and that this gene can block some tumors from forming. Together, these papers show that specific lipids promote ferroptosis, so defining the driver lipids in specific cancers is important.

The discovery that these diPUFA lipids are important drivers of ferroptosis deepens our understanding of this form of cell death, and these lipids' role in controlling a cell's homeostasis in general.

Harnessing these lipids may eventually help us identify where ferroptosis has occurred and deliberately manipulate them to either induce cell death or stop it. This can begin to give us both understanding and the power to control cell death.

Phospholipids with two polyunsaturated fatty acyl tails promote ferroptosis, Cell (2024). DOI: 10.1016/j.cell.2024.01.030. www.cell.com/cell/fulltext/S0092-8674(24)00067-9

Comment by Dr. Krishna Kumari Challa on February 16, 2024 at 8:19am

The researchers suggest that a drug used to treat ulcerative colitis, Crohn's disease and other inflammatory bowel diseases, mesalazine (5-aminosalicylate), may be a treatment for sorbitol intolerance in humans. Mesalazine, also known as mesalamine, functions similarly to the butyrate-producing bacteria, restoring the low oxygen levels in the intestine preferred by Clostridia.

 High fat intake sustains sorbitol intolerance after antibiotic-mediated Clostridia depletion from the gut microbiota, Cell (2024). DOI: 10.1016/j.cell.2024.01.029. www.cell.com/cell/fulltext/S0092-8674(24)00066-7

Part 2

Comment by Dr. Krishna Kumari Challa on February 16, 2024 at 8:18am

Why sugar-free candy and gum give some people gas

Researchers   have identified changes in the gut microbiome that can result in an inability to digest sorbitol. Sorbitol, a sugar alcohol, is used in sugar-free gum, mints, candy and other products. It is also found naturally in apricots, apples, pears, avocadoes and other foods. At high levels, sorbitol can cause bloating, cramps and diarrhea. For some people, even a small amount causes digestive upset, a condition known as sorbitol intolerance.

A new study with mice found that taking antibiotics, combined with a high-fat diet, reduced the number of Clostridia gut microbes, which can break down sorbitol. The findings were published in the journal Cell.

Microbial sorbitol degradation normally protects the host against sorbitol intolerance. However, an impairment in the microbial ability to break down sorbitol causes sorbitol intolerance.

The researchers used metagenomic analysis to identify which gut bacteria have genes that make the enzyme that breaks down sorbitol. They also identified which of those gut bacteria were plentiful before—but not after—antibiotic treatment.

This analysis allowed them to zero in on gut microbes belonging to the class Clostridium. Clostridium are anaerobic, meaning they don't like environments with oxygen.

The researchers found that after the mice were given antibiotics and fed a diet high in saturated fat, the cells lining the gut used less oxygen. This created a higher level of oxygen in the gut, decreasing Clostridia. Without enough Clostridia, sorbitol was not broken down in the gut.

The researchers performed several experiments to try to restore the gut bacteria so it could break down sorbitol again.

In one, they fed the mice Anaerostipes caccae, a gut bacterium that produces butyrate. Butyrate is a short-chain fatty acid produced as part of the normal fermentation process in the gut. It enhances oxygen usage by the cells that line the gut, the epithelial lining, which reduces oxygen levels in the large intestine.

Regulating the oxygen level with Anaerostipes caccae restored the normal levels of Clostridia, which protected the mice from sorbitol-induced diarrhea, even after the butyrate-producing bacteria had been cleared from the mouse's digestive system.

Part 1

Comment by Dr. Krishna Kumari Challa on February 16, 2024 at 7:14am

Space surgery: Doctors on ground operate robot on ISS for first time

Earth-bound surgeons remotely controlled a small robot aboard the International Space Station over the weekend, conducting the first-ever such surgery in orbit—albeit on rubber bands.

The experiment, deemed a "huge success" by the participants, represents a new step in the development of space surgery, which could become necessary to treat medical emergencies during multi-year manned voyages, such as to Mars.

The technology could also be used to develop remote-control surgery techniques on Earth, to serve isolated areas.

The robot, developed by Virtual Incision (VIC) and the University of Nebraska, is called spaceMIRA.

It took off for the International Space Station at the end of January, aboard a payload carried by a SpaceX rocket.

Stored inside a compact box the size of a microwave oven, the robot was installed last Thursday by NASA astronaut Loral O'Hara, who has been in space since last September.

The experiment then took place on Saturday, conducted from Virtual Incision's headquarters in Lincoln, Nebraska.

It lasted around two hours, with six surgeons taking a go at operating the robot, which is equipped with a camera and two arms.

The experiment tested standard surgical techniques like grasping, manipulating and cutting tissue. The simulated tissue is made up of rubber bands," Virtual Incision said in a statement.

In a video shared by the company, one arm equipped with pincers can be seen gripping the band and stretching it, while the other arm equipped with scissors makes a cut—mimicking a dissection.

A key difficulty is the time lag—about 0.85 seconds—between the operation center on Earth and the ISS.

For a control experiment, the same process will take place with the same equipment, but on Earth.

"The experiment was deemed a huge success by all surgeons and researchers, and there were little to no hiccups," Virtual Incision said in a statement, claiming it will "change the future of surgery."

Source: AFP and other news agencies

Comment by Dr. Krishna Kumari Challa on February 15, 2024 at 11:38am

AI-powered ‘eye’ for visually impaired people to ‘see’ objects

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