Comment

Comment by Dr. Krishna Kumari Challa on December 23, 2024 at 9:01am

Antarctica's tipping points threaten global climate stability

Antarctica is approaching a series of cascading tipping points that could reshape ecosystems and intensify global climate disruptions, according to a new study by an international team of scientists.

The study identifies eight potential tipping points spanning physical, biological, chemical, and governance systems. The research is published in the journal Ambio.

These include collapsing ice sheets, invasive species, ocean acidification, and pressures on the Antarctic Treaty System (ATS), which oversees human activity in the region.

The findings highlight the region's critical role in global climate stability.

Antarctica's ice sheets are vital to regulating the Earth's climate and oceans. If they collapse, we'll see significant sea-level rise, impacting millions of people living in coastal areas.

The study warns that these tipping points are interconnected, creating a risk of cascading effects. Melting ice sheets, for example, not only contribute to sea-level rise but also disrupt ocean circulation, which is crucial for transporting heat, carbon, and nutrients around the globe. Such disruptions threaten marine ecosystems, global fisheries, and food security.

The Antarctic Treaty System has been a cornerstone in preserving this fragile environment. But it's increasingly under pressure from geopolitical tensions and expanding human activity. Strengthening it is critical to mitigating these cascading impacts.

Ida Kubiszewski et al, Cascading tipping points of Antarctica and the Southern Ocean, Ambio (2024). DOI: 10.1007/s13280-024-02101-9

Comment by Dr. Krishna Kumari Challa on December 22, 2024 at 11:49am

If our findings here are validated in future studies of independent study populations, mechanistic studies would be needed to disentangle the role of human tonsils and their diseases, via inflammation or other associated health conditions, in the development of psychiatric disorders in general and stress-related disorders specifically," write the researchers.

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2827613

Part 2

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Comment by Dr. Krishna Kumari Challa on December 22, 2024 at 11:47am

Having Your Tonsils removed as a Child May Have a Drastic Impact on Your Life

Thousands of children around the world   have their tonsils surgically removed each year to improve breathing while sleeping or reduce recurrent infection.

A study by an international team of researchers now suggests this relatively common procedure could increase a patient's risk of developing an anxiety-related disorder later in life.

Scientists analyzed data on over a million people held in a Swedish health registry, finding that a tonsillectomy was linked to a 43 percent increased risk of developing conditions such as post-traumatic stress disorder (PTSD), depression, or anxiety. 

Being an observational study, the research can't determine the cause of this outcome, however the increased risk was present even after accounting for the sex of the participants, the age at which they had their tonsils out, any family history of stress-related disorders, and the education level of the parents (an indicator of socioeconomic status).

These findings suggest a potential role of adenotonsillar diseases or associated health conditions in the development of stress-related disorders, the researchers write in their published paper.

Of the conditions identified, PTSD presented the greatest risk increase; a rise of some 55 percent was shown for those who had tonsillectomies earlier in life, compared with those who hadn't.

The researchers compared siblings in some families to control for certain genetic and environmental factors. Even among this sample there was a 34 percent greater risk of anxiety disorders for those family members who had their tonsils removed.

"We found that although the risk increase appeared to be greatest during the first years following surgery, an increased risk of stress-related disorders was still noted more than 20 years after the surgery," write the researchers.

Being a nationwide study with a large sample size, the results provide credible evidence for some kind of link between the surgery and declines in mental health. But what's behind the association?

While we can live without our tonsils, they do help to fight infection, so our bodies are more vulnerable without them. It's also possible that in some cases the reason for the tonsillectomy – like persistent inflammation – might also be the reason for the anxieties later in life.

Previous studies have linked the removal of the tonsils to increases in other health problems, including autoimmune diseases and cancer – and we now have another important consideration to weigh up.

Part 1

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 1:06pm

Commercial tea bags release millions of microplastics, entering human intestinal cells

Do you know why I never use these tea bags? Because my instinct told me they don't have good vibes! And I am right!

Research has characterized in detail how polymer-based commercial tea bags release millions of nanoplastics and microplastics when infused. The study shows for the first time the capacity of these particles to be absorbed by human intestinal cells, and are thus able to reach the bloodstream and spread throughout the body.

Plastic waste pollution represents a critical environmental challenge with increasing implications for the well-being and health of future generations. Food packaging is a major source of micro and nanoplastic (MNPLs) contamination and inhalation and ingestion is the main route of human exposure.

A study by the Mutagenesis Group of the UAB Department of Genetics and Microbiology has successfully obtained and characterized micro and nanoplastics derived from several types of commercially available tea bags. The paper is published in the journal Chemosphere.

The researchers observed that when these tea bags are used to prepare an infusion, huge amounts of nano-sized particles and nanofilamentous structures are released, which is an important source of exposure to MNPLs.

The tea bags used for the research were made from the polymers nylon-6, polypropylene and cellulose. The study shows that, when brewing tea, polypropylene releases approximately 1.2 billion particles per milliliter, with an average size of 136.7 nanometers; cellulose releases about 135 million particles per milliliter, with an average size of 244 nanometers; while nylon-6 releases 8.18 million particles per milliliter, with an average size of 138.4 nanometers.

To characterize the different types of particles present in the infusion, a set of advanced analytical techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (ATR-FTIR), dynamic light scattering (DLS), laser Doppler velocimetry (LDV), and nanoparticle tracking analysis (NTA) were used.

Interactions with human cells observed for the first time.

The particles were stained and exposed for the first time to different types of human intestinal cells to assess their interaction and possible cellular internalization. The biological interaction experiments showed that mucus-producing intestinal cells had the highest uptake of micro and nanoplastics, with the particles even entering the cell nucleus that houses the genetic material.

The result suggests a key role for intestinal mucus in the uptake of these pollutant particles and underscores the need for further research into the effects that chronic exposure can have on human health.

As the use of plastic in food packaging continues to increase, it is vital to address MNPLs contamination to ensure food safety and protect public health, the researchers add.

Gooya Banaei et al, Teabag-derived micro/nanoplastics (true-to-life MNPLs) as a surrogate for real-life exposure scenarios, Chemosphere (2024). DOI: 10.1016/j.chemosphere.2024.143736

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 12:49pm

To steer organizer cells and control stem cell development, the scientists uploaded genetic codes into the cells and engineered two key features in the cells.

First, they instructed the cells to stick to the stem cells in the form of a node or a shell clustering around the clump of stem cells. Second, the investigators engineered the organizer cells to produce specific biochemical signals crucial to inducing early embryonic development.

To effectively and precisely control the organizer cells, researchers developed a chemical switch within the cells, allowing scientists to turn the delivery of instructions to stem cells on or off. Additionally, they installed a "suicide" switch to eliminate the organizer cells when needed.

These synthetic organizers show that we can provide more refined developmental instructions to stem cells by engineering where and when specific morphogen signals are provided.

The organizer cells carry both spatial information and biochemical information, thus giving us an incredible amount of control that we have not had before.

The use of engineered synthetic organizer cells could ultimately allow the team to build real-world applications in the future. The remarkable science of programming instructions to coax stem cells could one day open the door to tackle complex diseases.

Toshimichi Yamada et al, Synthetic organizer cells guide development via spatial and biochemical instructions, Cell (2024). DOI: 10.1016/j.cell.2024.11.017

Part 2

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 12:46pm

Scientists steer the development of stem cells to regenerate and repair organs

Investigators have identified a new way to deliver instructions that tell stem cells to grow into specific bodily structures, a critical step in eventually regenerating and repairing tissues and organs.

The scientists engineered cells that form structures called "synthetic organizers." These organizers provided instructions to the stem cells through biochemical signals called morphogens, which stimulated and enabled the stem cells to grow into specific complex tissues and organ-like assemblies.

The research was conducted with mouse embryonic stem cells, and the findings were published in Cell.

Scientists now can use these synthetic organizers to push the stem cells toward making different parts of the early embryo or toward making a heart or other organs.

In one instance, scientists were able to induce the stem cells to begin to form a mouse body that stretched from head to tail, similar to regular embryonic development in the womb. In another instance, the scientists were able to spur the stem cells to generate a large heart-like structure complete with a central chamber and a regular beat, along with a network of early blood vessels.

This type of synthetic organizer cell platform provides a new way to interface with stem cells and to program what they develop into.

By controlling and reshaping how stem cells differentiate and develop, it might allow us to grow better organs for transplantation or organoids for disease modeling and eventually utilize it to drive tissue regeneration in living patients.

Part 1

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 12:07pm

Removing toxins from potatoes

Scientists have discovered a way to remove toxic compounds from potatoes, making them safer to eat and easier to store. The breakthrough could cut food waste and enhance crop farming in space and other extreme environments.

Potato plants naturally produce chemicals that protect them from insects. The chemicals, called steroidal glycoalkaloids, or SGAs, are found in high quantities in the green parts of potato peels, and in the sprouting areas. They render the potatoes unsafe for insects as well as humans.

These compounds are critical for plants to ward off insects, but they make certain parts of these crops inedible. 

Now that scientists have uncovered the biosynthetic pathway, they can potentially create plants that produce these compounds only in the leaves while keeping the edible parts safe.

Sunlight can induce the production of SGAs in potato "tubers"—the part of the potato plant that is eaten—even after they've been harvested. By identifying a key genetic mechanism in SGA production, researchers may be able to reduce potatoes' toxicity while preserving the plants' natural defenses. Taking SGA out of potatoes will also make them easier to store and transport in open air.

The research, published in Science, focuses on a protein dubbed "GAME15," which plays a key role in directing the plant's production of SGAs. This protein acts both as an enzyme and a scaffold, organizing other enzymes into a "conversion factory" that efficiently produces SGAs while preventing toxic compounds from leaking into other parts of plant cells, where they would wreak havoc.

Tomatoes also produce SGAs, primarily in the green, unripe fruit, as well as in the leaves, stems, and roots of the plants. When the researchers silenced the GAME15 gene in tomatoes, they eliminated SGA production but also made the plants highly susceptible to pests.

By engineering plants to control when and where SGAs are produced, for example, in the leaves but not the potatoes themselves, the researchers envision crops that can be stored without the risk of toxicity from sunlight exposure.

The team achieved these insights by initially recreating the SGA production process in tobacco plants. Surprisingly, they found that during evolution, the process redirected protein from the plasma membrane or Golgi apparatus, where it is responsible for the production of cell wall components crucial for cell growth, to the endoplasmic reticulum, a part of the cell where toxin production begins.

Green, unripe fruit may be toxic, but during ripening these molecules convert to something edible. By limiting SGAs to non-edible parts of plants, farmers and consumers alike could benefit from safer, more versatile crops.

This work demonstrates that plants have evolved ingenious ways to balance growth, reproduction, and defense. Understanding these systems allows us to redesign crops to meet modern needs without compromising their ability to thrive.

 Adam Jozwiak et al, A cellulose synthase–like protein governs the biosynthesis of Solanum alkaloids, Science (2024). DOI: 10.1126/science.adq5721

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 11:55am

Sea snakes regain advanced color vision, recovering a complex trait once lost to evolutionary time

Nine species of sea snakes have now been identified as having regained the genetic requirements for advanced color vision, demonstrating that once a complex trait has been lost to evolutionary time, it may be regained in some way.

A new study found the genetic trait may have existed in a common ancestor of the nine species, which all belong to the Hydrophis genus, dating back three million years.

Researchers previously identified one species of sea snake that had re-elaborated the visual function—the fully marine Hydrophis cyanocinctus, which did so in response to its spectrally complex environment.

With the re-elaboration now identified in so many species, the researchers say there is sufficient evidence to suggest evolutionary losses can be somewhat reversed.

We often think of evolution as a force that moves in just one direction—forward. But really, an organism's ecological circumstances are continuously dynamic, and sometimes becoming the 'fittest' means revisiting traits that were once less beneficial.

The re-elaboration of Hydrophis cyanocinctus' visual function was in response to its bright underwater environment—which differed from the low-light habitats of some of its ancestors.

Snakes descended from lizard-like ancestors which had a full visual opsin complement, which makes sense as they inhabited bright, colorful environments.

The earliest snakes underwent a period of dim-light living, and consequently lost two visual opsin genes, which caused them to lose much of their ability to distinguish colours.

Descendants of these earlier snakes inhabit a diverse variety of light environments today, including bright and colorful marine ecosystems. This opsin expansion showcases how new sensory innovations can more or less re-elaborate visual functions previously thought to be lost.

Though the species of sea snakes identified in this new research have regained the genetic requirements for advanced colour vision, the functions these expanded visual opsins have conferred upon the snakes is unclear and have to be investigated thoroughly now.

 Isaac H Rossetto et al, Dynamic Expansions and Retinal Expression of Spectrally Distinct Short-Wavelength Opsin Genes in Sea Snakes, Genome Biology and Evolution (2024). DOI: 10.1093/gbe/evae150

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 11:38am

How human eyelashes promote water drainage

Throughout human evolution, body and facial hair have notably diminished, yet eyelashes have remained a distinguishing feature. The physiological or functional purpose of eyelashes—traditionally thought to be for catching dust or filtering air—has long been debated.

However, a team of  researchers has recently elucidated the characteristics of human eyelashes. Their study reveals that eyelashes consist of a hydrophobic, curved, flexible fiber array, featuring surface micro-ratchets and a macro-curvature approximating the Brachistochrone curve. This structure enables eyelashes to rapidly and directionally expel incoming liquid, thereby preserving clear vision.

The hydrodynamic advantages of eyelashes, particularly their ability to expel unwanted liquids from the eye to maintain visual clarity, have received little attention. For instance, during facial washing or intense physical activity, the eyes are exposed to significant amounts of water or sweat without compromising clear vision.

The study is published in Science Advances on Dec. 20

The research team aimed to investigate the interaction between water and the flexible fiber array of eyelashes. They began by characterizing the structure, wettability, and water drainage process of human eyelashes. Next, they explored how the flexibility, wettability, and curvature of the fiber array influence water drainage.
Based on their findings, the researchers revealed the control mechanism governing transfer direction and contact time, which arise from the multi-scale asymmetric structures and heterogeneous elastic deformations of the fiber array. They also developed a quantitative computational model to calculate the elastic forces acting on the fiber array.
This research has also led to the design of eyelash-mimetic rapid liquid transfer edges, including aesthetically pleasing and protective false eyelashes, waterproof imaging devices, and ventilated structures.

Shan Zhou et al, Rapid water drainage on human eyelashes of a hydrophobic Brachistochrone fiber array, Science Advances (2024). DOI: 10.1126/sciadv.adr2135. www.science.org/doi/10.1126/sciadv.adr2135

Comment by Dr. Krishna Kumari Challa on December 21, 2024 at 10:45am

Intense ribbons of rain also bring the heat, scientists say

The environmental threat posed by atmospheric rivers—long, narrow ribbons of water vapor in the sky—doesn't come only in the form of concentrated, torrential downpours and severe flooding characteristic of these natural phenomena. According to a new  study, they also cause extreme warm temperatures and moist heat waves.

The atmospheric rivers—horizontal plumes that transport water vapour from the warm subtropics to cooler areas across midlatitude and polar regions of the world—are also transporting heat. As a result, atmospheric rivers may have a greater effect on global energy movement than previously recognized. 

We're seeing temperature anomalies associated with atmospheric rivers that are 5 to 10 degrees Celsius [9 to 18 degrees Fahrenheit] higher than the climatological mean. The numbers are astounding, say the researchers.

The findings are published in the journal Nature.

Scientists began using the term "atmospheric river" in the 1990s. Today, there are three to five of them winding their way through each hemisphere at any given time.

They can be thousands of miles long, but only a few hundred miles wide; the amount of water vapor they carry is about 7–15 times greater than the equivalent amount of water discharged each day by the Mississippi River. The heavy rains that often result can cause major damage and disruption.

The researchers analyzed 40 years of global weather data from NASA's MERRA-2 reanalysis, as well as seven publicly available algorithms that track atmospheric rivers worldwide. Specifically, they looked at temperature increases related to atmospheric rivers on two timescales: hourly temperature spikes and heat waves of three or more days of moist heat.

"There was no doubt—atmospheric rivers are really impactful for both timescales", they conclude.

The researchers noted that the phenomenon has a more dramatic effect in the winter than it does in summer.

The new study shows that when atmospheric rivers occur, they change the balance of energy on the surface in several ways, the researchers say. For example, while cloudy conditions block incoming sunlight, those clouds also trap more thermal radiation near the surface, creating a transient enhanced greenhouse effect. This heating balances out the loss of sunlight—but is not the cause of temperature spikes.

Instead, the main cause of warm temperatures in atmospheric rivers is simply the transport of warm air, located near the water's surface, from one region to another.

Serena R. Scholz et al, Atmospheric rivers cause warm winters and extreme heat events, Nature (2024). DOI: 10.1038/s41586-024-08238-7

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