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Comment by Dr. Krishna Kumari Challa 21 hours ago

Finding Clues to Oxygen Production on Early Earth

Possible link between Earth’s rotation rate and oxygenation

Earth's Rotation Is Slowing Down, And Could Explain Why We Have Oxygen

Ever since its formation around 4.5 billion years ago, Earth's rotation has been gradually slowing down, and its days have gotten progressively longer as a result.

While Earth's slowdown is not noticeable on human timescales, it's enough to work significant changes over eons. One of those changes is perhaps the most significant of all, at least to us: lengthening days are linked to the oxygenation of Earth's atmosphere, according to a study from 2021.

Specifically, the blue-green algae (or cyanobacteria) that emerged and proliferated about 2.4 billion years ago would have been able to produce more oxygen as a metabolic by-product because Earth's days grew longer.

There are two major components to this story that, at first glance, don't seem to have a lot to do with each other. The first is that Earth's spin is slowing down. The reason Earth's spin is slowing down is because the Moon exerts a gravitational pull on the planet, which causes a rotational deceleration since the Moon is gradually pulling away. We know, based on the fossil record, that days were just 18 hours long 1.4 billion years ago, and half an hour shorter than they are today 70 million years ago. Evidence suggests that we're gaining 1.8 milliseconds a century.

The second component is something known as the Great Oxidation Event – when cyanobacteria emerged in such great quantities that Earth's atmosphere experienced a sharp, significant rise in oxygen. Without this oxidation, scientists think life as we know it could not have emerged; so, although cyanobacteria may cop a bit of side-eye today, the fact is we probably wouldn't be here without them.

https://www.nature.com/articles/s41561-021-00784-3

Comment by Dr. Krishna Kumari Challa 23 hours ago

Wildfires ignite infection risks by weakening the body's immune defenses and spreading bugs in smoke

We know fire can harm directly, causing injuries and death.

But wildfires, or bushfires, can also have indirect consequences for human health. In particular, they can promote the incidence and spread of a range of infections.

Most people appreciate that fires can cause burns and smoke inhalation, both of which can be life-threatening in their own right. What's perhaps less well known is that both burns and smoke inhalation can cause acute and chronic changes in the immune system. This can leave those affected vulnerable to infections at the time of the injury, and for years to come.

Burns induce profound changes in the immune system. Some parts go into overdrive, becoming too reactive and leading to hyper-inflammation. In the immediate aftermath of serious burns, this can contribute to sepsis and organ failure.

Comment by Dr. Krishna Kumari Challa 23 hours ago

The result of the study changes our understanding of sunburn and the skin's defense mechanisms: that RNA damage triggers a faster and more effective response, protecting the skin from further damage.
The fact that the DNA does not control the skin's initial response to UV radiation, but that something else does and that it does so more effectively and more quickly, is quite the paradigm shift.
We need to understand the function of RNA damage, as it may in the long term change our entire approach to prevention and treatment of sunburn."

"Many inflammatory skin diseases are worsened by sun exposure. Thus, understanding how our skin responds at the cellular level to UV damage opens the door to innovative treatments for certain chronic skin conditions.

Now rewrite the text books!

Anna Constance Vind et al, The ribotoxic stress response drives acute inflammation, cell death, and epidermal thickening in UV-irradiated skin in vivo, Molecular Cell (2024). DOI: 10.1016/j.molcel.2024.10.044

Part 2

Comment by Dr. Krishna Kumari Challa 23 hours ago

Damage to RNA, not DNA, found to be main cause of acute sunburn

We have all been told to avoid direct sunlight between 12 noon and 3 p.m., seek out shade and put on sunscreen and a hat. Nevertheless, most of us have experienced sunburn at least once. The skin turns bright red, feels irritated and needs cooling.

You may also have been told that sunburn damages the DNA. But that is not the full truth, according to researchers responsible for a new study conducted . The findings are published in the journal Molecular Cell.

Sunburn damages the DNA, leading to cell death and inflammation. So the textbooks say. But in this study researchers were surprised to learn that this is a result of damage to the RNA, not the DNA that causes the acute effects of sunburn!

RNA is similar to DNA, but whereas DNA is long lived, RNA is a more transient molecule. A type of RNA, known as messenger RNA (mRNA), functions as the intermediate 'messenger' that carries information from DNA to make proteins—the basic building blocks of cellular components.

DNA damage is serious as the mutations will get passed down to progenies of the cells, RNA damage happens all the time and does not cause permanent mutations. Therefore, we used to think that the RNA is less important, as long as the DNA is intact. But in fact, damages to the RNA are the first to trigger a response to UV radiation.

The new study was conducted on mice as well as human skin cells, and the objective was to describe the impact of UV radiation on the skin and what causes these damages. The researchers found the same skin response to UV radiation exists in both mice and human cells.

mRNA damage triggers a response in ribosomes (protein complexes that "read" the mRNA to synthesize protein), orchestrated by a protein known as ZAK-alpha—the so-called ribotoxic stress response—the new study shows. The response can be described as a surveillance system within the cells, which registers the RNA damage, leading to inflammatory signaling and recruitment of immune cells, which then leads to inflammation of the skin.

Researchers  found that the first thing the cells respond to after being exposed to UV radiation is damage to the RNA, and that this is what triggers cell death and inflammation of the skin. In mice exposed to UV radiation they found responses such as inflammation and cell death, but when they removed the ZAK gene, these responses disappeared, which means that ZAK plays a key role in the skin's response to UV-induced damage.

So you could say that everything depends on this one response, which monitors all protein translations occurring. The cells respond to the RNA damage, realizing that something is wrong, and this is what leads to cell death.

Part 1

Comment by Dr. Krishna Kumari Challa 23 hours ago

India achieves 'historic' space docking mission

India docked two satellites in space Thursday, a key milestone for the country's dreams of a space station and a manned moon mission, the space agency said.

The satellites, weighing 220 kilograms (485 pounds) each, blasted off in December on a single rocket from India's Sriharikota launch site. Later they separated.

The two satellites were maneuvered back together on Thursday in a "precision" process resulting in a "successful spacecraft capture", the Indian Space Research Organisation (ISRO) said, calling it a "historic moment".

India became the fourth country to achieve the feat—dubbed as SpaDeX, or Space Docking Experiment—after Russia, the United States and China.

The aim of the mission was to "develop and demonstrate the technology needed for rendezvous, docking, and undocking of two small spacecraft", ISRO said.

ISRO said the technology is "essential" for India's moon mission.

Source: ISRO

Comment by Dr. Krishna Kumari Challa yesterday

Mosquitoes defy droughts by drinking blood, ensuring survival and disease spread

Mosquitoes are able to survive prolonged droughts by drinking blood, which helps to explain how their populations quickly rebound when it finally rains, biologists found. 

A study examined how two species of mosquito known for infecting people with diseases such as malaria were able to survive nearly three weeks without rain.

The findings could help explain why the incidence of infection from mosquito-borne illness does not always decline during droughts. While there may be fewer mosquitoes, those that survive bite more often.

And mosquitoes appear to be benefiting from climate change as winters get warmer by biting people more!

 Christopher J. Holmes et al, Multiple blood feeding bouts in mosquitoes allow for prolonged survival and are predicted to increase viral transmission during dry periods, iScience (2025). DOI: 10.1016/j.isci.2025.111760

Comment by Dr. Krishna Kumari Challa yesterday

AI-designed proteins neutralize toxins found in snake venom

A study by this year's Nobel Laureate in Chemistry reveals a possible game-changer in snakebite treatment. Researchers have created new proteins that neutralize lethal toxins found in snake venom, potentially offering a safer and more effective alternative to traditional antivenoms.

According to the WHO, venomous snakebites affect between 1.8 and 2.7 million people each year, leading to roughly 100,000 annual deaths and three times as many permanent disabilities, including lost limbs. Most injuries happen in Africa, Asia, and Latin America, where weak health systems aggravate the issue.

Currently, the only antivenoms used to treat snakebite victims are derived from animal plasma and often come with high costs, limited efficacy, and adverse side effects. Venoms also differ widely across snake species, necessitating custom treatments in different parts of the world.

In recent years, however, scientists have gained a deeper understanding of snake toxins and developed new ways to combat their effects. One such development was published on 15 January in Nature.

A team led by 2024 Nobel Laureate in Chemistry David Baker from the University of Washington School of Medicine and Timothy Patrick Jenkins from DTU (the Technical University of Denmark) used deep learning tools to design new proteins that bind to and neutralize toxins from deadly cobras.

The study focuses on an important class of snake proteins called three-finger toxins, which are often the reason antivenoms based on immunized animals fail. While not yet protecting against full snake venom—which is a complex mixture of different toxins unique to each snake species—the AI-generated molecules provide full protection from lethal doses of three-finger toxins in mice: 80–100% survival rate, depending on the exact dose, toxin and designed protein.

These toxins tend to evade the immune system, rendering plasma-derived treatments ineffective. This research thus demonstrates that AI-accelerated protein design can be used to neutralize harmful proteins that have otherwise proven difficult to combat.

David Baker, De novo designed proteins neutralize lethal snake venom toxins, Nature (2025). DOI: 10.1038/s41586-024-08393-x. www.nature.com/articles/s41586-024-08393-x

Comment by Dr. Krishna Kumari Challa yesterday

Marine animals consume microplastic particles and excrete them in feces, posing risks to marine environment

A new  study has uncovered alarming findings about the spread of microplastic particles in the marine food web. In recent years, numerous studies have examined the dangers of marine animals and more specifically, filter-feeding organisms, ingesting non-degradable microplastic particles.

In the current study, the research team sought to understand how the biological filtration by filter-feeding organisms affects the microplastics in their environment. The findings indicate that the particles are excreted in the feces of marine animals, causing them to be unidentifiable as plastic to the marine environment, but potentially as other organic matter suitable for consumption.

Additionally, the presence of microplastic within feces affects feces dispersal, which causes the accumulation of feces and plastic particles. This may increase carbon and nitrogen levels on the seafloor and lead to algal blooms, which have a critical impact on the balance of the marine food web.

Eden Harel et al, Effects of biological filtration by ascidians on microplastic composition in the water column, Chemosphere (2024). DOI: 10.1016/j.chemosphere.2024.143589

Comment by Dr. Krishna Kumari Challa yesterday

Nerves for the suckers also exited from the ANC through these septa, systematically connecting to the outer edge of each sucker. This indicates that the nervous system sets up a spatial, or topographical, map of each sucker.

Octopuses can move and change the shape of their suckers independently. The suckers are also packed with sensory receptors that allow the octopus to taste and smell things that they touch—like combining a hand with a tongue and a nose. The researchers think the "suckeroptopy," as they called the map, facilitates this complex sensory-motor ability.

 Neuronal segmentation in cephalopod arms, Nature Communications (2025). DOI: 10.1038/s41467-024-55475-5

Part 2

Comment by Dr. Krishna Kumari Challa yesterday

Octopus arms have segmented nervous systems to power extraordinary movements

Octopus arms move with incredible dexterity, bending, twisting, and curling with nearly infinite degrees of freedom. New research revealed that the nervous system circuitry that controls arm movement in octopuses is segmented, giving these extraordinary creatures precise control across all eight arms and hundreds of suckers to explore their environment, grasp objects, and capture prey.

Octopus arms move with incredible dexterity, bending, twisting, and curling with nearly infinite degrees of freedom. Credit: Cassady Olson

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Using cellular markers and imaging tools to trace the structure and connections from the ANC, the researchers  saw that neuronal cell bodies were packed into columns that formed segments, like a corrugated pipe. These segments are separated by gaps called septa, where nerves and blood vessels exit to nearby muscles. Nerves from multiple segments connect to different regions of muscles, suggesting the segments work together to control movement.

The best way to set up a control system for this very long, flexible arm would be to divide it into segments.

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