Comment

Comment by Dr. Krishna Kumari Challa 5 minutes ago

The authors propose that the weakened magnetic field may have allowed more hydrogen to escape to space, resulting in a greater percentage of oxygen in Earth's atmosphere and oceans, which may in turn have supported the diversification in the types and complexity of organisms.

John Tarduno, Near-collapse of the geomagnetic field may have contributed to atmospheric oxygenation and animal radiation in the Ediacaran Period, Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01360-4. www.nature.com/articles/s43247-024-01360-4

Part 2

Comment by Dr. Krishna Kumari Challa 6 minutes ago

Weak magnetic field may have supported diversification of life on Earth

An unusual reduction in the strength of Earth's magnetic field between 591 and 565 million years ago coincided with a significant increase in the oxygen levels in the atmosphere and oceans, according to a paper published in Communications Earth & Environment. The authors propose that the weakening of the magnetic field may have led to the increase in oxygen, which is  thought to have supported the evolution of some of the earliest complex organisms.

Between 600 and 540 million years ago, life on Earth consisted of soft-bodied organisms known as the Ediacaran fauna, the earliest known complex multicellular animals. The fossil record shows that these organisms significantly diversified in complexity and type between 575 and 565 million years ago. Previous research has suggested that this diversification is linked to a significant increase in atmospheric and oceanic oxygen levels that occurred over the same period. However, it is not yet clear why this increase in oxygen occurred.

Researchers analyzed the magnetic properties of 21 plagioclase crystals, a common mineral in Earth's crust, which were extracted from a 591-million-year-old rock formation in Brazil. Plagioclase crystals contain tiny magnetic minerals that preserve the intensity of the Earth's magnetic field at the time they are formed.
Analysis of the crystals showed that at their point of formation, Earth's magnetic field was the weakest ever recorded—some 30 times weaker than both the current magnetic field intensity, and that measured from similar crystals formed approximately 2,000 million years ago.
The authors combined their results with previous measurements to establish that the Earth's magnetic field was at this weak level for at least 26 million years, from 591 to 565 million years ago. This overlaps with the rise in oxygen, which occurred between 575 and 565 million years ago.

Part 1

Comment by Dr. Krishna Kumari Challa 39 minutes ago

Male chicks play more than females!

Play is widespread, but far from ubiquitous, across the animal kingdom. Especially common in mammals, play is also known to occur in taxa as diverse as birds, fish, octopuses, and even insects. But what is its function, given that natural selection never selects fun for its own sake? One prominent hypothesis is that play is beneficial to individuals because it allows them to practice skills needed later in life.

Now, a study in Frontiers in Ethology has shown that male baby chickens play far more than females. This result is of interest given that domestic chickens are directly descended from a species—red jungle fowl—with a pronounced difference between the sexes in morphology, coloration, and behaviour.

This difference is mainly because males engage more in social and object play.

The researchers distinguished 12 distinct play behaviors. Examples of locomotor play were frolicking and wing flapping. Object play included chasing an object or pecking at it or exchanging it with another chick. Social play included sparring, jumping, and sparring stand-offs.

Object play was more frequently seen than social play, while locomotor play was least common. Both females and males showed every type of playful behavior. However, the frequency of play differed between them: male chicks played more overall than females. This was due to males engaging more often in object and social play, while there was no difference between the sexes in the frequency of locomotor play.

The researcher concluded that these sex differences in chicks in the frequency of play can be explained by the high degree of sexual dimorphism of adult junglefowl. This means that male chicks would benefit more from practicing various skills related to physical ability and social tactics.

The present study indicates that a possible function is to prepare animals for specific challenges they may encounter later in life. In a species like the chicken, where only males compete for territories, it makes sense that they engage in more social play as young.

Rebecca Oscarsson et al, Male chicks play more than females—sex differences in chicken play ontogeny, Frontiers in Ethology (2024). DOI: 10.3389/fetho.2024.1392378. www.frontiersin.org/articles/1 … ho.2024.1392378/full

Comment by Dr. Krishna Kumari Challa 48 minutes ago

Researchers develop near-chromosome-level genome for the Mojave poppy bee

Scientists have developed a near chromosome-level genome for the Mojave poppy bee, a specialist pollinator of conservation concern, according to a recent paper published in the Journal of Heredity.

Putting together the Mojave poppy bee genome is part of the Beenome100 project, a first-of-its-kind effort to create a library of high-quality, highly detailed genome maps of 100 or more diverse bee species.

The expectation is that these genomes will help researchers answer the big questions about bees, such as what genetic differences make a bee species more vulnerable to climate change or whether a bee species is likely to be more susceptible to a pesticide.

The Mojave poppy bee and Las Vegas bearpoppy are also being considered for listing under the Endangered Species Act. Both species will be evaluated for potential declining populations and vulnerability to extinction due to climate change and to habitat loss from urban development and mining in their native region.

Researchers assembled the genome or genetic map that will help further to understand the Mojave poppy bee's biological traits.

The genome, with additional genetic sampling of individuals, will also potentially give us insights into the genetic basis for host-plant specialization, susceptibility to pesticides, and susceptibility to drought and climate tolerance.

Rena M Schweizer et al, Reference genome for the Mojave poppy bee (Perdita meconis), a specialist pollinator of conservation concern, Journal of Heredity (2023). DOI: 10.1093/jhered/esad076

Comment by Dr. Krishna Kumari Challa 21 hours ago

Based on previous work by other teams, the researchers selected a few candidate enzymes made by the gut bacterium Akkermansia muciniphila and treated red blood cells – from multiple donors and various A and B subtypes – with them.

Importantly, for potential clinical use, the enzymes were incubated with high concentrations of red blood cells, at room temperature and for only 30 minutes – improving on the longer processing and less efficient conditions of previous candidates.

"These mild conditions without additives (for example, dextran) together with excellent enzyme efficacies are important feasibility parameters in clinical applications.
Crucially, the chosen enzymes also removed all four known extensions of group A and B antigens from red blood cells, in addition to the shorter, canonical A and B antigens of other blood subtypes.

Removing the long, sugary extensions reduced the incompatibility of treated B-type cells with plasma samples to less than 9 percent, and made reactions less severe where they did happen.

More work is required to understand why a small fraction of apparently sugarless red blood cells still cross-react with group O plasmas, and to improve the conversion of group A blood cells.

However, in finding enzymes that remove a greater variety of A and B antigens, the researchers say their study uncovers "a missing link" in the production of universal blood for transfusion and potentially organs for transplantation.

In 2022, researchers used a similar strategy (with different enzymes) to convert donated lungs from group A blood type to the universal type O under lab conditions. This new work might improve those efforts enough to satisfy the safety standards required for human transplant trials.
Lab-grown red blood cells are also in human trials to test whether they last longer than donated blood. If so, that could reduce the demand on blood supplies and also help patients requiring repeat transfusions avoid complications.

https://www.nature.com/articles/s41564-024-01663-4

Part 3

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Comment by Dr. Krishna Kumari Challa 21 hours ago

What's tricky is that there are now, as of 2022, more than 40 blood group systems beyond the ABO system and rhesus factor most are familiar with.

Even within the A and B blood groups, there are subtypes, with varying lengths and densities of the signature molecules protruding from the red cells' membranes.
Scientists recently reported the discovery of remarkably efficient enzymes, not only against A and B antigens but also against their extensions.

published paper

Part 2

Comment by Dr. Krishna Kumari Challa 21 hours ago

Enzymes Discovered in Gut Bacteria Can Change a Donor's Blood Groups

When a life hangs in the balance, blood transfusions can help sustain a patient – but only if the donor's blood type is a match.
A new discovery by researchers from Denmark and Sweden could help in those emergency situations, while also easing global shortages in blood supplies.
The team identified a mixture of enzymes made by a species of bacteria found in our guts that can, in lab studies, transform red blood cells into the universal type O with "remarkably high efficiencies" – improving on an idea hatched 40 years ago.

Like virtually all cells in the human body, red blood cells are covered in a fuzz of unique sugary structures. These vary from person to person, with some sporting type A structures and others type B. Some have both A and B, and others have neither, which is designated O.

Immune systems that have never seen types A or B will attack and destroy these cells on sight if they receive them in a transfusion, whereas type O blood is far more widely accepted for most recipients.

Because of this versatility, type O blood stocks are often used up, especially in medical emergencies where doctors must act quickly without knowing a patient's blood type.
Converting red blood cells into the universal type O is not a new idea. The technique was pioneered back in 1982, when scientists discovered an enzyme extracted from coffee beans that could strip type B cells of their surface sugars.

But that enzyme reaction was very inefficient, making large-scale use impractical, and despite early promise in clinical trials, safety concerns were raised. For unknown reasons, donor blood was sometimes still incompatible in recipients despite donor cells being stripped of nearly all their antigens.

So scientists went back to the drawing board, discovering other enzymes in collections of gut bacteria as recently as 2019.
Part 1

Comment by Dr. Krishna Kumari Challa 22 hours ago

**More than half of cats on farm died after drinking milk from cows infected with bird flu**
In yet another sign that bird flu is spreading widely among mammals, a new report finds more than half of cats at the first Texas dairy farm to have cows test positive for bird flu this spring died after drinking raw milk.

Published this week in the Emerging Infectious Diseases journal, the report details the early stages of the investigation into the spread of bird flu among the country's dairy farms.

Cats at the Texas farm had been fed raw milk from cows that turned out to be infected with avian influenza, also known as H5N1. A day after the farm noticed cows were getting sick, the cats started getting sick. In the end, more than half of the cats perished.
"The cats were found dead with no apparent signs of injury and were from a resident population of [approximately] 24 domestic cats that had been fed milk from sick cows," the scientists wrote in their report.

Tests of the samples collected from the brains and lungs of dead cats yielded results suggesting "high amounts of virus," and autopsies revealed "microscopic lesions consistent with severe systemic virus infection," in the eyes and brain, they said.
And some human beings too got infected with this bird flu virus.

In late March 2024, a human case of influenza A(H5N1) virus infection was identified after exposure to dairy cattle presumably infected with bird flu. Some bird flu infections of people have been identified in which the source of infection was unknown.
Source: The U.S. Centers for Disease Control and Prevention

https://www.cdc.gov/flu/avianflu/avian-in-humans.htm

Comment by Dr. Krishna Kumari Challa 22 hours ago

Tire toxicity faces fresh scrutiny after fish fatalities

For decades, concerns about automobile pollution have focused on what comes out of the tailpipe. Now, researchers and regulators say, we need to pay more attention to toxic emissions from tires as vehicles roll down the road.

At the top of the list of worries is a chemical called 6PPD, which is added to rubber tires to help them last longer. When tires wear on pavement, 6PPD is released. It reacts with ozone to become a different chemical, 6PPD-q, which can be extremely toxic—so much so that it has been linked to repeated fish kills in the US.

The trouble with tires doesn't stop there. Tires are made primarily of natural rubber and synthetic rubber, but they contain hundreds of other ingredients, often including steel and heavy metals such as copper, lead, cadmium, and zinc.

As car tires wear, the rubber disappears in particles, both bits that can be seen with the naked eye and microparticles. Testing by a British company, Emissions Analytics, found that a car's tires emit 1 trillion ultrafine particles per kilometer driven—from 5 to 9 pounds of rubber per internal combustion car per year.

And what's in those particles is a mystery, because tire ingredients are proprietary. You've got a chemical cocktail in these tires that no one really understands and is kept highly confidential by the tire manufacturers.

Regulators have only begun to address the toxic tire problem, though there has been some action on 6PPD.

Native American tribes have petitioned the Environmental Protection Agency to prohibit the chemical. The EPA said it is considering new rules governing the chemical. "We could not sit idle while 6PPD kills the fish that sustain us", they say.

But, tragically,  today there is no alternative to 6PPD.

One outstanding research question is whether 6PPD-q affects people, and what health problems, if any, it could cause. A study published in Environmental Science & Technology Letters found high levels of the chemical in urine samples from a region of South China, with levels highest in pregnant women.

The discovery of 6PPD-q, Molden said, has sparked fresh interest in the health and environmental impacts of tires.

Source: Environmental Science & Technology Letters

Comment by Dr. Krishna Kumari Challa 22 hours ago

Plastic particle air pollution is now pervasive and inhalation ranks as the second most likely pathway for human exposure.
The primary types are intentionally manufactured, including a wide array of cosmetics and personal care products such as toothpaste.

The secondary ones are fragments derived from the degradation of larger plastic products, such as water bottles, food containers and clothes.
Extensive investigations have identified synthetic textiles as a principal source of indoor airborne plastic particles, while the outdoor environment presents a multitude of sources encompassing contaminated aerosols from the ocean to particles originating from wastewater treatment.
Researchers' modelling found that breathing rate along with particle size and shape determined where in the respiratory system plastic particles would be deposited.

Faster breathing rates led to heightened deposition in the upper respiratory tract, particularly for larger microplastics, whereas slower breathing facilitated deeper penetration and deposition of smaller nanoplastic particles.
Particle shape was another factor, with non-spherical microplastic particles showing a propensity for deeper lung penetration compared to spherical microplastics and nanoplastics, potentially leading to different health outcomes.

These findings highlight the imperative consideration of breathing rates and particle sizes in health risk assessments associated with respiratory exposure to nano and microplastic particles.

Xinlei Huang et al, Transport and deposition of microplastics and nanoplastics in the human respiratory tract, Environmental Advances (2024). DOI: 10.1016/j.envadv.2024.100525

Part 2

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