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Category: evolution – Page 42

Researchers at the University of Massachusetts Amherst recently released a first-of-its-kind study focusing on the rare autoimmune disorder aplastic anemia to understand how a subset of cells might be trained to correct the overzealous immune response that can lead to fatal autoimmune disorders. The research, published in Frontiers in Immunology, identifies a specific enzyme known as PRMT5, as a key regulator of suppressive activity in a specialized population of cells.

The is a marvel of evolution. When a pathogen enters the body, can identify it, call for backup, attack the pathogen, and then, when the threat has been eradicated, return to a peaceful state. But sometimes, as in the rare autoimmune disorder aplastic , something goes wrong.

In patients with aplastic anemia, the aberrant immune cells, in this case Th1 cells, misidentify healthy stem cells in bone marrow as pathogenic and attack them. Without these bone marrow stem cells, the body can’t make white blood cells to fight infections, red blood cells to carry oxygen throughout the body, or platelets that help stop bleeding.

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We now have a standard model of cosmology, the current version of the Big Bang theory. Although it has proved very successful, its consequences are staggering. We know only 5% of the content of the universe, which is normal matter. The remaining 95% is made up of two exotic entities that have never been produced in the laboratory and whose physical nature is still unknown.

These are , which accounts for 25% of the content of the cosmos, and dark energy, which contributes 70%. In the standard model of cosmology, dark energy is the energy of empty space, and its density remains constant throughout the .

According to this theory, propagated in the very early universe. In those early stages, the universe had an enormous temperature and density. The pressure in this initial gas tried to push the particles that formed it apart, while gravity tried to pull them together, and the competition between the two forces created sound waves that propagated from the beginning of the universe until about 400,000 years after the Big Bang.

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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 , 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,” says senior author and neuroscientist Robin Franklin of Altos Labs-Cambridge Institute of Science. “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.”

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Polyploidization-rediploidization process plays an important role in plant adaptive evolution. Here, the authors assemble the genomes of mangrove species Sonneratia alba and its inland relative Lagerstroemia speciosa, and reveal genomic evidence for rediploidization and adaptive evolution after the whole-genome triplication.

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Dr. David Cohen comments on 10-year results from a trial of transcatheter vs. surgical aortic valve replacement:

Over the past decade, transcatheter aortic valve replacement (TAVR) has evolved from a niche procedure to treat severe aortic stenosis in high-risk patients to a mainstream procedure that is also performed in intermediate-and low-risk patients. With this evolution in practice, the large number of younger patients with life expectancies 10 years now receiving TAVR has raised concerns about its durability and patients’ long-term outcomes. Now, 10-year results are available from the NOTION trial of TAVR versus surgical aortic valve replacement (SAVR) that was conducted between 2009 and 2013 (NEJM JW Cardiol May 29 2015 and J Am Coll Cardiol 2015; 65:2184).

Two hundred eighty patients aged 70 years (mean age, 79 years; mean predicted risk of surgical mortality, 3%) were randomized to SAVR using any commercially available bioprosthesis or TAVR using the first-generation self-expanding CoreValve device. At 10-year follow-up, there was no significant between-group difference in the composite of death, stroke, or myocardial infarction (66% for both groups) or any of the individual components. Rates of bioprosthetic valve failure and repeat valve intervention were also similar. However, the rate of bioprosthetic valve dysfunction was lower with TAVR, largely reflecting lower rates of patient–prosthesis mismatch. The rate of structural valve deterioration was lower with TAVR as well, driven mainly by lower transvalvular gradients with TAVR that emerged early and persisted throughout follow-up.

Although limited by its modest sample size, the NOTION trial provides the longest available follow-up of any TAVR-versus-SAVR randomized trial to date. Overall, the results provide reassurance that there are no important differences in major clinical outcomes between the two strategies, and the echocardiographic data suggest sustained differences in hemodynamic performance in favor of TAVR. Nonetheless, given the advanced age of the patients at the time of enrollment, we should be cautious in extrapolating these findings to younger patients with severe aortic stenosis or to patients with bicuspid aortic valve disease (who were excluded from NOTION). These findings emphasize the tension between ongoing innovation and the desire for long-term outcomes data for our cardiac devices.

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Cosmologists are wrestling with an interesting question: how much clumpiness does the Universe have? There are competing but not compatible measurements of cosmic clumpiness and that introduces a “tension” between the differing measurements. It involves the amount and distribution of matter in the Universe. However, dark energy and neutrinos are also in the mix. Now, results from a recent large X-ray survey of galaxy clusters may help “ease the tension”

The eROSITA X-ray instrument orbiting beyond Earth performed an extensive sky survey of galaxy clusters to measure matter distribution (clumpiness) in the Universe. Scientists at the Max Planck Institute for Extraterrestrial Physics recently shared their analysis of its cosmologically important data.

“eROSITA has now brought cluster evolution measurement as a tool for precision cosmology to the next level,” said Dr. Esra Bulbul (MPE), the lead scientist for eROSITA’s clusters and cosmology team. “The cosmological parameters that we measure from galaxy clusters are consistent with state-of-the-art cosmic microwave background, showing that the same cosmological model holds from soon after the Big Bang to today.”

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University of Melbourne researchers are leading a new push to address the growing harm of antimicrobial resistance (AMR) as more humans and animals become seriously ill or die from infections that medicine once treated easily.

Over-use and misuse of microbe-killing drugs – including antibiotics, antivirals and antifungals – is the main driver accelerating the evolution of resistance to these drugs in bacteria, viruses, fungi and parasites around the world.

The World Health Organisation calls AMR a top global public health threat that was directly responsible for 1.27 million deaths and contributed to 4.95 million deaths in 2019.

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Scentists have uncovered a fascinating link between ancient viruses and the development of myelination, the biological process crucial for the advanced functioning of the nervous system in vertebrates, including humans.

Scientists discovered a gene, ‘RetroMyelin,’ from ancient viruses, essential for myelination in vertebrates, suggesting viral sequences in early vertebrate genomes were pivotal for developing complex brains. This breakthrough in Cell unravels how myelination evolved, highlighting its significance in vertebrate diversity.

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