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Category: biotech/medical – Page 25

Reprogramming ‘gatekeeper’ immune cell may boost cancer immunotherapy

St. Jude Children’s Research Hospital scientists have discovered how tumors disable immune “gatekeeper” cells that alert the rest of the immune system to the presence of cancer—and how restoring their energy production can improve immunotherapy. Dendritic cells activate the cytotoxic immune cells that destroy cancer. The researchers found that tumors reduce dendritic cell function by decreasing their mitochondrial fitness, thus preventing formation of the anticancer immune response.

The results, published in Science, also show that boosting mitochondrial function in dendritic cells enhances antitumor immune activity and strengthens the efficacy of existing immunotherapies.

Dendritic cells alert and activate tumor-killing immune cells as a critical part of anticancer immune response. However, within the nutrient-sparse tumor microenvironment (the complex mixture of chemicals, cells and other factors near cancer cells), dendritic cells progressively lose their energy-producing mitochondrial activity. That loss drives dendritic cell dysfunction and weakens the body’s immune defenses against cancer.

New sensor could allow MRIs to see molecular-level changes

You’ve seen people sliding into the tube of a magnetic resonance imaging (MRI) machine on your favorite medical drama, or maybe you’ve been inside one yourself, waiting as the noisy scanner makes images of your brain, heart, bones, or other structures, which doctors use to identify injury or disease.

Since the 1970s, MRIs have been important diagnostic tools, combining a magnetic field and radio waves to produce snapshots of the body’s interior without using ionizing radiation, which can create health risks at higher doses. An MRI can typically capture changes in anatomy, but the molecular-level changes that could further aid understanding of disease have been beyond its reach.

Now, in a new article in Science Advances, University of California, Santa Barbara researchers report the invention of a modular, genetically encoded, protein-based sensor that enables MRI machines to visualize molecular activity inside cells—a development that could transform how scientists study cancer, neurodegeneration, and inflammation.

Scientists just found DNA “supergenes” that speed up evolution

Hidden within fish DNA are powerful genetic twists that may explain one of nature’s biggest mysteries: how new species form so quickly. In Lake Malawi, hundreds of cichlid fish species evolved at lightning speed, and scientists now think “flipped” sections of DNA—called chromosomal inversions—are the secret. These inversions lock together useful gene combinations, creating “supergenes” that help fish rapidly adapt to different environments, from deep waters to sandy shores.

Superconductivity switched on in material once thought only magnetic

Superconductivity—the ability of a material to conduct electricity without any energy loss to heat—enables highly efficient, ultra-fast electronics essential for advanced technologies such as magnetic resonance imaging (MRI) machines, particle accelerators and, potentially, quantum computers. New research has now revealed that iron telluride (FeTe), a compound composed of the chemical elements iron and tellurium and long thought to be an ordinary magnetic metal, is in fact a superconductor. The researchers found that hidden excess iron atoms induce the material’s magnetism, and removing these atoms allows electricity to flow with zero resistance.

Two papers describing the research, both led by Penn State Professor of Physics Cui-Zu Chang, were published back-to-back today (April 1) in the journal Nature. The first paper focuses on how to “switch on” superconductivity in FeTe, while the second paper reveals a new kind of “quantum dance,” where superconductivity interacts with the material’s atomic structure when a different top layer is added, allowing researchers to tune its behavior.

“Unlike the well-known iron-based superconductor iron selenide (FeSe), FeTe has long been considered a magnetic metal without superconductivity, despite having an almost identical crystal structure,” Chang said. “It has remained a mystery why FeTe doesn’t share this important property.”

Precision work prior to cell division: How enzymes optimize DNA structure

Before a cell can divide, it has to precisely duplicate its entire genetic information. However, the DNA in the cell exists as part of a DNA-protein complex known as chromatin. For this purpose, the DNA is wrapped around a core of histone proteins and tightly packed into so-called nucleosomes.

So that the genetic material can be reliably copied, the chromatin has to be temporarily reorganized in certain places and adopt a very specific architecture.

A team led by molecular biologists Professor Axel Imhof and Professor Christoph Kurat at the Biomedical Center (BMC) has now deciphered how the precise packaging of DNA is controlled at the beginning of cell division. The work is published in the journal Nature Communications.

Accuracy test for protein language models shines light into AI ‘black box’

AI language models, used to generate human-like text to power chatbots and create content, are also revolutionizing biology by treating complex biological data like a language. Language models are increasingly used, for example, to find patterns in DNA and proteins, to make predictions and speed research into biological complexity. A critical gap, however, is the lack of a method to estimate the reliability of these predictions.

Computational biologists at Emory University have bridged this gap, developing a simple way to test the accuracy of a language model’s understanding of proteins. Nature Methods has published their system, which scores the reliability of a model’s predictions by comparing how it embeds (numerically codifies) synthetic random proteins versus proteins found in nature.

“To the best of our knowledge, our framework is the first generalized method to quantify protein sequence embedding reliability,” says Yana Bromberg, senior author of the paper and Emory professor of biology and computer science.

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