In a finding that broadens our understanding of how the immune system can detect infection, researchers have identified a previously unappreciated way in which bacteria can be recognized inside our cells.
Many bacteria cause disease by invading cells and creating a safe niche in which to replicate. Cells respond to the infection by activating the immune system, and a chief challenge for bacteria is to avoid immune detection. Prior research had shown that bacteria inside the cytosol (the cells expansive gel-like compartment) could be detected, but how bacteria within the cytosol are recognized has not been clear.
In the new work, Dr. John Brumell and colleagues at The Hospital for Sick Children studied the fate of Salmonella bacteria within the cytosol. These bacteria normally occupy vacuoles in host cells, but under some conditions they leave the vacuole and enter the cytosol. In this foreign environment, the bacteria were recognized by the ubiquitin system, a protein machine that applies molecular tags to cellular proteins to target them for destruction by the proteasome, essentially a molecular shredding device inside mammalian cells. These findings suggest that bacterial proteins are being destroyed by the proteasome within the cytosol during infection, and that this may play a key role in activation of the immune system. A surprising result came when Salmonella was compared with Listeria, a bacterium which normally occupies the cytosol. Listeria avoided recognition by the ubiquitin system by moving within this compartment. This suggests that Listeria and other bacteria that can colonize the cytosol do so in a manner that prevents activation of the immune system.
Heidi Hardman | EurekAlert!
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Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
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The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
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With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
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An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
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