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!
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
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