Bacteria can directly cause human blood and plasma to clot—a process that was previously thought to have been lost during the course of vertebrate evolution, according to new research at the University of Chicago, National Institute of Allergy and Infectious Diseases, and Institut Pasteur in Paris. Their findings will be published online Nov. 2 in Nature Chemical Biology.
The discovery will improve scientists' understanding of coagulation during bacterial infections and may lead to new clinical methods for treating serious medical conditions such as sepsis and anthrax.
It has long been known that blood often coagulates during sepsis or bacterial infections, but this has generally been regarded as a host's immune and inflammatory response. It also has been known that bacteria can activate factors that precede coagulation, but it had not previously been known that bacteria can pass the coagulation threshold and cause blood clots to form. Once they form, the clots can grow and propagate. Although this may help prevent the dissemination of the bacteria through the host, it often leads to serious vascular damage due to blocked and injured blood vessels.
The key to clot formation is the location of the bacteria, rather than the total number of bacteria or their level of concentration. In other words, for those bacteria that can activate coagulation factors, coagulation occurs only when a cluster of bacteria forms.
"Our research demonstrates that coagulation can be controlled by changing the spatial distribution, or clustering, of bacteria," said study co-author Christian Kastrup, Post-Doctoral Assistant at the Koch Institute for Integrative Cancer Research at the Massachusetts Institute of Technology. "Therefore, considering the location of bacterial cells, instead of just their presence or absence and their total numbers, could significantly change our understanding of coagulation."
Kastrup, who worked on this research as a graduate student in the Ismagilov Lab at the University of Chicago's Department of Chemistry, is the first author of the Nature paper. Rustem Ismagilov, Professor of Chemistry at the University of Chicago, is the corresponding author. Researchers at the National Institute of Allergy and Infectious Diseases, Institut Pasteur in Paris, and Ben-May Department for Cancer Research at the University of Chicago co-authored the paper.
Coagulation can occur if enough proteases that activate coagulation accumulate near the bacteria, rather than diffuse away. This research used Bacillus anthracis, the anthrax-causing pathogen (using a safe strain that does not infect humans). It found that in the case of human blood, coagulation required the secretion of zinc metalloprotease InhA1, which activated prothrombin and factor X directly—not via factor XII or tissue-factor pathways.
"We refer to this mechanism as 'quorum acting' to distinguish it from quorum sensing, in which bacteria coordinate certain actions based, in part, on their density," said Wei-Jen Tang, Professor at the Ben-May Department for Cancer Research.
This work opens up a new field of study, he added. "We will now explore the commonality of quorum acting, and how quorum acting can affect evolutionary dynamics."
The results of this research have broad implications, according to Ismagilov. "The work emphasizes the importance of bacteria's spatial distribution, rather than just its average concentration in the functioning of nonlinear biochemical networks," he said.
Greg Borzo | EurekAlert!
Funding of Collaborative Research Center developing nanomaterials for cancer immunotherapy extended
28.06.2017 | Johannes Gutenberg-Universität Mainz
Zeolite catalysts pave the road to decentral chemical processes Confined space increases reactivity
28.06.2017 | Technische Universität München
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
28.06.2017 | Physics and Astronomy
28.06.2017 | Physics and Astronomy
28.06.2017 | Health and Medicine