"It's a significant addition to the short list of defenses that animals use to protect themselves against toxin-induced sepsis," said Peter Armstrong, professor of molecular and cellular biology at UC Davis and senior author on the paper.
Even with modern antibiotics, septic shock from bacterial infections afflicts about 300,000 people a year in the U.S., with a mortality rate of 30 to 50 percent. Septic shock is caused by Gram-negative bacteria, which release a toxin called lipopolysaccharide or endotoxin. In small amounts, lipopolysaccharide triggers inflammation. When infections with these bacteria get out of hand, lipopolysaccharide courses through the bloodstream, causing catastrophic damage to organs and tissues.
These toxins cause disease in a variety of animal species — lipopolysaccharide is also toxic to both horseshoe crabs and lobsters, separated from humans by hundreds of millions of years of evolution. In humans and other mammals, blood clots quickly form from a mix of specialized blood cells and protein fibers. Arthropods like horseshoe crabs and lobsters can also form clots in response to injury, with a different mix of cells and proteins.
Clots protect and help to seal wounds, prevent blood or body fluids from leaking out and form a physical barrier that entangles and blocks bacteria from entering the body. The new study shows that they also actively soak up lipopolysaccharide, reducing its release from the wound site into the body, where it could cause disease or even death.
Armstrong's laboratory had previously developed fluorescent labels to show that a lipopolysaccharide-like molecule is present in chloroplasts, structures inside cells of green plants that carry out photosynthesis and are thought to be descended from bacteria. As he also studies the role of blood clots in resisting infections, Armstrong decided to test the same techniques on blood clots that had been exposed to bacteria or to bacterial lipopolysaccharide. The fluorescent probes lit up the clots, showing that the clot fibers bound lipopolysaccharide to their surfaces.
"I was ecstatic," Armstrong said. "It was one of those moments that makes the rest of the slogging worthwhile."
Armstrong and colleagues Margaret Armstrong at UC Davis and Frederick Rickles at George Washington University looked at clots of blood, or its equivalent, from humans, mice, lobsters and horseshoe crabs. In all four species, they found that fluorescently tagged lipopolysaccharide was bound to the fibers of the blood clot. The toxin was too tightly attached to be readily removed by chemical treatments that remove weakly bound macromolecules from proteins.
During a sabbatical leave in the laboratory of Dr. Bruce Furie at Beth Deaconess Medical Center and Harvard University, Armstrong was also able to film clots in blood vessels of live mice and showed that these in vivo clots took up lipopolysaccharide in real time. These in vivo experiments, he said, confirm the bench-top observations and offer new insights into the pathology of sepsis.
One of the deadly consequences of septic shock is disseminated intravascular coagulation, when blood clots form rapidly throughout the body. But the new results suggest that on a small and local scale, this might be part of a protective mechanism against sepsis — these intravascular clots can soak up quantities of lipopolysaccharide from the blood. They also show that rather than being a simple physical barrier, blood clots play an active and dynamic role in protecting the body from infections.
Parts of the research were carried out at the Woods Hole Marine Biological Laboratory. The work was funded by a grant from the National Science Foundation.
About UC DavisFor more than 100 years, UC Davis has been one place where people are bettering humanity and our natural world while seeking solutions to some of our most pressing challenges. Located near the state capital, UC Davis has more than 33,000 students, over 2,500 faculty and more than 21,000 staff, an annual research budget of nearly $750 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science. It also houses six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.
Andy Fell, UC Davis News Service, (530) 752-4533, email@example.com
Andy Fell | EurekAlert!
Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care
Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses