Researchers from the University of Groningen have clarified the structure of an enzyme that disturbs the communication processes between bacteria. By doing so they have laid the foundations for a new method of tackling bacterial infections such as cystic fibrosis. An article on the structure and function of the so-called quorum-quenching acylase was published on 21 December 2009 in the online edition of the Proceedings of the National Academy of Sciences (PNAS).
Although bacteria are simple single-celled organisms, they are capable of communicating with each other. Bacteria talk to each other by exchanging tiny hormone-like signal molecules. By means of this process of 'quorum sensing', the activities of a large group of bacteria are synchronized. Thus bacteria can adapt quickly to changes in their environment such as the running out of nutrients or the arrival of rival microorganisms.
The production of factors that determine the virulence of a bacterium is also controlled by these signal molecules. This enables bacteria to remain invisible to the immune system in the early stages of infection. As soon as the group of informed bacteria -- the quorum -- is sufficiently large, the attack on the infected host is initiated by starting up the production of toxins and other virulence factors.
Science & Technology
© Max Planck Institute for Extraterrestrial Physics
Herschel-PACS images of the ‘GOODS-N’ field in the constellation of Ursa Major at far-infrared wavelengths of 100 and 160micrometres.
Herschel-PACS images of the ‘GOODS-N’ field in the constellation of Ursa Major at far-infrared wavelengths of 100 and 160micrometres.
In the mid 1990's, scientists analyzing data from NASA's COBE spacecraft discovered faint radiation in the far-infrared part of the electromagnetic spectrum that reaches earth with the same intensity from all directions in space. Immediately, they suspected it to be the aggregate emission of many distant galaxies in the early universe, releasing the same amount of energy in the far-infrared as reaches us in visible light from similarly distant galaxies.
Whereas visible light tells us about the stars in galaxies, the far-infrared is emitted by cold dust that is hiding the newly formed stars. Identifying these surprisingly numerous dusty galaxies has proven difficult, though. Space telescopes are needed to detect far-infrared emission, because it is absorbed by the Earth's atmosphere. Previous infrared space telescopes have detected far-infrared light from only the brightest of the galaxies forming this cosmic background. To glean any information about the fainter objects, astronomers had to rely on indirect evidence based on shorter wavelength radiation.
© NASA/JPL
Artist's rendering depicts the Voyager 2 spacecraft as it studies the outer limits of the heliosphere - a magnetic 'bubble' around the Solar System that is created by the solar wind. Scientists observed the magnetic bubble is not spherical, but pressed inward in the southern hemisphere.
Artist's rendering depicts the Voyager 2 spacecraft as it studies the outer limits of the heliosphere - a magnetic 'bubble' around the Solar System that is created by the solar wind. Scientists observed the magnetic bubble is not spherical, but pressed inward in the southern hemisphere.
The cloud is called the "Local Fluff." It's about 30 light-years wide and holds a wispy mix of hydrogen and helium atoms, according to a NASA statement released today. Stars that exploded nearby, about 10 million years ago, should have crushed the Fluff or blown it away.
So what's holding the Fluff in place?
"Using data from Voyager, we have discovered a strong magnetic field just outside the solar system," explained Merav Opher, a NASA Heliophysics Guest Investigator from George Mason University. "This magnetic field holds the interstellar cloud together ["The Fluff"] and solves the long-standing puzzle of how it can exist at all."
The Fluff is much more strongly magnetized than anyone had previously suspected," Opher said. "This magnetic field can provide the extra pressure required to resist destruction."
A team of researchers working in a high containment laboratory at the Centers for Disease Control and Prevention in Atlanta, GA, have solved a fundamental mystery about smallpox that has puzzled scientists long after the natural disease was eradicated by vaccination.: they know how it kills us. In a new research report appearing online in The FASEB Journal, researchers describe how the virus cripples immune systems by attacking molecules made by our bodies to block viral replication.
This discovery fills a major gap in the scientific understanding of pox diseases and lays the foundation for the development of antiviral treatments, should smallpox or related viruses re-emerge through accident, viral evolution, or terrorist action.
"These studies demonstrate the production of an interferon binding protein by variola virus and monkeypox virus, and point at this viral anti-interferon protein as a target to develop new therapeutics and protect people from smallpox and related viruses," said Antonio Alcami, Ph.D., a collaborator on the study from Madrid, Spain. "A better understanding of how variola virus, one of the most virulent viruses known to humans, evades host defenses will help us to understand the molecular mechanisms that cause disease in other viral infections."
This discovery fills a major gap in the scientific understanding of pox diseases and lays the foundation for the development of antiviral treatments, should smallpox or related viruses re-emerge through accident, viral evolution, or terrorist action.
"These studies demonstrate the production of an interferon binding protein by variola virus and monkeypox virus, and point at this viral anti-interferon protein as a target to develop new therapeutics and protect people from smallpox and related viruses," said Antonio Alcami, Ph.D., a collaborator on the study from Madrid, Spain. "A better understanding of how variola virus, one of the most virulent viruses known to humans, evades host defenses will help us to understand the molecular mechanisms that cause disease in other viral infections."
The sun is showing signs of life. There are no fewer than five active regions on the sun's surface, shown here in an extreme ultraviolet photo taken this morning by the Solar and Heliospheric Observatory (SOHO):
Each circle contains a sunspot or proto-sunspot belonging to new Solar Cycle 24. After two years of record-low sunspot numbers and many month-long stretches of utter quiet, this is a notable outbreak. Whether it heralds a genuine trend or merely marks a temporary, statistical uptick in activity remains to be seen.
© SOHO/Spaceweather.com
© The American Chemical Society
A test strip shows a visible color change indicating the presence of pesticides, and advance toward a dipstick test for foods and beverages.
A test strip shows a visible color change indicating the presence of pesticides, and advance toward a dipstick test for foods and beverages.
© NASA
Artist's rendition of a brown dwarf and its moon orbiting a triple star system
Artist's rendition of a brown dwarf and its moon orbiting a triple star system
"We have found two brown dwarf-sized masses around an ordinary star, which is very rare," said Alex Wolszczan, Evan Pugh professor of astronomy and astrophysics, Penn State and lead scientist on the project.
The star, BD +20 2457, is a K2 giant -- an old bloated star nearing the end of its life. Seeing a pair of brown dwarfs around a K-type giant is a first for astronomers and offers a unique window into how they can be produced. The researchers from the Torun Center for Astronomy, Poland and the Center for Exoplanets and Habitable Worlds, Penn State report their findings in the current issue of the Astrophysical Journal.
An appeals court on Tuesday ordered Microsoft to stop selling Microsoft Word 2007 and other Office 2007 products by Jan. 11 because the software infringes on a patent held by a Canadian company. The judge also hit Microsoft with a $290 million fine.
In ruling, the U.S. Court of Appeals struck down Microsoft's appeal of a lower court's finding that Word 2007, the most current version of the product, infringes on a patent held by Toronto-based i4i Inc.
I4i originally sued Microsoft in 2007, claiming that an XML editor built into Word steps on its patent. In August, the U.S. District Court for Eastern Texas found in favor of i4i, prompting Microsoft's appeal. The appeals court on Tuesday upheld the Texas decision.
In ruling, the U.S. Court of Appeals struck down Microsoft's appeal of a lower court's finding that Word 2007, the most current version of the product, infringes on a patent held by Toronto-based i4i Inc.
I4i originally sued Microsoft in 2007, claiming that an XML editor built into Word steps on its patent. In August, the U.S. District Court for Eastern Texas found in favor of i4i, prompting Microsoft's appeal. The appeals court on Tuesday upheld the Texas decision.
© Wikimedia Commons
A fossil cast of what's believed to be a Sinornithosaurus is seen at the American Natural History museum in New York in this file photo.
A fossil cast of what's believed to be a Sinornithosaurus is seen at the American Natural History museum in New York in this file photo.
Sinornithosaurus was petite as dinosaurs go - think of a turkey with teeth. It ran with a tough crowd, though; it was cousin to the oh-so-scary velociraptor of Jurassic Park fame.
Paleontologist David Burnham from the University of Kansas and a Chinese colleague were puzzled by a 125-million-year-old Sinornithosaurus fossil in a museum - specifically, by its upper teeth.
"We finally realized that we're looking at the outside of these teeth and they're grooved," Burnham recalls. "And we both looked at each other and thought,
'What? Why would an animal have grooved teeth?' "
Starting from the end of November, Queen Mary's Particle Physics Research Centre is the sole recipient of the T2K experiment data. The T2K Collaboration is a 500-strong alliance of scientists in 12 countries, who have come together to investigate the ghostly neutrino.
Physicist Dr Francesca Di Lodovico said: "Trillions of neutrinos pass through our bodies every second, but you don't notice; they pass through space and the Earth with almost no effect. This makes neutrinos very difficult to study and yet they are thought to play a fundamental role in the formation of the Universe and understanding where we came from."
Neutrinos come from outer space, either shot out from the Sun, or left over from the Big Bang. But despite their abundance, techniques to understand their nature have only been developed in the last few decades, giving surprising results.
Physicist Dr Francesca Di Lodovico said: "Trillions of neutrinos pass through our bodies every second, but you don't notice; they pass through space and the Earth with almost no effect. This makes neutrinos very difficult to study and yet they are thought to play a fundamental role in the formation of the Universe and understanding where we came from."
Neutrinos come from outer space, either shot out from the Sun, or left over from the Big Bang. But despite their abundance, techniques to understand their nature have only been developed in the last few decades, giving surprising results.
