We and all other organisms must constantly grapple with bacteria. Whether for a necessary symbiosis or an infection, carbohydrate structures on cell surfaces play an important role in the interactions between bacteria and organisms.
A team led by Antonio Molinaro at the University of Naples and Christian Hertweck at the Leibniz Institute for Natural Product Research and Infection Biology in Jena have now discovered an unusual carbohydrate structure without which the symbiosis between a bacterium and a fungus that affects rice plants is not stable. As the researchers report in the journal Angewandte Chemie, the bacterium probably requires this structure as camouflage for protection against the defense mechanisms of the fungus.
In gram-negative bacteria, lipopolysaccharide (LPS) carbohydrate structures are especially important for cell–cell interactions. LPS consists of a complex chain made of various saccharide molecules and a lipid that anchors the structure in the cell membrane. “Previous studies were limited to the role of LPS in the interaction of bacteria with animals or plants,” says Hertweck. “There is thus a sizeable knowledge gap with respect to interaction with other microbes.” The team has now examined a singular symbiosis: The fungus Rhizopus microsporus, which causes rice blight, inhibits root growth in rice plants, causing the plants to die. To achieve this, the fungus needs a partner—the bacterium Burkholderia rhizoxinica. The bacteria produce toxins needed by the fungus to damage the rice plants. The nutrients released by the dead plants are then used by both symbiotic partners.
“Until now the mechanism that allows the bacteria to survive within the fungal cells has remained a mystery,” says Hertweck. Now the team seems to be on the heels of a solution. “We have found an unusual polysaccharide, a chain of several galactose molecules, in the LPS of the bacterium,” says Herweck. “This pattern has not been seen before in this class of bacteria; however similar structures often occur in fungi.” The bacterium possibly mimics these structural elements of its host organism. The researchers infected fungi with mutated bacteria that did not contain these polysaccharides. In this case, the partners are not able establish a stable symbiosis. This becomes evident when the fungi are no longer able to produce spores.
“The special galactose sequence probably acts as a disguise for the bacterium,” opines Hertweck. “It is possible that it is thus not recognized as foreign, which keeps it safe from the defense mechanism of the fungus.”
Author: Christian Hertweck, Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie, HKI, http://www.hki-jena.de/index.php/0/1/107
Title: An Unusual Galactofuranose Lipopolysaccharide That Ensures the Intracellular Survival of Toxin-Producing Bacteria in Their Fungal Host
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201003301
20.11.2017 | Washington University in St. Louis
Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign
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
20.11.2017 | Life Sciences
20.11.2017 | Trade Fair News
20.11.2017 | Earth Sciences