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
MicroRNA helps cancer evade immune system
19.09.2017 | Salk Institute
Ruby: Jacobs University scientists are collaborating in the development of a new type of chocolate
18.09.2017 | Jacobs University Bremen gGmbH
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...
Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.
Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
19.09.2017 | Event News
19.09.2017 | Physics and Astronomy
19.09.2017 | Power and Electrical Engineering