Even though we have lost much of our fear of tuberculosis in the industrialized countries, according to the WHO about 2 mio. people worldwide die each year of this infectious disease. Researchers at the University of Leeds have now discovered a carbohydrate with an unusual structure in the cell walls of Mycobacterium tuberculosis, the bacterium that causes tuberculosis. This could be a new starting point for pharmaceutical research.
The main component of the cell walls of mycobacteria is a lipoarabinomannan (LAM), a molecule consisting of a branched segment made of many sugar building blocks, which is anchored to the cell wall by a fat-like segment. The sugars involved are almost exclusively arabinose and mannose. LAM plays an important role in infection, because it helps the mycobacteria to invade macrophages, dampen the immune response, and protect the invader from oxidation. Researchers working with Achim Treumann have recently discovered that some of the mannose end groups on the outside of the molecule carry another type of sugar building block, a so called methylthiopentofuranose. This type of sugar consists of five carbon atoms (pento) and one of its usual five oxygen atoms is replaced by a sulfur atom (thio), which is also attached to a methyl group (-CH3). This discovery is astonishing because this is the first time that a methylthiosugar has been identified as a component of a polysaccharide. The sulfur atom may be responsible for the protection from oxidation provided by LAM.
However, this sugar is astonishing for another reason: it has an unexpected configuration. Like many sugars, it contains a five-membered ring made of four carbon atoms and one oxygen atom (furanose). There are eight different possibilities for the exact configuration of such a five-membered ring, because each of the four carbon atoms is attached to a further group of atoms, which could lie above or below the surface of the ring. Treumann and his co-workers took on the task of synthesizing all of the eight variations. NMR spectroscopic comparison of the eight sugars with the "original" natural form then allowed the team to identify the correct structure. In this case it has the "xylo" configuration. This is unusual, since sugars with the xylo configuration are usually only found in plants, not in bacteria.
Jaida Harris | alfa
Closing the carbon loop
08.12.2016 | University of Pittsburgh
Newly discovered bacteria-binding protein in the intestine
08.12.2016 | University of Gothenburg
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences