If these tiny, microscopic organisms are to survive in these environments, they need to be able to rapidly detect changes in their surroundings and react to them. Scientists at the Johannes Gutenberg University of Mainz are currently investigating how bacteria manage to pass information on their environment across their membranes into their cell nuclei.
"The sixty-four-thousand- dollar question is how signals are transmitted across the cell membrane," explains Professor Gottfried Unden of the Institute of Microbiology and Vinology. Working in collaboration with the Max Planck Institute for Biophysical Chemistry in Göttingen, his research group has demonstrated that structural alterations to membrane-based sensors play a major role in the transfer of signals.
Some bacteria possess more than 100 different sensors that they use to form a picture of their environment. These sensors can show, for example, whether nutrient substrates and/or oxygen are present in the immediate neighborhood of the cell and what the external status of temperature and light is like. These sensors are mainly located in the cell membrane, i.e., the layer separating bacteria cells from the environment. From there they then transmit signals into the cell nucleus. Thanks to the development of new methods of isolating these sensors and of other innovative techniques, it is now possible to discover how all this works. The researchers in Mainz have also managed to modify a sensor that detects an important bacterial substrate so that it can be analyzed making use of new spectroscopic techniques.
"This is the first time that solid-body nuclear magnetic resonance (NMR) spectroscopy has been used to investigate large membrane proteins," stated Professor Unden. In addition to this functional analysis, the structural analysis undertaken by the biophysicist team in Göttingen headed by Professor Marc Baldus has identified important details of the signal transmission process: a stimulus molecule – carbonic acid in this case – binds to a part of the sensor that protrudes from the cell. This appears to result in dissolution of the ordered structure of that segment of the sensor within the cell that is in non-stimulated status. It seems that it is this plasticity that elicits the subsequent activation of the enzymatic reaction cascade within the cell. This results in the cellular response, which, for example, can take the form of neosynthesis of enzymes or the development of protective mechanisms.
In addition to the new findings on signal transmission published in Nature Structural and Molecular Biology, the microbiologists of Mainz University have discovered a previously unknown and exceptional method of signal detection employed by the same sensor (designated DcuS), which they discuss in an article in the Journal of Biological Chemistry. This shows that bacteria react not only to their extracellular environment, but also to the intracellular situation. It is becoming apparent that it is not the sensors alone that detect stimuli. A second stimulus detection pathway is represented by the transport system that channels substrates into the cell. Once the substrate – carbonic acid – has been taken up, the transporter notifies the sensor of this. Prof. Unden added, "We have been able to identify that segment of the transporter that is responsible for the control of sensor functioning. The transporter is of fundamental importance for the function of the sensor. Without the transporter, the sensor does not work correctly and is constantly in activated status," explained Professor Unden, who suspects that this function-related feedback on metabolic and transport activity is often more important for a cell than information concerning concentrations only.
Prof Dr Gottfried Unden | alfa
Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt
Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Trade Fair News
16.01.2017 | Automotive Engineering
16.01.2017 | Life Sciences