Researchers from Boston University’s Slone Epidemiology Center have found that exposure to pseudoephedrine, a decongestant found in many cough-and-cold and allergy medications, has been common among U.S. children, especially those under the age of two years who are at the highest risk for toxicity and for whom safe dosing recommendations are lacking. These findings appear
Full Post: Exposure to pseudoephedrine common among young children
Bacteria can occur almost anywhere on earth and exist under the most varying conditions. 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.
Scientists from the Scripps Research Institute have discovered the key chemical that signals Bacillus anthracis, the bacterium that causes anthrax, to become lethal. This finding opens up new avenues of exploration for the development of treatments for bacterial infections. The study was published in the November 21 edition of the journal PLoS Pathogens . The
Full Post: Scientists identify blood component that turns anthrax bacteria virulent
MIT engineers have developed carbon nanotubes into sensors for cancer drugs and other DNA-damaging agents inside living cells. The sensors, made of carbon nanotubes wrapped in DNA, can detect chemotherapy drugs such as cisplatin as well as environmental toxins and free radicals that damage DNA. “We’ve made a sensor that can be placed in living
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A multidisciplinary team at the Massachusetts Institute of Technology (MIT) has developed carbon nanotubes that can be used as sensors for cancer drugs and other DNA-damaging agents inside living cells. The sensors, made of carbon nanotubes wrapped in DNA, can detect chemotherapy drugs such as cisplatin as well as environmental toxins and free radicals that
Full Post: Nanotubes sniff out cancer agents in living cells
An important piece in the diabetes puzzle which has perplexed scientists for decades has been uncovered by a Sydney PhD student at Sydney’s Garvan Institute of Medical Research. The novel finding by Freddy Yip has revealed how insulin works and brings researchers one step nearer to understanding just how insulin prompts fat and muscle cells
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Many older adults want to remain active and independent for as long as possible. Seniors want to age in their own homes and avoid moving to institutions or nursing homes. University of Missouri researchers are using sensors, computers and communication systems, along with supportive health care services to monitor the health of older adults who
Full Post: Health-monitoring technology helps seniors live at home longer --------------------------------------------------------------------------------------------