An SGM press release said the findings could allow us to better protect food from contamination by these harmful bacteria, as well as understand how they manage to cause disease.
Bile is secreted into the small intestine and exerts an antibacterial effect by disrupting bacterial membranes and damaging bacterial DNA, the release said. While bile is a human defense mechanism, Hamner and his colleagues at MSU and the University of New England found that some bacteria such as Escherichia coli O157:H7 -- an important food-borne pathogen known as E. coli -- have evolved to use the signal to their advantage. These bacteria use the presence of bile as a signal to tell them that they are in the intestine which allows them to adapt and prepare to cause disease.
Hamner's team found that bile causes the bacteria to switch on genes needed to increase iron uptake.
"This is useful in iron-scarce environments -- such as the small intestine -- as iron is an essential nutrient for bacterial growth. By increasing its chances of absorbing iron, the bacterium is maximizing its survival chances," Hamner explained.
E. coli O157:H7 primarily infects the large intestine, and this study provides one explanation why this is the case.
"We found that bile causes the bacteria to turn off genes that promote tight attachment to host cells. Bile may effectively prevent these bacteria from latching onto the epithelial cells that line the small intestine," Hamner suggested.
As bacteria move further down the digestive tract towards the large intestine, the concentration of bile decreases.
"The reduced concentration of bile in the large intestine may then be a signal for the bacteria to switch on their ability to attach to epithelial cells and to prepare to secrete toxins," Hamner said.
Studying the conditions that make these bacteria more likely to attach themselves to cells could help reduce outbreaks of food poisoning.
"By learning how the bacteria attach to food surfaces such as spinach leaves or to host tissues such as the lining of the intestine, we hope to better be able to protect food sources from contamination by these bacteria. Studying how these bacteria interact with hosts such as humans or cows could teach us how to interfere with the way that these bacteria cause disease," Hamner said.
The Society for General Microbiology is the largest microbiology society in Europe, and has over 5,500 members worldwide. Its spring meeting was held March 29 through April 1.
Evelyn Boswell | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy