How Salmonella Organizes its Invasion
News Jun 08, 2015
Salmonella bacteria are the leading cause of food borne illness in the EU. Part of what makes them so successful is their ability to invade our bodies, overcoming our natural defences. Understanding how they do this could lead to new ways of preventing their invasion.
Image: Institute of Food Research
Most Salmonella infections result in gastroenteritis, when the bacteria invade the epithelial cells lining our gut. However, under certain conditions, Salmonella can subsequently cause a potentially lethal systemic typhoidal infection when they invade the underlying immune cells. The invasion of epithelial cells and immune cells are controlled by two separate gene clusters called Salmonella Pathogenicity Islands 1 and 2 (SPI1, SPI2) respectively.
Now Dr Arthur Thompson and colleagues from the Institute of Food Research have shown how certain factors within Salmonella help to coordinate the deployment of SPI1 and SPI2.
The control system involves two proteins (RpoS and DksA) and ppGpp, an alarmone. Alarmones are molecules that bacteria produce in response to extreme environments, such as in the harsh environment of the gut. In conjunction with each other, these components help to coordinate when and where SPI1 and SPI1 genes are expressed, in phases that match the steps in Salmonella’s infection strategy.
“We’ve shown how RpoS, DskA and ppGpp modulate the distribution and activity of RNA polymerase to allow the phased expression of SPI1 and SPI2” said Dr Thompson of the IFR, which is strategically funded by the Biotechnology and Biological Sciences Research Council.
“This helps answer a longstanding and important question of how expression of SPI1 and SPI2 genes are synchronised which can result in a potentially fatal infection”.
Computation and Chemistry Combine to Create World-First Auxetic ProteinNews
A team of chemists at the University of California, San Diego (UCSD) has now designed a two-dimensional protein crystal that toggles between states of varying porosity and density. This is a first in biomolecular design that combined experimental studies with computation done on supercomputers. The research, published in April 2018 in Nature Chemistry, could help create new materials for renewable energy, medicine, water purification, and more.
Growing Issue of Pesticide Resistance - Action Needed!News
A review has found that large-scale studies are required to test new approaches for slowing pest resistance as herbicide and pesticide resistance is a growing problem.READ MORE
Fructose Formula Poses Risk to Babies With Metabolic DisorderNews
Babies with inherited intolerance of fructose face a risk of acute liver failure if they are fed certain widely available formulas containing fructose, pediatricians and geneticists are warning. Baby formula manufacturers should remove fructose or sucrose, or explicitly label their products to allow parents to avoid those sweeteners if necessary, the doctors say.