Infectious diseases, in which pathogens invade and colonize host cells, are responsible for one third of all mortality worldwide. Host cells use special proteins (immunoproteins) and other molecules to fight viral and bacterial invaders. The mechanisms by which immunoproteins enable cells to reduce bacterial loads and survive infections remained unclear until some physicists and biologists teamed up to unravel the mystery. They found that cells, amazingly, alter their physical properties (precisely, their stiffness) in a manner that reduces bacterial burden. Their work entitled, Actin polymerization as a key innate immune effector mechanism to control Salmonella infection, was published on Nov 24th, 2014 in the prestigious journal, PNAS (Proceedings of the National Academy of Sciences of the United States of America). This journal usually publishes "original research of exceptional importance".
The Creighton University physics department is significantly connected with this remarkable discovery. The main tool that led to the discovery is the optical stretcher and Creighton University was the 2nd in the world to have this tool, thanks to our own Dr Michael Nichols. He couched and mentored several graduates and undergraduates using novel biophysical tools including the optical stretcher. In fact, the co-first author on this recent PNAS paper, Dr Andrew Ekpenyong, who made the optical stretcher measurements that led to the discovery, first learnt optical stretching as a Master’s student here in the Creighton University physics department, supervised by Dr Nichols. We congratulate Dr Ekpenyong and the rest of the team of physicists and biologists (from the University of Cambridge, UK, and Technical University, Dresden, Germany), for this intriguing discovery. It is envisaged that their work will lead to new and better ways of treating infectious diseases.