University of Bath and University of Exeter scientists have come up with a novel technique to make movies of bacteria infecting their living hosts.
The researchers claim that, to date, most studies of bacterial infection have been done after the death of the infected organism, and that they are the first scientists who have been successful in following the progress of infection in real-time with living organisms.
They used developing fruit fly embryos as a model organism, injecting fluorescently tagged bacteria into the embryos and observing their interaction with the insect's immune system using time-lapse confocal microscopy.
The team say that they can also tag individual bacterial proteins to follow their movement, and determine their specific roles in the infection process.
The researchers are hoping to use this system in the future with human pathogens, such as Listeria and Trypanosomes.
According to them, observing how these bacteria interact with the immune system may prove helpful in gaining a better understanding of how they cause an infection, and eventually lead to better antibacterial treatments.
Dr. Will Wood, Research Fellow in the Department of Biology and Biochemistry at the University of Bath, said: "Cells often behave very differently once they have been taken out of their natural environment and cultured in a petri dish. In the body, immune surveillance cells such as hemocytes (or macrophages in vertebrates) are exposed to a battery of signals from different sources. The cells integrate these signals and react to them accordingly."
Dr. Wood added: "Once these cells are removed from this complex environment and cultured in a petri dish these signals are lost. Therefore it is really important to study whole organisms to fully understand how bacteria interact with their host."
Dr. Nick Waterfield, co-author on the study and Research Officer at the University of Bath, said: "To be able to film the microscopic battle between single bacterial cells and immune cells in a whole animal and in real time is astounding. It will ultimately allow us to properly understand the dynamic nature of the infection process."
Professor Richard Ffrench-Constant, Professor of Molecular Natural History at the University of Exeter, added: "For the first time this allows us to actually examine infection in real time in a real animal - it's a major advance!"
Funded by the Wellcome Trust and the Biotechnology and Biological Sciences Research Council, the study has been published in PLoS Pathogens.