Bacteria Uses Never-before-seen Method to Invade Tissue
Like something out of a horror movie, a new way that one type of bacteria invades tissue within a living organism has been identified by biologists from San Diego State University.
The study, published in Nature Communications, describes how a new species of bacteria, Bordetella atropi, invades its roundworm host. The name which comes from the Greek fate Atropos responsible for cutting the threads of life, is apt because the bacteria transforms into a long thread, growing up to 100 times the usual size of one bacterium in the span of 30 hours without dividing.
By altering the genes of B. atropi, the research team discovered that this invasive threading relies on the same genes and molecules that other bacteria use when they are in a nutrient-rich environment. However, these other bacteria only use this pathway to make subtly larger cells, whereas the B. atropi bacteria grows continuously.
Other bacteria often transform into threads, called filamentation, in response to dangerous environments or DNA damage. This lets them continue to grow in size, but delay cell division until they repair the damage inflicted by the stress.
Here, however, the researchers were the first to observe filamentation as a way of spreading from cell to cell in a living organism for a purpose other than the stress response. They believe that instead the new species is invading the host cells, detecting this rich environment and triggering filamentation in order to quickly infect more cells and access additional nutrients for their growth.
“We went from finding the worm in the ground, finding the bacteria, and carrying it all the way to the molecular mechanism of how the bacteria infects the worm,” explained Robert Luallen, biology professor and principal investigator of the study. “We’re seeing things that no one’s ever seen before.”
Though B. atropi does not infect humans, it is possible that human pathogens may also make use of its spreading mechanism. Separately, the nutrient-induced filamentation process might be used by other bacteria to form biofilms, which can coat the tubing of catheters and lead to complications for patients.
Source: EurekAlert!