RT Journal Article
SR Electronic
T1 Accumulation of dead cells from contact killing facilitates coexistence in bacterial biofilms
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.04.03.024158
DO 10.1101/2020.04.03.024158
A1 Gabi Steinbach
A1 Cristian Crisan
A1 Siu Lung Ng
A1 Brian Hammer
A1 Peter Yunker
YR 2020
UL http://biorxiv.org/content/early/2020/04/05/2020.04.03.024158.abstract
AB Bacterial communities govern their composition using a wide variety of social interactions, some of which are antagonistic. Many antagonistic mechanisms, such as the Type VI Secretion System (T6SS), require killer cells to directly contact target cells. The T6SS is hypothesized to be a highly potent weapon, capable of facilitating the invasion and defense of bacterial populations. However, we find that the efficacy of the T6SS is severely limited by the material consequences of cell death. Through experiments with Vibrio cholerae strains that kill via the T6SS, we show that dead cell debris quickly accumulates at the interface that forms between competing strains, preventing contact and thus preventing killing. While previous experiments have shown that T6SS killing can reduce a population of target cells by as much as one-million-fold, we find that as a result of the formation of dead cell debris barriers, the impact of T6SS killing depends sensitively on the initial concentrations of killer and target cells. Therefore, while the T6SS provides defense against contacting competitors on a single cell level, it is incapable of facilitating invasion or the elimination of competitors on a community level.