Project description:The bacterial type VI secretion system is a widespread secretion mechanism important for competition in many Gram-negative bacteria. Killing and lysing of competing bacteria can provide advantages such as nutrients or acquisition of new genes by DNA uptake. Here, we show that T6SS-dependent lysis of prey cells by the naturally competent Acinetobacter baylyi results in extensive filamentation of a significant subpopulation of A. baylyi cells. This is dependent on the release of genomic DNA from the lysed prey cells and its uptake by the competence system of A. baylyi. Single-cell level analysis using live-cell imaging shows that filamentous A. baylyi cells appear at the interface between the species. The analysis of A. baylyi transcriptome and the response of transcriptional reporters suggest that the uptake of genomic DNA results in a highly upregulated SOS response, which often leads to the cell division arrest. Using competition experiments, we show that the parental strain is outcompeted by a strain lacking the DNA uptake machinery because such mutant shows no SOS response-dependent cell division arrest. Our data suggest that the cost of SOS-response may drive selection of decreased DNA uptake in T6SS positive bacteria.
Project description:The goals of this study are to use SWATH-MS to detect bacterial proteomic profiles of wild-type Acinetobacter baylyi ADP1, and its protein response under the exposure of disinfectants, including chloramine and free chlorine. The concentrations of disinfectants were 10 mg/L. The group without dosing disinfectant was the control group. Each concentration was conducted in triplicate. By comparing the proteomic profiles of experimental groups and control group, the effects of disinfectants on translational levels can be revealed.
