(4) There is no known system in QS

(4) There is no known system in QS. regions of the two Receiver strains are comparable. (A) A local region in a mixed biofilm where clusters of Sender cells, Receiver cells and WT Receiver cells merge. Sender cells are marked by P(red) and WT Receiver cells are marked by P(blue), where Pis a constitutive promoter. This is the same figure as Fig 3B. (B) Bright Rutaecarpine (Rutecarpine) field image of the same biofilm region as in A. (C) Relative cell density (Clog(I/I0)) of WT Receiver cell clusters and Receiver cell clusters (mean SEM, n = 3).(TIF) pone.0132948.s006.tif (1.4M) GUID:?CDBCF6C4-A7DE-42CE-B690-799E51A95F60 S7 Fig: The low QS response of Receiver cells did not decrease further as a function of increasing distance from the WT Receiver cells. (A) Receiver cells grown nearby WT cells (PReceiver cells with different distance from the border of WT cells are false colored with magenta (layer 1), cyan (layer 2) and yellow (layer 3). (B) Response (PReceiver cells (mean SD, n = 49 cells).(TIF) pone.0132948.s007.tif (817K) GUID:?32E99EF8-9C13-4BC2-B713-5770A7820426 S8 Fig: Fluorescence intensity of Pin and WT cells are comparable. (A) Snapshot of WT and cells grow in MSgg liquid culture. Pis shown in green. (B) Pfluorescence intensity in WT and cells (mean SEM, n = 20 cells).(TIF) pone.0132948.s008.tif (2.4M) GUID:?71C722E3-4D01-49E8-A8EB-6DEB723B1223 S1 Table: List of strains. (DOCX) pone.0132948.s009.docx (19K) GUID:?799273D5-C0B1-412B-883D-E97D0B759AF6 S1 Text: Supplementary methods (DOCX) pone.0132948.s010.docx (30K) GUID:?E26EF3E4-4059-49F4-A6C3-4C91FCBC5CC6 Data Availability StatementAll relevant data are within the paper and its Supporting Information files. Abstract Bacteria predominantly reside in microbial communities known as biofilms, where cells are encapsulated and protected by the extracellular matrix (ECM). While all biofilm cells benefit from Rabbit Polyclonal to RPLP2 the ECM, only a subgroup of cells carries the burden of producing this public good. This dilemma provokes the question of how these cells balance the cost of ECM production. Here we show that ECM producing cells have a higher gene expression response to quorum sensing Rutaecarpine (Rutecarpine) (QS) signals, which can lead to a private benefit. Specifically, we constructed a synthetic quorum-sensing system with designated Sender and Receiver cells in biofilms [9,10] (Fig 1A). Those ECM producer cells are clearly burdened with a cost at a time of environmental stress and high cell density. This cost is evident by the observation that an ECM-deficient strain can outcompete the ECM producing strain in a mixed culture [11]. However, all cells within the biofilm, even those that do not contribute to ECM production, are believed to benefit from the ECM protection [12C14]. This provokes the question of how the subpopulation of cells that are burdened with ECM production can be sustained within the biofilm community [11,15C19]. It has been argued that expression of ECM by a subpopulation of cells may constitute a primitive form of altruism in bacteria [10] (Fig 1B). Here we Rutaecarpine (Rutecarpine) investigated whether ECM producers could also enjoy a private benefit, countering the cost of this public good production (Fig 1B). Open in a separate window Fig 1 Cost-benefit dilemma for ECM producers in biofilms.(A) In biofilms, only a subgroup of cells produces and secretes ECM. However, once secreted, ECM benefits all cells, including non-producers. The bottom picture is the top view of a three-day-old biofilm. (B) ECM producers carry a higher cost than non-producers due to production of ECM. Will these producers accordingly get a higher benefit from ECM or Rutaecarpine (Rutecarpine) not? (C) An orthogonal (inert) synthetic QS system was constructed in study indicated that quorum sensing molecules could transiently associate with the ECM [24]. Therefore, QS signals may be locally concentrated by the ECM, increasing their availability to cells. However, it is unclear if the transient association.