title: Jamming prokaryotic cell-to-cell communications in a model biofilm.
abstract: We report on the physical parameters governing prokaryotic cell-to-cell signaling in a model biofilm. The model biofilm is comprised of bacteria that are genetically engineered to transmit and receive quorum-sensing (QS) signals. The model is formed using arrays of time-shared, holographic optical traps in conjunction with microfluidics to precisely position bacteria, and then encapsulated within a hydrogel that mimics the extracellular matrix. Using fluorescent protein reporters functionally linked to QS genes, we assay the intercellular signaling. We find that there isn't a single cell density for which QS-regulated genes are induced or repressed. On the contrary, cell-to-cell signaling is largely governed by diffusion, and is acutely sensitive to mass-transfer to the surroundings and the cell location. These observations are consistent with the view that QS-signals act simply as a probe measuring mixing, flow, or diffusion in the microenvironment of the cell.
authors.affiliation: Whitehead Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. timp0@alum.mit.edu
authors.forename: Winston
authors.initials: W
authors.lastname: Timp
authors.forename: Utkur
authors.initials: U
authors.lastname: Mirsaidov
authors.forename: Paul
authors.initials: P
authors.lastname: Matsudaira
authors.forename: Gregory
authors.initials: G
authors.lastname: Timp
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms; D002450:Cell Communication / Q000235:genetics*; D004058:Diffusion; D004867:Equipment Design; D019793:Fluorescein / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D005818:Genetic Engineering; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006696:Holography; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D044085:Microfluidics / Q000295:instrumentation; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis; D052898:Optical Tweezers; D011387:Prokaryotic Cells / Q000502:physiology*; D053038:Quorum Sensing / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D019793:Fluorescein