IGEM:IMPERIAL/2007/Projects/Biofilm Detector/Notes

=Infector Detector: Notes=

 Introduction Specifications Design Modelling Fabrication Testing Data Analysis Validation</li> Notes</li> References</li> </ul> <br style="clear:both">

Making Biofilm

 * Freshly-grown growth-phase E. coli ZK1056 culture is added to sterile medium to a concentration of 5 × 107 cells/mL.
 * Round 15 mm sterile glass coverslips are placed upright in the wells of a 24-well plate with sterile plastic stands
 * Add 1 mL of E. coli solution to each well.
 * The 24-well plate is immediately covered and transferred to a 30 °C incubator.

AHL produced in biofilms:
(Notes on the journal modeling AHL production in biofilms of the same bacterial population) AHL synthesis is subject to autoinduction in which production of AHLs operates as a positive feedback loop. Assumptions made in the model:
 * All bacterial cells are physiologically identical with regard to size, shape and permeability of the cell membrane, as well as production and degradation rates of the signalling molecules
 * Bacterial population exhibit a standard logistic growth pattern
 * No metabolic or physiological lag is assumed
 * At very low Cbc, the net rate of AHL production, h(Cbc), is assumed to be determined solely by the difference between basal production, Bp, and degradation of AHLs
 * Degradation of AHLs is proportional to the concentration of AHL and occurs at a rate d*Cbc

Not considered in the model: permeability constant a, which is characteristic of the bacterial cell membrane, the diffusability of a given AHL, and the viscosity of the cell and the biofilm

Conclusions from the model: high concentrations of AHL inside cells could be achieved at very low population densities. Rapid rise in AHL concentration early in population growth, followed by a plateau, followed by another rise to a second plateau

Biofilm detection using AHL as signals
http://aem.asm.org/cgi/reprint/67/2/575