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Engineered bidirectional communication mediates a consensus in a microbial consortium

Engineered bidirectional communication mediates a consensus in a microbial consortium. Presented by: Iman Mirrezaei. Outline. Introduction Problem definition Methods Experiments. Why am I still Sick . 170 Million American have Chronic disease What is Chronic bacterial disease?

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Engineered bidirectional communication mediates a consensus in a microbial consortium

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  1. Engineered bidirectional communication mediates a consensus in a microbial consortium Presented by: ImanMirrezaei

  2. Outline • Introduction • Problem definition • Methods • Experiments

  3. Why am I still Sick • 170 Million American have Chronic disease • What is Chronic bacterial disease? • Infection of bones • Make people suffer and make people die • The real number are staggering • 550,000 deaths annually • 30x the number of Aids patients • Equal to the number of cancer death • $94 Billion in medical costs

  4. Biofilm • A biofilm is any group of microorganisms • The ability to manipulate these films would enable controlled studies of microbial ecosystem dynamics Staphylococcus aureusbiofilm

  5. BioFilm formation • Reversible Adsorption of Bacteria (sec.) • Irreversible attachment of bacteria (sec.-min.) • Growth and division of bacteria (hrs.-days) • Exopolymer production and BioFilm formation (hrs.-days) • Attachment of other organism to BioFilm( days- months)

  6. BioFilm relationship • The BioFilm could maintain different relationship with the hosts: • Mutualism: both benefit • Commensalism: one benefit one unaffected • Parasitism: one benefit, one harmed • Competition: neither benefit • Neutralism: both unaffected

  7. BioFilms properties • Difficult to be Removed and Killed • Function as a single organism

  8. Microbial consortia form • Microbial consortia form generate a function that none is capable of alone. • global food chain to human weight gain • A microbial consortium is two or more microbial groups living symbiotically

  9. Problem definition • Two colocalized populations of Escherichia coli converse by exchanging lactone signals. • This consensus function can be considered a logical AND gate • The ability to manipulate and control these films Escherichia Coli

  10. Engineered circuits • Engineered circuits have been used to control the behavior of single cells and cell populations • Engineered communication • Broadcasting • Small-molecule signals

  11. Experiments Requirements • Engineered circuits have been used to control the behavior of single cells and cell populations in both time and space • Escherichia coli Bacterium

  12. The MCC “Signaling Network” • Components of the LasI/LasR and RhlI/RhlR quorum sensing systems found in Pseudomonas aeruginosa, that forms a biofilm in the lungs of cystic fibrosis patients cystic fibrosis patients

  13. The MCC “Signaling Network”

  14. Modeling to Minimize Crosstalk • Minimize densities for consensus activation, maximize densities for isolation activation • Positive feedback loop • Need C4HSL for LasI and 3OC12HSL; need 3OC12HSL for RhlI and C4HSL (minimize crosstalk signal)

  15. Liquid Culture • GFP( target gene) in both • Separate chambers with passage of small molecules • Responses over 100-fold greater with communication Circuit A (with B) Circuit B (with A) Circuit B (alone) Circuit A (alone)

  16. Solid Culture • Cell types embedded separately in solid medium • Media placed in contact • Fluorescence decreases with distance from interface • Circuit A slower growth

  17. Increasing fluorescence from increasing concentration of signaling molecule

  18. Biofilms (consortium) • Circuit A – green (yellow); Circuit B – red (cyan) • Grow together and display MCC function (≥6dys) • No significant fluorescence separately

  19. Biofilm Communication in Nature • Quorum sensing to coordinate biofilm formation • Biofilm disruption • Fundamental Applications • Integrate cells sensing different stimuli (temp, pH, ...) • More communication partners • Communication other than quorum

  20. Applied Applications • Mixed-culture batch reactors require quorum of each • Disrupt pathogenic BioFilms • Enzyme-prodrug pair; inactive toxin fragments • Materials synthesis • Surveillance for environmental changes • Epidemiology, material degradation

  21. References: • 1. Hooper LV, Midtvedt T, Gordon JI (2002) Annu Rev Nutr 22:283–307. • 2. Kato S, Haruta S, Cui ZJ, Ishii M, Igarashi Y (2005) Appl Environ Microbiol 71:7099–7106. • 3. Kleessen B, Blaut M (2005) Br J Nutr 93(Suppl 1):S35–S40. • 4. Macfarlane S, Woodmansey EJ, Macfarlane GT (2005) Appl Environ Microbiol 71:7483–7492. • 5. Mishra S, Jyot J, Kuhad RC, Lal B (2001) CurrMicrobiol 43:328–335. • 6. Becskei A, Serrano L (2000) Nature 405:590–593. • 7. Becskei A, Seraphin B, Serrano L (2001) EMBO J 20:2528–2535. • 8. Kobayashi H, Kaern M, Araki M, Chung K, Gardner TS, Cantor CR, Collins JJ (2004) Proc Natl Acad Sci USA 101:8414–8419.

  22. Thank you

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