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My N.U. P.A.L. N orthwestern U niversity’s P seudomonas a eruginosa L ocator. 1.7 million. Hospital acquired Infections. 170,000. Pseudomonas aeruginosa Infections. Quorum Sensing. R. R. R. Target Gene . Autoinducer gene. Expression. Bacterium.
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My N.U. P.A.L. Northwestern University’s Pseudomonas aeruginosa Locator
1.7 million Hospital acquired Infections 170,000 Pseudomonas aeruginosa Infections
Quorum Sensing R R R Target Gene Autoinducer gene Expression Bacterium
Quorum Sensing in Pseudomonas aeruginosa PAI-2 PAI-1 LasR LasR LasR LasR LasR RhlP LasP Las sequence Rhl sequence RhlR RhlR RhlR RhlR RhlR RhlR
Project Goal Biosensor Reliable Fast Simple & Inexpensive
Autoinducer Pseudomonas aeruginosa R R R R R Induced Promoter R-protein synthase RBS RBS GFP synthase Constitutive Promoter E. Coli Biosensor
GFP lasR Finding the Parts rhlP lasP RBS rhlR
Parts Submitted 38 parts Designed and Constructed 21 parts Function Validated 19 parts Characterized
Parts Characterized 6 parts Rhl promoter Constructs 5 parts Las Promoter Constructs 4 parts Newly Isolated Promoter Constucts 4 parts Previously Existing Registry Parts
Favorite Parts LasR, PAI-1 BBa_K575024 RhlR, PAI-2 BBa_K575033 RhlR, PAI-2 Newly isolated BBa_K575046
Testing Methods • Overnights • Sample Preparation • Plate Reader
Las Based Detection System L L BBa_K575024 LasR/PAI-1 Induced Promoter RBS GFP Constitutive Promoter RBS LasR
Time Response of LasR/PAI-1 Biosensor No discrimination between different concentrations Autoinducer added No Autoinducer
LasR/PAI-1 Biosensor Exhibits Binary Sensing Flat transfer function Steady State Fluorescence per OD Steady State Fluorescence of the construct does not change in response to varying PAI-1 dosages Autoinducer Concentrations (μM)
Rhl Based Detection System R R BBa_K575033 RhlR/PAI-2 Induced Promoter RBS GFP Constitutive Promoter RBS RhlR
Time Response of RhlR/PAI-2 Biosensor Increasing autoinducer concentration Discriminates between different concentrations Autoinducer added No Autoinducer
RhlR/PAI-2 Biosensor Exhibits Dose-Dependent Response Y=68.234ln(x) + 142.89 R2=0.9322 Steady State Fluorescence per OD Autoinducer Concentrations (μM)
Rhl Based Detection System R R BBa_K575046 (Isolated from Genome) RhlR/PAI-2 Induced Promoter RBS GFP Constitutive Promoter RBS RhlR
Time Response of RhlR/PAI-2 Biosensor Isolated from the Genome Increasing autoinducer concentration Discriminates between different concentrations Autoinducer added No Autoinducer
RhlR/PAI-2 Biosensor Isolated from the Genome Exhibits Dose-Dependent Response Y=33.43ln(x) + 72.293 R2=0.9694 Steady State Fluorescence per OD Exhibited superior discrimination between varying PAI-2 dosages Autoinducer Concentrations (μM)
Purpose Better understand why the biosensors behave differently in the context of the applications Optimize parameters and achieve the set goal Develop and apply a model to other pathogen sensing constructs or devices
12 11 10 Ae Ai 3 5 mRNA M CP R D 4 Directly translated each rate to ODEs 2 1 IP 8 13 6 7 System of non-linear equations 9 mRNA GFP
Analysis Sensitivity Identify Critical Parameters Simulation
Qualitative Mathematical Fit to the LasR Biosensor Data 1μM-100μM 0.5μM Arbitrary Concentration of GFP 0.1μM Data No Autoinducer Simulated Time (min)
Qualitative Mathematical Fit to the RhlR Biosensor Data 100μM 50μM 0.5μM 0.1μM 20μM 10μM 5μM Arbitrary Concentration for GFP Data No Autoinducer Simulated Time (min)
10 Critical Parameters Ai 11 LasR/PAI-1 12 3 Ae 5 ↓RhlR/PAI-2 M R D mRNA 4 CP 2 1 ↑LasR/PAI-1 RhlR/PAI-2 IP 8 RhlR/PAI-2 , IP +ve co-operativity 13 6 7 9 mRNA GFP
Implications Identified system parameters which fluctuated the biosensors’ response Can potentially optimize constructs to “tune” the sensitivity Generalized model which mathematically represents autoinducer detection
Application Proposed Biosensor Schematic Well Photodiode Blue LED Orange filter
Application Swab is inserted into a vial with the biosensor Swab Biosensor fluoresces in the presence of the pathogen
Biowarfare Tear gas Artificial Life Unknown consequences
Dr. Dale Mortensen Nobel laureate in Economics Dr. Keith Tyo Synthetic biologist Human Practices Dr. Laurie Zoloth Bioethicist We promise not only to do the cool research, but to stand by every mistake and every error from now until the future, just like you would stand by profit taking. -Dr. Laurie Zoloth
Results Summary 19 parts characterized The Las based biosensor exhibited a binary response The Rhl based biosensor exhibited a dose dependent response High discrimination between varying autoinducer dosages exhibited by the newly isolated promoter
Initial Goals Fast Simple and Inexpensive Reliable
Future Prospects Future iGEM Projects Clinical Application
THANK YOU. Questions?