This is a dual-purpose strain that combines theΔlpp structural modification with Red Fluorescent Protein. It allows researchers to track a "leaky" or "surface-display" strain in real-time using fluorescence.
For Research Use Only. Not intended for use in food manufacturing or medical procedures (diagnostics or therapeutics). Do Not Use in Humans.
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Product Information
Product Overview
This is a dual-purpose strain that combines theΔlpp structural modification with Red Fluorescent Protein. It allows researchers to track a "leaky" or "surface-display" strain in real-time using fluorescence.
Target
Escherichia coli Nissle 1917
Applications
Used to study how structural mutations affect the localization and survival of EcN in the gut. The advantage is the ability to visually confirm the presence of the engineered strain while simultaneously benefiting from its altered membrane properties.
Product Identity & Gene Details
Chassis Strain
Escherichia coli Nissle 1917
Target Gene(s)
lpp, A5 and RFP
Gene Function
Δlpp: Deletion of Braun's lipoprotein to increase membrane permeability and release periplasmic space.
A5: A specific protein scaffold or "linker" used to tether heterologous proteins to the outer membrane.
RFP (Red Fluorescent Protein): A structural protein that glows red under a fluorescent microscope. It is used to visualize the bacteria in tissue samples or in vitro.
Modification Type
Combined knockout and fluorescent labeling.
Genetic Architecture
Promoter System
Constitutive or Inducible
Selection Marker
Standard Antibiotic Marker or Markerless/Scarless (No resistance genes)
Delivery & Service Standards
Deliverables
Glycerol Stocks
Shipping Conditions
Dry Ice Shipping
Lead Time
4-8 weeks
Documents
Certificate of Analysis (COA) or Project Report
Verification
PCR Sequencing
Engineered Strain Recovery & Handling
Immediate Post-Delivery Steps
1. Transfer to Storage: Immediately transfer the cryovials to a -80°C ultra-low temperature freezer. 2. Avoid Fluctuations: Do not store the vials in a "frost-free" freezer, as the temperature cycles can damage the cell membranes of the engineered strains.
Strain Recovery Protocol
To ensure maximum viability, follow this standard recovery procedure: 1. Preparation: Prepare the appropriate selective agar medium (e.g., LB agar + specific antibiotic as listed in the COA). 2. Partial Thawing (The "Scratch" Method): * Place the cryovial on dry ice. Do not thaw the entire vial. Use a sterile inoculation loop or pipette tip to "scratch" a small amount of ice from the surface of the frozen stock. 3. Streaking: Streak the cells onto the selective agar plate to obtain single colonies. 4. Incubation: Invert the plate and incubate at the specified temperature (e.g., 37°C for E. coli or 30°C for S. cerevisiae) for 16-24 hours. 5. Subculturing: Pick a single, well-isolated colony to inoculate into liquid media for your experiments.
Usage Precautions & Best Practices
Antibiotic Pressure
1. Maintenance: For strains containing plasmids or specific resistance markers, always use the correct concentration of antibiotics in both solid and liquid media to prevent plasmid loss or contamination.
2. Markerless Strains: If the strain is a "scarless" integrated knockout, antibiotic pressure is not required for maintenance, but periodic genotypic verification is recommended.
Induction Conditions
1. If your strain uses an inducible promoter (e.g., T7/IPTG or Arabinose), ensure the culture reaches the optimal OD600 (typically 0.6-0.8) before adding the inducer. 2. Verify the optimal induction temperature, as engineered strains often produce better results at lower temperatures (e.g., 16-25°C) to prevent inclusion body formation.
Disposal
All waste (vials, tips, plates) must be autoclaved at 121°C for at least 20 minutes or chemically disinfected before disposal.
