Team:HZAU-China/Notebook
| Strain | Description | Usage | Sourse |
|---|---|---|---|
| E.coli trans-5α | Basic strain of calcium conversion | plasmid constructe, molecular cloning | Purchase by Shanghai Weidi Biotechnology |
| E.coli MG1655 | Type strain | This work | |
| S. typhimurium> SL1344 | Type strain | Phenotypic validation | Provide by Dr.Shan Li （Bio-Medical Center of HZAU | >
| S. typhimurium> SL1344(ΔsifA>） | Decrease toxicity and infectivity | Phenotypic validation | This work |
| S. typhimurium> SL1344(ΔsipD>） | knockout Type III secretion system | Phenotypic validation | This work | >
| Culture medium | Compositions |
| Luria Broth(LB) | 0.5% yeast extraction,1% NaCL and 1% tryptone(add 15 g/L agar when prepare solid culture) |
| Super Optimal Broth(SOB) | 0.5% yeast extraction, 0.05% NaCL and 2% tryptone(add 15 g/L agar when prepare solid culture) (add 5ml 2 mol/L MgCl2 before use.) |
Our fragments was PCR amplified with KOD(TOYOBO®) or PrimeSTAR(Takara®) according to product length.
Product is recycled with gel extraction kit from OMEGA® after electrophoresis.
ClonExpress® II One Step Cloning Kit (Vyzyme) was used to ligate every fragment to construct the most plasmids.
All plasmid constructs were confirmed by sequencing at Sangon®, Inc. (Wuhan,China).
A single frozen glycerol stock was used throughout this study for each bacterial strain.
1. Add 3-5μl plasmid to 50μl F-trans5α(Weidi Biotechnology)competent cells and incubate 5min in ice
, coated plates, select monoclonal colony PCR.Add extra 42℃ heat shock 45s and incubate 10min step will increase transformation efficiency.
Or 1.5kv, 4-5ms electroporate cell with 300-400 ng purified plasmid. Recover at 37°C 950rpm for 1h.
2.Plated on LB agar plates containing appropriate concentration of antibody for selection, grown overnight at 37°C. And prepare PCR reaction to select individual bacterial colony.
Cell are cultured overnight in LB broth containing corresponding antibiotics, and diluted to OD is 0.1 with fresh LB broth.
Expression was induced at early log phase by addition of different atc (40–140 ng/ml) concentrations. Culture the plate in 37℃ , 150 rpm. Every hour put it into a plate reader to measure its fluorescence/OD1.
1.Becskel, A. & Serrano, L. Engineering stability in gene networks by autoregulation. Nature 405, 590–593 (2000).
