Journal: PLoS ONE
Article Title: FabV/Triclosan Is an Antibiotic-Free and Cost-Effective Selection System for Efficient Maintenance of High and Medium -Copy Number Plasmids in Escherichia coli
Figure Lengend Snippet: Plasmid DNA yield. E . coli DH5α and JM109 were transformed with high-copy number pUC19-Bla, pUC19-FabV, pUC19-FabI, and medium-copy number pSA-Hp24-Bla, pSA-Hp24-FabV, pBR322-FabI plasmids and selected on LB agar plates containing 1μM Triclosan (for FabV/FabI plasmids) and or 100μg mL -1 ampicillin (for Bla plasmids). Seed cultures were used to inoculated 5mL LB broth in 50mL flasks and cultured for another 18 hours at 37 or 30°C while shaking at 250rpm. Cell density was then measured by absorbing the diluted samples at 600nm and normalized to 2 OD600. One mL of the normalized culture was then used to extract the plasmid following supplied protocol. The quantity of the extracted plasmid DNA was measured by fluorometry using Qubit Fluorometer and Qubit dsDNA BR Assay Kit (Invitrogen, life technology). Fig 4A shows plasmid DNA yield when bacteria were grown at 37°C, whereas Fig 4B shows the plasmid DNA yield from cultures incubated at 30°C. Error bars show standard deviations calculated from at-least six (6) independent experiments performed in triplicate.
Article Snippet: The quantity of the extracted plasmid DNA was measured by fluorometry using Qubit Fluorometer and Qubit dsDNA BR Assay Kit (Invitrogen, life technology).
Techniques: Plasmid Preparation, Transformation Assay, Cell Culture, Incubation