Restriction digests of the clone give the following sizes (kb): ClaI--5.0; EcoRI--2.6, 2.3; SphI--3.3, 0.9, 0.8. One of three vectors (ATCC 87626 - 87628) containing antibiotic resistance gene cassettes, derived from the omega interposon. The cassettes can be used for insertional mutagenesis or for vector construction. Antibiotic concentration used for selection on standard media, e.g. Nutrient Agar for E. coli and R2YE for Streptomyces lividans is 30 ug/ml viomycin (Vm). After transformation of competent cells, 3 to 4 hours without selection were required for expression of the cassette, before the cells could be plated on selective medium. After transformation of comopetent cells, 3 to 4 hours without selection were required for expression of the cassette, before the cells could be plated on selective medium. It is sometimes easier to select transformed E. coli using another selection marker, and to subsequently select the ones having received omega-vph by replica plating on medium with viomycin. |
