The proprietary SE1 bacterial strain is recommended for protein expression when using StabyExpress, CherryExpress, StabyCodon or CherryCodon kits. This strain was derived from E. coli BL21(DE3) strain. SE1 is an expression strain allowing for the use of the T7 expression system. The gene encoding the T7 RNA polymerase is inserted into the chromosome of the expression bacteria. The protein expression is repressed by lacI and induced by the addition of IPTG into the culture medium or using an auto-inducible medium as StabyTMSwitch. Additionaly, the SE1 bacteria contain the ccdB selection gene in its chromosome allowing for the perfect plasmid stabilization (even without antibiotics) and consequently higher yields of expressed proteins.Genotype: F-, CmR, ompT, hsdSB (restriction-, modification-), gal, dcm, DE3 (lacI, T7polymerase under control of the PlacUV5 promotor), ccdB+Bacteria are shipped (on dry ice) with SOC medium. Contains 20 x 100 μl chemically-competent SE1 bacteria for expression.