DH5α λpir, S17-1 λpir, SM10 λpir, DH5a (pRK2013), DH5a (pRK2073), REG-1, REG-12, REG-811菌株感受态细胞-R6K ori复制子质粒扩增

E. coli DH5α λpir strain
E. coli DH5α λpir strain contains the pir gene (lysogenized lpir phage lysogen) and is designed for cloning and propagation of plasmids with R6K origin of replication sequence (like pUTmini-Tn5 vectors). To transfer this plasmids directly from DH5α λpir donor strain to the recipient strain it is necessary to perform a triparental mating with a helper strain such as E. coli DH5α (pRK2013) (see Helper E. coli strains). The genotype of the strain is sup E44, ΔlacU169 (ΦlacZΔM15), recA1, endA1, hsdR17, thi-1, gyrA96, relA1, λpir phage lysogen.

E. coli S17-1 λpir strain
E. coli S17-1 λpir strain contains the pir gene (λpir). This strain have chromosomally integrated conjugal transfer functions (RP4 transfer functions), so when it is used as specific host strain into which the transposon vector DNA is transformed, the transfer occurs by biparental mating (a helper strain is not necessary). The genotype of the strain is TpR SmR recA, thi, pro, hsdR-M+RP4: 2-Tc:Mu: Km Tn7 λpir.

E. coli SM10 λpir strain
E. coli SM10 λpir strain contains the pir gene (lysogenized with λpir phage) and it is designed for cloning and propagation of plasmids with R6K origin of replication sequence (such as pUT mini-Tn5 vectors). The plasmids containing the R6K origin of replication require the R6K-spicific replication protein lpir gene for propagation. The genotype of the strain is KmR, thi-1, thr, leu, tonA, lacY, supE, recA::RP4-2-Tc::Mu, pir.

E. coli DH5a (pRK2013) strain
E. coli DH5a (pRK2013) strain contains the helper plasmid pRK2013, which provides tra and mob genes required to transfer the DNA cloned in pUTmini-Tn5 plasmids into the recipient strain, from donor strains, lacking these genes.  The genotype of the strain is supE44, ΔlacU169(ΦlacZΔM15), recA1, endA1, hsdR17, thi-1, gyrA96, relA1, pRK2013 (KmR oriColE1 RK2-Mob+ RK2-Tra+).

E. coli DH5a (pRK2073) strain
E. coli DH5a (pRK2073) strain contains the helper plasmid pRK2073, that provides tra and mob genes required to transfer the DNA cloned in pUTmini-Tn5 plasmids into the recipient strain, from donor strains lacking these genes. The genotype of the strain is supE44, ΔlacU169(Φ80lacZΔM15), recA1, endA1, hsdR17, thi-1, gyrA96, relA1, pRK2073 (StR oriColE1 RK2-Mob+ RK2-Tra+).

E. coli REG-1 strain
E. coli REG-1 strain contains nahR/Psal::xylS regulator element integrated into the chromosome, and works like host of CASCADE™ system. The strain genotipe is Mini-Tn5 (kanR nahR/Psal::xylS) mcrA Δ(mrr-hsdRMS-mcrBC) F80lacZ ΔM15 ΔlacX74 recA1 araD139 (ara-leu)7697 galU galK rpsL endA1 nupG. The strain is supplied as a stab culture shipped at room temperature, and can be stored at 4°C for a few days.

E. coli REG-12 strain
E. coli REG-12 strain is a mutant of E. coli k12 with riphampicine resistance (RifR) that contains nahR/Psal::xylS regulator element integrated into the chromosome (Royo et. al. 2005). The strains are fast-growth E. coli that can contains CASCADE™ expression vectors (Cebolla et al. 2001). E. coli REG-12 can reach high celular density if it is cultivated in a rich medium and can grow in a minimum medium with amonia and glucose-like sources of nitrogen and carbon, respectively. The strain genotype is F+ mini-Tn5 (KanR nahR/Psal::xylS) RifR. The strain is provided as a stab culture at room temperature. For greater longevity, store at 4ªC.

E. coli REG-811 strain
REG-811 is a rifampicin, kanamycin-resistant (Rif Kan) derivative of the E. coli B strain BL21 (Studier and Moffatt, 1986) that contains the nahR/Psal::xylS regulatory element (Cebolla et al., 2001) integrated in the chromosome. REG-811 can be used as a host strain for recombinant protein expression with CASCADE™ vectors; it grows in rich or mineral media and can be cultured under high cell density conditions.

Some strains are available in the format of competent cells:

• E. coli DH5α λpir competent cells set

• E. coli DH5α competent cells set

• E. coli REG-811 competent cells set