StellarTM Competent Cells

Description

Stellar Competent Cells are anE. coliHST08 strain that provides high transformation efficiency. These cells can be used in a wide variety of applications-from preparation of cDNA and genomic libraries, to construction of longer-length genomic libraries, to subcloning, and even methylated DNA cloning. Stellar Competent Cells lack the gene cluster for cutting foreign methylated DNA mrr-hsdRMS-mcrBCandmcrA , and are therefore useful for cloning methylated DNA. The cells can also be used for blue/white screening i.e., alpha-complementation when transformed with vectors containing thelacZalphagene. This package includes 50 tubes of competent cells 100 mul/tube , SOC Medium and a pUC19 vector. Our products are to be used forResearch Use Only. They may not be used for any other purpose, including, but not limited to, use in humans, therapeutic or diagnostic use, or commercial use of any kind. Our products may not be transferred to third parties, resold, modified for resale, or used to manufacture commercial products or to provide a service to third parties without our prior written approval. Back The high efficiency of Stellar Competent Cells was especially noticeable in the transformation of 10 kb and 20 kb plasmids.Using DNA plasmids of 2 kb 100 pg , 10 kb 1 ng , and 20 kb 1 ng , each strain of competent cells was transformed and plated on ampicillin-containing LB agar plates. Transformation efficiencies were determined based on the colony counts obtained. Back The difference in transformation efficiencies of the competent cells was particularly prominent when cloning 20 kb fragments.Ligation reactions were set up with either 100 ng of a 2 kb, Hind III-cut DNA fragment + 50 ng of Hind III/BAP-cut pUC118 vector, or 75 ng of a 20 kb, Hind III-cut DNA fragment + 25 ng of Hind III/BAP-cut pUC118 vector. All reactions were performed at 16C for 6 hours using the Takara DNA Ligation Kit Cat# 6023 or 6024 . Each strain of competent cells was transformed using portions of these reaction mixtures and plated on ampicillin-containing LB agar + X-gal . Transformation efficiencies were determined based on the white colony counts obtained. Back Stellar colonies transformed with larger plasmid clearly showed a faster growth rate.DNA plasmids of 2 kb Panel A and 10 kb Panel B were each used to transform Stellar and DH10B competent cells with similar genetic characteristics, including methylation requiring restriction. This experiment used the same method as in Figure 1. Photographs of colonies on agar were taken after 15 hours of incubation. Back