Intact Genomics (ig^®) XL1 Blue Max electrocompetent E. coli cells offer the highest transformation efficiencies of ≥5 x 10¹⁰ cfu/µg plasmid DNA which are ideal for applications requiring high transformation efficiencies, such as with cDNA or gDNA library construction. These cells have the capability to allow for the preparation of high quality plasmid DNA, single strand rescue of phagemid DNA and Blue/white screening.  XL1 Blue Max cells provide superb transformation efficiency, significantly higher than any competitors similar product, allowing for increased opportunity for experimental success.

Custom Aliquots Available

Specifications

Competent cell type:  ElectroCompetentSpecies:  E. coliFormat: TubesTransformation efficiency:  ≥ 2.5 x 10¹⁰ cfu/µg pUC19 DNABlue/white screening:  YesShipping condition:  Dry ice

Reagents Needed for One Reaction

ig^®  XL1 Blue Max electrocompetent cells:  25 µlDNA (or pUC19 Control, 10 pg/µl):  1 µlRecovery medium:  1 ml

Storage

ig^® XL1 Blue Max electroCompetent cells:  -80 ºCpUC19 control DNA:  -20 ºCRecovery medium:  4 ºC

Genomic Featuresig^®  XL1 Blue Max electrocompetent cells have the following features:

• XL1 Blue Max cells are tetracycline resistant.
• XL1 Blue Max cells are endonuclease (endA) deficient, which greatly improves the quality of miniprep DNA.
• XL1 Blue Max cells recombination (recA) deficient, improving insert stability.
• Cleavage of cloned DNA by the EcoK endonuclease system is prevented by the hsdR mutation.
• Bue-white color screening via the lacIq Z∆M15 gene on the F´ episome.

Genotype

recA1 endA1 gyrA96 thi-1 hsdR17 supE44 relA1 lac [F´ proAB lacIq Z∆M15 Tn10 (Tetr )]

Quality Control

Transformation efficiency is tested by using the pUC19 control DNA supplied with the kit and using the protocol given below. Transformation efficiency should be ≥5 x 10¹⁰ CFU/µg pUC19 DNA. Untransformed cells are tested for appropriate antibiotic sensitivity. 

General Guidelines

Follow these guidelines when using ig^® XL1 Blue Max ElectroCompetent Cells:

• Handle competent cells gently as they are highly sensitive to changes in temperature or mechanical lysis caused by pipetting.
• Thaw competent cells on ice, and transform cells immediately following thawing. After adding DNA, mix by tapping the tube gently. Do not mix cells by pipetting or vortexing.

Note: A high-voltage electroporation apparatus such as Bio-Rad Gene Pulser II #165-2105, capable of generating field strengths of 16 kV/cm is required.

Example Calculation of Transformation EfficiencyTransformation Efficiency (TE) is defined as the number of colony forming units (cfu) produced by transforming 1µg of plasmid into a given volume of competent cells.

TE = Colonies/µg/Dilution

Transform 1 µl of (10 pg/µl) pUC19 control plasmid into 50 µl of cells, add 950 µl of Recovery Medium. Dilute 10 µl of this in 990 µl of Recovery Medium and plate 50 µl. Count the colonies on the plate the next day. If you count 100 colonies, the TE is calculated as follows:

Colonies = 100µg of DNA = 0.00001Dilution = 50/1000 x 10/1000 = 0.0005TE = 100/.00001/.0005 = 2.0×10¹⁰1217-12 1217-24