Protocol reproducibly generates competent cultures of E. coli that yield 1 x 108 to 3 x 108 transformed colonies/µg of plasmid DNA. The protocol works optimally when the bacterial culture is grown at 18°C. If a suitable incubator is not available, a standard bacterial shaker can be set up in a 4°C cold room and regulated to 18°C. - [Read Preparation and Transformation of Competent E. Coli: "Ultra-Competent" Cells Protocol]
Protocol reproducibly generates competent cultures of E. coli that yield 1 x 108 to 3 x 108 transformed colonies/µg of plasmid DNA. The protocol works optimally when the bacterial culture is grown at 18°C. If a suitable incubator is not available, a standard bacterial shaker can be set up in a 4°C cold room and regulated to 18°C. - [Read Preparation and Transformation of Competent E. Coli: "Ultra-Competent" Cells Protocol]
Protocol for the preparation of a prepacked IMAC column. Purification of histidine-tagged proteins on a milligram scale can be performed conveniently on a small (1to 5-ml) immobilized metal-ion chromatography (IMAC) column using a syringe to load the sample, wash the column, and elute the protein. - [Read Preparation of a Prepacked IMAC Column Protocol]
Triazine dyes, such as Cibacron Blue 3GA, can be linked to a hexyl spacer arm and then immobilized on a polyhydroxyl support matrix that has been activated with either 1,1-carbonyldiimidazole or epichlorohydrin. An alternative procedure for immobilizing dyes using the direct coupling method is provided in Immobilization of Dyes on Polyhydroxyl Matrices Using the Direct Coupling Method. - [Read Preparation of Affinity-Ligand Resins by Immobilization of Dyes on Polyhydroxyl Matrices]
Protocol for the preparation of ion-exchange chromatography column. Ion-exchange chromatography (IEC) can be used as a crude step in a protein purification scheme, or, with proper preparation, as a high-resolution step. If high resolution is desired, considerable care should be taken during column preparation, choice of IEC media, and column packing. - [Read Preparation of an Ion-Exchange Column Protocol]
It is desirable to prepare subcellular fractions, either to localize proteins or to improve the sensitivity of protein detection. This procedure describes the enrichment of chloroplasts from Arabidopsis. - [Read Preparation of Arabidopsis Chloroplasts Protocol]
It is often desirable to prepare subcellular fractions, either to localize proteins or to improve the sensitivity of protein detection. This procedure describes the enrichment of mitochondria from Arabidopsis. - [Read Preparation of Arabidopsis Mitochondria Protocol]
This protocol provides a sufficient sample for several determinations of cAMP using the acetylation protocol. The method chosen for measuring the content of cyclic adenosine 3',5'-monophosphate (cyclic AMP or cAMP) in splenic B lymphocytes (B cells) is an enzyme linked immunoassay system. Protocol includes information on: Treatment of Cells and Preparation of Extracts; Reagents and Materials. - [Read Preparation of B-Lymphocyte Lysates for Cyclic AMP Determination]
Many replacement vectors (e.g., the EMBL series, {lambda}2001, and {lambda}DASH) contain a series of restriction sites, arranged in opposite orientations, at each end of the central stuffer fragment. Digestion of these vectors with two different restriction enzymes yields left and right arms, a stuffer fragment, and short segments of the polycloning sites. These can easily be removed from the arms by differential precipitation with isopropanol or spun-column chromatography. - [Read Preparation of Bacteriophage lambda DNA Cleaved with Two Restriction Enzymes Protocol]
Protocol for preparation of denaturing polyacrylamide gels containing formamide.The inclusion of formamide in sequencing gels eliminates secondary structure in the DNA during electrophoresis. Formamide gels are particularly useful and almost a necessity when sequencing DNA templates with a G/C content >55%. - [Read Preparation of Denaturing Polyacrylamide Gels Containing Formamide Protocol]
This protocol describes the preparation of concatamerized oligonucleotides and their coupling to cyanogen-bromide-activated Sepharose. The procedure uses a commercially activated resin, which can be purchased as a lyophilized powder. Keith Brocklehurst et al. - [Read Preparation of DNA Affinity Resin - Subscription Required]
Protocol for preparation of DNA for pulsed-field gel electrophoresis: isolation of DNA from mammalian cells and tissues. Genomic DNAs from mammalian cells are prepared for pulsed-field gel electrophoresis by lysing cells in situ in an agarose plug. Following digestion with an appropriate restriction enzyme, the plug is loaded directly into the well of a pulsed-field gel or it can be melted before loading. - [Read Preparation of DNA for Pulsed-field Gel Electrophoresis: Isolation of DNA from Mammalian Cells]
Protocol for preparation of DNA for pulsed-field gel electrophoresis: isolation of intact DNA from yeast. Yeast cells are first treated enzymatically to break down the cell walls and then resuspended in low-melting-temperature agarose plugs. The DNA is liberated by infusing the plugs with lysis buffer and proteases. This method is used to prepare both conventional and artificial yeast chromosomes. - [Read Preparation of DNA for Pulsed-field Gel Electrophoresis: Isolation of Intact DNA from Yeast]
Protocol for the preparation of electrolyte gradient gels. Electrolyte gradients are formed when buffers of different concentrations are used in the upper (low electrolyte concentration) and lower (high electrolyte concentration) chambers of the electrophoresis device. - [Read Preparation of Electrolyte Gradient Gels Protocol]
Method is used chiefly to genotype transgenic and knockout mice. Each 6-10-mm snippet of mouse tail yields 50-100 µg of DNA that can be used in dot or slot blotting to detect a transgene of interest, in Southern hybridization to detect DNA fragments that are <20 kb in size, and as a template in PCRs. - [Read Preparation of Genomic DNA from Mouse Tails and Other Small Samples Protocol]
In Vitro Translated Xenopus Mos Kinase Assay Protocol. In response to progesterone, immature Xenopus oocytes mature to eggs that can be fertilized. The Mos protein kinase is essential for oocyte maturation, most likely due to its ability to activate the MAP kinase cascade. This MAP kinase cascade eventually leads to the activation of Cdc2/cyclin B and entry into M phase. In this protocol, tagged Mos kinase is translated in vitro, immunopurified, and used in a kinase assay.