An oligodeoxynucleotide primer hybridized to mRNA is extended by an RNA-dependent DNA polymerase to create a cDNA copy that can be amplified by PCR. Depending on the purpose of the experiment, the primer for first-strand cDNA synthesis can be specifically designed to hybridize to a particular target gene, or a general primer such as oligo(dT) can be used to prime cDNA synthesis from essentially all mammalian mRNAs - [Read Amplification of cDNA Generated by Reverse Transcription of mRNA Protocol]
This stage achieves four goals: polishing the ends of double-stranded DNA, ligation of synthetic linkers or adaptors, digestion of the attached linkers to create cohesive termini, and preparing the cDNA for cloning. - [Read Attachment of Linkers or Adaptors for Construction of cDNA Libraries]
Techniques on how to create gradients of iodixanol for the fractionation of mammalian cells. These gradients can be generated as pre-formed discontinuous or continuous gradients. These gradients are invariably run in swinging-bucket rotors in low-speed centrifuges. - [Read C2 Preparation of pre-formed iodixanol gradients for mammalian cells.]
When imaging specimens in the optical microscope, differences in intensity and/or color create image contrast, which allows individual features and details of the specimen to become visible. Contrast is defined as the difference in light intensity between the image and the adjacent background relative to the overall background intensity. In general, a minimum contrast value of 0.02 (2 percent) is needed by the human eye to distinguish differences between the image and its background. - [Read Contrast in Optical Microscopy]
DNA Ligation- http://www.bio.com/protocolstools/protocol.jhtml?id=p2053
Description and protocol of the steps required to join together plasmid and insert fragments to create a new plasmid. Paul Kaufman, Univ California. - [Read DNA Ligation]
Shotgun sequencing of a large segment of DNA involves random fragmentation of the target region into smaller segments that are subsequently cloned into a bacteriophage M13 vector. The goal is to create a library of overlapping clones that provide at least fivefold coverage over the entire length of the target fragment. - [Read Generation of a Library of Randomly Overlapping DNA Inserts Protocol]
Protocol for precision engineering of plant gene loci by homologous recombination cloning in Escherichia coli. Describe the basis for homologous recombination cloning in E. coli, the available tools and resources, together with a protocol for long range cloning and manipulation of an Arabidopsis thaliana gene locus, to create constructs co-ordinately driven by locus-specific regulatory elements. - [Read Precision Engineering of Plant Gene Loci by Homologous Recombination Cloning in E coli Protocol]
This protocol describes a discontinuous gradient, which resolves the mitochondria from both lighter and denser organelles. Because the centrifugation is carried out for 4 h, diffusion will create a partially continuous gradient and this probably contributes to the resolution of the mitochondria from the lighter lysosomes. - [Read Purification of Mammalian Liver Mitochondria by Flotation Through a Pre-formed Discontinuous Iodixan]
The DNA Ligation protocol described here contains the steps required to join together using ligase enzyme both plasmid DNA and insert DNA fragments in order to create a new plasmid. This new ligated plasmid can be transformed after into competent bacteria to produce DNA for mini, midi or maxi-prep isolation.