Southern blot technique

The northern blotting technique is similar to the Southern blotting technique with the exception that northern blots detect specific sequences of RNA, not DNA. 

Southern blotting Technique used to identify and locate DNA sequences which are complementary to another piece of DNA called probe using electrophorectic gels for separation of DNA and membrane filters with radiolabelled complementary probes. 

Transfer by blotting to a nylon membrane allows the heat treatment involved in hybridisation to take place. Southern blotting technique. 

Figure 3.24 Restriction fragments from digestion of two samples of DNA. These are produced as a result of the activity of restriction enzymes on the samples of DNA and separation of the fragments by the Southern blotting technique (Appendix 3.12). Numbers refer to the length of the fragments, (i.e. number of nucleotides).

One way to select a desired segment of DNA from a digest of chromosomal DNA is to sort out the "restriction fragments" by gel electrophoresis.613 The DNA from the gel can be transferred to a nitrocellulose sheet while retaining the separation pattern using a method devised by Southern.560 614 615 In this Southern blot technique, solvent flows from a pool beneath the gel up through the gel and the nitrocellulose sheet into paper towels. The DNA is trapped on the nitrocellulose in the same pattern observed in the electrophero-gram. A suitably labeled probe such as cDNA with... 

Due to the small volumes and feature sizes, reaction rates are found to be quite different in the microbiosensor system in comparison to their macro counter part. Most of this is due to the fact that diffusion is not the limiting factor in a reaction any longer. For example, the diffusion time of a particle with a diffusion coefficient = 10 m s is 15 min to travel a distance of 1 mm, but only 10 s to travel 100 /rm and only 0.1 s to travel 10/rm [37]. Therefore, DNA hybridization reactions, antibody-antigen binding events, and enzyme—substrate catalytic reactions take place in a fraction of the time required earlier. DNA hybridization can be accomplished in a matter of seconds in a microchannel system, while it takes in the order of an hour when employing standard Northern or Southern Blotting techniques with a piece of nylon membrane soaking in several milliliters of hybridization solution. 

Biotechnology is being used in the diagnosis of disease. For example, samples of DNA are treated with restriction endonucleases and then subjected to electrophoresis on gels. Using the Southern blot technique, the x restriction fragments on the gel are hybridized with radioactive cDNA... 

Northern blot technique A technique that is used to identify RNA. RNA is separated according to size by use of a denaturing gel and electrophoresis prior to being blotted onto a solid support. The mRNA transcripts are then detected by hybridization with a radioactive labelled probe. The abundance of the mRNA is indicated by the intensity of the radioactive signal. See also Southern blot technique. NOS nitric oxide synthase, nosocomial synonomous with HAL NO synthase See nitric oxide synthase. 

Southern blot technique A very sensitive experimental technique used to detect the presence of DNA sequences, amongst restriction fragments, that are complementary to a radiolabelled DNA or RNA probe. DNA is separated by electrophoresis on a gel, transferred to membrane niters and then labelled probes are applied to locate complementary DNA sequences. See Northern blot technique, spacer DNA DNA that separates one gene from another, spare receptors See receptor reserve, spasm An involuntary strong contraction of a muscle. In the skeletal muscle of the body the cause may he of local... 

Cellular DNA is extracted, resuspended, restriction enzyme digested, and elec-trophoresed in a 1% agarose gel, and transferred via Southern blot technique to nitrocellulose membranes. The nitrocellulose is baked, prehybridized, hybridized, washed, quantitatively analyzed for radioactivity, and exposed to film. 

A EXPERIMENTAL FIGURE 9-26 Southern blot technique can detect a specific DNA fragment in a complex mixture of restriction fragments. The diagram depicts three different restriction fragments in the gel, but the procedure can be applied to a mixture of millions of DNA fragments. Only fragments that... 

The principle behind DNA chips was bom from the basic Southern blot technique, and it is now a fast-moving field at the cutting edge of genome research. The two main scientific elements of DNA chips are the manufacture of microarrays with single-stranded oligonucleotides attached to pixels on the surface and hybridization analysis with spatial resolution. 

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