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Gel electrophoresis of nucleic acids is an analytical technique to separate DNA or RNA fragments by size and reactivity. Nucleic acid molecules are placed on a gel , where an electric field induces the nucleic acids (which are negatively charged due to their sugar- phosphate backbone) to migrate toward the positively charged anode .
Nucleic acid sequence-based amplification, commonly referred to as NASBA, is a method in molecular biology which is used to produce multiple copies of single stranded RNA. [1] NASBA is a two-step process that takes RNA and anneals specially designed primers, then utilizes an enzyme cocktail to amplify it.
For visualization purposes, the nucleic acid fragment is usually labelled with a radioactive, fluorescent or biotin label. Standard ethidium bromide staining is less sensitive than these methods and can lack the sensitivity to detect the nucleic acid if small amounts of nucleic acid or single-stranded nucleic acid(s) are used in these experiments.
When separating proteins or small nucleic acids (DNA, RNA, or oligonucleotides), the gel is usually composed of different concentrations of acrylamide and a cross-linker, producing different sized mesh networks of polyacrylamide. When separating larger nucleic acids (greater than a few hundred bases), the preferred matrix is purified agarose ...
Following rounds of template DNA extension from the bound primer, the resulting DNA fragments are heat denatured and separated by size using gel electrophoresis. In the original publication of 1977, [ 6 ] the formation of base-paired loops of ssDNA was a cause of serious difficulty in resolving bands at some locations.
The capture and capture-extender oligonucleotide bind to the target nucleic acid and immobilize it on a solid support. The label oligonucleotide and the branched DNA then detects the immobilized target nucleic acid. The immobilization of the target on a solid support makes extensive washing easier, which reduces false positive results.
Picture of an SDS-PAGE. The molecular markers (ladder) are in the left lane. Polyacrylamide gel electrophoresis (PAGE) is a technique widely used in biochemistry, forensic chemistry, genetics, molecular biology and biotechnology to separate biological macromolecules, usually proteins or nucleic acids, according to their electrophoretic mobility.
Rotavirus. A nucleic acid test (NAT) is a technique used to detect a particular nucleic acid sequence and thus usually to detect and identify a particular species or subspecies of organism, often a virus or bacterium that acts as a pathogen in blood, tissue, urine, etc. NATs differ from other tests in that they detect genetic materials (RNA or DNA) rather than antigens or antibodies.