This method relies on phase separation by centrifugation of a mix of the aqueous sample and a solution containing phenol and chloroform, resulting in an upper aqueous phase and a lower organic phase (mainly chloroform). DNA is present in the aqueous phase and can be recovered by precipitation with isopropanol or ethanol.
Human umbilical vein endothelial cells (HUVEC) are commonly used as a laboratory model system for the physiological and pharmacological investigations. This video describes how to derive HUVEC from the endothelium of veins of the umbilical cord.
DNA sequencing is a technique to determine the order of the nucleotide bases-adenine, guanine, cytosine, and thymine. It is indispensable for basic biological research and discovery.
Dialysis (ultrafiltration) is a method to concentrate protein or other macromolecules through a membrane with defined pores. The membranes will have a molecular weight cut-off (MWCO). This is the limit of size (or range) of a protein that can fit through the membrane.
Down syndrome, also known as trisomy 21, is a genetic disorder caused by the somatic aneuploidy of chromosome 21. It is typically associated with delayed physical growth, characteristic facial appearance, and mild to moderate intellectual disability. Down syndrome is the most common somatic aneuploidy in humans occurs in 1 out of 700 live births in all ethnic groups. Here we present a brief introduction to the common knowledge of Down syndrome.
Dot blot is a technique can be used as a semiqualitative method for rapid screening of a large number of samples. It is for detecting, analyzing, and identifying proteins, similar to the western blot technique but differing in that protein samples are not separated electrophoretically but are spotted through circular templates directly onto the membrane.
Diethylpyrocarbonate (DEPC) is used in the laboratory to inactivate the RNase enzymes from water and other laboratory utensils. It inactivates the RNases by the covalent modifications of the histidine residues. DEPC treated (and therefore RNase-free) water is used in handling of RNA to reduce the risk of RNA being degraded by RNases.
DNA electrophoresis is an analytical technique used to separate DNA fragments based on size, electrical charge and other physical properties. The DNA separates out into bands, with the distance from the electrode corresponding to length of the strand. The technique plays a role in identifying genes for diagnosing disease and for other forms of genetic research.
It s very important to test cell lines and cell culture media to determine if microbial contamination is present. The culture media used for the tests are tryptic soy broth (TSB) for the detection of aerobic and anaerobic bacteria, and fluid thioglycollate medium (FTM) for the detection of erobes, facultative anaerobes and fungi.
Agarose gel electrophoresis is a method used to separate a mixed population of DNA or RNA fragments by length. This video shows you how to prepare the agarose gel.
DNA extraction is a routine procedure to collect DNA for subsequent molecular analysis. This video shows you how to extract DNA from mouse tails. There are three basic steps: (i) break cells by lysis buffer, (ii) digest protein and remove contamination by proteinase, (iii) precipitating the DNA.