Storage Of Dna Extracts

Traditionally, purified DNA is stored in either sterile water or TE (10 mM Tris, pH 7.5-8.0, 1 mM EDTA). In either of these solutions, DNA may be stored for several months at either 4°C or — 20°C with little degradation. Extracted DNA stored in TE at temperatures between — 70°C and 37°C for 6 months demonstrated little degradation, whereas DNA stored at 45°C to 65°C shows signs of degradation within 24 hr and was completely degraded by 8 days.[37] Repeated freezing and thawing of DNA does not appear to result in degradation. For longer cryogenic storage, DNA should be stored in nuclease-free solutions at — 70°C (ultrafreezers) to — 196°C (liquid nitrogen).

Alternatively, DNA may be precipitated and stored in ethanol often layered with chloroform at room temperature or 4°C. Although lyophilized DNA stored at — 20°C is protected from degradation, problems with rehydration after prolonged storage have been reported.[37] Buffers containing EDTA have been used to store DNA at room temperature with little degradation for periods of time of less than a year[35,38] to over 2 years.[39] High concentrations of EDTA[38] and the addition of ethanol[35] have been found to further enhance DNA stability.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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