Материал из Zbio
[править] DNA storage
- normal storage: -20°C
- very long (>200kb) DNA should not be freezed. Store it at +4°C. NB! microbial degradation may happens at this temperature
- salt/ethanol precipitate is a safe way of transportation at ambient temperature
- DNA is chemically unstable in acidic solutions
[править] Contamination-dangerous DNA
- "PCR-safe" and "sterile" work significantly differ from each other.
- Use reasonable aliquotes of reagents. If contamination happens, through them away.
- Amplification with dUTP and UDGase digestion does not prevent contamination completely. It decrease contamination level on ~3 orders of magnitude.
- Try to organize a day work from "clean" to "dirty".
- Use separate pen, markers, etc. in dirty area. Do not use laboratory journal in dirty area.
- Remove or clean contamination-dangerous things as early as possible:
- wash electrophoresis chambers and plates;
- clean bench immediately after dirty work (gel-band cutting, ePCR transfer, etc.);
- wash hands and gloves.
- Spin down (for at least 5 sec) all contamination-dangerous tubes before opening.
- Do not touch anything by contaminated gloves/hands:
- water source;
- door handles.
[править] How to remove DNA?
Bad choice: 100% or 70% ethanol. Because DNA does not solubilize in it.
- whater, may be with detergents. DNA is easily disolvable in this buffer.
- NH3-containing cleaning solution. After washing by such solution surfaces strongly (irreversibly) adsorb DNA.
- hypochlorit Na, several minutes. Chemical degradation of DNA.