FAQ about AquaStool
1. How should I store the AquaStool solution?
AquaStool may be stored at 22 °C for 12 months. If AquaStool becomes precipitated when exposed to low temperature, you may incubate it at 37-50 °C for 15-20 min to resolubilize the reagent.
2. Why shouldn’t I use Bleach to disinfect AquaStool preserved fecal specimen?
AquaStool contains guanidine thiocyanate. It may react with Bleach (sodium hypochlorite) and release toxic gases.
3. How should I air-dry the mouse fecal samples?
Air-dried mouse fecal samples can be stored long term at room temperature for future genotype verification. To air-dry a mouse fecal pellet, incubate the fecal pellet in an opened microfuge tube on a dry heat bloc at 37 °C for 24 hours.
4. Why is my DNA/RNA solution showing a strong absorption below A260?
It is likely due to trace amount of guanidine salt contamination. If it interferes with your downstream applications, you may further purify the extracted DNA/RNA with a silica spin column (e.g., a plasmid miniprep column). Simply add an equal volume of 4 M GuHCl and 1M NaOAc (pH unadjusted, ~7.0) to your DNA/RNA solution (may contain the insoluble pellet) and load it into the spin column, centrifuge to allow DNA/RNA binding to the silica membrane, wash the column with 0.6 ml 75% EtOH, and elute the DNA/RNA in 50 μl of deionized water or TE buffer.
5. My mouse transgene was not amplified well, how may I improve it?
You may try the following to improve mouse fecal DNA amplification: (a) after freezing the fecal DNA solution at -20 °C, re-centrifuge it to pellet and remove any insoluble, which may contain PCR inhibitors; (b) reduce the amount of fecal DNA used per PCR reaction (i.e., try using 0.5, 0.25, 0.1 and 0.01 ml of extracted fecal DNA per PCR reaction); (c) increase PCR cycles to 65; (d) add 1 mM DTT and 0.1 mg/ml BSA to the PCR reaction; (e) use a gel imager to visualize faint amplicon bands; (f) use AquaRemove (#1208, order separately) with AquaStool to purify fecal DNA (see “Human fecal DNA/RNA extraction” for details); and (g) further purify the fecal DNA with a silica spin column as outlined in #4 Question and Answer above.