I had done DNA extraction by using QIAmp DNA mini extraction kit (referring tissue protocol) to extract DNA from my adult helminth samples. But I failed twice. The samples were preserved in 70% alcohol before the DNA extraction is done. I had follow the protocol and incubate the grinded samples with lysis buffer and proteinase K overnight. Any idea what mistake I had done?
Hello Debbra,
How do you grind your samples? And do you remove the Ethanol before that step? I'm not entirely sure on the contents of the lysis buffer, but it might be, that the alcohol possibly interferes with the buffers and/or the binding of your DNA to the membranes (in the later steps), which could be solved by washing your samples before you grind and lyse them.
Best regards,
Jennifer
Hello Jennifer, thank you for your comment. I only took the sample directly from the ethanol but did not wash it. Do you mean I have to wash by centrifuge with distilled water to remove the ethanol residue?
Hello Debbra,
At least try it out, it might be that the residual ethanol interferes in the first steps of the DNA extraction, even though ethanol is later applied to bind and wash the DNA. But you are sure, that your lysis buffer and the proteinase are working fine? Honestly, I don't know how difficult helminths are to lyse, but alternatively you might also try one of the additional steps suggested in the appendix used for bacteria or yeast.
you can follow this article https://www.ncbi.nlm.nih.gov/pmc/articles/PMC309567/pdf/nar00059-0231.pdf
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