A new modified protocol has been developed for extracting pure community inhibitors-free DNA from saline soils, sediments and salts. Amplification of DNA from soil and sediment is often inhibited by copurified contaminants. A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to saline samples. Using a widely used a newly modified direct DNA extraction method proposed in this report, DNA was extracted from samples of Urmia Lake in diverse geological location in Iran and quantity of the DNA were examined. We developed an improved method to extract DNA include the combination of physical, chemical and mechanical lysis methods from saline samples. In the earlier reports, skim milk as an adsorption competitor was added to buffer DNA extract. In current study, we added skim milk to buffer DNA extraction. The results showed that skim milk was useful as an additive for extract DNA from saline samples. This method is applicable to molecular community analysis of saline samples which strongly adsorb DNA. The methods appear to have wide applicability in investigating molecular diversity and exploring functional genes from the total DNA. The extracted DNA was used to successfully amplify 16SrRNA region and functional genes. The amplicons were suitable for further applications such as diversity based analysis by denaturing gradient gel electrophoresis (DGGE) and cloning library.
An Improved DNA Extraction Method Using Skim Milk from Soils That Strongly Adsorb DNA
