Microbes and Environments
Online ISSN : 1347-4405
Print ISSN : 1342-6311
ISSN-L : 1342-6311
Regular Papers
Evaluation of the Effects of Different Additives in Improving the DNA Extraction Yield and Quality from Andosol
Seishi IkedaHirohito TsurumaruSatoshi WakaiChiaki NoritakeKeisuke FujishiroMariko AkasakaKatsuhiko Ando
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Keywords: casein, RISA, RNA, skim milk, soil DNA

2008 Volume 23 Issue 2 Pages 159-166


A series of additives were evaluated for their effects on improving the yield and quality of DNA extracted from recalcitrant soils. Levels of possible DNA contaminants in these supplements were also assessed. Three of the additives (skim milk, casein, and RNA) were shown to be effective in improving the stable extraction of DNA from recalcitrant samples of Andosol. However, whereas skim milk appeared to be the most effective additive for this purpose, our data indicated that this commercially sourced product contained considerable amounts of contaminant DNA (30 to 40 μg/g skim milk). A ribosomal intergenic spacer analysis (RISA) revealed the consistent contamination of different batches of this product with DNA of several species of both eukaryotes (cattle and protists) and prokaryotes. In particular, thermophilic bacteria such as Geobacillus and Anoxybacillus were identified in the sequenced PCR amplicons from skim milk. The results of the RISA clearly also indicated that the impact of contaminated DNA on the analysis of a microbial community could be significant when skim milk is used for extracting DNA from a recalcitrant soil. In contrast, only a trace amount of contaminating DNA was evident in casein and none was detected in the RNA examined in the present study.

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© Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology
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