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Table 2 DNA quantification and purification values. Mean values with standard deviation (SD) for DNA concentration and purity of fecal samples collected and stored by three different collection/storage methods (Fresh, O24h, O7d) and extracted using two different procedures (PF, QIA)

From: Reliability of a participant-friendly fecal collection method for microbiome analyses: a step towards large sample size investigation

 

NanoDrop measurements (mean ± SD)

DNA concentration, ng/μL

260 nm/280 nm ratio

260 nm/230 nm ratio

Fresh + QIA

304.60 ± 106.35

1.86 ± 0.02

1.67 ± 0.20

O24h + QIA

267.22 ± 98.38a

1.88 ± 0.01

1.66 ± 0.16b

O7d + QIA

223.27 ± 100.03

1.88 ± 0.02

1.60 ± 0.19

O24h + PF

41.31 ± 32.52a

2.09 ± 0.39

1.02 ± 0.50b

  1. The ratios of absorbance at 260 nm/280 nm and 260 nm/230 nm are used to assess the purity of DNA. A ratio of ~ 1.8 is generally accepted as “pure” for DNA. If the ratio is appreciable lower, it may indicate the presence of contaminants (e.g. proteins, phenols or carbohydrates) (13, 14). aIs the comparison of DNA concentration (column labeled DNA concentration, ng/μL) and bof DNA purity (column labeled 260 nm/230 nm ratio) between QIA and PF DNA extraction methods (Bonferroni-adjusted paired sample t-test with P < 0.001 for all tests)