TABLE 1.
Variability in quantification of bacterial and Nitrospira 16S rRNA gene targets in mixed-liquor samples by real-time PCR
| Data points | Avg CVa ± SD
|
||||||
|---|---|---|---|---|---|---|---|
| DNA yield (μg/mg)b | Bacteria (CT) | Nitrospira (CT) | Bacteria (copies/liter)c | Nitrospira (copies/liter)c | Bacteria (copies/μg)d | Nitrospira (copies/μg)d | |
| 12 mixed-liquor samplese | 12.2 ± 9.2 | 1.8 ± 1.4 | 2.1 ± 1.0 | 19.5 ± 15.9 | 36.0 ± 15.3 | 19.1 ± 9.3 | 34.6 ± 17.2 |
| 36 DNA extractionsf | —g | 1.9 ± 1.5 | 1.9 ± 1.4 | 21.9 ± 18.2 | 29.8 ± 21.7 | 22.0 ± 18.2 | 34.1 ± 29.4 |
a
CV is the standard deviation expressed as a percentage of the mean.
b
Micrograms of DNA per milligram of MLVSS.
c
Copies per liter of mixed-liquor.
d
Copies per microgram of DNA.
e
Coefficient of variation based on the mean from three extractions per sample in each of the 12 samples.
f
Coefficient of variation based on the mean from triplicate measurements of the real-time PCR assay in each of the 36 DNA extractions.
g
No coefficient of variability was determined because there was only one DNA yield per extraction.