The culture was then inoculated into 500 mL (10% vol/vol) and periodically replenished with PCE as described above to an estimated cell density of 1.8 × 10 mL–1 (n = 3, sd = 7.8 × 10 mL–1) based on enumeration of 16S rRNA gene copy number as described below.
As therapy selection is increasingly done depending on exact thresholds, this clearly emphasizes the above mentioned fundamental need for a reliable method capable of objectively estimating cell densities in conglomerates.
The A660 nm reading was used to estimate the cell density in KT71T cultures.
This is because visual grading represents only an averaged estimate of cell density.
Elements of the QS apparatus of bacteria are now known to serve a wide variety of functions beyond a simple estimate of cell density [ 3, 4].
To estimate the cell density of bacteria over different culture durations, phase-contrast microscopy images of the culture channel were obtained and compared to control images in which the cell densities (10−10/mL) were measured by a hemocytometer.
Specific growth rate (μ, d-1) was calculated from daily estimates of cell density over 5 days (cell densities were estimated by counting 1 ml subsamples using a Sedgewick-Rafter chamber).
We then estimated B cell density on the entire lymph node sections using the Gaussian kernel density estimation method [8].
