Polarization Fluorometry to Determine Cell Density with Fluorochrome for DNA

$29.00 plus tax (Refund Policy)

Buy Article:


There is a need for a rapid and sensitive technique to estimate a small number of cells. The total number of both living and dead cells suspended in a solution can be measured directly with the use of the Coulter counter or a flow-cytometer, but both of these measurements are inaccurate for small bacteria, such as an Escherichia coli cell (0.6 μm diameter × 2 μm length). The bacterial density is determined by the measurement of the turbidity of a cell suspension with a nepherometer or, more conveniently, with a spectrophotometer. However, foreign particles (e.g., dust, protein, or lipid) often increase turbidity and result in an error in the assay. Fluorometric assay for DNA content provides a sensitive estimation of the cell density free from turbidity changes. For example, Hill and Whatley used an antibiotic drug (mithramycin) as a labeling fluorochrome to measure cell DNA density with a lower limit of 0.5 μg. Recently, more sensitive quantification of DNA has been achieved with a bibenzimidazole dye, Hoechst 33258 (H33258). This dye reacts with the adenine-thymine-rich region of DNA, resulting in a high quantum efficiency for the determination. Downs and Wilfinger applied H33258 to quantify DNA measurement, and they achieved detection limits as low as 4 ng for extracted DNA from pituitary cells.

Keywords: Background correction; Determination of cell number; Fluorescence for DNA; Hoechst 33258 fluorochrome; Polarization fluorometry

Document Type: Short Communication

DOI: http://dx.doi.org/10.1366/0003702864815619

Affiliations: Laboratory for Cytochemistry, Department of Anatomy, School of Medicine, Tokushima University, Kuramoto, Tokushima 770, Japan

Publication date: January 1, 1986

More about this publication?
Related content



Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more