The Turner BioSystems TD-700 Laboratory Fluorometer in combination with Molecular Probes' LIVE/DEAD® BacLightTM Bacterial Viability Kit provides a novel two-color fluorescence assay of bacterial viability that allows researchers to quantitatively distinguish live and dead bacteria in minutes, even in a mixed population containing a range of bacterial types. Conventional direct-count assays of bacterial viability are based on metabolic characteristics or membrane integrity. However, methods relying on metabolic characteristics often only work for a limited subset of bacterial groups,(1) and methods for assessing bacterial membrane integrity commonly have high levels of background fluorescence.(2) Both types of determinations suffer from being very sensitive to growth and staining conditions.(3,4)
The LIVE/DEAD BacLight Bacterial Viability assay utilizes mixtures of SYTO® 9 green fluorescent nucleic acid stain and the red fluorescent nucleic acid stain, propidium iodide. These stains differ both in their spectral characteristics and in their ability to penetrate healthy bacterial cells. When used alone, the SYTO 9 stain labels bacteria with both intact and damaged membranes. In contrast, propidium iodide penetrates only bacteria with damaged membranes, competing with the SYTO 9 stain for nucleic acid binding sites when both dyes are present. When mixed in recommended proportions, SYTO 9 stain and propidium iodide produce green fluorescent staining of bacteria with intact cell membranes and red fluorescent staining of bacteria with damaged membranes. The background remains virtually nonfluorescent. Consequently, the ratio of green to red fluorescence intensities provides a quantitative index of bacterial viability (Figure 1).
The Turner BioSystems TD-700 Laboratory Fluorometer in combination with Molecular Probes' LIVE/DEAD® BacLightTM Bacterial Viability Kit provides a novel two-color fluorescence assay of bacterial viability that allows researchers to quantitatively distinguish live and dead bacteria in minutes, even in a mixed population containing a range of bacterial types. Conventional direct-count assays of bacterial viability are based on metabolic characteristics or membrane integrity. However, methods relying on metabolic characteristics often only work for a limited subset of bacterial groups,(1) and methods for assessing bacterial membrane integrity commonly have high levels of background fluorescence.(2) Both types of determinations suffer from being very sensitive to growth and staining conditions.(3,4)
The LIVE/DEAD BacLight Bacterial Viability assay utilizes mixtures of SYTO® 9 green fluorescent nucleic acid stain and the red fluorescent nucleic acid stain, propidium iodide. These stains differ both in their spectral characteristics and in their ability to penetrate healthy bacterial cells. When used alone, the SYTO 9 stain labels bacteria with both intact and damaged membranes. In contrast, propidium iodide penetrates only bacteria with damaged membranes, competing with the SYTO 9 stain for nucleic acid binding sites when both dyes are present. When mixed in recommended proportions, SYTO 9 stain and propidium iodide produce green fluorescent staining of bacteria with intact cell membranes and red fluorescent staining of bacteria with damaged membranes. The background remains virtually nonfluorescent. Consequently, the ratio of green to red fluorescence intensities provides a quantitative index of bacterial viability (Figure 1).
การแปล กรุณารอสักครู่..
