Related Experiment Videos
Density gradient separation of active and non-active cells from natural environments
A S Whiteley1, M R Barer, A G O'Donnell
1Centre for Molecular Ecology, University of Newcastle upon Tyne, UK.
Antonie Van Leeuwenhoek
|April 18, 2000
Summary
This study introduces a novel method to physically separate active and inactive bacteria from natural environments. The technique uses formazan crystal formation to distinguish and isolate bacterial cells based on their respiration activity.
Area of Science:
- Microbiology
- Environmental Science
- Biotechnology
Background:
- Distinguishing between metabolically active and inactive bacterial cells in natural communities is crucial for understanding microbial ecology.
- Current methods often lack the specificity or efficiency to isolate viable cells for subsequent molecular analysis.
- Understanding bacterial community structure and function requires methods that can differentiate cells based on their physiological state.
Purpose of the Study:
- To develop a selective, physical method for separating active and non-active bacterial cells from natural populations.
- To enable the molecular characterization of distinct bacterial subpopulations based on their in situ respiration potential.
- To investigate changes in bacterial community structure in response to environmental stimuli.
Main Methods:
- Exploiting the intracellular reduction of tetrazolium salts to formazan crystals in respiring cells.
- Utilizing the altered buoyant density of formazan-laden cells for separation via density gradient centrifugation.
- Analyzing separated cell fractions using Polymerase Chain Reaction (PCR) amplification and Denaturing Gradient Gel Electrophoresis (DGGE).
Main Results:
- Successful physical separation of active and non-active bacterial cell subpopulations from seawater samples.
- Distinct differences in PCR amplicon diversity observed between active and non-active cell fractions.
- Evidence of altered bacterial community structure correlated with the addition of oxidisable substrates.
Conclusions:
- The developed method allows for cytochemical enrichment and physical separation of bacterial cells based on respiration activity.
- This approach facilitates the molecular characterization of active and inactive bacterial communities in natural settings.
- The technique provides insights into bacterial community dynamics and responses to environmental conditions.