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Group Head



Abteilung Molekulare Ökologie

PD Dr. Bernhard Fuchs

MPI for Marine Microbiology
Celsiusstr. 1
D-28359 Bremen




+49 421 2028-935

PD Dr. Bernhard Fuchs

About our Research

Flow cytometry complements the molecular biological toolbox to study microorganisms. Its capacity of fast analysis of thousands of cells per second and the simultaneous recording of multiple parameters makes flow cytometry a standard tool in plankton research. In addition flow cytometric cell sorting (FACS) enables the physical separation and enrichment of well-defined cell populations without prior cultivation. 

In our group we continuously improve our flow cytometry methods and combine them with new molecular biological approaches to gain deeper insights into the ecological role of microbes in a range of diverse marine habitats.

What is Flow Cytometry?

Generally, flow cytometry is the measurement of single cells in a water jet.

We use flow cytometry routinely to quantify picoplankton samples and cell cultures. Pigments like chlorophyll and carotenoids characteristic for marine cyanobacteria and microalgae are detected as well as fluorescent dyes specific for DNA, proteins and other cellular compounds of microorganisms. Further, cells meeting predefined properties can be sorted with high speed for further analysis.

A simplified illustration of Flow Cytometry is given below.

Principle of a Flow Cytometer
Principle of flow cytometric analysis and sorting
© B. Fuchs / MPI-MM

Briefly, cells suspended in the sample are injected into a sheath fluid (top). Through the nozzle cells are focused into the center of the water jet. After leaving the nozzle cells are passing by the laser light in a single file like pearls on a string. The signals of the cells are recorded through detectors by a computing unit. Cells meeting defined parameters in the break-off point will be charged in their water droplet. The resulting charged droplet will be deflected into a vial. Depicted here is a two-way sort of two differently stained cell populations. Please refer to the literature for further details.

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