Counting viruses with a flow cytometer
Bacteria inundate the Earth's oceans. Scientists have come to understand that these microscopic creatures are critical players in the cycling of important nutrients like carbon and sulphur. As mankind's impact on the oceans and the overlying atmosphere continues to intensify, it is imperative that we improve our knowledge regarding these bacteria. This was the aim of the three-year BASICS project supported by the Fifth Framework Programme. During BASICS the Centre national de la recherche scientifique (CNRS) was assigned to the task of investigating the influence of viruses present in seawater on bacteria. As part of their research, CNRS had to accurately measure the number of viruses present in a given sample of seawater. To do so they used a flow cytometer, an instrument commonly used to count blood cells. During the course of BASICS, CNRS scientists created a protocol for a specific flow cytometer (Becton Dickinson FACSCalibur). The high quality and quantity of data made possible by the protocol enabled CNRS to analyse a large number of samples. Interpretation of the data by CNRS and its BASICS partners will help provide insight into the complex relationship between bacteria and viruses. It should be noted that the protocol can be extended to other models and types of flow cytometers.
