The instrument development work described here will greatly expand and enhance the capabilities of our existing ("prototype") high sensitivity flow cytometer for the analysis of natural microbial populations. Specifically, we propose to: . Install an argon-krypton mixed gas laser to provide a wide choice of excitation wavelengths. . Add the optics and electronics required for dual beam excitation and 4 channel detection. . Develop a highly flexible data acquisition system based on off-the-shelf electronics modules. . Interface the flow cytometer with a real-time neural net-based data analysis system. The instrument will be used to develop methods of identifying and enumerating specific microorganisms in natural samples (based on 16S rRNA-targeted oligonucleotide probes), and of analyzing in situ physiological parameters (using more traditional cytochemical techniques). The flow cytometer will also be used to support ongoing studies of cell cycle regulation in bacteria and microalgae.
