A user group of five NIH-funded investigators requests funds to purchase a Union Biometrica BIOSORTER- PRO large-particle flow cytometer. A primary application of the instrument is sorting, measuring, and otherwise handling worms, specifically the common laboratory model organism Caenorhabditis elegans. The ability to handle samples in an automated, high-throughput fashion, with the additional ability to discriminate between individuals carrying fluorescent markers (e.g., green fluorescent protein, GFP), will transform both the kind and the magnitude of projects feasible to the users. The major users primarily or exclusively employ C. elegans in their research programs. The inherent power of C. elegans as a model system in biomedical research resides in its biological simplicity, its small size, and its rapid generation time. These features mean that the properties of the organism itself rarely limit the throughput of an experiment. Rather, the limitations are practical ones imposed by the inherent difficulty of scoring traits on individuals that are (almost microscopic in size. The great value of the worm sorter is to greatly increase the potential throughput of a wide variety of experiments, thereby allowing the users to leverage the inherent utility of the C. elegans system to its fullest potential. However, the instrument as outfitted her is capable of handling a diverse variety of organisms and cells, and its applications extend far beyond worm biology. An additional group of 11 minor users (most NIH- funded) have disparate applications including Drosophila, human pancreatic islets, Aplysia neurons, Axolotl embryos and marine invertebrate larvae. The instrument will be located in and managed by the University of Florida Interdisciplinary Center for Biotechnology Research Flow Cytometry core facility. There is currently no such instrument located in the state of Florida. The major users are located at the University of Florida and the University of Miami;minor users are situated both at UF and at other institutions around the state of Florida. In addition to greatly advancing the individual research programs of the users, the availability of the instrument in a central location in the state of Florida will provide an important regional resource and foster collaborative research throughout the state.