The simple eukaryote Dictyostelium discoideum is a model organism widely used for the study of cellular processes such as cell motility, chemotaxis, cellular differentiation, signal transduction, the molecular basis of human diseases, the response to drugs and the cellular mechanisms of drug resistance. As a soil dweller that must compete and defend itself against other micro-organisms, it produces a vast array of secondary metabolites that could be of medical interest. Its ability to recognize itself from other cells with which it bears varying degrees of genetic relationship makes it an fascinating model for the study of self/non-self recognition in microbial ecosystems. Moreover, its phylogenetic position at the intersection between plants and animals makes it a useful organism to include in comparative genomics studies. All those studies require the use of strains, either wild type variants or genetically modified. Since 2002, the Dictyostelium research community has benefited from the presence of a central Stock Center. This resource provides a cost-effective means of ensuring that strains are available and maintained in standardized conditions. The Stock Center is currently overseen by Richard Kessin and Jakob Franke (Columbia University) who will retire at the end of the current funding period. This application seeks support to carry on collecting the known species of social amoebae and isolates of well-studied species like D. discoideum and D. purpureum, in addition to genetically modified strains that have interesting phenotypic characteristics. This provides a great opportunity to move the Stock Center and the Dictyostelium discoideum genome resource, dictyBase, closer together. Northwestern University is the host for dictyBase, making Northwestern the most natural choice for housing the Stock Center. The goals of this proposal are twofold: (1) maintain and expand the Stock Center collection by continuing to collect new natural isolates of Dictyostelium and related organisms, mutants that produce phenotypes, marked strains, as well as valuable resources such as cDNA libraries and antibodies; and (2) distribute the materials from the Stock Center to the research community. The Dicty Stock Center has established standard operating procedures for receiving, testing and storing strains and plasmids that we will commit to continuing these policies an procedures as they have been very successful in providing service to the community.