EXCEED THE SPACE PROVIDED. This proposal describes the continuation of the National Resource for Aplysia, whose overall goal is to provide consistently high-quality cultured sea hares Aplysia californica (and their cultured red algal food, Gracilaria sp.) to NIH-sponsored researchers. Aplysia californica is an important non-vertebrate (Opisthobranch mollusc) model system for health-related research, primarily in the neurophysiology of behavior and learning. We will continue to produce animals for research, and to conduct basic research aimed at exploring new model uses and at improving the resource. There are four sub-projects/specific aims: 1. Production-We anticipate increasing our production of animals by approximately 25% per year during this next phase of funding and will make specimens from all life stages available at a price competitive with field- collected specimens. 2. Functional Genomics-We will undertake a cDNA/EST sequencing project of neural and other tissues from different developmental stages (larvae, juveniles, and reproductive and senescent animals), and use these cDNAs to produce microarrays. Following appropriate validation and quality control, these microarrays will be available for at-cost purchase by our user community, and will also be used to examine gene expression changes in our hatchery population during different developmental stages, and after exposure to other experimental conditions including variable temperature, egg-laying hormone administration, etc. All sequence and array experimentation data will be made available through web-based database access. 3. Developmental Neurophysiology- We will continue study of ion current modulation in the bag cells observed to vary with development, genetic background, and between hatchery reared and wild caught animals. Understanding electrophysiological correlates of growth and maturation are important to the Resource because they may affect the interpretation of data by users of the Resource. A correlative study will examine how different growth rates of the animals produce variations in development times for the nervous system changes that culminate in sexual maturity. 4. Animal Health Monitoring-We will continue a monitoring program based on screening of water quality and animal health parameters to assure rapid detection and complete documentation of any disease processes that might occur in any developmental stages of animals at the hatchery. Any disease syndromes and suspected pathogens observed will be investigated and appropriate control measures applied. Through this combination of production and basic research, we will improve the model system and extend its usefullness to other areas of research.