R/ODR-12

Description:

Our overall program objective is to determine the molecular and genetic basis for the factors which influence the Perkinsus marinus-Crassostrea virginica relationship by enhancing the disease process. For this purpose, we have established methodology tor cloning several potential virulence factors in P. marinus and are currently investigating genetics, regulation, and the biochemical aspects of specific factors that relate to specific host recognition, evasion of host defenses, proliferation and pathogenesis. However, basic questions, particularly concerning the parasite's genomic structure and diversity, remain unanswered. Therefore, we propose to accomplish the logical subsequent steps to our current research initiative, namely by (a) describing the size, structure, and diversity of the P. marinus genome, (b) the chromosomal localization of selected virulence factors, and (c) the development of the genetic tools and techniques required to assess their functions in host specificity, intracellular survival or pathogenesis. We propose to expand the development of vectors and techniques for the introduction of DNA sequences into P. marinus, characterize positively and negatively selectable markers that can be used in genetic studies, develop an insertional mutagenesis systern and design standardized quantitative assays to assess virulence of strains and their isogenic mutants.