This is a Career Advancement Award which allows Dr. Salyers to develop new genetic tools for understanding metabolic strategies of Bacteroides bacteria. Specific aims are to (l) Construct a derivative of an insertion sequence that could be used to detect Bacterioides genes on the basis of their regulatory properties, (2) Use a fusion of the Emr gene to the chondroitin lyase II promoter to select for mutations that lead to constrituitive expression of genes in the chondroitin sulfate breakdown system, (3) construct a cosmid shuttle vector that can be mobilized into Bacteroides and is maintained in Bacteroides as a plasmid, and (4) Obtain and characterize transposon mutants in the alpha-galactoside utilization system of B. ovatus, and to place them in complementation groups using a library of B. ovatus DNA cloned in the cosmid shuttle vector.