We genetially engienered several strains of E. coli in an effort to increase copper resistance and collection. We named each strain after our school's mascot, the Chesapeake Bay Retriever. Retriever 1 (Ret1) has been given the yeast metallothionein gene CUP1. Retriever 2 (Ret2) has been given the same CUP1 gene codon optimized for E. coli. Each strain was tested for cell density and extracellular copper concentration at different initial copper sulfate concentrations for 7 hours.