Discipline: Ecology Environmental and Earth Sciences
Subcategory: Cell and Molecular Biology
Adero Campbell - North Carolina A&T University
Co-Author(s): Jaminah Norman, North Carolina A&T University; Jude Akamu Ewunkem, North Carolina A&T University; Joseph L. Graves Jr., North Carolina A&T University
For the past three years our laboratory has utilized experiment evolution (EE) to rapidly evolve spherical silver nanoparticles (AGNP) and ionic silver (AgNO3) in E.coli K-12 MG1655. Previously we attempted to evolve resistance to silver triangular nanoplates (AgNPl) without success. It seems that the lack of adaptive response to AgNPLs suggests that these may be more efficacious in controlling silver-resistant bacteria. To test whether the lack of response to AgNPls is replicable, a second experiment was initiated. Initial culture concentrations were from 30μg/l to 90μg/l in a three-month span, the results showed that all 10 AgNPl-selected replicate flasks exhibited vigorous growth. Minimum inhibitory concentrations (MIC) for AgNPls were determined in generation 89 (~13 days) for both AgNPl-selected replicates and their controls (50 mg/l compared to 25 mg/l respectively). To test the limits of AgNPl tolerance in generation 601 (~92 days) the selection regime was increased to 500 μg/L. The next day at this concentration, growth was severely retarded AgNPl1, AgNPl8, and AgNPl9. At day 97 at this concentration, AgNPl1 rebounded, but AgNPl5—AgNPl10 were undetectable. At the same time AgNPl2–AgNPl4 were contaminated with a bacterium we determined to be Acinetobacter pili AgNPl5 was growing vigorously. These studies are ongoing but suggest that E. coli can evolve resistance to AgNPls, although the process is clearly more difficult that of spherical nanoparticles and ionic silver.Not Submitted
Funder Acknowledgement(s): BEACON
Faculty Advisor: Dr. Joseph Graves, email@example.com
Role: I did the daily transfers everyday, I analyzed the data and helped with sequencing the bacteria.