This award is co-funded by the Systems and Synthetic Biology Cluster in the Division of Molecular and Cellular Biosciences and the Chemistry of Life Processes Program in the Division of ChemistryThe overall goal of this project is to understand soil bacterial activities that significantly increase toxicity of environmental arsenic introduced through agricultural practices. The results may provide useful information for lessening environmental arsenic pollution. Other project outcomes could furnish useful information for the development of more effective herbicides and anti-infective drugs for farm animals and herbicide-resistance crops. The project involves the use of biochemical and genetics methods that examine the degradative pathways for organoarsenicals. The project contributes to the education and research training of students. The project is performed at Florida International University which is a minority-serving urban public research institution in Miami. There are opportunities for broadening the exposure students of underrepresented groups to science.Methyl and aromatic arsenicals have been used as herbicides and anti-infective drugs respectively, for farm animals. These organoarsenicals are degraded into more toxic inorganic forms through microbial activities, leading to environmental pollution. Previously the Principal Investigator (PI) identified a novel organoarsenical degradation pathway that is composed of multiple steps catalyzed by a soil bacterial community. The PI further identified one novel gene involved in organoarsenical degradation and biochemically characterized the encoded enzyme. However, the pathways and molecular mechanisms of organoarsenical degradation are still largely unknown. The project employs combined approaches of genetics, analytical chemistry, biochemistry, microbiology, molecular and structural biology to identify and characterize major molecular components in the degradative pathways for environmental organoarsenicals. The knowledge obtained through this project may elucidate the ways that microbes change the environment through biotransformation of anthropogenic organoarsenicals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.