Title: Assistant Professor
Specialty: Environmental microbiology, biochemistry, arsenic biogeochemical cycle, antibiotics and resistance, drug discovery
Department(s): Cellular Biology and Pharmacology
Dr. Yoshinaga has been fascinated by metal(oid) detoxification/homeostasis since he started his research career. Dr. Yoshinaga earned his D.Sc. (Biology, 2007) from Hiroshima University, Japan, where he conducted a study on molecular mechanisms of vanadium accumulation by marine invertebrates. After the completion of the graduate study, he moved to the United States and started his new research career as an environmental microbiologist in Wayne State University. Dr. Yoshinaga joined in FIU HWCOM in 2009 and currently he is working as Assistant Professor in Department of Cellular Biology and Pharmacology. His specific area of interest is to understand the biotransformation of environmental organoarsenicals. Arsenic is the most pervasive environmental toxin, and massive amounts of organoarsenicals have been introduced into the environment as herbicides and antimicrobial growth promoters for animal husbandry. Those organoarsenicals are degraded into more toxic inorganic forms through microbial activities that impact the environment and contaminate crops and water supplies, yet little is known about the pathways and molecular mechanisms. His major accomplishments include discovery of a novel organoarsenicals degradation pathway. This emergent property of soil microbial communities is composed of two steps, reduction of the arsenic from pentavalent to trivalent by some members of the community and cleavage of the carbon-arsenic bond by other bacteria. Dr. Yoshinaga subsequently identified and cloned a responsible gene that he termed arsI encodes the only known C-As lyase for carbon-arsenic bond breakage and further characterized biochemical properties of the gene product ArsI and solved its crystal structure. He recently initiated a new project on arsinothricin (AST), the only known arsenic-containing antibiotic produced by rice rhizosphere bacteria. His results clearly demonstrate that AST is an effective broad-spectrum antibiotic, showing that bacteria have acquired the ability to utilize environmental arsenic to produce a potent antimicrobial. He further identified arsN, the gene that confers AST resistance, and characterized the molecular mechanism of the gene product ArsN. He employs interdisciplinary approach that emphasizes modern methods in analytical chemistry, biochemistry, microbiology, molecular and structure biology to challenge the knowledge gaps in the arsenic biogeochemical cycle as well as to acquire knowledge for applications such as bioremediation and drug development.