Environmental Microbiology

Michael Leonardo

Research opportunities with Dr. Leonardo are available to students with a variety of academic backgrounds. Currently, biofilm formation is the primary focus in his lab. In nature, biofilms are mixed communities of bacteria and is a common survival strategy of many bacteria. One key aspect of community development and biofilm formation is cell-cell communication amongst the bacterial community members. Dr. Leonardo’s lab is exploring the interactions of two genera of bacteria that are co-inhabitants of overlapping niches: the marine pathogen Vibrio parahaemolyticus and diverse Shewanella species. In V. parahaemolyticus and several marine species of Shewanella, biofilm formation is controlled by a cell-cell signaling molecule called the S-signal. Preliminary investigations show that there is cross-talk between the Vibrio and Shewanella S-signal systems. To determine the impact of this intercellular cross-talk, we will approach this on two fronts, genetically and in vivo. We will be developing a plasmid-borne SCARless system for CRISPR-generated mutations in the S-signal production and response in Shewanella. Gene expression will be monitored by qPCR and other methods. In addition, we will grow biofilms using different combinations of Vibrio and Shewanella strains then use confocal laser-scanning fluorescent microscopy to study the architecture of biofilms. We will also use classic microbiological protocols to determine if the two genera are antagonistic to each other or not within the biofilms.

Dr. Leonardo is a member of the Coe College Biology Department mleonard@coe.edu