Title: Mapping microbial responses to biological and chemical environments using omics

Abstract: Chemical crosstalk is universal to all life. This crosstalk is mediated by a large diversity of molecules including small molecules, metal ions, polysaccharides, nucleic acids, and proteins. Inter– and intraspecies communication using small molecules, referred to as natural products, allows microbes to sense quorum, form biofilms, evade attack, and respond to stress. Chemical crosstalk is circumstantial i.e. niche-specific, and essential to thrive. The Garg laboratory seeks to develop and apply mass spectrometry-based methods to 1) discover the role of chemical and biological environment in the regulation of crosstalk underlying microbe-drug, microbe-microbe, and microbe-host interactions, and to 2) discover small molecule natural products that fine-tune these interactions. Chemical discoveries are supported by the genetic manipulation of organisms, phenotypic assays, and by manipulation of the biological and chemical growth environments. This seminar will highlight recent progress in three research directions: 1) chemical interactions between human pathogens and clinically administered antibiotics, 2) the role of quorum sensing, bacterial pigmentation, and infection-relevant environment in the regulation of the production of microbial natural products, and 3) the description of natural product diversity as a guide to develop probiotics aimed at improving resilience of marine corals to secondary bacterial infections.