EVOGENE Seminar: Roger Simm

Cyclic di-nucleotide second messengers regulate virulence, stress survival and cation homeostasis in bacteria as well as transitions from single cells to microbial communities (biofilms). Cyclic-di-adenosine monophosphate is an essential signaling molecule in many gram-positive bacteria. We study the role of c-di-AMP in the oral commensal and opportunistic pathogen Streptococcus mitis. We use diverse methods to characterize the c-di-AMP signaling network, including turnover proteins and downstream receptors, and the phenotypes regulated by the second messenger.
Antibiotic resistance is a growing problem worldwide and a major threat to modern medicine and human health. Resistant bacteria are found everywhere in humans, animals and the environment, but are usually not considered a problem until they cause untreatable disease in humans. Ionophores are antimicrobial compounds used as feed additives in poultry feed to prevent coccidiosis and necrotic enteritis. A resistance mechanism to ionophores was recently discovered and found to be genetically linked to resistance against clinically used antibiotics in human opportunistic pathogens. In this project we examine the risks to human health associated with use of in feed ionophores, we characterize the ionophore resistance mechanism, and attempt to identify novel resistance mechanisms