Seminar: Donald C. Hall, Jr. (DJ), Ph.D.

Department of Biochemistry and Microbiology

 Fermentation Club Seminar Series | Fall 2026

Speaker: 

Donald C. Hall, Jr. (DJ), Ph.D., Assistant Professor Microbiology & Immunology Drexel University College Of Medicine

Host: Rohan Maddamsetti, Ph.D.

Title: Exploiting the Bacterial Stringent Response: From RSH Biology to Therapeutic Intervention

The bacterial stringent response, controlled by RelA/SpoT homolog (RSH) enzymes and the alarmone (p)ppGpp, is a central regulator of bacterial adaptation to environmental stress and has important roles in virulence and antibiotic tolerance. Our work seeks to define how disruption of RSH signaling alters bacterial pathogenesis and whether this conserved stress response can be exploited therapeutically. Using genetic and chemical approaches, we are investigating the consequences of stringent-response disruption across clinically important bacterial pathogens, with a particular focus on Pseudomonas aeruginosa. Building on genetic and phenotypic findings reported for stringent-response mutants across multiple bacterial species, we are extending our studies to determine whether pharmacological disruption of the stringent response produces similar effects across clinically important pathogens. This work includes the identification and characterization of HEJ14, a candidate RelA inhibitor that attenuates virulence and enhances antibiotic killing in P. aeruginosa, as well as ongoing studies evaluating RSH-associated phenotypes and the activity of HEJ14 in additional pathogens and infection models. Together, this work explores the bacterial stringent response as a potential target for novel anti-virulence and antibiotic-potentiating strategies.