Presentation description

Since 1975, antibiotic discovery has slowed, while the number of antimicrobial-resistant bacteria has risen steadily. Worldwide, over one million people die each year from antimicrobial-resistant bacteria, resulting in an urgent demand for new antimicrobials. Fortunately, several biosynthetic gene clusters (BGCs) with the potential to produce antimicrobial drugs have been discovered in bacteria. However, the majority of these BGCs appear inactive, or "silent," when grown in a lab setting. Successful approaches to systematically activate the BGCs would have a profound impact on antimicrobial discovery. The purpose of this research was to investigate an underexplored source of silent BGCs in methanotrophs, or methane-oxidizing bacteria. Previous research has found that Methylocystis sp. strain SC2, a methanotroph in the alphaproteobacterial class, has a silent BGC potentially encoding for a lanthipeptide synthetase. Not only are lanthipeptides typically not seen in alphaproteobacteria, but different lanthipeptides have been found to have antimicrobial, antiviral, or antibacterial activities. By activating the silent BGC, the proposed lanthipeptide could be analyzed for its antimicrobial properties. To monitor activation of the BGC, a reporter strain for Methylocystis sp. strain SC2 was prepared by replacing the lanthipeptide synthetase (lanM) gene with a xylE gene. xylE encodes for a catechol dioxygenase, which produces an observable color change when the BGC is activated in the presence of catechol. By utilizing a high-throughput method with various compounds, several potential elicitors of the BGC have been identified, including ethylene diamine and alpha-caprylic acid. The elicitors will be used to activate the wildtype BGC and isolate the prospective lanthipeptide for further testing.