ANTIMICROBIAL PEPTIDES: A PARADIGM FOR NOVEL CHEMOTHERAPEUTIC AGENTS

Almost 80 years have passed since Dr. Alexander Fleming discovered penicillin, the first isolated antibiotic. However, due to improper usage, our once impressive array of antimicrobial agents is rapidly becoming ineffective. Infections that were once thought to have been conquered through the application of antibiotics have returned in the form of highly resistant strains. Indeed, hospitals worldwide have become inundated with, and a veritable breeding ground for, some of the most deadly bacteria. To combat this rapidly expanding problem, new and innovative antimicrobials must be found. The peptide defense systems of various species of amphibians have attracted considerable interest. The presence of numerous antimicrobial peptides in frog skin, acting separately or synergistically, may enhance survival in habitats laden with opportunistic and pathogenic microorganisms. This impressive peptide armament differs among frogs belonging to different families, genera, species and even subspecies. Results showed that no two species that have the same array of peptides have yet been found. Our study also demonstrated that Eleutherodactylus johnstonei, a species of frog native to Grenada and widely distributed throughout the Caribbean, does indeed produce antimicrobial peptides (preliminarily named Johnerin-1 and Johnerin-2) and that these peptides exhibit a broad spectrum of activity against target bacterial isolates. This project has the potential to open new avenues towards the development of novel chemotherapeutic agents and, at the very least, increase our understanding of the amphibian innate immune system