Biology Graduate Student Spotlight: Thushinari Joseph

By: Gabby Wetwiski

Meet Thushinari Joseph!

I’m a sixth year Ph.D. candidate in Dr. James Smith’s lab. I was born and raised in Sri Lanka, a tropical island with a rich history and culture also known as the pearl of the Indian ocean. I received my bachelor’s degree there, from the University of Kelaniya while studying fecal coliform densities in and isolation of biochemically significant bacteria from beach sand for my undergraduate research. My current research is on the characterization of lantibiotics which involves the regulation of mutacin 1140 biosynthesis and isolation of a nisin variant from Streptococcus agalactiae. Additionally, I also work on pre-clinical evaluation of antimicrobial compounds in mice models.

What is one thing people would be surprised to know about you?

Growing up I learnt Kandyan dancing (oriental form of dancing in Sri Lanka). If I had not chosen to be a scientist, I would have gone down the path of performing arts.

What is the best advice you have ever received?

Live with empathy and compassion and help others as much as possible.

What is the broader significance of your research?

Antibiotic resistance is a significant public health threat and a financial burden on the health care system. This has resulted in a growing demand for alternative drugs to treat multi-drug-resistant bacterial infections. Mutacin 1140 belongs to a novel class of therapeutic agents called lantibiotics. Lantibiotics are ribosomally synthesized and post translationally modified peptide (Ripp) antibiotics, which are used to treat serious bacterial infections. Although mutacin 1140 has demonstrated activity against several Gram-positive pathogens which include oxacillin- and vancomycin-resistant Staphylococcus aureus and vancomycin-resistant E. faecalis, the regulation of its biosynthesis has not been explored. The aim of my project is to characterize the regulatory mechanisms of its biosynthesis which will then lead to the development of novel mutacin 1140 based therapeutic agents that can be used to treat systemic Gram-positive bacterial infections.

How has a research career had an impact on your thinking?

Entering the world of research was a life-changing opportunity I experienced during my bachelors. Since then, it has enabled me to take more of an analytical approach to problems, and it continues to stimulate my intellectual curiosity.

Tell us about a project or accomplishment that you consider to be the most significant in your career.

First would be the isolation of a novel nisin variant from the gastrointestinal bacterium Streptococcus agalactiae, which was like solving a puzzle. Starting with a strain of unknown identity to isolate and characterize the antimicrobial compound produced by that strain was an intriguing experience. Secondly, establishing the efficacy of mutacin 1140 analogs in systemic and cutaneous methicillin-resistant Staphylococcus aureus infection models in mice was a significant turning point of my journey of the preclinical studies of antimicrobial compounds.