Clardy's early research focused on the structure elucidation of natural products primarily by
X-ray crystallography. Early on at Iowa State University Clardy established important collaborations with Bill Fenical, John Faulkner and Paul Scheuer, which led to the structure elucidation of numerous marine natural products such as the anticancer agent
bryostatin, the insecticidal and antifungal
jaspamide,
diazonamide A and
B, and many others. Some of his most notable early work focused on the neurotoxins associated with "red tide" – which led to the determination of the three dimensional structures of
saxitoxin, of the
gonyautoxin group, and the cyclic polyether
brevetoxin B. Upon moving to Cornell University, Clardy's research expanded to include a huge variety of non-marine organisms including, but not limited to, fungi,
Actinomycetota and
C. elegans. His longstanding interest in endophytic fungi led to the discovery of the selectively cytotoxic quinone
torreyanic acid, the structurally diverse
guanacastepenes, the antimycotic agent
cryptocin, and many others. Recently, Clardy has focused on symbiotic associations between bacteria and other organisms as rich sources of novel small molecules. In collaboration with Cameron Currie, Clardy investigated associations between Actinomycetes and insects such as the southern pine beetle, ants and termites that led to the discovery of antifungal agents including
dentigerumycin and mycangimycin. The study of chemical exchange in complex ecological interactions remains a central focus of the Clardy lab. ==X-ray crystallography of small molecule – protein interactions==