(25) Assay Card

General Information
Summary RTD-1 found to possess anti-microbial activity greater than the acyclic analogue.
Result The broad spectrum of RTD-1 antimicrobial activity was demonstrated in microbicidal assays against Gram-positive bacteria (S.¬aureus, Listeria monocytogenes), Gram-negative bacteria (E.¬coli ML 35,¬Salmonella typhimurium), and fungi (Candida albicans and Cryptococcus neoformans). The viability of each organism was reduced by more than 99% after 2-hour incubations with 2¬to 4¬ug/ml RTD-1, and higher peptide concentrations (up to 20¬ug/ml) effected killing to levels below the detection limit of the assay. RTD-1 and acyclic RTD-1 were tested for activity against S. aureus and E. coli in an agar diffusion antimicrobial assay (6). RTD-1 was three times as active as the acyclic analog against both organisms, indicating that cyclization confers a substantial increase in antimicrobial potency
AssayType Anti-bacterial

Tang YQ, Yuan J, Osapay G, Osapay K, Tran D, Miller CJ, Ouellette AJ, Selsted ME (1999) A cyclic antimicrobial peptide produced in primate leukocytes by the ligation of two truncated alpha-defensins. Science 286:498-502

Proteins Assayed RTD-1