Figure 2.

Multiorganism screen for antimicrobial peptides. As described elsewhere (13, 19), single library members were dissolved in the wells of a 96-well plate, the contents of which were then aliquoted into 3 additional 96-well replica plates. Buffer was added, followed by cells, to give 2.2 μM peptide in each well. After incubation, growth medium was added, and plates were incubated at 37°C overnight (for bacteria) or for 2 days for fungus. A) Representative E. coli plate after overnight incubation. Clear wells were sterilized, while opaque wells have stationary phase growth of microbes. Wells of the 11th column contained all of the components but no library peptides, while the 12th column contained buffer and growth medium but no cells. B–D) Schematic overlay representations of actual 3-plate sets. X indicates that E. coli was sterilized; red circle indicates that S. aureus was sterilized; blue bar indicates that the fungus C. neoformans was sterilized. E) Statistics for the multiorganism screen. Active peptides sterilized at least one microbe. Beads from the 4 broad-spectrum peptides were submitted for sequencing by Edman sequencing. Because of a malfunction, one was lost; thus, 3 complete sequences were obtained.