Anti‐infection drug testing model; Part 1, L‐arginine

This is a simple and inexpensive model system that we use to assay the effects of reagents on dissociating yeast ( Saccharomyces cerevisiae ) bound to Concanavalin A (ConA) derivatized agarose beads and can be used for testing potential anti‐infection drugs. Here L‐arginine was tested for its ability to cause dissociation of yeast bound to the beads. A drop from a suspension of bead bound yeast cells was placed on a glass slide and drops of distilled water were placed beside the drop. Single yeast bound ConA beads were dragged into the yeast free distilled water drops. The numbers of yeast bound to each bead were counted under a microscope, followed by addition of 0M (control), 0.02M, 0.1M, 0.2M or 1.5M L‐arginine to the drops with the yeast bound beads. Counts of the yeast remaining bound to the beads were made at zero time, 20 min, 40 min and 60 min after arginine addition or no arginine controls with periodic mixing of the droplets. Data were analyzed using the general linear model and repeated measures statistics in the Systat 11 program, and an ANOVA test in the Systat 11 program, and graphs were generated using Microsoft Office Excel. Of the arginine concentrations tested, in a total of 80 trials, only 0.1M, 0.2M and 1.5M caused significant yeast dissociation from the beads compared to controls (p less than 0.05). Like on yeast and ConA beads, cell surface mannose residues and mannose binding receptors respectively are widely present on pathogens and on the human cells they infect, so this system could be used to mimic human cell/pathogen binding interactions in drug testing assays that are simple and inexpensive (Supported by NIH NIGMS MARC, SCORE (S0648680), RISE, the Joseph Drown Foundation, and the Sidney Stern Memorial Trust).