Table 1. DCS Chlamydia trachomatis plaque assay in the presence of natural and modified D-amino acids.
C. trachomatis serovar L2 strain 434/Bu was grown in the plaque assay as previously described4 in the presence of D-cycloserine (DCS) and varying molar equivalent concentrations of D-alanine (D-ala), D-alanine-D-alanine (DA-DA), EDA, DA-EDA, and EDA-DA.
| DCS (µM) | Amino acid, amino acid to DCS ratio |
Plaque formation |
|---|---|---|
| 0 | − | ++++ |
| 294 | No amino acid | − |
| Dipeptides | ||
| DA-DA, 1:1 | ++ | |
| DA-DA, 10:1 | +++ | |
| DA-EDA, 1:1 | − | |
| DA-EDA, 10:1 | +++ | |
| EDA-DA, 1:1 | − | |
| EDA-DA, 10:1 | ++ | |
| Single amino acids | ||
| D-ala, 1:1 | ++++ | |
| D-ala, 1:10 | +++ | |
| EDA, 1:1 | − | |
| EDA, 10:1 | − |
++++ complete infection, bacterial growth, and lysis of the monolayer; +++ numerous large plaques but less than complete lysis of the monolayer; ++ numerous small plaques; + few (~10–20) small plaques; −, no plaque formation (no bacterial growth). Data represent the average of three biological replicates and each experiment was conducted with technical duplicates.