TABLE 1.
Inhibition of NA accumulation by strain NFRI-95 by cyclo(l-Leu-l-Pro)-related substances as determined by the microtiter agar plate assaya
| Expt | Chemical(s) | Inhibition at the following concn:
|
|||||
|---|---|---|---|---|---|---|---|
| 0.1 mg ml−1 | 0.3 mg ml−1 | 1.0 mg ml−1 | 3.5 mg ml−1 | 6.0 mg ml−1 | 12.0 mg ml−1 | ||
| 1 | Cyclo(l-Leu-l-Pro) | − | − | ± | + | + | ND |
| Cyclo(d-Leu-d-Pro) | − | − | ± | + | + | ND | |
| 2 | Cyclo(l-Leu-l-Pro) | − | − | ± | + | + | ND |
| l-Leucine | − | − | − | − | − | ND | |
| d-Leucine | − | − | − | − | − | ND | |
| l-Proline | − | − | − | − | − | ND | |
| d-Proline | − | − | − | − | − | ND | |
| l-Leu + l-Pro | − | − | − | − | − | ND | |
| d-Leu + d-Pro | − | − | − | − | − | ND | |
| l-Leu + d-Pro | − | − | − | − | − | ND | |
| d-Leu + l-Pro | − | − | − | − | − | ND | |
| 3 | Cyclo(l-Leu-l-Pro) | − | − | ± | + | + | ND |
| Cyclo(l-Pro-l-Val) | − | ± | + | + | + | ND | |
| Cyclo(l-Leu-l-Gly) | − | − | − | − | ± | ND | |
| Cyclo(l-Gly-l-Pro) | − | − | − | − | − | ND | |
| Cyclo(d-Ala-l-Pro) | − | − | − | − | − | ND | |
| 4 | Cyclo(l-Leu-l-Pro) | − | − | ± | + | + | + |
| Cyclo(d-Leu-d-Pro) | − | − | ± | + | + | + | |
| Cyclo(d-Pro-l-Leu) | − | − | − | ± | + | + | |
| Cyclo(l-Pro-d-Leu) | − | − | − | ± | ± | ± | |
a
All chemicals were dissolved or suspended in methanol. Addition of only methanol did not inhibit NA accumulation. −, no effect; ±, partial inhibition; +, inhibition; ND, not determined.