TABLE 1.
Initial rates of release of 14CO2 from hexanoyl-l-[1-14C]HSL by soil communities and other environmental samples
| Sample type | Sample pH | Hexanoyl-HSL mineralization at pH 6.0 and 32°C (nmol · h−1 · g of fresh weight−1)a |
|---|---|---|
| Turf soil (Calif.) | 6.6 | 13.4 ± 0.9 |
| Spring wheat soil, Take-All suppressive (Wash.) | 4.8 | 4.4 ± 0.5 |
| Spring wheat soil, nonsuppressive (Wash.) | 4.9 | 4.9 ± 0.8 |
| Winter wheat soil (Wash.) | 5.4 | 4.9 ± 0.4 |
| Corn-soybean-wheat rotation soil, standard chemical inputs (Mich.) | 5.8 | ≤0.1b |
| Corn-soybean-wheat rotation soil, organic inputs only (Mich.) | 5.7 | 2.2 ± 0.1 |
| Poplar soil (Mich.) | 6.0 | 2.4 ± 0.3 |
| Alfalfa soil (Mich.) | 6.0 | 3.7 ± 0.2 |
| Surrogate native soil (Mich.) | 4.8 | 2.5 ± 0.4 |
| Late successional forest soil (Mich.) | 4.8 | 2.5 ± 0.1 |
| Early successional forest soil (Mich.) | 4.8 | 2.2 ± 0.3 |
| Conifer plantation soil (Mich.) | 4.3 | 2.1 ± 0.1 |
| Zootermopsis termite guts (Calif.) | ∼7 | ≤0.1c |
a
Rates represent linear kinetics observed over the initial 2 h of incubation with 10.3 ± 0.5 μM [14C]C6HSL at 32°C and pH 6.0, conditions found to be optimal for C6HSL mineralization by Caltech turf soil. Reactions were performed at least in duplicate.
b
After a 4-h lag, mineralization proceeded at a linear rate of 2.0 ± 0.1 nmol·h−1·g of fresh weight−1.
c
After a 6-h lag, mineralization proceeded at a linear rate of 10.1 ± 0.3 nmol·h−1·g of fresh weight−1.