Table I.
The pBR322 plasmid DNA single-strand breaks induced by benzene metabolites in the absence or presence of the NO-releasing compound (DEA-NO).a
| Benzene metabolites | SSB per 104 bp DNAb Absence of DEA-NO |
SSB per 104 bp DNAb Presence of DEA-NO |
Ratio of DNA single-strand breakage Presence/absence of DEA-NO |
|
|---|---|---|---|---|
| Control | - | 0.07±0.009 | 0.07±0.009 | 1.0 |
| HQ | - | 0.14±0.028 | 3.70±0.160 | 26.4 |
| BT | - | 3.48±0.038 | 3.96±0.100 | 1.1 |
| CAT | - | 0.07±0.008 | 1.15±0.200 | 16.4 |
| BQ | - | 0.08±0.026 | 1.13±0.079 | 14.1 |
| Phenol | - | 0.07±0.028 | 0.16±0.032 | 2.3 |
| Benzene | - | 0.07±0.009 | 0.07±0.007 | 1.0 |
| trans, trans-MA | - | 0.07±0.040 | 0.14 ±0.050 | 2.0 |
| HQ | CAT | 0.12±0.060 | 4.88±0.027 | 40.6 |
| HQ | BT | 1.14±0.120 | 3.38±0.080 | 3.0 |
| HQ | Phenol | 0.12±0.048 | 6.44 ±0.041 | 53.6 |
| HQ | BQ | 0.25±0.068 | 3.36±0.580 | 13.4 |
| CAT | BT | 0.87±0.210 | 2.58±0.095 | 3.0 |
| CAT | Phenol | 0.10±0.030 | 1.34±0.039 | 13.4 |
| BT | Phenol | 1.47±0.480 | 3.27±0.081 | 2.2 |
a
Incubations included pBR322 DNA (100 ng), DEA-NO (1 mM) and benzene metabolites (0.25 mM). Data are the means of at least three different experiments.
b
Single-strand DNA breakage is calculated based on the Possion formula as described in Material and methods (35).