TABLE 3.
H2O2 can be detected in biofilms at the onset of cell death, and the addition of catalase prevents biofilm cell death
| Biofilma | Fluorescence type | Scoreb
|
|||||||
|---|---|---|---|---|---|---|---|---|---|
| P. tunicata wild type | ΔAlpP mutant | M. mediterranea wild type | SB1 mutant | C. violaceum wild type | CVMUR1 | C. crescentus wild type | CAUMUR1 | ||
| In minimal medium | PI fluorescence (dead cells) | +++ | - | +++ | - | +++ | - | +++ | ++ |
| AR fluorescence (H2O2) | +++ | - | +++ | + | +++ | - | ++ | ++ | |
| In minimal medium plus catalase | PI fluorescence (dead cells) | + | - | - | - | - | - | + | - |
| AR fluorescence (H2O2) | - | - | + | + | - | - | - | - | |
a
Two sets of triplicate biofilms were inoculated for each strain, one set in minimal medium and the other set in minimal medium with the addition of catalase (100 μg ml−1) after 24 h. Biofilms were allowed to establish for 4 days before staining with the BacLight LIVE/DEAD viability kit to detect cell death and with the Amplex Red (AR) reagent to localize hydrogen peroxide, as indicated in column 2.
b
The fluorescence intensity was scored as follows: +++, high; ++, medium; +, low; -, none.