Table 3.
Dual-strain combinations tested for intra-species interactions.
| Strains tested | Cell counts in dual biofilma (GM dual) | Cell counts in single biofilma (GM single) | GM dual b | Net result c | Type of interaction |
|---|---|---|---|---|---|
| GM single | |||||
| 5435-NT and 7632-15A | |||||
| 5435-NT | 5.37x107 | 4.28x105 | 1.25x102 | ↑ | Commensalism |
| 7632-15A | 2.05x108 | 8.10x108 | Ns | = | |
| 7632-15A and TIGR4 | |||||
| 7632-15A | 4.44x106 | 7.26x106 | Ns | = | “ |
| TIGR4 | 9.54x105 | 2.06x105 | 4.64x100 | ↑ | |
| 7031-NT and 7632-15A | |||||
| 7031-NT | 1.13x107 | 1.86x105 | ns | = | “ |
| 7632-15A | 2.97x108 | 1.07x108 | 2.77x100 | ↑ | |
| 7031-NT and TIGR4 | |||||
| 7031-NT | 3.08x104 | 1.03x106 | 3.00x10-2 | ↓ | Competition |
| TIGR4 | 5.51x104 | 2.73x105 | 2.02x10-1 | ↓ | |
| 1990-19F and 7632-15A | |||||
| 1990-19F | 6.87x104 | 1.12x106 | 6.12x10-2 | ↓ | “ |
| 7632-15A | 2.84x106 | 7.00x106 | 4.06x10-1 | ↓ | |
| 1990-19F and D39 | |||||
| 1990-19F | 2.92x105 | 1.21x106 | 2.41x10-1 | ↓ | “ |
| D39 | 1.83x104 | 2.53x105 | 7.22x10-2 | ↓ | |
| 6209-NT and TIGR4 | |||||
| 6209-NT | 1.66x105 | 3.46x106 | 4.80x10-2 | ↓ | “ |
| TIGR4 | 5.07x105 | 4.49x106 | 1.13x10-1 | ↓ | |
| 1990-19F and 7031-NT | |||||
| 1990-19F | 2.23x106 | 2.29x106 | ns | = | Amensalism |
| 7031-NT | 1.18x104 | 2.66x107 | 4.44x10-4 | ↓ | |
| 1990-19F and TIGR4 | |||||
| 1990-19F | 1.24x105 | 2.98x105 | ns | = | “ |
| TIGR4 | 1.99x104 | 2.10x105 | 9.47x10-2 | ↓ | |
| 5435-NT and 5756-22F | |||||
| 5435-NT | 7.05x106 | 8.23x106 | ns | = | “ |
| 5756-22F | 4.68x107 | 8.94x107 | 5.23x10-1 | ↓ | |
| 5756-22F and 6209-NT | |||||
| 5756-22F | 1.46x107 | 2.03x107 | ns | = | “ |
| 6209-NT | 1.39x106 | 4.78x106 | 2.92x10-1 | ↓ | |
| 5756-22F and 7031-NT | |||||
| 5756-22F | 1.84x107 | 1.25x107 | ns | = | “ |
| 7031-NT | 1.56x106 | 1.30x107 | 1.20x10-1 | ↓ | |
| 5756-22F and D39 | |||||
| 5756-22F | 5.46x105 | 9.62x105 | ns | = | “ |
| D39 | 4.61x105 | 1.07x106 | 4.31x10-1 | ↓ | |
| 5756-22F and TIGR4 | |||||
| 5756-22F | 3.60x104 | 1.44x106 | 2.49x10-2 | ↓ | “ |
| TIGR4 | 1.57x105 | 2.28x105 | ns | = | |
| 1990-19F and 5435-NT | |||||
| 1990-19F | 2.49x105 | 5.77x105 | ns | = | Neutralism |
| 5435-NT | 8.41x104 | 9.92x104 | ns | = | |
| 1990-19F and 5756-22F | |||||
| 1990-19F | 7.80x105 | 1.77x106 | ns | = | “ |
| 5756-22F | 4.33x105 | 5.84x105 | ns | = | |
| 5435-NT and 6209-NT | |||||
| 5435-NT | 1.13x105 | 4.83x105 | ns | = | “ |
| 6209-NT | 6.88x106 | 7.96x106 | ns | = | |
| 5435-NT and TIGR4 | |||||
| 5435-NT | 7.62x104 | 1.27x105 | ns | = | “ |
| TIGR4 | 7.40x104 | 6.79x105 | ns | = | |
| 5756-22F and 7632-15A | |||||
| 5756-22F | 4.84x106 | 3.55x106 | ns | = | “ |
| 7632-15A | 3.89x107 | 1.74x107 | ns | = | |
| 7031-NT and D39 | |||||
| 7031-NT | 3.57x105 | 2.79x106 | ns | = | “ |
| D39 | 7.61x105 | 1.62x106 | ns | = | |
| 7632-15A and D39 | |||||
| 7632-15A | 2.25x106 | 6.16x106 | ns | = | “ |
| D39 | 7.58x105 | 3.05x105 | ns | = | |
aCell counts, as a proxy of cell viability, were obtained by flow cytometry. Values indicate the geometric mean of 18 biological replicates (nine with GFP-labelling and nine with RFP-labelling) obtained for each strain in each condition (single-strain or dual-strain biofilm). The detailed results obtained for biological replica are presented in Figure 3 and Figure S2 .
The ratio between the geometric mean of cell counts of each strain in dual- and single-strain biofilms was calculated as a proxy of the strength of intra-species interaction. Results are only indicated when statistically significant differences were obtained following comparisons of the cell counts in dual- vs single-strain biofilms.
↑ strain benefits (i.e., cell counts increase) from growing in the presence of the other strain; ↓ strain is harmed (i.e., cell counts decrease) when growing in the presence of the other strain; = strain is not affected by the presence of the other strain.
ns, not significant.